KR102765319B1 - Resist composition and method of forming resist pattern - Google Patents

Abstract

The present invention relates to a resist composition containing a resin component (A) whose solubility in a developer changes by the action of an acid, an acid generator component (B) which generates acid by exposure, and a compound (C) having a radiation absorption ability represented by the following formula (1).
Equation (1)
[During the meal,
R ₁ and R ₂ are each independently a hydrocarbon group having 1 to 10 carbon atoms which can be substituted with a hydroxyl group, and among the hydrocarbon groups, one -CH ₂ - or two or more -CH ₂ - which are not adjacent can be replaced by -O-, -S-, -NH-, -NR ₃ -, -C(O)-, -OC(O)-, -OC(O)O-, -SO-, -SO ₂ -, -CONH-, -CONR ₃ -, -OC(O)NH- or -OC(O)NR ₃ -, wherein R ₃ is a hydrocarbon group having 1 to 10 carbon atoms.
n1, n2, m1, and m2 are each independently integers from 0 to 5, and n1 + m1 and n2 + m2 do not both exceed 5.]

Description

{RESIST COMPOSITION AND METHOD OF FORMING RESIST PATTERN}

The present invention relates to a resist composition and a method for forming a resist pattern.

In photolithography technology, for example, a process is carried out in which a resist film made of a resist composition is formed on a substrate, the resist film is selectively exposed to radiation such as light or electron beams through a photomask having a predetermined pattern formed thereon, and a development process is performed to form a resist pattern of a predetermined shape on the resist film. A resist composition in which an exposed portion changes to have the characteristic of being soluble in a developer is called a positive type, and a resist composition in which an exposed portion changes to have the characteristic of being insoluble in a developer is called a negative type.

Recently, in the manufacturing of semiconductor devices and liquid crystal display devices, rapid miniaturization is progressing due to the advancement of lithography technology. As a means of miniaturization, shortening the wavelength of exposure light is generally implemented, and specifically, in the past, ultraviolet rays represented by g-line and i-line were used, but currently, KrF excimer lasers (248 nm) have been introduced, and ArF excimer lasers (193 nm) are also beginning to be introduced. In addition, studies are being conducted on shorter wavelength F ₂ excimer lasers (157 nm), EUV (extreme ultraviolet), electron beams, X-rays, etc.

Meanwhile, in the manufacture of semiconductor devices or liquid crystal display devices, an impurity diffusion layer is formed on the surface of the substrate. The formation of the impurity diffusion layer is usually carried out in two stages: introduction and diffusion of impurities. One of the introduction methods is ion implantation (hereinafter referred to as implantation), which ionizes impurities such as phosphorus or boron in a vacuum, accelerates them in a high electric field, and implants them on the surface of the substrate.

However, in the inclined implantation process (hereinafter referred to as the thin film implantation process) using such a thin film resist pattern, it is generally performed without using an antireflection film (BARC) in consideration of the influence on the subsequent ion implantation. In this case, especially when a resin with high transparency to exposure light is used, the shape defect of the resist pattern is easily caused by the influence of incident light or reflected light from the substrate during exposure. In particular, when manufacturing semiconductor elements and liquid crystal display elements, since the thin film implantation process is performed on a substrate on which electrodes, etc. are formed, it is difficult to form a resist film with a uniform film thickness on the substrate. Therefore, for example, there is a problem of the so-called standing wave (hereinafter abbreviated as SW), a phenomenon in which the dimensions of the resist pattern increase or decrease depending on a change in the thickness of the resist film. The change in pattern dimensions due to SW tends to increase as the resist film becomes thinner and the transparency of the resist film increases, and is particularly noticeable in the case of films with a film thickness of 500 nm or less. In addition, the problem of dimensional change becomes a serious problem as the resist pattern becomes finer.

In addition, as semiconductor devices become three-dimensional, the structure of devices becomes more sophisticated and complex, and when manufacturing integrated circuit devices having a three-dimensional structure, there are cases where resist patterns are formed on step substrates. In such cases, shape defects (SW) of the resist pattern are likely to occur due to the influence of incident light during exposure or reflected light from the substrate.

To improve these problems, resist compositions have been used in which a compound containing an anthracene skeleton or a benzophenone skeleton, a so-called radiation-absorbing compound (dye), is mixed into the resist to absorb reflected light from the substrate, thereby suppressing pattern dimensional changes due to SW (see, for example, Patent Documents 1 and 2).

Patent Document 1: Japanese Patent Publication No. 2006-215163

Patent Document 2: Japanese Patent Publication No. 2011-113065

However, compounds containing an anthracene skeleton or benzophenone skeleton have the problem of toxicity (high risk to the human body), making it difficult to use them as dyes at present.

The present invention has been made in consideration of the above circumstances, and aims to provide a resist composition and a method for forming a resist pattern, which can effectively suppress pattern dimensional changes caused by SW while maintaining resolution and having a high absorption rate for exposure light with a small amount of additive, while taking into account the problem of toxicity.

The present inventors, as a result of careful examination, have found that the above problem can be solved by combining a resin component (A) whose solubility in a developer changes by the action of an acid, an acid generator component (B) which generates acid by exposure, and a compound (C) which has an absorption ability for a specific dye, i.e., exposure light (radiation), thereby completing the present invention.

That is, the first aspect of the present invention is,

[1] A resist composition containing a resin component (A) whose solubility in a developer changes by the action of an acid, an acid generator component (B) which generates acid by exposure, and a compound (C) having a radiation absorption ability represented by the following formula (1).

[Chemical Formula 1]

Equation (1)

[During the meal,

R ₁ and R ₂ are each independently a hydrocarbon group having 1 to 10 carbon atoms which can be substituted with a hydroxyl group, and among the hydrocarbon groups, one -CH ₂ - or two or more -CH ₂ - which are not adjacent can be replaced by -O-, -S-, -NH-, -NR ₃ -, -C(O)-, -OC(O)-, -OC(O)O-, -SO-, -SO ₂ -, -CONH-, -CONR ₃ -, -OC(O)NH- or -OC(O)NR ₃ -, wherein R ₃ is a hydrocarbon group having 1 to 10 carbon atoms.

n1, n2, m1, and m2 are each independently integers from 0 to 5, and n1 + m1 and n2 + m2 do not both exceed 5.]

[2] In a compound (C) having a radiation absorption capacity represented by the above formula (1), m1 = m2 = 1.

[3] In the compound (C) having radiation absorption ability represented by the above formula (1), R ₁ and R ₂ are each independently a hydrocarbon group having 1 to 5 carbon atoms substituted with a hydroxyl group, and among the hydrocarbon groups, one -CH ₂ - or two or more -CH ₂ - which are not adjacent can be replaced with -O-, -S- or -NH-.

[4] The above resin component (A) may contain a structural unit (a1) derived from hydroxystyrene represented by the following formula (a1-1):

[During the meal,

R is hydrogen, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms that can be substituted with a halogen atom.

^R6 is a hydrocarbon group having 1 to 10 carbon atoms.

p is an integer from 1 to 3.

q is an integer from 0 to 2.]

[5] The above resin component (A) may contain a polymer compound (A-2) having a structural unit (a4) derived from an acrylic acid ester represented by the following formula (a4-1) or (a4-2).

[During the meal,

R is hydrogen, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms that can be substituted with a halogen atom.

Va ¹ is a divalent hydrocarbon group having 1 to 30 carbon atoms that may have an ether bond, a urethane bond, or an amide bond.

n _a1 is an integer from 0 to 2.

Ra ¹ is a acid-soluble group.

n _a2 is an integer from 1 to 3.

Wa ¹ is a hydrocarbon group having 1 to 30 carbon atoms and valence n _a2 +1.]

[6] The above resin component (A) may be a resin whose alkaline solubility increases by the action of an acid.

[7] The above resin component (A) is an alkali-soluble resin and may additionally include a crosslinking agent component (D).

[8] The above resist composition may additionally contain a nitrogen-containing organic compound (E).

[9] The above resist composition can be used for a thin film implantation process.

[10] The above resist composition can be used to form a resist pattern on a step substrate.

The second aspect of the present invention is,

[11] A method for forming a resist pattern, characterized by forming a resist film on a substrate using the resist composition of the first aspect, performing a selective exposure process on the resist film, and then performing a development process to form a resist pattern.

According to the present invention, it is possible to provide a resist composition and a method for forming a resist pattern, which have a low toxicity problem, have a high absorption rate for exposure light with a small amount of additive, and can effectively suppress pattern dimensional changes caused by SW while maintaining resolution.

In this specification and the claims of this patent, "hydrocarbon group" means a monovalent residue derived from an organic compound composed of carbon and hydrogen or a derivative thereof. Examples of the hydrocarbon group include an alkyl group, an alkenyl group, an alkynyl group, an aryl group, and the like.

“Aliphatic” is a relative concept to aromatic, and is defined as a group, compound, etc. that does not have aromaticity.

“Aliphatic hydrocarbon group” means a hydrocarbon group that does not have aromaticity.

An “aromatic hydrocarbon group” is a hydrocarbon group that has aromaticity.

“Aliphatic cyclic group” means a monocyclic group or polycyclic group that does not have aromaticity.

“Alkyl group” is defined as a monovalent saturated hydrocarbon group that includes a straight-chain, branched-chain, or cyclic group.

“Alkylene group” is defined as a divalent saturated hydrocarbon group that includes a straight-chain, branched-chain, or cyclic group.

A “halogenated alkyl group” is a group in which some or all of the hydrogen atoms of the alkyl group are replaced with halogen atoms, and examples of the halogen atoms include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms.

“Component unit” refers to a monomer unit (monomer unit) that constitutes a high molecular weight compound (resin, polymer, copolymer).

“Exposure” is a concept that includes all exposure to radiation.

< Registry Composition>

The resist composition of the present invention (hereinafter, sometimes simply referred to as “resist composition”) is a resist composition containing a resin component (A) whose solubility in a developer changes by the action of an acid (hereinafter, referred to as component (A)), an acid generator component (B) that generates acid by exposure (hereinafter, referred to as component (B)), and a compound (C) having radiation absorption capability (hereinafter, referred to as component (C)).

When a resist film is formed using the resist composition of the present invention and selective exposure is performed on the resist film, acid is generated in the exposed portion and the solubility of component (A) in the developing solution changes due to the action of the acid, whereas in the unexposed portion, the solubility of component (A) in the developing solution does not change, so a difference in solubility in the developing solution occurs between the exposed portion and the unexposed portion. Therefore, when the resist film is developed, if the resist composition is positive, the exposed portion is dissolved and removed, forming a positive resist pattern, and if the resist composition is negative, the unexposed portion is dissolved and removed, forming a negative resist pattern.

The resist composition of the present invention may be a positive resist composition or a negative resist composition.

In addition, the resist composition of the present invention may be used for an alkaline developing process that uses an alkaline developer for the developing treatment at the time of forming a resist pattern, or may be used for a solvent developing process that uses a developer containing an organic solvent (organic developer) for the developing treatment.

The resist composition used to form a resist pattern has an acid-generating ability that generates an acid upon exposure, and the component (A) may be a "base component that generates an acid upon exposure and further changes its solubility in a developer solution by the action of the acid." In this case, the component (A) is preferably a polymer compound. As such a polymer compound, a resin having a structural unit that generates an acid upon exposure can be used. As the structural unit that generates an acid upon exposure, a known one can be used.

<(A) Component>

(A) There is no particular limitation on the component, as long as it is a resin component whose solubility in a developer changes due to the action of an acid, and it can be arbitrarily selected from among those currently used as alkali-soluble resin components.

(A) It is preferable that component (a1) contains a structural unit derived from hydroxystyrene, a structural unit (a2) formed by substituting a hydrogen atom of a hydroxyl group of the structural unit (a1) with an acid-labile group, and/or a structural unit (a3) derived from styrene (hereinafter, sometimes referred to as component (A-1)).

In addition, it is preferable that component (A) contains a structural unit (a4) containing an acid-decomposable group whose polarity increases by the action of an acid, a structural unit (a5) containing a -SO ₂ --containing cyclic group, a lactone-containing cyclic group, a carbonate-containing cyclic group or a heterocyclic group other than these, and/or a structural unit (a6) containing an aliphatic hydrocarbon group containing a polar group (hereinafter, sometimes referred to as component (A-2)).

The following is a detailed description of the components (A-1).

constituent unit (a1)

The constituent unit (a1) is a constituent unit derived from hydroxystyrene.

"Hydroxystyrene" is a concept that includes hydroxystyrene, and hydroxystyrene in which the hydrogen atom at the α-position is replaced by another substituent such as a halogen atom, an alkyl group, a halogenated alkyl group, and the like, and derivatives thereof. "Constituent unit derived from hydroxystyrene" means a constituent unit formed by the cleavage of the ethylenic double bond of hydroxystyrene. In addition, "the α-position of the constituent unit derived from hydroxystyrene (carbon atom at the α-position)" means, unless otherwise specified, a carbon atom to which a benzene ring is bonded.

As the constituent unit (a1), a constituent unit represented by the following formula (a1-1) can be exemplified.

[Chemical formula 2]

[During the meal,

R is a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms that can be substituted with a halogen atom.

^R6 is a hydrocarbon group having 1 to 10 carbon atoms.

p is an integer from 1 to 3.

q is an integer from 0 to 2.]

In formula (a1-1), R can be a hydrogen atom, an alkyl group, a halogen atom, or a halogenated alkyl group.

The alkyl group of R may be an alkyl group having 1 to 5 carbon atoms, and is preferably a linear or branched alkyl group, and examples thereof 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, and a neopentyl group. Industrially, a methyl group is preferable.

The halogen atom of R may include a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, among which a fluorine atom is preferred.

The halogenated alkyl group of R is one in which some or all of the hydrogen atoms of the above-described alkyl group having 1 to 5 carbon atoms are replaced with halogen atoms. At this time, the halogen atom may be a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, and among these, a fluorine atom is preferable. That is, it is preferable that the halogenated alkyl group is a fluorinated alkyl group.

The fluorinated alkyl group of R is preferably one in which all of the hydrogen atoms are fluorinated. As the fluorinated alkyl group, a linear or branched fluorinated alkyl group is preferable, and a trifluoromethyl group, a hexafluoroethyl group, a heptafluoropropyl group, a nonafluorobutyl group, etc. are more preferable, and a trifluoromethyl group (-CF ₃ ) is most preferable.

For R, a hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

In formula (a1-1), R ⁶ can be an alkyl group having 1 to 5 carbon atoms.

As the alkyl group of R ⁶ , the same alkyl group as that of R can be mentioned.

In formula (a1-1), q is preferably 0 or 1, and is particularly preferably 0 for industrial purposes. The substitution position of R ⁶ may be any of the o-position, m-position, and p-position when q is 1, and further, when q is 2, any combination of substitution positions may be used.

In formula (a1-1), p is preferably 1. The substitution position of the hydroxyl group may be any of the o-position, m-position, and p-position when p is 1, but the p-position is preferred because it is easily available and inexpensive. In addition, when p is 2 or 3, any combination of substitution positions may be used.

The composition unit (a1) can be used alone or in combination of two or more types.

(A-1) When the component contains the structural unit (a1), the proportion of the structural unit (a1) is preferably 50 to 95 mol%, more preferably 60 to 80 mol%, with respect to the total structural units constituting the component (A-1). Within that range, solubility in an appropriate developer is obtained, and the balance with other structural units is good.

constituent unit (a2)

The structural unit (a2) is a structural unit formed by replacing the hydrogen atom of the hydroxyl group of the structural unit (a1) with an acid-labile group.

As the above acid dissociation group, it is preferable to contain an acid dissociation group (II) represented by the following formula (II) as a main component.

[Chemical Formula 3]

[During the meal,

X and R ¹ are each independently a hydrocarbon group having 1 to 16 carbon atoms, or X and R ¹ are each independently an alkylene group having 1 to 16 carbon atoms, and the terminal of X and the terminal of R ¹ may be combined to form a ring.

R ² is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.]

Here, “contains as a main component” means that more than 50 mol% of the acid-dissociable groups contained in component (A-1) are acid-dissociable groups (II), preferably 70 mol% or more, more preferably 80 mol% or more, and most preferably 100 mol%.

In formula (II), X can be an aliphatic cyclic hydrocarbon group or an aromatic cyclic hydrocarbon group.

The aliphatic cyclic hydrocarbon group in X is a monovalent aliphatic group. The aliphatic cyclic hydrocarbon group can be appropriately selected and used from among those proposed, for example, in conventional KrF resists and ArF resists. Specific examples of the aliphatic cyclic hydrocarbon group in X include, for example, an aliphatic monocyclic group having 5 to 10 carbon atoms and an aliphatic polycyclic group having 7 to 16 carbon atoms. As the aliphatic monocyclic group having 5 to 10 carbon atoms, a group obtained by removing one hydrogen atom from a monocycloalkane can be exemplified, and specific examples thereof include a group obtained by removing one hydrogen atom from cyclopentane, cyclohexane, cyclooctane, and the like. As an aliphatic polycyclic group having 7 to 16 carbon atoms, examples thereof include groups in which one hydrogen atom has been removed from a bicycloalkane, a tricycloalkane, a tetracycloalkane, etc., and specifically, examples thereof include groups in which one hydrogen atom has been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Of these, an adamantyl group, a norbornyl group, and a tetracyclododecanyl group are industrially preferable, and an adamantyl group is particularly preferable.

As the aromatic cyclic hydrocarbon group of X, an aromatic polycyclic group having 10 to 16 carbon atoms can be exemplified. Specifically, groups obtained by removing one hydrogen atom from naphthalene, anthracene, phenanthrene, pyrene, etc. can be exemplified. Specifically, a 1-naphthyl group, a 2-naphthyl group, a 1-anthracenyl group, a 2-anthracenyl group, a 1-phenanthryl group, a 2-phenanthryl group, a 3-phenanthryl group, a 1-pyrenyl group, etc. can be exemplified, and a 2-naphthyl group is particularly preferable from an industrial perspective.

X can be a linear, branched, or cyclic hydrocarbon group.

As the linear hydrocarbon group, a linear alkyl group is preferable, and specific examples thereof 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 the like. The linear aliphatic hydrocarbon group preferably has 1 to 8 carbon atoms, and more preferably has 1 to 5 carbon atoms.

As the branched-chain aliphatic hydrocarbon group, a branched-chain alkyl group is preferable, and specific examples thereof include -CH(CH ₃ )CH ₃ , -C(CH ₃ ) ₂ CH ₃ , -CH(CH ₂ CH ₃ )CH ₃ ; alkylpropyl groups such as -CH(CH ₃ )CH ₂ CH ₃ , -CH ₂ CH(CH ₃ )CH ₃ ; alkylbutyl groups such as -CH(CH ₃ )CH ₂ CH ₂ CH ₃ , -CH ₂ CH(CH ₃ )CH ₂ CH ₃ . The branched-chain aliphatic hydrocarbon group preferably has 1 to 8 carbon atoms, and more preferably has 1 to 5 carbon atoms.

The above-mentioned cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group, but a monocyclic group is preferred. Examples of the monocyclic group include cyclopentyl and cyclohexyl, and examples of the polycyclic group include isobornyl, norbornyl, tricyclodecanyl, etc. The above-mentioned cyclic aliphatic hydrocarbon group preferably has 3 to 10 carbon atoms, and more preferably has 5 to 10 carbon atoms.

The aromatic hydrocarbon group of R ₁ and R ₂ is a concept including an aralkyl group and an alkylaryl group, and specifically, can include a phenyl group, a phenylethyl group, a phenylpropyl group, a benzyl group, a naphthalene group, etc.

As the hydrocarbon group of X, an alkyl group is preferable. As the alkyl group of X, the same as the alkyl group of R in the above formula (a1-1) can be mentioned, and at this time, the alkyl group is preferably a methyl group or an ethyl group, and an ethyl group is more preferable.

In formula (II), R ¹ can be an alkyl group having 1 to 5 carbon atoms.

As the alkyl group of R ¹ , the same alkyl group as the alkyl group of R in the above formula (a1-1) can be mentioned. Industrially, a methyl group or an ethyl group is preferable, and a methyl group is particularly preferable.

In formula (II), R ² can be a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

As the alkyl group of R ² , the same alkyl group as that of R ¹ can be mentioned. Industrially, it is preferable that R ² be a hydrogen atom.

In addition, in formula (II), X and R ¹ are each independently an alkylene group having 1 to 5 carbon atoms, and the terminal of X and the terminal of R ¹ may be bonded to form a ring. In this case, in formula (II), a cyclic group is formed by R ¹ , X , the oxygen atom to which X is bonded, and the carbon atom to which the oxygen atom and R ¹ are bonded. As the cyclic group, a 4 to 7-membered ring is preferable, and a 4 to 6-membered ring is more preferable. Specific examples of the cyclic group include a tetrahydropyranyl group, a tetrahydrofuranyl group, and the like.

As the acid-dissociable group (II), a group in which R ² is a hydrogen atom is particularly preferable because the effect of the present invention is excellent. As a specific example, for example, a group in which X is an alkyl group, that is, a 1-alkoxyalkyl group, may include a 1-methoxyethyl group, a 1-ethoxyethyl group, a 1-iso-propoxyethyl group, a 1-n-butoxyethyl group, a 1-tert-butoxyethyl group, a methoxymethyl group, an ethoxymethyl group, an iso-propoxymethyl group, an n-butoxymethyl group, a tert-butoxymethyl group, and the like, and among these, a 1-ethoxyethyl group is particularly preferable. Furthermore, as a group in which X is an aliphatic cyclic group, may include a 1-cyclohexyloxyethyl group, a 1-(2-adamantyl)oxymethyl group, a 1-(1-adamantyl)oxyethyl group represented by the following formula (II-a), and the like. In addition, examples of groups in which X is an aromatic cyclic hydrocarbon group include a 1-(2-naphthyl)oxyethyl group represented by the following formula (Ⅱ-b).

[Chemical Formula 4]

In the present invention, as an acid dissociable group, an acid dissociable group other than the acid dissociable group (II) represented by the above formula (II) may be present, as long as the effect of the present invention is not impaired.

Among these acid-dissociating groups, for example, resins for resist compositions for KrF excimer lasers, ArF excimer lasers, etc., can be appropriately selected and used from among those proposed.

As such acid-dissociable groups, at least one acid-dissociable group (II) selected from the group consisting of a chain-shaped tertiary alkoxycarbonyl group, a chain-shaped or cyclic tertiary alkyl group, and a chain-shaped tertiary alkoxycarbonylalkyl group can be exemplified. By including the acid-dissociable group (II), heat resistance is improved.

The number of carbon atoms in the chain-type tertiary alkoxycarbonyl group is preferably 4 to 10, more preferably 4 to 8. Specific examples of the chain-type tertiary alkoxycarbonyl group include a tert-butoxycarbonyl group, a tert-amyloxycarbonyl group, and the like.

The number of carbon atoms in the chain-shaped tertiary alkyl group is preferably 4 to 10, more preferably 4 to 8. More specifically, examples of the chain-shaped tertiary alkyl group include a tert-butyl group, a tert-amyl group, and the like.

A cyclic tertiary alkyl group is a monocyclic or polycyclic monovalent saturated hydrocarbon group containing a tertiary carbon atom on the ring. More specifically, examples of the cyclic tertiary alkyl group include a 1-methylcyclopentyl group, a 1-ethylcyclopentyl group, a 1-methylcyclohexyl group, a 1-ethylcyclohexyl group, a 2-methyl-2-adamantyl group, and a 2-ethyl-2-adamantyl group.

The number of carbon atoms in the chain-type tertiary alkoxycarbonyl alkyl group is preferably 4 to 10, more preferably 4 to 8. Specific examples of the chain-type tertiary alkoxycarbonyl alkyl group include a tert-butoxycarbonylmethyl group, a tert-amyloxycarbonylmethyl group, and the like.

As for the acid dissociation group (Ⅱ), in terms of resolution, a chain-shaped tertiary alkyl group is particularly preferable, and among them, a tert-butyl group is preferable.

The composition unit (a2) can be used alone or in combination of two or more types.

When the component (A-1) contains the structural unit (a2), the proportion of the structural unit (a2) is preferably 5 to 40 mol%, more preferably 10 to 35 mol%, with respect to the total structural units constituting (A-1). By making it equal to or greater than the lower limit, a pattern can be obtained when the resist composition is used, and by making it equal to or less than the upper limit, the balance with other structural units is good.

constituent unit (a3)

The constituent unit (a3) is a constituent unit derived from styrene.

Here, "styrene" is a concept including styrene, and styrene in which the hydrogen atom at the α-position is replaced by another substituent such as a halogen atom, an alkyl group, a halogenated alkyl group, and the like, and derivatives thereof (however, excluding hydroxystyrene). "Structure unit derived from styrene" means a structure unit formed by cleavage of the ethylenic double bond of styrene. Styrene may have the hydrogen atom of the phenyl group replaced by a substituent such as an alkyl group.

As a composition unit (a3), a composition unit represented by the following formula (a3-1) can be exemplified.

[Chemical Formula 5]

[During the meal,

R is a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms that can be substituted with a halogen atom.

R ⁷ is a hydrocarbon group having 1 to 10 carbon atoms.

r represents an integer from 0 to 3.]

In formula (a3-1), R and R ⁷ can be the same as R and R ⁶ in formula (a1-1).

In formula (a3-1), r is preferably 0 or 1, and is particularly preferably 0 for industrial purposes.

In formula (a3-1), the substitution position of R ⁷ can be any of the o-position, m-position, and p-position when r is 1 to 3, and any combination of substitution positions can be used when r is 2 or 3.

As for the composition unit (a3), one type may be used alone, or two or more types may be used in combination.

When the component (A-1) contains the structural unit (a3), the proportion of the structural unit (a3) is preferably 1 to 20 mol%, more preferably 5 to 10 mol%, with respect to the total structural units constituting the component (A-1). Within this range, the effect of having the structural unit (a3) is high, and the balance with other structural units is also good.

(A-1) The component may contain other structural units than the structural units (a1) to (a3) above, as long as the effects of the present invention are not impaired. These structural units are not particularly limited as long as they are other structural units not classified into the structural units (a1) to (a3) described above, and many of those known in the art as being used in resist resins for KrF excimer lasers, ArF excimer lasers, etc. can be used.

(A-1) As the component, a copolymer having the structural unit (a1), the structural unit (a2) and/or (a3), and optionally one or more other structural units may be used, or a mixture of polymers having one or more of these structural units may be used.

(A-1) The component can be obtained by polymerizing the monomers that induce each constituent unit by a conventional method, for example, a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN).

(A-1) The mass average molecular weight (converted to polystyrene by gel permeation chromatography (GPC), the same applies hereinafter) of the component is preferably 5,000 to 30,000, more preferably 15,000 to 25,000. When the mass average molecular weight is 30,000 or less, the resolution is high and is particularly preferable for thin film implantation. Furthermore, when it is 5,000 or more, the heat resistance is high and is particularly preferable for thin film implantation.

In addition, the smaller the dispersion (Mw/Mn (number average molecular weight)) of the resin component (A-1) (closer to monodispersion), the better the resolution, which is preferable. The dispersion is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.0 to 2.5.

The following (A-2) components are described in detail.

constituent unit (a4)

The constituent unit (a4) is a constituent unit containing an acid-decomposable group whose polarity increases by the action of an acid.

An "acid-decomposable group" is a group having acid-decomposability in which at least a part of the bonds in the acid-decomposable group structure can be cleaved by the action of an acid. As an acid-decomposable group whose polarity increases by the action of an acid, a group that is decomposed by the action of an acid to generate a polar group can be exemplified. At this time, as a polar group, a carboxyl group, a hydroxyl group, an amino group, a sulfo group (-SO ₃ H) can be exemplified. Among these, a sulfo group or a polar group containing -OH in the structure (OH-containing polar group) is preferable, a sulfo group or a carboxyl group or a hydroxyl group is preferable, and a carboxyl group or a hydroxyl group is particularly preferable.

More specifically, as an acid-decomposable group whose polarity increases by the action of an acid, a group in which the polar group is protected by an acid-dissociable group (for example, a group in which a hydrogen atom of an OH-containing polar group is protected by an acid-dissociable group) can be mentioned. The acid-dissociable group constituting the acid-decomposable group needs to be a group having lower polarity than a polar group generated by dissociation of the acid-dissociable group, and thus, when the acid-dissociable group is dissociated by the action of an acid, a polar group having higher polarity than the acid-dissociable group is generated, thereby increasing the polarity. As a result, the polarity of the entire component (A-2) increases. As a result of the increase in polarity, the solubility in a developer relatively changes, and when the developer is an organic developer, the solubility decreases. The acid-dissociable group is not particularly limited, and those proposed so far as acid-dissociable groups of base resins for chemically amplified resists can be used.

As the structural unit (a4), a structural unit derived from an acrylic acid ester in which the hydrogen atom bonded to the carbon atom at the α position may be substituted with a substituent is preferable.

“Structure unit derived from acrylic acid ester” means a structure unit formed by cleavage of the ethylenic double bond of acrylic acid ester.

“Acrylic acid ester” is a compound in which the hydrogen atom at the carboxyl terminal of acrylic acid (CH ₂ = CH-COOH) is replaced with an organic group.

The hydrogen atom bonded to the carbon atom at the α-position of the acrylic acid ester may be replaced by a substituent. The substituent (R ^α ) replacing the hydrogen atom bonded to the carbon atom at the α-position is an atom or group other than a hydrogen atom, and examples thereof include an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, a hydroxyalkyl group, etc. In addition, the carbon atom at the α-position of the acrylic acid ester refers to a carbon atom to which a carbonyl group is bonded, unless otherwise specified.

Hereinafter, an acrylic acid ester in which the hydrogen atom bonded to the carbon atom at the α position is substituted with a substituent is sometimes called an α-substituted acrylic acid ester. In addition, an acrylic acid ester and an α-substituted acrylic acid ester are sometimes collectively called an "(α-substituted) acrylic acid ester."

As a constituent unit (a4), a constituent unit represented by the following formula (a4-1) or (a4-2) can be exemplified.

[Chemical formula 6]

[During the meal,

R is a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms that can be substituted with a halogen atom.

Va ¹ is a divalent hydrocarbon group that may have an ether bond, a urethane bond, or an amide bond.

n _a1 is 0~2.

Ra ¹ is an acid-labile group represented by the following formula (a4-r-1) or (a4-r-2).

Wa ¹ is a hydrocarbon group with a valence of n _a2 +1.

n _a2 is 1~3.

Ra ² is an acid-labile group represented by the following formula (a4-r-1) or (a4-r-3).]

In formula (a4-1), R can be a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.

The alkyl group of R having 1 to 5 carbon atoms is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, and specific examples thereof 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 the like.

The halogenated alkyl group having 1 to 5 carbon atoms of R is a group in which some or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are replaced with halogen atoms. At this time, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like, and a fluorine atom is particularly preferred. That is, the halogenated alkyl group is preferably a fluorinated alkyl group.

As for R, a hydrogen atom or a methyl group is most preferable because they are easily available industrially.

In formula (a4-1), Va ¹ includes a case where the above two hydrocarbon groups are bonded via an ether bond, a urethane bond, or an amide bond.

The hydrocarbon group of Va ¹ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group as the divalent hydrocarbon group in Va ¹ may be saturated or unsaturated, and is usually preferably saturated. More specifically, the aliphatic hydrocarbon group may include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in its structure, and the like.

The above linear or branched aliphatic hydrocarbon preferably has 1 to 10 carbon atoms, more preferably 1 to 6, still more preferably 1 to 4, and most preferably 1 to 3.

As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable, and specific examples thereof include a methylene group [-CH ₂ -], an ethylene group [-(CH ₂ ) ₂ -], a trimethylene group [-(CH ₂ ) ₃ -], a tetramethylene group [-(CH ₂ ) ₄ -], a pentamethylene group [-(CH ₂ ) ₅ -], etc.

As the branched-chain aliphatic hydrocarbon group, a branched-chain alkylene group is preferable, and specifically, alkylmethylene groups such as -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 CH ₃ ) ₂ -CH ₂ -; Examples thereof include alkyltrimethylene groups such as -CH(CH ₃ )CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ -; alkylalkylene groups such as alkyltetramethylene groups such as -CH(CH ₃ )CH ₂ CH ₂ CH ₂ -, -CH ₂ CH(CH ₃ )CH ₂ CH ₂ -; and the like. As the alkyl group in the alkylalkylene group, a linear alkyl group having 1 to 5 carbon atoms is preferable.

Examples of the aliphatic hydrocarbon group containing a ring in the above structure include an alicyclic hydrocarbon group (a group in which two hydrogen atoms are removed from an aliphatic hydrocarbon ring), a group in which an alicyclic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, a group in which an alicyclic hydrocarbon group is interposed in the middle of a linear or branched aliphatic hydrocarbon group, etc. Examples of the linear or branched aliphatic hydrocarbon group include the same groups as described above.

The above-mentioned alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably has 3 to 12 carbon atoms.

The above alicyclic hydrocarbon group may be polycyclic or monocyclic. As the monocyclic alicyclic hydrocarbon group, a group obtained by removing two hydrogen atoms from a monocycloalkane is preferable. The monocycloalkane is preferably one having 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. As the polycyclic alicyclic hydrocarbon group, a group obtained by removing two hydrogen atoms from a polycycloalkane is preferable, and the polycycloalkane is preferably one having 7 to 12 carbon atoms, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

The aromatic hydrocarbon group as the divalent hydrocarbon group in the above Va ¹ preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, still more preferably 5 to 20 carbon atoms, particularly preferably 6 to 15 carbon atoms, and most preferably 6 to 10 carbon atoms. However, the carbon atoms in the substituent are excluded from the carbon atoms in the substituent.

As an aromatic ring possessed by an aromatic hydrocarbon group, specific examples thereof include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are replaced with heteroatoms; and the like. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom.

Specific examples of the aromatic hydrocarbon group include a group in which two hydrogen atoms are removed from the aromatic hydrocarbon ring (arylene group); a group in which one of the hydrogen atoms of the group in which one hydrogen atom is removed from the aromatic hydrocarbon ring (aryl group) is substituted with an alkylene group (for example, a group in which one hydrogen atom is additionally removed from the aryl group in an arylalkyl group such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, or a 2-naphthylethyl group); and the like. The alkylene group (the alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 to 2, and particularly preferably 1.

In equation (a4-1), Ra ¹ As an acid-dissociating group, for example, an acid-dissociating group represented by the following formula (a4-r-1) (hereinafter, for convenience, sometimes referred to as an “acetal-type acid-dissociating group”) can be mentioned.

[Chemical formula 7]

[During the meal,

Ra' ¹ , Ra' ² are hydrogen atoms or alkyl groups.

Ra' ³ may be a hydrocarbon group, or may be combined with either Ra' ¹ or Ra' ² to form a ring.

* indicates a combined hand.]

In formula (a4-r-1), the alkyl group of Ra' ¹ and Ra' ² may be the same as the alkyl group exemplified as a substituent capable of bonding to the carbon atom at the α position in the description of the α-substituted acrylic acid ester, and a methyl group or an ethyl group is preferable, and a methyl group is most preferable.

In the formula (a4-r-1), the hydrocarbon group of Ra' ³ is preferably an alkyl group having 1 to 20 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms; a linear or branched alkyl group is preferable, and specific examples thereof 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, a 1,1-dimethylethyl group, a 1,1-diethylpropyl group, a 2,2-dimethylpropyl group, a 2,2-dimethylbutyl group, and the like.

When Ra' ³ is a cyclic hydrocarbon group, it may be aliphatic or aromatic, and may be polycyclic or monocyclic. As the monocyclic alicyclic hydrocarbon group, a group obtained by removing one hydrogen atom from a monocycloalkane is preferable. As the monocycloalkane, a group having 3 to 8 carbon atoms is preferable, and specific examples thereof include cyclopentane, cyclohexane, and cyclooctane. As the polycyclic alicyclic hydrocarbon group, a group obtained by removing one hydrogen atom from a polycycloalkane is preferable, and as the polycycloalkane, a group having 7 to 12 carbon atoms is preferable, and specific examples thereof include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.

When Ra' ³ is an aromatic hydrocarbon group, specific examples of the included aromatic ring include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; aromatic heterocycles in which some of the carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms; etc. Examples of the heteroatom in the aromatic heterocycle include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic hydrocarbon group include a group in which one hydrogen atom is removed from the aromatic hydrocarbon ring (aryl group); a group in which one of the hydrogen atoms of the aryl group is substituted with an alkylene group (for example, arylalkyl groups such as a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, and a 2-naphthylethyl group); etc. The number of carbon atoms in the above alkylene group (alkyl chain in the arylalkyl group) is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

When Ra' ³ combines with either Ra' ¹ or Ra' ² to form a ring, the ring group is preferably a 4 to 7-membered ring, and more preferably a 4 to 6-membered ring. Specific examples of the ring group include a tetrahydropyranyl group, a tetrahydrofuranyl group, and the like.

Among the acid-dissociable groups in formula (a4-1), examples of the acid-dissociable group of Ra ¹ include an acid-dissociable group represented by the following formula (a4-r-2).

[Chemical formula 8]

[During the meal,

Ra' ⁴ ~Ra' ⁶ are hydrocarbon groups.

Ra' ⁵ and Ra' ⁶ can combine with each other to form a ring.

* indicates a combined hand.]

As the hydrocarbon group of Ra' ⁴ to Ra' ⁶ , the same groups as those of Ra' ³ can be mentioned. Ra' ⁴ is preferably an alkyl group having 1 to 10 carbon atoms, and is more preferably an alkyl group having 1 to 5 carbon atoms. When Ra' ⁵ and Ra' ⁶ are bonded to each other to form a ring, a group represented by the following formula (a4-r2-1) can be mentioned.

Meanwhile, when Ra' ⁴ to Ra' ⁶ are independent hydrocarbon groups that are not bonded to each other, a group represented by the following formula (a4-r2-2) can be mentioned.

[Chemical formula 9]

[During the meal,

Ra' ¹⁰ is an alkyl group with 1 to 10 carbon atoms.

Ra' ¹¹ is a group that forms an aliphatic ring group together with the carbon atom to which Ra' ¹⁰ is bonded.

Ra' ¹² ~Ra' ¹⁴ each independently represent a hydrocarbon group.

* indicates a combined hand.]

In formula (a4-r2-1), the alkyl group of the alkyl group having 1 to 10 carbon atoms of Ra' ¹⁰ is preferably a group exemplified as a linear or branched alkyl group of Ra' ³ in formula (a4-r-1).

Among the formulas (a4-r2-1), the aliphatic cyclic group constituted by Ra' ¹¹ is preferably a group exemplified as the cyclic alkyl group of Ra' ³ in formula (a4-r-1).

In formula (a4-r2-2), it is preferable that Ra' ¹² and Ra' ¹⁴ are each independently an alkyl group having 1 to 10 carbon atoms, and the alkyl group is more preferably a group exemplified as a linear or branched alkyl group of Ra' ³ in formula (a4-r-1), is further preferably a linear alkyl group having 1 to 5 carbon atoms, and is particularly preferably a methyl group or an ethyl group.

In formula (a4-r2-2), Ra' ¹³ is preferably a linear, branched or cyclic alkyl group exemplified as a hydrocarbon group of Ra' ³ in formula (a4-r-1). Among these, a group exemplified as a cyclic alkyl group of Ra' ³ is more preferable.

In formula (a4-2), the hydrocarbon group of n _a2 +1 of Wa ¹ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic hydrocarbon group means a hydrocarbon group that does not have aromaticity, and may be saturated or unsaturated, and is usually preferably saturated. Examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in its structure, or a group combining a linear or branched aliphatic hydrocarbon group and an aliphatic hydrocarbon group containing a ring in its structure, and specifically, examples thereof include the same groups as Va ¹ in formula (a4-1) described above.

In formula (a4-2), Ra ² may be an acid-labile group represented by formula (a4-r-1) defined in the above Ra ¹ .

Alternatively, Ra ² in formula (a4-2) may be an acid-dissociable group represented by (a4-r-3) below (hereinafter, for convenience, sometimes referred to as a “tertiary alkyloxycarbonyl acid-dissociable group”).

[Chemical Formula 10]

[During the meal,

Ra' ⁷ ~Ra' ⁹ represent alkyl groups.

* indicates a combined hand.]

In the formula (a4-r-3), Ra' ⁷ to Ra' ⁹ are preferably alkyl groups having 1 to 5 carbon atoms, more preferably alkyl groups having 1 to 3 carbon atoms. In addition, the total number of carbon atoms of each alkyl group is preferably 3 to 7, more preferably 3 to 5, and most preferably 3 to 4.

Specific examples of the above formulas (a4-1) and (a4-2) are shown in the following chemical formulas 11 and 12. In each of the formulas below, R ⁰ represents a hydrogen atom, a methyl group, or a trifluoromethyl group.

[Chemical Formula 11]

[Chemical Formula 12]

(A-2) When the component contains the structural unit (a4), the proportion of the structural unit (a4) is preferably 20 to 80 mol%, more preferably 20 to 75 mol%, and even more preferably 25 to 70 mol%, relative to the total structural units constituting the (A-2) component. By setting it to the lower limit or higher, lithography characteristics such as sensitivity, resolution, and LWR are also improved. In addition, by setting it to the upper limit or lower, a balance with other structural units can be achieved.

constituent unit (a5)

The constituent unit (a5) may contain a constituent unit (a5) having a -SO ₂ - containing cyclic group, a lactone containing cyclic group, a carbonate containing cyclic group, or a heterocyclic group other than these.

The -SO ₂ -containing cyclic group, the lactone-containing cyclic group, the carbonate-containing cyclic group or a heterocyclic group other than these in the composition unit (a5) is effective in increasing the adhesion of the resist film to the substrate when the (A-2) component is used to form the resist film.

In addition, when the aforementioned structural unit (a4) has a -SO ₂ - containing cyclic group, a lactone containing cyclic group, a carbonate containing cyclic group or a heterocyclic group other than these in its structure, the structural unit also corresponds to the structural unit (a5), but such a structural unit corresponds to the structural unit (a4) and does not correspond to the structural unit (a5).

It is preferable that the constituent unit (a5) is a constituent unit represented by the following formula (a5-1).

[Chemical Formula 13]

[During the meal,

R is a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a halogenated hydrocarbon group having 1 to 10 carbon atoms.

Ya ²¹ is a single bond, or a divalent linker.

La ²¹ is -O-, -COO-, -CON(R')-, -OCO-, -CONHCO- or -CONHCS-, and R' represents a hydrogen atom or a methyl group. However, when La ²¹ is -O-, Ya ²¹ cannot be -CO-.

Ra ²¹ is a -SO ₂ - containing cyclic group, a lactone containing cyclic group, a carbonate containing cyclic group, or a heterocyclic group other than these.]

In formula (a5-1), Ra ²¹ The "-SO ₂ -containing cyclic group" of this refers to a cyclic group containing a ring containing -SO ₂ - in its ring skeleton, and specifically, it is a cyclic group in which the sulfur atom (S) in -SO ₂ - forms a part of the ring skeleton of the cyclic group. The ring containing -SO ₂ - in the ring skeleton is counted as the first ring, and if it is the only ring, it is called a monocyclic group, and if it additionally has another ring structure, it is called a polycyclic group regardless of the structure. The -SO ₂ -containing cyclic group may be monocyclic or polycyclic.

Ra ²¹ The "lactone-containing cyclic group" of the present invention refers to a cyclic group containing a ring (lactone ring) containing -OC(=O)- in its ring skeleton. When the lactone ring is counted as the first ring, if it is only a lactone ring, it is called a monocyclic group, and if it additionally has another ring structure, it is called a polycyclic group regardless of the structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group. The lactone-containing cyclic group is not particularly limited, and any one can be used. Specifically, groups represented by the following formulae (a5-r-1) to (a5-r-7) can be mentioned.

[Chemical Formula 14]

[During the meal,

Ra' ²¹ is each independently a hydrogen atom, an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, -COOR", -OC(=O)R", a hydroxyalkyl group, or a cyano group.

"R" is a hydrogen atom or an alkyl group.

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.

n' is an integer from 0 to 2.

m' is 0 or 1.

* indicates a combined hand.]

Ra ²¹ The "carbonate-containing cyclic group" of this term refers to a cyclic group containing a ring (carbonate ring) containing -OC(=O)-O- in its ring skeleton. When the carbonate ring is counted as the first ring, if it is only a carbonate ring, it is called a monocyclic group, and if it additionally has another ring structure, it is called a polycyclic group regardless of the structure. The carbonate-containing cyclic group may be a monocyclic group or a polycyclic group.

The "heterocyclic group" of Ra ²¹ refers to a cyclic group containing one or more atoms other than carbon in addition to carbon, and examples thereof include a heterocyclic group or a nitrogen-containing heterocyclic group. As the nitrogen-containing heterocyclic group, a cycloalkyl group having 3 to 8 carbon atoms which may be substituted with one or two oxo groups can be exemplified. Preferred examples of the cycloalkyl group include 2,5-dioxopyrrolidine and 2,6-dioxopiperidine.

(A-2) When the component contains the structural unit (a5), the proportion of the structural unit (a5) is preferably 1 to 80 mol%, more preferably 5 to 70 mol%, still more preferably 10 to 65 mol%, and particularly preferably 10 to 60 mol%, relative to the total of all structural units constituting the (A-2) component. By setting it to the lower limit or more, the effect of containing the structural unit (a5) can be sufficiently obtained, and by setting it to the upper limit or less, a balance with other structural units can be maintained, and various lithography characteristics and pattern shapes become good.

constituent unit (a6)

The constituent unit (a6) is a constituent unit containing an aliphatic hydrocarbon group containing a polar group (except for the constituent units (a4) and (a5) described above). It is thought that since the (A-2) component has the constituent unit (a6), the hydrophilicity of the (A-2) component increases, contributing to the improvement of resolution.

Examples of the above polar group include a hydroxyl group, a cyano group, a carboxyl group, a fluorinated hydroxyalkyl group in which some of the hydrogen atoms of an alkyl group are replaced with fluorine atoms, and a hydroxyl group is particularly preferable.

As the aliphatic hydrocarbon group, a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) or a cyclic aliphatic hydrocarbon group (cyclic group) can be exemplified. The cyclic group may be a monocyclic group or a polycyclic group, and can be appropriately selected and used from among many proposed ones, for example, in a resin for a resist composition for an ArF excimer laser. The cyclic group is preferably a polycyclic group, and one having 7 to 30 carbon atoms is more preferable.

Among these, a structural unit derived from an acrylic acid ester containing an aliphatic polycyclic group containing a fluorinated hydroxyalkyl group in which some of the hydrogen atoms of a hydroxyl group, a cyano group, a carboxyl group, or an alkyl group are replaced with fluorine atoms is more preferable. As the polycyclic group, a group in which two or more hydrogen atoms are removed from a bicycloalkane, a tricycloalkane, a tetracycloalkane, etc. can be exemplified. Specifically, a group in which two or more hydrogen atoms are removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane can be exemplified. Among these polycyclic groups, a group in which two or more hydrogen atoms are removed from adamantane, a group in which two or more hydrogen atoms are removed from norbornane, and a group in which two or more hydrogen atoms are removed from tetracyclododecane are industrially preferable.

As a structural unit (a6), a structural unit derived from an acrylic acid ester in which the hydrogen atom bonded to the carbon atom at the α position may be substituted with a substituent and which contains an aliphatic hydrocarbon group containing a polar group is preferable.

As the structural unit (a6), when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to 10 carbon atoms, a structural unit derived from hydroxyethyl ester of acrylic acid is preferable, and when the hydrocarbon group is a polycyclic group, a structural unit represented by the following formula (a6-1), a structural unit represented by the formula (a6-2), and a structural unit represented by the formula (a6-3) are preferable.

[Chemical Formula 15]

[During the meal,

R is a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms that can be substituted with a halogen atom.

j is an integer from 1 to 3, k is an integer from 1 to 3, t' is an integer from 1 to 3, l is an integer from 1 to 5, and s is an integer from 1 to 3.]

(A-2) The composition unit (a6) contained in the component may be one type or two or more types.

(A-2) Among the components, the proportion of the structural unit (a6) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, and even more preferably 5 to 25 mol%, relative to the total of all structural units constituting the resin component (A-2). By setting the proportion of the structural unit (a6) to the lower limit or more, the effect of containing the structural unit (a6) can be sufficiently obtained, and by setting it to the upper limit or less, it becomes easy to maintain a balance with other structural units.

(A-2) It is preferable that the component has (a4), it is more preferable that it is a copolymer having (a4) and (a5), and it is particularly preferable that it is a copolymer having (a4), (a5) and (a6).

(A-2) Component may be used alone or in combination of two or more. The proportion of component (A-2) in the resin (A) component is preferably 25 mass% or more, more preferably 50 mass%, even more preferably 75 mass%, and may be 100 mass% with respect to the total mass of component (A-2). When the proportion is 25 mass% or more, the lithography characteristics are further improved. In the present invention, the content of component (A-2) may be adjusted according to the resist film thickness to be formed, etc.

<(B) Component>

(B) As a component, there is no particular limitation, and any of those proposed so far as acid generators for chemically amplified resists can be used.

As such acid generators, a variety of types have been known so far, including onium salt-based acid generators such as iodonium salts or sulfonium salts, oxime sulfonate-based acid generators, diazomethane-based acid generators such as bisalkyl or bisarylsulfonyldiazomethanes, and poly(bissulfonyl)diazomethanes, nitrobenzylsulfonate-based acid generators, iminosulfonate-based acid generators, and disulfone-based acid generators.

As an onium salt-based acid generator, a compound represented by the following formula (b-1) or (b-2) can be mentioned.

[Chemical Formula 16]

[During the meal,

R ^1" to R ^3" , R ^5" to R ^6" are each independently an aryl group or an alkyl group.

R ^4" is a linear, branched, or cyclic alkyl group, wherein some or all of the hydrogen atoms of the alkyl group may be replaced with fluorine.

At least one of R ^1" to R ^3" is an aryl group.

At least one of R ^5" to R ^6" is an aryl group.]

In formula (b-1), the aryl group of R ^1" to R ^3" is not particularly limited, and is, for example, an aryl group having 6 to 20 carbon atoms, wherein some or all of the hydrogen atoms of the aryl group may be substituted with an alkyl group, an alkoxy group, a halogen atom, or the like, or may be unsubstituted. As the aryl group, an aryl group having 6 to 10 carbon atoms is preferable in that it can be synthesized inexpensively. Specific examples thereof include a phenyl group and a naphthyl group. As the alkyl group where the hydrogen atoms of the aryl group may be substituted, an alkyl group having 1 to 5 carbon atoms is preferable, and a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group is most preferable. As the alkoxy group where the hydrogen atoms of the aryl group may be substituted, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group or an ethoxy group is most preferable. As the halogen atom that may be substituted for the hydrogen atom of the above aryl group, it is preferable that it be a fluorine atom.

There is no particular limitation on the alkyl group of R ^1" to R ^3" , and examples thereof include linear, branched, or cyclic alkyl groups having 1 to 10 carbon atoms. In view of excellent resolution, those having 1 to 5 carbon atoms are preferable. Specifically, methyl groups, ethyl groups, n-propyl groups, isopropyl groups, n-butyl groups, isobutyl groups, n-pentyl groups, cyclopentyl groups, hexyl groups, cyclohexyl groups, nonyl groups, decanyl groups, etc. A methyl group is preferable in view of excellent resolution and low-cost synthesis.

Among R ^1" to R ^3" , it is preferable that two or more are aryl groups, it is more preferable that all of R ^1" to R ^3" are aryl groups, and among these, it is most preferable that all of R ^1" to R ^3" are phenyl groups.

In formula (b-1), the linear alkyl group of R ^4" is preferably one having 1 to 10 carbon atoms, more preferably one having 1 to 8 carbon atoms, and most preferably one having 1 to 4 carbon atoms.

As for the cyclic alkyl group of R ^4" , one having 4 to 15 carbon atoms is preferable, one having 4 to 10 carbon atoms is more preferable, and one having 6 to 10 carbon atoms is most preferable.

In the alkyl group of "R ^4" , when some or all of the hydrogen atoms are replaced with fluorine, that is, the fluorinated alkyl group is preferably one having 1 to 10 carbon atoms, more preferably one having 1 to 8 carbon atoms, and most preferably one having 1 to 4 carbon atoms. In addition, the fluorination rate (ratio of fluorine atoms in the alkyl group) of the fluorinated alkyl group is preferably 10 to 100%, more preferably 50 to 100%, and in particular, it is preferable that all of the hydrogen atoms are replaced with fluorine atoms because this increases the acid strength.

It is most preferable that R ^4" is a linear or cyclic alkyl group, or a fluorinated alkyl group.

In formula (b-2), R ^4" may be the same as R ^1" of formula (b-1).

In formula (b-2), the aryl group of R ^5" to R ^6" includes the same groups as the aryl groups of R ^1" to R ^3" . The alkyl group of R ^5" to R ^6" includes the same groups as the alkyl groups of R ^1" to R ^3" .

Among R ^5" to R ^6" , it is preferable that two or more are aryl groups, and it is more preferable that all of R ^5" to R ^6" are aryl groups. Among these, it is most preferable that all of R ^5" to R ^6" are phenyl groups.

Specific examples of onium salt-based acid generators include trifluoromethanesulfonate or nonafluorobutanesulfonate of diphenyliodonium, trifluoromethanesulfonate or nonafluorobutanesulfonate of bis(4-tert-butylphenyl)iodonium, trifluoromethanesulfonate of triphenylsulfonium, its heptafluoropropanesulfonate, its camphorsulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of tri(4-methylphenyl)sulfonium, its heptafluoropropanesulfonate, its camphorsulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of dimethyl(4-hydroxynaphthyl)sulfonium, its heptafluoropropanesulfonate, its camphorsulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of monophenyldimethylsulfonium, its heptafluoropropanesulfonate, its Camphorsulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of diphenylmonomethylsulfonium, its heptafluoropropanesulfonate, its camphorsulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of (4-methylphenyl)diphenylsulfonium, its heptafluoropropanesulfonate, its camphorsulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of (4-methoxyphenyl)diphenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of tri(4-tert-butyl)phenylsulfonium, its heptafluoropropanesulfonate, its camphorsulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of diphenyl(1-(4-methoxy)naphthyl)sulfonium, its heptafluoropropanesulfonate, its Examples thereof include camphorsulfonate or its nonafluorobutanesulfonate. In addition, onium salts in which the anion portion of these onium salts is substituted with methanesulfonate, n-propanesulfonate, n-butanesulfonate, or n-octanesulfonate can also be used.

In addition, in the above formula (b-1) or (b-2), a compound in which the anion moiety is replaced with an anion moiety represented by the following formula (b-3) or (b-4) can also be used (the cation moiety is the same as (b-1) or (b-2)).

[Chemical Formula 17]

[During the meal,

X" is an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is replaced with a fluorine atom.

Y" and Z" are each independently an alkyl group having 1 to 10 carbon atoms in which at least one hydrogen atom is replaced by a fluorine atom.]

In formula (b-3), X" preferably has 3 to 5 carbon atoms, and most preferably has 3 carbon atoms.

In formula (b-3), the number of carbon atoms in the alkyl groups of Y" and Z" is each independently 1 to 10, preferably 1 to 7 carbon atoms, and more preferably 1 to 3 carbon atoms.

The number of carbon atoms in the alkylene group of "X" or "Y", "Z" The carbon number of the alkyl group is preferably smaller within the above range of carbon numbers for reasons such as better solubility in a resist solvent.

Also, X" In the alkylene group of or the alkyl group of Y", Z", the greater the number of hydrogen atoms substituted with fluorine atoms, the stronger the acid strength becomes, and also the transparency to high-energy light or electron beams having a wavelength of 200 nm or less improves, which is preferable. The ratio of fluorine atoms in the alkylene group or alkyl group, i.e., the fluorination rate, is preferably 70 to 100%, more preferably 90 to 100%, and most preferably, it is a perfluoroalkylene group or a perfluoroalkyl group in which all hydrogen atoms are substituted with fluorine atoms.

In the present invention, the oxime sulfonate acid generator is a compound having at least one group represented by the following formula (b-5) and having the property of generating an acid upon irradiation with radiation. Such an oxime sulfonate acid generator can be arbitrarily selected and used among those proposed for use in chemically amplified resist compositions.

[Chemical Formula 18]

[During the meal

R ²¹ and R ²² each independently represent an organic group]

In the present invention, an “organic group” is a group containing a carbon atom, and may have atoms other than carbon atoms (e.g., a hydrogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, a halogen atom (a fluorine atom, a chlorine atom, etc.)).

In formula (b-5), the organic group of R ²¹ is preferably a linear, branched or cyclic alkyl group or aryl group. These alkyl groups and aryl groups may have a substituent. There is no particular limitation on the substituent, and examples thereof include a fluorine atom, a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, and the like. Here, “having a substituent” means that some or all of the hydrogen atoms of the alkyl group or aryl group are substituted with a substituent.

As the alkyl group of R ²¹ , one having 1 to 20 carbon atoms is preferable, more preferably 1 to 10 carbon atoms, still more preferably 1 to 8 carbon atoms, particularly preferably 1 to 6 carbon atoms, and most preferably 1 to 4 carbon atoms. As the alkyl group, a partially or fully halogenated alkyl group (hereinafter, sometimes referred to as a halogenated alkyl group) is particularly preferable. In addition, a partially halogenated alkyl group means an alkyl group in which some of the hydrogen atoms are replaced with halogen atoms, and a fully halogenated alkyl group means an alkyl group in which all of the hydrogen atoms are replaced with halogen atoms. 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 of R ²¹ 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 fully halogenated aryl group is particularly preferable. In addition, a partially halogenated aryl group means an aryl group in which some of the hydrogen atoms are replaced with halogen atoms, and a fully halogenated aryl group means an aryl group in which all of the hydrogen atoms are replaced with halogen atoms.

As R ²¹ , an alkyl group having 1 to 4 carbon atoms and not particularly having a substituent, or a fluorinated alkyl group having 1 to 4 carbon atoms is preferable.

In formula (b-5), the organic group of R ²² is preferably a linear, branched or cyclic alkyl group, aryl group or cyano group. The alkyl group and aryl group of R ²² include the same groups as the alkyl groups and aryl groups exemplified for R ²¹ above.

As R ²² , a cyano group, an alkyl group having 1 to 8 carbon atoms without a substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms is particularly preferable.

As an oxime sulfonate-based acid generator, a more preferable one is a compound represented by the following formula (b-6) or (b-7).

[Chemical Formula 19]

[During the meal,

R ³¹ is a cyano group, an alkyl group having no substituent, or a halogenated alkyl group.

R ³² is an aryl group.

R ³³ is an alkyl group or a halogenated alkyl group having no substituent.]

[Chemical formula 20]

[During the meal,

R ³⁴ is a cyano group, an alkyl group having no substituent, or a halogenated alkyl group.

R ³⁵ is a di- or trivalent aromatic hydrocarbon group.

R ³⁶ is an alkyl group or a halogenated alkyl group having no substituent.

p is 2 or 3.]

In formula (b-6), the alkyl group or halogenated alkyl group not having a substituent of R ³¹ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.

For R ³¹ , a halogenated alkyl group is preferred, and a fluorinated alkyl group is more preferred.

In the fluorinated alkyl group in R ³¹ , it is preferable that 50% or more of the hydrogen atoms of the alkyl group are fluorinated, more preferably 70% or more, and even more preferably 90% or more.

In formula (b-6), examples of the aryl group for R ³² include groups in which 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 anthracyl group, and a phenanthryl group, and heteroaryl groups in which some of the carbon atoms constituting the ring of these groups are replaced with heteroatoms such as an oxygen atom, a sulfur atom, and a nitrogen atom. Among these, a fluorenyl group is preferable.

The aryl group of R ³² 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 has 1 to 4 carbon atoms. In addition, it is preferable that the halogenated alkyl group is a fluorinated alkyl group.

In formula (b-7), the alkyl group or halogenated alkyl group not having a substituent of R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.

For R ³³ , a halogenated alkyl group is preferred, a fluorinated alkyl group is more preferred, and a partially fluorinated alkyl group is most preferred.

The fluorinated alkyl group in R ³³ is preferably one in which 50% or more of the hydrogen atoms of the alkyl group are fluorinated, more preferably 70% or more, and even more preferably 90% or more, because this increases the strength of the acid generated. Most preferably, it is a completely fluorinated alkyl group in which 100% of the hydrogen atoms are substituted with fluorine.

In formula (b-7), the alkyl group or halogenated alkyl group having no substituent of R ³⁴ may be the same as the alkyl group or halogenated alkyl group having no substituent of R ³¹ .

In formula (b-7), the aromatic hydrocarbon group having 2 or 3 valences of R ³⁵ may be a group in which 1 or 2 hydrogen atoms are additionally removed from the aryl group of R ³² .

As the alkyl group or halogenated alkyl group having no substituent of R ³⁶ , the same ones as the alkyl group or halogenated alkyl group having no substituent of R ³³ can be exemplified.

p is preferably 2.

Specific examples of oxime sulfonate acid generators include α-(p-toluenesulfonyloxyimino)-benzylcyanide, α-(p-chlorobenzenesulfonyloxyimino)-benzylcyanide, α-(4-nitrobenzenesulfonyloxyimino)-benzylcyanide, α-(4-nitro-2-trifluoromethylbenzenesulfonyloxyimino)-benzylcyanide, α-(benzenesulfonyloxyimino)-4-chlorobenzylcyanide, α-(benzenesulfonyloxyimino)-2,4-dichlorobenzylcyanide, α-(benzenesulfonyloxyimino)-2,6-dichlorobenzylcyanide, α-(benzenesulfonyloxyimino)-4-methoxybenzylcyanide, 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-thienylcyanide, α-(methylsulfonyloxyimino)-1-cyclopentenylacetonitrile, α-(methylsulfonyloxyimino)-1-cyclohexenylacetonitrile, α-(Methylsulfonyloxyimino)-1-cycloheptenylacetonitrile, α-(Methylsulfonyloxyimino)-1-cyclooctenylacetonitrile, α-(Trifluoromethylsulfonyloxyimino)-1-cyclopentenylacetonitrile, α-(Trifluoromethylsulfonyloxyimino)-cyclohexylacetonitrile, α-(Ethylsulfonyloxyimino)-ethylacetonitrile, α-(Propylsulfonyloxyimino)-propylacetonitrile, α-(Cyclohexylsulfonyloxyimino)-cyclopentylacetonitrile, α-(Cyclohexylsulfonyloxyimino)-cyclohexylacetonitrile, α-(Cyclohexylsulfonyloxyimino)-1-cyclopentenylacetonitrile, α-(Ethylsulfonyloxyimino)-1-cyclopentenylacetonitrile, α-(isopropylsulfonyloxyimino)-1-cyclopentenylacetonitrile, 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, Examples thereof include α-(trifluoromethylsulfonyloxyimino)-phenylacetonitrile, α-(trifluoromethylsulfonyloxyimino)-p-methoxyphenylacetonitrile, α-(ethylsulfonyloxyimino)-p-methoxyphenylacetonitrile, α-(propylsulfonyloxyimino)-p-methylphenylacetonitrile, and α-(methylsulfonyloxyimino)-p-bromophenylacetonitrile.

In addition, as a specific example of an oxime sulfonate-based acid generator, a compound represented by the following chemical formula can be mentioned.

[Chemical Formula 21]

In addition, among the compounds represented by the above formula (b-6) or formula (b-7), examples of preferred compounds are shown below.

[Chemical Formula 22]

[Chemical Formula 23]

Among diazomethane acid generators, specific examples of bisalkyl or bisarylsulfonyl diazomethanes include bis(isopropylsulfonyl)diazomethane, bis(p-toluenesulfonyl)diazomethane, bis(1,1-dimethylethylsulfonyl)diazomethane, bis(cyclohexylsulfonyl)diazomethane, and bis(2,4-dimethylphenylsulfonyl)diazomethane.

In addition, as poly(bissulfonyl)diazomethanes, for example, having the structures shown below, 1,3-bis(phenylsulfonyldiazomethylsulfonyl)propane (in the case of A=3), 1,4-bis(phenylsulfonyldiazomethylsulfonyl)butane (in the case of A=4), 1,6-bis(phenylsulfonyldiazomethylsulfonyl)hexane (in the case of A=6), 1,10-bis(phenylsulfonyldiazomethylsulfonyl)decane (in the case of A=10), 1,2-bis(cyclohexylsulfonyldiazomethylsulfonyl)ethane (in the case of B=2), 1,3-bis(cyclohexylsulfonyldiazomethylsulfonyl)propane (in the case of B=3), 1,6-bis(cyclohexylsulfonyldiazomethylsulfonyl)hexane (in the case of B=6), Examples include 1,10-bis(cyclohexylsulfonyldiazomethylsulfonyl)decane (where B=10).

[Chemical Formula 24]

(B) As a component, one of these acid generators may be used alone, or two or more may be used in combination.

The content of component (B) in the resist composition of the present invention is 0.5 to 30 parts by mass, preferably 1 to 10 parts by mass, per 100 parts by mass of component (A). By setting it within the above range, pattern formation is sufficiently carried out. In addition, it is preferable because a uniform solution is obtained and the storage stability is improved.

<(C) Component>

(C) Component is a compound having radiation absorption capability. As for (C), it is preferable that the component has absorption capability in the wavelength band of radiation used for exposure, and in particular, can reduce pattern dimension changes caused by SW generated by reflection from the substrate or diffuse reflection caused by steps on the substrate surface.

Specifically, examples thereof include compounds having absorption capability at 248 nm, which is the wavelength of a KrF excimer laser, or 193 nm, which is the wavelength of an ArF excimer laser, and include low-molecular-weight compounds such as dyes and high-molecular-weight compounds such as resins.

(C) Specifically, as a component, a compound represented by the following formula (1) can be mentioned.

[Chemical Formula 25]

Equation (1)

[During the meal,

R ₁ and R ₂ are each independently a hydrocarbon group having 1 to 10 carbon atoms which can be substituted with a hydroxyl group, and among the hydrocarbon groups, one -CH ₂ - or two or more -CH ₂ - which are not adjacent can be replaced by -O-, -S-, -NH-, -NR ₃ -, -C(O)-, -OC(O)-, -OC(O)O-, -SO-, -SO ₂ -, -CONH-, -CONR ₃ -, -OC(O)NH-, or -OC(O)NR ₃ -, wherein R ₃ is a hydrocarbon group having 1 to 10 carbon atoms.

n1, n2, m1, and m2 are each independently integers from 0 to 5, and n1 + m1 and n2 + m2 do not both exceed 5.]

In formula (1), the hydrocarbon groups of R ₁ and R ₂ are concepts including an aliphatic hydrocarbon group and an aromatic hydrocarbon group.

The aliphatic hydrocarbon group of R ₁ and R ₂ is a concept including a linear, branched, or cyclic aliphatic hydrocarbon group, and may be saturated or unsaturated, but saturated is more preferable.

As the linear hydrocarbon group, a linear alkyl group is preferable, and specific examples thereof 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 the like. The linear aliphatic hydrocarbon group preferably has 1 to 8 carbon atoms, and more preferably has 1 to 5 carbon atoms.

As the branched-chain aliphatic hydrocarbon group, a branched-chain alkyl group is preferable, and specific examples thereof include -CH(CH ₃ )CH ₃ , -C(CH ₃ ) ₂ CH ₃ , -CH(CH ₂ CH ₃ )CH ₃ ; alkylpropyl groups such as -CH(CH ₃ )CH ₂ CH ₃ , -CH ₂ CH(CH ₃ )CH ₃ ; alkylbutyl groups such as -CH(CH ₃ )CH ₂ CH ₂ CH ₃ , -CH ₂ CH(CH ₃ )CH ₂ CH ₃ . The above-mentioned branched-chain aliphatic hydrocarbon group preferably has 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms. The above-mentioned cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group, but a monocyclic group is preferred. Examples of the monocyclic group include cyclopentyl and cyclohexyl, and examples of the polycyclic group include isobornyl, norbornyl, tricyclodecanyl, and the like. The above-mentioned cyclic aliphatic hydrocarbon group preferably has 3 to 10 carbon atoms, and more preferably 5 to 10 carbon atoms.

The aromatic hydrocarbon group of R ₁ and R ₂ is a concept including an aralkyl group and an alkylaryl group, and specifically, can include a phenyl group, a phenylethyl group, a phenylpropyl group, a benzyl group, a naphthalene group, etc.

In the case where one -CH ₂ - or two or more -CH ₂ - which are not adjacent, among the hydrocarbon groups of R ₁ and R ₂ are replaced, it is preferable that it is replaced with -O-, -S- or -NH-, and among these, it is particularly preferable that it is replaced with -O-. Specific examples thereof include -OCH ₂ CH ₂ OH, -OCH ₂ CH ₂ CH ₂ OH, -OCH ₂ CH ₂ OCH ₂ CH ₂ OH, -CH ₂ OCH ₂ CH ₂ OH.

The hydrocarbon groups of R ₁ and R ₂ may be substituted or unsubstituted with a hydroxyl group, but particularly when m1 and m2 are each 0, i.e., when the phenyl group does not have a hydroxyl group, it is preferable that the hydrogens of R ₁ and R ₂ be substituted with hydroxyl groups.

The hydrocarbon groups of R ₁ and R ₂ may additionally have a substituent other than a hydroxyl group, and examples of the substituent include a halogen atom or a halogenated alkyl group having 1 to 5 carbon atoms.

R ₁ and R ₂ may be the same or different, but are preferably the same.

In formula (1), n1 and n2 are each independently an integer from 0 to 5, preferably an integer from 0 to 2, more preferably 0 or 1, and particularly preferably 1. n1 and n2 may be the same or different, and are preferably the same.

When n1 and n2 are both integers from 1 to 5, R ₁ and R ₂ may be the same or different, and are preferably the same. In addition, the bonding positions of R ₁ and R ₂ are not particularly limited, but it is preferable that R ₁ and R ₂ exist at the p-position of the phenyl group, and it is preferable that they are bonded at positions that are symmetrical on both sides within the (C) component.

When n1 is 2 or 3, plural R ₁ 's may be the same or different from each other, and when n2 is 2 or 3, plural R ₂ 's may be the same or different from each other.

In formula (1), m1 and m2 are each independently an integer from 0 to 5, more preferably 0 or 1, and particularly preferably 1. m1 and m2 may be the same as or different from each other, and it is more preferable that the sum of m1 and m2 is 0 to 2.
Among these, at least one selected from the group consisting of compounds wherein m1=m2=1, n1=n2=0, compounds wherein m1=m2=0, n1=n2=1, and compounds wherein m1=m2=1, n1=n2=1 is preferable.

In formula (1), the bonding position of each hydroxyl group bonded to the phenyl group is not particularly limited.

(C) Specific examples of the components are listed below.

[Chemical Formula 26]

(C) As for the components, one type may be used alone, or two or more types may be used in combination.

In the resist composition of the present invention, the content of component (C) is preferably 1 to 25 parts by mass, more preferably 2 to 20 parts by mass, even more preferably 2 to 15 parts by mass, particularly preferably 2 to 10 parts by mass, and most preferably 2 to 8 parts by mass, per 100 parts by mass of component (A).

(C) If the content of the component is equal to or higher than the preferred lower limit, pattern dimension changes caused by SW reflection from the substrate or diffuse reflection caused by steps on the substrate surface can be sufficiently reduced. On the other hand, if the content of the component (C) is equal to or lower than the preferred upper limit, the resolution is excellent, which is preferable.

Meanwhile, when the (C) component defined in the present invention is used, compared to when a compound having an anthracene skeleton or a benzophenone skeleton is used, the absorption rate for exposure light is high with a small amount of addition, and not only can the change in pattern dimension due to SW be effectively suppressed while maintaining resolution, but also the toxicity problem can be resolved.

<(D) Component>

The resist composition of the present invention may contain a cross-linking agent as component (D) when component (A) is a polymer having structural units (a1), and (a3), or structural units (a4), and/or (a6), and optionally other structural units (structural unit (a2), etc.). The component (D) is not particularly limited, and may be arbitrarily selected from cross-linking agents currently used in resist compositions.

Specifically, examples thereof include melamine-based cross-linking agents, urea-based cross-linking agents, and glycoluril-based cross-linking agents.

Melamine-based cross-linking agents include compounds in which melamine and formaldehyde are reacted to substitute hydrogen atoms of an amino group with hydroxymethyl groups, and compounds in which melamine, formaldehyde, and alcohol are reacted to substitute hydrogen atoms of an amino group with alkoxymethyl groups. Specific examples thereof include hexamethoxymethylmelamine, hexaethoxymethylmelamine, hexapropoxymethylmelamine, and hexabutoxybutylmelamine, and among these, hexamethoxymethylmelamine is preferable.

Melamine-based cross-linking agents may be used alone or in combination of two or more types.

Examples of urea-based crosslinking agents include compounds in which urea and formaldehyde are reacted to substitute hydrogen atoms of an amino group with hydroxymethyl groups, and compounds in which urea, formaldehyde, and alcohol are reacted to substitute hydrogen atoms of an amino group with alkoxymethyl groups. Specific examples thereof include bismethoxymethyl urea, bisethoxymethyl urea, bispropoxymethyl urea, and bisbutoxymethyl urea, and among these, bismethoxymethyl urea is preferable.

Additionally, as a urea-based crosslinking agent, an alkylene urea-based crosslinking agent can also be preferably used.

As a specific example of an alkylene urea crosslinking agent, a compound represented by the following formula (III) can be mentioned.

[Chemical Formula 27]

[In the formula, R ^1' and R ^2' are each independently a hydroxyl group or an alkoxy group having 1 to 4 carbon atoms, R ^3' and R ^4' are each independently a hydrogen atom, a hydroxyl group or an alkoxy group having 1 to 4 carbon atoms, and v is 0 or an integer of 1 to 2.]

The compound represented by the above formula (III) can be obtained by condensation reaction of alkylene urea and formalin, and by reacting this product with alcohol.

Specific examples of the alkylene urea crosslinking agent include, for example, mono and/or dihydroxymethylated ethylene urea, mono and/or dimethoxymethylated ethylene urea, mono and/or diethoxymethylated ethylene urea, mono and/or dipropoxymethylated ethylene urea, mono and/or dibutoxymethylated ethylene urea, mono and/or dihydroxymethylated propylene urea, mono and/or dimethoxymethylated propylene urea, mono and/or diethoxymethylated propylene urea, mono and/or dipropoxymethylated propylene urea, mono and/or dibutoxymethylated propylene urea, 1,3-di(methoxymethyl)4,5-dihydroxy-2-imidazolidinone, 1,3-di(methoxymethyl)-4,5-dimethoxy-2-imidazolidinone, and the like.

Urea-based cross-linking agents may be used alone or in combination of two or more types.

In addition, as a glycoluril-based crosslinking agent, a glycoluril derivative in which the N position is substituted with one or both of a hydroxyalkyl group and an alkoxyalkyl group having 1 to 4 carbon atoms may be mentioned. Such a glycoluril derivative can be obtained by a condensation reaction of glycoluril and formalin, or by reacting this product with alcohol.

Examples of the glycoluril crosslinking agent include mono, di, tri and/or tetrahydroxymethylated glycoluril, mono, di, tri and/or tetramethoxymethylated glycoluril, mono, di, tri and/or tetraethoxymethylated glycoluril, mono, di, tri and/or tetrapropoxymethylated glycoluril, mono, di, tri and/or tetrabutoxymethylated glycoluril, and the like.

One type of glycoluril crosslinking agent may be used alone, or two or more types may be used in combination.

The content of component (D) in the resist composition of the present invention is preferably 6 to 50 parts by mass, more preferably 10 to 20 parts by mass, per 100 parts by mass of component (A). When the content of component (D) is equal to or greater than the lower limit, crosslinking formation sufficiently progresses, and a good resist pattern is obtained. When it is equal to or less than the upper limit, the storage stability of the resist coating solution is good, and deterioration of sensitivity over time is suppressed.

<Other optional ingredients>

In order to improve the resist pattern shape, stability over time of preservation, etc., the resist composition of the present invention may additionally contain a nitrogen-containing organic compound (E) (hereinafter referred to as component (E)) as an optional component.

This (E) component may be arbitrarily used from known ones, since various ones have already been proposed, but an aliphatic amine, particularly a secondary aliphatic amine or a tertiary aliphatic amine, is preferred.

As the aliphatic amine, there can be mentioned an amine (alkylamine or alkylalcoholamine) in which at least one hydrogen atom of ammonia _NH3 is replaced with an alkyl group or hydroxyalkyl group having 12 or fewer carbon atoms. Specific examples thereof include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, and n-decylamine; dialkylamines such as diethylamine, di-n-propylamine, di-n-heptylamine, di-n-octylamine, and dicyclohexylamine; trialkylamines such as 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, and tri-n-dodecylamine; Examples thereof include alkyl alcohol amines such as diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, and tri-n-octanolamine. Among these, alkyl alcohol amines and trialkyl amines are preferable, and alkyl alcohol amines are most preferable. Among alkyl alcohol amines, triethanolamine and triisopropanolamine are most preferable.

These can be used alone or in combination of two or more.

(E) Component is usually used in the range of 0.01 to 5.0 mass parts per 100 mass parts of (A) component.

In addition, the resist composition of the present invention may contain, as an additional optional component, an organic carboxylic acid, or a phosphorus oxo acid or a derivative thereof (F) (hereinafter referred to as “component (F)”), for the purpose of preventing sensitivity deterioration due to the mixing of the component (E) and improving the resist pattern shape, stability over time after exposure, etc. Furthermore, the component (E) and the component (F) may be used in combination, or either one may be used.

As organic carboxylic acids, malonic acid, citric acid, malic acid, succinic acid, benzoic acid, salicylic acid, etc. are preferable.

Examples of the oxo acids of phosphorus or derivatives thereof include derivatives such as phosphoric acid, phosphoric acid di-n-butyl ester, and phosphoric acid diphenyl ester, and the like, phosphoric acid or their esters; derivatives such as phosphonic acid, phosphonic acid dimethyl ester, phosphonic acid di-n-butyl ester, phenylphosphonic acid, phosphonic acid diphenyl ester, and the like, phosphonic acids and their esters; derivatives such as phosphinic acid, phenylphosphinic acid, and the like, and the like, esters thereof, among these, phosphonic acid is particularly preferable.

(F) Component is used in a ratio of 0.01 to 5.0 parts by mass per 100 parts by mass of (A) Component.

The resist composition of the present invention can be manufactured by dissolving a material in an organic solvent.

As the organic solvent, any solvent that can dissolve each component used and form a uniform solution may be used, and any one or more of those known as solvents for conventional chemically amplified resists may be appropriately selected and used.

For example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, and 2-heptanone; polyhydric alcohols and derivatives thereof such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, or monophenyl ether of ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol, or dipropylene glycol monoacetate; 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, and ethyl ethoxypropionate.

These organic solvents may be used alone or as a mixture of two or more solvents.

Also, a mixed solvent of propylene glycol monomethyl ether acetate (PGMEA) and a polar solvent is preferable. The mixing ratio (mass ratio) may be appropriately determined by considering the compatibility of PGMEA and the polar solvent, etc., and is preferably within the range of 1:9 to 9:1, more preferably within the range of 2:8 to 8:2.

More specifically, when blending EL as a polar solvent, the mass ratio of PGMEA:EL is preferably 1:9 to 9:1, more preferably 2:8 to 8:2. In addition, when blending propylene glycol monomethyl ether (PGME) as a polar solvent, the mass ratio of PGMEA:PGME is preferably 1:9 to 9:1, more preferably 2:8 to 8:2.

In addition, as an organic solvent, a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, the mass ratio of the former and the latter is preferably 70:30 to 95:5 as a mixing ratio.

The amount of the organic solvent to be used is not particularly limited, but is set appropriately according to the thickness of the coating film at a concentration that can be applied to a substrate, etc., and is generally used so that the solid content concentration of the resist composition is within the range of 2 to 20 mass%, preferably 5 to 15 mass%.

The resist composition of the present invention may additionally contain, as desired, additives that are compatible, for example, an additional resin for improving the performance of the resist film, a surfactant for improving the coatability, a dissolution inhibitor, a plasticizer, a stabilizer, a colorant, an anti-halation agent, etc.

As described above, the resist composition of the present invention can form a resist pattern in which pattern dimensional change due to SW is sufficiently suppressed in a thin film having a film thickness that can be used in a thin film implantation process, particularly a thin film having a thickness of 500 nm or less, and therefore the resist composition of the present invention is preferable for a thin film implantation process. Furthermore, the resist composition of the present invention is also excellent in sensitivity and resolution. Since the resist pattern used in the implantation process is used as a mask when implanting impurity ions, the resist composition of the present invention, which not only has small pattern dimensional change due to SW as described above, but also can form a fine pattern with good reproducibility, is preferable for an implantation process.

In addition, the resist composition of the present invention can solve the toxicity problem that occurs when a compound having an anthracene skeleton or a benzophenone skeleton is used as component (C).

In addition, when manufacturing an integrated circuit element having a three-dimensional structure, it is possible to sufficiently reduce incident light from a step substrate during exposure and diffuse reflection from the substrate, and suppress shape defects (SW) of a resist pattern.

< Registry Pattern formation>

In the present invention, a resist pattern can be formed by a process of forming a resist film on a support using the resist composition described above, a process of exposing the resist film, and a process of developing the resist film.

The method for forming a resist pattern of the present invention can be carried out, for example, as follows.

First, the resist composition of the present invention is applied onto a substrate such as a silicon wafer using a spinner, and then a baking treatment (post-apply bake (PAB)) is performed under temperature conditions of 80 to 150°C for 40 to 120 seconds, preferably 60 to 90 seconds, to form a resist film. Next, the resist film is selectively exposed using an exposure device through a desired mask pattern, and then a heating treatment (post-exposure bake (PEB)) is performed under temperature conditions of 80 to 150°C for 40 to 120 seconds, preferably 60 to 90 seconds.

Next, the resist film is developed.

In the case of an alkaline developing process, the developing process is carried out using an alkaline developer, and in the case of a solvent developing process, a developer containing an organic solvent (organic developer) is used.

After the development process, a rinsing process is preferably performed. In the case of an alkaline development process, a water rinse using pure water is preferable, and in the case of a solvent development process, a rinsing solution containing an organic solvent is preferably used.

In the case of a solvent development process, after the development treatment or rinsing treatment, a treatment may be performed to remove the developer or rinsing solution attached to the pattern using a supercritical fluid.

After the developing treatment or the rinsing treatment, drying is performed. In addition, depending on the case, a baking treatment (post-bake) may be performed after the developing treatment. In this way, a resist pattern can be obtained.

The process up to this point can be carried out using a known method. It is desirable to set the operating conditions, etc. appropriately according to the composition or characteristics of the resist composition used.

As an alkaline developer used for developing in an alkaline developing process, an example thereof is a 0.1 to 10 mass% tetramethylammonium hydroxide (TMAH) aqueous solution.

The organic solvent contained in the organic developer used for the development treatment in the solvent development process may be any organic solvent capable of dissolving component (A) (component (A) before exposure), and may be appropriately selected from known organic solvents. Specifically, polar solvents such as ketone solvents, ester solvents, alcohol solvents, amide solvents, and ether solvents, and hydrocarbon solvents can be used.

In the organic developer, known additives can be mixed as needed. Examples of such additives include surfactants. The surfactants are not particularly limited, but examples of surfactants that can be used include ionic or nonionic fluorine-based and/or silicone-based surfactants.

When blending a surfactant, the blending amount is usually 0.001 to 5 mass%, preferably 0.005 to 2 mass%, and more preferably 0.01 to 0.5 mass%, relative to the total amount of the organic developer.

The developing process can be carried out by a known developing method, and examples thereof include a method of immersing a support in a developing solution for a certain period of time (dip method), a method of mounting a developing solution on the surface of a support by surface tension and leaving it there for a certain period of time (paddle method), a method of spraying a developing solution on the surface of a support (spray method), and a method of continuously discharging a developing solution while scanning a developing solution discharging nozzle at a certain speed on a support rotating at a certain speed (dynamic dispensing method).

The rinsing treatment (cleaning treatment) using a rinsing solution can be performed by a known rinsing method. Examples of the method include a method of continuously discharging the rinsing solution onto a support rotating at a constant speed (rotary application method), a method of immersing the support in the rinsing solution for a constant period of time (dip method), and a method of spraying the rinsing solution onto the surface of the support (spray method).

The resist film thickness can be suitably used for a thin film implantation process if it is 500 nm or less, preferably 100 to 450 nm, more preferably 200 to 400 nm.

The radiation used for exposure is not particularly limited, and can be performed using an ArF excimer laser, a KrF excimer laser, an F ₂ laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), electron beam, X-ray, soft X-ray, or the like. The resist composition of the present invention is preferable for use with a KrF excimer laser, an ArF excimer laser, an electron beam, or EUV (extreme ultraviolet), and is particularly preferable for use with a KrF excimer laser.

Additionally, an organic or inorganic anti-reflection film may be formed between the substrate and the resist film, or on the resist film.

The resist pattern obtained in this way is preferable for use in a thin film implantation process because it has little dimensional change even when the thin film is 500 nm or less. In addition, it is preferable because it has little dimensional change when forming a resist pattern on a step substrate.

[ Example ]

Hereinafter, embodiments of the present invention will be described, but the scope of the present invention is not limited to these embodiments.

< Registry Preparation of the composition>

Example 1~3 and Comparative example 1

Negative resist compositions of Examples 1 to 3 and Comparative Example 1 were prepared by mixing and dissolving each component shown in Table 1.

(A) Ingredients (B) Component (C) Ingredients (D) Component (E) Ingredients (F) Ingredients (S) Ingredients Example 1 (A)-1
[100] (B)-1
[2.5] (C)-1
[2.4] (D)-1
[10] (E)-1
[0.38] (F)-1
[0.23] (S)-1
[900] Example 2 (A)-1
[100] (B)-1
[2.5] (C)-1
[4] (D)-1
[10] (E)-1
[0.38] (F)-1
[0.23] (S)-1
[900] Example 3 (A)-1
[100] (B)-1
[2.5] (C)-1
[6] (D)-1
[10] (E)-1
[0.38] (F)-1
[0.23] (S)-1
[900] Comparative Example 1 (A)-1
[100] (B)-1
[2.5] - (D)-1
[10] (E)-1
[0.38] (F)-1
[0.23] (S)-1
[900]

In Table 1, each abbreviation represents the following, and the value in [ ] is the mixing amount (mass part).

(A)-1: Hydroxystyrene (HS)/styrene (ST) copolymer [HS/ST=80/20 (molar ratio), Mw=8,000)]

(B)-1: Triphenylsulfonium camphorsulfonate (TPS-Cs)

(C)-1: A compound represented by the following formula (2)

[Chemical Formula 28]

(2)

(D)-1: Crosslinking agent represented by the following formula (3) (trade name: Nikalac MX-270, manufactured by Sanwa Chemical Co., Ltd.)

[Chemical Formula 29]

(3)

(E)-1: Triethylamine

(F)-1: Salicylic acid

(S)-1: Mixed solvent of PGMEA and PGME (PGMEA:PGME=60:40 (mass ratio))

Example 4~6 and Comparative example 2

Positive resist compositions of Examples 4 to 6 and Comparative Example 2 were prepared by mixing and dissolving each component shown in Table 2.

(A) Ingredients (B) Component (C) Ingredients (E) Ingredients (F) Ingredients (S) Ingredients Example 4 (A)-2
[100] (B)-2
[6.0] (B')-2 [3.0] (C)-1
[4.5] (E)-2
[0.29] (F)-2
[0.09] (S)-2
[700] Example 5 (A)-2
[100] (B)-2
[6.0] (B')-2
[3.0] (C)-1
[6.0] (E)-2
[0.29] (F)-2
[0.09] (S)-2
[700] Comparative Example 6 (A)-2
[100] (B)-2
[6.0] (B')-2
[3.0] (C)-1
[7.5] (E)-2
[0.29] (F)-2
[0.09] (S)-2
[700] Comparative Example 2 (A)-2
[100] (B)-2
[6.0] (B')-2
[3.0] - (E)-2
[0.29] (F)-2
[0.09] (S)-2
[700]

In Table 2, each abbreviation represents the following, and the value in [ ] is the mixing amount (mass parts).

(A)-2: A mixed resin of a copolymer (resin A) represented by the following formula (4) and a copolymer (resin B) represented by the following formula (5) [A/B=65/35 (mass ratio)]

[Chemical formula 30]

(4)

[In the formula, m ¹ :n ¹ = 61:39 (molar ratio), mass average molecular weight = 8,000]

[Chemical Formula 31]

(5)

[In the formula, m ² :n ² = 61:39 (molar ratio), mass average molecular weight = 8,000]

(B)-2: Bis(cyclohexylsulfonyl)diazomethane represented by the following formula (6)

[Chemical formula 32]

(6)

(B')-2: Bis(1,1-dimethylethylsulfonyl)diazomethane represented by the following formula (7)

[Chemical Formula 33]

(7)

(C)-1: Compound represented by formula (2) used in the above examples 1 to 3

(E)-2: Triethanolamine

(F)-2: Maleic acid

(S)-2: Mixed solvent of PGMEA and EL (PGMEA:EL=80:20 (mass ratio))

Example 7~11 and Comparative example 3~6

Positive resist compositions of Examples 7 to 11 and Comparative Examples 3 to 6 were prepared by mixing and dissolving each component shown in Table 3.

(A)
ingredient (B)
ingredient (C)
ingredient (E)
ingredient (F)
ingredient (F')
ingredient (S)
ingredient Example 7 (A)-3
[100] (B)-4
[1.6] (B)-5
[1.41] (B)-6
[0.1] (C)-1
[10] - (F)-1
[0.5] - (S)-3
[3,200] (S)-4
[30] Example 8 (A)-3
[100] (B)-4
[1.6] (B)-5
[1.41] (B)-6
[0.5] (C)-1
[10] - (F)-1
[0.5] - (S)-3
[3,200] (S)-4
[30] Example 9 (A)-3
[100] (B)-4
[1.6] (B)-5
[1.41] (B)-6
[0.5] (C)-1
[15] - (F)-1
[0.5] - (S)-3
[3,200] (S)-4
[30] Example 10 (A)-3
[100] (B)-4
[3.2] - (B)-6
[0.5] (C)-1
[10] - (F)-1
[0.5] - (S)-3
[3,200] (S)-4
[30] Example 11 (A)-3
[100] (B)-4
[2.5] - (B)-6
[0.5] (C)-1
[10] - (F)-1
[0.5] - (S)-3
[3,200] (S)-4
[30] Comparative Example 3 (A)-3
[100] (B)-4
[1.6] (B)-5
[1.41] (B)-6
[0.1] - - (F)-1
[0.5] - (S)-3
[3,200] (S)-4
[30] Comparative Example 4 (A)-3
[100] (B)-4
[3.2] - (B)-6
[0.5] - - (F)-1
[0.5] - (S)-3
[3,200] (S)-4
[30] Example 12 (A)-3
[100] (B)-4
[1.6] (B)-5
[1.41] - (C)-1
[10] (E)-3
[0.28] (F)-1
[0.5] - (S)-3
[3,200] (S)-4
[30] Example 13 (A)-3
[100] (B)-4
[1.6] (B)-5
[1.41] - (C)-1
[10] (E)-3
[0.56] (F)-1
[0.5] - (S)-3
[3,200] (S)-4
[30] Example 14 (A)-4
[100] (B)-4
[1.6] (B)-5
[1.41] - (C)-1
[10] (E)-3
[0.56] (F)-1
[0.5] - (S)-3
[3,200] (S)-4
[30] Example 15 (A)-5
[100] (B)-4
[1.6] (B)-5
[1.41] - (C)-1
[10] (E)-3
[0.56] (F)-1
[0.5] - (S)-3
[3,200] (S)-4
[30] Example 16 (A)-6
[100] (B)-4
[1.6] (B)-5
[1.41] - (C)-1
[10] (E)-3
[0.56] (F)-1
[0.5] - (S)-3
[3,200] (S)-4
[30] Comparative Example 5 (A)-3
[100] (B)-4
[1.6] (B)-5
[1.41] - - (E)-3
[0.28] (F)-1
[0.5] - (S)-3
[3,200] (S)-4
[30] Example 17 (A)-3
[100] (B)-3
[3.04] - (B)-6
[0.1] (C)-1
[2.0] - (F)-1
[0.5] (F')-1
[2.0] (S)-3
[3,200] (S)-4
[30] Example 18 (A)-3
[100] (B)-3
[3.04] - (B)-6
[0.1] (C)-1
[5.0] - (F)-1
[0.5] (F')-1
[2.0] (S)-3
[3,200] (S)-4
[30] Example 19 (A)-3
[100] (B)-3
[3.04] - (B)-6
[0.1] (C)-1
[10] - (F)-1
[0.5] (F')-1
[2.0] (S)-3
[3,200] (S)-4
[30] Comparative Example 6 (A)-3
[100] (B)-3
[3.04] - (B)-6
[0.1] - - (F)-1
[0.5] (F')-1
[2.0] (S)-3
[3,200] (S)-4
[30]

(A)-3 to (A)-6: See Table 4 below:

profit Monomer Composition ratio (molar ratio) Mw Mw/Mn (A)-3 1/2/3/4/8 25/30/20/15/10 9,000 1.75 (A)-4 1/5 50/50 9,000 1.68 (A)-5 1/6/8 45/45/10 7,000 1.59 (A)-6 1/6/7/8 45/40/5/10 7,000 1.65

[Chemical Formula 34]

(B)-3 to (B)-6:

[Chemical Formula 35]

(C)-1: Compound represented by formula (2) used in the above examples 1 to 3

(E)-3: Tripentylamine

(F)-1: Salicylic acid

(F')-1: Fluorinated polymer compound represented by the following formula (7)

[Chemical formula 36]

(7)

[The standard polystyrene-converted weight-average molecular weight (Mw) obtained by GPC measurement is 17,100, and the molecular weight dispersion (Mw/Mn) is 1.71. The copolymer composition ratio (the ratio of each component unit in the structural formula (molar ratio)) obtained by ^13C -NMR is l/m = 52/48]

(S)-3: Mixed solvent of PGMEA and PGME (PGMEA:PGME=70:30 (mass ratio))

(S)-4: γ-butyrolactone

Example 20~27

Negative resist compositions of Examples 20 to 27 were prepared by mixing and dissolving each component shown in Table 5.

(A) Ingredients (B) Component (C) Ingredients (D) Component (E) Ingredients (F) Ingredients (S) Ingredients Example 20 (A)-1
[100] (B)-1
[2.5] (C)-2
[8.26] (D)-1
[10] (E)-3
[0.38] (F)-1
[0.23] (S)-1
[900] Example 21 (A)-1
[100] (B)-1
[2.5] (C)-2
[2.4] (D)-1
[10] (E)-3
[0.38] (F)-1
[0.23] (S)-1
[900] Example 22 (A)-1
[100] (B)-1
[2.5] (C)-2
[4.0] (D)-1
[10] (E)-3
[0.38] (F)-1
[0.23] (S)-1
[900] Example 23 (A)-1
[100] (B)-1
[2.5] (C)-2
[6.25] (D)-1
[10] (E)-3
[0.38] (F)-1
[0.23] (S)-1
[900] Example 24 (A)-1
[100] (B)-1
[2.5] (C)-3
[2.4] (D)-1
[10] (E)-3
[0.38] (F)-1
[0.23] (S)-1
[900] Example 25 (A)-1
[100] (B)-1
[2.5] (C)-3
[4.0] (D)-1
[10] (E)-3
[0.38] (F)-1
[0.23] (S)-1
[900] Example 26 (A)-1
[100] (B)-1
[2.5] (C)-3
[6.25] (D)-1
[10] (E)-3
[0.38] (F)-1
[0.23] (S)-1
[900] Example 27 (A)-1
[100] (B)-1
[2.5] (C)-3
[10.24] (D)-1
[10] (E)-3
[0.38] (F)-1
[0.23] (S)-1
[900]

In Table 5, each abbreviation represents the following, and the value in [ ] is the mixing amount (mass part).

(A)-1, (B)-1, (D)-1, (F)-1 and (S)-1 are defined as below in Table 1.

(C)-2: A compound represented by the following formula (8)

[Chemical Formula 37]

(8)

(C)-3: A compound represented by the following formula (9)

[Chemical formula 38]

(9)

(E)-3: Tripentylamine

Example 28~33

Positive resist compositions of Examples 28 to 33 were prepared by mixing and dissolving each component shown in Table 6.

(A) Ingredients (B) Component (C) Ingredients (E) Ingredients (F) Ingredients (S) Ingredients Example 28 (A)-2
[100] (B)-2
[6.0] (B')-2
[3.0] (C)-2
[4.5] (E)-2
[0.29] (F)-2
[0.09] (S)-2
[700] Example 29 (A)-2
[100] (B)-2
[6.0] (B')-2
[3.0] (C)-2
[6.0] (E)-2
[0.29] (F)-2
[0.09] (S)-2
[700] Example 30 (A)-2
[100] (B)-2
[6.0] (B')-2
[3.0] (C)-2
[7.5] (E)-2
[0.29] (F)-2
[0.09] (S)-2
[700] Example 31 (A)-2
[100] (B)-2
[6.0] (B')-2
[3.0] (C)-3
[4.5] (E)-2
[0.29] (F)-2
[0.09] (S)-2
[700] Example 32 (A)-2
[100] (B)-2
[6.0] (B')-2
[3.0] (C)-3
[6.0] (E)-2
[0.29] (F)-2
[0.09] (S)-2
[700] Example 33 (A)-2
[100] (B)-2
[6.0] (B')-2
[3.0] (C)-3
[7.5] (E)-2
[0.29] (F)-2
[0.09] (S)-2
[700]

In Table 6, each abbreviation represents the following, and the value in [ ] is the mixing amount (mass part).

(A)-2, (B)-2, (B')-2, (E)-2, (F)-2 and (S)-2 are defined as below in Table 2.

(C)-2 and (C)-3 are defined as below in Table 5.

< Registry Evaluation of the composition>

The following evaluations were conducted using the resist composition solutions obtained in Examples 1 to 33 and Comparative Examples 1 to 6.

Example 1~3 and Comparative example 1 of evaluation

[Measuring B-A values]

The negative resist compositions of Examples 1 to 3 and Comparative Example 1 used a TEOS (Tetra ethyl orthosilicate) substrate (topology substrate) on which steps were formed as described above, and SW was calculated as B - A (topographical image).

[Resolution Assessment]

The negative resist composition solutions obtained in Examples 1 to 3 and Comparative Example 1 were uniformly applied onto a TEOS substrate having an 8-inch step using a spinner, and dried by PAB treatment at 100° C. for 60 seconds on a hot plate, thereby forming a resist film having a film thickness of 370 nm.

Next, selective exposure was performed using a KrF exposure device (wavelength 248 nm) NSR-S210 (manufactured by Nikon, NA (numerical aperture) = 0.8, σ = 0.6) through a binary mask.

Then, PEB treatment was performed under the conditions of 110°C for 60 seconds, and paddle development was performed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23°C for 60 seconds, followed by rinsing with purified water for 30 seconds and drying while shaking. In addition, by heating at 100°C for 60 seconds and drying, a 200 nm line-and-space (1:1) resist pattern (hereinafter referred to as L/S pattern) was formed, and observed with a scanning electron microscope (length-measuring SEM, CD4000) manufactured by Hitachi, Ltd., and the exposure dose Exp (sensitivity) (unit: mJ/cm2) that can form a 200 nm L/S pattern was obtained.

The resolution evaluation was given as ○ if a pattern of equal or finer size than the target 200 nm L/S was formed, and the results are shown in Table 7.

[SW Evaluation]

The resist composition solutions obtained in the above Examples 1 to 3 and Comparative Example 1 were used, and the presence or absence of suppression of pattern dimensional change due to SW in the above Exp was observed using a scanning electron microscope.

SW evaluation was performed by observing the cross-sectional shape using a cross-sectional SEM, and if the side surface was almost vertically raised and SW was suppressed, it was given ○, and if the pattern side surface was wavy and SW was not suppressed, it was given ×, and the results are shown in Table 7.

(C) Amount of added ingredients Marine SW inhibition effect B-A (nm) Example 1 Negative type 2.4 ○ ○ 16 Example 2 Negative type 4 ○ ○ 10 Example 3 Negative type 6 ○ ○ 8 Comparative Example 1 Negative type 0 ○ × 65

As is clear from the results shown in Table 7 above, the resist composition of the present invention has excellent effects in terms of resolution and suppression of pattern dimension change due to SW.

From the above results, it was confirmed that by using the composition of the present invention, a fine pattern with suppressed SW can be formed in any case, whether the pattern is formed without using an anti-reflection coating (BARC) or on a step substrate.

Example 4~6 and Comparative example 2 of evaluation

[Resolution Assessment]

The positive resist composition solutions obtained in the above Examples 4 to 6 and Comparative Example 2 were uniformly applied onto a 12-inch bare silicon wafer using a spinner, and dried on a hot plate at 110° C. by PAB treatment, thereby forming a resist film having a film thickness of 280 nm.

Next, selective exposure was performed using a KrF exposure device (wavelength 248 nm) NSR-S210 (manufactured by Nikon, NA (numerical aperture) = 0.8, σ = 0.6) through a binary mask.

Then, PEB treatment was performed under the conditions of 110°C for 60 seconds, and further, paddle development was performed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23°C for 60 seconds, followed by rinsing with purified water for 30 seconds and drying while shaking. Further, by heating at 100°C for 60 seconds and drying, a 200 nm line-and-space (1:1) resist pattern (hereinafter referred to as L/S pattern) was formed, and observed with a scanning electron microscope (length-measuring SEM, CD4000) manufactured by Hitachi, Ltd., and the exposure dose Exp (sensitivity) (unit: mJ/cm2) that can form a 200 nm L/S pattern was obtained.

The criteria for evaluating resolution are the same as those applied in Table 7 above, and the results are shown in Table 8.

[SW Evaluation]

The resist composition solutions obtained in the above Examples 4 to 6 and Comparative Example 2 were used, and the presence or absence of suppression of pattern dimensional change due to SW in the above Exp was observed using a scanning electron microscope.

The SW evaluation criteria are the same as those applied in Table 7 above, and the results are shown in Table 8.

(C) Amount of added ingredients Marine SW inhibition effect B-A (nm) Example 4 Positive type 4.5 ○ ○ - Example 5 Positive type 6 ○ ○ - Example 6 Positive type 7.5 ○ ○ - Comparative Example 2 Positive type 0 ○ × -

As is clear from the results shown in Table 8 above, the resist composition of the present invention has excellent effects in terms of resolution and suppression of pattern dimension change due to SW.

From the above results, it was confirmed that by using the composition of the present invention, a fine pattern with suppressed SW can be formed in any case, whether the pattern is formed without using an anti-reflection coating (BARC) or on a step substrate.

Example 7~11 and Comparative example 3~ 4 of evaluation

[Resolution Assessment]

The positive resist composition solutions obtained in the above Examples 7 to 11 and Comparative Examples 3 to 4 were uniformly applied onto a 12-inch bare silicon wafer using a spinner, and dried by PAB treatment at a temperature of 110° C. for 60 seconds on a hot plate, thereby forming a resist film having a film thickness of 200 nm.

Next, selective exposure was performed using a KrF exposure device (wavelength 248 nm) NSR-S210 (manufactured by Nikon, NA (numerical aperture) = 0.82, σ = 0.83) through a binary mask.

And, in the case of Examples 7 and 8 and Comparative Example 3, PEB treatment was performed at a temperature of 90°C for 60 seconds, and in the case of Examples 9 to 11 and Comparative Example 4, PEB treatment was performed at a temperature of 100°C for 60 seconds, followed by paddle development with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23°C for 30 seconds, followed by rinsing with purified water for 30 seconds and drying while shaking. In addition, by heating at 100°C for 60 seconds and drying, a 200 nm L/S pattern was formed, and the exposure dose Exp (sensitivity) (unit: mJ/cm2) capable of forming a 200 nm L/S pattern was determined by observing with a scanning electron microscope (magnification SEM, CD4000) manufactured by Hitachi, Ltd. The criteria for evaluating resolution are the same as those applied in Table 7 above, and the results are shown in Table 9.

[SW Evaluation]

The resist composition solutions obtained in the above Examples 7 to 11 and Comparative Examples 3 to 4 were used, and the presence or absence of suppression of pattern dimensional change due to SW in the above Exp was observed using a scanning electron microscope. The SW evaluation criteria were the same as the criteria applied in Table 7, and the results are shown in Table 9.

(C) Amount of added ingredients Marine SW inhibition effect Example 7 Positive type 10 ○ ○ Example 8 Positive type 10 ○ ○ Example 9 Positive type 15 ○ ○ Example 10 Positive type 10 ○ ○ Example 11 Positive type 10 ○ ○ Comparative Example 3 Positive type 0 ○ × Comparative Example 4 Positive type 0 ○ ×

As is clear from the results shown in Table 9 above, the resist composition of the present invention has excellent effects in terms of resolution and suppression of pattern dimension change due to SW.

Example 12~16 and Comparative example 5 of evaluation

[Resolution Assessment]

On a 12-inch bare silicon wafer, the positive resist composition solutions obtained in Examples 12 to 16 and Comparative Example 5 were uniformly applied using a spinner, and dried on a hot plate by PAB treatment at a temperature of 90° C. for 60 seconds, thereby forming a resist film having a thickness of 200 nm.

Next, selective exposure was performed using a KrF exposure device (wavelength 248 nm) NSR-S210 (manufactured by Nikon, NA (numerical aperture) = 0.82, σ = 0.83) through a binary mask.

And, for Examples 12 and 13 and Comparative Example 5, PEB treatment was performed at a temperature of 95°C for 60 seconds, and for Examples 14 to 16, PEB treatment was performed at a temperature of 100°C for 60 seconds, followed by paddle development with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23°C for 30 seconds, followed by rinsing with pure water for 30 seconds and drying while shaking. In addition, by heating and drying at 100℃ for 60 seconds, a 200㎚ line and space (1:1) resist pattern was formed (300㎚ pitch/130㎚ line, mask size 130㎚), and observed with a scanning electron microscope (scale SEM, CD4000) manufactured by Hitachi, Ltd., and the exposure dose Exp (sensitivity) (unit: mJ/㎠) that can form a 200㎚ L/S pattern was obtained. The resolution evaluation criteria are the same as the criteria applied in Table 7 above, and the results are shown in Table 10.

[SW Evaluation]

The resist composition solutions obtained in the above Examples 12 to 16 and Comparative Example 5 were used, and the presence or absence of suppression of pattern dimensional change due to SW in the above Exp was observed using a scanning electron microscope. The SW evaluation criteria were the same as the criteria applied in Table 7, and the results are shown in Table 10.

(C) Amount of added ingredients Marine SW inhibition effect Example 12 Positive type 10 ○ ○ Example 13 Positive type 10 ○ ○ Example 14 Positive type 10 ○ ○ Example 15 Positive type 10 ○ ○ Example 16 Positive type 10 ○ ○ Comparative Example 5 Positive type 0 ○ ×

As is clear from the results shown in Table 10, the resist composition of the present invention has excellent effects in terms of resolution and suppression of pattern dimension change due to SW.

Example 17~19 and Comparative example 6 of evaluation

[Resolution Assessment]

On a 12-inch bare silicon wafer, the positive resist composition solutions obtained in Examples 17 to 19 and Comparative Example 6 were uniformly applied using a spinner, and dried by PAB treatment at a temperature of 110° C. for 60 seconds on a hot plate, thereby forming a resist film having a thickness of 200 nm.

Next, selective exposure was performed using a KrF exposure device (wavelength 248 nm) NSR-S210 (manufactured by Nikon, NA (numerical aperture) = 0.82, σ = 0.83) through a binary mask.

And, PEB treatment was performed under the conditions of 90℃ for 60 seconds, and further, paddle development was performed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23℃ for 30 seconds, and then rinsed with purified water for 30 seconds, and dried while shaking. Further, it was heated at 100℃ for 60 seconds and dried to form a 200㎚ line-and-space (1:1) resist pattern (300㎚ pitch/130㎚ line, mask size 130㎚), and observed with a scanning electron microscope (scale SEM, CD4000) manufactured by Hitachi, Ltd., and the exposure amount Exp (sensitivity) (unit: mJ/㎠) that can form a 200㎚ L/S pattern was obtained. The resolution evaluation criteria are the same as the criteria applied in Table 7 above, and the results are shown in Table 11.

[SW Evaluation]

The resist composition solutions obtained in the above Examples 17 to 19 and Comparative Example 6 were used, and the presence or absence of suppression of pattern dimensional change due to SW in the above Exp was observed using a scanning electron microscope. The SW evaluation criteria were the same as the criteria applied in Table 7, and the results are shown in Table 11.

(C) Amount of added ingredients Marine SW inhibition effect Example 17 Positive type 2 ○ ○ Example 18 Positive type 5 ○ ○ Example 19 Positive type 10 ○ ○ Comparative Example 6 Positive type 0 ○ ×

As is clear from the results shown in Table 11 above, the resist composition of the present invention has excellent effects in terms of resolution and suppression of pattern dimension change due to SW.

Example 20~ 33 of evaluation

[Resolution Assessment]

The resist composition solutions obtained in the above Examples 20 to 33 were uniformly applied using a spinner on a 12-inch silicon wafer treated with HMDS (hexamethyldisiloxane), and dried by prebaking on a hot plate at 90° C. for 60 seconds, thereby forming a resist film having a film thickness of 240 nm.

Next, selective exposure was performed using a KrF exposure device (wavelength 248 nm) NSR-S210 (manufactured by Nikon, NA (numerical aperture) = 0.82, σ = 0.83) through a binary mask.

And, PEB treatment was performed at 110℃ for 60 seconds, and further, paddle development was performed at 23℃ for 60 seconds with a 2.38 mass% tetramethylammonium hydroxide aqueous solution, and then, rinsed with purified water for 30 seconds, and dried while shaking. Further, post-baking was performed at 110℃ for 60 seconds and dried to form an L/S pattern (target CD: 140 nm line/425 nm pitch), and observed with a scanning electron microscope (length-measuring SEM, CD4000) manufactured by Hitachi, Ltd., and the exposure amount Exp (sensitivity) (unit: mJ/cm2) capable of forming a 140 nm L/S pattern was obtained. The resolution evaluation criteria are the same as the criteria applied in Table 7 above, and the results are shown in Table 12.

[SW Evaluation]

The resist composition solutions obtained in the above Examples 20 to 33 were used, and the presence or absence of suppression of pattern dimensional change due to SW in the above Exp was observed using a scanning electron microscope. The SW evaluation criteria were the same as the criteria applied in Table 7 above, and the results are shown in Table 12.

(C) Amount of added ingredients Marine SW inhibition effect Example 20 Negative type 8.26 ○ ○ Example 21 Negative type 2.4 ○ ○ Example 22 Negative type 4 ○ ○ Example 23 Negative type 6.25 ○ ○ Example 24 Negative type 2.4 ○ ○ Example 25 Negative type 4 ○ ○ Example 26 Negative type 6.25 ○ ○ Example 27 Negative type 10.24 ○ ○ Example 28 Positive type 4.5 ○ ○ Example 29 Positive type 6 ○ ○ Example 30 Positive type 7.5 ○ ○ Example 31 Positive type 4.5 ○ ○ Example 32 Positive type 6 ○ ○ Example 33 Positive type 7.5 ○ ○

As is clear from the results shown in Table 12 above, the resist composition of the present invention has excellent effects in terms of resolution and suppression of pattern dimension change due to SW.

Claims (11)

A resist composition containing a resin component (A) whose solubility in a developer changes by the action of an acid, an acid generator component (B) which generates acid by exposure, and a compound (C) having a radiation absorption ability represented by the following formula (1):
A resist composition, wherein the resin component (A) contains a structural unit (a1) derived from hydroxystyrene represented by the following formula (a1-1), and further includes a structural unit (a2) in which a hydrogen atom of a hydroxyl group of the structural unit (a1) is substituted with an acid-labile group represented by the following formula (II), and/or a structural unit (a3) represented by the following formula (a3-1).
Equation (1)
[During the meal,
R ₁ and R ₂ are each independently a hydrocarbon group having 1 to 10 carbon atoms which may be substituted with a hydroxyl group, and among the hydrocarbon groups, one -CH ₂ - or two or more -CH ₂ - which are not adjacent may be replaced with -O-, -S- or -NH-.
n1, n2, m1 and m2 are each independently 0 or 1.]

[During the meal,
R is hydrogen, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms that can be substituted with a halogen atom.
^R6 is a hydrocarbon group having 1 to 10 carbon atoms.
p is an integer from 1 to 3.
q is an integer from 0 to 2.]

[In the formula, X and R ¹ are each independently a hydrocarbon group having 1 to 16 carbon atoms, or X and R ¹ are each independently an alkylene group having 1 to 16 carbon atoms, and the terminal of X and the terminal of R ¹ may be combined to form a ring. R ² is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.]

[In the formula, R is a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms that can be substituted with a halogen atom. R ⁷ is a hydrocarbon group having 1 to 10 carbon atoms. r represents an integer from 0 to 3.] A resist composition containing a resin component (A) whose solubility in a developer changes by the action of an acid, an acid generator component (B) which generates acid by exposure, and a compound (C) having a radiation absorption ability represented by the following formula (1):
A resist composition, wherein the resin component (A) contains a polymer compound (A-2) having a structural unit (a4) derived from an acrylic acid ester represented by the following formula (a4-1) or (a4-2) and a structural unit (a5) represented by the following formula (a5-1).
Equation (1)
[During the meal,
R ₁ and R ₂ are each independently a hydrocarbon group having 1 to 10 carbon atoms which may be substituted with a hydroxyl group, and among the hydrocarbon groups, one -CH ₂ - or two or more -CH ₂ - which are not adjacent may be replaced with -O-, -S- or -NH-.
n1, n2, m1 and m2 are each independently 0 or 1.]

[During the meal,
R is hydrogen, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms that can be substituted with a halogen atom.
Va ¹ is a divalent hydrocarbon group having 1 to 30 carbon atoms that may have an ether bond, a urethane bond, or an amide bond.
n _a1 is an integer from 0 to 2.
Ra ¹ is a acid-soluble group.
Ra ² is an acid-labile group represented by the following formula (a4-r-1) or (a4-r-3).
n _a2 is an integer from 1 to 3.
Wa ¹ is a hydrocarbon group having 1 to 30 carbon atoms and valence n _a2 +1.]

[During the meal,
Ra' ¹ , Ra' ² are hydrogen atoms or alkyl groups.
Ra' ³ may be a hydrocarbon group, or may be combined with either Ra' ¹ or Ra' ² to form a ring.
* indicates a combined hand.]

[During the meal,
Ra' ⁷ ~Ra' ⁹ represent alkyl groups.
* indicates a combined hand.]

[During the meal,
R is a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a halogenated hydrocarbon group having 1 to 10 carbon atoms.
Ya ²¹ is a single bond, or a divalent linker.
La ²¹ is -O-, -COO-, -CON(R')-, -OCO-, -CONHCO- or -CONHCS-, and R' represents a hydrogen atom or a methyl group. However, when La ²¹ is -O-, Ya ²¹ cannot be -CO-.
Ra ²¹ is a lactone-containing cyclic group.] In claim 1 or 2,
A resist composition wherein m1 = m2 = 1 in a compound (C) having a radiation absorbing ability represented by formula (1). In claim 1 or 2,
A resist composition, wherein in a compound (C) having a radiation absorbing ability represented by formula (1), R ₁ and R ₂ are each independently a hydrocarbon group having 1 to 5 carbon atoms substituted with a hydroxyl group, and one -CH ₂ - or two or more -CH ₂ - which are not adjacent, among the hydrocarbon groups are replaced with -O-, -S- or -NH-. In claim 1 or 2,
A resist composition wherein the above resin component (A) is a resin whose alkaline solubility increases by the action of an acid. In claim 1 or 2,
A resist composition wherein the resin component (A) is an alkali-soluble resin and further comprises a cross-linking agent component (D). In claim 1 or 2,
A resist composition additionally containing a nitrogen-containing organic compound (E). In claim 1 or 2,
A resist composition for a thin film implantation process. In claim 1 or 2,
A resist composition used to form a resist pattern on a step substrate. A method for forming a resist pattern, characterized by forming a resist film on a substrate using the resist composition described in claim 1 or claim 2, performing a selective exposure process on the resist film, and then performing a development process to form a resist pattern. delete