JP5569402B2 - Radiation sensitive resin composition, polymer and compound - Google Patents

Description

  The present invention relates to a radiation sensitive resin composition, a polymer and a compound.

  Along with miniaturization of various electronic device structures such as semiconductor devices and liquid crystal devices, miniaturization of resist patterns in lithography processes is required. At present, for example, an ArF excimer laser can be used to form a fine resist pattern having a line width of about 90 nm. However, further fine pattern formation is required in the future.

  Conventionally, chemically amplified resist compositions have been widely used for such pattern formation. This chemically amplified resist composition contains an acid generator component that generates an acid upon exposure, and a resin component that changes its solubility in a developer due to the action of this acid (see Patent Document 1), and an exposed portion. It is a composition that can form a pattern by utilizing a difference in dissolution rate from an unexposed portion.

  On the other hand, according to the immersion exposure, it is said that even if a light source having the same exposure wavelength is used, the same high resolution as when a light source having a shorter wavelength is used can be achieved. Therefore, immersion exposure is attracting attention as a technique for achieving high resolution while reducing an increase in cost in the manufacture of semiconductor elements that require a large capital investment. As the resin composition suitable for the immersion exposure, fluorine having high hydrophobicity can be used for the purpose of suppressing the elution of an acid generator and the like from the resist film to the immersion exposure liquid, and improving the drainage of the resist film. A resin composition containing a containing polymer has been proposed (see Patent Document 2).

  However, when the resin composition containing a fluorine-containing polymer having a high hydrophobicity is used, the surface wettability of the developer and the rinsing liquid is reduced, so that the development residue deposited on the resist surface, particularly in the unexposed area, during development. Insufficient removal may cause development defects. Therefore, for the purpose of suppressing the development defects and the like, there has been proposed a resin composition that is hydrophobic during immersion exposure but has a reduced hydrophobicity during alkali development. For example, a resin composition containing a fluorine-containing polymer having an acid-dissociable divalent linking group and an alkali-dissociable group is known (see Patent Document 3). However, this resin composition has the disadvantages of low alkali reactivity and insufficient developer affinity. Further, a resin composition using a polymer having an alkali dissociable group and a fluorocarboxylic acid structure as a water-repellent resin is known (see Patent Document 4). However, even when this resin composition is used, the occurrence of development defects is not sufficiently reduced.

  Furthermore, it is generally known that the resin composition containing a fluorine-containing polymer having high hydrophobicity has a more remarkable deterioration in coverage. Here, the “coverage dependency” means that depending on the mask coverage with respect to the resist film, the radiation sensitivity is high when the mask is low (exposure area is bright), and the radiation is high when it is high (exposure area is dark). It means that sensitivity becomes low. For example, in a conventional resin composition containing a fluorine-containing polymer having high hydrophobicity, the cross-sectional shape of the pattern is likely to be top rounding when the mask coverage is low, and T-top shape when the coverage is high. There is an inconvenience that it is easy to become.

  In addition, the evaluation of the resist film running out of water can be confirmed by using the contact angle with water as an index. However, in actual immersion exposure, in order to shorten the time of the development process, the dynamics during the processing of the developing solution It is also desired that the change in contact angle occur in a shorter time.

JP 59-45439 A International Publication No. 2007 / 116664A JP 2010-020284 A JP 2010-210953 A

  The present invention has been made based on the above circumstances, and its purpose is to have excellent reactivity with an alkaline developer and suppress development defects while ensuring hydrophobicity during immersion exposure. Furthermore, it is to provide a radiation sensitive resin composition having a good coverage dependency, a polymer that can be used in the composition, and a compound that becomes a monomer of the polymer.

（式（１）中、Ｒ^１は、水素原子、フッ素原子、メチル基又はトリフルオロメチル基である。Ｒ^２は、上記式（２）で表される酸解離性基である。
式（２）中、Ｘは、２価の有機基である。ｎは１〜４の整数である。Ｑ^１及びＱ^２は、それぞれ独立して、水素原子、フッ素原子又は１価の有機基である。但し、Ｑ^１及びＱ^２の少なくとも一方は、電子求引性基である。また、ｎが２以上の場合、複数のＱ^１及びＱ^２は、それぞれ同一でも異なっていてもよい。Ｙは、アルカリ解離性基である。） The invention made to solve the above problems is
[A] A radiation-sensitive resin composition containing a polymer having a structural unit (I) represented by the following formula (1) (hereinafter also referred to as “[A] polymer”).

(In Formula (1), R ¹ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ² is an acid dissociable group represented by Formula (2) above.
In formula (2), X is a divalent organic group. n is an integer of 1-4. Q ¹ and Q ² are each independently a hydrogen atom, a fluorine atom, or a monovalent organic group. However, at least one of Q ¹ and Q ² is an electron withdrawing group. When n is 2 or more, the plurality of Q ¹ and Q ² may be the same or different. Y is an alkali dissociable group. )

  [A] polymer which the radiation sensitive resin composition of this invention contains has the structural unit (I) of the said specific structure containing an acid dissociable group and an alkali dissociable group. In particular, due to the above structure having an electron withdrawing group at the α-position of the carboxylic acid, it is easily dissociated by alkali. For example, it is possible to improve the affinity of the developer during alkali development while ensuring hydrophobicity during immersion exposure, and as a result, it is possible to suppress development defects. Furthermore, since the said radiation sensitive resin composition is excellent also in coverage dependency, it can form a favorable fine pattern.

（式（３−１）中、Ｒ^３及びＲ^５は、それぞれ独立して、炭素数１〜４のアルキル基、炭素数４〜２０の１価の脂環式基、又は炭素数６〜２２の１価の芳香族炭化水素基である。Ｒ^４は、炭素数１〜４のアルカンジイル基、炭素数４〜２０の２価の脂環式基、又は炭素数６〜２２の２価の芳香族炭化水素基である。但し、Ｒ^３〜Ｒ^５のいずれか２つが互いに結合して、それらが結合している炭素原子と共に環を形成していてもよい。
式（３−２）中、Ｒ^６及びＲ^８は、それぞれ独立して、水素原子、炭素数１〜４のアルキル基、炭素数４〜２０の１価の脂環式基、又は炭素数６〜２２の１価の芳香族炭化水素基である。Ｒ^７は、単結合、炭素数１〜４のアルカンジイル基、炭素数４〜２０の２価の脂環式基、又は炭素数６〜２２の２価の芳香族炭化水素基である。但し、Ｒ^６〜Ｒ^８のいずれか２つが互いに結合してＲ^６及びＲ^８が結合している炭素原子と共に環を形成していてもよい。
式（３−３）中、Ｒ^９は、炭素数１〜４のアルキル基、炭素数４〜２０の１価の脂環式基、又は炭素数６〜２２の１価の芳香族炭化水素基である。Ｒ^１０は、単結合、炭素数１〜４のアルカンジイル基、炭素数４〜２０の２価の脂環式基、又は炭素数６〜２２の２価の芳香族炭化水素基である。Ｒ^１１は、水素原子、炭素数１〜４のアルキル基、炭素数４〜２０の１価の脂環式基、又は炭素数６〜２２の１価の芳香族炭化水素基である。但し、Ｒ^９〜Ｒ^１１のいずれか２つが互いに結合してＲ^１０及びＲ^１１が結合している炭素原子と共に環を形成していてもよい。
なお、式（３−１）〜（３−３）中、＊は、式（１）中のエステル基との結合部位を示す。また、Ｒ^３〜Ｒ^１１が有する水素原子の一部又は全部は、置換されていてもよい。） X is preferably a divalent group represented by the following formula (3-1), (3-2) or (3-3).

(In Formula (3-1), R ³ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or 6 to 22 carbon atoms. R ⁴ is an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic group having 6 to 22 carbon atoms. It is an aromatic hydrocarbon group, provided that any two of R ^{3 to} R ⁵ may be bonded to each other to form a ring together with the carbon atom to which they are bonded.
In formula (3-2), R ⁶ and R ⁸ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or 6 carbon atoms. It is a monovalent aromatic hydrocarbon group of ˜22. R ⁷ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{6 to} R ⁸ may be bonded to each other to form a ring together with the carbon atom to which R ⁶ and R ⁸ are bonded.
In formula (3-3), R ⁹ is an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms. It is. R ¹⁰ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. R ¹¹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{9 to} R ¹¹ may be bonded to each other to form a ring together with the carbon atom to which R ¹⁰ and R ¹¹ are bonded.
In formulas (3-1) to (3-3), * indicates a binding site with the ester group in formula (1). Moreover, one part or all part of the hydrogen atom which R < ³ > -R < ¹¹ > has may be substituted. )

  When X is a divalent group represented by the above formula (3-1), (3-2) or (3-3), the acid dissociable group of the structural unit (I) in the exposed portion Is easily dissociated by the action of an acid, so that development defects can be further reduced.

As the ^{Q 1} and ^{Q 2,} fluorine atom is preferable. Alkali dissociation is improved by the presence of a fluorine atom having high electron withdrawing property in the vicinity of the ester group bonded to the alkali dissociable group. Thereby, since the developing solution affinity of the resist film formed from the said radiation sensitive resin composition increases, a development defect can be reduced more. Furthermore, the coverage dependency is further improved, and a pattern having a good shape can be formed. In addition, since the polymer [A] has a fluorine atom, the function as a water-repellent resin is improved, which is more suitable for immersion exposure.

  The radiation sensitive resin composition of the present invention further contains a polymer having a [B] acid dissociable group and not having an alkali dissociable group (hereinafter also referred to as “[B] polymer”). Is preferred.

  The radiation-sensitive resin composition contains the [B] polymer, which is a base resin having an acid-dissociable group, so that the acid-dissociable group is dissociated by the action of an acid generated from the acid generator in exposure, It becomes soluble in an alkaline developer. [B] Since the polymer does not have an alkali-dissociable group, the base resin in the unexposed area is hardly soluble in the developer, and the contrast between the exposed area and the unexposed area is improved, resulting in the present invention. This effect can be further increased.

（式（１）中、Ｒ^１は、水素原子、フッ素原子、メチル基又はトリフルオロメチル基である。Ｒ^２は、上記式（２）で表される酸解離性基である。
式（２）中、Ｘは、２価の有機基である。ｎは１〜４の整数である。Ｑ^１及びＱ^２は、それぞれ独立して、水素原子、フッ素原子又は１価の有機基である。但し、Ｑ^１及びＱ^２の少なくとも一方は、電子求引性基である。また、ｎが２以上の場合、複数のＱ^１及びＱ^２は、それぞれ同一でも異なっていてもよい。Ｙは、アルカリ解離性基である。） The present invention also includes a polymer having the structural unit (I) represented by the following formula (1).

(In Formula (1), R ¹ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ² is an acid dissociable group represented by Formula (2) above.
In formula (2), X is a divalent organic group. n is an integer of 1-4. Q ¹ and Q ² are each independently a hydrogen atom, a fluorine atom, or a monovalent organic group. However, at least one of Q ¹ and Q ² is an electron withdrawing group. When n is 2 or more, the plurality of Q ¹ and Q ² may be the same or different. Y is an alkali dissociable group. )

  The polymer of this invention has the structural unit (I) of the said specific structure containing an acid dissociable group and an alkali dissociable group. In particular, due to the above structure having an electron withdrawing group at the α-position of the carboxylic acid, it is easily dissociated by alkali. The radiation-sensitive resin composition containing the polymer, for example, can maintain the hydrophobicity at the time of immersion exposure and can improve the developer affinity at the time of alkali development, thereby further reducing development defects. be able to. Moreover, the coverage dependency is further improved, and a pattern having a good shape can be formed. The said polymer can be used suitably for the said radiation sensitive resin composition, for example.

（式（３−１）中、Ｒ^３及びＲ^５は、それぞれ独立して、炭素数１〜４のアルキル基、炭素数４〜２０の１価の脂環式基、又は炭素数６〜２２の１価の芳香族炭化水素基である。Ｒ^４は、炭素数１〜４のアルカンジイル基、炭素数４〜２０の２価の脂環式基、又は炭素数６〜２２の２価の芳香族炭化水素基である。但し、Ｒ^３〜Ｒ^５のいずれか２つが互いに結合して、それらが結合している炭素原子と共に環を形成していてもよい。
式（３−２）中、Ｒ^６及びＲ^８は、それぞれ独立して、水素原子、炭素数１〜４のアルキル基、炭素数４〜２０の１価の脂環式基、又は炭素数６〜２２の１価の芳香族炭化水素基である。Ｒ^７は、単結合、炭素数１〜４のアルカンジイル基、炭素数４〜２０の２価の脂環式基、又は炭素数６〜２２の２価の芳香族炭化水素基である。但し、Ｒ^６〜Ｒ^８のいずれか２つが互いに結合してＲ^６及びＲ^８が結合している炭素原子と共に環を形成していてもよい。
式（３−３）中、Ｒ^９は、炭素数１〜４のアルキル基、炭素数４〜２０の１価の脂環式基、又は炭素数６〜２２の１価の芳香族炭化水素基である。Ｒ^１０は、単結合、炭素数１〜４のアルカンジイル基、炭素数４〜２０の２価の脂環式基、又は炭素数６〜２２の２価の芳香族炭化水素基である。Ｒ^１１は、水素原子、炭素数１〜４のアルキル基、炭素数４〜２０の１価の脂環式基、又は炭素数６〜２２の１価の芳香族炭化水素基である。但し、Ｒ^９〜Ｒ^１１のいずれか２つが互いに結合してＲ^１０及びＲ^１１が結合している炭素原子と共に環を形成していてもよい。
なお、式（３−１）〜（３−３）中、＊は、式（１）中のエステル基との結合部位を示す。また、Ｒ^３〜Ｒ^１１が有する水素原子の一部又は全部は、置換されていてもよい。） X in the polymer of the present invention is preferably a divalent group represented by the following formula (3-1), (3-2) or (3-3).

(In Formula (3-1), R ³ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or 6 to 22 carbon atoms. R ⁴ is an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic group having 6 to 22 carbon atoms. It is an aromatic hydrocarbon group, provided that any two of R ^{3 to} R ⁵ may be bonded to each other to form a ring together with the carbon atom to which they are bonded.
In formula (3-2), R ⁶ and R ⁸ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or 6 carbon atoms. It is a monovalent aromatic hydrocarbon group of ˜22. R ⁷ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{6 to} R ⁸ may be bonded to each other to form a ring together with the carbon atom to which R ⁶ and R ⁸ are bonded.
In formula (3-3), R ⁹ is an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms. It is. R ¹⁰ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. R ¹¹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{9 to} R ¹¹ may be bonded to each other to form a ring together with the carbon atom to which R ¹⁰ and R ¹¹ are bonded.
In formulas (3-1) to (3-3), * indicates a binding site with the ester group in formula (1). Moreover, one part or all part of the hydrogen atom which R < ³ > -R < ¹¹ > has may be substituted. )

  When the X is a divalent group represented by the formula (3-1), (3-2) or (3-3), the radiation-sensitive resin composition containing the polymer is exposed. In this part, since the acid dissociable group of the structural unit (I) is appropriately dissociated by the action of an acid, the effects of the present invention such as suppression of development defects can be further increased.

（式（４）中、Ｒ^１は、水素原子、フッ素原子、メチル基又はトリフルオロメチル基である。Ｒ^２は、上記式（２）で表される酸解離性基である。
式（２）中、Ｘは、２価の有機基である。ｎは１〜４の整数である。Ｑ^１及びＱ^２は、それぞれ独立して、水素原子、フッ素原子又は１価の有機基である。但し、Ｑ^１及びＱ^２の少なくとも一方は、電子求引性基である。また、ｎが２以上の場合、複数のＱ^１及びＱ^２は、それぞれ同一でも異なっていてもよい。Ｙは、アルカリ解離性基である。） The present invention also includes a compound represented by the following formula (4).

(In Formula (4), R ¹ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ² is an acid dissociable group represented by Formula (2) above.
In formula (2), X is a divalent organic group. n is an integer of 1-4. Q ¹ and Q ² are each independently a hydrogen atom, a fluorine atom, or a monovalent organic group. However, at least one of Q ¹ and Q ² is an electron withdrawing group. When n is 2 or more, the plurality of Q ¹ and Q ² may be the same or different. Y is an alkali dissociable group. )

  The compound of the present invention is suitably used as a monomer compound for synthesizing the polymer.

（式（３−１）中、Ｒ^３及びＲ^５は、それぞれ独立して、炭素数１〜４のアルキル基、炭素数４〜２０の１価の脂環式基、又は炭素数６〜２２の１価の芳香族炭化水素基である。Ｒ^４は、炭素数１〜４のアルカンジイル基、炭素数４〜２０の２価の脂環式基、又は炭素数６〜２２の２価の芳香族炭化水素基である。但し、Ｒ^３〜Ｒ^５のいずれか２つが互いに結合して、それらが結合している炭素原子と共に環を形成していてもよい。
式（３−２）中、Ｒ^６及びＲ^８は、それぞれ独立して、水素原子、炭素数１〜４のアルキル基、炭素数４〜２０の１価の脂環式基、又は炭素数６〜２２の１価の芳香族炭化水素基である。Ｒ^７は、単結合、炭素数１〜４のアルカンジイル基、炭素数４〜２０の２価の脂環式基、又は炭素数６〜２２の２価の芳香族炭化水素基である。但し、Ｒ^６〜Ｒ^８のいずれか２つが互いに結合してＲ^６及びＲ^８が結合している炭素原子と共に環を形成していてもよい。
式（３−３）中、Ｒ^９は、炭素数１〜４のアルキル基、炭素数４〜２０の１価の脂環式基、又は炭素数６〜２２の１価の芳香族炭化水素基である。Ｒ^１０は、単結合、炭素数１〜４のアルカンジイル基、炭素数４〜２０の２価の脂環式基、又は炭素数６〜２２の２価の芳香族炭化水素基である。Ｒ^１１は、水素原子、炭素数１〜４のアルキル基、炭素数４〜２０の１価の脂環式基、又は炭素数６〜２２の１価の芳香族炭化水素基である。但し、Ｒ^９〜Ｒ^１１のいずれか２つが互いに結合してＲ^１０及びＲ^１１が結合している炭素原子と共に環を形成していてもよい。
なお、式（３−１）〜（３−３）中、＊は、式（１）中のエステル基との結合部位を示す。また、Ｒ^３〜Ｒ^１１が有する水素原子の一部又は全部は、置換されていてもよい。） X in the compound of the present invention is preferably a divalent group represented by the following formula (3-1), (3-2) or (3-3).

(In Formula (3-1), R ³ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or 6 to 22 carbon atoms. R ⁴ is an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic group having 6 to 22 carbon atoms. It is an aromatic hydrocarbon group, provided that any two of R ^{3 to} R ⁵ may be bonded to each other to form a ring together with the carbon atom to which they are bonded.
In formula (3-2), R ⁶ and R ⁸ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or 6 carbon atoms. It is a monovalent aromatic hydrocarbon group of ˜22. R ⁷ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{6 to} R ⁸ may be bonded to each other to form a ring together with the carbon atom to which R ⁶ and R ⁸ are bonded.
In formula (3-3), R ⁹ is an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms. It is. R ¹⁰ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. R ¹¹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{9 to} R ¹¹ may be bonded to each other to form a ring together with the carbon atom to which R ¹⁰ and R ¹¹ are bonded.
In formulas (3-1) to (3-3), * indicates a binding site with the ester group in formula (1). Moreover, one part or all part of the hydrogen atom which R < ³ > -R < ¹¹ > has may be substituted. )

  The radiation sensitive containing the polymer synthesize | combined from the compound of this invention as the said X is a bivalent group represented by the said Formula (3-1), (3-2) or (3-3). Since the developing resin composition further reduces development defects and improves the coverage dependency, a pattern having a good shape can be formed.

  Here, the “radiation” of the “radiation sensitive resin composition” is a concept including visible light, ultraviolet rays, far ultraviolet rays, X-rays, charged particle beams and the like.

  According to the radiation sensitive resin composition of the present invention, it is possible to form a resist film having high affinity for a developing solution while ensuring hydrophobicity during immersion exposure. Further, the radiation-sensitive resin composition can improve the coverage dependency and can form a fine pattern with a good shape.

<Radiation sensitive resin composition>
The radiation sensitive resin composition of this invention contains a [A] polymer. Furthermore, it is preferable to contain a [B] polymer, and you may contain an arbitrary component, unless the effect of this invention is impaired. Hereinafter, each component will be described in detail.

<[A] polymer>
[A] The polymer has the structural unit (I) represented by the above formula (1). [A] Since the polymer has the above specific structure, the radiation-sensitive resin composition is excellent in that the acid dissociable group is dissociated in the exposed area to form a polar group and the developer solubility is improved. A shape pattern can be formed. On the other hand, in the unexposed area, while maintaining hydrophobicity in the exposure process, the alkali-dissociable group is dissociated by the alkali developer in the development process to generate a polar group. Moreover, since the structure has an electron withdrawing group at the α-position of the carboxylic acid, the alkali dissociation property is high. Therefore, according to the said radiation sensitive resin composition, the developing solution affinity in the whole resist film improves. As a result, the radiation-sensitive resin composition can suppress development defects, improve the coverage dependency, and form a resist pattern having a good shape.

In formula (1), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ² is an acid dissociable group represented by the above formula (2).
In formula (2), X is a divalent organic group. n is an integer of 1-4. Q ¹ and Q ² are each independently a hydrogen atom, a fluorine atom, or a monovalent organic group. However, at least one of Q ¹ and Q ² is an electron withdrawing group. When n is 2 or more, the plurality of Q ¹ and Q ² may be the same or different. Y is an alkali dissociable group.

  In the above formula (2), the divalent organic group represented by X is not particularly limited as long as it is a group having a structure capable of dissociating from the ester group in the above formula (1) by the action of an acid. A divalent group represented by (3-1), (3-2) or (3-3) is preferable.

In Formula (3-1), R ³ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or 6 to 22 carbon atoms. It is a monovalent aromatic hydrocarbon group. R ⁴ is an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{3 to} R ⁵ may be bonded to each other to form a ring together with the carbon atom to which they are bonded.
In formula (3-2), R ⁶ and R ⁸ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or 6 carbon atoms. It is a monovalent aromatic hydrocarbon group of ˜22. R ⁷ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{6 to} R ⁸ may be bonded to each other to form a ring together with the carbon atom to which R ⁶ and R ⁸ are bonded.
In formula (3-3), R ⁹ is an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms. It is. R ¹⁰ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. R ¹¹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{9 to} R ¹¹ may be bonded to each other to form a ring together with the carbon atom to which R ¹⁰ and R ¹¹ are bonded.
In formulas (3-1) to (3-3), * indicates a binding site with the ester group in formula (1). Moreover, one part or all part of the hydrogen atom which R < ³ > -R < ¹¹ > has may be substituted.

Examples of the alkyl group having 1 to 4 carbon atoms represented by R ³ , R ⁵ , R ⁶ , R ⁸ , R ⁹ and R ¹¹ include, for example, methyl group, ethyl group, n-propyl group, i-propyl group, n -Butyl group, 2-methylpropyl group, 1-methylpropyl group, t-butyl group and the like can be mentioned.

Examples of the monovalent alicyclic group having 4 to 20 carbon atoms represented by the R ³ , R ⁵ , R ⁶ , R ⁸ , R ⁹ and R ¹¹ include, for example,
Monocyclic aliphatic saturated hydrocarbon groups such as cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecyl group, cyclododecyl group;
Monocyclic aliphatic unsaturated hydrocarbon groups such as cyclobutenyl group, cyclopentenyl group, cyclohexenyl group, cyclodecenyl group, cyclododecenyl group, cyclopentadienyl group, cyclohexadienyl group, cyclodecadienyl group;
Bicyclo [2.2.1] heptenyl group, bicyclo [2.2.2] octanyl group, tricyclo [5.2.1.0 ^2,6 ] decanyl group, tricyclo [3.3.1.1 ^3,7 ] Decanyl group, tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] a polycyclic aliphatic saturated hydrocarbon group such as a dodecanyl group or an adamantanyl group;
Bicyclo [2.2.1] heptenyl group, bicyclo [2.2.2] octenyl group, tricyclo [5.2.1.0 ^2,6 ] decenyl group, tricyclo [3.3.1.1. ^3,7 ] decenyl group, tetracyclo [6.2.1.1 ^3,6 . And a polycyclic aliphatic unsaturated hydrocarbon group such as 0 ^2,7 ] dodecenyl group.

Examples of the monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms represented by R ³ , R ⁵ , R ⁶ , R ⁸ , R ⁹ and R ¹¹ include, for example, a benzyl group, a naphthalenyl group, a phenanthrenyl group, and an anthracenyl group. , Tetracenyl group, pentacenyl group, toluenyl group, xylenyl group, ethylbenzyl group, mesityrenyl group, cumenyl group and the like.

Said ^R 4, as the alkanediyl group having 1 to 4 carbon atoms represented by ^{R 7} and ^{R 10,} for example, the ^{R 3, R 5, R 6} , R 8, R 9 and carbon atoms ^{R 11} represents 1 to 4 And a group obtained by removing one hydrogen atom from the alkyl group.

Examples of the divalent alicyclic group having 4 to 20 carbon atoms represented by R ⁴ , R ⁷ and R ¹⁰ include carbon represented by R ³ , R ⁵ , R ⁶ , R ⁸ , R ⁹ and R ^11. Examples thereof include groups in which one hydrogen atom has been removed from the groups listed as the monovalent alicyclic group of formula 4-20.

Examples of the divalent aromatic hydrocarbon group having 6 to 22 carbon atoms represented by R ⁴ , R ⁷ and R ¹⁰ include those represented by R ³ , R ⁵ , R ⁶ , R ⁸ , R ⁹ and R ^11. Examples thereof include groups in which one hydrogen atom has been removed from the groups listed as monovalent aromatic hydrocarbon groups having 6 to 22 carbon atoms.

Examples of the ring that may be formed together with the carbon atoms to which any two of R ^{3 to} R ⁵ are bonded to each other include a cycloalkyl group having 4 to 20 carbon atoms. Specific examples include a polycyclic alicyclic group having a bridged skeleton such as an adamantane skeleton and a norbornane skeleton; a monocyclic alicyclic group having a cycloalkane skeleton such as cyclopentane and cyclohexane. In addition, these groups may be substituted with one or more linear, branched or cyclic alkyl groups having 1 to 10 carbon atoms, for example.

Any two of R ^{6 to} R ⁸ may be bonded to each other to form a carbon atom to which R ⁶ and R ⁸ are bonded, and any two of R ^{9 to} R ¹¹ may be bonded to each other; As the ring that may be formed together with the carbon atom to which R ¹⁰ and R ¹¹ are bonded, for example, any two of the above R ^{3 to} R ⁵ are bonded to each other, and the carbon atom to which each is bonded The ring similar to what was mentioned as a ring which may be formed together can be mentioned. In addition, for example, a C4-C20 heterocyclic ring is mentioned. Specifically, a polycyclic heterocyclic group having a bridged skeleton such as an adamantane skeleton or norbornane skeleton containing an oxygen atom; a monocyclic heterocyclic ring having a cycloalkane skeleton such as cyclopentane or cyclohexane containing an oxygen atom And a formula group. In addition, these groups may be substituted with one or more linear, branched or cyclic alkyl groups having 1 to 10 carbon atoms, for example.

Incidentally, the part or all of ^R 3 ^{to R 11} has a hydrogen atom, which may be ^substituted, R 6, ^{R 8} and ^{R 11} is assumed, except in the case of hydrogen atoms, respectively.

  In said formula (2), as n, 1-3 are preferable and 1 or 2 is more preferable.

In the above formula (2), examples of the monovalent organic group represented by Q ¹ and Q ² include a cyano group, a nitro group, an aryl group having 6 to 20 carbon atoms, and a fluorinated alkyl having 1 to 20 carbon atoms. Group, an acyl group having 2 to 20 carbon atoms, and the like.

Examples of the aryl group having 6 to 20 carbon atoms include benzyl group, naphthalenyl group, phenanthrenyl group, anthracenyl group, tetracenyl group, pentacenyl group, toluenyl group, xylenyl group, ethylbenzyl group, and mesityrenyl group.
Examples of the fluorinated alkyl group having 1 to 20 carbon atoms include a monofluoromethyl group, a difluoromethyl group, a trifluoromethyl group, a 2,2,2-trifluoroethyl group, a pentafluoroethyl group, and a perfluoropropyl group. And a perfluoroisopropyl group.
Examples of the acyl group having 2 to 20 carbon atoms include aliphatic or aromatic groups having 2 to 20 carbon atoms such as acetyl group, propionyl group, butyryl group, isobutyryl group, benzoyl group, 1-naphthoyl group, and 2-naphthoyl group. Group acyl group and the like.

  Among these, a cyano group, a nitro group, a fluorinated alkyl group having 1 to 20 carbon atoms, and an acyl group having 2 to 20 carbon atoms are preferable.

As the ^{Q 1} and ^{Q 2,} an acyl group of a fluorine atom and 2 to 20 carbon atoms are preferable, and fluorine atom is more preferable. In addition, it is more preferable that at least one of Q ¹ and Q ² is an electron withdrawing group, and both are electron withdrawing groups.

  In the above formula (2), the alkali dissociable group represented by Y is not particularly limited as long as the dissociation rate is 1% or less in a pH 6 aqueous solution and 50% or more dissociates in a pH 10 aqueous solution. . Examples thereof include an alkyl group having 1 to 10 carbon atoms, a fluorinated alkyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 20 carbon atoms which may be substituted. Among these, an alkyl group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, and an aryl group having 6 to 10 carbon atoms are preferable. Of these, a methyl group, an ethyl group, and a trifluoroethyl group are more preferable.

  Examples of the structural unit (I) represented by the above formula (1) include structural units represented by the following formulas (1-1) to (1-19).

In the above formula, ^{R 1} has the same meaning as the above formula (1).

  Among these, the structural units represented by (1-9) to (1-16) are preferable.

  [A] In the polymer, the content of the structural unit (I) is preferably 40 mol% or more, more preferably 60 mol% or more, and 70% with respect to all the structural units constituting the [A] polymer. The above is more preferable. [A] The polymer may have one or more structural units (I).

  [A] The polymer has (a1) a structural unit containing an acid dissociable group, (a2) a structural unit containing a polar group, a lactone structure, a sultone structure or a cyclic carbonate structure (a3) a structural unit having a fluorine atom Another structural unit such as (a4) structural unit or (a5) structural unit as a structural unit can be further included. The structural unit can contain one kind or two or more kinds. Hereinafter, each structural unit will be described in detail.

[(A1) Structural unit]
(A1) As a structural unit, the structural unit shown by following formula (5) is mentioned.

In the above formula (5), R ^a1 is a hydrogen atom or a methyl group. R ^{a2 to} R ^a4 are each independently an alkyl group having 1 to 4 carbon atoms or an alicyclic hydrocarbon group having 4 to 20 carbon atoms. However, R ^a3 and R ^a4 may be bonded to each other to form a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms together with the carbon atom to which they are bonded.

  Examples of the alkyl group having 1 to 4 carbon atoms include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, 2-methylpropyl group, 1-methylpropyl group, and t-butyl group. Is mentioned.

The alicyclic hydrocarbon group having 4 to 20 carbon atoms, or the alicyclic hydrocarbon group having 4 to 20 carbon atoms formed together with the carbon atom to which R ^a3 and R ^a4 are bonded to each other. Includes a polycyclic alicyclic group having a bridged skeleton such as an adamantane skeleton or a norbornane skeleton; and a monocyclic alicyclic group having a cycloalkane skeleton such as cyclopentane or cyclohexane. In addition, these groups may be substituted with one or more linear, branched or cyclic alkyl groups having 1 to 10 carbon atoms, for example.

  (A1) As the structural unit, a structural unit represented by the following formula is preferred.

In the above formula, R ^a1 has the same ^{meaning as} the above formula (5). R ^a5 is an alkyl group having 1 to 4 carbon atoms. m is an integer of 1-6.

  Among these, structural units represented by the following formulas (5-1) to (5-20) are more preferable, and (5-4) and (5-12) are particularly preferable.

In the above formula, R ^a1 has the same ^{meaning as} the above formula (5).

  In the [A] polymer, the content ratio of the (a1) structural unit is preferably 5% by mole to 80% by mole, and preferably 10% by mole to 80% by mole with respect to all the structural units constituting the [A] polymer. Is more preferable, and 20 mol% to 70 mol% is particularly preferable. When the content ratio of the structural unit (a1) exceeds 80 mol%, the adhesion of the resist film is lowered, and pattern collapse or pattern peeling may occur. In addition, the [A] polymer may have 1 type or 2 types or more of (a1) structural units.

(A1) Monomers that give structural units include, for example, (meth) acrylic acid-bicyclo [2.2.1] hept-2-yl ester, (meth) acrylic acid-bicyclo [2.2.2] octa. 2-yl ester, (meth) acrylic acid-tricyclo [5.2.1.0 ^2,6 ] dec-7-yl ester, (meth) acrylic acid-tricyclo [3.3.1.1 ^3,7 Deca-1-yl ester, (meth) acrylic acid-tricyclo [3.3.1.1 ^3,7 ] dec-2-yl ester, and the like.

[(A2) Structural unit]
[A] The polymer preferably further includes (a2) a structural unit containing a polar group represented by the following formula. Examples of the “polar group” herein include a hydroxyl group, a carboxyl group, a keto group, a sulfonamide group, an amino group, an amide group, and a cyano group.

  (A2) As a structural unit, the structural unit shown, for example by a following formula is mentioned.

In the above formula, R ^a9 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.

  Among these, the structural unit represented by the above formula (a2-15) is preferable.

  In the [A] polymer, the content ratio of the (a2) structural unit is preferably 5 mol% to 80 mol%, and preferably 8 mol% to 40 mol%, based on all structural units constituting the [A] polymer. Is more preferable. In addition, the [A] polymer may have 1 type (s) or 2 or more types of (a2) structural units.

[(A3) Structural unit]
[A] The polymer may further include (a3) a structural unit having a lactone structure, a sultone structure, or a cyclic carbonate structure. (A3) By having the structural unit, the adhesion of the resist film to the substrate can be improved.

  (A3) As a structural unit, the structural unit shown by a following formula is mentioned, for example.

In the above formula, R ^a6 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^a7 is a hydrogen atom or a methyl group. R ^a8 is a hydrogen atom or a methoxy group. Z ^a1 is a single bond or a methylene group. Z ^a2 is a methylene group or an oxygen atom. a and b are 0 or 1;

  (A3) As the structural unit, a structural unit represented by the following formula is preferred.

In the above formula, R ^a6 is a hydrogen atom or a methyl group.

  [A] In the polymer, the content ratio of the (a3) structural unit is preferably 0 mol% to 70 mol%, and preferably 10 mol% to 40 mol%, based on all structural units constituting the [A] polymer. Is more preferable. By setting it as such a content rate, the adhesiveness of a resist and a board | substrate can be improved. On the other hand, when it exceeds 70 mol%, a good pattern may not be obtained.

  (A3) As a preferable monomer which gives a structural unit, the monomer as described in international publication 2007/116664 pamphlet is mentioned, for example.

[(A4) Structural unit]
(A4) The structural unit is a structural unit represented by the following formula (6).

In the above formula (6), R ^a9 is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ^a10 is a linear or branched alkyl group having 1 to 6 carbon atoms having a fluorine atom, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms having a fluorine atom. However, the alkyl group and the alicyclic hydrocarbon group may be partially or entirely substituted with hydrogen atoms.

  As said C1-C6 linear or branched alkyl group, a methyl group, an ethyl group, a propyl group, a butyl group etc. are mentioned, for example.

  Examples of the monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms include a cyclopentyl group, a cyclopentylpropyl group, a cyclohexyl group, a cyclohexylmethyl group, a cycloheptyl group, a cyclooctyl group, and a cyclooctylmethyl group.

  Of the structural unit (a4) represented by the above formula (6), for example, structural units represented by the following formulas (6-1) and (6-2) are preferable.

In formulas (6-1) and (6-2), R ^a9 has the same ^{meaning as} in formula (6) above.

  (A4) Examples of monomers that give structural units include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, perfluoroethyl (meth) acrylate, perfluoro n-propyl ( (Meth) acrylate, perfluoro i-propyl (meth) acrylate, perfluoro n-butyl (meth) acrylate, perfluoro i-butyl (meth) acrylate, perfluoro t-butyl (meth) acrylate, perfluorocyclohexyl (meth) Acrylate, 2- (1,1,1,3,3,3-hexafluoro) propyl (meth) acrylate, 1- (2,2,3,3,4,4,5,5-octafluoro) pentyl ( (Meth) acrylate, 1- (2,2,3,3,4,4,5,5-octafluoro) hex (Meth) acrylate, perfluorocyclohexylmethyl (meth) acrylate, 1- (2,2,3,3,3-pentafluoro) propyl (meth) acrylate, 1- (2,2,3,3,4, 4,4-Heptafluoro) penta (meth) acrylate, 1- (3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10- Heptadecafluoro) decyl (meth) acrylate, 1- (5-trifluoromethyl-3,3,4,4,5,6,6,6-octafluoro) hexyl (meth) acrylate and the like.

  In the [A] polymer, the content of the (a4) structural unit is preferably 2 mol% to 70 mol%, and preferably 5 mol% to 30 mol% with respect to all the structural units constituting the [A] polymer. More preferred. The [A] polymer may have (a4) one or more structural units.

[(A5) Structural unit]
(A5) The structural unit is a structural unit represented by the following formula (7).

In formula (7), R ^a11 is a hydrogen atom, a methyl group or a trifluoromethyl group. R ^a12 is a (k + 1) ^-valent linking group. ^Xa is ^a divalent linking group having ^a fluorine atom. R ^a13 is a hydrogen atom or a monovalent organic group. k is an integer of 1 to 3. However, when k is 2 or 3, the plurality of X and R ^a13 may be the same or different.

In the above formula (7), examples of the (k + 1) -valent linking group represented by R ^a12 include a linear or branched hydrocarbon group having 1 to 30 carbon atoms and an alicyclic hydrocarbon having 3 to 30 carbon atoms. A group, an aromatic hydrocarbon group having 6 to 30 carbon atoms, or one or more groups selected from the group consisting of these groups and an oxygen atom, a sulfur atom, an ether group, an ester group, a carbonyl group, an imino group, and an amide group And a combination of these. The (k + 1) -valent linking group may have a substituent.

  Examples of the linear or branched hydrocarbon group having 1 to 30 carbon atoms include (k + 1) hydrocarbon groups such as methane, ethane, propane, butane, pentane, hexane, heptane, decane, icosane and triacontane. And a group in which a hydrogen atom is removed.

Examples of the alicyclic hydrocarbon group having 3 to 30 carbon atoms include monocyclic saturated hydrocarbons such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, methylcyclohexane, and ethylcyclohexane;
Monocyclic unsaturated hydrocarbons such as cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclodecene, cyclopentadiene, cyclohexadiene, cyclooctadiene, cyclodecadiene;
Bicyclo [2.2.1] heptane, bicyclo [2.2.2] octane, tricyclo [5.2.1.0 ^2,6 ] decane, tricyclo [3.3.1.1 ^3,7 ] decane, Tetracyclo [6.2.1.1 ^3,6 . 0 ^2,7 ] polycyclic saturated hydrocarbons such as dodecane and adamantane;
Bicyclo [2.2.1] heptene, bicyclo [2.2.2] octene, tricyclo [5.2.1.0 ^2,6 ] decene, tricyclo [3.3.1.1 ^3,7 ] decene, Tetracyclo [6.2.1.1 ^3,6 . And a group obtained by removing (m + 1) hydrogen atoms from a polycyclic hydrocarbon group such as 0 ^2,7 ] dodecene.

  Examples of the aromatic hydrocarbon group having 6 to 30 carbon atoms include an aromatic hydrocarbon group such as benzene, naphthalene, phenanthrene, anthracene, tetracene, pentacene, pyrene, picene, toluene, xylene, ethylbenzene, mesitylene, cumene, and the like (m + 1 ) Groups from which a single hydrogen atom has been removed.

In the above formula (7), the divalent linking group having a fluorine atom represented by X ^a, include a divalent linear hydrocarbon group having 1 to 20 carbon atoms having a fluorine atom. The X ^a, for example, structures represented by Formulas ^{(X a -1) ~ (X} a -6) and the like.

X ^a is preferably a structure represented by the above formulas (X ^a -1) and (X ^a -2).

In the above formula (7), examples of the organic group represented by R ^a13 include, for example, a linear or branched hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 30 carbon atoms, and 6 carbon atoms. To 30 aromatic hydrocarbon groups, or a combination of these groups and one or more groups selected from the group consisting of oxygen, sulfur, ether, ester, carbonyl, imino and amide groups Is mentioned.

  Examples of the structural unit (a5) include structural units represented by the following formulas (7-1) and (7-2).

In the above formula (7-1), R ^a12 is a divalent linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. R ^a11 , X ^a and R ^a13 are as defined in the above formula (7).
In the formula ^{(7-2), R a11, X} a, R a13 and k are as defined in the above formula (7). However, when k is 2 or 3, the plurality of X ^a and R ^a13 may be the same or different.

  Examples of the structural unit represented by the above formula (7-1) and formula (7-2) include the following formula (7-1-1), formula (7-1-2), and formula (7-2-1). The structural unit shown by these is mentioned.

In the formulas (7-1-1), (7-1-2), and (7-2-1), R ^a11 has the same ^{meaning as} the formula (7).

  (A5) Examples of monomers that give structural units include (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-3-propyl) ester and (meth) acrylic acid. (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-butyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy -5-pentyl) ester, (meth) acrylic acid (1,1,1-trifluoro-2-trifluoromethyl-2-hydroxy-4-pentyl) ester, (meth) acrylic acid 2-{[5- ( 1 ′, 1 ′, 1′-trifluoro-2′-trifluoromethyl-2′-hydroxy) propyl] bicyclo [2.2.1] heptyl} ester and the like.

  In the [A] polymer, the content of the (a5) structural unit is preferably 10% by mole to 60% by mole, and preferably 20% by mole to 40% by mole with respect to all the structural units constituting the [A] polymer. More preferred. In addition, the [A] polymer may have 1 type or 2 types or more of (a5) structural units.

  In the [A] polymer, the content of the other structural units is usually 50 mol% or less, preferably 40 mol% or less, preferably 30 mol%, based on all structural units constituting the [A] polymer. The following is more preferable.

  [A] As a compounding quantity of a polymer, 0.1 mass part-20 mass parts are preferable with respect to [B] polymer 100 mass parts mentioned later, 1 mass part-15 mass parts are more preferable, and 2 masses Part to 10 parts by mass is particularly preferable. If it is less than 0.1 part by mass, the effect of containing the [A] polymer may not be sufficient. On the other hand, if the amount exceeds 20 parts by mass, the water repellency of the resist surface becomes too high and development failure may occur.

[A] The polymer preferably contains a fluorine atom. Moreover, it is preferable that the content rate of the fluorine atom in a [A] polymer is larger than a [B] polymer. [A] The content ratio of fluorine atoms in the polymer is usually 5% by mass or more, preferably 5% by mass to 50% by mass, more preferably 5%, based on 100% by mass of the total amount of [A] polymer. It is mass%-45 mass%. In addition, this fluorine atom content rate can be measured by ¹³ C-NMR. [A] A photoresist formed of a radiation-sensitive resin composition containing the [A] polymer and the [B] polymer, when the fluorine atom content in the polymer is larger than that of the [B] polymer. The water repellency of the film surface can be increased, and there is no need to separately form an upper layer film during immersion exposure. Moreover, since the polymer [A] contains the structural unit (I) having an acid dissociable group and an alkali dissociable group, when used as a water-repellent resin in a radiation sensitive resin composition, the hydrophobicity is ensured. However, development defects can be suppressed and a good pattern can be formed. In addition, in order to fully demonstrate the said effect, it is preferable that the difference of the content rate of the fluorine atom in a [B] polymer and the content rate of the fluorine atom in a [A] polymer is 1 mass% or more. More preferably, it is 3 mass% or more.

<[A] Polymer Synthesis Method>
[A] The polymer can be synthesized according to a conventional method such as radical polymerization. For example,
A method in which a solution containing a monomer and a radical initiator is dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction;
A method in which a solution containing a monomer and a solution containing a radical initiator are separately dropped into a reaction solvent or a solution containing a monomer to cause a polymerization reaction;
A plurality of types of solutions containing each monomer and a solution containing a radical initiator are separately added to a reaction solvent or a solution containing a monomer and synthesized by a method such as a polymerization reaction. It is preferable. In addition, when the monomer solution is dropped and reacted with respect to the monomer solution, the monomer amount in the dropped monomer solution is 30 mol with respect to the total amount of monomers used for polymerization. % Or more is preferable, 50 mol% or more is more preferable, and 70 mol% or more is particularly preferable.

  What is necessary is just to determine the reaction temperature in these methods suitably with initiator seed | species. Usually, it is 30 to 180 ° C, preferably 40 to 160 ° C, and more preferably 50 to 140 ° C. The dropping time varies depending on the reaction temperature, the type of initiator, the monomer to be reacted, etc., but is usually 30 minutes to 8 hours, preferably 45 minutes to 6 hours, and more preferably 1 hour to 5 hours. . Further, the total reaction time including the dropping time varies depending on the conditions similarly to the dropping time, but is usually 30 minutes to 8 hours, preferably 45 minutes to 7 hours, and more preferably 1 hour to 6 hours.

  Examples of the radical initiator used in the polymerization include azobisisobutyronitrile (AIBN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), 2,2′-azobis (2 -Cyclopropylpropionitrile), 2,2'-azobis (2,4-dimethylvaleronitrile) and the like. These initiators can be used alone or in admixture of two or more.

Examples of the solvent used for the polymerization include alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 4-methyl-2-pentanol;
Ketones such as acetone, 2-butanone, 4-methyl-2-pentanone, 2-heptanone;
Saturated carboxylic acid esters such as ethyl acetate, n-butyl acetate, i-butyl acetate and methyl propionate;
alkanes such as n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane;
Cycloalkanes such as cyclohexane, cycloheptane, cyclooctane, decalin, norbornane;
Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene;
Halogenated hydrocarbons such as chlorobutanes, bromohexanes, dichloroethanes, hexamethylene dibromide, chlorobenzene;
Ethers such as tetrahydrofuran, dimethoxyethanes, diethoxyethanes;
Etc. These solvents may be used alone or in combination of two or more.

  The resin obtained by the polymerization reaction is preferably recovered by a reprecipitation method. That is, after completion of the polymerization reaction, the target resin is recovered as a powder by introducing the polymerization solution into a reprecipitation solvent. As the reprecipitation solvent, alcohols or alkanes can be used alone or in admixture of two or more. In addition to the reprecipitation method, the resin can be recovered by removing low-molecular components such as monomers and oligomers by a liquid separation operation, a column operation, an ultrafiltration operation, or the like.

  [A] The weight average molecular weight (Mw) in terms of polystyrene by gel permeation chromatography (GPC) of the polymer is not particularly limited, but is preferably 1,000 or more and 500,000 or less, more preferably 2,000 or more and 400,000 or less. Preferably, it is 3,000 or more and 300,000 or less. In addition, when the Mw of the [A] polymer is less than 1,000, the heat resistance when used as a resist tends to decrease. On the other hand, when the Mw of the [A] polymer exceeds 500,000, the developability when used as a resist tends to be lowered.

  [A] The ratio (Mw / Mn) of Mw to the number average molecular weight (Mn) in terms of polystyrene by GPC of the polymer is usually from 1 to 5, preferably from 1 to 3, preferably from 1 to 2. More preferred. By setting Mw / Mn in such a range, the photoresist film has excellent resolution performance.

  Mw and Mn in this specification are GPC columns (Tosoh Corporation, 2 G2000HXL, 1 G3000HXL, 1 G4000HXL), with a flow rate of 1.0 mL / min, elution solvent tetrahydrofuran, and column temperature of 40 ° C. under analysis conditions. The value measured by GPC using monodisperse polystyrene as a standard.

<[B] polymer>
[B] The polymer has an acid dissociable group and does not have an alkali dissociable group. That is, the [B] polymer is an alkali-insoluble or hardly-alkali-soluble resin having an acid-dissociable group, and is a resin that becomes alkali-soluble when the acid-dissociable group is dissociated. Moreover, since it does not have an alkali dissociable group, it is insoluble in an alkali developer in an unexposed area. In the present invention, “alkaline-insoluble or alkali-insoluble” means that the resist film under the alkali development conditions employed when forming a resist pattern from the resist film formed from the radiation-sensitive resin composition. When a film using only the polymer [B] is developed instead of 50%, it means that 50% or more of the initial film thickness of the film remains after development.

  [B] The polymer may have (b1) a structural unit containing an acid dissociable group, (b2) a structural unit having a lactone structure or a cyclic carbonate structure, and (b3) a structural unit containing a polar group as structural units. it can.

  Examples of the structural unit (b1) include the same structural units as those cited as the structural unit (a1) in the [A] polymer. Examples of the structural unit (b2) include the same structural units as those exemplified as the structural unit (a3) in the [A] polymer. In addition, examples of the structural unit (b3) include the same structural units as those exemplified as the structural unit (a2) in the [A] polymer.

  In the [B] polymer, the content ratio of the (b1) structural unit is preferably 5 mol% to 90 mol%, and preferably 10 mol% to 80 mol% with respect to all the structural units constituting the [B] polymer. Is more preferable, and 20 mol% to 70 mol% is particularly preferable. When the content ratio of the structural unit (b1) exceeds 90 mol%, the adhesiveness of the resist film is lowered, and there is a risk of pattern collapse or pattern peeling. In addition, the [B] polymer may have (b1) 1 type, or 2 or more types of structural units.

  [B] In the polymer, the content ratio of the (b2) structural unit is preferably 0 mol% to 70 mol%, and preferably 10 mol% to 60 mol%, based on all structural units constituting the [B] polymer. Is more preferable. By setting it as such a content rate, adhesiveness with a board | substrate can be improved. On the other hand, when it exceeds 70 mol%, the resolution and LWR as a resist may be lowered.

  In the [B] polymer, the content ratio of the (b3) structural unit is preferably 0 mol% to 30 mol%, and preferably 5 mol% to 20 mol%, based on all structural units constituting the [B] polymer. Is more preferable.

<[B] Polymer Synthesis Method>
[B] The polymer can be produced, for example, by polymerizing a monomer corresponding to each predetermined structural unit in a suitable solvent using a radical polymerization initiator.

  Examples of the solvent used for the polymerization include the same solvents as those mentioned in the method for synthesizing the polymer [A].

  As reaction temperature in the said superposition | polymerization, 40 to 150 degreeC and 50 to 120 degreeC are preferable normally. The reaction time is usually preferably 1 hour to 48 hours and 1 hour to 24 hours.

  [B] The Mw of the polymer by the GPC method is preferably 1,000 to 100,000, more preferably 1,000 to 50,000, and particularly preferably 1,000 to 30,000. [B] By making Mw of a polymer into the said range, the said radiation sensitive resin composition containing this is excellent in lithography performance.

  [B] The ratio (Mw / Mn) between Mw and Mn of the polymer is usually 1 to 3, preferably 1 to 2.

<[C] acid generator>
The [C] acid generator generates an acid upon exposure, and the acid dissociates the acid dissociable groups present in the [A] polymer and [B] polymer. As a result, the [A] polymer and the [B] polymer become soluble in the developer. As the inclusion form of the [C] acid generator in the radiation sensitive resin composition, a compound form (hereinafter also referred to as “[C] acid generator”) as described later is incorporated as a part of the polymer. Both forms may be used.

  [C] Examples of the acid generator include onium salt compounds such as sulfonium salts and iodonium salts, organic halogen compounds, and sulfone compounds such as disulfones and diazomethane sulfones. Among these, preferable specific examples of the [C] acid generator include compounds described in paragraphs [0080] to [0113] of JP-A-2009-134088.

  [C] Specific examples of the acid generator include diphenyliodonium trifluoromethanesulfonate, diphenyliodonium nonafluoro-n-butanesulfonate, diphenyliodonium perfluoro-n-octanesulfonate, and bis (4-t-butylphenyl) iodonium. Trifluoromethanesulfonate, bis (4-t-butylphenyl) iodonium nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) iodonium perfluoro-n-octanesulfonate, triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium Nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, cyclohexyl 2-oxocyclohexyl Le methyl trifluoromethanesulfonate, dicyclohexyl-2-oxo-cyclohexyl trifluoromethane sulfonate, 2-oxo-cyclohexyl dimethyl sulfonium trifluoromethane sulfonate, 4-hydroxy-1-naphthyl dimethyl sulfonium trifluoromethane sulfonate,

  4-hydroxy-1-naphthyltetrahydrothiophenium trifluoromethanesulfonate, 4-hydroxy-1-naphthyltetrahydrothiophenium nonafluoro-n-butanesulfonate, 4-hydroxy-1-naphthyltetrahydrothiophenium perfluoro-n- Octanesulfonate, 1- (1-naphthylacetomethyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- (1-naphthylacetomethyl) tetrahydrothiophenium nonafluoro-n-butanesulfonate, 1- (1-naphthylacetomethyl) Tetrahydrothiophenium perfluoro-n-octanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, 1- 3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium nonafluoro -n- butane sulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium perfluoro -n- octane sulfonate,

  Trifluoromethanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, nonafluoro-n-butanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide , Perfluoro-n-octanesulfonylbicyclo [2.2.1] hept-5-ene-2,3-dicarbodiimide, N-hydroxysuccinimide trifluoromethanesulfonate, N-hydroxysuccinimide nonafluoro-n- Butanesulfonate, N-hydroxysuccinimide perfluoro-n-octanesulfonate, and 1,8-naphthalenedicarboxylic acid imide trifluoromethanesulfonate are preferred.

  These [C] acid generators may be used alone or in combination of two or more. [C] The amount of the acid generator used is usually 0.1 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymer [B] from the viewpoint of ensuring sensitivity and developability as a resist. Preferably they are 0.5 mass part or more and 15 mass parts or less. In this case, if the amount of the [C] acid generator used is less than 0.1 parts by mass, the sensitivity and developability tend to decrease. On the other hand, if it exceeds 15 parts by mass, the transparency to radiation decreases, and the desired There is a risk that it may be difficult to obtain a resist pattern.

<[D] Nitrogen-containing compound>
[D] The nitrogen-containing compound controls the diffusion phenomenon of the acid generated from the [C] acid generator upon exposure in the resist film, and suppresses an undesirable chemical reaction in the non-exposed region. While improving further, the storage stability of the obtained radiation sensitive resin composition improves. [D] The inclusion form of the nitrogen-containing compound in the radiation-sensitive resin composition may be a free compound form, a form incorporated as part of a polymer, or both forms.

  [D] The nitrogen-containing compound is represented by the following formula, for example.

In the above formula, R ^{d1 to} R ^d5 are each independently a hydrogen atom, or a linear, branched, or cyclic C 1-20 alkyl group, aryl group, or aralkyl group. However, these groups may have a substituent. In addition, R ^d1 and R ^d2 are bonded to each other with a nitrogen atom to which R ^d1 and R ^d2 are bonded and / or R ^d3 and R ^d4 are bonded to each other with a carbon atom to which R ^d3 and R ^d4 are bonded. Alternatively, an unsaturated hydrocarbon group or a derivative thereof may be formed.

  Examples of the [D] nitrogen-containing compound represented by the above formula include Nt-butoxycarbonyldi-n-octylamine, Nt-amyloxycarbonyldi-n-octylamine, and Nt-butoxycarbonyldi- -N-nonylamine, Nt-amyloxycarbonyldi-n-nonylamine, Nt-butoxycarbonyldi-n-decylamine, Nt-amyloxycarbonyldi-n-decylamine, Nt-butoxycarbonyldicyclohexyl Amine, Nt-amyloxycarbonyldicyclohexylamine, Nt-butoxycarbonyl-1-adamantylamine, Nt-amyloxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl-2-adamantylamine, N -T-amyloxycarbonyl-2-adamantylamine, N- -Butoxycarbonyl-N-methyl-1-adamantylamine, Nt-amyloxycarbonyl-N-methyl-1-adamantylamine, (S)-(-)-1- (t-butoxycarbonyl) -2-pyrrolidine Methanol, (S)-(−)-1- (t-amyloxycarbonyl) -2-pyrrolidinemethanol, (R)-(+)-1- (t-butoxycarbonyl) -2-pyrrolidinemethanol, (R) -(+)-1- (t-amyloxycarbonyl) -2-pyrrolidinemethanol, Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-amyloxycarbonyl-4-hydroxypiperidine, Nt-butoxy Carbonylpyrrolidine, Nt-amyloxycarbonylpyrrolidine, N, N′-di-t-butoxycarbonylpiperazine, N, '-Di-t-amyloxycarbonylpiperazine, N, N-di-t-butoxycarbonyl-1-adamantylamine, N, N-di-t-amyloxycarbonyl-1-adamantylamine, Nt-butoxycarbonyl -4,4'-diaminodiphenylmethane, Nt-amyloxycarbonyl-4,4'-diaminodiphenylmethane, N, N'-di-t-butoxycarbonylhexamethylenediamine, N, N'-di-t-ami Roxycarbonylhexamethylenediamine, N, N, N ′, N′-tetra-t-butoxycarbonylhexamethylenediamine, N, N, N ′, N′-tetra-t-amyloxycarbonylhexamethylenediamine, N, N '-Di-t-butoxycarbonyl-1,7-diaminoheptane, N, N'-di-t-amyloxycarbo Nyl-1,7-diaminoheptane, N, N′-di-t-butoxycarbonyl-1,8-diaminooctane, N, N′-di-t-amyloxycarbonyl-1,8-diaminooctane, N, N′-di-t-butoxycarbonyl-1,9-diaminononane, N, N′-di-t-amyloxycarbonyl-1,9-diaminononane, N, N′-di-t-butoxycarbonyl-1,10 -Diaminodecane, N, N'-di-t-amyloxycarbonyl-1,10-diaminodecane, N, N'-di-t-butoxycarbonyl-1,12-diaminododecane, N, N'-di- t-amyloxycarbonyl-1,12-diaminododecane, N, N′-di-t-butoxycarbonyl-4,4′-diaminodiphenylmethane, N, N′-di-t-amyloxycarbonyl- , 4′-diaminodiphenylmethane, Nt-butoxycarbonylbenzimidazole, Nt-butoxycarbonylbenzimidazole, Nt-amyloxycarbonyl-2-methylbenzimidazole, Nt-butoxycarbonyl-2-phenylbenz Examples thereof include Nt-alkylalkoxycarbonyl group-containing amino compounds such as imidazole and Nt-amyloxycarbonyl-2-phenylbenzimidazole.

  In addition to the nitrogen-containing compound represented by the above formula, examples of the nitrogen-containing compound include a tertiary amine compound, a quaternary ammonium hydroxide compound, a photodegradable base compound, and other nitrogen-containing heterocyclic compounds. It is done.

Examples of tertiary amine compounds include triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri-n-heptylamine, tri-n-octylamine. , Tri (cyclo) alkylamines such as cyclohexyldimethylamine, dicyclohexylmethylamine, and tricyclohexylamine;
Fragrances such as aniline, N-methylaniline, N, N-dimethylaniline, 2-methylaniline, 3-methylaniline, 4-methylaniline, 4-nitroaniline, 2,6-dimethylaniline, 2,6-diisopropylaniline Group amines;
Alkanolamines such as triethanolamine and N, N-di (hydroxyethyl) aniline;
N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetrakis (2-hydroxypropyl) ethylenediamine, 1,3-bis [1- (4-aminophenyl) -1- Methylethyl] benzenetetramethylenediamine, bis (2-dimethylaminoethyl) ether, bis (2-diethylaminoethyl) ether and the like.

  Examples of the quaternary ammonium hydroxide compound include tetra-n-propylammonium hydroxide and tetra-n-butylammonium hydroxide.

  [D] As a content rate of a nitrogen-containing compound, 10 mass parts or less are preferable with respect to 100 mass parts of [B] polymers, and 8 mass parts or less are more preferable. When the amount used exceeds 10 parts by mass, the sensitivity as a resist tends to decrease.

<[E] solvent>
The radiation-sensitive resin composition usually contains an [E] solvent. [E] Examples of the solvent include alcohol solvents, ketone solvents, amide solvents, ether solvents, ester solvents, and mixed solvents thereof.

Examples of alcohol solvents include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, iso-pentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol , Sec-octanol, n-nonyl alcohol, 2,6-dimethyl-4-heptanol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec -Monoalcohol solvents such as heptadecyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol;
Ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2 -Polyhydric alcohol solvents such as ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol;
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl Ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol Monomethyl ether, dipropylene glycol monoethyl ether, polyhydric alcohol partial ether solvents such as dipropylene glycol monopropyl ether.

  Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, methyl-n-pentyl ketone, ethyl-n-butyl ketone, methyl-n- Ketones such as hexyl ketone, di-iso-butyl ketone, trimethylnonanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone, 2,4-pentanedione, acetonyl acetone, diacetone alcohol, acetophenone A solvent is mentioned.

  Examples of the amide solvents include N, N′-dimethylimidazolidinone, N-methylformamide, N, N-dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropionamide, N-methylpyrrolidone and the like can be mentioned.

  Examples of the ester solvents include diethyl carbonate, propylene carbonate, methyl acetate, ethyl acetate, γ-butyrolactone, γ-valerolactone, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec sec -Butyl, n-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methyl pentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, n-nonyl acetate, acetoacetic acid Methyl, ethyl acetoacetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol acetate Cole mono-n-butyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, diacetic acid Glycol, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, iso-amyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate , Diethyl malonate, dimethyl phthalate, diethyl phthalate and the like.

Examples of other solvents include n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane, n-octane, iso-octane, cyclohexane, Aliphatic hydrocarbon solvents such as methylcyclohexane;
Fragrances such as benzene, toluene, xylene, mesitylene, ethylbenzene, trimethylbenzene, methylethylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene, iso-butylbenzene, triethylbenzene, di-iso-propylbenzene and n-amylnaphthalene Group hydrocarbon solvents;
And halogen-containing solvents such as dichloromethane, chloroform, chlorofluorocarbon, chlorobenzene, and dichlorobenzene.

  Of these solvents, propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, ethyl lactate, γ-butyrolactone, and cyclohexanone are preferable.

<Other optional components>
The said radiation sensitive resin composition can contain a [F] uneven distribution promoter, an alicyclic skeleton compound, surfactant, a sensitizer, etc. in the range which does not impair the effect of this invention. Hereinafter, these other optional components will be described in detail. These other optional components can be used alone or in admixture of two or more. Moreover, the compounding quantity of another arbitrary component can be suitably determined according to the objective.

[[F] uneven distribution promoter]
The radiation-sensitive resin composition can be blended with an [F] uneven distribution accelerator when a resist pattern is formed using an immersion exposure method. By blending [F] an uneven distribution accelerator, the [A] polymer can be further unevenly distributed in the vicinity of the surface layer. [F] Examples of the uneven distribution promoter include γ-butyrolactone and propylene carbonate.

[Alicyclic skeleton compound]
An alicyclic skeleton compound is a component that exhibits an action of further improving dry etching resistance, pattern shape, adhesion to a substrate, and the like. Examples of the alicyclic skeleton compound include adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantanecarboxylic acid t-butyl; deoxycholic acid t-butyl, deoxycholic acid t-butoxycarbonylmethyl, Deoxycholic acid esters such as 2-ethoxyethyl deoxycholic acid; Lithocholic acid esters such as tert-butyl lithocholic acid, t-butoxycarbonylmethyl lithocholic acid, 2-ethoxyethyl lithocholic acid; 3- [2-hydroxy-2 , 2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane, 2-hydroxy-9-methoxycarbonyl-5-oxo-4-oxa-tricyclo [4.2.1.0 ^3,7 ] nonane, and the like.

[Surfactant]
Surfactants are components that have the effect of improving coatability, striation, developability, and the like. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, polyoxyethylene n-nonylphenyl ether, polyethylene glycol dilaurate, polyethylene glycol diacrylate. In addition to nonionic surfactants such as stearate, the following trade names are KP341 (Shin-Etsu Chemical Co., Ltd.), Polyflow No. 75, no. 95 (above, Kyoeisha Chemical Co., Ltd.), Ftop EF301, EF303, EF352 (above, Tochem Products), MegaFuck F171, F173 (above, Dainippon Ink and Chemicals), Florard FC430, FC431 ( Sumitomo 3M), Asahi Guard AG710, Surflon S-382, SC-101, SC-102, SC-103, SC-104, SC-105, SC-106 (above, Asahi Glass Co., Ltd.) ) And the like.

[Sensitizer]
The sensitizer absorbs the energy of radiation and transmits the energy to the compound [A], thereby increasing the amount of acid produced. The “sensitivity of the radiation-sensitive resin composition” It has the effect of improving “sensitivity”. Examples of the sensitizer include carbazoles, acetophenones, benzophenones, naphthalenes, phenols, biacetyl, eosin, rose bengal, pyrenes, anthracenes, phenothiazines and the like.

<Preparation of radiation-sensitive composition>
The radiation sensitive resin composition is, for example, the above [A] polymer, the [B] polymer as a suitable component, the [C] acid generator, [D] added as necessary, in the above [E] solvent. It can be prepared by mixing a nitrogen-containing compound and other optional components at a predetermined ratio. The radiation-sensitive resin composition is usually dissolved in an [E] solvent so that the total solid content concentration is 1% by mass to 50% by mass, preferably 2% by mass to 25% by mass, in use. For example, it is prepared by filtering with a filter having a pore size of about 0.2 μm.

<Pattern formation method>
As a pattern formation method using the radiation sensitive resin composition of the present invention, for example,
A step of applying the radiation-sensitive resin composition to a substrate and forming a resist film (hereinafter sometimes referred to as “(i) step”);
A step of exposing the resist film (hereinafter sometimes referred to as “(ii) step”), and a step of alkali developing the exposed resist film (hereinafter also referred to as “(iii) step”).
And the like. Hereinafter, each process is explained in full detail.

[(I) Step]
In this step, the radiation-sensitive resin composition or a composition solution obtained by dissolving this in a solvent is applied to silicon wafer, silicon dioxide, lower layer antireflection by coating means such as spin coating, cast coating, roll coating, etc. A resist film is formed by applying a predetermined film thickness on a substrate such as a wafer covered with a film, and then pre-baking to volatilize the solvent in the coating film. The lower antireflection film can be formed on the substrate surface using, for example, a lower antireflection film forming agent.

[Step (ii)]
In this step, the resist film formed in the step (i) is exposed by irradiation with radiation (in some cases, through an immersion medium such as water). At this time, radiation is irradiated through a mask having a predetermined pattern. As the radiation, irradiation is performed by appropriately selecting from visible light, ultraviolet light, far ultraviolet light, X-rays, charged particle beams and the like according to the line width of the target pattern. Far ultraviolet rays represented by ArF excimer laser (wavelength 193 nm) and KrF excimer laser (wavelength 248 nm) are preferable, and ArF excimer laser is more preferable. Next, the exposed photoresist film is subjected to post-exposure baking (PEB), so that the acid generated from the compound [A] in the exposed portion of the resist film is deprotected. PEB is normally selected and carried out in the range of 50 ° C to 180 ° C.

[(Iii) Step]
In this step, a predetermined photoresist pattern is formed by developing the exposed resist film with a developer. After development, it is common to wash with water and dry. As the developer, for example, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, aqueous ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyl Dimethylamine, triethanolamine, tetramethylammonium hydroxide, pyrrole, piperidine, choline, 1,8-diazabicyclo- [5.4.0] -7-undecene, 1,5-diazabicyclo- [4.3.0] An aqueous alkaline solution in which at least one alkaline compound such as -5-nonene is dissolved is preferable.

  When performing immersion exposure, before the step (ii), in order to protect the direct contact between the immersion liquid and the resist film, an immersion liquid insoluble immersion protective film is formed on the resist film. It may be provided. Examples of the immersion protective film include a solvent peeling type protective film that is peeled off by a solvent before the step (iii) (see, for example, JP-A-2006-227632), and (ii) a developer peeling that peels off simultaneously with the development in the step. Any of the mold protective films (for example, refer to WO2005-069096 and WO2006-035790) may be used. However, from the viewpoint of throughput, it is preferable to use a developer peeling type immersion protective film.

  The resist pattern thus obtained is excellent in pattern shape and suitable for fine processing using lithography technology.

<Polymer>
The polymer of the present invention has the structural unit (I) represented by the above formula (1). Since the polymer has already been described in detail as the [A] polymer contained in the radiation-sensitive resin composition, description thereof is omitted here.

<Compound>
The compound of the present invention is represented by the above formula (4) and is suitably used as a monomer compound for synthesizing the polymer, that is, a monomer compound that gives the structural unit (I).

In formula (4), R ¹ is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group. R ² is an acid dissociable group represented by the above formula (2).
In formula (2), X is a divalent organic group. n is an integer of 1-4. Q ¹ and Q ² are each independently a hydrogen atom, a fluorine atom, or a monovalent organic group. However, at least one of Q ¹ and Q ² is an electron withdrawing group. When n is 2 or more, the plurality of Q ¹ and Q ² may be the same or different. Y is an alkali dissociable group.

  Moreover, as said X, the bivalent group represented by the said Formula (3-1), (3-2) or (3-3) is preferable.

  About the said Formula (4) and (2), since it can be the same description as said Formula (1) and (2) showing the structural unit (I) which a [A] polymer has, the detail here Detailed explanation is omitted.

  Examples of the compound represented by the formula (4) include compounds represented by the following formulas (4-1) to (4-19).

  Among these, the compounds represented by the above formulas (4-9) to (4-16) are preferable.

<Method of compound synthesis>
The compound can be synthesized by the following methods, but is not limited to these methods. As the compound,
(A) A compound in which X in the above formula (2) is an alkanediyl group (the above formula (3-1) or the like), and (b) a compound in which X in the above formula (2) has an acetal structure (the above formula (3) -3) etc.) will be described in detail below.

[(A) Method for synthesizing compound wherein X in formula (2) is alkanediyl group]
(Process 1)
The compound of the present invention is a polymerizable monomer compound represented by the above formula (4). An alcohol having a carboxylic acid ester group (the following formula (c)), which is a precursor of the polymerizable monomer compound, a compound represented by the following formula (a) and a compound represented by the following formula (b) And produced by the method described in known literature (for example, see J. Org. Chem. 1999, 64, 4775-4782), that is, the process shown in the following reaction formula. The method is not limited to this method.

In the above formula (a), R ^{3 ′} and R ^{5 ′} are independently an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or an aromatic carbon atom having 6 to 22 carbon atoms. It is a hydrogen group.
R ^{41 ′} is a single bond or a divalent linking group,
R ^{42 ′ to} R ^{44 ′} are a hydrogen atom or a hydrocarbon group which may have a substituent having 1 to 12 carbon atoms.
However, R ^{3 ′} , R ^{5 ′} and R ^{41 ′ to} R ^{44 ′} may form a ring together with the carbon atoms to which they are bonded.
R ⁰ is a hydrogen atom, methoxymethyl group, tetrahydropyranyl group, t-butyl group, allyl group, benzyl group, trimethylsilyl group, t-butyldimethylsilyl group, acetyl group, pivaloyl group, benzoyl group, etc. It is a protective group for hydroxyl group that is commonly used.
In said formula (b), Z1 ^' is a chlorine atom, a bromine atom, or an iodine atom.
Y ^{1 ′} is a hydrogen atom or an alkali dissociable group.
n ′ is an integer of 1 to 4.
Q ^{1 ′} and Q ^{2 ′} are each independently a hydrogen atom, a fluorine atom or a monovalent organic group, and at least one of them is an electron withdrawing group.

After obtaining the compound (c) in the above step, when R ⁰ is the above protecting group, the next step is performed after performing a general deprotection step.

(Process 2)
Introduction of a polymerizable site and a spacer site to be introduced as necessary can be performed in this step represented by the following reaction formula. The method for introducing the polymerizable site and the spacer site is not limited to this method.

In the above reaction scheme, R ^{3 ′} , R ^{5 ′} , R ^{41 ′ to} R ^{44 ′} , n ′, Q ^{1 ′} , Q ^{2 ′} , and Y ^{1 ′} have the same meaning as the above reaction scheme in Step 1.
R ^{1 ′} is a hydrogen atom, a fluorine atom, a methyl group or a trifluoromethyl group.
Z ^{2 ′} is a hydroxyl group, a halogen atom, —O—CO—C (R ¹ ) ═CH ₂ .

(Process 3)
When the above Y ^{1 ′} that is an alkali-dissociable group is replaced with another alkali-dissociable group Y, this step 3 and step 4 described later can be performed. The compound of the above formula (e) is hydrolyzed in this step to obtain a carboxylic acid (f) in the following reaction formula.

  Examples of the hydrolysis reagent used in the above formula include alkaline aqueous solutions such as an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, an aqueous lithium hydroxide solution, an aqueous cesium hydroxide solution, and an aqueous tetramethylammonium hydroxide solution.

(Process 4)
The compound represented by the above formula (f) is converted into a carboxylic acid halide (g) using a halogenating reagent in this step.

In the above formula (g), Hal ¹ is a halogen atom.
Examples of the halogenating reagent used in the above reaction include thionyl chloride, oxalyl chloride and the like.

(Process 5)
Carboxylic acid ester (h) is compoundable by making the compound represented by the said Formula (g) react with alcohols or phenols at this process.

  In the above reaction formula, Y ′ is an optionally substituted aliphatic hydrocarbon group having 2 to 10 carbon atoms or an optionally substituted aromatic hydrocarbon group. However, a part or all of the hydrogen atoms of the substituent that the aliphatic hydrocarbon group may have are substituted with fluorine atoms.

  The conversion reaction from (g) to (h) in the above reaction formula can also be performed using a corresponding esterifying agent. Examples of the esterifying agent include N, N′-dicyclohexylcarbodiimide, 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride, and the like.

[(B) Method for synthesizing compound in which X in formula (2) contains acetal structure]
(Process 1)
Alcohols having a carboxylic acid ester group (formula (i) below), which is a precursor of the compound of the present invention, can be obtained from known literature (for example, J. Chem. Soc., Chemical Communications, 1992, 7, p. 540-541, J. Chem. Soc., Perkin Transactions 1: Similar to Organic and Bio-or, "Chemistry (1992-1999), 1993, 10p. 1177-1182), that is, a process represented by the following reaction formula However, it is not limited to this method.

The introduction of the polymerizable moiety can be introduced by directly linking units having a polymerizable moiety in the same step with reference to the above (Step 2), but is not limited to this method.
Moreover, the compound which converted Y < ¹ >'' into Y 'can be manufactured in the same process with reference to the said (process 3)-(process 5), However, It is not limited to this method.
In addition, the compound of this invention is compoundable suitably by the method according to the said synthesis method and this.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Mw and Mn of the polymer were measured under the following conditions using GPC columns (Tosoh Corporation, 2 G2000HXL, 1 G3000HXL, 1 G4000HXL).
Column temperature: 40 ° C
Elution solvent: Tetrahydrofuran (Wako Pure Chemical Industries)
Flow rate: 1.0 mL / min Sample concentration: 1.0 mass%
Sample injection volume: 100 μL
Detector: Differential refractometer Standard material: Monodisperse polystyrene

¹ H-NMR analysis and ¹³ C-NMR analysis were measured using a nuclear magnetic resonance apparatus (JEOL Ltd., JNM-ECX400P).

<Synthesis of compounds>
[Example 1] Synthesis of 2,2-difluoro-5- (methacryloyloxy) -5-methyl-hexanoic acid ethyl ester (M-1)

Synthesis of 2,2-difluoro-5-hydroxy-5-methyl-hexanoic acid ethyl ester In a 1000 mL three-necked flask, 31.8 g (0.2 mol) of ethyl chlorodifluoroacetate was added 2-methyl-3-butene. -2-ol 25.8 g (0.3 mol), hydrosulfite sodium 52.2 g (0.3 mol), sodium bicarbonate 25.2 g (0.3 mol), dimethyl sulfoxide 1000 mL, After stirring and suspending, the mixture was heated to 75 ° C. in an oil bath and stirred for 6 hours. After confirming the completion of the reaction by gas chromatography, the reaction solution was cooled to room temperature, and the reaction solution was added to 1000 mL of 0 degree ultrapure water so that the temperature did not rise. Thereafter, 500 mL of tetrahydrofuran was added to the mixed solution, and the organic layer was recovered by a liquid separation operation. Furthermore, 500 mL of tetrahydrofuran was added to the aqueous layer to perform a liquid separation operation, and the operation of recovering the organic layer was repeated a total of 5 times. All the recovered organic layers were combined and concentrated under reduced pressure using an evaporator. To the concentrate, 1000 mL of ethyl acetate was added, and 1000 mL of ultrapure water was further added as a cleaning solution for liquid separation, and the aqueous layer was discarded. 1000 mL of ultrapure water was added to the organic layer for liquid separation, and the operation of discarding the aqueous layer was performed three times. The organic layer washed with ultrapure water was concentrated under reduced pressure with an evaporator, and purified by silica gel column chromatography (developing solvent: n-hexane / ethyl acetate = 4/1) to obtain the following formula (m-1). 12.6 g of 2,2-difluoro-5-hydroxy-5-methyl-hexanoic acid ethyl ester represented was obtained (yield 30%, purity 99%).
The ¹ H-NMR data of 2,2-difluoro-5-hydroxy-5-methyl-hexanoic acid ethyl ester is shown below.
¹ H-NMR (measurement solvent: CDCl ₃ , reference material: tetramethylsilane): σ = 4.34 (q 2H, O—CH ₂ CH ₃ CH ₂ ), 2.19 (m, 2H, —CF ₂ CH ₂ —CH ₂ ), 1.63 (m, 2H, C—CH ₂ CH ₂ ), 1.37 (t, 3 H, O—CH ₂ CH ₃ CH ₃ ), 1.25 (t , 6H, _CH 3 of C (CH _3)).

In a 100 mL three-necked flask, 40 g of dichloromethane, 4.20 g (0.02 mol) of 2,2-difluoro-5-hydroxy-5-methyl-hexanoic acid ethyl ester (m-1), 1,4- 2.69 g (0.024 mol) of diazabicyclo [2.2.2] octane (DABCO) was added, the inside of the reactor was purged with nitrogen, and then cooled to 0 ° C. Thereto, 2.67 g (0.021 mol) of methacrylic acid chloride dissolved in 20 g of dichloromethane was slowly added dropwise so that the reaction solution temperature did not rise. After the completion of the dropwise addition, the mixture was stirred for 30 minutes while maintaining 0 degree. After confirming the completion of the reaction by gas chromatography, the reaction solution was cooled to 0 degree, and 100 ml of n-hexane cooled to 0 degree and 20 g of silica gel were added to terminate the reaction. The reaction solution was passed through a short column (silica gel 50 g, developing solvent: n-hexane) with n-hexane to give 2,2-difluoro-5- (methacryloyloxy) represented by the following formula (M-1). ) -5.15-methyl-hexanoic acid ethyl ester was obtained (yield 93%, purity 99%).
The ¹ H-NMR data of 2,2-difluoro-5- (methacryloyloxy) -5-methyl-hexanoic acid ethyl ester is shown below.
¹ H-NMR (measurement solvent: CDCl ₃ , reference material: tetramethylsilane): σ = 6.00 (s, 1H, ═CH ₂ ), 5.50 (s, 1H, ═CH ₂ ), 4.35 (q, 2H, _CH 2 of _{O-CH 2 CH 3),} 2.18 (m, 2H, -CF 2 CH 2 - of _{CH 2), 1.92 (m,} 2H, a C-CH ₂ CH _{2 ), 1.90 (s, 3H,} CH 3 -C), 1.51 (t, 6H, C (CH 3) CH 3 in), 1.36 (t, 3H, CH of _O-CH 2 _{CH 3 3} ).

[Example 2] Synthesis of 2,2,2-trifluoroethyl 2,2-difluoro-5- (methacryloyloxy) -5-methyl-hexanoate (M-2)

Synthesis of intermediate compound 2,2-difluoro-5- (methacryloyloxy) -5-methyl-hexanoic acid (m-2) 300 mL of a 2.38 wt% tetramethylammonium hydroxide aqueous solution was placed in a 500 mL three-necked flask. It was. 5 g of 2,2-difluoro-5- (methacryloyloxy) -5-methyl-hexanoic acid ethyl ester obtained in Example 1 was added at room temperature and stirred for 2 hours. After confirming complete dissolution and confirming that the raw material had disappeared by gas chromatography, dilute hydrochloric acid was added to adjust the pH of the aqueous layer to 5. 100 mL of ethyl acetate was added, the organic layer was recovered by a liquid separation operation, and the aqueous layer was further extracted three times with 100 mL of ethyl acetate. All the obtained organic layers were combined, 0.01 g of 4-methoxyphenol was added, and the mixture was concentrated under reduced pressure. The resulting concentrated liquid was purified by silica gel chromatography (developing solvent: n-hexane / ethyl acetate = 1/1, acetic acid added as 2 w% as a buffer), and represented by the following formula (m-2) 2,2 2.1 g of difluoro-5- (methacryloyloxy) -5-methyl-hexanoic acid was obtained (yield 47%, purity 90%).
¹ H-NMR data of 2,2-difluoro-5- (methacryloyloxy) -5-methyl-hexanoic acid are shown below.
¹ H-NMR (measurement solvent: CDCl ₃ , reference material: tetramethylsilane): σ = 6.01 (s, 1H, ═CH ₂ ), 5.50 (s, 1H, ═CH ₂ ), 2.17 (M, 2H, —CF ₂ CH ₂ — CH ₂ ), 1.92 (m, 2H, C—CH ₂ CH ₂ ), 1.90 (s, 3H, CH ₃ —C), 1.51 (t, 6H, _CH 3 of C (CH _3)).

200 mL of dichloromethane, 2.79 g (0.022 mol) of oxalyl chloride and 1 drop of N, N-dimethylformamide were added to a 300 mL three-necked flask, and the temperature of the reaction solution was adjusted to 0 ° C. with ice cooling. 5.00 g (0.02 mol) of the compound (m-2) was dissolved in 100 mL of dichloromethane, and this was slowly added dropwise to the reaction solution so that the temperature did not rise. After completion of the dropping, the mixture was stirred at 0 degree for 30 minutes, and further stirred at room temperature for 4 hours. After confirming the disappearance of the raw materials by gas chromatography, the reaction solution was cooled to 0 ° C., and 2.22 g (0.022 mol) of triethylamine was slowly added dropwise so that the temperature of the reaction solution did not rise. After completion of the dropwise addition, the mixture was stirred for 10 minutes, and 2.40 g (0.024 mol) of 2,2,2-trifluoroethanol was added. After stirring at room temperature for 2 hours, the progress of the reaction was confirmed by gas chromatography, and the reaction solution was concentrated under reduced pressure using an evaporator. 50 g of n-hexane is added to the concentrate, and the mixture is passed through a short column (silica gel 50 g, developing solvent: n-hexane) with n-hexane, and represented by the following formula (M-2) 2,2 , 2-trifluoroethyl 2,2-difluoro-5- (methacryloyloxy) -5-methyl-hexanoate was obtained (yield 90%, purity 98%).
¹ H-NMR data of 2,2,2-trifluoroethyl 2,2-difluoro-5- (methacryloyloxy) -5-methyl-hexanoate is shown below.
¹ H-NMR (measurement solvent: CDCl ₃ , reference material: tetramethylsilane): σ = 6.02 (s, 1H, ═CH ₂ ), 5.52 (s, 1H, ═CH ₂ ), 4.61 (q, 2H, _CH 2 of _{O-CH 2 CF 3),} 2.19 (m, 2H, -CF 2 CH 2 - of _{CH 2), 1.92 (m,} 2H, a C-CH ₂ CH _{2 ), 1.90 (s, 3H,} CH 3 -C), 1.51 (t, 6H, C (CH 3) CH 3 in), 1.36 (t, 3H, CH of _O-CH 2 _{CH 3 3} ).

[Example 3] Synthesis of 3-trifluoromethylphenyl 2,2-difluoro-5- (methacryloyloxy) -5-methyl-hexanoate (M-3) In place of 2,2,2-trifluoroethanol, 3- 3-trifluoromethylphenyl 2,2-difluoro-5- (methacryloyloxy) -5-methyl represented by the following formula (M-3) in the same manner as in Example 2 except that hydroxybenzotrifluoride was used. -Hexanoate was obtained (yield 88%, purity 99%).
¹ H-NMR data of 3-trifluoromethylphenyl 2,2-difluoro-5- (methacryloyloxy) -5-methyl-hexanoate are shown below.
¹ H-NMR (measurement solvent: CDCl ₃ , reference material: tetramethylsilane): σ = 7.56 ( _4th and 6th positions of m, 2H, O—C ₆ H ₄ —CF ₃ ), 7.40 (s , 1H, 2nd position of O—C ₆ H ₄ —CF ₃ ), 7.34 (5th position of m, 1H, O—C ₆ H ₄ —CF ₃ ), 6.00 (s, 1H, ═CH _{2 ), 5.50 (s, 1H,} = CH 2), 2.20 (m, 2H, -CF 2 CH 2 - of _{CH 2), 1.93 (m,} 2H, CH 2 of C-CH _{2) , 1.89 (s, 3H, CH} 3 -C), 1.51 (t, 6H, CH 3 of C (CH _3)).

[Example 4] Synthesis of 1-ethoxy-2,2-difluoro-3-ethoxy-3-oxopropyl methacrylate (M-4) 2,2-difluoro-5-hydroxy-5-methyl-hexanoic acid ethyl ester Instead, 1-ethoxy-2,2-represented by the following formula (M-4) in the same manner as in Example 1 except that ethyl 3-ethoxy-2,2-difluoro-3-hydroxypropionate was used. Difluoro-3-ethoxy-3-oxopropyl methacrylate was obtained (yield 95%, purity 99%).
The ¹ H-NMR data of ¹ -ethoxy-2,2-difluoro-3-ethoxy-3-oxopropyl methacrylate are shown below.
¹ H-NMR (measurement solvent: CDCl ₃ , reference material: tetramethylsilane): σ = 6.27 (s, 1H, ═CH ₂ ), 6.21 (dd, 1H, CH of O—CH—O) _{, 5.72 (s, 1H, =} CH 2), 4.36 (q, 2H, CH 2 of _{O-CH 2 CH 3),} 3.94-3.73 (m, 2H, CH-O-CH ₂ CH ₃ CH ₂ ), 1.97 (s, 3 H, CH ₃ —C), 1.36 (t, 3 H, O—CH ₂ CH ₃ CH ₃ ), 1.24 (t, 3 H, CH _CH 3 of _-O-CH 2 _{CH 3).}

Example 5 Synthesis of 2,2-difluoro-5- (methacryloyloxy) -5-methyl-hexanoic acid methyl ester (M-5) 2,2-synthesized in Example 1 in a 500 mL three-necked flask Difluoro-5- (methacryloyloxy) -5-methyl-hexanoic acid ethyl ester (10 g), methanol (300 mL), dimethylaminopyridine (DMAP) (0.1 g) and 4-methoxyphenol (0.1 g) were added under nitrogen atmosphere. At reflux for 14 hours. After confirming that the conversion was 95% or more by gas chromatography, the reaction solution was concentrated under reduced pressure using an evaporator. The concentrated solution is dissolved in 30 g of n-hexane, and the solution is passed through a short column (silica gel 30 g, developing solvent = n-hexane), whereby 2,2-difluoro- represented by the following formula (M-5) is obtained. 8.1 g of 5- (methacryloyloxy) -5-methyl-hexanoic acid methyl ester was obtained (yield 85%, purity 97%).
The ¹ H-NMR of 2,2-difluoro-5- (methacryloyloxy) -5-methyl-hexanoic acid methyl ester is shown below.
¹ H-NMR (measurement solvent: CDCl ₃ , reference material: tetramethylsilane): σ = 6.00 (s, 1H, ═CH ₂ ), 5.50 (s, 1H, ═CH ₂ ), 3.86 _{(s, 3H, O-CH} 3), 2.18 (m, 2H, -CF 2 CH 2 - of _{CH 2), 1.92 (m,} 2H, CH 2 of C-CH _2), 1.90 _{(s, 3H, CH 3 -C} ), 1.51 (t, 6H, CH 3 of C (CH _3)).

Example 6 Synthesis of 2,2-difluoro-4- (1-methacryloyloxycyclohexyl) -butanoic acid ethyl ester (M-6) In a 1000 mL three-necked flask, 31.8 g (0 .2 mol), 37.9 g (0.3 mol) of 1-vinylcyclohexanol, 52.2 g (0.3 mol) of hydrosulfite sodium, 25.2 g (0.3 mol) of sodium bicarbonate, After adding 1000 mL of dimethyl sulfoxide and stirring and suspending, it heated to 75 degree | times with the oil bath and stirred for 7 hours. After confirming the completion of the reaction by gas chromatography, the reaction solution was cooled to room temperature, and the reaction solution was added to 1000 mL of 0 degree ultrapure water so that the temperature did not rise. Thereafter, 500 mL of tetrahydrofuran was added to the mixed solution, and the organic layer was recovered by a liquid separation operation. Furthermore, 500 mL of tetrahydrofuran was added to the aqueous layer to perform a liquid separation operation, and the operation of recovering the organic layer was repeated a total of 5 times. All the recovered organic layers were combined and concentrated under reduced pressure using an evaporator. To the concentrate, 1000 mL of ethyl acetate was added, and 1000 mL of ultrapure water was further added as a cleaning solution for liquid separation, and the aqueous layer was discarded. 1000 mL of ultrapure water was added to the organic layer for liquid separation, and the washing operation for discarding the aqueous layer was performed 3 times in total. The organic layer washed with ultrapure water was concentrated under reduced pressure using an evaporator, and purified by silica gel column chromatography (developing solvent: n-hexane / ethyl acetate = 4/1) to obtain the following formula (m-6). 15.9 g of the represented 2,2-difluoro-4- (1-hydroxycyclohexyl) -butanoic acid ethyl ester was obtained (yield 22.4%, purity 99%).
¹ H-NMR data of the physical properties of the above 2,2-difluoro-4- (1-hydroxycyclohexyl) -butanoic acid ethyl ester are shown below.
¹ H-NMR (measurement solvent: CDCl ₃ , reference material: tetramethylsilane): σ = 4.34 (q 2H, O—CH ₂ CH ₃ CH ₂ ), 2.19 (m, 2H, —CF ₂ CH ₂ - of _{CH 2), 2.0-1.5 (m,} 12H), 1.36 (t, 3H, CH 3 of _O-CH 2 _{CH 3).}

The same as Example 1 except that 2,2-difluoro-4- (1-hydroxycyclohexyl) -butanoic acid ethyl ester was used in place of 2,2-difluoro-5-hydroxy-5-methyl-hexanoic acid ethyl ester. 2,2-difluoro-4- (1-methacryloyloxycyclohexyl) -butanoic acid ethyl ester represented by the following formula (M-6) was obtained (yield 90%, purity 99%).
The ¹ H-NMR data of 2,2-difluoro-4- (1-methacryloyloxycyclohexyl) -butanoic acid ethyl ester is shown below.
¹ H-NMR (measurement solvent: CDCl ₃ , reference material: tetramethylsilane): σ = 6.02 (s, 1H, ═CH ₂ ), 5.53 (s, 1H, ═CH ₂ ), 4.33 (q, 2H, _CH 2 of _{O-CH 2 CH 3),} 2.20 (m, 2H, -CF 2 CH 2 - of _{CH 2), 2.0-1.5 (m,} 12H), 1. 35 (t, 3H, _CH 3 of _O-CH 2 _{CH 3).}

Example 7 Synthesis of 2,2,2-trifluoroethyl 2,2-difluoro-4- (1-methacryloyloxycyclohexyl) -butanoate (M-7) 2.38 wt% in a 500 mL three-necked flask 300 mL of tetramethylammonium hydroxide aqueous solution was added. 5 g of 2,2-difluoro-4- (1-methacryloyloxycyclohexyl) -butanoic acid ethyl ester obtained in Example 6 was added at room temperature and stirred for 2 hours. After confirming complete dissolution and confirming that the raw material had disappeared by gas chromatography, dilute hydrochloric acid was added to adjust the pH of the aqueous layer to 5. 100 mL of ethyl acetate was added, the organic layer was recovered by a liquid separation operation, and the aqueous layer was further extracted three times with 100 mL of ethyl acetate. All the obtained organic layers were combined, 0.01 g of 4-methoxyphenol was added, and the mixture was concentrated under reduced pressure. The obtained concentrated liquid was purified by silica gel chromatography (developing solvent: n-hexane / ethyl acetate = 1/1, acetic acid added as 2 w% as a buffer), and represented by the following formula (m-7) 2,2 1.9 g of -difluoro-4- (1-methacryloyloxycyclohexyl) -butanoic acid was obtained (yield 42%, purity 83%).
The ¹ H-NMR data of 2,2-difluoro-4- (1-methacryloyloxycyclohexyl) -butanoic acid are shown below.
¹ H-NMR (measurement solvent: CDCl ₃ , reference material: tetramethylsilane): σ = 6.01 (s, 1H, ═CH ₂ ), 5.50 (s, 1H, ═CH ₂ ), 2.20 _{(m, 2H, -CF 2 CH} 2 - of _{CH 2), 2.0-1.5 (m,} 12H), 1.35 (t, 3H, CH 3 of _O-CH 2 _{CH 3).}

200 mL of dichloromethane, 2.79 g (0.022 mol) of oxalyl chloride and 1 drop of N, N-dimethylformamide were added to a 300 mL three-necked flask, and the temperature of the reaction solution was adjusted to 0 ° C. with ice cooling. 5.81 g (0.02 mol) of the compound (m-7) was dissolved in 100 mL of dichloromethane, and this was slowly added dropwise to the reaction solution so that the temperature did not rise. After completion of the dropping, the mixture was stirred at 0 degree for 30 minutes, and further stirred at room temperature for 4 hours. After confirming the disappearance of the raw materials by gas chromatography, the reaction solution was cooled to 0 ° C., and 2.22 g (0.022 mol) of triethylamine was slowly added dropwise so that the temperature of the reaction solution did not rise. After completion of the dropwise addition, the mixture was stirred for 10 minutes, and 2.40 g (0.024 mol) of 2,2,2-trifluoroethanol was added. After stirring at room temperature for 2 hours, the progress of the reaction was confirmed by gas chromatography, and the reaction solution was concentrated under reduced pressure using an evaporator. 50 g of n-hexane is added to the concentrate, and the mixture is passed through a short column (silica gel 50 g, developing solvent: n-hexane) with n-hexane, and represented by the following formula (M-7) 2,2 , 2-trifluoroethyl 2,2-difluoro-4- (1-methacryloyloxycyclohexyl) -butanoate was obtained (yield 90%, purity 94%).
¹ H-NMR data of 2,2,2-trifluoroethyl 2,2-difluoro-4- (1-methacryloyloxycyclohexyl) -butanoate are shown below.
¹ H-NMR (measurement solvent: CDCl ₃ , reference material: tetramethylsilane): σ = 6.02 (s, 1H, ═CH ₂ ), 5.53 (s, 1H, ═CH ₂ ), 4.69 (q, 2H, _CH 2 of _{O-CH 2 CF 3),} 2.20 (m, 2H, -CF 2 CH 2 - of _{CH 2), 2.0-1.5 (m,} 12H), 1. 35 (t, 3H, _CH 3 of _O-CH 2 _{CH 3).}

[Example 8] Synthesis of 2,2,3,3-tetrafluoro-6- (methacryloyloxy) -6-methyl-heptanoic acid methyl ester (M-8) In a 1000 mL three-necked flask, 3-chloro- 14.6 g (0.075 mol) of methyl 2,2,3,3-tetrafluoropropionate, 9.69 g (0.113 mol) of 2-methyl-3-buten-2-ol, sodium hydrosulfite 19.59 g (0.113 mol), 9.45 g (0.113 mol) of sodium hydrogen carbonate and 300 mL of dimethyl sulfoxide were suspended by stirring and heated to 75 ° C. in an oil bath. Stir for 6 hours. After confirming the completion of the reaction by gas chromatography, the reaction solution was cooled to room temperature, and the reaction solution was added to 300 mL of 0 degree ultrapure water so that the temperature did not rise. Thereafter, 200 mL of ethyl acetate was added to the mixture, and the organic layer was recovered by a liquid separation operation. Further, 200 mL of ethyl acetate was added to the aqueous layer to perform a liquid separation operation, and the operation of recovering the organic layer was repeated three times in total, and all the recovered organic layers were combined and concentrated under reduced pressure using an evaporator. 200 mL of ethyl acetate was added to the concentrated liquid, and 300 mL of ultrapure water was further added as a cleaning liquid for liquid separation, and the aqueous layer was discarded. 300 mL of ultrapure water was added to the organic layer for liquid separation, and the operation of discarding the aqueous layer was performed three times. The organic layer washed with ultrapure water was concentrated under reduced pressure using an evaporator, and purified by silica gel column chromatography (developing solvent: n-hexane / ethyl acetate = 4/1) to obtain the following formula (m-8). 6.97 g of 2,2,3,3-tetrafluoro-6-hydroxy-6-methyl-heptanoic acid methyl ester represented was obtained (yield 40%, purity 98%).
¹ H-NMR data of 2,2,3,3-tetrafluoro-6-hydroxy-6-methyl-heptanoic acid methyl ester is shown below.
¹ H-NMR (measurement solvent: CDCl ₃ , reference substance: tetramethylsilane): ¹ H-NMR (measurement solvent: CDCl ₃ , reference substance: tetramethylsilane): σ = 3.95 (s, 3H, O— CH ₃ CH ₃ ), 2.19 (m, 2H, —CF ₂ CH ₂ — CH ₂ ), 1.73 (m, 2H, C—CH ₂ CH ₂ ), 1.27 (s, 6H , C (CH ₃ ) CH ₃ ).

In a 100 mL three-necked flask, 40 g of dichloromethane and 4.64 g (0.02 mol) of the above 2,2,3,3-tetrafluoro-6-hydroxy-6-methyl-heptanoic acid methyl ester (m-8) 1,4-diazabicyclo [2.2.2] octane (DABCO) 2.69 g (0.024 mol) was added, the inside of the reactor was purged with nitrogen, and then cooled to 0 ° C. Thereto, 2.67 g (0.021 mol) of methacrylic acid chloride dissolved in 20 g of dichloromethane was slowly added dropwise so that the reaction solution temperature did not rise. After the completion of the dropwise addition, the mixture was stirred for 30 minutes while maintaining 0 degree. After confirming the completion of the reaction by gas chromatography, the reaction solution was cooled to 0 degree, and 100 ml of n-hexane cooled to 0 degree and 20 g of silica gel were added to terminate the reaction. The reaction solution was passed through a short column (silica gel 50 g, developing solvent: n-hexane) with n-hexane to give 2,2,3,3-tetrafluoro- represented by the following formula (M-8). 5.53 g of 6- (methacryloyloxy) -6-methyl-heptanoic acid methyl ester was obtained (yield 88%, purity 99%).
The ¹ H-NMR data of 2,2,3,3-tetrafluoro-6- (methacryloyloxy) -6-methyl-heptanoic acid methyl ester is shown below.
¹ H-NMR (measurement solvent: CDCl ₃ , reference material: tetramethylsilane): σ = 6.00 (s, 1H, ═CH ₂ ), 5.51 (s, 1H, ═CH ₂ ), 3.95 (s, 3H, _CH 3 of _{O-CH 3), 2.20 (} m, 2H, -CF 2 CH 2 - of _{CH 2), 2.00 (m,} 2H, CH 2 of C-CH _{2), 1.90 (s, 3H, CH 3} -C), 1.54 (s, 6H, CH 3 of C (CH _3)).

<[A] Synthesis of polymer>
The monomers used for the synthesis of the [A] polymer and the later-described [B] polymer are the above formulas (M-1) to (M-8) and the following formulas (M-9) to (M-23). Indicated.
[Example 9]
5.00 g of compound (M-1) was dissolved in 10 g of 2-butanone, and 0.09 g of 2,2′-azobis (2-isobutyronitrile) was further charged into a 100 mL three-necked flask. After purging with nitrogen for 30 minutes, the reaction kettle was heated to 80 ° C. with stirring, the start of overheating was taken as the polymerization start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization, the polymerization solution was cooled with water to 30 ° C. or less, and concentrated under reduced pressure until the weight of the polymerization solution became 12.5 g using an evaporator. The polymerization solution was slowly added to 75 g of n-hexane cooled to 0 ° C. to precipitate a solid content. The mixture was filtered, the solid content was washed with n-hexane, and the resulting flour was vacuum dried at 40 degrees for 15 hours. White powder was obtained in 3.75 g (75% yield). Mw of this polymer was 9,400 and Mw / Mn was 1.50.

[Examples 10-22, Comparative Examples 1-6]
The polymers (A-2) to (A-14) and (a-1) to (a-6) were operated in the same manner as in Example 9 except that a predetermined amount of the monomers listed in Table 1 were blended. Got. In addition, Table 1 shows the Mw, Mw / Mn, yield (%), the content of the structural unit derived from each monomer in each polymer, and the degree of dispersion of each polymer obtained.

<[B] Synthesis of polymer>
[Synthesis Example 1]
Compound (M-21) 119.2 g (15 mol%), Compound (M-16) 41.07 g (35 mol%), Compound (M-22) 15.75 g (15 mol%), Compound (M-23) 11.16 g (10 mol%) and compound (M-20) 20.10 g (25 mol%) were dissolved in 100 g of 2-butanone, and AIBN 3.43 g was added to prepare a monomer solution. A 1000 mL three-necked flask containing 100 g of 2-butanone was purged with nitrogen for 30 minutes, then heated to 80 ° C. with stirring, and the prepared monomer solution was added dropwise over 3 hours using a dropping funnel. The dripping start was set as the polymerization reaction start time, and the polymerization reaction was carried out for 6 hours. After completion of the polymerization reaction, the polymerization solution was cooled with water and cooled to 30 ° C. or lower. The polymerization solution was concentrated under reduced pressure using an evaporator until the weight of the polymerization solution reached 150 g. Thereafter, the concentrated solution was poured into a mixed solution of 760 g of methanol and 40 g of water to precipitate a slime-like white solid. The liquid part was removed by decantation, and the collected solid was vacuum-dried at 60 ° C. for 15 hours to obtain 61.3 g of polymer (B-1) as a white powder (yield 88%). Mw was 9,300 and Mw / Mn was 1.6. As a result of ¹³ C-NMR analysis, the structural unit derived from the compound (M-21): the structural unit derived from the compound (M-16): the structural unit derived from (M-22): the structure derived from (M-23) The content ratio of the structural unit derived from unit: (M-20) was 16: 26: 19: 11: 28 (mol%).

<Preparation of radiation-sensitive resin composition>
The [C] acid generator, acid diffusion controller and solvent used in the preparation of the radiation sensitive resin composition are as follows.

<[C] acid generator>
Compound represented by the following formula (C-1)

<Acid diffusion control agent>
A compound represented by the following formula (D-1).

<Solvent>
Hereinafter, the solvents used in Examples and Comparative Examples are shown.
(E-1) Acetic acid propylene glycol monomethyl ether (E-2) Cyclohexanone (E-3) γ-butyrolactone

[Example 23]
100 parts by mass of the polymer (A-1) obtained in Example 9, 8 parts by mass of the acid generator (C-1), 1.2 parts by mass of the acid diffusion controller (D-1), and the solvent (E- 1) 3900 parts by mass were mixed, and the resulting mixed solution was filtered through a filter having a pore size of 0.20 μm to prepare a radiation sensitive resin composition.

[Examples 24-36, Comparative Examples 7 and 8]
Each radiation sensitive resin composition was prepared by performing the same operation as in Example 23 except that the formulation shown in Table 2 was used.

<Evaluation>
The following evaluation results are shown in Table 2.

[Evaluation of acid dissociation]
After spin coating the composition for the lower layer film (trade name “ARC29”, manufactured by Nissan Chemical Co., Ltd.) and the trade name “CLEAN TRACK ACT8” on an 8-inch silicon wafer, baking was performed at 205 ° C. for 60 seconds. By carrying out, the coating film with a film thickness of 78 nm was formed. Next, after spin-coating the radiation sensitive resin composition prepared in Examples 21 to 33 using the trade name “CLEAN TRACK ACT8” and performing soft baking (SB) at a predetermined baking temperature for 50 seconds. By cooling at 23 ° C. for 30 seconds, a 120 nm thick photoresist coating film was formed.
Next, using an ArF exposure apparatus (trade name “S306C”, manufactured by NIKON), NA: 0.75, Outerσ = 0.6, conventional optical conditions, without a mask, a 0.5 cm square bulk pattern is formed. Projected onto the substrate. After a post-exposure bake (PEB) at 95 degrees for 50 seconds on a hot plate of trade name “CLEAN TRACK ACT8”, a 2.38% tetramethylammonium hydroxide aqueous solution was used as a developer at the LD nozzle of the development unit. Paddle development (30 seconds) and rinse with ultrapure water. A substrate on which a resist pattern was formed was obtained by spin-drying at 2000 rpm for 15 seconds.
The film thickness of the photoresist where the bulk pattern of 0.5 cm square was projected was measured, and the exposure amount when the film thickness became 0 nm was defined as “Eth” to evaluate the acid dissociation degree. It is judged that the acid dissociation degree is higher as Eth is lower.

  As shown in Table 2, it was found that the radiation sensitive resin compositions of Examples 23 to 36 had a higher degree of acid dissociation than Comparative Examples 7 and 8.

[Example 37]
5 parts by mass of the polymer (A-1) obtained in Example 9, 100 parts by mass of the polymer (B-1) obtained in Synthesis Example 1, 8 parts by mass of the acid generator (C-1), acid diffusion 1.2 parts by mass of the control agent (D-1), 2,590 parts by mass of the solvent (E-1), 1,110 parts by mass of (E-2), and 200 parts by mass of (E-3) were obtained. The obtained mixed solution was filtered through a filter having a pore size of 0.20 μm to prepare a radiation sensitive resin composition.

[Examples 38 to 50, Comparative Examples 9 to 14]
Each radiation sensitive material was subjected to the same operation as in Example 37, except that the blending formulation shown in Table 3 was used for the [A] component, [B] polymer, [C] acid generator, and [D] acid diffusion controller. A functional resin composition was prepared.

<Evaluation>
The following evaluation results are shown in Table 3.

[Measurement of receding contact angle]
A photoresist film having a film thickness of 100 nm was formed on the substrate using the radiation-sensitive resin compositions prepared in Examples 37 to 50 and Comparative Examples 9 to 14, respectively. Thereafter, the receding contact angle of the formed film was measured in the following procedure using DSA-10 manufactured by KRUS under an environment of room temperature 23 ° C., humidity 45%, and normal pressure.
The DSA-10 needle is cleaned with acetone and isopropyl alcohol before measurement, then water is injected into the needle, and the wafer is set on the wafer stage. The height of the stage is adjusted so that the distance between the wafer surface and the tip of the needle is 1 mm or less, and then water is discharged from the needle to form a 25 μL water droplet on the wafer. And a contact angle was measured every second. From the time when the contact angle was stabilized, an average value was calculated for a total of 20 contact angles, which were set as receding contact angles (degrees).
A film having a film thickness of 100 nm was formed on an 8-inch silicon wafer by the above-mentioned radiation-sensitive resin composition, and a soft contact (SB) was performed at 120 degrees for 50 seconds. "Angle (degree)".
A film with a film thickness of 110 nm was formed on an 8-inch silicon wafer with the above radiation-sensitive resin composition, and SB was performed at 120 degrees for 50 seconds. Thereafter, development was performed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution for 10 seconds using a GP nozzle of a developing device of Clean Electron “ACT8” manufactured by Tokyo Electron Ltd., rinsed with pure water for 15 seconds, and at 2,000 rpm. The receding contact angle of the substrate after the liquid was shaken off was defined as “retracting contact angle (degrees) after 10 seconds development”.
A film with a film thickness of 110 nm was formed on an 8-inch silicon wafer with the above radiation-sensitive resin composition, and SB was performed at 120 degrees for 50 seconds. Thereafter, development was performed with a 2.38 mass% aqueous solution of tetramethylammonium hydroxide for 30 seconds with a GP nozzle of a developing device of Clean Electron “ACT8” manufactured by Tokyo Electron Ltd., rinsed with pure water for 30 seconds, and at 2,000 rpm. The receding contact angle of the substrate that had been shaken off and dried was defined as “30 s post-development receding contact angle (degrees)”.

[Coverage dependency]
A 12-inch silicon wafer was spin-coated with a composition for an underlayer film (trade name “ARC66”, manufactured by Nissan Chemical Co., Ltd.) and trade name “Lithius Pro-i”, and then baked at 205 ° C. for 60 seconds. Was performed to form a coating film having a thickness of 105 nm. Next, each of the radiation-sensitive resin compositions prepared in Examples 37 to 50 and Comparative Examples 9 to 14 was spin-coated using the trade name “CLEAN TRACK ACT12”, and SB was applied for 50 seconds at a predetermined baking temperature. After performing, it cooled at 23 degreeC for 30 second, and formed the coating film with a film thickness of 90 nm.
Next, using an ArF immersion exposure apparatus (trade name “S610C”, manufactured by NIKON), NA = 1.30, Outerσ / innerσ = 0.877 / 0.782, Dipole, and optical conditions of dipolar illumination Thus, exposure was performed through a mask for projecting a bright field (BF) pattern having a 40 nm line / 80 nm pitch (hereinafter, the dimension of the pattern projected by the mask is referred to as a “projection pattern dimension” of the mask. A mask with a pattern size of 40 nm line / 80 nm pitch refers to a mask for projecting a pattern with a 40 nm line / 80 nm pitch, and the bright field is not covered with a mask and the projection light is transmitted. A pattern formed by a mask of the type to be used). After performing post-exposure baking (PEB) for 50 seconds at a predetermined baking temperature on a hot plate of the product name “Lithius Pro-i”, a 2.38% tetramethylammonium hydroxide aqueous solution was added using a GP nozzle of the developing unit. Paddle development (10 seconds) was performed as a developer, and rinsed with ultrapure water. A substrate on which a resist pattern was formed was obtained by spin-drying at 2000 rpm for 15 seconds. At this time, the exposure amount at which a resist pattern having a 40 nm line / 80 nm pitch was formed was defined as the BF optimum exposure amount. In Table 3, (* 1) indicates that a bridge occurred and the BF optimum exposure amount could not be calculated.

  Instead of using the 40 nm line / 80 nm pitch BF pattern forming mask described above, evaluation was performed using a 40 nm line / 80 nm pitch DarkField (DF) pattern forming mask (DarkField is a mask around the pattern. The pattern is formed by a mask that is covered and does not transmit projection light). At that time, the exposure amount at which a resist pattern with a 40 nm line / 80 nm pitch was formed was taken as the DF optimum exposure amount, and the difference between the DF optimum exposure amount and the BF optimum exposure amount was calculated at 100 minutes. The calculation formula is shown below.

(DF optimum exposure amount / BF optimum exposure amount × 100) −100 = difference in optimum exposure amount (%)
When the difference (%) in the optimum exposure amount was −3% to 3% or less, it was evaluated as “good”, and the other range was evaluated as “bad”. In Table 3, (* 2) indicates that a bridge was generated in the DF section observation and could not be evaluated.

[Development defects]
A coating having a film thickness of 110 nm was formed from a radiation-sensitive resin composition on a 12-inch silicon wafer on which a lower antireflection film (Nissan Chemical Co., ARC66) was formed, and SB was performed at 120 degrees for 50 seconds. Next, an ArF excimer laser immersion exposure apparatus (NIKON, NSR S610C) was used for this coating, and the target size was a line and space with a width of 45 nm (NA = 1.3, ratio = 0.800, Dipole) 1L / 1S) was exposed through a mask pattern. After exposure, PEB was performed at 95 ° C. for 50 seconds. Thereafter, development was performed for 10 seconds with a 2.38 mass% tetramethylammonium hydroxide aqueous solution using a GP nozzle of a developing device of Clean Electron “ACT12” manufactured by Tokyo Electron Ltd., rinsed with pure water for 15 seconds, and at 2,000 rpm. The liquid was shaken off and dried to form a positive resist pattern. At this time, the exposure amount for forming 1 L / 1S having a width of 45 nm was determined as the optimum exposure amount. With this optimum exposure amount, 1L / 1S having a line width of 45 nm was formed on the entire surface of the wafer to obtain a defect inspection wafer. Note that a scanning electron microscope (Hitachi High-Technologies Corporation, CC-4000) was used for length measurement. Thereafter, the number of defects on the defect inspection wafer was measured using KLA-Tencor, KLA2810. Furthermore, the defects measured by the company KLA2810 were classified into those judged to be resist-derived and foreign matters derived from the outside. After classification, when the total number of defects determined to be derived from the resist film is less than 100 / wafer, it is “good”, and when it is 100 to 500 / wafer, “slightly good”, 500 / wafer. If it exceeds, it was judged as “bad”.

  As shown in Table 3, it was found that the radiation-sensitive resin composition of the present invention was excellent in hydrophobicity during immersion exposure and became hydrophilic during development to form a resist film having high developer affinity. When the radiation sensitive resin composition of this invention was used, it turned out that coverage dependency improves and a favorable fine pattern can be formed.

  The radiation sensitive resin composition of this invention is used suitably in formation of the resist pattern in the lithography process of various electronic devices, such as a semiconductor device and a liquid crystal device.

Claims (8)

[A] A radiation-sensitive resin composition containing a polymer having a structural unit (I) represented by the following formula (1).

(In Formula (1), R ¹ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ² is an acid dissociable group represented by Formula (2) above.
In formula (2), X is a divalent organic group. n is an integer of 1-4. Q ¹ and Q ² are each independently a hydrogen atom, a fluorine atom, or a monovalent organic group. However, at least one of Q ¹ and Q ² is an electron withdrawing group. When n is 2 or more, the plurality of Q ¹ and Q ² may be the same or different. Y is an alkali dissociable group. ) The radiation-sensitive resin composition according to claim 1, wherein X is a divalent group represented by the following formula (3-1), (3-2), or (3-3).

(In Formula (3-1), R ³ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or 6 to 22 carbon atoms. R ⁴ is an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic group having 6 to 22 carbon atoms. It is an aromatic hydrocarbon group, provided that any two of R ^{3 to} R ⁵ may be bonded to each other to form a ring together with the carbon atom to which they are bonded.
In formula (3-2), R ⁶ and R ⁸ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or 6 carbon atoms. It is a monovalent aromatic hydrocarbon group of ˜22. R ⁷ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{6 to} R ⁸ may be bonded to each other to form a ring together with the carbon atom to which R ⁶ and R ⁸ are bonded.
In formula (3-3), R ⁹ is an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms. It is. R ¹⁰ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. R ¹¹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{9 to} R ¹¹ may be bonded to each other to form a ring together with the carbon atom to which R ¹⁰ and R ¹¹ are bonded.
In formulas (3-1) to (3-3), * indicates a binding site with the ester group in formula (1). Moreover, one part or all part of the hydrogen atom which R < ³ > -R < ¹¹ > has may be substituted. ) The Q ¹ and Q ² are radiation-sensitive resin composition according to claim 1 or claim 2 is a fluorine atom.   [B] The radiation sensitive resin composition according to claim 1, 2 or 3, further comprising a polymer having an acid dissociable group and having no alkali dissociable group. The polymer which has structural unit (I) represented by following formula (1).

(In Formula (1), R ¹ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ² is an acid dissociable group represented by Formula (2) above.
In formula (2), X is a divalent organic group. n is an integer of 1-4. Q ¹ and Q ² are each independently a hydrogen atom, a fluorine atom, or a monovalent organic group. However, at least one of Q ¹ and Q ² is an electron withdrawing group. When n is 2 or more, the plurality of Q ¹ and Q ² may be the same or different. Y is an alkali dissociable group. ) The polymer according to claim 5, wherein X is a divalent group represented by the following formula (3-1), (3-2) or (3-3).

(In Formula (3-1), R ³ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or 6 to 22 carbon atoms. R ⁴ is an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic group having 6 to 22 carbon atoms. It is an aromatic hydrocarbon group, provided that any two of R ^{3 to} R ⁵ may be bonded to each other to form a ring together with the carbon atom to which they are bonded.
In formula (3-2), R ⁶ and R ⁸ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or 6 carbon atoms. It is a monovalent aromatic hydrocarbon group of ˜22. R ⁷ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{6 to} R ⁸ may be bonded to each other to form a ring together with the carbon atom to which R ⁶ and R ⁸ are bonded.
In formula (3-3), R ⁹ is an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms. It is. R ¹⁰ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. R ¹¹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{9 to} R ¹¹ may be bonded to each other to form a ring together with the carbon atom to which R ¹⁰ and R ¹¹ are bonded.
In formulas (3-1) to (3-3), * indicates a binding site with the ester group in formula (1). Moreover, one part or all part of the hydrogen atom which R < ³ > -R < ¹¹ > has may be substituted. ) A compound represented by the following formula (4).

(In Formula (4), R ¹ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ² is an acid dissociable group represented by Formula (2) above.
In formula (2), X is a divalent organic group. n is an integer of 1-4. Q ¹ and Q ² are each independently a hydrogen atom, a fluorine atom, or a monovalent organic group. However, at least one of Q ¹ and Q ² is an electron withdrawing group. When n is 2 or more, the plurality of Q ¹ and Q ² may be the same or different. Y is an alkali dissociable group. ) The compound according to claim 7, wherein X is a divalent group represented by the following formula (3-1), (3-2), or (3-3).

(In Formula (3-1), R ³ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or 6 to 22 carbon atoms. R ⁴ is an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic group having 6 to 22 carbon atoms. It is an aromatic hydrocarbon group, provided that any two of R ^{3 to} R ⁵ may be bonded to each other to form a ring together with the carbon atom to which they are bonded.
In formula (3-2), R ⁶ and R ⁸ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or 6 carbon atoms. It is a monovalent aromatic hydrocarbon group of ˜22. R ⁷ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{6 to} R ⁸ may be bonded to each other to form a ring together with the carbon atom to which R ⁶ and R ⁸ are bonded.
In formula (3-3), R ⁹ is an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms. It is. R ¹⁰ is a single bond, an alkanediyl group having 1 to 4 carbon atoms, a divalent alicyclic group having 4 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 22 carbon atoms. R ¹¹ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a monovalent alicyclic group having 4 to 20 carbon atoms, or a monovalent aromatic hydrocarbon group having 6 to 22 carbon atoms. However, any two of R ^{9 to} R ¹¹ may be bonded to each other to form a ring together with the carbon atom to which R ¹⁰ and R ¹¹ are bonded.
In formulas (3-1) to (3-3), * indicates a binding site with the ester group in formula (1). Moreover, one part or all part of the hydrogen atom which R < ³ > -R < ¹¹ > has may be substituted. )