JP2011117987A - Positive resist composition and method for forming resist pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive resist composition excellent in lithographic characteristics such as a resolution and a mask error factor (MEF), and to provide a method for forming a resist pattern using the positive resist composition. <P>SOLUTION: The positive resist composition contains a base component (A) whose solubility with an alkali developing solution is increased by the action of an acid, an acid generator component (B) generating an acid by exposure, and a nitrogen-containing organic compound (D). The base component (A) contains a polymer compound (A1) that has a (meth)acrylate unit (a0) having an ester group having a cyclic group including -SO<SB>2</SB>- in the cyclic skeleton coupled with a divalent linking group in a side chain, and contains an acid dissociable dissolution-inhibiting group in the structure. The nitrogen-containing organic compound (D) contains an amine (D1) containing at least one kind selected from a group composed of an ethereal oxygen atom, an ester group, a carbonyl group, a cyano group, a phenyl group which may have substituents, and a nitrogen-containing heterocyclic group. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a positive resist composition and a resist pattern forming method using the positive resist composition.

In lithography technology, for example, a resist film made of a resist material is formed on a substrate, and the resist film is selectively exposed to light such as light or an electron beam through a mask on which a predetermined pattern is formed. And a development process is performed to form a resist pattern having a predetermined shape on the resist film.
A resist material in which the exposed portion changes to a property that dissolves in the developer is referred to as a positive type, and a resist material that changes to a property in which the exposed portion does not dissolve in the developer is referred to as a negative type.
In recent years, in the manufacture of semiconductor elements and liquid crystal display elements, pattern miniaturization has rapidly progressed due to advances in lithography technology.
As a technique for miniaturization, the wavelength of an exposure light source is generally shortened. Specifically, conventionally, ultraviolet rays typified by g-line and i-line have been used, but at present, mass production of semiconductor elements using a KrF excimer laser or an ArF excimer laser has started. In addition, studies have been made on F ₂ excimer lasers, electron beams, EUV (extreme ultraviolet rays), X-rays, and the like having shorter wavelengths than these excimer lasers.

Resist materials are required to have lithography characteristics such as sensitivity to these exposure light sources and resolution capable of reproducing a pattern with fine dimensions.
As a resist material that satisfies such requirements, a chemically amplified resist composition containing a base material component whose solubility in an alkaline developer is changed by the action of an acid and an acid generator that generates an acid upon exposure is used. ing.
For example, as a positive chemically amplified resist composition, a composition containing a resin component (base resin) whose solubility in an alkaline developer is increased by the action of an acid and an acid generator component is generally used. Yes. When such a resist film formed using the resist composition is selectively exposed at the time of resist pattern formation, an acid is generated from the acid generator in the exposed portion, and the alkali developer of the resin component is generated by the action of the acid. As a result, the exposed area becomes soluble in an alkaline developer.
Currently, as a resist base resin used in ArF excimer laser lithography and the like, a resin (acrylic resin) having a structural unit derived from (meth) acrylic acid ester in its main chain because of its excellent transparency near 193 nm Etc. are generally used (see, for example, Patent Document 1). Here, “(meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position. “(Meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position. “(Meth) acrylate” means one or both of an acrylate having a hydrogen atom bonded to the α-position and a methacrylate having a methyl group bonded to the α-position.
At present, in addition to the base resin and the acid generator, nitrogen-containing organic compounds such as alkylamines and alkylalcoholamines are blended into the chemically amplified resist (for example, Patent Documents 2 to 3). The nitrogen-containing organic compound acts as a quencher that traps the acid generated from the acid generator, and contributes to the improvement of lithography properties such as the resist pattern shape.

JP 2003-241385 A Japanese Patent Laid-Open No. 5-249662 JP-A-5-232706

In the future, there are demands for new materials that can be used for lithography applications, as further progress in lithography technology and expansion of application fields are expected. For example, as the pattern becomes finer, the resist material is also required to improve various lithography properties such as resolution.
As a result of intensive studies in view of such circumstances, the present inventors have found that a polymer compound containing a structural unit (a0), which will be described later, as a base material component contributes to the improvement of lithography properties. A positive resist composition containing a compound has been proposed (Japanese Patent Application No. 2009-185958).
However, according to further studies by the present inventors, the positive resist composition exhibits superior lithography characteristics as compared with conventional ones, but there is a limit in improving the resolution. Further, it cannot be said that the mask error factor (MEF) is sufficient, and further improvement thereof is required. The MEF is a parameter indicating how faithfully a mask pattern having a different size can be reproduced (mask reproducibility) when the mask size is changed with the same exposure amount and a fixed pitch. In a conventional resist composition, the resist pattern is formed as a result of an increase or decrease in the amount of light applied to the exposed portion due to changes in the mask size (hole diameter in the hole pattern or line width in the line and space pattern) used in forming the resist pattern. There is a possibility that the size of the resist pattern deviates from the mask size or the shape may be collapsed when a fine pattern is formed at a narrow pitch. For example, when a hole pattern having a hole diameter of about 100 nm or less is formed, the hole may have a low roundness.
The present invention has been made in view of the above circumstances, and provides a positive resist composition excellent in resolution and MEF and other lithographic properties, and a resist pattern forming method using the positive resist composition. Is an issue.

As a result of intensive studies, the present inventors have found that the above problem can be solved by combining the above polymer compound with a specific nitrogen-containing organic compound, and have completed the present invention.
That is, the first aspect of the present invention is a substrate component (A) whose solubility in an alkaline developer is increased by the action of an acid, an acid generator component (B) that generates an acid upon exposure, and a nitrogen-containing organic compound. A positive resist composition containing (D),
The base material component (A) has a structural unit (a0) represented by the following general formula (a0-1) and contains an acid dissociable, dissolution inhibiting group in its structure (A1) Containing
The nitrogen-containing organic compound (D) is selected from the group consisting of an etheric oxygen atom, an ester group, a carbonyl group, a cyano group, an optionally substituted phenyl group, and a nitrogen-containing heterocyclic group. A positive resist composition comprising an amine (D1) containing at least one kind.

［式（ａ０−１）中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、Ｒ^２は２価の連結基であり、Ｒ^３はその環骨格中に−ＳＯ_２−を含む環式基である。］

[In the formula (a0-1), R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ² is a divalent linking group, and R ³ is It is a cyclic group containing —SO ₂ — in the ring skeleton. ]

  According to a second aspect of the present invention, there is provided a step of forming a resist film on a support using the positive resist composition of the first aspect, a step of exposing the resist film, and an alkali development of the resist film. And a resist pattern forming method including a step of forming a resist pattern.

In the present specification and claims, “aliphatic” is a relative concept with respect to aromatics, and is defined to mean groups, compounds, and the like that do not have aromaticity.
Unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups.
Unless otherwise specified, the “alkylene group” includes linear, branched and cyclic divalent saturated hydrocarbon groups. The same applies to the alkyl group in the alkoxy group.
The “halogenated alkyl group” is a group in which part or all of the hydrogen atoms of the alkyl group are substituted with a halogen atom, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
“Fluorinated alkyl group” or “fluorinated alkylene group” refers to a group in which part or all of the hydrogen atoms of an alkyl group or alkylene group are substituted with fluorine atoms.
“Structural unit” means a monomer unit (monomer unit) constituting a polymer compound (resin, polymer, copolymer).
The “structural unit derived from an acrylate ester” means a structural unit constituted by cleavage of an ethylenic double bond of an acrylate ester.
“Acrylic acid esters” include those in which a hydrogen atom is bonded to the carbon atom at the α-position, and those in which a substituent (atom or group other than a hydrogen atom) is bonded to the carbon atom in the α-position. Include concepts. Examples of the substituent bonded to the α-position carbon atom include an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, and a hydroxyalkyl group. The α-position carbon atom of the acrylate ester is a carbon atom to which a carbonyl group is bonded unless otherwise specified.
“Exposure” is a concept including general irradiation of radiation.

  ADVANTAGE OF THE INVENTION According to this invention, the positive resist composition excellent in lithography performance, such as resolution and MEF, and the resist pattern formation method using this positive resist composition can be provided.

≪Positive resist composition≫
The positive resist composition of the present invention (hereinafter sometimes referred to simply as “resist composition”) is a base component (A) (hereinafter referred to as “component (A)”) whose solubility in an alkaline developer is increased by the action of an acid. ), An acid generator component (B) (hereinafter referred to as (B) component) that generates an acid upon irradiation with radiation, and a nitrogen-containing organic compound (D) (hereinafter referred to as (D) component).
In such a positive resist composition, when radiation is irradiated (exposed), an acid is generated from the component (B), and the solubility of the component (A) in an alkaline developer is increased by the action of the acid. Therefore, in the formation of the resist pattern, when selective exposure is performed on the resist film obtained using the positive resist composition, the solubility of the resist film in the alkaline developer in the exposed portion increases. Since the solubility of the unexposed portion in the alkaline developer does not change, a resist pattern can be formed by performing alkali development.
Here, the “base component” is an organic compound having a film forming ability. As the substrate component, an organic compound having a molecular weight of 500 or more is preferably used. When the molecular weight is 500 or more, the film forming ability is improved, and a nano-level resist pattern is easily formed.
“Organic compounds having a molecular weight of 500 or more” used as the base component are roughly classified into non-polymers and polymers.
As the non-polymer, those having a molecular weight of 500 or more and less than 4000 are usually used. Hereinafter, a non-polymer having a molecular weight of 500 or more and less than 4000 is referred to as a low molecular compound.
As the polymer, those having a molecular weight of 2000 or more are usually used. Hereinafter, a polymer having a molecular weight of 2000 or more is referred to as a polymer compound. In the case of a polymer compound, the “molecular weight” is a polystyrene-reduced mass average molecular weight determined by GPC (gel permeation chromatography). Hereinafter, the polymer compound may be simply referred to as “resin”.

<(A) component>
[Polymer Compound (A1)]
The polymer compound (A1) (hereinafter referred to as the component (A1)) has the structural unit (a0) represented by the general formula (a0-1), and has acid dissociable dissolution inhibition in the structure thereof. Contains groups.
The component (A1) preferably has a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group, in addition to the structural unit (a0).
The component (A1) is a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group in addition to the structural unit (a0) or in addition to the structural units (a0) and (a1). It is preferable to have.
The component (A1) is polar in addition to the structural unit (a0), in addition to the structural units (a0) and (a1), or in addition to the structural units (a0), (a1) and (a2). It is preferable to have a structural unit (a3) derived from an acrylate ester containing a group-containing aliphatic hydrocarbon group.

(Structural unit (a0))
In said formula (a0-1), R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 halogenated alkyl group.
The alkyl group of R is preferably a linear or branched alkyl group, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group. Group, isopentyl group, neopentyl group and the like.
Examples of the halogenated alkyl group for R include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with halogen atoms. Examples of the halogen atom in the halogenated alkyl group include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is particularly preferable.
R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and is most preferably a hydrogen atom or a methyl group in terms of industrial availability.

In formula (a0-1), R ² is a divalent linking group.
Preferred examples of R ² include a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom, and the like.
The hydrocarbon group having “substituent” means that part or all of the hydrogen atoms in the hydrocarbon group are substituted with groups or atoms other than hydrogen atoms.
The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.
An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity. The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.
More specifically, examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, and the like.

The linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, still more preferably 1 to 5, and most preferably 1 to 2.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable. Specifically, a methylene group [—CH ₂ —], an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [ — (CH ₂ ) ₃ —], tetramethylene group [— (CH ₂ ) ₄ —], pentamethylene group [— (CH ₂ ) ₅ —] and the like can be mentioned.
As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ). _{2 -, - C (CH 3} ) (CH 2 CH 3) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as - _{CH (CH 3) CH 2 -} , - CH (CH 3) CH (CH 3) -, - C (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - C (CH 2 An alkylethylene group such as CH ₃ ) ₂ CH ₂ —; an alkyl trimethylene group such as —CH (CH ₃ ) CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) CH ₂ —; —CH (CH ₃ ) CH _{2 CH 2 CH 2 -, -} CH 2 CH (CH 3) CH 2 CH 2 - , etc. And alkyl alkylene group such as an alkyl tetramethylene group. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.
The linear or branched aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

Examples of the aliphatic hydrocarbon group including a ring in the structure include a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), and the cyclic aliphatic hydrocarbon group includes the chain described above. And a group that is bonded to the terminal of the chain-like aliphatic hydrocarbon group or intervenes in the middle of the chain-like aliphatic hydrocarbon group.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic group, a group in which two hydrogen atoms are removed from a monocycloalkane having 3 to 6 carbon atoms is preferable, and examples of the monocycloalkane include cyclopentane and cyclohexane. As the polycyclic group, a group in which two hydrogen atoms are removed from a polycycloalkane having 7 to 12 carbon atoms is preferable. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, tetra And cyclododecane.
The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and most preferably 6 to 12. However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic hydrocarbon group include a hydrogen atom from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Aryl groups such as aryl group, benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc., from which one is removed. The number of carbon atoms of the alkyl chain in the arylalkyl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.
The aromatic hydrocarbon group may have a substituent. For example, a part of carbon atoms constituting the aromatic ring of the aromatic hydrocarbon group may be substituted with a hetero atom, and the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group is substituted with the substituent. May be.
Examples of the former include heteroaryl groups in which some of the carbon atoms constituting the ring of the aryl group are substituted with heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and aromatic hydrocarbons in the arylalkyl groups. Examples include heteroarylalkyl groups in which a part of carbon atoms constituting the ring is substituted with the heteroatom.
Examples of the substituent of the aromatic hydrocarbon group in the latter example include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group as a substituent of the aromatic hydrocarbon group is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. preferable.
The alkoxy group as a substituent of the aromatic hydrocarbon group is preferably an alkoxy group having 1 to 5 carbon atoms, and is a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, tert- A butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent of the aromatic hydrocarbon group include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

The hetero atom in the “divalent linking group containing a hetero atom” is an atom other than a carbon atom and a hydrogen atom, and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom.
As the divalent linking group containing a hetero atom, specifically, —O—, —C (═O) —, —C (═O) —O—, carbonate bond (—O—C (═O) — _{O -), - S -,} - S (= O) 2 -, - S (= O) 2 -O -, - NH -, - NR 04 - (R 04 is an alkyl group, with a substituent such as an acyl group And a divalent non-hydrocarbon group containing a hetero atom such as —NH—C (═O) — and ═N—. Moreover, the combination etc. of these "divalent non-hydrocarbon groups containing a hetero atom" and a divalent hydrocarbon group are mentioned. Examples of the divalent hydrocarbon group include the same hydrocarbon groups that may have a substituent as described above, and a linear or branched aliphatic hydrocarbon group is preferable.

R ² may or may not have an acid dissociable site in its structure. The “acid-dissociable site” refers to a site in the organic group that is dissociated by the action of an acid generated by exposure. When R ² has an acid dissociable portion, it is preferable that it preferably has an acid dissociable portion having a tertiary carbon atom.

In the present invention, the divalent linking group for R ² is preferably an alkylene group, a divalent aliphatic cyclic group or a divalent linking group containing a hetero atom. Among these, an alkylene group is particularly preferable.
When R ² is an alkylene group, the alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms. It is most preferable that it is number 1-3. Specific examples include the same linear alkylene groups and branched alkylene groups as mentioned above.
When R ² is a divalent aliphatic cyclic group, the aliphatic cyclic group is the same as the cyclic aliphatic hydrocarbon group mentioned in the above “aliphatic hydrocarbon group containing a ring in the structure”. Can be mentioned.
The aliphatic cyclic group is particularly preferably a group in which two or more hydrogen atoms have been removed from cyclopentane, cyclohexane, norbornane, isobornane, adamantane, tricyclodecane or tetracyclododecane.

When R ² is a divalent linking group containing a hetero atom, preferred examples of the linking group include —O—, —C (═O) —O—, —C (═O) —, —O—C. (═O) —O—, —C (═O) —NH—, —NH—, —NR ⁰⁴ — (R ⁰⁴ is a substituent such as an alkyl group or an acyl group), —S—, —S. (═O) ₂ —, —S (═O) ₂ —O—, a group represented by the formula —A—O—B—, and a formula — [A—C (═O) —O] _m —B—. And the group represented. Here, A and B are each independently a divalent hydrocarbon group which may have a substituent, and m is an integer of 0 to 3.
When R ² is —NR ⁰⁴ —, R ⁰⁴ is a substituent such as an alkyl group or an acyl group. The substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 5 carbon atoms.
In —A—O—B— or — [A—C (═O) —O] _m —B—, A and B are each independently a divalent hydrocarbon which may have a substituent. It is a group.
Examples of the divalent hydrocarbon group which may have a substituent in A and B are the same as those described above as the “divalent hydrocarbon group which may have a substituent” in R ² . Can be mentioned.
As A, a linear aliphatic hydrocarbon group is preferable, a linear alkylene group is more preferable, a linear alkylene group having 1 to 5 carbon atoms is more preferable, and a methylene group or an ethylene group is particularly preferable. .
B is preferably a linear or branched aliphatic hydrocarbon group, more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.
In the group represented by the formula — [A—C (═O) —O] _m —B—, m is an integer of 0 to 3, preferably an integer of 0 to 2, and 0 or 1 Is more preferable and 1 is most preferable.

In formula (a0-1), R ³ is a cyclic group containing —SO ₂ — in the ring skeleton.
The cyclic group in R ³ represents a cyclic group containing a ring containing —SO ₂ — in the ring skeleton, and the ring is counted as the first ring. When the group has another ring structure, it is called a polycyclic group regardless of the structure. The cyclic group for R ³ may be a monocyclic group or a polycyclic group.
R ³ is particularly preferably a cyclic group containing —O—SO ₂ — in the ring skeleton.
The cyclic group for R ³ preferably has 3 to 30 carbon atoms, preferably 4 to 20 carbon atoms, more preferably 4 to 15 carbon atoms, and particularly preferably 4 to 12 carbon atoms. However, the carbon number is the number of carbon atoms constituting the ring skeleton, and does not include the carbon number in the substituent.
The cyclic group for R ³ may be an aliphatic cyclic group or an aromatic cyclic group. An aliphatic cyclic group is preferable.
As the aliphatic cyclic group for R ^3, a carbon atom constituting a ring skeleton of the cyclic aliphatic hydrocarbon group mentioned above is partially substituted with —SO ₂ — or —O—SO ₂ —. Is mentioned.
More specifically, for example, the monocyclic group includes a group obtained by removing one hydrogen atom from a monocycloalkane in which —CH ₂ — constituting the ring skeleton is substituted with —SO ₂ —, and the ring And a group in which one hydrogen atom is removed from a monocycloalkane in which —CH ₂ —CH ₂ — constituting R ₁ is substituted with —O—SO ₂ —. The polycyclic group includes one hydrogen atom from a polycycloalkane (bicycloalkane, tricycloalkane, tetracycloalkane, etc.) in which —CH ₂ — constituting the ring skeleton is substituted with —SO ₂ —. And a group obtained by removing one hydrogen atom from a polycycloalkane in which —CH ₂ —CH ₂ — constituting the ring is substituted with —O—SO ₂ —.

The cyclic group for R ³ may have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), —COOR ″, —OC (═O) R ″, a hydroxyalkyl group, a cyano group, and the like. Is mentioned.
The alkyl group as the substituent is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, and a hexyl group. Among these, a methyl group or an ethyl group is preferable, and a methyl group is particularly preferable.
The alkoxy group as the substituent is preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group is preferably linear or branched. Specifically, the group couple | bonded with the oxygen atom (-O-) to the alkyl group quoted as the alkyl group as the said substituent is mentioned.
Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group for the substituent include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.
Examples of the halogenated alkyl group as the substituent include groups in which part or all of the hydrogen atoms of the alkyl group mentioned as the alkyl group as the substituent are substituted with the halogen atom. As the halogenated alkyl group, a fluorinated alkyl group is preferable, and a perfluoroalkyl group is particularly preferable.
R ″ in —COOR ″ and —OC (═O) R ″ is a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 15 carbon atoms.
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably a methyl group or an ethyl group. preferable.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom Or a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorinated alkyl group More specifically, one or more hydrogen atoms are removed from a monocycloalkane such as cyclopentane or cyclohexane, or a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Groups and the like.
The hydroxyalkyl group as the substituent is preferably one having 1 to 6 carbon atoms. Specifically, at least one of the hydrogen atoms of the alkyl group mentioned as the alkyl group as the substituent is substituted with a hydroxyl group. Group.
More specifically, examples of R ³ include groups represented by the following general formulas (3-1) to (3-4).

［式中、Ａ’は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり、ａは０〜２の整数であり、Ｒ^６はアルキル基、アルコキシ基、ハロゲン化アルキル基、水酸基、−ＣＯＯＲ”、−ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基またはシアノ基であり、Ｒ”は水素原子またはアルキル基である。］

[Wherein, A ′ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, a is an integer of 0 to 2, and R ⁶ is an alkyl group. An alkoxy group, a halogenated alkyl group, a hydroxyl group, —COOR ″, —OC (═O) R ″, a hydroxyalkyl group or a cyano group, and R ″ is a hydrogen atom or an alkyl group.]

In the general formulas (3-1) to (3-4), A ′ represents an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (—O—) or a sulfur atom (—S—), An oxygen atom or a sulfur atom.
The alkylene group having 1 to 5 carbon atoms in A ′ is preferably a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group.
When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include a group in which —O— or —S— is interposed between the terminal or carbon atoms of the alkylene group, for example, —O—CH _{2. -, - CH 2 -O-CH} 2 -, - S-CH 2 -, - CH 2 -S-CH 2 - , and the like.
A ′ is preferably an alkylene group having 1 to 5 carbon atoms or —O—, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.
a may be any of 0 to 2, and 0 is most preferable.
When a is 2, the plurality of R ⁶ may be the same or different.
The alkyl group in R ^6, an alkoxy group, a halogenated alkyl group, -COOR ", - OC (= O) R", The hydroxyalkyl groups, respectively, may have the cyclic group in ^{R 3} substituent Examples thereof include the same alkyl groups, alkoxy groups, halogenated alkyl groups, —COOR ″, —OC (═O) R ″, and hydroxyalkyl groups mentioned as groups.
Specific examples of cyclic groups represented by the general formulas (3-1) to (3-4) are shown below. In the formula, “Ac” represents an acetyl group.

Among the above, R ³ is preferably a group represented by the following general formula (3-1), and the chemical formulas (3-1-1), (3-1-18), (3-3-1) It is more preferable to use at least one selected from the group consisting of the group represented by any one of (3-4-1) and the group represented by the chemical formula (3-1-1) is most preferable.

  In the present invention, the structural unit (a0) is particularly preferably a structural unit represented by the following general formula (a0-1-11).

［式中、Ｒは前記と同じであり、Ｒ^０２は直鎖状または分岐鎖状のアルキレン基であり、Ａ’は前記と同じである。］

[Wherein, R is as defined above, R ⁰² is a linear or branched alkylene group, and A ′ is as defined above. ]

The linear or branched alkylene group for R ⁰² preferably has 1 to 10 carbon atoms, more preferably 1 to 8, still more preferably 1 to 5, particularly preferably 1 to 3, 2 is most preferred.
A ′ is preferably a methylene group, an oxygen atom (—O—) or a sulfur atom (—S—).

As the structural unit (a0), one type may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a0) in the component (A1) is the MEF when forming a resist pattern using the positive resist composition containing the component (A1), the shape of the resist pattern to be formed, and the pattern dimensions. In view of excellent in-plane uniformity (CDU), LWR (line width roughness), etc., 1 to 60 mol% is preferable and 5 to 50 mol% is more preferable with respect to all structural units constituting component (A1). 10 to 40 mol% is more preferable, and 15 to 30 mol% is most preferable.

The component (A1) contains an acid dissociable, dissolution inhibiting group in its structure.
The acid dissociable, dissolution inhibiting group has an alkali dissolution inhibiting property that makes the entire component (A1) hardly soluble in an alkali developer before dissociation, and the action of an acid generated from the component (B) during exposure. It is a group having acid dissociation property that dissociates due to. Therefore, when the acid dissociable, dissolution inhibiting group is dissociated from the component (A1), the solubility of the entire component (A1) in the alkaline developer increases.
The acid dissociable, dissolution inhibiting group is a method using the structural unit (a0) containing one corresponding to an acid dissociable, dissolution inhibiting group, or a structural unit containing an acid dissociable, dissolution inhibiting group. It can be introduced by a method of inclusion.
For example, among the structural units listed in the structural unit (a0), the structural units represented by the formulas (3-1-2) and (3-1-17) are the cyclic groups in the structure, It also functions as an acid dissociable, dissolution inhibiting group. Further, R ² is, if having an acid dissociable portion in the structure portion from the acid dissociable portion to the end to fulfill its function as an acid dissociable dissolution inhibiting group. Therefore, when the component (A1) includes, as the structural unit (a0), a component that includes an acid dissociable, dissolution inhibiting group in the structure, the component (A1) includes only the structural unit (a0). It may consist of, and may optionally contain other structural units (for example, structural units (a1) to (a4) described later).
Separately, in the method of containing a structural unit containing an acid dissociable, dissolution inhibiting group, examples of the structural unit containing an acid dissociable, dissolution inhibiting group include the structural unit (a1) described later.
In the present invention, the component (A1) preferably contains a structural unit containing an acid dissociable, dissolution inhibiting group so that an acid dissociable, dissolution inhibiting group is introduced. It is preferable that an acid dissociable, dissolution inhibiting group is introduced by That is, the component (A1) preferably has the structural units (a0) and (a1).
However, the present invention is not limited to this, and a structural unit containing an acid dissociable, dissolution inhibiting group other than the structural units (a0) and (a1) may be contained. For example, among the structural units listed in the structural unit (a2) described later, the structure of the lactone-containing cyclic group is the above formula (a2-1-5) to (a2-1-7), (a2-2-10) to ( In the structural unit represented by a2-2-11), the lactone-containing cyclic group in the structure also functions as an acid dissociable, dissolution inhibiting group. Therefore, when the component (A1) has such a structural unit (a2), the component (A1) may be composed only of the structural units (a0) and (a2), and may optionally be another structural unit. (For example, structural units (a1) and (a3) to (a4) described later) may be included.

(Structural unit (a1))
The structural unit (a1) is a structural unit derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group. Note that a structural unit corresponding to the structural unit (a0) and having an acid dissociable, dissolution inhibiting group in the structure does not correspond to the structural unit (a1).
As the acid dissociable, dissolution inhibiting group in the structural unit (a1), those proposed so far as the acid dissociable, dissolution inhibiting group of the base resin for chemically amplified resist can be used. Generally, a group that forms a cyclic or chain tertiary alkyl ester with a carboxy group in (meth) acrylic acid or the like; an acetal-type acid dissociable, dissolution inhibiting group such as an alkoxyalkyl group is widely known. . The “(meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position.
Here, the “tertiary alkyl ester” is an ester formed by replacing a hydrogen atom of a carboxy group with a chain or cyclic alkyl group, and the carbonyloxy group (—C (O)). A structure in which the tertiary carbon atom of the chain or cyclic alkyl group is bonded to the terminal oxygen atom of -O-). In this tertiary alkyl ester, when an acid acts, a bond is cut between an oxygen atom and a tertiary carbon atom.
The chain or cyclic alkyl group may have a substituent.
Hereinafter, a group that is acid dissociable by constituting a carboxy group and a tertiary alkyl ester is referred to as a “tertiary alkyl ester type acid dissociable, dissolution inhibiting group” for convenience.

Examples of the tertiary alkyl ester type acid dissociable, dissolution inhibiting group include an aliphatic branched acid dissociable, dissolution inhibiting group and an acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group.
Here, “aliphatic branched” means having a branched structure without aromaticity. The structure of the “aliphatic branched acid dissociable, dissolution inhibiting group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
Examples of the aliphatic branched acid dissociable, dissolution inhibiting group include a group represented by -C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ). ^Wherein, R 71 ^{to R 73} each independently represents a linear alkyl group of 1 to 5 carbon atoms. The group represented by —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ) preferably has 4 to 8 carbon atoms, specifically, a tert-butyl group or a 2-methyl-2-butyl group. , 2-methyl-2-pentyl group, 3-methyl-3-pentyl group and the like. A tert-butyl group is particularly preferable.

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The “aliphatic cyclic group” in the structural unit (a1) may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), Etc.
The basic ring structure excluding the substituent of the “aliphatic cyclic group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated. The “aliphatic cyclic group” is preferably a polycyclic group.
Examples of the aliphatic cyclic group include one or more hydrogens from a monocycloalkane which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group. Examples thereof include a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, and tetracycloalkane. More specifically, a group obtained by removing one or more hydrogen atoms from a monocycloalkane such as cyclopentane or cyclohexane or one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. And a group in which a hydrogen atom is removed. Further, a part of the carbon atoms constituting the ring of a group obtained by removing one or more hydrogen atoms from these monocycloalkanes or a group obtained by removing one or more hydrogen atoms from polycycloalkanes are etheric oxygen atoms (- O-) may be substituted.
Examples of the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group include (i) a group having a tertiary carbon atom on the ring skeleton of a monovalent aliphatic cyclic group; (ii) a monovalent A group having an aliphatic cyclic group and a branched alkylene having a tertiary carbon atom bonded thereto; and the like.
(I) Specific examples of the group having a tertiary carbon atom on the ring skeleton of the monovalent aliphatic cyclic group are represented by the following general formulas (1-1) to (1-9). Groups and the like.
(Ii) Specific examples of the group having a monovalent aliphatic cyclic group and a branched alkylene group having a tertiary carbon atom bonded thereto include, for example, the following general formulas (2-1) to (2-1) And the group represented by (2-6).

［式中、Ｒ^１４はアルキル基であり、ｇは０〜８の整数である。］

[Wherein, R ¹⁴ represents an alkyl group, and g represents an integer of 0 to 8. ]

［式中、Ｒ^１５およびＲ^１６は、それぞれ独立してアルキル基である。］

[Wherein, R ¹⁵ and R ¹⁶ each independently represents an alkyl group. ]

The alkyl group for R ¹⁴ is preferably a linear or branched alkyl group.
The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4, and still more preferably 1 or 2. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Among these, a methyl group, an ethyl group, or an n-butyl group is preferable, and a methyl group or an ethyl group is more preferable.
The branched alkyl group preferably has 3 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Specific examples include isopropyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group and the like, and isopropyl group is most preferable.
g is preferably an integer of 0 to 3, more preferably an integer of 1 to 3, and still more preferably 1 or 2.
Examples of the alkyl group for R ^{15 to} R ¹⁶ include the same alkyl groups as those for R ¹⁴ .
In the formulas (1-1) to (1-9) and (2-1) to (2-6), a part of the carbon atoms constituting the ring is substituted with an etheric oxygen atom (—O—). May be.
In formulas (1-1) to (1-9) and (2-1) to (2-6), a hydrogen atom bonded to a carbon atom constituting the ring may be substituted with a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, and a fluorinated alkyl group.

The “acetal-type acid dissociable, dissolution inhibiting group” is generally bonded to an oxygen atom by substituting a hydrogen atom at the terminal of an alkali-soluble group such as a carboxy group or a hydroxyl group. When an acid is generated by exposure, the acid acts to break the bond between the acetal acid dissociable, dissolution inhibiting group and the oxygen atom to which the acetal acid dissociable, dissolution inhibiting group is bonded.
Examples of the acetal type acid dissociable, dissolution inhibiting group include a group represented by the following general formula (p1).

[Wherein, R ¹ 'and R ² ' each independently represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, n represents an integer of 0 to 3, and Y represents an alkyl group having 1 to 5 carbon atoms. Or represents an aliphatic cyclic group. ]

In the formula (p1), n is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.
Examples of the alkyl group for R ¹ ′ and R ² ′ include the same alkyl groups as those described above for R. A methyl group or an ethyl group is preferable, and a methyl group is most preferable.
In the present invention, it is preferable that at least one of R ¹ ′ and R ² ′ is a hydrogen atom. That is, the acid dissociable, dissolution inhibiting group (p1) is preferably a group represented by the following general formula (p1-1).

［式中、Ｒ^１’、ｎ、Ｙは上記と同じである。］

[Wherein R ¹ ′, n and Y are the same as described above. ]

Examples of the alkyl group for Y include the same alkyl groups as those described above for R.
The aliphatic cyclic group for Y can be appropriately selected from monocyclic or polycyclic aliphatic cyclic groups conventionally proposed in a number of ArF resists and the like. For example, the above “aliphatic ring” Examples thereof are the same as the aliphatic cyclic groups mentioned in “Acid-dissociable, dissolution-inhibiting group containing a formula group”.

  Examples of the acetal type acid dissociable, dissolution inhibiting group also include a group represented by the following general formula (p2).

［式中、Ｒ^１７、Ｒ^１８はそれぞれ独立して直鎖状若しくは分岐鎖状のアルキル基または水素原子であり；Ｒ^１９は直鎖状、分岐鎖状若しくは環状のアルキル基である。または、Ｒ^１７およびＲ^１９がそれぞれ独立に直鎖状若しくは分岐鎖状のアルキレン基であって、Ｒ^１７の末端とＲ^１９の末端とが結合して環を形成していてもよい。］

[Wherein, R ¹⁷ and R ¹⁸ each independently represents a linear or branched alkyl group or a hydrogen atom; and R ¹⁹ represents a linear, branched or cyclic alkyl group. Alternatively, R ¹⁷ and R ¹⁹ may be each independently a linear or branched alkylene group, and the end of R ^{17 and} the end of R ¹⁹ may be bonded to form a ring. ]

In R ¹⁷ and R ¹⁸ , the alkyl group preferably has 1 to 15 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group.
In particular, it is preferable that one of R ¹⁷ and R ¹⁸ is a hydrogen atom and the other is a methyl group.
R ¹⁹ is a linear, branched or cyclic alkyl group, preferably having 1 to 15 carbon atoms, and may be any of linear, branched or cyclic.
When R ¹⁹ is linear or branched, it preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When R ¹⁹ is cyclic, it preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, one or more polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group. And the like, in which a hydrogen atom is removed. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
In the above formula ^(p2), a ^{R 17} and ^{R 19} are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 5 carbon ^atoms), and the terminal of ^{R 19} The terminal of R ¹⁷ may be bonded.
In this case, a cyclic group is formed by R ¹⁷ , R ¹⁹ , the oxygen atom to which R ¹⁹ is bonded, and the carbon atom to which the oxygen atom and R ¹⁷ are bonded. The cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring. Specific examples of the cyclic group include a tetrahydropyranyl group and a tetrahydrofuranyl group.

  Specific examples of the acetal type acid dissociable, dissolution inhibiting group include groups represented by the following formulas (p3-1) to (p3-12).

［式中、Ｒ^１３は水素原子またはメチル基であり、ｇは前記と同じである。］

[Wherein, R ¹³ represents a hydrogen atom or a methyl group, and g is the same as defined above. ]

  More specifically, examples of the structural unit (a1) include structural units represented by general formula (a1-0-1) shown below, structural units represented by general formula (a1-0-2) shown below, and the like. .

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり；Ｘ^１は酸解離性溶解抑制基であり；Ｙ^２は２価の連結基であり；Ｘ^２は酸解離性溶解抑制基である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; X ¹ is an acid dissociable, dissolution inhibiting group; Y ² is a divalent linkage. X ² is an acid dissociable, dissolution inhibiting group. ]

In general formula (a1-0-1), R is the same as R in general formula (a0-1).
X ¹ is not particularly limited as long as it is an acid dissociable, dissolution inhibiting group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable, dissolution inhibiting group and acetal type acid dissociable, dissolution inhibiting group. And tertiary alkyl ester type acid dissociable, dissolution inhibiting groups are preferred.
In general formula (a1-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a1-0-1).
Examples of the divalent linking group for Y ² include the same groups as those described above for R ² in formula (a0-1).
Y ² is preferably the aforementioned alkylene group, divalent aliphatic cyclic group or divalent linking group containing a hetero atom. Among these, a divalent linking group containing a hetero atom is preferable, and a linear group having an oxygen atom as a hetero atom, for example, a group containing an ester bond is particularly preferable.
Among them, a group represented by the above-mentioned —A—O—B— or —A—C (═O) —O—B— is preferable, and in particular, — (CH ₂ ) _a —C (═O) —O— ( CH _{2) b} - group is particularly desirable.
a is an integer of 1 to 5, preferably 1 or 2, and most preferably 1.
b is an integer of 1 to 5, preferably 1 or 2, and most preferably 1.
More specifically, examples of the structural unit (a1) include structural units represented by the following general formulas (a1-1) to (a1-4).

［式中、Ｘ’は第３級アルキルエステル型酸解離性溶解抑制基を表し、Ｙは炭素数１〜５の炭素数１〜５のアルキル基、または脂肪族環式基を表し；ｎは０〜３の整数を表し；Ｙ^２は２価の連結基を表し；Ｒは前記と同じであり、Ｒ^１’、Ｒ^２’はそれぞれ独立して水素原子または炭素数１〜５のアルキル基を表す。］

[Wherein, X ′ represents a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, Y represents a C 1-5 alkyl group having 1 to 5 carbon atoms, or an aliphatic cyclic group; Y ² represents a divalent linking group; R is the same as defined above; R ¹ ′ and R ² ′ each independently represent a hydrogen atom or an alkyl group having 1 to 5 carbon atoms; Represents. ]

In the formula, X 'include the same tertiary alkyl ester-type acid dissociable, dissolution inhibiting groups as those described above for X ^{1.
R 1 ', R 2',} n, as the Y, respectively, ^{R 1} in the general formula listed in the description of "acetal-type acid dissociable, dissolution inhibiting group" described above ^{(p1) ', R 2'} , n, Y The same thing is mentioned.
The Y ^2, the same groups as those described above for ^{Y 2} in the general formula (a1-0-2).
Specific examples of the structural units represented by the general formulas (a1-1) to (a1-4) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

As the structural unit (a1), one type may be used alone, or two or more types may be used in combination.
In the present invention, the structural unit represented by the following general formula (a1-0-11) as the structural unit (a1), particularly from the point that the lithography properties such as resolution and resist pattern shape are excellent, It is preferable to have at least one selected from the group consisting of a structural unit represented by (a1-0-12) and a structural unit represented by the following general formula (a1-0-2).

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、Ｒ^２１はアルキル基であり、Ｒ^２２は、当該Ｒ^２２が結合した炭素原子と共に脂肪族単環式基を形成する基であり、Ｒ^２３は分岐鎖状のアルキル基であり、Ｒ^２４は、当該Ｒ^２４が結合した炭素原子と共に脂肪族多環式基を形成する基であり、Ｙ^２は２価の連結基であり、Ｘ^２は酸解離性溶解抑制基である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ²¹ is an alkyl group, and R ²² is a carbon to which R ²² is bonded. A group that forms an aliphatic monocyclic group together with an atom, R ²³ is a branched alkyl group, and R ²⁴ is a group that forms an aliphatic polycyclic group together with the carbon atom to which R ²⁴ is bonded. Y ² is a divalent linking group, and X ² is an acid dissociable, dissolution inhibiting group. ]

In each formula, the description of R, Y ² and X ² is the same as described above.
In formula (a1-0-11), examples of the alkyl group for R ²¹ include the same alkyl groups as those described above for R ¹⁴ in formulas (1-1) to (1-9). Group or isopropyl group is preferred.
R ²² is, the aliphatic monocyclic group formed together with the carbon atom to which R ²² is bonded, the same aliphatic cyclic groups as those in the tertiary alkyl ester-type acid dissociable, monocyclic The thing similar to what is a formula group is mentioned. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane is preferably a 3- to 11-membered ring, more preferably a 3- to 8-membered ring, further preferably a 4- to 6-membered ring, and particularly preferably a 5- or 6-membered ring.
In the monocycloalkane, a part of carbon atoms constituting the ring may or may not be substituted with an etheric oxygen atom (—O—).
Moreover, this monocycloalkane may have a C1-C5 alkyl group, a fluorine atom, or a C1-C5 fluorinated alkyl group as a substituent.
Examples of R ²² constituting the aliphatic monocyclic group include a linear alkylene group in which an etheric oxygen atom (—O—) may be interposed between carbon atoms.

Specific examples of the structural unit represented by the formula (a1-0-11) include the formulas (a1-1-16) to (a1-1-23), (a1-1-27), and (a1-1 -31). Among these, the formulas (a1-1-16) to (a1-1-17), (a1-1-20) to (a1-1-23), (a1-1-27), (a1-1-1- The structural unit represented by the following (a1-1-02) including the structural unit represented by 31) is preferable. Moreover, the structural unit represented by the following (a1-1-02 ′) is also preferable.
In each formula, h is preferably 1 or 2.

（式中、Ｒ、Ｒ^２１はそれぞれ前記と同じであり、ｈは１〜３の整数である。）

(Wherein R and R ²¹ are the same as defined above, and h is an integer of 1 to 3)

In the formula (a1-0-12), the branched alkyl group represented by R ^{23 is} the branched alkyl group exemplified for the alkyl group represented by R ^{14 in} the formulas (1-1) to (1-9). Examples thereof are the same as those described above, and an isopropyl group is most preferable.
R ²⁴ is, the aliphatic polycyclic group formed together with the carbon atom to which R ²⁴ is bonded, the same aliphatic cyclic groups as those in the aforementioned tertiary alkyl ester-type acid dissociable, dissolution inhibiting group, a polycyclic The thing similar to what is a formula group is mentioned.
Specific examples of the structural unit represented by the formula (a1-0-12) include structural units represented by the formulas (a1-1-26) to (a1-1-31).

Examples of the structural unit represented by the formula (a1-0-2) include the structural unit represented by the formula (a1-3) or (a1-4), particularly represented by the formula (a1-3). Are preferred.
As the structural unit represented by the formula (a1-0-2), particularly, Y ^{2 in} the formula is represented by the above-mentioned —A—O—B— or —A—C (═O) —O—B—. The group which is a group is preferable.
Preferred examples of the structural unit include a structural unit represented by the following general formula (a1-3-01); a structural unit represented by the following general formula (a1-3-02); 3-03); and the like.

（式中、Ｒ、Ｒ^１４は前記と同じであり、Ｒ^１３は水素原子またはメチル基であり、ａは１〜１０の整数である。）

(In the formula, R and R ¹⁴ are the same as above, R ¹³ is a hydrogen atom or a methyl group, and a is an integer of 1 to 10.)

（式中、Ｒ、Ｒ^１４は前記と同じであり、Ｒ^１３は水素原子またはメチル基であり、ａは１〜１０の整数であり、ｎ’は０〜３の整数である。）

(In the formula, R and R ¹⁴ are the same as above, R ¹³ is a hydrogen atom or a methyl group, a is an integer of 1 to 10, and n ′ is an integer of 0 to 3.)

［式中、Ｒは前記と同じであり、Ｙ^２’およびＹ^２”はそれぞれ独立して２価の連結基であり、Ｘ’は酸解離性溶解抑制基であり、ｎは０〜３の整数である。］

[Wherein, R is the same as defined above, Y ² ′ and Y ² ″ each independently represent a divalent linking group, X ′ represents an acid dissociable, dissolution inhibiting group, and n represents 0 to 3] It is an integer.]

In formulas (a1-3-01) to (a1-3-02), R ¹³ is preferably a hydrogen atom.
a is preferably an integer of 1 to 8, more preferably an integer of 1 to 5, and most preferably 1 or 2.
n ′ is preferably 1 or 2, and most preferably 2.
Specific examples of the structural unit represented by the formula (a1-3-01) include structural units represented by the formulas (a1-3-25) to (a1-3-26).
Specific examples of the structural unit represented by the formula (a1-3-02) include structural units represented by the formulas (a1-3-27) to (a1-3-28).

In formula (a1-3-03), examples of the divalent linking group for Y ² ′ and Y ² ″ include the same groups as those described above for Y ² in formula (a1-3).
Y ² ′ is preferably a divalent hydrocarbon group which may have a substituent, more preferably a linear aliphatic hydrocarbon group, and still more preferably a linear alkylene group. Among these, a linear alkylene group having 1 to 5 carbon atoms is preferable, and a methylene group and an ethylene group are most preferable.
Y ² ″ is preferably a divalent hydrocarbon group which may have a substituent, more preferably a linear aliphatic hydrocarbon group, and still more preferably a linear alkylene group. A linear alkylene group of 1 to 5 is preferable, and a methylene group and an ethylene group are most preferable.
Examples of the acid dissociable, dissolution inhibiting group for X ′ include the same groups as described above, and are preferably tertiary alkyl ester type acid dissociable, dissolution inhibiting groups, and (i) the monovalent aliphatic cyclic group described above. A group having a tertiary carbon atom on the ring skeleton of the group is more preferable, and among them, a group represented by the general formula (1-1) is preferable.
n is an integer of 0 to 3, and n is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 1.
As the structural unit represented by the formula (a1-3-03), a structural unit represented by the following general formula (a1-3-03-1) or (a1-3-03-2) is preferable. Among these, the structural unit represented by the formula (a1-3-03-1) is preferable, and the structural units represented by the formulas (a1-3-29) to (a1-3-30) are particularly preferable.

［式中、ＲおよびＲ^１４はそれぞれ前記と同じであり、ａは１〜１０の整数であり、ｂは１〜１０の整数であり、ｔは０〜３の整数である。］

[Wherein, R and R ¹⁴ are the same as defined above, a is an integer of 1 to 10, b is an integer of 1 to 10, and t is an integer of 0 to 3, respectively. ]

In the formula (a1-3-03-1) or (a1-3-03-2), a is preferably an integer of 1 to 5, and particularly preferably 1 or 2.
b is preferably an integer of 1 to 5, and 1 or 2 is particularly preferable.
t is preferably an integer of 1 to 3, and 1 or 2 is particularly preferable.

In the present invention, it is particularly preferable that the structural unit (a1) has at least two kinds. Since the lithography properties are improved, the structural unit (a1) contained in the component (A1) is preferably 2 to 4 types, and more preferably 2 or 3 types.
In this case, at least one of the at least two types is a structural unit represented by the general formula (a1-0-11), a structural unit represented by the general formula (a1-0-12), and the It is preferably at least one selected from the group consisting of structural units represented by general formula (a1-0-2).
In this case, the at least two kinds of structural units (a1) are structural units represented by the general formula (a1-0-11), structural units represented by the general formula (a1-0-12), and It may be comprised only from what is selected from the group which consists of a structural unit represented by general formula (a1-0-2), At least 1 sort (s) of these structural units, and a structural unit (a1) which does not correspond to these It may be a combination.

Structural unit represented by general formula (a1-0-11), structural unit represented by general formula (a1-0-12) and structural unit represented by general formula (a1-0-2) As the structural unit (a1) that can be used in combination with at least one selected from the group consisting of: (a1-1) exemplified as specific examples of the general formula (a1-1), 1) to (a1-1-2), structural units represented by the following general formula (a1-0-10) including (a1-1-7) to (a1-1-15), a structural unit represented by a1-2) and a structural unit represented by the general formula (a1-4).
As the structural unit represented by the general formula (a1-0-10), in particular, the following general formula (a1-1-1-) including the formula (a1-1-1) to the formula (a1-1-2). 101) is preferred.

［式中、Ｒは前記と同じであり、Ｒ^２５およびＲ^１１はそれぞれ独立に炭素数１〜５の直鎖状のアルキル基であり、Ｒ^２４は前記と同様である。］

[Wherein, R is the same as defined above, R ²⁵ and R ¹¹ each independently represent a linear alkyl group having 1 to 5 carbon atoms, and R ²⁴ is the same as defined above. ]

  In the component (A1), the proportion of the structural unit (a1) is preferably 10 to 80 mol%, more preferably 20 to 70 mol%, more preferably 25 to 50 mol%, based on all structural units constituting the component (A1). Is more preferable. By setting it to the lower limit value or more, a pattern can be easily obtained when the resist composition is used, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

(Structural unit (a2))
The structural unit (a2) is a structural unit derived from an acrylate ester containing a lactone-containing cyclic group.
Here, the lactone-containing cyclic group refers to a cyclic group containing one ring (lactone ring) containing an —O—C (O) — structure. The lactone ring is counted as the first ring. When only the lactone ring is present, it is called a monocyclic group. When it has another ring structure, it is called a polycyclic group regardless of the structure.
When the component (A1) is used for forming a resist film, the lactone cyclic group of the structural unit (a2) increases the adhesion of the resist film to the substrate or has an affinity for a developer containing water. It is effective in raising.
As the structural unit (a2), any unit can be used without any particular limitation.
Specifically, as the lactone-containing monocyclic group, a group obtained by removing one hydrogen atom from a 4- to 6-membered ring lactone, for example, a group obtained by removing one hydrogen atom from β-propiolactone, or γ-butyrolactone Examples thereof include a group in which one hydrogen atom has been removed, and a group in which one hydrogen atom has been removed from δ-valerolactone. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.
More specifically, examples of the structural unit (a2) include structural units represented by general formulas (a2-1) to (a2-5) shown below.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり；Ｒ’はそれぞれ独立に水素原子、炭素数１〜５のアルキル基、炭素数１〜５のアルコキシ基または−ＣＯＯＲ”であり、Ｒ”は水素原子またはアルキル基であり；Ｒ^２９は単結合または２価の連結基であり、ｓ”は０〜２の整数であり；Ａ”は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり；ｍは０または１である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms; R ′ is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, carbon An alkoxy group of 1 to 5 or —COOR ″, R ″ is a hydrogen atom or an alkyl group; R ²⁹ is a single bond or a divalent linking group, and s ″ is an integer of 0 to 2; A ″ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom; m is 0 or 1. ]

R in the general formulas (a2-1) to (a2-5) is the same as R in the structural unit (a0).
Examples of the alkyl group having 1 to 5 carbon atoms of R ′ include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group.
Examples of the alkoxy group having 1 to 5 carbon atoms of R ′ include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group.
R ′ is preferably a hydrogen atom in view of industrial availability.
The alkyl group in R ″ may be linear, branched or cyclic.
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom Or a group in which one or more hydrogen atoms are removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, which may or may not be substituted with a fluorinated alkyl group Specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane, or a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Etc.
Examples of A ″ include the same as A ′ in the general formula (3-1). A ″ represents an alkylene group having 1 to 5 carbon atoms, an oxygen atom (—O—) or a sulfur atom (— S-) is preferable, and an alkylene group having 1 to 5 carbon atoms or -O- is more preferable. The alkylene group having 1 to 5 carbon atoms is more preferably a methylene group or dimethylmethylene group, and most preferably a methylene group.

R ²⁹ is a single bond or a divalent linking group. Examples of the divalent linking group include the same divalent linking groups as those described above for R ² in the general formula (a0-1) can be given. Among these, an alkylene group, an ester bond (—C (═O) —O—), or a combination thereof is preferable. The alkylene group as the divalent linking group for R ²⁹ is more preferably a linear or branched alkylene group. Specifically, the same as the linear alkylene group and the branched alkylene group mentioned as the aliphatic hydrocarbon group for R ² can be used.
As R ²⁹ , in particular, a single bond or —R ²⁹ ′ —C (═O) —O— [wherein R ²⁹ ′ is a linear or branched alkylene group. ] Is preferable.
The linear or branched alkylene group for R ²⁹ ′ preferably has 1 to 10 carbon atoms, more preferably 1 to 8, more preferably 1 to 5, particularly preferably 1 to 3. ~ 2 is most preferred.
As the linear alkylene group for R ²⁹ ′, a methylene group or an ethylene group is preferable, and a methylene group is particularly preferable. The branched alkylene group for R ²⁹ ′ is preferably an alkylmethylene group or an alkylethylene group, and —CH (CH ₃ ) —, —C (CH ₃ ) ₂ — or —C (CH ₃ ) ₂ CH ₂ — Is particularly preferred.
In formula (a2-1), s ″ is preferably 1 to 2.
Specific examples of the structural units represented by the general formulas (a2-1) to (a2-5) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

In the component (A1), as the structural unit (a2), one type may be used alone, or two or more types may be used in combination.
In the present invention, the component (A1) is at least one selected from the group consisting of structural units represented by any one of the general formulas (a2-1) to (a2-5) as the structural unit (a2). It is preferable that at least one selected from the group consisting of structural units represented by any one of the general formulas (a2-1) to (a2-3) is more preferable. It is particularly preferable to have at least one selected from the group consisting of structural units represented by 1) or (a2-2).

The proportion of the structural unit (a2) in the component (A1) is such that the resist film formed using the positive resist composition containing the component (A1) adheres to a support such as a substrate, and the developer. From the viewpoint of excellent affinity and the like, it is preferably 5 to 70 mol%, more preferably 10 to 65 mol%, more preferably 20 to 65 mol%, based on the total of all the structural units constituting the component (A1). Is more preferable, and 20 to 45 mol% is most preferable. By setting it as the above range, MEF and pattern shape are further improved, and CDU is also improved.
In addition, since the component (A1) is excellent in various lithography properties, the total proportion of the structural unit (a0) and the structural unit (a2) (the structural unit (a0 in the case where the structural unit (a2) is not included). ) Only) is preferably from 1 to 70 mol%, more preferably from 5 to 70 mol%, more preferably from 10 to 65 mol%, based on the total of all structural units constituting the component (A1). It is more preferable that 20 to 65 mol% is most preferable. By setting it as the said range, MEF, pattern shape, and CDU become still more favorable.

(Structural unit (a3))
The structural unit (a3) is a structural unit (a3) derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group.
When the component (A1) has the structural unit (a3), the hydrophilicity of the component (A) is increased, the affinity with the developer is increased, the alkali solubility in the exposed area is improved, and the resolution is improved. Contributes to improvement.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, a fluorinated alcohol group (a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom), and the like. Among these, a hydroxyl group and a carboxy group are preferable.
In the structural unit (a3), the number of polar groups bonded to the aliphatic hydrocarbon group is not particularly limited, but is preferably 1 to 3, and most preferably 1.
The aliphatic hydrocarbon group to which the polar group is bonded may be saturated, unsaturated, or saturated.
More specifically, examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, and the like.

The “linear or branched aliphatic hydrocarbon group” preferably has 1 to 12 carbon atoms, more preferably 1 to 10, more preferably 1 to 8, and further preferably 1 to 6. .
In the linear or branched aliphatic hydrocarbon group, part or all of the hydrogen atoms may be substituted with a substituent other than the polar group. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O). Further, the linear or branched aliphatic hydrocarbon group may have a divalent group containing a hetero atom between carbon atoms. The “divalent group containing a heteroatom” is the “heteroatom represented by the divalent linking group of Y ² in the general formula (a1-0-2) in the description of the structural unit (a1). The same thing as "the bivalent coupling group containing" is mentioned.
When the aliphatic hydrocarbon group is linear or branched, the structural unit (a3) is preferably a structural unit represented by the following general formula (a3-1) or (a3-2).

［式中、Ｒは前記に同じであり、Ｒ^８１は直鎖状または分岐鎖状のアルキレン基であり、Ｒ^８２は、ヘテロ原子を含む２価の基が介在してもよいアルキレン基である。］

[Wherein, R is the same as defined above, R ⁸¹ represents a linear or branched alkylene group, and R ⁸² represents an alkylene group which may be intervened by a divalent group containing a hetero atom. . ]

In formula (a3-1), the alkylene group for R ⁸¹ preferably has 1 to 10 carbon atoms.
In formula (a3-2), the alkylene group for R ⁸² preferably has 2 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and particularly preferably 3 to 6 carbon atoms. In the alkylene group, a divalent group containing a hetero atom may be interposed between carbon atoms. The “divalent group containing a heteroatom” is the “heteroatom represented by the divalent linking group of Y ² in the general formula (a1-0-2) in the description of the structural unit (a1). The same thing as "the bivalent coupling group containing" is mentioned.
R ⁸² preferably includes an oxygen atom as a hetero atom, and more preferably a group represented by the above-mentioned —A—O—B— or —A—C (═O) —O—B—. Among _{them, - (CH 2) a "} -O-C (= O) - (CH 2) b" - [ wherein, a "and b" are each independently from 1 to 3 integers. ] Is preferable.

Examples of the “aliphatic hydrocarbon group including a ring in the structure” include a cyclic aliphatic hydrocarbon group, and whether the cyclic aliphatic hydrocarbon group is bonded to the terminal of the chain aliphatic hydrocarbon group described above. Or the group which intervenes in the middle of a chain-like aliphatic hydrocarbon group etc. are mentioned.
The cyclic aliphatic hydrocarbon group preferably has 3 to 30 carbon atoms. The cyclic aliphatic hydrocarbon group may be polycyclic, monocyclic, or polycyclic.
As the cyclic aliphatic hydrocarbon group, specifically, for example, a resin for a resist composition for ArF excimer laser can be appropriately selected from those proposed. For example, the monocyclic aliphatic hydrocarbon group is preferably a group in which two or more hydrogen atoms are removed from a monocycloalkane having 3 to 20 carbon atoms, and examples of the monocycloalkane include cyclopentane and cyclohexane. . The polycyclic aliphatic hydrocarbon group is preferably a group in which two or more hydrogen atoms are removed from a polycycloalkane having 7 to 30 carbon atoms. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane. , Tricyclodecane, tetracyclododecane and the like.
In the cyclic aliphatic hydrocarbon group, part or all of the hydrogen atoms may be substituted with a substituent other than the polar group. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).
When the aliphatic hydrocarbon group includes a ring in the structure, the structural unit (a3) is a structural unit represented by the following general formula (a3-3), (a3-4) or (a3-5) Is preferred.

［式中、Ｒは前記に同じであり、ｊは１〜３の整数であり、ｋ’は１〜３の整数であり、ｔ’は１〜３の整数であり、ｌ’は１〜５の整数であり、ｓ’は１〜３の整数である。］

[Wherein, R is the same as defined above, j is an integer of 1 to 3, k ′ is an integer of 1 to 3, t ′ is an integer of 1 to 3, and l ′ is 1 to 5] S ′ is an integer of 1 to 3. ]

In formula (a3-3), j is preferably 1 or 2, and more preferably 1. When j is 2, it is preferable that the hydroxyl group is bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group.
In formula (a3-4), k ′ is preferably 1. The cyano group is preferably bonded to the 5th or 6th position of the norbornyl group.
In formula (a3-5), t ′ is preferably 1. l ′ is preferably 1. s ′ is preferably 1.
In formula (a3-5), the oxygen atom (—O—) of the carbonyloxy group is preferably bonded to the 2nd or 3rd position of the norbornane ring. The fluorinated alkyl alcohol group is preferably bonded to the 5th or 6th position of the norbornyl group.

As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a2) in the component (A1) is preferably 1 to 50 mol%, more preferably 1 to 40 mol%, based on all structural units constituting the component (A1). -25 mol% is more preferable, and 3-15 mol% is most preferable.

(Other structural units)
The component (A1) may contain other structural units (hereinafter referred to as the structural unit (a4)) other than the structural units (a1) to (a3) as long as the effects of the present invention are not impaired.
The structural unit (a4) is not particularly limited as long as it is another structural unit not classified into the above structural units (a1) to (a3), and for ArF excimer laser, for KrF excimer laser (preferably ArF excimer) A number of hitherto known materials can be used for resist resins such as lasers.
As the structural unit (a4), for example, a structural unit derived from an acrylate ester containing a non-acid-dissociable aliphatic polycyclic group is preferable. Examples of the polycyclic group include those exemplified in the case of the structural unit (a1), and for ArF excimer laser and KrF excimer laser (preferably for ArF excimer laser). A number of hitherto known materials can be used as the resin component of the resist composition.
In particular, at least one selected from a tricyclodecanyl group, an adamantyl group, a tetracyclododecanyl group, an isobornyl group, and a norbornyl group is preferable in terms of industrial availability. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
Specific examples of the structural unit (a4) include those represented by the following general formulas (a4-1) to (a4-5).

［式中、Ｒは前記と同じである。］

[Wherein, R is the same as defined above. ]

As the structural unit (a4), one type may be used alone, or two or more types may be used in combination.
When the structural unit (a4) is contained in the component (A1), the proportion of the structural unit (a4) is preferably 1 to 30 mol% with respect to the total of all the structural units constituting the component (A1). 20 mol% is more preferable.

The component (A1) is preferably a copolymer having the structural unit (a0) and at least one selected from the group consisting of the structural units (a1) to (a3).
Examples of the copolymer include a copolymer composed of the structural units (a0) and (a1), a copolymer composed of the structural units (a0) and (a2), and a structural unit (a0) and (a3). Copolymer, copolymer composed of structural units (a0), (a1) and (a2), copolymer composed of structural units (a0), (a1) and (a3), structural units (a0), (a1 ), (A2) and (a3). However, when the copolymer does not include the structural unit (a1), the structural unit (a0) preferably includes an acid dissociable, dissolution inhibiting group.
Among these, the component (A1) is preferably a copolymer having the structural units (a0), (a1) and (a3), and is a copolymer comprising the structural units (a0), (a1) and (a3). Or a copolymer comprising the structural units (a0), (a1), (a2) and (a3) is particularly preferred.
Further, when the component (A1) is a copolymer having the structural unit (a1), the copolymer is a structural unit represented by the general formula (a1-0-11) as the structural unit (a1). It is preferable to have at least one selected from the group consisting of a structural unit represented by general formula (a1-0-12) and a structural unit represented by general formula (a1-1-01).
Further, as described above, the copolymer preferably has at least two types as the structural unit (a1), and at least one of the at least two types is represented by the general formula (a1-0-11). ) And a structural unit selected from the group consisting of structural units represented by general formula (a1-0-12), and at least two of them are selected from the above group. More preferably, it is a structural unit.
In the present invention, the component (A1) includes, in particular, those containing five structural units represented by the following general formula (A1-11) and four structural units represented by the following general formula (A1-12). Are preferred.

［式（Ａ１−１１）中、Ｒ、Ｒ^２９、Ｒ^０２、Ａ’、Ｒ^２３、Ｒ^２１、ｈはそれぞれ前記と同じであり、当該式中の複数のＲはそれぞれ同じであっても異なっていてもよい。式（Ａ１−１２）中、Ｒ、Ｒ^０２、Ａ’、ａ、ｂ、Ｒ^１４、Ｒ^２３はそれぞれ前記と同じであり、当該式中の複数のＲはそれぞれ同じであっても異なっていてもよい。］

[In the formula (A1-11), R, R ²⁹ , R ⁰² , A ′, R ²³ , R ²¹ and h are the same as defined above, and the plurality of R in the formula are the same or different. It may be. In formula (A1-12), R, R ⁰² , A ′, a, b, R ¹⁴ and R ²³ are the same as defined above, and the plurality of R in the formula are the same or different. Also good. ]

The weight average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably 2000 to 50000, more preferably 3000 to 30000, and 5000 to 20000. Most preferred. When it is smaller than the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist. When it is larger than the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Further, the dispersity (Mw / Mn) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5. In addition, Mn shows a number average molecular weight.

In the component (A), as the component (A1), one type may be used alone, or two or more types may be used in combination.
The proportion of the component (A1) in the component (A) is preferably 25% by mass or more, more preferably 50% by mass, further preferably 75% by mass, and 100% by mass with respect to the total mass of the component (A). May be. When the ratio is 25% by mass or more, effects such as lithography characteristics are improved.

The component (A1) can be obtained by polymerizing a monomer for deriving each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN).
Further, for the component (A1), in the polymerization, a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination, so that the terminal A —C (CF ₃ ) ₂ —OH group may be introduced into the. As described above, a copolymer into which a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom is introduced has reduced development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective in reducing
As the monomer for deriving each structural unit, a commercially available monomer may be used, or the monomer may be synthesized using a known method.
For example, as a monomer for deriving the structural unit (a0), a compound represented by the following general formula (a0-1-0) (hereinafter referred to as “compound (a0-1-0)”) can be given.

［式中、Ｒ、Ｒ^２〜Ｒ^３はそれぞれ前記と同じである。］

[Wherein, R and R ^{2 to} R ³ are the same as defined above. ]

The manufacturing method of this compound (a0-1-0) is not specifically limited, It can manufacture using a well-known method.
For example, a compound (X-) represented by the following general formula (X-2) is added to a solution of the compound (X-1) represented by the following general formula (X-1) in a reaction solvent in the presence of a base. The compound (a0-1-0) is obtained by adding and reacting 2).
Examples of the base include inorganic bases such as sodium hydride, K ₂ CO ₃ and Cs ₂ CO ₃ ; organic bases such as triethylamine, 4-dimethylaminopyridine (DMAP) and pyridine. Examples of the condensing agent include carbodiimide reagents such as ethyldiisopropylaminocarbodiimide (EDCI) hydrochloride, dicyclohexylcarboimide (DCC), diisopropylcarbodiimide, carbodiimidazole, tetraethylpyrophosphate, benzotriazole-N-hydroxytrisdimethylaminophosphonium hexa Fluorophosphide salt (Bop reagent) and the like.
Moreover, you may use an acid as needed. As the acid, those usually used in dehydration condensation and the like can be used. Specifically, inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p- Organic acids such as toluenesulfonic acid can be mentioned. These may be used alone or in combination of two or more.

［式中、Ｒ、Ｒ^２〜Ｒ^３はそれぞれ前記と同じである。］

[Wherein, R and R ^{2 to} R ³ are the same as defined above. ]

The resist composition of the present invention does not correspond to the component (A1) as the component (A), and is a base material component (hereinafter referred to as “component (A2)”) whose solubility in an alkaline developer is increased by the action of acid. It may contain.
The component (A2) is not particularly limited, and many conventionally known base components for chemically amplified positive resist compositions (for example, for ArF excimer laser, for KrF excimer laser (preferably ArF) A base resin such as for excimer laser) may be arbitrarily selected and used. For example, the base resin for ArF excimer laser includes a resin having the structural unit (a1) as an essential structural unit and optionally further including the structural units (a2) to (a5). Moreover, you may contain the nonpolymer (low molecular compound) whose molecular weight is 500-4000.
(A2) A component may be used individually by 1 type and may be used in combination of 2 or more type.

  In the resist composition of the present invention, the content of the component (A) may be adjusted according to the resist film thickness to be formed.

<(B) component>
(B) It does not specifically limit as a component, What has been proposed as an acid generator for chemical amplification type resists until now can be used. Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, and poly (bissulfonyl) diazomethanes. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.
As the onium salt acid generator, for example, a compound represented by the following general formula (b-1) or (b-2) can be used.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”は、それぞれ独立に、置換基を有していてもよいアリール基またはアルキル基を表し；式（ｂ−１）におけるＲ^１”〜Ｒ^３”のうち、いずれか２つが相互に結合して式中のイオウ原子と共に環を形成してもよく；Ｒ^４”は、置換基を有していても良いアルキル基、ハロゲン化アルキル基、アリール基、またはアルケニル基を表し；Ｒ^１”〜Ｒ^３”のうち少なくとも１つはアリール基を表し、Ｒ^５”〜Ｒ^６”のうち少なくとも１つはアリール基を表す。］

[Wherein, R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group which may have a substituent; R in the formula (b-1) Any one of ¹ ″ to R ³ ″ may be bonded to each other to form a ring together with the sulfur atom in the formula; R ⁴ ″ represents an alkyl group which may have a substituent, a halogen atom; An alkyl group, an aryl group, or an alkenyl group; at least one of R ¹ ″ to R ³ ″ represents an aryl group, and at least one of R ⁵ ″ to R ⁶ ″ represents an aryl group.]

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group which may have a substituent. In addition, any two of R ¹ ″ to R ³ ″ in formula (b-1) may be bonded to each other to form a ring together with the sulfur atom in the formula.
Further, at least one of R ¹ ″ to R ³ ″ represents an aryl group. Of R ¹ ″ to R ³ ″, two or more are preferably aryl groups, and most preferably all of R ¹ ″ to R ³ ″ are aryl groups.

The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and examples thereof include an aryl group having 6 to 20 carbon atoms. The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The aryl group may have a substituent. “Having a substituent” means that part or all of the hydrogen atoms of the aryl group are substituted with a substituent, and examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, An alkoxyalkyloxy group, —O—R ⁵⁰ —CO—O—R ⁵¹ [wherein R ⁵⁰ is an alkylene group, and R ⁵¹ is an acid-dissociable group. ], —O—R ⁵² —CO—O—R ⁵³ [wherein R ⁵² is an alkylene group, and R ⁵³ is a hydrocarbon group having 3 to 30 carbon atoms which may have a substituent. . ] Etc. are mentioned.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, ethyl group, propyl group, n-butyl group, or tert-butyl group. Is most preferred.
As the alkoxy group that may be substituted for the hydrogen atom of the aryl group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, A tert-butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
The halogen atom that may be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.

Examples of the alkoxyalkyloxy group in which the hydrogen atom of the aryl group may be substituted include, for example, —O—C (R ⁴⁷ ) (R ⁴⁸ ) —O—R ^{49 wherein} R ⁴⁷ and R ⁴⁸ are each It is independently a hydrogen atom or a linear or branched alkyl group, R ⁴⁹ is an alkyl group, and R ⁴⁸ and R ⁴⁹ may be bonded to each other to form one ring structure. However, at least one of R ⁴⁷ and R ⁴⁸ is a hydrogen atom. ].
In R ⁴⁷ and R ⁴⁸ , the alkyl group preferably has 1 to 5 carbon atoms, preferably an ethyl group or a methyl group, and most preferably a methyl group.
One of R ⁴⁷ and R ⁴⁸ is preferably a hydrogen atom, the other is preferably a hydrogen atom or a methyl group, and both R ⁴⁷ and R ⁴⁸ are particularly preferably hydrogen atoms.
The alkyl group for R ⁴⁹ preferably has 1 to 15 carbon atoms and may be linear, branched or cyclic.
The linear or branched alkyl group for R ⁴⁹ preferably has 1 to 5 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group. Can be mentioned.
The cyclic alkyl group for R ⁴⁹ preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms.
Specifically, monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, etc., which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group, etc. And a group obtained by removing one or more hydrogen atoms from the polycycloalkane. Examples of the monocycloalkane include cyclopentane and cyclohexane. Examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
R ⁴⁸ and R ⁴⁹ may be bonded to each other to form one ring structure. In this case, a cyclic group is formed by R ⁴⁸ , R ⁴⁹ , the oxygen atom to which R ⁴⁹ is bonded, and the carbon atom to which the oxygen atom and R ⁴⁸ are bonded. The cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring.

In —O—R ⁵⁰ —CO—O—R ⁵¹ in which the hydrogen atom of the aryl group may be substituted, the alkylene group in R ⁵⁰ is preferably a linear or branched alkylene group, and the carbon number thereof 1-5 are preferable. Examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a 1,1-dimethylethylene group.
The acid dissociable group in R ⁵¹ is not particularly limited as long as it is an organic group that can be dissociated by the action of an acid (acid generated from the component (B) at the time of exposure). Examples include the same acid dissociable, dissolution inhibiting groups. Among them, the tertiary alkyl ester type is preferable.
In —O—R ⁵² —CO—O—R ⁵³ in which the hydrogen atom of the aryl group may be substituted, the alkylene group in R ⁵² is R in the above —O—R ⁵⁰ —CO—O—R ^51. The same alkylene group as ⁵⁰ can be mentioned.
The hydrocarbon group for R ⁵³ is not particularly limited, and examples thereof include those similar to X in the formula: XQ ¹ — as a substituent in the description of R ⁴ ″ described later.

The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, linear C1-10, branched or cyclic alkyl group, and the like. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decanyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.
The alkyl group may have a substituent. “Having a substituent” means that part or all of the hydrogen atoms of the alkyl group are substituted with a substituent, and the substituent may be a substituent that the aryl group may have. The thing similar to what was mentioned as group is mentioned.

When any two of R ¹ ″ to R ³ ″ in formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, a 3 to 10 membered ring including the sulfur atom is formed. It is preferable that a 5- to 7-membered ring is formed.
When any two of R ¹ ″ to R ³ ″ in formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, the remaining one may be an aryl group preferable. Examples of the aryl group are the same as the aryl groups of R ¹ ″ to R ³ ″.

Of the cation moiety of the compound represented by formula (b-1), when R ¹ ″ to R ³ ″ are all phenyl groups that may have a substituent, that is, the cation moiety is triphenylmethane. Preferable specific examples in the case of having a skeleton include, for example, cation moieties represented by the following formulas (I-1-1) to (I-1-13).
Moreover, what substituted a part or all of the phenyl group in these cation parts with the naphthyl group which may have a substituent is mentioned as a preferable thing. Of the three phenyl groups, 1 or 2 is preferably substituted with the naphthyl group.

Moreover, among the cation moieties of the compound represented by the formula (b-1), any two of R ¹ ″ to R ³ ″ are bonded to each other to form a ring together with the sulfur atom in the formula. Preferred specific examples of the case include, for example, cation moieties represented by the following formulas (I-2-1) to (I-2-2).
In the following formula (I-2-1), R ⁹ is a phenyl group, a naphthyl group, or an alkyl group having 1 to 5 carbon atoms which may have a substituent.
In the following formula (I-2-2), R ¹⁰ is an optionally substituted phenyl group, naphthyl group, C 1-5 alkyl group, alkoxy group or hydroxyl group.
u is an integer of 1 to 3, and 1 or 2 is most preferable.

［式中、Ｒ^９は、置換基を有していてもよいフェニル基、ナフチル基または炭素数１〜５のアルキル基であり、Ｒ^１０は、置換基を有していてもよいフェニル基、ナフチル基、炭素数１〜５のアルキル基、アルコキシ基または水酸基であり、ｕは１〜３の整数である。］

[Wherein, R ⁹ is a phenyl group optionally having a substituent, a naphthyl group or an alkyl group having 1 to 5 carbon atoms, and R ¹⁰ is a phenyl group optionally having a substituent, A naphthyl group, an alkyl group having 1 to 5 carbon atoms, an alkoxy group or a hydroxyl group, and u is an integer of 1 to 3; ]

R ⁴ ″ represents an alkyl group, a halogenated alkyl group, an aryl group, or an alkenyl group which may have a substituent.
The alkyl group for R ⁴ ″ may be linear, branched or cyclic.
The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.
Examples of the halogenated alkyl group for R ⁴ ″ include groups in which part or all of the hydrogen atoms of the linear, branched, or cyclic alkyl group have been substituted with halogen atoms. A fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
In the halogenated alkyl group, the ratio of the number of halogen atoms to the total number of halogen atoms and hydrogen atoms contained in the halogenated alkyl group (halogenation rate (%)) is preferably 10 to 100%. It is preferable that it is 50 to 100%, and 100% is the most preferable. The higher the halogenation rate, the more preferable the strength of the acid.
The aryl group for R ⁴ ″ is preferably an aryl group having 6 to 20 carbon atoms.
The alkenyl group in R ⁴ ″ is preferably an alkenyl group having 2 to 10 carbon atoms.
In the above R ⁴ ″, “optionally substituted” means one of hydrogen atoms in the linear, branched or cyclic alkyl group, halogenated alkyl group, aryl group, or alkenyl group. It means that part or all may be substituted with a substituent (an atom or group other than a hydrogen atom).
The number of substituents in R ⁴ ″ may be one, or two or more.

Examples of the substituent include a halogen atom, a hetero atom, an alkyl group which may have a substituent, a formula: XQ ^1- [where Q ¹ is a divalent linking group containing an oxygen atom. Yes, X is a C3-C30 hydrocarbon group which may have a substituent. ] Etc. which are represented by these.
Examples of the halogen atom include those similar to those exemplified as the halogen atom in the halogenated alkyl group in R ⁴ ″.
Examples of the hetero atom include an oxygen atom, a nitrogen atom, and a sulfur atom.
Examples of the alkyl group include the same groups as those described above as the “alkyl group optionally having substituent (s)” for R ⁴ ″.

X-Q 1 ^- In the group represented by, Q ¹ represents a divalent linking group containing an oxygen atom.
Q ¹ may contain an atom other than an oxygen atom. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, oxygen atoms, sulfur atoms, and nitrogen atoms.
Examples of the divalent linking group containing an oxygen atom include an oxygen atom (ether bond; —O—), an ester bond (—C (═O) —O—), and an amide bond (—C (═O) —NH. -), A carbonyl group (-C (= O)-), a non-hydrocarbon oxygen atom-containing linking group such as a carbonate bond (-O-C (= O) -O-); the non-hydrocarbon oxygen atom Examples include a combination of a containing linking group and an alkylene group.
Examples of the combination include —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) —O—R ⁹³ —, —C (═O) —O—R. ⁹³ —O—C (═O) — (wherein R ^{91 to} R ⁹³ are each independently an alkylene group).
The alkylene group for R ^{91 to} R ⁹³ is preferably a linear or branched alkylene group, and the alkylene group preferably has 1 to 12 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably 1 to 3 carbon atoms. preferable.
Specific examples of the alkylene group include a methylene group [—CH ₂ —]; —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ) ₂ —, —C ( _{CH 3) (CH 2 CH 3} ) -, - C (CH 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - ; alkylethylene groups such as ethylene group _[-CH 2 CH _2— ]; —CH (CH ₃ ) CH ₂ —, —CH (CH ₃ ) CH (CH ₃ ) —, —C (CH ₃ ) ₂ CH ₂ —, —CH (CH ₂ CH ₃ ) CH ₂ —, Alkylethylene groups such as —C (CH ₂ CH ₃ ) ₂ CH ₂ —; trimethylene group (n-propylene group) [—CH ₂ CH ₂ CH ₂ —]; —CH (CH ₃ ) CH ₂ CH ₂ —, — Alkyl trimethylene groups such as CH ₂ CH (CH ₃ ) CH ₂ —; A tetramethylene group [—CH ₂ CH ₂ CH ₂ CH ₂ —]; an alkyl tetramethylene group such as —CH (CH ₃ ) CH ₂ CH ₂ CH ₂ —, —CH ₂ CH (CH ₃ ) CH ₂ CH ₂ —; A pentamethylene group [—CH ₂ CH ₂ CH ₂ CH ₂ CH ₂ —] and the like can be mentioned.
Q ¹ is preferably a divalent linking group containing an ester bond or an ether bond. Among them, —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) — O—, —C (═O) —O—R ⁹³ — or —C (═O) —O—R ⁹³ —O—C (═O) — is preferred.

In the group represented by XQ ^1- , the hydrocarbon group of X may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.
The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, still more preferably 6 to 15, and most preferably 6 to 12. However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic hydrocarbon group include a hydrogen atom from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Aryl groups such as aryl group, benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc., from which one is removed. The number of carbon atoms of the alkyl chain in the arylalkyl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.
The aromatic hydrocarbon group may have a substituent. For example, a part of carbon atoms constituting the aromatic ring of the aromatic hydrocarbon group may be substituted with a hetero atom, and the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group is substituted with the substituent. May be.
Examples of the former include heteroaryl groups in which some of the carbon atoms constituting the ring of the aryl group are substituted with heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and aromatic hydrocarbons in the arylalkyl groups. Examples include heteroarylalkyl groups in which a part of carbon atoms constituting the ring is substituted with the heteroatom.
Examples of the substituent of the aromatic hydrocarbon group in the latter example include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group as a substituent of the aromatic hydrocarbon group is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. preferable.
The alkoxy group as a substituent of the aromatic hydrocarbon group is preferably an alkoxy group having 1 to 5 carbon atoms, and is a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, tert- A butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent of the aromatic hydrocarbon group include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

The aliphatic hydrocarbon group for X may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic.
In X, the aliphatic hydrocarbon group may have a part of the carbon atoms constituting the aliphatic hydrocarbon group substituted by a substituent containing a hetero atom, and the hydrogen atom constituting the aliphatic hydrocarbon group May be substituted with a substituent containing a hetero atom.
The “heteroatom” in X is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom.
The substituent containing a hetero atom may be composed only of the hetero atom, or may be a group containing a group or atom other than the hetero atom.
Specific examples of the substituent for substituting a part of carbon atoms include, for example, —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O. —, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group, an acyl group, etc.), —S—, —S (═O) ₂ —, — S (= O) _2- O- etc. are mentioned. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent that substitutes part or all of the hydrogen atoms include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and a cyano group.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.

Examples of the aliphatic hydrocarbon group include a linear or branched saturated hydrocarbon group, a linear or branched monovalent unsaturated hydrocarbon group, or a cyclic aliphatic hydrocarbon group (aliphatic ring). Formula group) is preferred.
The linear saturated hydrocarbon group (alkyl group) preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decanyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group and the like.
The branched saturated hydrocarbon group (alkyl group) preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and most preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group, 2-ethylbutyl group, Examples include 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.

As an unsaturated hydrocarbon group, it is preferable that carbon number is 2-10, 2-5 are preferable, 2-4 are preferable, and 3 is especially preferable. Examples of the linear monovalent unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched monovalent unsaturated hydrocarbon group include a 1-methylpropenyl group and a 2-methylpropenyl group.
Among the above, the unsaturated hydrocarbon group is particularly preferably a propenyl group.

The aliphatic cyclic group may be a monocyclic group or a polycyclic group. The number of carbon atoms is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12.
Specifically, for example, a group in which one or more hydrogen atoms are removed from a monocycloalkane; a group in which one or more hydrogen atoms are removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom.
When the aliphatic cyclic group does not contain a substituent containing a hetero atom in the ring structure, the aliphatic cyclic group is preferably a polycyclic group, and has one or more hydrogen atoms from the polycycloalkane. Excluded groups are preferred, and most preferred are groups obtained by removing one or more hydrogen atoms from adamantane.
When the aliphatic cyclic group includes a substituent containing a hetero atom in the ring structure, examples of the substituent containing a hetero atom include —O—, —C (═O) —O—, —S—. , —S (═O) ₂ — and —S (═O) ₂ —O— are preferable. Specific examples of the aliphatic cyclic group include the following formulas (L1) to (L5), (S1) to (S4), and the like.

［式中、Ｑ”は炭素数１〜５のアルキレン基、−Ｏ−、−Ｓ−、−Ｏ−Ｒ^９４−または−Ｓ−Ｒ^９５−であり、Ｒ^９４およびＲ^９５はそれぞれ独立に炭素数１〜５のアルキレン基であり、ｍは０または１の整数である。］

[Wherein, Q ″ is an alkylene group having 1 to 5 carbon atoms, —O—, —S—, —O—R ⁹⁴ — or —S—R ⁹⁵ —, and R ⁹⁴ and R ⁹⁵ are each independently carbon. An alkylene group of 1 to 5 and m is an integer of 0 or 1.]

In the formula, examples of the alkylene group for Q ″, R ⁹⁴ and R ⁹⁵ include the same alkylene groups as those described above for R ^{91 to} R ⁹³ .
In these aliphatic cyclic groups, a part of hydrogen atoms bonded to carbon atoms constituting the ring structure may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, particularly preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.
Examples of the alkoxy group and the halogen atom are the same as those exemplified as the substituent for substituting part or all of the hydrogen atoms.

In the present invention, X is preferably a cyclic group which may have a substituent. The cyclic group may be an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a substituent. It is preferably an aliphatic cyclic group that may be used.
The aromatic hydrocarbon group is preferably a naphthyl group which may have a substituent or a phenyl group which may have a substituent.
As the aliphatic cyclic group which may have a substituent, a polycyclic aliphatic cyclic group which may have a substituent is preferable. The polycyclic aliphatic cyclic group is preferably a group obtained by removing one or more hydrogen atoms from the polycycloalkane, (L2) to (L5), (S3) to (S4), and the like.

In the present invention, ^{R 4} ", ^{X-Q 1} - as a substituent preferably has the case, ^{R 4."} The, ^{X-Q 1} -Y 1 - in the Formula, ^{Q 1} and X are the Y ¹ is an optionally substituted alkylene group having 1 to 4 carbon atoms or an optionally substituted fluorinated alkylene group having 1 to 4 carbon atoms. ] Is preferable.
In the group represented by XQ ¹ -Y ^1- , the alkylene group for Y ¹ includes the same alkylene groups as those described above for Q ¹ having 1 to 4 carbon atoms.
Examples of the fluorinated alkylene group include groups in which part or all of the hydrogen atoms of the alkylene group have been substituted with fluorine atoms.
As Y ^1, _{specifically, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF (CF 2 CF 3) -, _{-C (CF 3) 2 -,} - CF 2 CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF ₃ ) —, —C (CF ₃ ) ₂ CF ₂ —, —CF (CF ₂ CF ₃ ) CF ₂ —, —CF (CF ₂ CF ₂ CF ₃ ) —, —C (CF ₃ ) (CF _{2 CF 3) -; - CHF} -, - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -, - CH (CF 3) CH 2 -, - CH (CF 2 _{CF 3) -, - C (} CH 3) (CF 3) -, - CH 2 CH 2 CH 2 CF 2 -, - C H ₂ CH ₂ CF ₂ CF ₂ —, —CH (CF ₃ ) CH ₂ CH ₂ —, —CH ₂ CH (CF ₃ ) CH ₂ —, —CH (CF ₃ ) CH (CF ₃ ) —, —C ( _{CF 3) 2 CH 2 -;} - CH 2 -, - CH 2 CH 2 -, - CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 -, - CH (CH 2 CH 3) -, - _{C (CH 3) 2 -,} - CH 2 CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 -, - CH (CH 3) CH _{(CH 3) -, - C} (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - CH (CH 2 CH 2 CH 3) -, - C (CH 3) (CH 2 CH ₃ ) — and the like.

Y ¹ is preferably a fluorinated alkylene group, and particularly preferably a fluorinated alkylene group in which the carbon atom bonded to the adjacent sulfur atom is fluorinated. Examples of such fluorinated alkylene _{group, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF 2 CF 2 CF 2 CF 2 _{-, - CF (CF 3)} CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF 3) -, - C (CF 3) 2 CF 2 -, _{-CF (CF 2 CF 3) CF} 2 -; - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -; - CH 2 CH 2 CH 2 CF 2 -, - CH ₂ CH ₂ CF ₂ CF ₂ —, —CH ₂ CF ₂ CF ₂ CF ₂ — and the like can be mentioned.
Of _{these, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, or _CH 2 _CF 2 CF ₂ - is _{preferable, -CF 2 -, - CF 2} CF 2 - or -CF ₂ CF ₂ CF ₂ - is more preferable, -CF ₂ - is particularly preferred.

The alkylene group or fluorinated alkylene group may have a substituent. An alkylene group or a fluorinated alkylene group has a “substituent” means that part or all of the hydrogen atom or fluorine atom in the alkylene group or fluorinated alkylene group is substituted with an atom or group other than a hydrogen atom and a fluorine atom. Means that
Examples of the substituent that the alkylene group or fluorinated alkylene group may have include an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, and a hydroxyl group.

In formula (b-2), R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group. At least one of R ⁵ ″ to R ⁶ ″ represents an aryl group. It is preferable that all of R ⁵ ″ to R ⁶ ″ are aryl groups.
As the aryl group for R ⁵ ″ to R ⁶ ″, the same as the aryl groups for R ¹ ″ to R ³ ″ can be used.
Examples of the alkyl group for R ⁵ ″ to R ⁶ ″ include the same as the alkyl group for R ¹ ″ to R ³ ″.
Among these, it is most preferable that all of R ⁵ ″ to R ⁶ ″ are phenyl groups.
"As ^{R 4} in the formula (b-1)" ^{R 4} in the In the formula (b-2) include the same as.

Specific examples of the onium salt acid generators represented by formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate; bis (4-tert-butylphenyl) iodonium. Trifluoromethane sulfonate or nonafluorobutane sulfonate; triphenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; tri (4-methylphenyl) sulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its Nonafluorobutanesulfonate; dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethanesulfonate, its heptaful Lopropane sulfonate or its nonafluorobutane sulfonate; trifluoromethane sulfonate of monophenyldimethylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; trifluoromethane sulfonate of diphenyl monomethylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate (4-methylphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; (4-methoxyphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; Trifluoromethanesulfonate of tri (4-tert-butyl) phenylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutanesulfonate; trifluoromethanesulfonate of diphenyl (1- (4-methoxy) naphthyl) sulfonium, its heptafluoropropane Sulfonate or its nonafluorobutane sulfonate; trifluoromethane sulfonate of di (1-naphthyl) phenylsulfonium, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1-phenyltetrahydrothiophenium trifluoromethane sulfonate, its heptafluoropropane sulfonate Or nonafluorobutanesulfonate thereof; 1- (4-methylphenyl) ) Tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1- (4-ethoxynaphthalene-1- Yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonaflu 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1-phenyltetrahydrothiopyranium trifluoromethanesulfonate , Its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (4-hydroxyphenyl) tetrahydrothiopyranium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl -4-Hydroxyphenyl) tetrahydrothiopyranium trifluoromethanesulfonate, its heptafluoropropanes Honeto or nonafluorobutanesulfonate; 1- (4-methylphenyl) trifluoromethanesulfonate tetrahydrothiophenium Pila chloride, heptafluoropropane sulfonate or its nonafluorobutane sulfonate, and the like.
In addition, the anion part of these onium salts is substituted with methanesulfonate, n-propanesulfonate, n-butanesulfonate, n-octanesulfonate, 1-adamantanesulfonate, 2-norbornanesulfonate, d-camphor-10-sulfonate, etc. An onium salt substituted with an alkyl sulfonate which may have a phenotype can also be used.
Moreover, the onium salt which replaced the anion part of these onium salts by the anion part represented by either of following formula (b1)-(b8) can also be used.

［式中、ｐは１〜３の整数であり、ｖ０は０〜３の整数であり、ｑ１〜ｑ２はそれぞれ独立に１〜５の整数であり、ｑ３は１〜１２の整数であり、ｒ１〜ｒ２はそれぞれ独立に０〜３の整数であり、ｇは１〜２０の整数であり、ｔ３は１〜３の整数であり、Ｒ^７は置換基である。］

[Wherein, p is an integer of 1 to 3, v0 is an integer of 0 to 3, q1 to q2 are each independently an integer of 1 to 5, q3 is an integer of 1 to 12, and r1 ~r2 are each independently an integer of 0 to 3, g is an integer of 1 to 20, t3 is an integer from 1 to 3, ^{R 7} is a substituent. ]

［式中、ｐ、Ｒ^７、Ｑ”はそれぞれ前記と同じであり、ｎ１〜ｎ５はそれぞれ独立に０または１であり、ｖ１〜ｖ５はそれぞれ独立に０〜３の整数であり、ｗ１〜ｗ５はそれぞれ独立に０〜３の整数である。］

[Wherein, p, R ⁷ and Q ″ are the same as defined above, n1 to n5 are each independently 0 or 1, v1 to v5 are each independently an integer of 0 to 3, w1 to w5 Are each independently an integer of 0 to 3.]

Examples of the substituent for R ⁷ are the same as those described above as the substituent that the aliphatic hydrocarbon group may have and the substituent that the aromatic hydrocarbon group may have in X. Can be mentioned.
Code (r1 and r2, w1 to w5) attached to R ⁷ when is an integer of 2 or more, a plurality of the ^{R 7} groups may be the same, respectively, may be different.
r1 to r2 and w1 to w5 are each preferably an integer of 0 to 2, and more preferably 0 or 1.
v0 to v5 are preferably 0 to 2, and most preferably 0 or 1.
t3 is preferably 1 or 2, and most preferably 1.
q3 is preferably 1 to 5, more preferably 1 to 3, and most preferably 1.

  Moreover, as an onium salt type | system | group acid generator, in the said general formula (b-1) or (b-2), an anion part is represented by the following general formula (b-3) or (b-4). An onium salt-based acid generator replaced with can also be used (the cation moiety is the same as (b-1) or (b-2)).

［式中、Ｘ”は、少なくとも１つの水素原子がフッ素原子で置換された炭素数２〜６のアルキレン基を表し；Ｙ”、Ｚ”は、それぞれ独立に、少なくとも１つの水素原子がフッ素原子で置換された炭素数１〜１０のアルキル基を表す。］

[Wherein X ″ represents an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom; Y ″ and Z ″ each independently represent at least one hydrogen atom as a fluorine atom; Represents an alkyl group having 1 to 10 carbon atoms and substituted with

X ″ is a linear or branched alkylene group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkylene group has 2 to 6 carbon atoms, preferably 3 to 5 carbon atoms, Most preferably, it has 3 carbon atoms.
Y ″ and Z ″ are each independently a linear or branched alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and the alkyl group has 1 to 10 carbon atoms, preferably Has 1 to 7 carbon atoms, more preferably 1 to 3 carbon atoms.
The carbon number of the alkylene group of X ″ or the carbon number of the alkyl group of Y ″ and Z ″ is preferably as small as possible because the solubility in the resist solvent is good within the above carbon number range.
In addition, in the alkylene group of X ″ or the alkyl group of Y ″ and Z ″, as the number of hydrogen atoms substituted with fluorine atoms increases, the strength of the acid increases, and high-energy light or electron beam of 200 nm or less The ratio of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all. Are a perfluoroalkylene group or a perfluoroalkyl group in which a hydrogen atom is substituted with a fluorine atom.

  Moreover, the sulfonium salt which has a cation part represented by the following general formula (b-5) or (b-6) can also be used as an onium salt type | system | group acid generator.

［式中、Ｒ^４１〜Ｒ^４６はそれぞれ独立してアルキル基、アセチル基、アルコキシ基、カルボキシ基、水酸基またはヒドロキシアルキル基であり；ｎ_１〜ｎ_５はそれぞれ独立して０〜３の整数であり、ｎ_６は０〜２の整数である。］

[Wherein R ^{41 to} R ⁴⁶ are each independently an alkyl group, acetyl group, alkoxy group, carboxy group, hydroxyl group or hydroxyalkyl group; n _{1 to} n ₅ are each independently an integer of 0 to 3; There, _{n 6} is an integer of 0-2. ]

In R ^{41 to} R ⁴⁶ , the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, more preferably a linear or branched alkyl group, and a methyl group, an ethyl group, a propyl group, an isopropyl group, n A butyl group or a tert-butyl group is particularly preferable.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a linear or branched alkoxy group, and particularly preferably a methoxy group or an ethoxy group.
The hydroxyalkyl group is preferably a group in which one or more hydrogen atoms in the alkyl group are substituted with a hydroxy group, and examples thereof include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.
When the symbols n _{1 to} n ₆ attached to R ^{41 to} R ⁴⁶ are integers of 2 or more, the plurality of R ^{41 to} R ⁴⁶ may be the same or different.
n ₁ is preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.
n ₂ and n ₃ are preferably each independently 0 or 1, more preferably 0.
n ₄ is preferably 0 to 2, more preferably 0 or 1.
n ₅ is preferably 0 or 1, more preferably 0.
n ₆ is preferably 0 or 1, more preferably 1.

The anion part of the sulfonium salt having a cation part represented by the formula (b-5) or (b-6) is not particularly limited, and is the same as the anion part of the onium salt acid generators proposed so far. It may be a thing. Examples of the anion moiety include fluorinated alkyl sulfonate ions such as the anion moiety (R ⁴ ″ SO ₃ ⁻ ) of the onium salt acid generator represented by the general formula (b-1) or (b-2). The anion part represented by the general formula (b-3) or (b-4) may be used.

  In this specification, the oxime sulfonate acid generator is a compound having at least one group represented by the following general formula (B-1), and has a property of generating an acid upon irradiation with radiation. is there. Such oxime sulfonate-based acid generators are frequently used for chemically amplified resist compositions, and can be arbitrarily selected and used.

（式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。）

(In formula (B-1), R ³¹ and R ³² each independently represents an organic group.)

The organic groups of R ³¹ and R ³² are groups containing carbon atoms, and atoms other than carbon atoms (for example, hydrogen atoms, oxygen atoms, nitrogen atoms, sulfur atoms, halogen atoms (fluorine atoms, chlorine atoms, etc.), etc.) You may have.
As the organic group for R ^31, a linear, branched, or cyclic alkyl group or aryl group is preferable. These alkyl groups and aryl groups may have a substituent. There is no restriction | limiting in particular as this substituent, For example, a fluorine atom, a C1-C6 linear, branched or cyclic alkyl group etc. are mentioned. Here, “having a substituent” means that part or all of the hydrogen atoms of the alkyl group or aryl group are substituted with a substituent.
As an alkyl group, C1-C20 is preferable, C1-C10 is more preferable, C1-C8 is more preferable, C1-C6 is especially preferable, and C1-C4 is the most preferable. As the alkyl group, a partially or completely halogenated alkyl group (hereinafter sometimes referred to as a halogenated alkyl group) is particularly preferable. The partially halogenated alkyl group means an alkyl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated alkyl group means that all of the hydrogen atoms are halogen atoms. Means an alkyl group substituted with Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. That is, the halogenated alkyl group is preferably a fluorinated alkyl group.
The aryl group preferably has 4 to 20 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms. As the aryl group, a partially or completely halogenated aryl group is particularly preferable. The partially halogenated aryl group means an aryl group in which a part of hydrogen atoms is substituted with a halogen atom, and the fully halogenated aryl group means that all of the hydrogen atoms are halogen atoms. Means an aryl group substituted with.
R ³¹ is particularly preferably an alkyl group having 1 to 4 carbon atoms having no substituent or a fluorinated alkyl group having 1 to 4 carbon atoms.
As the organic group for R ^32, a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^32, the same alkyl groups and aryl groups as those described above for R ³¹ can be used.
R ³² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

  More preferable examples of the oxime sulfonate-based acid generator include compounds represented by the following general formula (B-2) or (B-3).

［式（Ｂ−２）中、Ｒ^３３は、シアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３４はアリール基である。Ｒ^３５は置換基を有さないアルキル基またはハロゲン化アルキル基である。］

[In Formula (B-2), R ³³ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁴ is an aryl group. R ³⁵ represents an alkyl group having no substituent or a halogenated alkyl group. ]

［式（Ｂ−３）中、Ｒ^３６はシアノ基、置換基を有さないアルキル基またはハロゲン化アルキル基である。Ｒ^３７は２または３価の芳香族炭化水素基である。Ｒ^３８は置換基を有さないアルキル基またはハロゲン化アルキル基である。ｐ”は２または３である。］

[In Formula (B-3), R ³⁶ represents a cyano group, an alkyl group having no substituent, or a halogenated alkyl group. R ³⁷ is a divalent or trivalent aromatic hydrocarbon group. ^R38 is an alkyl group having no substituent or a halogenated alkyl group. p ″ is 2 or 3.]

In the general formula (B-2), the alkyl group or halogenated alkyl group having no substituent of R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and carbon atoms. Numbers 1 to 6 are most preferable.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³³ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred.
As the aryl group of R ³⁴ , one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, or a phenanthryl group. And a heteroaryl group in which a part of carbon atoms constituting the ring of these groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom or a nitrogen atom. Among these, a fluorenyl group is preferable.
The aryl group of R ³⁴ may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.
The alkyl group or halogenated alkyl group having no substituent for R ³⁵ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³⁵ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³⁵ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred is the strength of the acid generated. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

In the general formula (B-3), the alkyl group or halogenated alkyl group having no substituent for R ³⁶ is the same as the alkyl group or halogenated alkyl group having no substituent for R ^33. Is mentioned.
Examples of the divalent or trivalent aromatic hydrocarbon group for R ³⁷ include groups obtained by further removing one or two hydrogen atoms from the aryl group for R ³⁴ .
Examples of the alkyl group or halogenated alkyl group having no substituent of R ³⁸ include the same alkyl groups or halogenated alkyl groups having no substituent as R ³⁵ described above.
p ″ is preferably 2.

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Further, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [chemical formula 18] to [chemical formula 19]), WO2004 / 074242A2 (pages 65 to 85). The oxime sulfonate acid generators disclosed in Examples 1 to 40) of No. 1 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

Among diazomethane acid generators, specific examples of bisalkyl or bisarylsulfonyldiazomethanes include bis (isopropylsulfonyl) diazomethane, bis (p-toluenesulfonyl) diazomethane, bis (1,1-dimethylethylsulfonyl) diazomethane, Examples include bis (cyclohexylsulfonyl) diazomethane, bis (2,4-dimethylphenylsulfonyl) diazomethane, and the like.
Further, diazomethane acid generators disclosed in JP-A-11-035551, JP-A-11-035552, and JP-A-11-035573 can also be suitably used.
Examples of poly (bissulfonyl) diazomethanes include 1,3-bis (phenylsulfonyldiazomethylsulfonyl) propane and 1,4-bis (phenylsulfonyldiazo) disclosed in JP-A-11-322707. Methylsulfonyl) butane, 1,6-bis (phenylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (phenylsulfonyldiazomethylsulfonyl) decane, 1,2-bis (cyclohexylsulfonyldiazomethylsulfonyl) ethane, 1,3 -Bis (cyclohexylsulfonyldiazomethylsulfonyl) propane, 1,6-bis (cyclohexylsulfonyldiazomethylsulfonyl) hexane, 1,10-bis (cyclohexylsulfonyldiazomethylsulfonyl) decane, etc. Door can be.

(B) As a component, these acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.
In the present invention, it is preferable to use an onium salt acid generator having a fluorinated alkyl sulfonate ion as an anion as the component (B).
The content of the component (B) in the positive resist composition of the present invention is preferably 0.5 to 50 parts by mass and more preferably 1 to 40 parts by mass with respect to 100 parts by mass of the component (A). By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

<(D) component>
In the positive resist composition of the present invention, as component (D), an etheric oxygen atom (—O—), an ester group (—O—C (═O) —), a carbonyl group (—C (═O) — ), A cyano group (—CN), an optionally substituted phenyl group, and an amine (D1) (hereinafter referred to as (D1)) selected from the group consisting of a nitrogen-containing heterocyclic group Contains ingredients).

Examples of the substituent in the “optionally substituted phenyl group” of the component (D1) include an alkyl group, a hydroxyalkyl group, an alkoxy group, a thioalkoxy group, a halogen atom, a halogenated alkyl group, and a hydroxyl group. Oxygen atom (= O) and the like.
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and may be a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, or a tert-butyl group. More preferred. Among these, a branched chain is most preferable.
Examples of the hydroxyalkyl group as the substituent include those in which a part of hydrogen atoms of the alkyl group is substituted with a hydroxyl group. In the hydroxyalkyl group, the number of hydroxyl groups is preferably 1 to 3, and most preferably 1. The hydroxyl group is preferably bonded to the end of the alkyl chain, and particularly preferably the alkyl chain is linear.
The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group. Most preferred is an ethoxy group.
Examples of the thioalkoxy group as the substituent include those in which the oxygen atom in the alkoxy group is substituted with a sulfur atom.
Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.
The “optionally substituted phenyl group” is preferably an unsubstituted phenyl group or a phenyl group having an alkyl group as a substituent, and more preferably a 2,6-dialkylphenyl group. The alkyl group is preferably a branched alkyl group, and most preferably an iso-propyl group or a tert-butyl group.

The “nitrogen-containing heterocyclic group” of the component (D1) is a group obtained by removing one or more hydrogen atoms from a nitrogen-containing heterocyclic compound containing a nitrogen atom in the ring skeleton. The nitrogen-containing heterocyclic compound may have a hetero atom (for example, an oxygen atom, a sulfur atom, etc.) other than a carbon atom and a nitrogen atom in its ring skeleton.
The nitrogen-containing heterocyclic compound may be aromatic or aliphatic. Moreover, when aliphatic, it may be saturated or unsaturated. The nitrogen-containing heterocyclic compound may be monocyclic or polycyclic.
The nitrogen-containing heterocyclic compound preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, and still more preferably 5 to 20 carbon atoms.
Specific examples of the monocyclic nitrogen-containing heterocyclic compound include pyrrole, pyridine, imidazole, pyrazole, 1,2,3-triazole, 1,2,4-triazole, pyrimidine, pyrazine, 1,3,5- Examples include triazine, tetrazole, piperidine, piperazine, pyrrolidine, morpholine and the like.
Specific examples of the polycyclic nitrogen-containing heterocyclic compound include quinoline, isoquinoline, indole, pyrrolo [2,3-b] pyridine, indazole, benzimidazole (benzimidazole), benzotriazole, carbazole, acridine, 1, 5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5.4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane, etc. Is mentioned.
The nitrogen-containing heterocyclic compound may have a substituent. Examples of the substituent include a group (I) described later (an etheric oxygen atom, an ester group, a carbonyl group, a cyano group, a phenyl group which may have a substituent, and a nitrogen-containing heterocyclic group). A monovalent hydrocarbon group containing at least one selected from the following :), alkyl groups, hydroxyalkyl groups, alkoxy groups, thioalkoxy groups, halogen atoms, halogenated alkyl groups, hydroxyl groups, oxygen atoms (= O) and the like. It is done. Among these, the alkyl group, hydroxyalkyl group, alkoxy group, thioalkoxy group, halogen atom, and halogenated alkyl group are those listed as the substituents in the above-mentioned “optionally substituted phenyl group”. The same thing is mentioned.
As a substituent which a nitrogen-containing heterocyclic compound has, a nitrogen-containing heterocyclic group, an alkyl group, and an oxygen atom are preferable.
The nitrogen-containing heterocyclic compound having an oxygen atom as a substituent is preferably a compound containing —NH—CO— in the ring, that is, a lactam. Examples of the lactam include γ-lactam and δ-lactam, and γ-lactam is particularly preferable.

As the component (D1), specifically, the structure consists of an etheric oxygen atom, an ester group, a carbonyl group, a cyano group, an optionally substituted phenyl group and a nitrogen-containing heterocyclic group. A compound in which at least one hydrogen atom of ammonia NH ₃ is substituted with a monovalent hydrocarbon group (hereinafter referred to as group (I)) containing at least one selected from the group (hereinafter referred to as compound (D1-1) ))).
The group (I) may contain only one of an etheric oxygen atom, an ester group, a carbonyl group, a cyano group, an optionally substituted phenyl group and a nitrogen-containing heterocyclic group. Two or more kinds may be included. Moreover, the same group may be included two or more.
In the group (I), the hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Further, the aliphatic hydrocarbon group may be saturated or unsaturated, and preferably saturated.
Examples of the group (I) include groups represented by the following general formulas (I-1) to (I-5).

［式中、Ｒ^６１は直鎖状または分岐鎖状のアルキレン基であり、ｎ_１は１〜３の整数であり、Ｒ^６２は置換基を有していてもよいアルキル基であり、Ｒ^６３はアルキレン基であり、Ｌ^１は−Ｏ−Ｃ（＝Ｏ）−、−Ｃ（＝Ｏ）−Ｏ−または−Ｃ（＝Ｏ）−であり、Ｒ^６４は置換基を有していてもよいアルキル基であり、Ｒ^６５は置換基を有していてもよいアルキレン基であり、Ｒ^６６は単結合または置換基を有していてもよいアルキレン基であり、Ｐｈは置換基を有していてもよいフェニル基であり、Ｒ^Ｎは置換基を有していてもよい含窒素複素環式基である。］

[Wherein, R ⁶¹ represents a linear or branched alkylene group, n ₁ represents an integer of ₁ to 3, R ⁶² represents an alkyl group which may have a substituent, and R ⁶³ Is an alkylene group, L ¹ is —O—C (═O) —, —C (═O) —O— or —C (═O) —, and R ⁶⁴ may have a substituent. R ⁶⁵ is an alkylene group which may have a substituent, R ⁶⁶ is an alkylene group which may have a single bond or a substituent, and Ph has a substituent. even if a phenyl group, R ^N is nitrogen-containing heterocyclic group which may have a substituent. ]

In formula (I-1), the number of carbon atoms of the linear or branched alkylene group in R ⁶¹ is preferably 1 to 4, and more preferably 1 to 2. The alkylene group is preferably a linear group, and most preferably an ethylene group.
n ₁ is an integer of 1 to 4, an integer of 1 to 3 are preferred.
When n ₁ is an integer of 2 or more, the plurality of R ⁶¹ in Formula (I-1) may be the same or different.
The alkyl group for R ⁶² may be linear, branched or cyclic, preferably linear or branched, and particularly preferably linear. The carbon number is preferably 1-20, more preferably 1-10, still more preferably 1-6, and most preferably 1-4.
The alkyl group for R ⁶² may have a substituent in the structure thereof.
For example, a part of hydrogen atoms of the alkyl group may be substituted with at least one of a cyano group, a phenyl group which may have a substituent, and a nitrogen-containing heterocyclic group. Specific examples of R ⁶² in this case include a group represented by the formula (I-3) or (I-4). Moreover, you may substitute by other substituents other than those. Examples of the other substituent include a hydroxyl group, a cyano group, a carboxyl group, an alkoxy group, a thioalkoxy group, a halogen atom, and a hydrogen atom.
In addition, when the alkyl group is an alkyl group having 2 or more carbon atoms, an ester group and / or a carbonyl group may be interposed between the carbon atoms. As a specific example of R ^{62 in} such a case, Examples include a group represented by formula (I-2).

In formula (I-2), the alkylene group for R ⁶³ may be linear, branched or cyclic, preferably linear or branched, and particularly preferably linear. 1-10 are preferable, as for the carbon number, 1-8 are more preferable, 1-5 are more preferable, and 1-2 are the most preferable.
Specific examples of the linear alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a pentamethylene group.
Specifically, as the branched alkylene group, —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ) ₂ —, —C (CH ₃ ) (CH ₂ CH _{3) -, - C (CH} 3) (CH 2 CH 2 CH 3) -, - C (CH 2 CH 3) 2 - alkyl groups such _{as; -CH (CH 3) CH 2} -, - CH (CH _{3) CH (CH 3) -} , - C (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - CH (CH 2 CH 3) CH 2 -, - C (CH 2 CH _{3) 2} CH ₂ - alkyl groups such _{as; -CH (CH 3) CH 2} CH 2 -, - CH 2 CH (CH 3) CH 2 - alkyl trimethylene groups such as; -CH _(CH 3) CH _{2 CH 2 CH 2 -, - CH} 2 CH (CH 3) CH 2 CH 2 - , etc. a of Include alkyl alkylene group such Kill tetramethylene group. The alkyl group in the alkyl alkylene group is preferably a linear alkyl group having 1 to 5 carbon atoms.

In formula (I-2), L ¹ is —O—C (═O) —, —C (═O) —O— or —C (═O) —, and in particular —O—C (═O). -Is preferred.
The alkyl group for R ⁶⁴ may be linear, branched or cyclic, preferably linear or branched, and particularly preferably linear. 1-10 are preferable, as for the carbon number, 1-8 are more preferable, 1-5 are more preferable, and 1-2 are the most preferable.
The alkyl group for R ⁶⁴ may have a substituent in the structure thereof.
For example, a part of hydrogen atoms of the alkyl group may be substituted with at least one of a cyano group, a phenyl group which may have a substituent, and a nitrogen-containing heterocyclic group. Specific examples of R ⁶⁴ in this case include a group represented by formula (I-3) or (I-4). Moreover, you may substitute by other substituents other than those. Examples of the other substituent include a hydroxyl group.
Further, when the alkyl group is an alkyl group having 2 or more carbon atoms, any one or more of an etheric oxygen atom, an ester group and a carbonyl group may be interposed between the carbon atoms. Specific examples of R ⁶⁴ in this case include a group represented by the formula (I-1).

In formula (I-3), the alkylene group for R ⁶⁵ may be linear, branched or cyclic, preferably linear or branched, and particularly preferably linear. 1-10 are preferable, as for the carbon number, 1-8 are more preferable, 1-5 are more preferable, and 1-2 are the most preferable.
The alkylene group for R ⁶⁵ may have a substituent in the structure thereof.
For example, a part of hydrogen atoms of the alkylene group may be substituted with at least one of a cyano group, a phenyl group which may have a substituent, and a nitrogen-containing heterocyclic group, and others It may be substituted with other substituents. Examples of the other substituent include a hydroxyl group.
When the alkylene group is an alkylene group having 2 or more carbon atoms, any one or more of an etheric oxygen atom, an ester group and a carbonyl group may be interposed between the carbon atoms. Specific examples of R ^{65 in} such a case include a group obtained by removing one hydrogen atom from R ^{62 of the} group represented by the formula (I-1), and a group represented by the formula (I-2). Group obtained by removing one hydrogen atom from R ^{64 in the} formula.
The alkylene group for R ⁶⁵ is preferably an unsubstituted alkylene group.

In formula (I-4), examples of the alkylene group for R ⁶⁶ include the same groups as ^those described above for R ⁶⁵ .
Most preferably, R ⁶⁶ is a single bond.
In Ph, examples of the substituent that the phenyl group may have include the same substituents as those described above as the substituent in the “phenyl group that may have a substituent”.
Wherein ^(I-5), as the alkylene group for ^{R 66,} are the same as those for ^{R 66} in the formula (I-4).
^Examples of the nitrogen-containing heterocyclic group in RN include the same as those mentioned as the “nitrogen-containing heterocyclic group” of the component (D1). The R ^N, particularly preferably pyridyl group which may have a substituent group, 4-pyridyl group is particularly preferred.

The number of groups (I) (number of groups (I) substituting the hydrogen atom of ammonia NH ₃ ) possessed by the compound (D1-1) may be any of 1 to 3.
The compound (D1-1) may have an organic group other than the group (I). As this organic group, the monovalent | monohydric aliphatic hydrocarbon group (henceforth group (II)) which may have substituents other than the said group (I) is mentioned, for example.
The monovalent aliphatic hydrocarbon group may be saturated (alkyl group) or unsaturated. In addition, each of the aliphatic hydrocarbon groups may be linear, branched or cyclic. In the case of an unsaturated hydrocarbon group, a linear or branched chain is preferable.
The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms, and still more preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decanyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group, hexadecyl group, isohexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, icosyl group, heicosyl group, docosyl group and the like.
The branched alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 15 carbon atoms, and still more preferably 3 to 10 carbon atoms. Specifically, for example, 1-methylethyl group (iso-propyl group), 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, 1-ethylbutyl group 2-ethylbutyl group, tert-butyl group, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like.
The cyclic alkyl group may be a monocyclic group or a polycyclic group. The number of carbon atoms is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12. Specific examples include a group in which one hydrogen atom has been removed from a monocycloalkane; a group in which one hydrogen atom has been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, and tetracycloalkane. . More specifically, a group obtained by removing one hydrogen atom from a monocycloalkane such as cyclopentane or cyclohexane; one hydrogen atom from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane or tetracyclododecane. And the like except for.
2-5 are preferable, as for carbon number of an unsaturated hydrocarbon group, 2-4 are more preferable, and 3 is especially preferable. Examples of the linear monovalent unsaturated hydrocarbon group include a vinyl group, a propenyl group (allyl group), and a butynyl group. Examples of the branched monovalent unsaturated hydrocarbon group include a 1-methylpropenyl group and a 2-methylpropenyl group. Among the above, the unsaturated hydrocarbon group is particularly preferably a propenyl group.

In the group (II), examples of the substituent other than the group (I) that the monovalent aliphatic hydrocarbon group may have include a hydroxy group.
As the group (II), an alkyl group and a hydroxyalkyl group are particularly preferable.
The alkyl group may be linear, branched or cyclic as described above, and is preferably linear or branched.
Examples of the hydroxyalkyl group include those in which a part of hydrogen atoms of the alkyl group is substituted with a hydroxyl group. In the hydroxyalkyl group, the number of hydroxyl groups is preferably 1 to 3, and most preferably 1. The hydroxyl group is preferably bonded to the end of the alkyl chain, and particularly preferably the alkyl chain is linear.

When the number of organic groups (the total number of groups (I) and groups (II)) of compound (D1-1) is 2 or 3, 2 or 3 of them are bonded to each other to form a ring You may do it.
The ring formed in this case is a nitrogen-containing heterocyclic group containing a nitrogen atom in its ring structure, and specific examples thereof include the “nitrogen-containing heterocyclic group” possessed by the component (D1). The same thing is mentioned.

The compound (D1-1) may be any of primary amines such as aniline, secondary amines, and tertiary amines, preferably secondary amines or tertiary amines, and tertiary amines. Is particularly preferred.
In the case of primary amines, the substituent replacing one of the NH ₃ hydrogen atoms is the group (I). The group (I) is preferably an optionally substituted phenyl group or a nitrogen-containing heterocyclic group, more preferably a phenyl group having a substituent, and a branched alkyl group as the substituent. Particularly preferred are phenyl groups having
In the case of a secondary amine, at least one of the substituents replacing two hydrogen atoms of NH ₃ is the group (I). The remaining one may be the group (I) or the group (II).
In the case of a tertiary amine, at least one of the substituents replacing three hydrogen atoms of NH ₃ is the group (I). The remaining two may be the group (I) or the group (II).
As the compound (D1-1), a tertiary amine represented by the following general formula (d1-1) is particularly preferable.

［式中、Ｒ^７〜Ｒ^９は、それぞれ独立して、置換基を有していてもよい炭化水素基であり、Ｒ^７〜Ｒ^９のうちの少なくとも１つは、その構造中に、エーテル性酸素原子、エステル基、カルボニル基、シアノ基、置換基を有していてもよいフェニル基、および含窒素複素環式基からなる群から選択される少なくとも１種を含み、Ｒ^７〜Ｒ^９のうちのいずれか２つが相互に結合して、式中の窒素原子とともに環を形成していてもよい。］

[Wherein, R ^{7 to} R ⁹ are each independently a hydrocarbon group which may have a substituent, and at least one of R ^{7 to} R ⁹ is an ether in its structure. An oxygen atom, an ester group, a carbonyl group, a cyano group, a phenyl group which may have a substituent, and at least one selected from the group consisting of a nitrogen-containing heterocyclic group, and R ^{7 to} R ⁹ Any two of them may be bonded to each other to form a ring together with the nitrogen atom in the formula. ]

In formula (d1-1), in R ^{7 to} R ⁹ , among the hydrocarbon groups which may have a substituent, the structure includes an etheric oxygen atom, an ester group, a carbonyl group, a cyano group, a substituted group. As the hydrocarbon group containing at least one selected from the group consisting of a phenyl group which may have a group and a nitrogen-containing heterocyclic group (hereinafter referred to as group (I ′)), the group ( The thing similar to what was mentioned by I) is mentioned. In particular, the groups represented by the general formulas (I-1) to (I-5) are preferable.
Of R ^{7 to} R ^9, the number of the group (I ′) may be one, two, or three.
One or two of R ^{7 to} R ⁹ may be “an optionally substituted hydrocarbon group” that does not correspond to the group (I ′). As this hydrocarbon group, the thing similar to what was mentioned as said group (II) is mentioned, for example.
In formula (d1-1), any two of R ^{7 to} R ⁹ may be bonded to each other to form a ring together with the nitrogen atom in the formula. As the ring formed in this case, for example, among the nitrogen-containing heterocyclic compounds mentioned in the “nitrogen-containing heterocyclic group” of the component (D1), those containing —NH— in the ring structure A group obtained by removing a hydrogen atom in -NH- from (NH-containing heterocyclic compound) can be mentioned.
When the remaining one of R ^{7 to} R ⁹ is not a group (I ′), the NH nitrogen-containing heterocyclic compound has an etheric oxygen atom, an ester group, a carbonyl group, a cyano group, And at least one selected from the group consisting of optionally substituted phenyl groups. Among these, it is preferable that an etheric oxygen atom or a carbonyl group is included. As the NH nitrogen-containing heterocyclic compound, an NH nitrogen-containing heterocyclic compound in which a part of carbon atoms constituting the ring is substituted with an oxygen atom (—O—), an oxygen atom ( NH-containing heterocyclic compounds to which ═O) are bonded, and the like, and morphine and γ-lactam are particularly preferable.
Preferred examples of the compound (D1-1) include those represented by the following general formulas (d1-1-1) to (d1-1-6).

［式中、Ｒ^６１、Ｒ^６２、ｎ_１、Ｒ^６３、Ｒ^６４、Ｒ^６５、Ｒ^６６およびＰｈはそれぞれ前記と同じであり、Ｒ^６７はアルキル基またはヒドロキシアルキル基であり、Ｒ^６８は水素原子または有機基である。］

[Wherein R ⁶¹ , R ⁶² , n ₁ , R ⁶³ , R ⁶⁴ , R ⁶⁵ , R ⁶⁶ and Ph are the same as defined above, R ⁶⁷ is an alkyl group or a hydroxyalkyl group, and R ⁶⁸ is hydrogen. An atom or an organic group. ]

In formulas (d1-1-1) to (d1-1-5), R ⁶¹ , R ⁶² , n ₁ , R ⁶³ , R ⁶⁴ , R ⁶⁵ , R ⁶⁶ and Ph are the same as ^those in formula (I-1) to The same as R ⁶¹ , R ⁶² , n ₁ , R ⁶³ , R ⁶⁴ , R ⁶⁵ , R ⁶⁶ and Ph in (I-4).
Among these, R ⁶¹ in formulas (d1-1-1) to (d1-1-2) is preferably a linear alkylene group, and particularly preferably an ethylene group.
n ₁ is preferably an integer of 2 to 4, and most preferably 2.
R ⁶² is preferably a linear alkyl group or a linear hydroxyalkyl group, and more preferably a hydrogen atom, a methyl group or a hydroxymethyl group.
In formulas (d1-1-1) to (d1-1-2), preferred specific examples of the group represented by — (R ⁶¹ O) n ₁ -R ⁶² include a 2-methoxymethoxyethyl group, 2- (2-methoxyethoxy) ethyl group, 2- (2-methoxyethoxymethoxy) ethyl group, 2- (1-methoxyethoxy) ethyl group, 2- (1-ethoxyethoxy) ethyl group, 2- (1-ethoxypropoxy) ) Ethyl group, 2- {2- (2-hydroxyethoxy) ethoxy} ethyl group and the like.

R ^{63 in} formulas (d1-1-3) to (d1-1-4) is preferably a linear alkylene group, and particularly preferably an ethylene group.
R ⁶⁴ is preferably a linear alkyl group which may have an etheric oxygen atom, and the alkyl group preferably has 1 to 10 carbon atoms. If the alkyl group has an etheric oxygen atom, and specific examples thereof include the ^- it includes the same ^{_{(R 61 O) n 1 -R}} 62.
R ⁶⁵ in formula (d1-1-4) is preferably a linear alkylene group, preferably an alkylene group having 1 to 4 carbon atoms, and particularly preferably an ethylene group.
In formula (d1-1-5), R ⁶⁵ is most preferably a single bond.
^Examples of the alkyl group and hydroxyalkyl group in R ⁶⁷ are the same as the alkyl group and hydroxyalkyl group mentioned in the description of the group (II).
In formula (d1-1-6), examples of the organic group for R ⁶⁸ include the group (I) and the group (II). Of these, the group (I) is preferably a group represented by the formula (I-5), particularly preferably R ⁶⁶ is a single bond. As the group (II), an alkyl group is preferable, and a branched or cyclic alkyl group is particularly preferable.

In addition to the compound (D1-1), examples of the compound preferably used as the component (D1) include cyclic amines.
Examples of the cyclic amine include the nitrogen-containing heterocyclic compounds mentioned in the description of the nitrogen-containing heterocyclic group. As the cyclic amine, those having —NH— and / or an unsaturated bond (C═N, C═C, N═N, etc.) in the ring skeleton are particularly preferable. Specific examples of such cyclic amines include pyrrole, imidazole, pyrazole, 1,2,3-triazole, 1,2,4-triazole, indole, tetrazole, pyridine, piperidine, piperazine, pyrrolidine, morpholine, indole, and indazole. , Benzimidazole (benzimidazole), benzotriazole, carbazole, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5.4.0] -7-undecene, and the like. .
These cyclic amines may have a substituent. “It may have a substituent” means that a part of a hydrogen atom bonded to a carbon atom and a nitrogen atom bonded to a carbon atom in a cyclic amine is a substituent (a group or atom other than a hydrogen atom). It means that it is replaced with.
Examples of the substituent include the above-described group (I), alkyl group, hydroxyalkyl group and the like.
When the cyclic amine has a substituent, the substituent is preferably bonded to a carbon atom.
Among the cyclic amines, C═N—C, —NH—C (R ²⁰ ) ═N— [R ²⁰ is a hydrogen atom or a substituent in the ring skeleton among the above. ] Or> N—C (R ²⁰ ′) ═N— [R ²⁰ ′ is a hydrogen atom or a substituent. ], Especially imidazole, benzimidazole or 1,5-diazabicyclo [4.3.0] -5-nonene is preferred.
Moreover, the pyridine which may have a substituent is also preferable and the pyridine which has a substituent is more preferable. Examples of the substituent include the same substituents as those which may be included in the nitrogen-containing heterocyclic compound in the description of the “nitrogen-containing heterocyclic group” of the component (D1). .
As the pyridine which may have a substituent, pyridine having at least one alkyl group as a substituent is preferable, and 2,6-dialkylpyridine is more preferable. The alkyl group is preferably a branched alkyl group, and most preferably an iso-propyl group or a tert-butyl group.
Preferable examples of the cyclic amine include those represented by the following general formulas (d1-2-1) to (d1-2-4).

［式中、Ｒ^２０は水素原子または有機基を示す。Ｒ^６ａ〜Ｒ^６ｅはそれぞれ独立に水素原子または有機基を示す。］

[Wherein R ²⁰ represents a hydrogen atom or an organic group. R ^{6a to} R ^6e each independently represent a hydrogen atom or an organic group. ]

In formulas (d1-2-1) to (d1-2-2), examples of the organic group for R ²⁰ include the group (I) and the group (II).
R ²⁰ in the formula (d1-2-1) is preferably a group (I), more preferably a group represented by the formula (I-1), and in particular, — (R ⁶¹ O) n ₁ -R ^62. (Wherein R ⁶¹ , n ₁ and R ⁶² are the same as defined above), respectively.
In formula (d1-2-2), the plurality of R ²⁰ may be the same or different.
R ²⁰ in formula (d1-2-2) is preferably group (I), more preferably a group represented by formula (I-4), and particularly preferably a phenyl group.
In formula (d1-2-4), examples of the organic group for R ^{6a to} R ^6e include the group (I) and the group (II). Of these, the group (I) is preferably a group represented by the formula (I-5), particularly preferably R ⁶⁶ is a single bond. As the group (II), an alkyl group is preferable, and a branched or cyclic alkyl group is more preferable.
In formula (d1-2-4), R ^{6a to} R ^6e may be the same or different.
As the cyclic amine represented by the formula (d1-2-4), in particular, among R ^{6a to} R ^6e , R ^6c is a group represented by the formula (I-4), and the remainder is a hydrogen atom. Some are preferred, or those in which R ^6a and R ^6e are alkyl groups and the rest are hydrogen atoms.

As the component (D1), any one type may be used alone, or two or more types may be used in combination.
In the present invention, as the component (D1), a bulky structure is preferable because the effect of the present invention is excellent. Examples of the bulky structure include those having a branched structure or a ring structure. Specifically, (1) the primary amine or the secondary amine may have a substituent. Examples thereof include those having a good phenyl group or nitrogen-containing heterocyclic group, (2) tertiary amine, (3) cyclic amine, and the like.
The component (D1) is preferably at least one selected from the group consisting of a tertiary amine represented by the general formula (d1-1) and a cyclic amine, and in particular, the general formula (d1-1). -1) to (d1-1-6) and (d1-2-1) to (d1-2-3) are preferably at least one selected from the group consisting of. Particularly preferred are those having an optionally substituted phenyl group or nitrogen-containing heterocyclic group.
In the component (D), the proportion of the component (D1) is preferably 50% by mass or more, more preferably 75% by mass, and 100% by mass with respect to the total mass of the component (D) in consideration of the effects of the present invention. There may be.

The positive resist composition of the present invention may contain, as component (D), a nitrogen-containing organic compound (hereinafter referred to as component (D2)) that does not correspond to component (D1).
As the component (D2), a wide variety of acid diffusion control agents for resist compositions, that is, quenchers that trap the acid generated from the component (B) upon exposure have already been proposed. Any of these may be selected and used.
Examples of the component (D2) include amines (alkylamines or alkyl alcohol amines) in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group having 1 to 20 carbon atoms or a hydroxyalkyl group.
Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di- -Dialkylamines such as n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine , Tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine, and the like; diethanolamine, triethanolamine, diisopropanolamine Triisopropanolamine, di -n- octanol amine, tri -n- octanol amine, stearyl diethanolamine, alkyl alcohol amines such as lauryl diethanolamine. Among these, trialkylamine and / or alkyl alcohol amine are preferable.
These may be used alone or in combination of two or more.

  The content of the component (D) in the positive resist composition of the present invention is preferably 0.01 to 5.0 parts by mass, and 0.10 to 3.5 parts by mass with respect to 100 parts by mass of the component (A). More preferred. By setting it to be equal to or higher than the lower limit of the above range, the effect of the present invention can be sufficiently obtained. In addition, when the content is within the above range, the resist pattern shape, the stability over time, and the like are also improved.

<Optional component>
The positive resist composition of the present invention includes, as optional components, organic carboxylic acids, phosphorus oxoacids and derivatives thereof for the purpose of preventing sensitivity deterioration, improving the resist pattern shape, retention stability over time, etc. At least one compound (E) selected from the group consisting of (hereinafter referred to as component (E)) can be contained.
As the organic carboxylic acid, for example, acetic acid, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid and the like are suitable.
Examples of phosphorus oxo acids and derivatives thereof include phosphoric acid, phosphonic acid, phosphinic acid and the like, and among these, phosphonic acid is particularly preferable.
Examples of the oxo acid derivative of phosphorus include esters in which the hydrogen atom of the oxo acid is substituted with a hydrocarbon group, and the hydrocarbon group includes an alkyl group having 1 to 5 carbon atoms and 6 to 6 carbon atoms. 15 aryl groups and the like.
Examples of phosphoric acid derivatives include phosphoric acid esters such as di-n-butyl phosphate and diphenyl phosphate.
Examples of phosphonic acid derivatives include phosphonic acid esters such as phosphonic acid dimethyl ester, phosphonic acid-di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, and phosphonic acid dibenzyl ester.
Examples of the phosphinic acid derivatives include phosphinic acid esters such as phenylphosphinic acid.
(E) A component may be used individually by 1 type and may use 2 or more types together.
(E) A component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component.

  The positive resist composition of the present invention further contains miscible additives as desired, for example, additional resins for improving the performance of the resist film, surfactants for improving coating properties, dissolution inhibitors, Plasticizers, stabilizers, colorants, antihalation agents, dyes, and the like can be added and contained as appropriate. In addition, when the resist pattern is formed by immersion exposure, for example, a fluorine-based additive as described in JP-A-2008-134607 can be contained.

The positive resist composition of the present invention can be produced by dissolving the material in an organic solvent (hereinafter sometimes referred to as (S) component).
As the component (S), any component can be used as long as it can dissolve each component to be used to form a uniform solution. Conventionally, any one of known solvents for chemically amplified resists can be used. Two or more types can be appropriately selected and used.
For example, lactones such as γ-butyrolactone;
Ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, 2-heptanone;
Polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol;
Compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, monomethyl ether, monoethyl ether, monopropyl of the polyhydric alcohols or the compound having an ester bond Derivatives of polyhydric alcohols such as ethers, monoalkyl ethers such as monobutyl ether or compounds having an ether bond such as monophenyl ether [in these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME) Is preferred];
Cyclic ethers such as dioxane and esters such as methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate;
Aromatic organic solvents such as anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether, dibenzyl ether, phenetol, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc. be able to.
These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Among these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and EL are preferable.
Moreover, the mixed solvent which mixed PGMEA and the polar solvent is also preferable. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to be within the range.
More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Moreover, when mix | blending PGME as a polar solvent, the mass ratio of PGMEA: PGME becomes like this. Preferably it is 1: 9-9: 1, More preferably, it is 2: 8-8: 2, More preferably, it is 3: 7-7: 3.
In addition, as the component (S), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70:30 to 95: 5.
The amount of component (S) used is not particularly limited, but is a concentration that can be applied to a substrate or the like, and is appropriately set according to the coating film thickness. In general, the solid content concentration of the resist composition is 1 -20% by mass, preferably 2-15% by mass.

≪Resist pattern formation method≫
The resist pattern forming method of the present invention comprises a step of forming a resist film on a support using the positive resist composition of the present invention, a step of exposing the resist film, and developing the resist film to form a resist. Forming a pattern.
The resist pattern forming method of the present invention can be performed, for example, as follows.
That is, first, the positive resist composition of the present invention is applied onto a support with a spinner or the like, and pre-baked (post-apply bake (PAB)) for 40 to 120 seconds, preferably at a temperature of 80 to 150 ° C., preferably For 60 to 90 seconds, using an exposure apparatus such as an ArF exposure apparatus, an electron beam drawing apparatus, or an EUV exposure apparatus, exposure through a mask pattern, or drawing by direct irradiation of an electron beam without using a mask pattern, etc. Then, PEB (post-exposure heating) is applied for 40 to 120 seconds, preferably 60 to 90 seconds, at a temperature of 80 to 150 ° C. Subsequently, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide (TMAH), preferably rinsed with pure water and dried. In some cases, a baking process (post-bake) may be performed after the development process.
In this way, a resist pattern faithful to the mask pattern can be obtained.

The support is not particularly limited, and a conventionally known one can be used, and examples thereof include a substrate for electronic components and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.
Further, the support may be a substrate in which an inorganic and / or organic film is provided on the above-described substrate. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include an organic antireflection film (organic BARC).
The wavelength used for the exposure is not particularly limited, and ArF excimer laser, KrF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. Can be done using radiation. The resist composition is effective for KrF excimer laser, ArF excimer laser, EB or EUV, particularly ArF excimer laser.

The exposure method of the resist film may be normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or may be immersion exposure (Liquid Immersion Lithography).
In immersion exposure, the space between the resist film and the lens at the lowest position of the exposure apparatus is previously filled with a solvent (immersion medium) having a refractive index larger than that of air, and exposure (immersion exposure) is performed in that state. It is an exposure method.
As the immersion medium, a solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film to be exposed is preferable. The refractive index of such a solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent.
Specific examples of the fluorine-based inert liquid include a fluorine-based compound such as C ₃ HCl ₂ F ₅ , C ₄ F ₉ OCH ₃ , C ₄ F ₉ OC ₂ H ₅ , and C ₅ H ₃ F ₇ as a main component. Examples thereof include liquids, and those having a boiling point of 70 to 180 ° C are preferable, and those having a boiling point of 80 to 160 ° C are more preferable. It is preferable that the fluorine-based inert liquid has a boiling point in the above range since the medium used for immersion can be removed by a simple method after the exposure is completed.
As the fluorine-based inert liquid, a perfluoroalkyl compound in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms is particularly preferable. Specific examples of the perfluoroalkyl compound include a perfluoroalkyl ether compound and a perfluoroalkylamine compound.
More specifically, examples of the perfluoroalkyl ether compound include perfluoro (2-butyl-tetrahydrofuran) (boiling point: 102 ° C.). Examples of the perfluoroalkylamine compound include perfluorotributylamine ( Boiling point of 174 ° C.).
As the immersion medium, water is preferably used from the viewpoints of cost, safety, environmental problems, versatility, and the like.

According to the resist composition of the present invention, a high-resolution resist pattern can be formed, MEF when forming the resist pattern, in-plane uniformity (CDU) of the formed resist pattern dimension, resist to be formed The shape of the pattern (for example, the roundness of the hole when forming the hole pattern) is also good.
The reason why the above effect is obtained is not clear, but the following may be considered. That is, first, the component (A1) has a cyclic group containing —SO ₂ —, which is a polar group, at the end of a relatively long side chain, thereby forming a resist formed using the positive resist composition. It is considered that the improvement of the adhesion of the film to the support such as the substrate and the distribution of the component (B) in the resist film contribute to the improvement of the uniformity. In addition, the component (D1) has a specific functional group, thereby effectively capturing the acid generated from the component (B) and controlling its diffusion by controlling the base dissociation constant (pKb). Thus, it is presumed that the above effect is achieved. Furthermore, when the component (D1) has a benzene ring in its structure, it also has an effect of adjusting the transmittance of the resist film, which is considered to contribute to the above effect together with the control of the pKb. In addition, when the component (D1) has a bulky skeleton such as a phenyl group or a nitrogen-containing heterocyclic group, the distribution in the resist film of the component (D1) is considered to be more uniform, and it is estimated that it contributes to CDU improvement. .

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.
In this example, the unit represented by the chemical formula (1) is referred to as “compound (1)”, and the same applies to compounds represented by other formulas.
In the analysis by NMR, the internal standard of ¹ H-NMR is tetramethylsilane, and the internal standard of ¹⁹ F-NMR is hexafluorobenzene (however, the peak of hexafluorobenzene is -160 ppm).

[Monomer Synthesis Example 1 (Synthesis of Compound (1))]
Compound (1) used in the polymer synthesis example described later was synthesized by the following procedure.
In a 500 ml three-necked flask, under a nitrogen atmosphere, 20 g (105.14 mmol) of alcohol (1), 30.23 g (157.71 mmol) of ethyldiisopropylaminocarbodiimide (EDCI) hydrochloride and 0.6 g of dimethylaminopyridine (DMAP) After adding 300 ml of a THF solution of (5 mmol), 16.67 g (115.66 mmol) of the precursor (1) was added under ice cooling (0 ° C.), and the mixture was stirred at room temperature for 12 hours.
After confirming disappearance of the raw material by thin layer chromatography (TLC), 50 ml of water was added to stop the reaction. The reaction solvent was concentrated under reduced pressure, and the organic layer obtained by extraction three times with ethyl acetate was washed with water, saturated sodium bicarbonate and 1N-HClaq in this order. The product obtained by distilling off the solvent under reduced pressure was dried to obtain compound (1).

The instrumental analysis results of the obtained compound (1) are as follows. From this result, it was confirmed that the compound (1) had the structure shown below.
¹ H-NMR (CDCl ₃ , 400 MHz): δ (ppm) = 6.22 (s, 1H, H ^a ), 5.70 (s, 1H, H ^b ), 4.71-4.85 (m, 2H, H ^{c, d} ), 4.67 (s, 2H, H ^k ), 3.40-3.60 (m, 2H, H ^{e, f} ), 2.58-2.70 (m, 1H, ^{H g), 2.11-2.21 (m,} 2H, H h), 2.00 (s, 3H, H i), 1.76-2.09 (m, 2H, H j).

[Polymer Synthesis Example 1 (Synthesis of Polymer Compound 1)]
In a three-necked flask connected with a thermometer and a reflux tube, 11.77 g (69.23 mmol) of compound (2), 15.00 g (47.47 mmol) of compound (1), 16.58 g (63.29 mmol) Compound (3), 4.65 g (27.69 mmol) of Compound (4), 3.27 g (13.85 mmol) of Compound (5) were dissolved in 76.91 g of methyl ethyl ketone (MEK). To this solution, 22.1 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved. The resultant was dropwise added to 42.72 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature. The obtained reaction polymerization solution was dropped into a large amount of normal (n-) heptane, and the polymer was precipitated. The precipitated white powder was filtered, washed with n-heptane / isopropyl alcohol mixed solvent, and dried. As a result, 41 g of the target polymer compound 1 was obtained.
For this polymer compound 1, the standard polystyrene equivalent weight average molecular weight (Mw) determined by GPC measurement was 7,900, and the molecular weight dispersity (Mw / Mn) was 1.78. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o / p = It was 35/25/20/15/5.

[Polymer Synthesis Example 2 (Synthesis of Polymer Compound 2)]
Except that the type and molar ratio of the monomer used were changed, the polymer compound 2 as the target product was obtained in the same manner as in Polymer Synthesis Example 1. Compound (6) was synthesized in the same manner as Synthesis Examples 1 and 2 described in JP2009-223300A.
For this polymer compound 2, the standard polystyrene equivalent weight average molecular weight (Mw) determined by GPC measurement was 8,500, and the molecular weight dispersity (Mw / Mn) was 1.6. The copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 30 / It was 10/50/10.

[Polymer Synthesis Example 3 (Synthesis of Polymer Compound 3)]
Except that the molar ratio of the monomers to be used was changed, the polymer compound 3 as the target product was obtained in the same manner as in Polymer Synthesis Example 1.
With respect to this polymer compound 3, the standard polystyrene equivalent weight average molecular weight (Mw) determined by GPC measurement was 7,500, and the molecular weight dispersity (Mw / Mn) was 1.6. Further, the copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula [the structural formula is the same as that of the polymer compound 1]) obtained by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is L / m / n / o / p = 35/21/24/13/7.

[Acid Generator Synthesis Example 1 (Synthesis of (B) -1)]
35.6 g of compound (VII) was dissolved in 360 g of pure water, 360 g of dichloromethane and 38.0 g of compound (VIII) were added thereto, and the mixture was stirred at room temperature for 14 hours. Thereafter, the dichloromethane layer was separated, then washed with dilute hydrochloric acid and water, and the dichloromethane layer was concentrated and dried to obtain the target compound ((B) -1) (58 g) as a white solid.
This compound was analyzed by NMR.
¹ H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 1.64 (m, 6H, Ad), 1.82 (m, 6H, Ad), 1.94 (m, 3H, Ad), 3.35 (s, 3H, CH3), 4.55 (t, 2H, CF2CH2), 7.56 (d, 2H, Ar), 7.72-7.84 (m, 12H, Ar).
¹⁹ F-NMR (DMSO-d6, 376 MHz): δ (ppm) = − 111.2.
From the results of the above analysis, it was confirmed that the obtained compound had a structure represented by the following chemical formula (B) -1.

[Acid Generator Synthesis Example 2 (Synthesis of (B) -2)]
Compound (IX) (16.0 g) and pure water (131.7 g) were added to a three-necked flask, and hydrochloric acid (5.20 g) was added dropwise thereto. Heating under reflux was performed for 12 hours. The aqueous layer was washed with t-butyl methyl ether (TBME) (131.7 g) to obtain Compound (X) (10.0 g).
Next, compound (X) (10 g) and dichloromethane (100 g) were added to a three-necked flask in a nitrogen atmosphere, and the mixture was cooled to 5 ° C. or lower. N, N-dimethylaminopyridine (DMAP) (0.56 g) was added thereto and stirred at 5 ° C. or lower for 5 minutes. Thereafter, ethyl-N, N-dimethylaminopropylcarbodiimide (4.8 g) was added. Then, after stirring for 10 minutes, compound (XI) (3.5 g) was added. After completion of addition, the mixture was warmed to room temperature, stirred at room temperature for 15 hours, then washed with diluted hydrochloric acid and washed with pure water repeatedly. It was. The organic phase was added dropwise to n-hexane (1100 g) and reprecipitated to obtain Compound (XII) (10.9 g).

Next, compound (XII) (2.2 g), dichloromethane (13.8 g) and pure water (5.2 g) were mixed, and compound (XIII) (1.68 g) was added thereto, and the mixture was mixed at room temperature. Stir overnight. Thereafter, the organic phase was separated, and the organic phase was further washed four times with pure water (5.2 g). Then, dichloromethane was distilled off under reduced pressure, and the target compound ((B) -2) (2.4 g) was obtained by drying under reduced pressure.
This compound was analyzed by NMR.
¹ H-NMR (DMSO-d6, 400 MHz): δ (ppm) = 7.72-7.83 (m, 10H, ArH), 7.59 (s, 2H, ArH), 4.90 (m, 1H) _{, sultone), 4.78 (m,} 1H, anion sultone), 4.62-4.68 (m, 4H, CH 2 + sultone + anion sultone), 3.83-3.89 (m, 2H, sultone + anion sultone), 3.43 (m, 1H, sultone), 3.34 (m, 1H, anion sultone), 1.73-2.49 (m, 16H, CH ₃ + sultone + anion sultone).
¹⁹ F-NMR (DMSO-d6, 376 MHz): δ (ppm) = − 107.7.
From the results described above, it was confirmed that the obtained compound had a structure represented by the following chemical formula (B) -2.

<Comparative example 1, Examples 1-11>
Each component shown in Table 1 was mixed and dissolved to prepare a positive resist composition.
In addition, all the compounding quantities of (D) component in the comparative example 1 and Examples 1-11 are equimolar amounts.

In Table 1, each abbreviation indicates the following, and the numerical value in [] is the blending amount (part by mass).
(A) -1: The polymer compound 1.
(B) -1: Compound (B) -1.
(D) -1 to (D) -12: Compounds represented by the following chemical formulas (D) -1 to (D) -12, respectively.
(S) -1: γ-butyrolactone.
(S) -2: Mixed solvent of PGMEA / PGME = 6/4 (mass ratio).

The following evaluation was performed using the obtained resist composition.
[Formation of resist pattern and evaluation of shape]
An organic antireflection film composition “ARC29” (trade name, manufactured by Brewer Science) is applied onto an 8-inch silicon wafer with a coating apparatus ACT8 (product name, manufactured by Tokyo Electron), and 205 ° C. on a hot plate. By baking for 60 seconds and drying, an organic antireflection film having a film thickness of 82 nm was formed. Each of the positive resist compositions is applied onto the antireflection film by the coating apparatus, prebaked (PAB) at 100 ° C. for 60 seconds on a hot plate, and dried to obtain a film thickness of 120 nm. The resist film was formed.
Next, a mask (6% halftone) (contact hole pattern) is applied to the resist film with an ArF exposure apparatus NSR-S302A (Nikon Corporation; NA (numerical aperture) = 0.60, 2/3 annular illumination). ), The resist film was selectively irradiated with an ArF excimer laser (193 nm).
Subsequently, a post-exposure heating (PEB) treatment was performed at 100 ° C. for 60 seconds, and a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution “NMD-3” (trade name, Tokyo Ohka Kogyo Co., Ltd.) at 23 ° C. Manufactured for 30 seconds, followed by water rinsing with pure water for 30 seconds and post-baking at 100 ° C. for 60 seconds.
As a result, in any of the examples, a resist pattern (hereinafter referred to as a CH pattern) in which hole patterns with a hole diameter of 130 nm are arranged at equal intervals (pitch 260 nm) was formed on the resist film.

[Resolution evaluation]
In the above resist pattern formation, the optimum exposure dose EOP (mJ / cm ² ) at which the CH pattern is formed is obtained, and the limit resolution (nm) in the EOP is determined by a scanning electron microscope S-9220 (manufactured by Hitachi). Obtained using. The results are shown in Table 2 as “Resolution (nm)”.

[Mask error factor (MEF) evaluation]
In the EOP, the pitch was fixed at 260 nm, CH patterns with a diameter of 130 nm and a diameter of 150 nm were formed, and the MEF value was determined from the following equation.
MEF = | CD150-CD130 | / | MD150-MD130 |
In the above formula, CD150 and CD130 are the actual diameters (nm) of the CH patterns formed using the mask pattern targeting 150 nm in diameter and 130 nm in diameter, respectively. MD150 and MD130 are diameters (nm) targeted by the mask pattern, respectively, and MD150 = 150 and MD130 = 130.
The obtained results are shown in Table 2. Note that MEF is a parameter that indicates how faithfully mask patterns with different line widths and apertures can be reproduced with the same exposure when the pitch is fixed (mask reproducibility). MEF is the value. The closer to 1, the better the mask reproducibility.

[Shape evaluation]
Each CH pattern formed in the above [Formation of resist pattern] was observed from above using a scanning electron microscope S-9220 (manufactured by Hitachi), and the shape of each hole pattern was evaluated according to the following criteria. The results are shown in Table 2.
(Criteria)
○: There are few irregularities on the circumference of the hole pattern, and the roundness is high.
X: There are many unevenness | corrugations of the circumference part of a hole pattern, and roundness is low.

  As shown in Table 2, the resist compositions of Examples 1 to 11 were superior in both resolution and MEF as compared to Comparative Example 1, and the pattern shape was also good.

<Comparative example 2, Examples 12-17>
Each component shown in Table 3 was mixed and dissolved to prepare a positive resist composition.
In addition, all the compounding quantities of (D) component in the comparative example 2 and Examples 12-17 are equimolar amounts.

In Table 3, (B) -1, (D) -10, and (S) -2 are the same as those shown in Table 1, and the other abbreviations are as follows. Is a blending amount (part by mass).
(A) -2: The polymer compound 2.
(D) -13 to (D) -18: Compounds represented by the following chemical formulas (D) -13 to (D) -18, respectively.
(E) -1: salicylic acid.

The following evaluation was performed using the obtained resist composition.
[Resist Pattern Formation and Shape Evaluation-2]
An organic antireflection film composition “ARC29A” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto a 12-inch silicon wafer using a spinner and baked on a hot plate at 205 ° C. for 60 seconds to be dried. Thereby, an organic antireflection film having a film thickness of 89 nm was formed. Then, each of the resist compositions shown in Table 3 is applied onto the antireflection film using a spinner, prebaked (PAB) at 90 ° C. for 60 seconds on a hot plate, and dried. Thus, a resist film having a thickness of 100 nm was formed.
Next, a protective film-forming coating solution “TILC-057” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied onto the resist film using a spinner and heated at 90 ° C. for 60 seconds. A top coat having a thickness of 35 nm was formed.
Next, an ArF immersion exposure apparatus NSR-S609B (manufactured by Nikon Corporation; NA (numerical aperture) = 1.07, σ0.97) is applied to the resist film on which the top coat has been formed through a hole pattern mask. On the other hand, ArF excimer laser (193 nm) was selectively irradiated.
Then, a post-exposure heating (PEB) treatment was performed at 85 ° C. for 60 seconds, and further a condition of 30 seconds with a 2.38 mass% TMAH aqueous solution NMD-3 (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 23 ° C. Then, the substrate was alkali-developed, rinsed with pure water for 25 seconds, and then shaken and dried.
As a result, in each example, a contact hole pattern (hereinafter referred to as “CH pattern”) in which holes having a hole diameter of 85 nm are arranged at equal intervals (pitch 140 nm) was formed in the resist film.

[sensitivity]
The optimum exposure dose EOP (mJ / cm ² ; sensitivity) when the above pattern was formed was determined. The results are shown in Table 3.

[CDU (Hole Diameter Uniformity) Evaluation-2]
About the obtained CH pattern, the diameter of each hole was measured with a length measurement SEM (scanning electron microscope “S-9380” manufactured by Hitachi, Ltd.), and the standard deviation (σ) calculated from the result was 3 times (3σ ) 3σ obtained in this way means that the smaller the value, the higher the CDU of each hole formed in the resist film, that is, the smaller the variation in the diameter of the holes existing within a certain range. The results are shown in Table 3.

[MEF evaluation-2]
In the EOP, CH patterns having the same pitch (140 nm) were formed by changing the target size of the hole diameter in the range of 81 to 87 nm in 1 nm increments. At this time, the slope of the straight line when the target size (nm) was plotted on the horizontal axis and the aperture (nm) of the hole pattern formed in the resist film using each mask pattern was plotted on the vertical axis was calculated as MEF. MEF (straight line) means that the closer the value is to 1, the better the mask reproducibility. The results are shown in Table 3.

From the results shown in Table 3, it was confirmed that the resist compositions of Examples 12 to 17 were superior in CDU to the resist composition of Comparative Example 2, respectively. In particular, the component (D) has an aromatic ring such as a benzene ring or a pyridine ring, or has a bulky structure including a plurality of rings ((D) -14, (D) -10, (D)- 15, CDD of Examples 12-16 using (D) -16, (D) -17) were good.
In addition, the resist compositions of Examples 12 to 17 had an MEF value equal to or less than that and good mask reproducibility.

<Comparative Example 3, Example 18>
Each component shown in Table 4 was mixed and dissolved to prepare a positive resist composition.
In addition, all the compounding quantities of (D) component in the comparative example 3 and Example 118 are equimolar amounts.

In Table 4, (D) -13, (D) -10, and (S) -2 are the same as those shown in Table 3, and the other abbreviations are as follows. Numerical values in [] Is a blending amount (parts by mass).
(A) -3: The polymer compound 3.
(B) -2: Compound (B) -2.
(B) -3: Triphenylsulfonium d-camphor-10-sulfonate.
(E) -1: salicylic acid.

The following evaluation was performed using the obtained resist composition.
[Resist Pattern Formation and Shape Evaluation-3]
The resist composition described in Table 4 was used in the same manner as in [Resist pattern formation and shape evaluation-2], except that the mask pattern was changed to one that targets the following CH pattern or LS pattern. A pattern was formed.
CH pattern: a resist pattern in which holes with a hole diameter of 90 nm are arranged at equal intervals (pitch 225 nm).
LS pattern: A 1: 1 line-and-space resist pattern in which lines with a line width of 80 nm are arranged at equal intervals (pitch 160 nm).

[sensitivity]
The optimum exposure dose EOP (mJ / cm ² ; sensitivity) when the CH pattern and LS pattern were formed was determined. The results are shown in Table 5.

[CDU Evaluation-3]
For the CH pattern, as in [CDU (Hole Diameter Uniformity) Evaluation-2], the diameter of each hole was measured, and the standard deviation (σ) calculated from the result was obtained (3σ). For the LS pattern, the line width was measured in the longitudinal direction of the line, and the triple value (3 s) of the standard deviation (s) was obtained from the result, and the value averaged over 5 s was taken as LWR. The results are shown in Table 5.

[MEF evaluation-3]
As for the CH pattern, as in [MEF evaluation-2] above, a CH pattern having the same pitch (225 nm) in which the target size of the hole diameter was changed in 1 nm increments in the range of 87 to 92 nm was obtained to obtain the MEF. . With respect to the LS pattern, an LS pattern having the same pitch (160 nm) was formed by changing the target size of the line width in the range of 76 to 84 nm in 1 nm increments, and the MEF was obtained. The results are shown in Table 5.

  From the results shown in Table 5, it was confirmed that the resist composition of Example 18 had better CDU and MEF than the resist composition of Comparative Example 3 in any resist pattern.

Claims (8)

A positive resist composition containing a base component (A) whose solubility in an alkaline developer is increased by the action of an acid, an acid generator component (B) that generates an acid upon exposure, and a nitrogen-containing organic compound (D) Because
The base material component (A) has a structural unit (a0) represented by the following general formula (a0-1) and contains an acid dissociable, dissolution inhibiting group in its structure (A1) Containing
The nitrogen-containing organic compound (D) is selected from the group consisting of an etheric oxygen atom, an ester group, a carbonyl group, a cyano group, an optionally substituted phenyl group, and a nitrogen-containing heterocyclic group. A positive resist composition comprising an amine (D1) containing at least one kind.

[In the formula (a0-1), R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ² is a divalent linking group, and R ³ is It is a cyclic group containing —SO ₂ — in the ring skeleton. ] The positive resist composition according to claim 1, wherein the amine (D1) is selected from the group consisting of a tertiary amine represented by the following general formula (d1-1) and a cyclic amine.

[Wherein, R ^{7 to} R ⁹ are each independently a hydrocarbon group which may have a substituent, and at least one of R ^{7 to} R ⁹ is an ether in its structure. An oxygen atom, an ester group, a carbonyl group, a cyano group, a phenyl group which may have a substituent, and at least one selected from the group consisting of a nitrogen-containing heterocyclic group, and R ^{7 to} R ⁹ Any two of them may be bonded to each other to form a ring together with the nitrogen atom in the formula. ] The positive resist composition according to claim 1, wherein R ³ is a cyclic group containing —O—SO ₂ — in the ring skeleton. The positive resist composition according to claim 3, wherein R ³ is a cyclic group represented by the following general formula (3-1).

Wherein A ′ is an alkylene group having 1 to 5 carbon atoms, oxygen atom or sulfur atom which may contain an oxygen atom or a sulfur atom; a is an integer of 0 to 2; R ⁶ is an alkyl group An alkoxy group, a halogenated alkyl group, a hydroxyl group, —COOR ″, —OC (═O) R ″, a hydroxyalkyl group or a cyano group, and R ″ is a hydrogen atom or an alkyl group.]   The positive resist composition according to claim 1, wherein the polymer compound (A1) further has a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group. object.   The positive resist composition according to claim 1, wherein the polymer compound (A1) further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group. .   The positive type according to any one of claims 1 to 6, wherein the polymer compound (A1) further has a structural unit (a3) derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group. Resist composition.   A step of forming a resist film on the support using the positive resist composition according to any one of claims 1 to 7, a step of exposing the resist film, and an alkali development of the resist film A resist pattern forming method including a step of forming a resist pattern.