JP2013032434A - Polymer, resist composition and method for forming resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist composition having excellent lithography properties and pattern shapes and a new compound useful as the resist composition, and to provide a method for forming a resist pattern using the resist composition.SOLUTION: A polymer has an anionic site which produces an acid by exposure in at least one terminal of a main chain, and a structural unit (a0) containing a cyclic group that contains -SO-. A resist composition containing the polymer and a method for forming a resist pattern using the resist composition are provided.

Description

  The present invention relates to a polymer useful as a resist composition, a resist composition containing the polymer, and a resist pattern forming method using the resist composition.

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

Resist materials are required to have lithography characteristics such as sensitivity to these exposure light sources and resolution capable of reproducing patterns with fine dimensions.
As a resist material satisfying such requirements, a chemically amplified resist composition containing a base material component whose solubility in a developing solution is changed by the action of an acid and an acid generator component that generates an acid upon exposure is used. ing.
For example, when the developer is an alkali developer (alkaline development process), the positive chemically amplified resist composition includes a resin component (base resin) whose solubility in an alkali developer is increased by the action of an acid, and acid generation. What contains an agent component is generally used. When a resist film formed using such a resist composition is selectively exposed at the time of resist pattern formation, an acid is generated from the acid generator component in the exposed portion, and the alkali developer of the resin component is generated by the action of the acid. As a result, the exposed area becomes soluble in an alkaline developer. Then, a positive pattern in which an unexposed portion remains as a pattern is formed. Here, as the base resin, a resin whose polarity is increased by the action of an acid is used, and the solubility in an alkali developer is increased while the solubility in an organic solvent is decreased. When a process using an organic solvent-containing developer (organic developer) (hereinafter sometimes referred to as a solvent development process or a negative development process) is applied instead of an alkali development process, Solubility in organic developers is reduced. Therefore, in the solvent development process, the unexposed portion of the resist film is dissolved and removed by the organic developer, and a negative resist pattern in which the exposed portion remains as a pattern is formed. For example, Patent Document 1 proposes a negative development process and a resist composition used therefor.

  At present, as a base resin of a resist composition used in ArF excimer laser lithography and the like, a resin (acrylic resin) having a structural unit derived from a (meth) acrylate ester in its main chain because of its excellent transparency near 193 nm. Resin) is generally used (see, for example, Patent Document 2).

The base resin usually has a plurality of structural units in order to improve lithography properties and the like. For example, in the case of a resin component in which the polarity of the resin is increased by the action of an acid, it usually has a structural unit having an acid-decomposable group that is decomposed by the action of an acid generated from the acid generator component and increases in polarity. Those having a plurality of structural units such as a structural unit having a polar group such as a hydroxyl group and a structural unit having a lactone structure are used. In particular, a structural unit having a polar group is widely used because it increases the affinity with an alkali developer and contributes to an improvement in resolution.
Recently, a base resin having a structural unit containing a cyclic group containing a —SO ₂ — structure has been proposed (see, for example, Patent Documents 3 and 4). Such a base resin is said to contribute to the improvement of resist pattern shape such as lithography characteristics such as mask reproducibility and roughness reduction. Roughness means a rough surface of the resist pattern and causes a defective shape of the resist pattern. For example, line width roughness (line width roughness (LWR)) causes a shape defect typified by non-uniform line width in a line-and-space pattern. The defective shape of the resist pattern may adversely affect the formation of a fine semiconductor element, and the improvement becomes more important as the pattern becomes finer.

The polymer used for the base resin as described above is usually produced by radical polymerization of monomers having various functions. As the polymerization initiator in radical polymerization, azo polymerization initiators such as azobisisobutyronitrile (AIBN) and dimethyl 2,2′-azobis (2-methylpropionate) are generally used.
The azo polymerization initiator is decomposed by heat or light to generate nitrogen gas and radicals. And a polymer is synthesize | combined by addition polymerization of monomers by the effect | action of this radical. Therefore, a partial structure of an azo polymerization initiator is introduced at the end of the synthesized polymer.
In recent years, paying attention to the partial structure of a polymerization initiator introduced at the polymer terminal, a polymerization initiator using a base-dissociable group that is a functional group as the partial structure, and a weight obtained using the polymerization initiator are obtained. Coalescence etc. are indicated (refer to patent documents 5).

JP 2009-025723 A JP 2003-241385 A JP 2009-062491 A JP 2010-134417 A JP 2010-37528 A

In the future, there is a demand for new materials that can be used for lithography applications as further progress in lithography technology and expansion of application fields progress. For example, as pattern miniaturization progresses, the resist material can be a hole pattern such as roughness (LWR (line width roughness: line width non-uniformity) for line patterns) as well as sensitivity and resolution. Further improvement of various lithography properties and pattern shapes such as roundness, mask reproducibility, and exposure margin is required. However, the resist material using the base resin described in Patent Documents 2 to 5 cannot sufficiently satisfy the required lithography characteristics and pattern shape.
The present invention has been made in view of the above circumstances, and is a resist composition excellent in lithography characteristics and pattern shape, a novel polymer useful for the resist composition, and resist pattern formation using the resist composition It is an object to provide a method.

In order to solve the above problems, the present invention employs the following configuration.
That is, the first aspect of the present invention has a structural unit (a0) having an anion moiety that generates an acid upon exposure at the end of at least one end of the main chain, and a —SO ₂ — containing cyclic group. It is a polymer.
The second aspect of the present invention is a resist composition containing the polymer of the first aspect.
According to a third aspect of the present invention, a resist film is formed on a support using the resist composition of the second aspect, the resist film is exposed, and the resist film is developed to form a resist. It is a resist pattern formation method including the process of forming a pattern.

In the present specification and claims, “exposure” is a concept including general irradiation of radiation.
“Structural unit” means a monomer unit (monomer unit) constituting a polymer compound (resin, polymer, copolymer).
“Aliphatic” is a relative concept with respect to aromatics, and is defined to mean groups, compounds, etc. that do not have aromaticity.
Unless otherwise specified, the “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups.
The “alkylene group” includes linear, branched, and cyclic divalent saturated hydrocarbon groups unless otherwise specified. The same applies to the alkyl group in the alkoxy group.
The “halogenated alkyl group” is a group in which part or all of the hydrogen atoms of the alkyl group are substituted with halogen atoms, and the “halogenated alkylene group” is the part of or all of the hydrogen atoms in the alkylene group is a halogen atom. The halogen atom includes a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
The “fluorinated alkyl group” is a group in which part or all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms, and the “fluorinated alkylene group” is the part or all of the hydrogen atoms of the alkylene group is fluorine atoms. A group substituted with

  ADVANTAGE OF THE INVENTION According to this invention, the resist composition excellent in the lithography characteristic and pattern shape, the novel polymer useful for this resist composition, and the resist pattern formation method using this resist composition can be provided.

≪Polymer≫
The polymer of the present invention has a structural unit (a0) having an anion moiety that generates an acid upon exposure at the terminal of at least one end of the main chain, and a —SO ₂ — containing cyclic group.
The polymer is obtained by polymerizing a monomer containing at least a monomer for deriving the structural unit (a0) by radical polymerization, anionic polymerization or the like using a specific polymerization initiator. Therefore, the “anion site that generates an acid upon exposure” in the present invention is a residue derived from a polymerization initiator and not a structure derived from a monomer that derives a structural unit. In the polymer, “at least one terminal of the main chain” means a site where a residue derived from the polymerization initiator is bonded to one end of the molecular chain, and the terminal of the side chain branched from the main chain. (That is, the end of the structure forming the structural unit) is clearly different.

<Anion site>
The “anion site that generates an acid upon exposure” refers to an ionic structural site in a sulfonium salt or an iodonium salt that is an acid generator component that generates an acid upon exposure, generally used with a base resin in a chemically amplified resist composition. Is preferred. The acid anion generated by exposure is preferably a sulfonic acid anion, a carboxylic acid anion, a sulfonylimide anion, a bis (alkylsulfonyl) imide anion, or a tris (alkylsulfonyl) methide anion. These acid anions are generated from the end of the main chain of the polymer by exposure.
Especially, it is preferable that this anion site | part has a group represented by the following general formula (an1).

［式中、Ｒ^ｆ１及びＲ^ｆ２はそれぞれ独立に水素原子、アルキル基、フッ素原子、又はフッ素化アルキル基である。ｒ^０は０〜８の整数である。］

[Wherein, R ^f1 and R ^f2 each independently represent a hydrogen atom, an alkyl group, a fluorine atom, or a fluorinated alkyl group. r ⁰ is an integer of 0-8. ]

In the formula (an1), the alkyl group of R ^f1 and R ^f2 is preferably an alkyl group having 1 to 5 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, or an n-butyl group. , Isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like.
Examples of the fluorinated alkyl group of R ^{f1, R f2,} the ^{R f1,} group in which part or entirely substituted with fluorine atoms of the hydrogen atoms of the alkyl group of ^{R f2} are preferred.
R ^f1 and R ^f2 are preferably a fluorine atom or a fluorinated alkyl group.
In the formula (an1), r ⁰ is preferably an integer of 1 to 4, and more preferably 1 or 2.

In the polymer of the present invention, at least one terminal of the main chain has a group represented by the following general formula (I-1) (hereinafter this group is also referred to as “terminal group (I-1)”). Is preferred.
By having the terminal group (I-1), the polymer of the present invention has an acid generating ability to generate an acid upon exposure. That is, the terminal group (I-1) has a sulfonium salt moiety at the terminal, so that sulfonic acid is generated by exposure.

［式中、Ｒ^１は炭素数１〜１０の炭化水素基であり、Ｚは炭素数１〜１０の炭化水素基又はシアノ基であり、Ｒ^１とＺとは相互に結合して環を形成していてもよい。Ｘは２価の連結基であって、−Ｏ−Ｃ（＝Ｏ）−、−ＮＨ−Ｃ（＝Ｏ）−、及び−ＮＨ−Ｃ（＝ＮＨ）−のいずれかを、少なくとも式中のＱと接する末端に有する。ｐは１〜３の整数である。Ｑは（ｐ＋１）価の炭化水素基であり、ｐが１の場合のみ、Ｑは単結合であってもよい。Ｒ^２は単結合、置換基を有していてもよいアルキレン基、又は置換基を有していてもよい芳香族基であり、ｑは０又は１であり、ｒは０〜８の整数である。Ｍ^＋は有機カチオンである。］

[Wherein, R ¹ is a hydrocarbon group having 1 to 10 carbon atoms, Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group, and R ¹ and Z are bonded to each other to form a ring. You may do it. X is a divalent linking group, and at least one of —O—C (═O) —, —NH—C (═O) —, and —NH—C (═NH) — It is at the end that contacts Q. p is an integer of 1 to 3. Q is a (p + 1) -valent hydrocarbon group, and Q may be a single bond only when p is 1. R ² is a single bond, an alkylene group which may have a substituent, or an aromatic group which may have a substituent, q is 0 or 1, and r is an integer of 0 to 8. is there. M ⁺ is an organic cation. ]

In the formula ^{(I-1), R} 1 is a hydrocarbon group having 1 to 10 carbon atoms. The hydrocarbon group having 1 to 10 carbon atoms may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group, preferably an aliphatic hydrocarbon group, and a monovalent aliphatic group. More preferably, it is a group saturated hydrocarbon group (alkyl group).
More specifically, examples of the alkyl group include a linear or branched alkyl group and an aliphatic hydrocarbon group containing a ring in the structure.
The linear alkyl group preferably has 1 to 8 carbon atoms, more preferably 1 to 5 carbon atoms, and most preferably 1 to 2 carbon atoms. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Among these, a methyl group, an ethyl group or an n-butyl group is preferable, and a methyl group or an ethyl group is particularly preferable.
The branched alkyl group preferably has 3 to 5 carbon atoms. Specific examples include an isopropyl group, an isobutyl group, a tert-butyl group, an isopentyl group, a neopentyl group, and the like, and an isopropyl group or a tert-butyl group is most preferable.
Examples of the aliphatic hydrocarbon group containing a ring in the structure include a cyclic aliphatic hydrocarbon group (a group obtained by removing one hydrogen atom from an aliphatic hydrocarbon ring), and the cyclic aliphatic hydrocarbon group is the chain described above. Examples include a group that is bonded to the terminal of the chain-like aliphatic hydrocarbon group or is interposed in the middle of the chain-like aliphatic hydrocarbon group.
The cyclic aliphatic hydrocarbon group preferably has 3 to 8 carbon atoms, and more preferably 4 to 6 carbon atoms. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane.
The cyclic aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, and an oxygen atom (= O).

In said formula (I-1), Z is a C1-C10 hydrocarbon group or a cyano group (-CN).
Examples of the hydrocarbon group having 1 to 10 carbon atoms Z, the same as the hydrocarbon group having 1 to 10 carbon atoms of the R ¹ can be mentioned.
R ¹ and Z may be bonded to each other to form a ring. Specifically, R ¹ and Z are each independently a linear or branched alkyl group, and the end of R ^{1 and} the end of Z are bonded to each other to form a ring. Also good. As the ring to be formed, a ring having 3 to 8 carbon atoms is preferable, and cyclopentane, cyclohexane, cycloheptane or cyclooctane is particularly preferable.
Among them, R ¹ and Z in the present invention include a combination of a methyl group and a methyl group, a combination of an ethyl group and an ethyl group, a combination of a methyl group and a cyano group, a combination of an ethyl group and a cyano group, A group in which two carbon atoms are removed from cyclopentane formed by bonding to is preferable, R ¹ is a methyl group, and Z is particularly preferably a cyano group.

In the formula (I-1), X is a divalent linking group, and includes —O—C (═O) —, —NH—C (═O) —, and —NH—C (═NH) —. At least at the terminal in contact with Q in the formula. The end in contact with the Q in the formula, when Q is a single bond, the formula (I-1) in the _{- (C (= O) -O} ) q -, R 2, -CF 2 - or SO ₃ ^- It means the end that touches. Even if the bivalent coupling group of X consists only of -O-C (= O)-, -NH-C (= O)-, and -NH-C (= NH)-. Good. Further, X has —O—C (═O) —, —NH—C (═O) —, or —NH—C (═NH) — in addition to the terminal in contact with Q in the formula. May be.
The divalent linking group of X includes only —O—C (═O) —, —NH—C (═O) —, or —NH—C (═NH) —; An optionally divalent hydrocarbon group or a divalent linking group containing a hetero atom, and —O—C (═O) —, —NH—C (═O) —, or —NH—C ( Preferred examples include those composed of a combination with = NH)-.

(Divalent hydrocarbon group which may have a substituent)
In the present invention, the hydrocarbon group having “substituent” means that part or all of the hydrogen atoms in the hydrocarbon group are substituted with groups or atoms other than hydrogen atoms.
The divalent hydrocarbon group which may have a substituent in X may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group may be saturated or unsaturated, and is usually preferably saturated.

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

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

Examples of the aromatic hydrocarbon group in the divalent hydrocarbon group include monovalent groups such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. A divalent aromatic hydrocarbon group obtained by removing one hydrogen atom from the nucleus of the aromatic hydrocarbon of the aromatic hydrocarbon group; a part of carbon atoms constituting the ring of the divalent aromatic hydrocarbon group Is an aromatic hydrocarbon group substituted with a hetero atom such as an oxygen atom, a sulfur atom or a nitrogen atom; benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthyl An arylalkyl group such as an ethyl group, and an aromatic hydrocarbon group obtained by further removing one hydrogen atom from the nucleus of the aromatic hydrocarbon.
The aromatic hydrocarbon group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, and an oxygen atom (= O).

(Divalent linking group containing hetero atom)
As the divalent linking group containing a hetero atom in X, —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O—, — C (═O) —NH—, —NH—, —NH—C (═NH) — (H may be substituted with a substituent such as an alkyl group or an acyl group), —S—, —S (═O) ₂ —, —S (═O) ₂ —O—, “—AO (oxygen atom) —B— (wherein A and B may each independently have a substituent). And a combination of a divalent hydrocarbon group which may have a substituent and a divalent linking group containing a hetero atom, and the like. Examples of the divalent hydrocarbon group which may have a substituent include those similar to the divalent hydrocarbon group which may have a substituent described above, and may be linear or branched. Or an aliphatic hydrocarbon group containing a ring in the structure thereof.

In the case of -NH-, the substituent (alkyl group, acyl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and more preferably 1 to 5 carbon atoms. It is particularly preferred.
In the case of “A-O-B”, A and B are each independently a divalent hydrocarbon group which may have a substituent.

The hydrocarbon group in A may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group for A may be saturated or unsaturated, and is usually preferably saturated.
Specific examples of the aliphatic hydrocarbon group for A include a linear or branched aliphatic hydrocarbon group, and an aliphatic hydrocarbon group containing a ring in the structure. These are the same as above.
Among these, as A, a linear aliphatic hydrocarbon group is preferable, a linear alkylene group is more preferable, a linear alkylene group having 2 to 5 carbon atoms is further preferable, and an ethylene group is most preferable.

Examples of the hydrocarbon group for B include the same divalent hydrocarbon groups as those described above for A.
B is preferably a linear or branched aliphatic hydrocarbon group, particularly preferably a methylene group or an alkylmethylene group.
The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.

In the case where X consists of only one of -O-C (= O)-, -NH-C (= O)-, and -NH-C (= NH)-, X is -O-C (= O)-or -NH-C (= O)-is preferred. At this time, the carbon atom (C) in —O—C (═O) — or the carbon atom (C) in —NH—C (═O) — is directly bonded to the carbon atom bonded to R ¹ and Z. Bonding is preferred.
In addition, X is a combination of the above-described divalent group and any one of —O—C (═O) —, —NH—C (═O) —, and —NH—C (═NH) —. In some cases, X is a linear or branched aliphatic hydrocarbon group having 1 to 5 carbon atoms, or a divalent linking group containing a hetero atom, -O-C (= O)-,- A combination with any of NH—C (═O) — and —NH—C (═NH) — is preferable; selected from a divalent linking group containing a methylene group, an ethylene group, and —NH—. More preferably, it is a combination of one or more linking groups and any of —O—C (═O) —, —NH—C (═O) —, and —NH—C (═NH) —; It is particularly a combination of two or more groups selected from an ethylene group, —O—C (═O) —, and —NH—C (═O) —. Masui.

In the formula (I-1), p is an integer of 1 to 3, and is preferably 1.
When p is 2 or 3, the ratio of the sulfonic acid moiety (SO ₃ ⁻ ) that can function and generate as an acid in the polymer increases, and the acid generating ability improves.

In the formula (I-1), Q is a (p + 1) -valent hydrocarbon group, and Q may be a single bond only when p is 1.
When p is 1, Q is a single bond or a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include those similar to those having no substituent among the “divalent hydrocarbon groups optionally having a substituent” mentioned in X above. In particular, when p is 1, Q is preferably a single bond or a divalent aliphatic hydrocarbon group, more preferably a single bond or a chain or branched alkylene group, a single bond, Or a methylene group or an ethylene group is more preferable, and a single bond or an ethylene group is particularly preferable.
When p is 2, Q is a trivalent hydrocarbon group, and when p is 3, Q is a tetravalent hydrocarbon group. As the trivalent or tetravalent hydrocarbon group, among the “divalent hydrocarbon group optionally having substituent (s)” mentioned in X above, a divalent hydrocarbon group having no substituent is further selected. The thing remove | excluding one or two hydrogen atoms is mentioned, Especially, it is preferable that it is a trivalent or tetravalent aliphatic hydrocarbon group.
Specific examples in the case where Q is a (p + 1) -valent hydrocarbon group are shown below.

In the formula (I-1), q is 0 or 1. The case where q is 0 means that-(C (= O) -O) _{q- in} the formula is a single bond.
q is preferably 1 when the divalent linking group of X described above does not have —O—C (═O) —, and the divalent linking group of X described above is —O—C. When it has (= O)-, it is preferably 0.

In Formula (I-1), R ² represents a single bond, an alkylene group that may have a substituent, or an aromatic group that may have a substituent.
The alkylene group for R ² may be linear or cyclic. Examples of such an alkylene group include a “linear or branched aliphatic hydrocarbon group” in the divalent hydrocarbon group which may have a substituent of X described above, “a ring in the structure”. The same thing as "the aliphatic hydrocarbon group to contain" is mentioned. Among them, the alkylene group R ^2, preferably a linear alkylene group having 1 to 10 carbon atoms, a methylene group or an ethylene group is more preferable.
The aromatic group which may have a substituent for R ² may be an aromatic hydrocarbon group or an aromatic group (heterocyclic compound) containing an atom other than a carbon atom in the ring structure. Good.
Examples of the aromatic hydrocarbon group include those similar to the “aromatic hydrocarbon group” in the above-described divalent hydrocarbon group which may have a substituent of X. The aromatic hydrocarbon group for R ² is preferably a group obtained by further removing one or more hydrogen atoms from a phenyl group or a naphthyl group. In the aromatic hydrocarbon group of R ² , some or all of the hydrogen atoms are alkyl groups having 1 to 5 carbon atoms, fluorine atoms, fluorinated alkyl groups having 1 to 5 carbon atoms, oxygen atoms (= O), and the like. It may be substituted, and in particular, it is preferably substituted with a fluorine atom.
As the aromatic group containing an atom other than a carbon atom in the ring structure, a group in which two or more hydrogen atoms have been removed from a heterocyclic ring such as quinoline, pyridine, oxol, and imidazole is preferable.
Among these, R ² is preferably an aromatic group which may have a single bond or a substituent.

In said formula (I-1), r is an integer of 0-8. The case where r is 0 means that — (CF ₂ ) _r — in the formula is a single bond.
r is preferably an integer of 1 to 8, more preferably an integer of 1 to 4, even more preferably when R ² described above is a single bond or an alkylene group which may have a substituent. Is 1 or 2, and is preferably 0 when R ² is an aromatic group which may have a substituent.

  Below, the suitable specific example of group represented by general formula (I-1) is shown.

［式中、Ｒ^１、Ｚ、Ｑ、ｐ、Ｍ^＋は前記のものと同じ意味である。Ｘ^０１は単結合又は置換基を有していてもよいアルキレン基であり、Ｒ^２１は単結合又は置換基を有していてもよいアルキレン基であり、Ｘ^０２は置換基を有していてもよいアルキレン基であり、Ｒ^２２は置換基を有していてもよい芳香族基である。］

[Wherein, R ¹ , Z, Q, p and M ⁺ have the same meaning as described above. X ⁰¹ is an alkylene group which may have a single bond or a substituent, R ²¹ is an alkylene group which may have a single bond or a substituent, and X ⁰² has a substituent. R ²² is an aromatic group which may have a substituent. ]

Wherein (I-1-1) ~ (I -1-5), R 1, Z, Q, p, M + is, ^R 1, Z in formula (I-1), Q, p, M + And the same for each.
In formulas (I-1-1) to (I-1-5), X ⁰¹ represents a single bond or an alkylene group which may have a substituent. As the alkylene group which may have a substituent, the “linear or branched aliphatic hydrocarbon group” in the divalent hydrocarbon group which may have a substituent of X described above, The same thing as "the aliphatic hydrocarbon group which contains a ring in a structure" is mentioned. X ⁰¹ is particularly preferably a single bond or an ethylene group.

In formulas (I-1-1) to (I-1-3), R ²¹ represents a single bond or an alkylene group which may have a substituent. The alkylene group which may have a substituent of R ²¹ is the same as the alkylene group which may have a substituent of R ² in the formula (I-1). R ²¹ is particularly preferably a single bond or a methylene group.

In Formula (I-1-3), ^X02 is an alkylene group which may have a substituent, and may be a divalent which may have a substituent of X in Formula (I-1). Examples of the hydrocarbon group include the same as the “linear or branched aliphatic hydrocarbon group” and the “aliphatic hydrocarbon group containing a ring in the structure”. X ⁰² is particularly preferably an ethylene group.

In formulas (I-1-4) and (I-1-5), R ²² represents an aromatic group that may have a substituent. The aromatic group which may have a substituent of R ^{22 is the same as} the aromatic group which may have a substituent of R ² in the formula (I-1). R ²² is particularly preferably a group obtained by removing one or more hydrogen atoms from a phenyl group or a naphthyl group, or a group obtained by removing two or more hydrogen atoms from quinoline.

In the formula (I-1), M ⁺ is an organic cation.
The organic cation of M ⁺ is not particularly limited. For example, it is conventionally known as a cation moiety such as a photodegradable base used for a quencher of a resist composition or an onium-based acid generator of a resist composition. Organic cations can be used.
As the organic cation of M ⁺ , for example, a cation represented by the following general formula (c-1) or (c-2) can be used.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”は、それぞれ独立に、アリール基またはアルキル基を表し；式（ｃ−１）におけるＲ^１”〜Ｒ^３”のうち、いずれか２つが相互に結合して式中のイオウ原子と共に環を形成してもよい。］

^{Wherein, R 1 "~R 3",} R 5 "~R 6" each independently represents an aryl group or an alkyl group; one of ^R 1 ^{"~R 3"} in the formula (c-1), Any two may be bonded to each other to form a ring together with the sulfur atom in the formula. ]

In formula (c-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group. In addition, any two of R ¹ ″ to R ³ ″ in formula (c-1) may be bonded to each other to form a ring together with the sulfur atom in the formula.
Moreover, it is preferable that at least one of R ¹ ″ to R ³ ″ represents an aryl group. Among R ¹ "~R ^3", more preferably 2 or more is an aryl ^group, all of R 1 "~R ^3" is most preferably an aryl group.

The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and is, for example, an aryl group having 6 to 20 carbon atoms, in which part or all of the hydrogen atoms are alkyl groups, alkoxy groups It may or may not be substituted with a group, a halogen atom, a hydroxyl group or the like.
The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Is most preferred.
As the alkoxy group that may be substituted for the hydrogen atom of the aryl group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, A tert-butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
The halogen atom that may be substituted with the hydrogen atom of the aryl group is preferably a fluorine atom.

The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, linear C1-10, branched or cyclic alkyl group, and the like. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.

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

  Preferable examples of the cation moiety represented by the formula (c-1) include cations represented by the following formulas (c-1-1) to (c-1-32).

In the formulas (c-1-19) and (c-1-20), R ⁵⁰ is a group containing an acid dissociable, dissolution inhibiting group, and the formula (p1), (p1-1) or (p2) described later ) Or an oxygen atom of —R ⁹¹ —C (═O) —O—, the formulas (1-1) to (1-9) or (2-1) to (2- 6) is preferably a bonded group. Here, R ⁹¹ is a single bond or a linear or branched alkylene group, and the alkylene group preferably has 1 to 5 carbon atoms.

  In the formula (c-1-21), W is a divalent linking group, and examples thereof include the same divalent linking groups as X in the formula (I-1). A chain or branched alkylene group, a divalent aliphatic cyclic group, or a divalent linking group containing a hetero atom is preferable, and a linear or branched alkylene group is more preferable. Preferably, it is a linear alkylene group.

In the above formula (c-1-22), R ^f is a fluorinated alkyl group, and is a group in which part or all of the hydrogen atoms of the unsubstituted alkyl group are substituted with fluorine atoms. As this unsubstituted alkyl group, a linear or branched alkyl group is preferable, and a linear alkyl group is more preferable.

In formula (c-1-23), Q is a divalent linking group, and R ⁵¹ is an organic group having a carbonyl group, an ester bond, or a sulfonyl group.
Examples of the divalent linking group for Q include the same as the divalent linking group for X in the formula (I-1), and the divalent linking group includes an alkylene group and an ester bond. Among them, an alkylene group, —R ⁹² —C (═O) —O—R ⁹³ — [R ⁹² , R ⁹³ each independently represents an alkylene group. ] Is more preferable.
R ⁵¹ is an organic group having a carbonyl group, an ester bond, or a sulfonyl group, and the organic group may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group. Examples of the aromatic hydrocarbon group and the aliphatic hydrocarbon group include those similar to X ³ described later. Among them, the organic group having a carbonyl group, an ester bond or a sulfonyl group of R ⁵¹ is preferably an aliphatic hydrocarbon group, more preferably a bulky aliphatic hydrocarbon group, and a cyclic saturated carbonization. More preferably, it is a hydrogen group. R ⁵¹ is preferably a group represented by (L1) to (L6) or (S1) to (S4) described later, a group similar to X ³ described later, a monocyclic group or a polycyclic group. And a group in which the bonded hydrogen atom is substituted with an oxygen atom (═O).

In the formulas (c-1-24) and (c-1-25), R ⁵² is a C 4-10 alkyl group that is not an acid dissociable group. As R ⁵² , a linear or branched alkyl group is preferable, and a linear alkyl group is more preferable.

In the formula (c-1-26), R ⁵³ is a divalent group having a base dissociable site, R ⁵⁴ is a divalent linking group, and R ⁵⁵ is a group having an acid dissociable group. .
Here, the base dissociable part of R ⁵³ refers to a part dissociated by the action of an alkali developer (specifically, a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 ° C.). Dissociation of the base dissociable portion increases solubility in an alkali developer. The alkali developer may be one generally used in the lithography field. The base dissociable portion is preferably dissociated at 23 ° C. by the action of a 2.38 mass% tetramethylammonium hydroxide aqueous solution.
R ⁵³ may be a group composed only of a base dissociable site, or may be a group composed of a base dissociable site and a group or atom that is not dissociated by a base.
As the base dissociable portion of R ⁵³ , an ester bond (—C (═O) —O—) is most preferable.
Examples of the group or atom that R ⁵³ does not dissociate with a base include those similar to the divalent linking group of X in the formula (I-1), and combinations of these linking groups (however, dissociated with a base) Except those that do). Here, the “combination of linking groups” refers to a divalent group formed by bonding of linking groups. Of these, a combination of an alkylene group and a divalent linking group containing a hetero atom is preferable. However, the heteroatom is preferably not adjacent to an atom whose bond is broken by the action of the base in the base dissociable portion.
The alkylene group is the same as the linear or branched alkylene group in the description of X in the formula (I-1).
The heteroatom is particularly preferably an oxygen atom.
Among the above, R ⁵³ is preferably a group composed of a base dissociable portion and a group or atom that is not dissociated by a base.

R ⁵⁴ is a divalent linking group, and examples thereof include the same as the divalent linking group for X in the formula (I-1). Of these, an alkylene group or a divalent aliphatic cyclic group is preferable, and an alkylene group is particularly preferable.
R ⁵⁵ is a group having an acid dissociable group.
Here, the acid dissociable group is an organic group that can be dissociated by the action of an acid, and is not particularly limited as long as it is such as, for example, until now, acid dissociation of a base resin for a chemically amplified resist And those proposed as soluble dissolution inhibiting groups. Specifically, it is the same as the acid dissociable, dissolution inhibiting group described in the structural unit (a1) described later, and is a cyclic or chain tertiary alkyl ester type acid dissociable group; an acetal type acid dissociation such as an alkoxyalkyl group A tertiary alkyl ester type acid dissociable group is preferable among them.
Further, the group having an acid dissociable group may be an acid dissociable group itself, an acid dissociable group, a group or an atom not dissociated by an acid (bonded to an acid generator even after the acid dissociable group is dissociated). Or a group formed by bonding to an as-is group or atom). Here, examples of the group or atom that is not dissociated by an acid include the same groups as the divalent linking group of X in the formula (I-1).

In Formula (c-1-27), W ² is a single bond or a divalent linking group, t is 0 or 1, and R ⁶² is a group that is not dissociated by an acid (hereinafter referred to as “acid non-dissociable group”). It is said.)
Examples of the divalent linking group for W ² include those similar to the divalent linking group for X in the formula (I-1). Among these, W ² is preferably a single bond.
t is preferably 0.
The acid non-dissociable group for R ⁶² is not particularly limited as long as it is a group that does not dissociate by the action of an acid, but is preferably a hydrocarbon group that does not dissociate by an acid and may have a substituent. A cyclic hydrocarbon group which may have a group is more preferable, and a group obtained by removing one hydrogen atom from adamantane is further preferable.

In the above formulas (c-1-28) and (c-1-29), R ⁹ and R ¹⁰ are each independently a phenyl group, naphthyl group or carbon number 1 which may have a substituent. ˜5 alkyl group, alkoxy group and hydroxyl group, u is an integer of 1 to 3, and 1 or 2 is most preferred.

In the formula (c-1-30), Y ¹⁰ represents a cyclic hydrocarbon group having 5 or more carbon atoms which may have a substituent, and represents an acid dissociable group which can be dissociated by the action of an acid. R ⁵⁶ and R ⁵⁷ each independently represent a hydrogen atom, an alkyl group or an aryl group, and R ⁵⁶ and R ⁵⁷ may be bonded to each other to form a ring; Y ¹¹ and Y ¹² are each independently Represents an alkyl group or an aryl group, and Y ¹¹ and Y ¹² may be bonded to each other to form a ring.
Y ¹⁰ represents an acid-dissociable group which is a cyclic hydrocarbon group having 5 or more carbon atoms which may have a substituent and can be dissociated by the action of an acid. Y ¹⁰ is a cyclic hydrocarbon group having 5 or more carbon atoms and is an acid dissociable group that can be dissociated by the action of an acid, so that resolution, LWR, exposure margin (EL margin), resist pattern shape, etc. The lithography properties of the film are good.
Y ¹⁰ includes a group that forms a cyclic tertiary alkyl ester with —C (R ⁵⁶ ) (R ⁵⁷ ) —C (═O) —O—.
The term “tertiary alkyl ester” as used herein refers to a cyclic hydrocarbon group having 5 or more carbon atoms on the terminal oxygen atom of —C (R ⁵⁶ ) (R ⁵⁷ ) —C (═O) —O—. A structure in which a tertiary carbon atom is bonded is shown. In this tertiary alkyl ester, when an acid acts, the bond is broken between the oxygen atom and the tertiary carbon atom.
The cyclic hydrocarbon group may have a substituent, and the carbon atom in the substituent is not included in the carbon number of “5 or more carbon atoms”.

Examples of the “aliphatic cyclic group” include a monocyclic group or a polycyclic group having no aromaticity, and a polycyclic group is preferable.
Such an “aliphatic cyclic group” may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, and an oxygen atom (= O).
Examples of the aliphatic cyclic group include a monocycloalkane which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group; bicycloalkane, tricyclo Examples include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as an alkane or tetracycloalkane. More specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing two or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. .

R ⁵⁶ and R ⁵⁷ each independently represent a hydrogen atom, an alkyl group or an aryl group.
^Examples of the alkyl group or aryl group for R ⁵⁶ and R ⁵⁷ are the same as the alkyl group or aryl group for R ¹ ″ to R ³ ″. Further, R ⁵⁶ and R ⁵⁷ may be bonded to each other to form a ring in the same manner as R ¹ ″ to R ³ ″. Among the above, R ⁵⁶ and R ⁵⁷ are both hydrogen atoms. It is particularly preferred.

Y ¹¹ and Y ¹² each independently represents an alkyl group or an aryl group.
Examples of the alkyl group or aryl group for Y ¹¹ and Y ¹² are the same as the alkyl group or aryl group for R ¹ ″ to R ³ ″.
Among these, Y ¹¹ and Y ¹² are particularly preferably each a phenyl group or a naphthyl group. Y ¹¹ and Y ¹² may be bonded to each other to form a ring in the same manner as R ¹ ″ to R ³ ″.

In the formula (c-1-31), R ⁵⁸ is an aliphatic cyclic group; R ⁵⁹ is a single bond or an alkylene group which may have a substituent; R ⁶⁰ is a substituent. R ⁶¹ is an alkylene group having 4 or 5 carbon atoms which may have a substituent.
The aliphatic cyclic group for R ⁵⁸ may be a monocyclic group or a polycyclic group, but is preferably a polycyclic group, and includes one or more polycycloalkanes. A group in which a hydrogen atom is removed is preferred, and a group in which one or more hydrogen atoms are removed from adamantane is most preferred.
As the alkylene group which may have a substituent of R ^59, a linear or branched alkylene group is preferable, and a single bond or an alkylene group having 1 to 3 carbon atoms is particularly preferable.
The arylene group for R ⁶⁰ preferably has 6 to 20 carbon atoms, more preferably 6 to 14 carbon atoms, and still more preferably 6 to 10 carbon atoms. Examples of such an arylene group include a phenylene group, a biphenylene group, a fluorenylene group, a naphthylene group, an anthrylene group, and a phenanthrylene group, and a phenylene group and a naphthylene group are preferable because they can be synthesized at low cost.

In the formula (c-1-32), R ⁰¹ is an arylene group or an alkylene group, R ⁰² and R ⁰³ are each independently an aryl group or an alkyl group, and R ⁰² and R ⁰³ are bonded to each other. And a sulfur atom in the formula may form a ring, at least one of R ^{01 to} R ⁰³ is an arylene group or an aryl group, W ¹ is an n ″ -valent linking group, and n ″ is 2 or 3.
The arylene group R ^01, not particularly limited, for example, an arylene group having 6 to 20 carbon atoms, said arylene groups, part or all of the hydrogen atoms, those may be substituted The alkylene group represented by R ⁰¹ is not particularly limited, and examples thereof include linear, branched or cyclic alkylene groups having 1 to 10 carbon atoms.
The aryl group for R ⁰² and R ⁰³ is not particularly limited, and may be, for example, an aryl group having 6 to 20 carbon atoms, and the aryl group may have part or all of its hydrogen atoms substituted. There are no particular restrictions on the alkyl group of R ⁰² and R ⁰³ , and examples include linear, branched or cyclic alkyl groups having 1 to 10 carbon atoms.
Examples of the divalent linking group for W ¹ include the same divalent linking groups as those described above for Y ²² , which may be linear, branched or cyclic, and cyclic. preferable. Of these, a group in which two carbonyl groups are combined at both ends of the arylene group is preferable.
The trivalent linking group for W ¹ is preferably a group in which three carbonyl groups are combined with an arylene group.

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

Moreover, as an organic cation of M ^+, the organic cation represented by the following general formula (c-3) is also mentioned.

［式中、Ｒ^４４〜Ｒ^４６はそれぞれ独立してアルキル基、アセチル基、アルコキシ基、カルボキシ基、水酸基またはヒドロキシアルキル基であり；ｎ_７〜ｎ_８はそれぞれ独立して０〜３の整数であり、ｎ_９は０〜２の整数である。］

[Wherein R ^{44 to} R ⁴⁶ are each independently an alkyl group, acetyl group, alkoxy group, carboxy group, hydroxyl group or hydroxyalkyl group; n _{7 to} n ₈ are each independently an integer of 0 to 3; Yes, n ₉ is an integer of 0-2. ]

In R ⁴⁴ to R ^46, the alkyl group is preferably an alkyl group of 1 to 5 carbon atoms, more preferably an linear or branched alkyl group, a methyl group, an ethyl group, a propyl group, an isopropyl radical, n A butyl group or a tert-butyl group is particularly preferable.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, more preferably a linear or branched alkoxy group, and particularly preferably a methoxy group or an ethoxy group.
The hydroxyalkyl group is preferably a group in which one or more hydrogen atoms in the alkyl group are substituted with a hydroxy group, and examples thereof include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.
When the symbols n _{7 to} n ₉ attached to R ^{44 to} R ⁴⁶ are integers of 2 or more, the plurality of R ^{44 to} R ⁴⁶ may be the same or different.
n ₇ is preferably 0 to 2, and more preferably 0 or 1.
n ₈ is preferably 0 or 1, more preferably 0.
n ₉ is preferably 0 or 1, more preferably 1.

<Structural unit (a0)>
The structural unit (a0) is a structural unit containing a —SO ₂ — containing cyclic group.
By using a resist composition containing a polymer having the structural unit (a0), the adhesion of the formed resist film to the substrate is increased. In addition, lithography characteristics such as sensitivity, resolution, exposure margin (EL margin), LWR (line width roughness), LER (line edge roughness), and mask reproducibility are improved.

Here _- as "-SO 2 containing cyclic group", -SO 2 _- within the ring skeleton thereof shows a cyclic group containing a ring containing, in particular, -SO 2 _- in the sulfur atom (S ) Is a cyclic group that forms part of the ring skeleton of the cyclic group.
-SO 2 _- In-containing cyclic group, within the ring skeleton thereof -SO 2 _- in a ring containing as the first ring, when in the case of the ring only having a single cyclic group, yet another ring structure Is referred to as a polycyclic group regardless of its structure.
The —SO ₂ — containing cyclic group may be monocyclic or polycyclic.
The —SO ₂ — containing cyclic group is particularly a cyclic group containing —O—SO ₂ — in the ring skeleton, that is, a ring skeleton in which —O—S— in —O—SO ₂ — is a cyclic group. It is preferable that it is a sultone ring which forms a part of.
The —SO ₂ — containing cyclic group preferably has 3 to 30 carbon atoms, more preferably 4 to 20 carbon atoms, still more preferably 4 to 15 carbon atoms, and particularly preferably 4 to 12 carbon atoms. preferable. However, the carbon number is the number of carbon atoms constituting the ring skeleton, and does not include the carbon number in the substituent.
The —SO ₂ — containing cyclic group may be an —SO ₂ — containing aliphatic cyclic group or an —SO ₂ — containing aromatic cyclic group. Preferably -SO ₂ - containing aliphatic cyclic group.
The —SO ₂ -containing aliphatic cyclic group includes at least a hydrogen atom from an aliphatic hydrocarbon ring in which a part of carbon atoms constituting the ring skeleton is substituted with —SO ₂ — or —O—SO ₂ —. One group is excluded. More specifically, a group obtained by removing at least one hydrogen atom from an aliphatic hydrocarbon ring in which —CH ₂ — constituting the ring skeleton is substituted with —SO ₂ —, —CH ₂ — constituting the ring And a group obtained by removing at least one hydrogen atom from an aliphatic hydrocarbon ring in which CH ₂ — is substituted with —O—SO ₂ —.
The alicyclic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The alicyclic hydrocarbon group may be polycyclic or monocyclic. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms are removed from a monocycloalkane having 3 to 6 carbon atoms. Examples of the monocycloalkane include cyclopentane and cyclohexane. As the polycyclic alicyclic hydrocarbon group, a group in which two hydrogen atoms have been removed from a polycycloalkane having 7 to 12 carbon atoms is preferable. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane. , Tricyclodecane, tetracyclododecane and the like.

The —SO ₂ — containing cyclic group may have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), —COOR ″, —OC (═O) R ″ (R ″ represents a hydrogen atom or an alkyl group). Group), a hydroxyalkyl group, a cyano group, and the like.
The alkyl group as the substituent is preferably an alkyl group having 1 to 6 carbon atoms. The alkyl group is preferably linear or branched. Specific examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a neopentyl group, and a hexyl group. Among these, a methyl group or an ethyl group is preferable, and a methyl group is particularly preferable.
The alkoxy group as the substituent is preferably an alkoxy group having 1 to 6 carbon atoms. The alkoxy group is preferably linear or branched. Specifically, the group couple | bonded with the oxygen atom (-O-) to the alkyl group quoted as the alkyl group as the said substituent is mentioned.
Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group for the substituent include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.
Examples of the halogenated alkyl group as the substituent include a group in which part or all of the hydrogen atoms of the alkyl group mentioned as the alkyl group as the substituent are substituted with the halogen atom. As the halogenated alkyl group, a fluorinated alkyl group is preferable, and a perfluoroalkyl group is particularly preferable.
R ″ in —COOR ″ and —OC (═O) R ″ is preferably a hydrogen atom or a linear, branched or cyclic alkyl group having 1 to 15 carbon atoms.
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and particularly preferably a methyl group or an ethyl group. preferable.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom Alternatively, one or more hydrogen atoms are removed from a polycycloalkane such as a monocycloalkane, bicycloalkane, tricycloalkane, or tetracycloalkane, which may or may not be substituted with a fluorinated alkyl group. More specifically, one or more hydrogen atoms are removed from a monocycloalkane such as cyclopentane or cyclohexane, or a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane or tetracyclododecane. Group.
As the hydroxyalkyl group as the substituent, those having 1 to 6 carbon atoms are preferable. Specifically, at least one hydrogen atom of the alkyl group mentioned as the alkyl group as the substituent is substituted with a hydroxyl group. Group.
More specifically, examples of the —SO ₂ -containing cyclic group include groups represented by the following general formulas (3-1) to (3-4).

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

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

In the general formulas (3-1) to (3-4), A ′ represents an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (—O—) or a sulfur atom (—S—), An oxygen atom or a sulfur atom.
The alkylene group having 1 to 5 carbon atoms in A ′ is preferably a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group.
When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include a group in which —O— or —S— is interposed between the terminal or carbon atoms of the alkylene group, such as —O—CH _{2. -, - CH 2 -O-CH} 2 -, - S-CH 2 -, - CH 2 -S-CH 2 - , and the like.
A ′ is preferably an alkylene group having 1 to 5 carbon atoms or —O—, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.
z may be any of 0 to 2, and is most preferably 0.
When z is 2, the plurality of R ⁶ may be the same or different.
As the alkyl group, alkoxy group, halogenated alkyl group, —COOR ″, —OC (═O) R ″, and hydroxyalkyl group in R ⁶ , the —SO ₂ — containing cyclic group has the above-mentioned, respectively. And the same alkyl groups, alkoxy groups, halogenated alkyl groups, —COOR ″, —OC (═O) R ″, and hydroxyalkyl groups as those which may be substituted.
Below, the specific cyclic group represented by the said general formula (3-1)-(3-4) is illustrated. In the formula, “Ac” represents an acetyl group.

Among the above, the —SO ₂ -containing cyclic group is preferably a group represented by the general formula (3-1), and the chemical formulas (3-1-1), (3-1-18), ( It is more preferable to use at least one selected from the group consisting of groups represented by any of 3-3-1) and (3-4-1), and represented by the chemical formula (3-1-1). Are most preferred.

As the structural unit (a0), a structural unit derived from an acrylate ester in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent is preferable. The explanation of “structural unit derived from acrylate ester” will be described later.
More specifically, examples of the structural unit (a0) include structural units represented by general formula (a0-0) shown below.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、Ｒ^４０は−Ｏ−又は−ＮＨ−であり、Ｒ^３０は−ＳＯ_２−含有環式基であり、Ｒ^２９’は単結合または２価の連結基である。］

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ⁴⁰ represents —O— or —NH—, and R ³⁰ represents —SO ₂ -Containing cyclic group, R ²⁹ 'is a single bond or a divalent linking group. ]

In the formula (a0-0), the alkyl group of R is preferably a linear or branched alkyl group, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, Examples include isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like.
Examples of the halogenated alkyl group for R include groups in which some or all of the hydrogen atoms of the aforementioned R alkyl group have been substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and particularly preferably a hydrogen atom or a methyl group.
In the formula (a0-0), R ⁴⁰ represents —O— or —NH—.
In the formula (a0-0), R ³⁰ is the same as the —SO ₂ -containing cyclic group mentioned above.

In the formula (a0-0), R ²⁹ ′ may be a single bond or a divalent linking group. A divalent linking group is preferred because the lithography properties are further improved.
Preferred examples of the divalent linking group for R ²⁹ ′ include a divalent hydrocarbon group which may have a substituent, a divalent linking group containing a hetero atom, and the like.

(Divalent hydrocarbon group which may have a substituent)
The hydrocarbon group having “substituent” means that part or all of the hydrogen atoms in the hydrocarbon group are substituted with a substituent (a group or atom other than a hydrogen atom).
The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.
An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group as the divalent hydrocarbon group in R ²⁹ ′ may be saturated or unsaturated, and is usually preferably saturated.
More specific examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, and the like.

The linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 6, more preferably 1 to 4, and most preferably 1 to 3.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable, and specific examples thereof include those similar to the linear alkylene group described for X in the formula (I-1). It is done.
The branched aliphatic hydrocarbon group is preferably a branched alkylene group, and specifically, the same as the branched alkylene group described for X in the formula (I-1) can be given. It is done.
The linear or branched aliphatic hydrocarbon group may or may not have a substituent. Examples of the substituent include a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, and an oxygen atom (═O).

  Examples of the aliphatic hydrocarbon group containing a ring in the structure include those similar to the “aliphatic hydrocarbon group containing a ring in the structure” described for X in the formula (I-1). Of these, groups in which two hydrogen atoms have been removed from each of cyclopentane, cyclohexane, adamantane and norbornane are preferred.

The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring.
The aromatic hydrocarbon group as the divalent hydrocarbon group for R ²⁹ ′ preferably has 3 to 30 carbon atoms, more preferably 5 to 30 carbon atoms, still more preferably 5 to 20 carbon atoms, and 6 ~ 15 is particularly preferred, and 6-10 is most preferred. However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic ring of the aromatic hydrocarbon group include aromatic hydrocarbon rings such as benzene, biphenyl, fluorene, naphthalene, anthracene, and phenanthrene; a part of carbon atoms constituting the aromatic hydrocarbon ring is hetero Aromatic heterocycles substituted with atoms; and the like. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom.
Specifically, the aromatic hydrocarbon group is a group obtained by removing two hydrogen atoms from the aromatic hydrocarbon ring (arylene group); a group obtained by removing one hydrogen atom from the aromatic hydrocarbon ring (aryl group) ) In which one of the hydrogen atoms is substituted with an alkylene group (for example, arylalkyl such as benzyl, phenethyl, 1-naphthylmethyl, 2-naphthylmethyl, 1-naphthylethyl, 2-naphthylethyl, etc.) And a group obtained by further removing one hydrogen atom from the aryl group in the group). The alkylene group (alkyl chain in the arylalkyl group) preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.
The aromatic hydrocarbon group may or may not have a substituent. For example, a hydrogen atom bonded to the aromatic hydrocarbon ring of the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.
The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group. Most preferred is an ethoxy group.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

(Divalent linking group containing a hetero atom)
The hetero atom in the “divalent linking group containing a hetero atom” of R ²⁹ ′ is an atom other than a carbon atom and a hydrogen atom, and examples thereof include an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom.
As the divalent linking group containing a hetero atom, —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O—, —C (= O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group, an acyl group, etc.), —S—, —S (═O) ₂ —, —S (═O) _{2 -O -, - NH-C} (= O) -, = N-, the formula ^{-Y 21 -O-Y 22 -,} - [Y 21 -C (= O) -O] m '-Y 22 - Or a group represented by —Y ²¹ —O—C (═O) —Y ²² —, wherein Y ²¹ and Y ²² are each independently a divalent hydrocarbon group optionally having a substituent. O is an oxygen atom, and m ′ is an integer of 0 to 3. ] Etc. are mentioned.
When R ²⁹ ′ is —NH—, H may be substituted with a substituent such as an alkyl group or an aryl group (aromatic group). The substituent (alkyl group, aryl group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 5 carbon atoms.
Formula ^{-Y 21 -O-Y 22 -,} - [Y 21 -C (= O) -O] m '-Y 22 - or ^{-Y 21 -O-C (= O} ) -Y 22 - ^{In, Y 21} And Y ²² are each independently a divalent hydrocarbon group which may have a substituent. Examples of the divalent hydrocarbon group include the same groups as those described above as the “divalent hydrocarbon group optionally having substituent (s)” for R ²⁹ ′.
Y ²¹ is preferably a linear aliphatic hydrocarbon group, more preferably a linear alkylene group, still more preferably a linear alkylene group having 1 to 5 carbon atoms, and particularly preferably a methylene group or an ethylene group. preferable.
Y ²² is preferably a linear or branched aliphatic hydrocarbon group, and more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.
In the group represented by the formula — [Y ²¹ —C (═O) —O] _{m ′} —Y ²² —, m ′ is an integer of 0 to 3, preferably an integer of 0 to 2, Or 1 is more preferable, and 1 is particularly preferable. That is, the group represented by the formula — [Y ²¹ —C (═O) —O] _{m ′} —Y ²² — is represented by the formula —Y ²¹ —C (═O) —O—Y ²² —. The group is particularly preferred. Among these, a group represented by the formula — (CH ₂ ) _{a ′} —C (═O) —O— (CH ₂ ) _{b ′} — is preferable. In the formula, a ′ is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, further preferably 1 or 2, and most preferably 1. b ′ is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, more preferably 1 or 2, and most preferably 1.
Examples of the divalent linking group containing a hetero atom, a linear group containing an oxygen atom as a hetero atom, for example, a group containing an ether bond or an ester bond, are preferred, the formula -Y 21 ^-O-Y 22 ^-, A group represented by — [Y ²¹ —C (═O) —O] _{m ′} —Y ²² — or —Y ²¹ —O—C (═O) —Y ²² — is more preferable.

The divalent linking group for R ²⁹ ′ is preferably an alkylene group, a divalent alicyclic hydrocarbon group, or a divalent linking group containing a hetero atom. Among these, an alkylene group and a divalent linking group containing an ester bond (—C (═O) —O—) are preferable.
The alkylene group is preferably a linear or branched alkylene group.
As the divalent linking group containing an ester bond, in particular, the general formula: —R ²⁰ —C (═O) —O— [wherein R ²⁰ is a divalent linking group. ] Is preferable. That is, the structural unit (a0) is preferably a structural unit represented by the following general formula (a0-0-1).

［式中、Ｒは水素原子、炭素数１〜５のアルキル基又は炭素数１〜５のハロゲン化アルキル基であり、Ｒ^４０は−Ｏ−又は−ＮＨ−であり、Ｒ^２０は２価の連結基であり、Ｒ^３０は−ＳＯ_２−含有環式基である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ⁴⁰ is —O— or —NH—, and R ²⁰ is a divalent group. A linking group, R ³⁰ is a —SO ₂ — containing cyclic group; ]

R ²⁰ is not particularly limited, and examples thereof include those similar to those exemplified as the divalent linking group for R ²⁹ ′ in the general formula (a0-0).
The divalent linking group for R ²⁰ is preferably a linear or branched alkylene group, a divalent alicyclic hydrocarbon group, or a divalent linking group containing a hetero atom.
Examples of the linear or branched alkylene group, divalent alicyclic hydrocarbon group, and divalent linking group containing a hetero atom include the linear groups mentioned above as preferred for R ²⁹ ′. Or the same thing as the branched alkylene group, the bivalent alicyclic hydrocarbon group, and the bivalent coupling group containing a hetero atom is mentioned.
Among these, a linear or branched alkylene group or a divalent linking group containing an oxygen atom as a hetero atom is preferable.
As the linear alkylene group, a methylene group or an ethylene group is preferable, and a methylene group is particularly preferable.
As the branched alkylene group, an alkylmethylene group or an alkylethylene group is preferable, and —CH (CH ₃ ) —, —C (CH ₃ ) ₂ — or —C (CH ₃ ) ₂ CH ₂ — is particularly preferable.
Examples of the divalent linking group containing an oxygen atom, is preferably a divalent linking group containing an ether bond or an ester bond, the formula ^-Y 21 ^{-O-Y 22} -, wherein ^- [Y 21 -C (= O ^{_{) -O] m '- Y 22}} - or the formula ^{-Y 21 -O-C (= O} ) -Y 22 - group represented by is more preferable. Y ²¹ , Y ²² and m ′ are the same as described above.
Among them, a group represented by the formula —Y ²¹ —O—C (═O) —Y ²² — is preferable, and a group represented by the formula — (CH ₂ ) _c —O—C (═O) — (CH ₂ ) _d — The groups represented are particularly preferred. c is an integer of 1 to 5, an integer of 1 to 3 is preferable, and 1 or 2 is more preferable. d is an integer of 1 to 5, an integer of 1 to 3 is preferable, and 1 or 2 is more preferable.

  As the structural unit (a0), a structural unit represented by general formula (a0-0-11) or general formula (a0-0-12) shown below is particularly preferable, and is represented by formula (a0-0-12). The structural unit is more preferable.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基、又は炭素数１〜５のハロゲン化アルキル基であり、Ｒ^４０は−Ｏ−又は−ＮＨ−であり、Ｒ^２０は２価の連結基であり、Ａ’は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり、ｚは０〜２の整数であり、Ｒ^６はアルキル基、アルコキシ基、ハロゲン化アルキル基、水酸基、−ＣＯＯＲ”、−ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基またはシアノ基であり、Ｒ”は水素原子またはアルキル基である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, R ⁴⁰ is —O— or —NH—, and R ²⁰ is divalent. A ′ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, z is an integer of 0 to 2, and R ⁶ is An alkyl group, an alkoxy group, a halogenated alkyl group, a hydroxyl group, —COOR ″, —OC (═O) R ″, a hydroxyalkyl group or a cyano group, and R ″ is a hydrogen atom or an alkyl group.]

In the formulas (a0-0-11) and (a0-0-12), R, R ⁴⁰ , A ′, R ⁶ , z and R ²⁰ are the same as defined above.
In the above formula, A ′ is preferably a methylene group, an ethylene group, an oxygen atom (—O—) or a sulfur atom (—S—).
R ²⁰ is preferably a linear or branched alkylene group or a divalent linking group containing an oxygen atom. As the linear or branched alkylene group and the divalent linking group containing an oxygen atom in R ^20, the linear or branched alkylene group and the divalent linking group containing an oxygen atom respectively mentioned above are used. Examples are the same as the linking group.
As the structural unit represented by the formula (a0-0-12), a structural unit represented by the following general formula (a0-0-12a) or (a0-0-12b) is particularly preferable.

［式中、Ｒ、Ｒ^４０およびＡ’はそれぞれ前記と同じであり、ｃ及びｄはそれぞれ前記と同じであり、ｆは１〜５の整数（好ましくは１〜３の整数）である。］

[Wherein, R, R ⁴⁰ and A ′ are the same as defined above, c and d are the same as defined above, and f is an integer of 1 to 5 (preferably an integer of 1 to 3). ]

The structural unit (a0) contained in the polymer of the present invention may be one type or two or more types.
In the polymer of the present invention, the proportion of the structural unit (a0) is preferably 1 to 60 mol%, more preferably 5 to 55 mol%, based on the total of all the structural units constituting the polymer. 10-50 mol% is more preferable and 15-48 mol% is the most preferable.
By setting the proportion of the structural unit (a0) to the lower limit value or more, the resist pattern shape formed using the resist composition containing the polymer is improved, and lithography characteristics such as EL margin, LWR, mask reproducibility, etc. Even better. On the other hand, by setting it to the upper limit value or less, it becomes easier to balance with other structural units.

<Other structural units>
(Structural unit (a1))
In addition to the structural unit (a0), the polymer of the present invention preferably further includes a structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid.
The “acid-decomposable group” means that at least a part of the bond in the structure of the acid-decomposable group is formed by the action of an acid generated from the anion site at the end of the main chain or the acid generator component (B) described later by exposure. It is a group having acid decomposability that can be cleaved.
Examples of the acid-decomposable group whose polarity increases by the action of an acid include a group that decomposes by the action of an acid to generate a polar group.
Examples of the polar group include a carboxy group, a hydroxyl group, an amino group, a sulfo group (—SO ₃ H), and the like. Among these, a polar group containing —OH in the structure (hereinafter sometimes referred to as “OH-containing polar group”) is preferable, a carboxy group or a hydroxyl group is preferable, and a carboxy group is particularly preferable.
More specifically, examples of the acid-decomposable group include a group in which the polar group is protected with an acid-dissociable group (for example, a group in which a hydrogen atom of an OH-containing polar group is protected with an acid-dissociable group).
The “acid-dissociable group” is at least adjacent to the acid-dissociable group and the acid-dissociable group by the action of an acid generated from the above-mentioned anion site at the end of the main chain or an acid generator component (B) described later upon exposure. It is a group having acid dissociation properties that can cleave the bond with the atom. The acid-dissociable group constituting the acid-decomposable group must be a group having a lower polarity than the polar group generated by dissociation of the acid-dissociable group. Is dissociated, a polar group having a polarity higher than that of the acid dissociable group is generated to increase the polarity. As a result, the polarity of the entire polymer increases. As the polarity increases, the solubility in the developer changes relatively. When the developer is an alkaline developer, the solubility increases. On the other hand, the developer contains an organic solvent (organic type). In the case of a developer, the solubility decreases.

The acid-dissociable group is not particularly limited, and those that have been proposed as acid-dissociable groups for base resins for chemically amplified resists can be used. In general, a group that forms a cyclic or chain tertiary alkyl ester with a carboxy group in (meth) acrylic acid or the like, an acetal type acid dissociable group such as an alkoxyalkyl group, and the like are widely known.
Here, the “tertiary alkyl ester” is an ester formed by replacing a hydrogen atom of a carboxy group with a chain or cyclic alkyl group, and the carbonyloxy group (—C (═O The structure in which the tertiary carbon atom of the chain or cyclic alkyl group is bonded to the terminal oxygen atom of) -O-). In this tertiary alkyl ester, when an acid acts, a bond is cut between an oxygen atom and a tertiary carbon atom to form a carboxy group.
The chain or cyclic alkyl group may have a substituent.
Hereinafter, a group that is acid dissociable by constituting a carboxy group and a tertiary alkyl ester is referred to as a “tertiary alkyl ester type acid dissociable group” for convenience.

Examples of the tertiary alkyl ester type acid dissociable group include an aliphatic branched acid dissociable group and an acid dissociable group containing an aliphatic cyclic group.
Here, “aliphatic branched” means having a branched structure having no aromaticity. The structure of the “aliphatic branched acid dissociable group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
Examples of the aliphatic branched acid dissociable group include a group represented by —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ). ^Wherein, R 71 ^{to R 73} each independently represents a linear alkyl group of 1 to 5 carbon atoms. The group represented by —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ) preferably has 4 to 8 carbon atoms, specifically a tert-butyl group or a 2-methyl-2-butyl group. , 2-methyl-2-pentyl group, 3-methyl-3-pentyl group and the like. A tert-butyl group is particularly preferable.

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The aliphatic cyclic group in the “acid-dissociable group containing an aliphatic cyclic group” may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, and an oxygen atom (= O).
The basic ring structure excluding the substituent of the aliphatic cyclic group is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The hydrocarbon group may be either saturated or unsaturated, but is usually preferably saturated.
The aliphatic cyclic group may be monocyclic or polycyclic.
As the aliphatic cyclic group, those having 3 to 30 carbon atoms are preferable, those having 5 to 30 are more preferable, 5 to 20 are more preferable, 6 to 15 are particularly preferable, and 6 to 12 is most preferable. . As the monocyclic aliphatic cyclic group, a group in which one or more hydrogen atoms have been removed from a monocycloalkane is preferable. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples include cyclobutane, cyclopentane, and cyclohexane. The polycyclic aliphatic cyclic group is preferably a group obtained by removing one or more hydrogen atoms from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane. , Norbornane, isobornane, tricyclodecane, tetracyclododecane and the like. Moreover, a part of carbon atoms constituting the ring of these aliphatic cyclic groups may be substituted with an ether group (—O—).

Examples of the acid dissociable group containing an aliphatic cyclic group include:
(I) a substituent on a carbon atom bonded to an atom (for example, —O— in —C (═O) —O—) adjacent to the acid dissociable group on the ring skeleton of the monovalent aliphatic cyclic group A group in which (atom or group other than hydrogen atom) is bonded to form a tertiary carbon atom;
(Ii) a group having a monovalent aliphatic cyclic group and a branched alkylene having a tertiary carbon atom bonded thereto.
In the group (i), examples of the substituent bonded to the carbon atom bonded to the atom adjacent to the acid dissociable group on the ring skeleton of the aliphatic cyclic group include an alkyl group. Examples of the alkyl group include those similar to R ¹⁴ in formulas (1-1) to (1-9) described later.
Specific examples of the group (i) include groups represented by the following general formulas (1-1) to (1-9).
Specific examples of the group (ii) include groups represented by the following general formulas (2-1) to (2-6).

［式中、Ｒ^１４はアルキル基であり、ｇは０〜８の整数である。］

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

［式中、Ｒ^１５およびＲ^１６は、それぞれ独立してアルキル基である。］

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

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

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

［式中、Ｒ^１’，Ｒ^２’はそれぞれ独立して水素原子または炭素数１〜５のアルキル基を表し、ｎは０〜３の整数を表し、Ｙは炭素数１〜５のアルキル基または脂肪族環式基を表す。］

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

In formula (p1), n is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 0.
Examples of the alkyl group for R ¹ ′ and R ² ′ include the same alkyl groups listed as the substituents that may be bonded to the α-position carbon atom in the description of the α-substituted acrylate ester. A methyl group or an ethyl group is preferred, and a methyl group is most preferred.
In the present invention, it is preferable that at least one of R ¹ ′ and R ² ′ is a hydrogen atom. That is, the acid dissociable group (p1) is preferably a group represented by the following general formula (p1-1).

［式中、Ｒ^１’、ｎ、Ｙは上記と同じである。］

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

Examples of the alkyl group for Y include the same alkyl groups as those described above for the substituent that may be bonded to the carbon atom at the α-position in the description of the α-substituted acrylate ester.
The aliphatic cyclic group for Y can be appropriately selected from monocyclic or polycyclic aliphatic cyclic groups that have been proposed in a number of conventional ArF resists. For example, the above “aliphatic ring” Examples thereof are the same as the aliphatic cyclic groups mentioned in “Acid-dissociable groups containing formula groups”.

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

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

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

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

  In the polymer of the present invention, the structural unit (a1) is a structural unit derived from an acrylate ester in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent, At least a part of the hydrogen atoms in the hydroxyl group of the structural unit (a11) containing an acid-decomposable group whose polarity increases by action and derived from hydroxystyrene or a hydroxystyrene derivative is protected by a substituent containing an acid-decomposable group At least a part of the hydrogen atoms in —C (═O) —OH of the structural unit derived from the structural unit (a12), vinyl benzoic acid or vinyl benzoic acid derivative is protected by a substituent containing an acid-decomposable group. And the structural unit (a13).

Here, in the present specification and claims, the “structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
“Acrylic acid ester” is a compound in which the hydrogen atom at the carboxy group end of acrylic acid (CH ₂ ═CH—COOH) is substituted with an organic group.
In the acrylate ester, the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. The substituent that replaces the hydrogen atom bonded to the α-position carbon atom is an atom or group other than a hydrogen atom, such as an alkyl group having 1 to 5 carbon atoms, a halogenated alkyl group having 1 to 5 carbon atoms, or carbon. Examples thereof include hydroxyalkyl groups of 1 to 5. The α-position carbon atom of the acrylate ester is a carbon atom to which a carbonyl group is bonded unless otherwise specified.
Hereinafter, an acrylate ester in which a hydrogen atom bonded to a carbon atom at the α-position is substituted with a substituent may be referred to as an α-substituted acrylate ester. Further, the acrylate ester and the α-substituted acrylate ester may be collectively referred to as “(α-substituted) acrylate ester”.
In the α-substituted acrylate ester, the alkyl group as a substituent at the α-position is preferably a linear or branched alkyl group, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, n- Examples thereof include a butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, and a neopentyl group.
Specific examples of the halogenated alkyl group as the substituent at the α-position include groups in which part or all of the hydrogen atoms of the above-mentioned “alkyl group as the substituent at the α-position” are substituted with a halogen atom. It is done. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
Specific examples of the hydroxyalkyl group as the substituent at the α-position include groups in which part or all of the hydrogen atoms of the above-mentioned “alkyl group as the substituent at the α-position” are substituted with a hydroxy group. .
Bonded to the α-position of the α-substituted acrylate ester is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, and a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. An alkyl group or a fluorinated alkyl group having 1 to 5 carbon atoms is more preferred, and a hydrogen atom or a methyl group is most preferred from the viewpoint of industrial availability.

“A structural unit derived from hydroxystyrene or a hydroxystyrene derivative” means a structural unit formed by cleavage of an ethylenic double bond of hydroxystyrene or a hydroxystyrene derivative.
“Hydroxystyrene derivative” is a concept including those in which the hydrogen atom at the α-position of hydroxystyrene is substituted with another substituent such as an alkyl group or an alkyl halide group, and derivatives thereof. The α-position (α-position carbon atom) means a carbon atom to which a benzene ring is bonded unless otherwise specified.
The “structural unit derived from vinyl benzoic acid or a vinyl benzoic acid derivative” means a structural unit configured by cleavage of an ethylenic double bond of vinyl benzoic acid or a vinyl benzoic acid derivative.
The “vinyl benzoic acid derivative” is a concept including a compound in which the hydrogen atom at the α-position of vinyl benzoic acid is substituted with another substituent such as an alkyl group or an alkyl halide group, and derivatives thereof. The α-position (α-position carbon atom) means a carbon atom to which a benzene ring is bonded unless otherwise specified.

・ Structural unit (a11)
Specific examples of the structural unit (a11) include structural units represented by general formula (a11-0-1) shown below, structural units represented by general formula (a11-0-2) shown below, and the like. .

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

Wherein R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms; X ¹ is an acid dissociable group; Y ² is a divalent linking group. Yes; X ² is an acid-dissociable group. ]

In the general formula (a11-0-1), the alkyl group and the halogenated alkyl group of R are each exemplified as the substituent which may be bonded to the α-position carbon atom in the description of the α-substituted acrylate ester. And the same alkyl groups and halogenated alkyl groups. R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms, and most preferably a hydrogen atom or a methyl group.
X ¹ is not particularly limited as long as it is an acid dissociable group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable groups, acetal type acid dissociable groups, and the like. An ester type acid dissociable group is preferred.
In general formula (a11-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a11-0-1).

As for the divalent linking group for Y ² , divalent carbonization which may have a substituent, exemplified in the description of the divalent linking group for R ²⁹ ′ in the formula (a0-0). Examples thereof include the same as a hydrogen group and a divalent linking group containing a hetero atom.
Among these, the divalent linking group for Y ² is particularly preferably a linear or branched alkylene group, a divalent alicyclic hydrocarbon group, or a divalent linking group containing a hetero atom. Among these, a linear or branched alkylene group or a divalent linking group containing a hetero atom is preferable.
The divalent linking group containing a hetero atom is preferably a group represented by the formula — (CH ₂ ) _{a ′} —C (═O) —O— (CH ₂ ) _{b ′} —. In the formula, a ′ is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, further preferably 1 or 2, and most preferably 1. b ′ is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, more preferably 1 or 2, and most preferably 1.

  More specifically, examples of the structural unit (a11) include structural units represented by general formulas (a1-1) to (a1-4) shown below.

［式中、Ｒ、Ｒ^１’、Ｒ^２’、ｎ、ＹおよびＹ^２はそれぞれ前記と同じであり、Ｘ’は第３級アルキルエステル型酸解離性基を表す。］’

[Wherein, R, R ¹ ′, R ² ′, n, Y and Y ² are the same as defined above, and X ′ represents a tertiary alkyl ester-type acid dissociable group. ] '

In the formula, X ′ is the same as the tertiary alkyl ester-type acid dissociable group.
^{R 1 ', R 2',} n, as the Y, respectively, ^{R 1} in the general formula listed in the description of "acetal-type acid dissociable group" described above ^{(p1) ', R 2'} , n, similarly to the Y Can be mentioned.
The Y ^2, the same groups as those described above for ^{Y 2} in the above general formula (a11-0-2).
Specific examples of the structural units represented by the general formulas (a1-1) to (a1-4) are shown below.
In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

In the present invention, as the structural unit (a11), a structural unit represented by the following general formula (a11-0-11), a structural unit represented by the following general formula (a11-0-12), and the following general formula ( a11-0-13), a structural unit represented by the following general formula (a11-0-14), a structural unit represented by the following general formula (a11-0-15), and the following general unit It is preferable to have at least one selected from the group consisting of structural units represented by formula (a11-0-2).
Among them, the structural unit represented by the following general formula (a11-0-11), the structural unit represented by the following general formula (a11-0-12), and the following general formula (a11-0-13) A structural unit represented by the following general formula (a11-0-14) and at least one selected from the group consisting of the structural unit represented by the following general formula (a11-0-15) It is more preferable.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、Ｒ^８１はアルキル基であり；Ｒ^８２は、当該Ｒ^８２が結合した炭素原子と共に脂肪族単環式基を形成する基であり；Ｒ^８３は分岐鎖状のアルキル基であり；Ｒ^８４は、当該Ｒ^８４が結合した炭素原子と共に脂肪族多環式基を形成する基であり；Ｒ^８５は炭素数１〜５の直鎖状のアルキル基である。Ｒ^１５およびＲ^１６は、それぞれ独立してアルキル基である。Ｒ^ａ、Ｒ^ｂ及びＲ^ｃは炭素数１〜５のアルキル基である。Ｙ^２は２価の連結基であり、Ｘ^２は酸解離性基である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ⁸¹ is an alkyl group; R ⁸² is a carbon to which R ⁸² is bonded. A group that forms an aliphatic monocyclic group with an atom; R ⁸³ is a branched alkyl group; and R ⁸⁴ is a group that forms an aliphatic polycyclic group together with the carbon atom to which R ⁸⁴ is bonded. R ⁸⁵ is a linear alkyl group having 1 to 5 carbon atoms. R ¹⁵ and R ¹⁶ are each independently an alkyl group. R ^a , R ^b and R ^c are each an alkyl group having 1 to 5 carbon atoms. Y ² is a divalent linking group, and X ² is an acid dissociable group. ]

In each formula, the description of R, Y ² and X ² is the same as described above.
In formula (a11-0-11), examples of the alkyl group for R ⁸¹ include the same alkyl groups as those described above for R ¹⁴ in formulas (1-1) to (1-9). Group or isopropyl group is preferred.
R ⁸² is, the aliphatic monocyclic group formed together with the carbon atom to which R ⁸² is bonded, the same aliphatic cyclic groups as those in the aforementioned tertiary alkyl ester-type acid dissociable groups, a monocyclic group The thing similar to what is is mentioned. Specific examples include groups in which one or more hydrogen atoms have been removed from a monocycloalkane. The monocycloalkane is preferably a 3- to 11-membered ring, more preferably a 3- to 8-membered ring, further preferably a 4- to 6-membered ring, and particularly preferably a 5- or 6-membered ring.
In the monocycloalkane, a part of carbon atoms constituting the ring may or may not be substituted with an ether group (—O—).
Moreover, this monocycloalkane may have a C1-C5 alkyl group, a fluorine atom, or a C1-C5 fluorinated alkyl group as a substituent.
Examples of R ⁸² constituting the aliphatic monocyclic group include a linear alkylene group in which an ether group (—O—) may be interposed between carbon atoms.

Specific examples of the structural unit represented by the formula (a11-0-11) include the formulas (a1-1-16) to (a1-1-23), (a1-1-27), and (a1-1 -31). Among these, the formulas (a1-1-16) to (a1-1-17), (a1-1-20) to (a1-1-23), (a1-1-27), (a1-1-1- The structural unit represented by the following (a11-1-02) including the structural units represented by 31), (a1-1-32), and (a1-1-33) is preferable. Moreover, the structural unit represented by the following (a11-1-02 ′) is also preferable.
In each formula, h is an integer of 1 to 4, and 1 or 2 is preferable.

［式中、Ｒ、Ｒ^８１はそれぞれ前記と同じであり、ｈは１〜４の整数である。］

[Wherein, R and R ⁸¹ are the same as defined above, and h is an integer of 1 to 4. ]

Wherein ^(A11-0-12), as the branched alkyl group ^{R 83,} the alkyl of the formula (1-1) to (1-9) branched chain mentioned by an alkyl group ^{R 14} in Examples thereof are the same as those described above, and an isopropyl group is most preferable.
R ⁸⁴ is, the aliphatic polycyclic group formed together with the carbon atom to which R ⁸⁴ is bonded, the same aliphatic cyclic groups as those in the aforementioned tertiary alkyl ester-type acid dissociable group, polycyclic group The thing similar to what is is mentioned.
Specific examples of the structural unit represented by the formula (a11-0-12) include those represented by the formulas (a1-1-26) and (a1-1-28) to (a1-1-30). Units are listed.
The constitutional unit represented by formula ^{(a11-0-12), R 84} is preferably the aliphatic polycyclic group which forms together with the carbon atom to which ^{R 84} is bonded is a 2-adamantyl group, especially The structural unit represented by the formula (a1-1-26) is preferable.

In formula (a11-0-13), R and R ⁸⁴ are the same as defined above.
As the linear alkyl group for R ^85, the same linear alkyl groups as those described above for the alkyl group for R ¹⁴ in formulas (1-1) to (1-9) can be used, and methyl Most preferred are groups or ethyl groups.
Specific examples of the structural unit represented by the formula (a11-0-13) include formulas (a1-1-1) to (a1-1-2) exemplified as specific examples of the general formula (a1-1). ), Structural units represented by (a1-1-7) to (a1-1-15).
As the structural unit represented by the formula (a11-0-13), those in which R ⁸⁴ is an aliphatic polycyclic group formed together with the carbon atom to which R ⁸⁴ is bonded are preferably a 2-adamantyl group, The structural unit represented by the formula (a1-1-1) or (a1-1-2) is preferable. Further, R ⁸⁴ is also preferably the aliphatic polycyclic group which forms together with the carbon atom to which R ⁸⁴ is bonded is a "group obtained by removing one or more hydrogen atoms from tetracyclododecane", the formula (a1 The structural unit represented by (-1-8), (a1-1-9) or (a1-1-30) is also preferable.

In formula (a11-0-14), R and R ⁸² are the same as defined above. R ¹⁵ and ^{R 16} are the same as ^{R 15} and ^{R 16} in each of the general formulas (2-1) to (2-6).
Specific examples of the structural unit represented by the formula (a11-0-14) include the formulas (a1-1-35) and (a1-1-36) exemplified as specific examples of the general formula (a1-1). ).

In formula (a11-0-15), R and R ⁸⁴ are the same as defined above. R ¹⁵ and ^{R 16} are the same as ^{R 15} and ^{R 16} in each of the general formulas (2-1) to (2-6).
Specific examples of the structural unit represented by the formula (a11-0-15) include formulas (a1-1-4) to (a1-1-6) exemplified as specific examples of the general formula (a1-1). ) And (a1-1-34).

In formula (a11-0-16), R is the same as defined above. R ^a , R ^b and R ^c are each an alkyl group having 1 to 5 carbon atoms, preferably a methyl group or an ethyl group, and particularly preferably all of R ^a , R ^b and R ^c are the same.
Specific examples of the structural unit represented by the formula (a11-0-16) include the formulas (a1-1-24) and (a1-1-25) exemplified as specific examples of the general formula (a1-1). ) And (a1-1-37).

Examples of the structural unit represented by the formula (a11-0-2) include the structural unit represented by the formula (a1-3) or (a1-4), particularly represented by the formula (a1-3). Are preferred.
As the structural unit represented by formula (a11-0-2), particularly, Y ^{2 in} the formula is —Y ²¹ —O—Y ²² — or —Y ²¹ —C (═O) —O—Y ²² —. What is group represented by these is preferable. Y ²¹ and Y ²² are each independently a divalent hydrocarbon group which may have a substituent, and are the same as Y ²¹ and Y ²² described above.
Preferred examples of the structural unit include a structural unit represented by the following general formula (a1-3-01); a structural unit represented by the following general formula (a1-3-02); 3-03) and the like.

［式中、Ｒは前記と同じであり、Ｒ^１３は水素原子またはメチル基であり、Ｒ^１４はアルキル基であり、ｅは１〜１０の整数であり、ｎ’は０〜３の整数である。］

[Wherein, R is the same as above, R ¹³ is a hydrogen atom or a methyl group, R ¹⁴ is an alkyl group, e is an integer of 1 to 10, and n ′ is an integer of 0 to 3] is there. ]

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

[Wherein, R is the same as defined above, Y ² ′ and Y ² ″ are each independently a divalent linking group, X ′ is an acid-dissociable group, and w is an integer of 0 to 3] is there.]

In formulas (a1-3-01) to (a1-3-02), R ¹³ is preferably a hydrogen atom.
R ¹⁴ is the same as ^{R 14} in the formula (1-1) to (1-9).
e is preferably an integer of 1 to 8, more preferably an integer of 1 to 5, and most preferably 1 or 2.
n ′ is preferably 1 or 2, and most preferably 2.
Specific examples of the structural unit represented by the formula (a1-3-01) include structural units represented by the formulas (a1-3-25) to (a1-3-26).
Specific examples of the structural unit represented by the formula (a1-3-02) include structural units represented by the formulas (a1-3-27) to (a1-3-28).

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

［式中、ＲおよびＲ^１４はそれぞれ前記と同じであり、ａ’は１〜１０の整数であり、ｂ’は１〜１０の整数であり、ｔは０〜３の整数である。］

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

In formulas (a1-3-03-1) to (a1-3-03-2), a ′ is the same as described above, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, or 1 or 2 is particularly preferred.
b ′ is the same as described above, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, and particularly preferably 1 or 2.
t is preferably an integer of 1 to 3, and 1 or 2 is particularly preferable.
Specific examples of the structural unit represented by formula (a1-3-03-1) or (a1-3-03-2) include those represented by formulas (a1-3-29) to (a1-3-32). The structural unit represented is mentioned.

  As the structural unit (a11), structural units represented by general formula (a1-5) shown below are also preferred. By having this structural unit, the remaining film ratio and etching resistance in the exposed portion are improved.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基、又は炭素数１〜５のハロゲン化アルキル基であり、ＯＲ^７０は酸分解性基であり、Ｒ^８０は置換基を有していてもよい脂肪族炭化水素基であり、Ｒ^９０は単結合または２価の連結基である。ｍ_１は１〜３の整数であり、ｍ_２は０〜２の整数であり、かつ、ｍ_１＋ｍ_２＝１〜３である。ｍ_４、ｍ_５はそれぞれ独立して０〜３の整数である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, OR ⁷⁰ is an acid-decomposable group, and R ⁸⁰ has a substituent. R ⁹⁰ is a single bond or a divalent linking group. m ₁ is an integer of ₁ to 3, m ₂ is an integer of 0 to 2, and m ₁ + m ₂ = 1 to 3. m ₄ and m ₅ are each independently an integer of 0 to 3. ]

In formula (a1-5), each of the alkyl group and the halogenated alkyl group represented by R is an alkyl group exemplified as the substituent that may be bonded to the carbon atom at the α-position in the description of the α-substituted acrylic ester. And the same as the halogenated alkyl group.
R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a fluorinated alkyl group having 1 to 5 carbon atoms, and most preferably a hydrogen atom or a methyl group.

In formula (a1-5), examples of the acid-decomposable group for OR ⁷⁰ include a group in which a hydrogen atom of an alcoholic hydroxyl group is substituted with an acid-dissociable group.
The “acid-dissociable group” means at least the acid-dissociable group and the acid-dissociated group by the action of an acid (an acid generated from the anion site at the end of the main chain or the acid generator component (B) described later by exposure). It is a group having acid dissociation properties in which a bond between atoms adjacent to the functional group can be cleaved. In the present invention, the acid-dissociable group needs to be a group having a lower hydrophilicity than the alcoholic hydroxyl group generated by dissociation of the acid-dissociable group, whereby the hydrogen atom of the alcoholic hydroxyl group is acid-dissociable. When the acid-dissociable group is dissociated in the group substituted with a group, an alcoholic hydroxyl group is generated (exposed) and hydrophilicity is increased. As a result, the hydrophilicity of the entire polymer is increased, the solubility in the developer is relatively changed, and the solubility is increased when the developer is an alkaline developer, while the developer has an organic solvent. In the case of a developer (organic developer) that contains the solubility, the solubility decreases.
The acid-dissociable group is not particularly limited, and those that have been proposed as acid-dissociable groups in the base resin for chemically amplified resists can be used. For example, the acid-dissociable group is the same as the acid-dissociable group described above. Can be mentioned.
As the acid dissociable group, the tertiary alkyl group-containing acid dissociable group or the acetal type acid is particularly improved because the solubility in an organic solvent (resist solvent), a developing solution and the like when forming a resist composition is further improved. A dissociable group is preferred.

(Tertiary alkyl group-containing acid dissociable group)
“Tertiary alkyl group” refers to an alkyl group having a tertiary carbon atom. “Alkyl group” refers to a monovalent saturated hydrocarbon group, and includes a chain (straight chain or branched chain) alkyl group and an alkyl group having a cyclic structure.
The “tertiary alkyl group-containing acid dissociable group” refers to an acid dissociable group containing a tertiary alkyl group in its structure. The tertiary alkyl group-containing acid dissociable group may be composed only of a tertiary alkyl group, and is composed of a tertiary alkyl group and another atom or group other than the tertiary alkyl group. May be.
Examples of the “other atom or group other than the tertiary alkyl group” that constitutes the tertiary alkyl group-containing group together with the tertiary alkyl group include, for example, a carbonyloxy group, a carbonyl group, an alkylene group, an oxygen atom (—O -) Etc. are mentioned.

Examples of the tertiary alkyl group-containing acid dissociable group include a tertiary alkyl group-containing acid dissociable group having no cyclic structure and a tertiary alkyl group-containing acid dissociable group having a cyclic structure.
The “tertiary alkyl group-containing acid dissociable group having no cyclic structure” contains a branched tertiary alkyl group as the tertiary alkyl group, and has a cyclic structure in the structure. There are no acid dissociable groups.
Examples of the branched tertiary alkyl group include groups represented by the following general formula (I).

In formula (I), R ^{23 to} R ²⁵ are each independently a linear or branched alkyl group. 1-5 are preferable and, as for carbon number of this alkyl group, 1-3 are more preferable.
Moreover, it is preferable that the total carbon number of group represented by general formula (I) is 4-7, it is more preferable that it is 4-6, and it is most preferable that it is 4-5.
Preferred examples of the group represented by the general formula (I) include a tert-butyl group and a tert-pentyl group, and a tert-butyl group is more preferable.

  The tertiary alkyl group-containing acid dissociable group having no cyclic structure includes the above-described branched tertiary alkyl group; the branched tertiary alkyl group is linear or branched A tertiary alkyl group-containing chain alkyl group bonded to an alkylene group; a tertiary alkyloxycarbonyl group having the branched tertiary alkyl group as a tertiary alkyl group; a tertiary alkyl group And tertiary alkyloxycarbonylalkyl groups having a branched tertiary alkyl group.

The alkylene group in the tertiary alkyl group-containing chain alkyl group is preferably an alkylene group having 1 to 5 carbon atoms, more preferably an alkylene group having 1 to 4 carbon atoms, and still more preferably an alkylene group having 2 to 2 carbon atoms.
Examples of the chain-like tertiary alkyloxycarbonyl group include a group represented by the following general formula (II).
^R 23 ^{to R 25} in the formula (II) is the same as ^R 23 ^{to R 25} in general formula (I).
The chain-like tertiary alkyloxycarbonyl group is preferably a tert-butyloxycarbonyl group (t-boc) or a tert-pentyloxycarbonyl group.

Examples of the chain-like tertiary alkyloxycarbonylalkyl group include a group represented by any one of the following general formula (III-1) and general formula (III-2).
Formula ^{(III-1), R 23} ~R 25 in (III-2) is the same as ^R 23 ^{to R 25} in general formula (I).
m ₆ is an integer of 1 to 3, and 1 or 2 is preferable.
R ³ ′ represents an alkyl group having 1 to 5 carbon atoms, preferably a methyl group or an ethyl group, and most preferably a methyl group.
As the chain-like tertiary alkyloxycarbonylalkyl group, a tert-butyloxycarbonylmethyl group and a tert-butyloxycarbonylethyl group are preferable.

  Among the above, as the tertiary alkyl group-containing acid dissociable group having no cyclic structure, a tertiary alkyloxycarbonyl group or a tertiary alkyloxycarbonylalkyl group is an organic developer before and after exposure. From the viewpoint of contrast with respect to, a tertiary alkyloxycarbonyl group is more preferable, and a tert-butyloxycarbonyl group (t-boc) is most preferable.

The “tertiary alkyl group-containing acid dissociable group having a cyclic structure” is an acid dissociable group having a tertiary carbon atom and a cyclic structure in its structure.
In the tertiary alkyl group-containing acid dissociable group having a cyclic structure, the cyclic structure preferably has 4 to 12 carbon atoms, more preferably 5 to 10 carbon atoms, and more preferably 6 to 10 carbon atoms. Most preferably it is.
As the cyclic structure, an aliphatic cyclic group is preferable. The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The aliphatic cyclic group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like. Is mentioned.
The basic ring structure excluding the substituent of the aliphatic cyclic group is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The hydrocarbon group may be either saturated or unsaturated, but is usually preferably saturated.
The aliphatic cyclic group may be monocyclic or polycyclic.
Examples of the aliphatic cyclic group include one or more hydrogens from a monocycloalkane which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group. Examples thereof include a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, and tetracycloalkane. More specifically, a group obtained by removing one or more hydrogen atoms from a monocycloalkane such as cyclopentane or cyclohexane, or one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. And alicyclic hydrocarbon groups such as a group in which a hydrogen atom is removed. Moreover, a part of carbon atoms constituting the ring of these alicyclic hydrocarbon groups may be substituted with an ether group (—O—).

Examples of the tertiary alkyl group of the tertiary alkyl group-containing acid dissociable group having a cyclic structure include the following groups [1] and [2].
[1] A tertiary carbon atom is formed by bonding an alkyl group to a carbon atom bonded to an atom adjacent to the tertiary alkyl group on the ring skeleton of a monovalent aliphatic cyclic group. A secondary alkyl group.
[2] It has a monovalent aliphatic cyclic group and an alkylene group having a tertiary carbon atom (branched alkylene group), and the tertiary carbon atom is adjacent to the tertiary alkyl group A tertiary alkyl group bonded to an atom.
In the group [1] or [2], examples of the monovalent aliphatic cyclic group include the same aliphatic cyclic groups as those described in the description of the cyclic structure.

In the group [1], the alkyl group bonded to the aliphatic cyclic group may be linear, branched or cyclic, and is preferably linear or branched.
The linear alkyl group preferably has 1 to 5 carbon atoms, more preferably 1 to 4, and still more preferably 1 or 2. Specific examples include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, and an n-pentyl group. Among these, a methyl group, an ethyl group, or an n-butyl group is preferable, and a methyl group or an ethyl group is more preferable.
The branched alkyl group preferably has 3 to 10 carbon atoms, and more preferably 3 to 5 carbon atoms. Specific examples include isopropyl group, isobutyl group, tert-butyl group, isopentyl group, neopentyl group and the like, and isopropyl group is most preferable.
Specific examples of the group [1] include groups represented by the general formulas (1-1) to (1-9) described above.
Specific examples of the group [2] include groups represented by the general formulas (2-1) to (2-6) described above.

As the tertiary alkyl group-containing acid dissociable group having a cyclic structure, for example, a tertiary alkyl group having a cyclic structure; a tertiary alkyl group having a tertiary alkyl group having the cyclic structure as a tertiary alkyl group can be used. Alkyloxycarbonyl group; a tertiary alkyloxycarbonylalkyl group having a tertiary alkyl group having the cyclic structure as the tertiary alkyl group.
Examples of the tertiary alkyl group having a cyclic structure include the above-described group [1] or [2].
Specifically, as the tertiary alkyloxycarbonyl group, the —C (R ²³ ) (R ²⁴ ) (R ²⁵ ) moiety in the general formula (II) is substituted with a tertiary alkyl group having a cyclic structure. Group.
Specifically, as the tertiary alkyloxycarbonylalkyl group, the —C (R ²³ ) (R ²⁴ ) (R ²⁵ ) moiety in the general formulas (III-1) and (III-2) is cyclic. And a group substituted with a tertiary alkyl group having a structure.

As the tertiary alkyl group-containing acid dissociable group, among the above, a group represented by the general formula (II) (particularly preferably a tert-butyloxycarbonyl group (t-boc)); A group in which the —C (R ²³ ) (R ²⁴ ) (R ²⁵ ) moiety in III-2) is substituted with a tertiary alkyl group having a cyclic structure is preferred.

(Acetal type acid dissociable group)
When an acid is generated upon exposure to an acetal acid dissociable group, this acid acts to break the bond between the acetal acid dissociable group and the oxygen atom to which the acetal acid dissociable group is bonded. The
Examples of the acetal type acid dissociable group include those similar to the above-mentioned “acetal type acid dissociable group”.
In the structural unit represented by the formula (a1-5), preferred specific examples of —OR ⁷⁰ (when R ⁷⁰ is an acetal type acid dissociable group) include a methoxymethoxy group, an ethoxymethoxy group, and n-butoxymethoxy. Group, cyclohexyloxymethoxy group, adamantyloxymethoxy group, 1-ethoxyethoxy group, 1-n-butoxyethoxy group, 1-cyclohexyloxyethoxy group, 1-adamantyloxyethoxy group and the like.

In the formula (a1-5), R ⁸⁰ represents an aliphatic hydrocarbon group which may have a substituent.
An aliphatic hydrocarbon group means a hydrocarbon group having no aromaticity.
The aliphatic hydrocarbon group for R ⁸⁰ may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic.
The aliphatic hydrocarbon group “may have a substituent” means that a part of carbon atoms constituting the aliphatic hydrocarbon group may be substituted with a substituent containing a hetero atom, It means that part or all of the hydrogen atoms constituting the aliphatic hydrocarbon group may be substituted with a substituent containing a hetero atom.
The “heteroatom” in R ⁸⁰ is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom.
The substituent containing a hetero atom may consist of only the hetero atom, or may be a group containing the hetero atom and a group or atom other than the hetero atom. Specifically, for example, —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O—, —C (═O) —NH—, -NH- (H is an alkyl group, may be substituted with a substituent such as an acyl _{group), - S -, - S} (= O) 2 -, - S (= O) 2 -O- and the like can be mentioned It is done. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent for substituting part or all of the hydrogen atoms constituting the aliphatic hydrocarbon group include, for example, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (= O), cyano Group, alkyl group and the like.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.
As said alkyl group, a C1-C5 alkyl group (lower alkyl group), for example, a methyl group, an ethyl group, a propyl group, n-butyl group, a tert-butyl group etc. are mentioned.

When ^R80 is a linear or branched aliphatic hydrocarbon group, the carbon number is preferably 1 to 10, more preferably 1 to 5, and most preferably 1 to 3. Specifically, a chain alkylene group is preferable.

When R ⁸⁰ is a cyclic aliphatic hydrocarbon group (aliphatic cyclic group), the structure of the basic ring (aliphatic ring) excluding the substituent of the aliphatic cyclic group is a ring composed of carbon and hydrogen. It is not limited to being a (hydrocarbon ring), and a hetero atom such as an oxygen atom may be included in the structure of the ring (aliphatic ring). The “hydrocarbon ring” may be either saturated or unsaturated, but is usually preferably saturated.
The aliphatic cyclic group may be either a polycyclic group or a monocyclic group. Examples of the aliphatic cyclic group include a monocycloalkane which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group; a bicycloalkane, a tricycloalkane, or a tetracycloalkane. Groups obtained by removing two or more hydrogen atoms from polycycloalkanes and the like. More specifically, monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing two or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane are listed. .
Examples of the aliphatic cyclic group include two or more hydrogen atoms from tetrahydrofuran or tetrahydropyran which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group. Examples include groups other than.
In the structural unit represented by the formula (a1-5), the aliphatic cyclic group is preferably a polycyclic group, and particularly preferably a group obtained by removing two or more hydrogen atoms from adamantane.

In formula (a1-5), the divalent linking group for R ⁹⁰ is not particularly limited, but may be a divalent hydrocarbon group which may have a substituent, or a divalent linking group containing a hetero atom. Etc. are mentioned as suitable.
The divalent hydrocarbon group which may have a substituent for R ^{90 and} the divalent linking group containing a hetero atom are the same as those of the divalent linking group for R ²⁹ ′ in formula (a0-0). The same thing as the bivalent hydrocarbon group which may have a substituent illustrated in description, the bivalent coupling group containing a hetero atom, etc. are mentioned.
Among these, the divalent linking group for R ⁹⁰ is particularly preferably a linear or branched alkylene group, a divalent alicyclic hydrocarbon group, or a divalent linking group containing a hetero atom. Among these, a linear or branched alkylene group or a divalent linking group containing a hetero atom is preferable.
Examples of the divalent linking group containing a hetero atom, a linear group containing an oxygen atom as a hetero atom, for example, a group containing an ether bond or an ester bond preferably, the formula ^{-Y 21 -O-Y 22 -,} - [ Y ²¹ —C (═O) —O] is more preferably a group represented by _{m ′} —Y ²² — or —Y ²¹ —O—C (═O) —Y ²² —. Y ²¹ and Y ²² are each independently a divalent hydrocarbon group which may have a substituent, and are the same as Y ²¹ and Y ²² described above. m 'is an integer of 0-3.

In the formula (a1-5), _{m 1} is an integer of 1 to 3, _{m 2} is an integer of 0 to 2, and _a m ₁ + m 2 = 1~3.
m ₁ is preferably 1 or 2.
m ₂ is preferably 0.
m ₁ + m ₂ is preferably 1 or 2.
m ₄ is an integer of 0 to 3, preferably 0 or 1, and more preferably 0.
m ₅ is an integer of 0 to 3, preferably 0 or 1, and more preferably 0.

Among the above, it is preferable that R ⁹⁰ in the formula (a1-5) is a single bond or a linear alkylene group having 1 to 3 carbon atoms. That is, the structural unit represented by the following general formula (a1-51) is preferable.
Especially, the structural unit represented by the following general formula (a1-511), (a1-512), or (a1-513) is preferable.

［式（ａ１−５１）中、Ｒ、ＯＲ^７０、Ｒ^８０、ｍ_１、ｍ_２、ｍ_４、ｍ_５はそれぞれ前記と同じであり、ｍ_３は０〜３の整数である。］

[In the formula (a1-51), R, OR ⁷⁰ , R ⁸⁰ , m ₁ , m ₂ , m ₄ and m ₅ are the same as defined above, and m ₃ is an integer of 0 to 3. ]

［式中、Ｒ，ＯＲ^７０，ｍ_２，ｍ_３，ｍ_４，ｍ_５はそれぞれ前記と同じである。］

[Wherein, R, OR ⁷⁰ , m ₂ , m ₃ , m ₄ and m ₅ are the same as defined above. ]

［式中、Ｒ，ＯＲ^７０，ｍ_２，ｍ_３，ｍ_４，ｍ_５はそれぞれ前記と同じである。］

[Wherein, R, OR ⁷⁰ , m ₂ , m ₃ , m ₄ and m ₅ are the same as defined above. ]

［式中、Ｒ，ＯＲ^７０，ｍ_１，ｍ_２，ｍ_３，ｍ_４，ｍ_５はそれぞれ前記と同じである。ｃ”は１〜３の整数である。］

[Wherein, R, OR ⁷⁰ , m ₁ , m ₂ , m ₃ , m ₄ , m ₅ are the same as defined above. c ″ is an integer of 1 to 3.]

In formula (a1-51), m ₃ is an integer of 0 to 3, preferably 0 or 1, and more preferably 0.
In formula (a1-513), c ″ is an integer of 1 to 3, preferably 1 or 2, and more preferably 1.
When m ₃ in the formula (a1-513) is 0, the oxygen atom at the terminal of the carbonyloxy group (—C (═O) —O—) of the acrylate ester is bonded to the oxygen atom in the cyclic group. It is preferably not bonded to a carbon atom. That is, when m ₃ is 0, there are two or more carbon atoms between the terminal oxygen atom and the oxygen atom in the cyclic group (the number of carbon atoms is 1 (that is, an acetal bond It is preferable that the above is excluded).

Specific examples of the structural unit represented by the general formula (a1-5) are shown below.
In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

Structural unit (a12), structural unit (a13)
In the present specification, the structural unit (a12) is a structural unit in which at least a part of hydrogen atoms in the phenolic hydroxyl group of the structural unit derived from hydroxystyrene or a hydroxystyrene derivative is protected by a substituent containing an acid-decomposable group. It is.
In addition, the structural unit (a13) is protected by a substituent in which at least a part of the hydrogen atoms in —C (═O) —OH of the structural unit derived from vinylbenzoic acid or a vinylbenzoic acid derivative contains an acid-decomposable group. Unit.
In the structural unit (a12) and the structural unit (a13), examples of the substituent containing an acid-decomposable group include the tertiary alkyl ester type acid dissociable group and the acetal type acid dissociable group described in the structural unit (a11). Is preferable.

When the polymer of this invention has a structural unit (a1), the said structural unit (a1) may be 1 type, and 2 or more types may be sufficient as it.
Among these, the structural unit (a1) is preferably a structural unit (a11) derived from an acrylate ester in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent. .
In the polymer of the present invention, the proportion of the structural unit (a1) is preferably from 15 to 70 mol%, more preferably from 15 to 60 mol%, more preferably from 20 to 55 mol%, based on all the structural units constituting the polymer. Is more preferable.
By setting the proportion of the structural unit (a1) to the lower limit value or more, a pattern can be easily obtained when a resist composition is formed, and the lithography properties such as sensitivity, resolution, and LWR are also improved. Moreover, it becomes easy to balance with another structural unit by setting it as an upper limit or less.

When the polymer of the present invention contains two or more structural units (a1), it is preferably a combination of two or more structural units having the tertiary alkyl ester type acid dissociable group,
A combination of two or more structural units having a “group having a tertiary carbon atom on the ring skeleton of a cyclic alkyl group” is more preferable. Among the,
A combination of a monocyclic ring skeleton of a structural unit having a “group having a tertiary carbon atom on the ring skeleton of a cyclic alkyl group” and a polycyclic ring skeleton is particularly preferred.
Specific examples thereof include a combination of the structural unit represented by the general formula (a11-0-11) and the structural unit represented by the general formula (a11-0-12).

The polymer of this invention may have other structural units other than said structural unit (a0) and structural unit (a1) according to a use within the range which does not impair the effect of this invention.
Such other structural unit is not particularly limited as long as it is a structural unit that is not classified as the above-mentioned structural unit, and it is used for resist resins such as for ArF excimer laser and for KrF excimer laser (preferably for ArF excimer laser). Many things conventionally known as what is used can be used.
Such other structural units include:
a structural unit derived from an acrylate ester in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent, and a structural unit (a2) including a lactone-containing cyclic group,
a structural unit derived from an acrylate ester optionally substituted with a hydrogen atom bonded to the α-position carbon atom and comprising a polar group-containing aliphatic hydrocarbon group (a3),
A structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, and comprising a non-acid-dissociable aliphatic polycyclic group (a4) Etc.

(Structural unit (a2))
The structural unit (a2) is a structural unit derived from an acrylate ester in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent, and includes a lactone-containing cyclic group. .
Here, the lactone-containing cyclic group refers to a cyclic group containing a ring (lactone ring) containing —O—C (═O) — in the ring skeleton. The lactone ring is counted as the first ring. When only the lactone ring is present, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of the structure. The lactone-containing cyclic group may be a monocyclic group or a polycyclic group.
The lactone cyclic group in the structural unit (a2) is not particularly limited, and any one can be used. Specifically, as the lactone-containing monocyclic group, a group in which one hydrogen atom is removed from a 4- to 6-membered ring lactone, for example, a group in which one hydrogen atom is removed from β-propionolactone, or γ-butyrolactone. Examples thereof include a group in which one hydrogen atom has been removed and a group in which one hydrogen atom has been removed from δ-valerolactone. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.
Examples of the structural unit (a2) include those in which R ²⁸ in the general formula (a2-0) is substituted with a lactone-containing cyclic group, and more specifically, the following general formula (a2-1) ) To (a2-5).

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

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

R in the general formulas (a2-1) to (a2-5) is the same as described above.
Examples of the alkyl group having 1 to 5 carbon atoms of R ′ include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group.
Examples of the alkoxy group having 1 to 5 carbon atoms of R ′ include a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, and a tert-butoxy group.
R ′ is preferably a hydrogen atom in view of industrial availability.
The alkyl group in R ″ may be linear, branched or cyclic.
When R ″ is a linear or branched alkyl group, it preferably has 1 to 10 carbon atoms, and more preferably 1 to 5 carbon atoms.
When R ″ is a cyclic alkyl group, it preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, a fluorine atom Or a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorinated alkyl group Specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane, or a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Etc.
Examples of A ″ include the same as A ′ in the general formula (3-1). A ″ represents an alkylene group having 1 to 5 carbon atoms, an oxygen atom (—O—) or a sulfur atom (— S-) is preferable, and an alkylene group having 1 to 5 carbon atoms or -O- is more preferable. The alkylene group having 1 to 5 carbon atoms is more preferably a methylene group or dimethylmethylene group, and most preferably a methylene group.
R ²⁹ is the same as ^{R 29} in the aforementioned general formula (a2-0).
In formula (a2-1), s ″ is preferably 1 to 2.
Specific examples of the structural units represented by the general formulas (a2-1) to (a2-5) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

As the structural unit (a2), at least one selected from the group consisting of structural units represented by the general formulas (a2-1) to (a2-5) is preferable, and the general formulas (a2-1) to ( More preferably, at least one selected from the group consisting of structural units represented by a2-3) is selected from the group consisting of structural units represented by the general formula (a2-1) or (a2-3). At least one of these is particularly preferred.
Among them, the formulas (a2-1-1), (a2-1-2), (a2-2-1), (a2-2-7), (a2-2-12), (a2-2-2-) 14), (a2-3-1), at least one selected from the group consisting of structural units represented by (a2-3-5) is preferred.

  Moreover, as the structural unit (a2), structural units represented by the following formulas (a2-6) to (a2-7) are also preferable.

［式中、Ｒ、Ｒ^２９は前記同様である。］

[Wherein, R and R ²⁹ are the same as defined above. ]

When the polymer of this invention has a structural unit (a2), the said structural unit (a2) may be 1 type, and 2 or more types may be sufficient as it.
In the polymer of the present invention, the proportion of the structural unit (a2) is preferably 1 to 80 mol%, and preferably 10 to 70 mol%, based on the total of all the structural units constituting the polymer. More preferably, it is more preferably 10 to 65 mol%, particularly preferably 10 to 60 mol%.
By setting it to the lower limit value or more, the effect of containing the structural unit (a2) can be sufficiently obtained, and by setting it to the upper limit value or less, it is possible to balance with other structural units, such as various kinds of DOF, CDU, etc. The lithography characteristics and pattern shape of the film are improved.

(Structural unit (a3))
The structural unit (a3) is a structural unit derived from an acrylate ester in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent, and includes a polar group-containing aliphatic hydrocarbon group Unit (however, the units corresponding to the structural units (a0), (a1), and (a2) described above are excluded).
By using a resist composition containing a polymer having the structural unit (a3), the hydrophilicity of the polymer is increased and the resolution is further improved.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom. A hydroxyl group is particularly preferable.
Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) and a cyclic aliphatic hydrocarbon group (cyclic group). The cyclic group may be a monocyclic group or a polycyclic group. For example, a resin for a resist composition for an ArF excimer laser can be appropriately selected from those proposed. The cyclic group is preferably a polycyclic group, and more preferably 7 to 30 carbon atoms.
Among them, a structural unit derived from an acrylate ester containing an aliphatic polycyclic group containing a hydroxyalkyl group in which a part of hydrogen atoms of a hydroxyl group, a cyano group, a carboxy group, or an alkyl group is substituted with a fluorine atom Is more preferable. Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like. Specific examples include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, there are groups in which two or more hydrogen atoms have been removed from adamantane, groups in which two or more hydrogen atoms have been removed from norbornane, and groups in which two or more hydrogen atoms have been removed from tetracyclododecane. Industrially preferable.

  The structural unit (a3) is derived from a hydroxyethyl ester of acrylic acid when the hydrocarbon group in the polar group-containing aliphatic hydrocarbon group is a linear or branched hydrocarbon group having 1 to 10 carbon atoms. When the hydrocarbon group is a polycyclic group, the structural unit represented by the following formula (a3-1), the structural unit represented by the formula (a3-2), the formula ( The structural unit represented by a3-3) is preferred.

（式中、Ｒは前記と同じであり、ｊは１〜３の整数であり、ｋは１〜３の整数であり、ｔ’は１〜３の整数であり、ｌは１〜５の整数であり、ｓは１〜３の整数である。）

(Wherein R is the same as above, j is an integer of 1 to 3, k is an integer of 1 to 3, t 'is an integer of 1 to 3, and l is an integer of 1 to 5) And s is an integer of 1 to 3.)

In formula (a3-1), j is preferably 1 or 2, and more preferably 1. When j is 2, it is preferable that the hydroxyl group is bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group.
j is preferably 1, and it is particularly preferred that the hydroxyl group is bonded to the 3-position of the adamantyl group.

  In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5th or 6th position of the norbornyl group.

  In formula (a3-3), t ′ is preferably 1. l is preferably 1. s is preferably 1. In these, a 2-norbornyl group or a 3-norbornyl group is preferably bonded to the terminal of the carboxy group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.

When the polymer of this invention has a structural unit (a3), the said structural unit (a3) may be 1 type, and 2 or more types may be sufficient as it.
In the polymer of the present invention, the proportion of the structural unit (a3) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, based on the total of all the structural units constituting the polymer. 5-25 mol% is more preferable.
By setting the proportion of the structural unit (a3) to the lower limit value or more, the effect of including the structural unit (a3) can be sufficiently obtained, and by setting the proportion of the structural unit (a3) to the upper limit value or less, balance with other structural units can be obtained. It becomes easy.

(Structural unit (a4))
The structural unit (a4) is a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, and is a non-acid-dissociable aliphatic polycyclic group Is a structural unit including
In the structural unit (a4), examples of the polycyclic group include the same polycyclic groups as exemplified in the case of the structural unit (a1). For ArF excimer laser, KrF excimer Many things conventionally known as what is used for the resin component of resist compositions, such as for lasers (preferably for ArF excimer lasers), can be used.
In particular, at least one selected from a tricyclodecyl group, an adamantyl group, a tetracyclododecyl group, an isobornyl group, and a norbornyl group is preferable in terms of industrial availability. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
Specific examples of the structural unit (a4) include those represented by the following general formulas (a4-1) to (a4-5).

（式中、Ｒは前記のものと同じ意味である。）

(Wherein R has the same meaning as described above.)

When the polymer of this invention has a structural unit (a4), the said structural unit (a4) may be used individually by 1 type, and may be used in combination of 2 or more type.
When such a structural unit (a4) is contained in the polymer of the present invention, it is preferable to contain 1-30 mol% of the structural unit (a4) with respect to the total of all the structural units constituting the polymer. 10 to 20 mol% is more preferable.

The polymer of the present invention has the anion moiety described above at least at one end of the main chain, and has the structural unit (a0), and further preferably has the structural unit (a1). .
As such a polymer, the main chain is composed of a repeating structure of the structural unit (a0) and the structural unit (a1), and the main chain is composed of the structural unit (a0), the structural unit (a1) and the structural unit (a3). And those having a repeating structure of the structural unit (a0), the structural unit (a1), the structural unit (a2), and the structural unit (a3) can be exemplified as preferable examples. .
More specifically, such a polymer has a group represented by the general formula (I-1-1) at the end of the main chain, and is represented by the general formula (a0-0-12). And a group represented by the general formula (a11-0-11); a group represented by the general formula (I-1-1) at the end of the main chain; and A structural unit represented by the general formula (a0-0-12), a structural unit represented by the general formula (a11-0-13), and a structural unit represented by the general formula (a3-1), A structural unit having the group represented by the general formula (I-1-1) at the end of the main chain and represented by the general formula (a0-0-12) and the general formula Having the structural unit represented by (a1-2) and the structural unit represented by the general formula (a3-1); at the end of the main chain, the general formula (I-1- ) And a structural unit represented by the general formula (a0-0-12), a structural unit represented by the general formula (a11-0-12), and the general formula ( having the structural unit represented by a3-1); having a group represented by the general formula (I-1-1) at the end of the main chain, and the general formula (a0-0-12) ), A structural unit represented by the general formula (a1-3-03), and a structural unit represented by the general formula (a3-1); It has a group represented by the general formula (I-1-1) and is represented by the structural unit represented by the general formula (a0-0-12) and the general formula (a11-0-11). Having a group represented by the general formula (I-1-1) at the end of the main chain. And a structural unit represented by the general formula (a0-0-12), a structural unit represented by the general formula (a11-0-15), and a structure represented by the general formula (a3-1). A unit having a group represented by the general formula (I-1-1) at the end of the main chain, and the structural unit represented by the general formula (a0-0-12) Having a structural unit represented by the general formula (a11-0-16) and a structural unit represented by the general formula (a3-1); and at the end of the main chain, the general formula (I-1-1) A structural unit represented by the general formula (a0-0-12), a structural unit represented by the general formula (a11-0-11), and the general formula (a1). -2) and the structural unit represented by the general formula (a3-1); the general formula (I-1) at the end of the main chain -1) and a structural unit represented by the general formula (a0-0-11), a structural unit represented by the general formula (a1-2), and the general formula ( having the structural unit represented by a3-1); having a group represented by the general formula (I-1-1) at the end of the main chain, and the general formula (a0-0-12) ), A structural unit represented by the general formula (a1-2), a structural unit represented by the general formula (a11-0-12), and the general formula (a3-1). Having a group represented by the general formula (I-1-1) at the end of the main chain, and a structure represented by the general formula (a0-0-12) Unit, structural unit represented by general formula (a2-1), structural unit represented by general formula (a11-0-12), and general formula (a11-0-11) Having a structural unit represented by the general formula (a3-1) and a group represented by the general formula (I-1-1) at the end of the main chain, And the structural unit represented by the said general formula (a0-0-12), the structural unit represented by the said general formula (a11-0-12), and the structural unit represented by the said general formula (a1-511) Are preferred.

The weight average molecular weight (Mw) (polystyrene conversion standard by gel permeation chromatography (GPC)) of the polymer of the present invention is not particularly limited, preferably 1000 to 50000, more preferably 1500 to 30000, 2000 ˜20,000 is most preferred. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and if it is above the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
The dispersity (Mw / Mn) of the polymer of the present invention is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.0 to 2.5. In addition, Mn shows a number average molecular weight.

(Method for producing polymer)
As an example, the polymer of the present invention polymerizes a monomer containing at least a monomer that induces the structural unit (a0) by radical polymerization, anionic polymerization, or the like using a polymerization initiator having an anion moiety that generates an acid upon exposure. Can be obtained. Each monomer may be a commercially available monomer or a monomer synthesized using a known method.
Among these, the polymer of the present invention is a radical composed of a compound represented by the following general formula (I), because it is easier to obtain good lithography characteristics and pattern shape when used as a base resin in a resist composition. A radical polymer obtained by radical polymerization using a polymerization initiator is preferred.

［式中、Ｒ^１は炭素数１〜１０の炭化水素基であり、Ｚは炭素数１〜１０の炭化水素基又はシアノ基であり、Ｒ^１とＺとは相互に結合して環を形成していてもよい。Ｘは２価の連結基であって、−Ｏ−Ｃ（＝Ｏ）−、−ＮＨ−Ｃ（＝Ｏ）−、及び−ＮＨ−Ｃ（＝ＮＨ）−のいずれかを、少なくとも式中のＱと接する末端に有する。ｐは１〜３の整数である。Ｑは（ｐ＋１）価の炭化水素基であり、ｐが１の場合のみ、Ｑは単結合であってもよい。Ｒ^２は単結合、置換基を有していてもよいアルキレン基、又は置換基を有していてもよい芳香族基であり、ｑは０又は１であり、ｒは０〜８の整数である。Ｍ^＋は有機カチオンである。式中の複数のＲ^１、Ｚ、Ｘ、ｐ、Ｑ、Ｒ^２、ｑ、ｒ、Ｍ^＋はそれぞれ同じであっても異なっていてもよい。］

[Wherein, R ¹ is a hydrocarbon group having 1 to 10 carbon atoms, Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group, and R ¹ and Z are bonded to each other to form a ring. You may do it. X is a divalent linking group, and at least one of —O—C (═O) —, —NH—C (═O) —, and —NH—C (═NH) — It is at the end that contacts Q. p is an integer of 1 to 3. Q is a (p + 1) -valent hydrocarbon group, and Q may be a single bond only when p is 1. R ² is a single bond, an alkylene group which may have a substituent, or an aromatic group which may have a substituent, q is 0 or 1, and r is an integer of 0 to 8. is there. M ⁺ is an organic cation. A plurality of R ¹ , Z, X, p, Q, R ² , q, r, and M ⁺ in the formula may be the same or different. ]

In the formula (I), R ¹ , Z, X, p, Q, R ² , q, r, and M ⁺ are R ¹ , Z, X, p, Q, and R ^{2 in the} formula (I-1). , Q, r, M ⁺ are the same.
The monomer to be radically polymerized may be any monomer as long as it can be radically polymerized with the monomer that induces the structural unit (a0) and the monomer that induces the structural unit (a0), and is appropriately selected depending on the polymer to be produced. Is done.
The radical polymerization can be carried out using a known method except that the compound represented by the formula (I) is used as a radical polymerization initiator.
In radical polymerization, one radical polymerization initiator may be used alone, or two or more radical polymerization initiators may be used in combination.

  Below, the manufacture example of the polymer of this invention is shown. In the following production examples, a radical polymerization initiator composed of a compound represented by the formula (I) (hereinafter referred to as “radical polymerization initiator (I)”) is used to represent the formula (a0-0-0). A synthesis route in which a monomer (a monomer for deriving a structural unit represented by the above formula (a0-0); hereinafter referred to as “monomer (a0-0-0)”) is radically polymerized is schematically shown. However, the synthesis route of the polymer is not limited to the following production examples.

［式中、Ｒ^１、Ｚ、Ｘ、ｐ、Ｑ、Ｒ^２、ｑ、ｒ、Ｍ^＋は、前記式（Ｉ−１）におけるＲ^１、Ｚ、Ｘ、ｐ、Ｑ、Ｒ^２、ｑ、ｒ、Ｍ^＋と同じである。Ｒ、Ｒ^４０、Ｒ^３０、Ｒ^２９’は前記式（ａ０−０）におけるＲ、Ｒ^４０、Ｒ^３０、Ｒ^２９’と同じである。］

[Wherein R ¹ , Z, X, p, Q, R ² , q, r, M ⁺ represent R ¹ , Z, X, p, Q, R ² , q, in the formula (I-1). Same as r and M ⁺ . ^{R, R 40, R 30,} R 29 ' is ^{R, R 40, R 30,} R 29 in the formula (a0-0)' is the same as. ]

In the synthesis route, the radical polymerization initiator (I) is decomposed by the action of heat or light to generate nitrogen gas (N ₂ ) and carbon radicals.
Next, the carbon radical acts on the monomer (a0-0-0), and the polymerization of the monomers (a0-0-0) proceeds to obtain the polymer (PI).
The resulting polymer (P-I) has an anion moiety that generates an acid upon exposure at one end of the main chain. This “anion portion that generates an acid upon exposure” is a residue derived from the radical polymerization initiator (I) (the above-mentioned end group (I-1)).

  The radical polymerization initiator (I) is preferably a compound represented by any one of the following general formulas (I1) to (I5).

［式中、Ｒ^１、Ｚ、Ｑ、ｐ、Ｍ^＋は前記同様である。Ｘ^０１は単結合又は置換基を有していてもよいアルキレン基であり、Ｒ^２１は単結合又は置換基を有していてもよいアルキレン基であり、Ｘ^０２は置換基を有していてもよいアルキレン基であり、Ｒ^２２は置換基を有していてもよい芳香族基である。式中の複数のＲ^１、Ｚ、Ｑ、ｐ、Ｍ^＋、Ｘ^０１、Ｒ^２１、Ｘ^０２、Ｒ^２２はそれぞれ同じであっても異なっていてもよい。］

[Wherein, R ¹ , Z, Q, p and M ⁺ are the same as described above. X ⁰¹ is an alkylene group which may have a single bond or a substituent, R ²¹ is an alkylene group which may have a single bond or a substituent, and X ⁰² has a substituent. R ²² is an aromatic group which may have a substituent. A plurality of R ¹ , Z, Q, p, M ⁺ , X ⁰¹ , R ²¹ , X ⁰² and R ²² in the formula may be the same or different. ]

Wherein ^{(I1) ~ (I5),} R 1, Z, X 01, Q, p, M + , the formula (I-1-1) ^R 1 in the ~ (I-1-5), Z , X ^{This is the same as 01} , Q, p, M ⁺ .
Wherein ^{(I1) ~ (I3),} R 21 is the same as ^{R 21} in the formula (I-1-1) ~ (I -1-3).
Wherein ^{(I3), X 02} is the same as ^{X 02} in Formula (I-1-3).
Wherein ^{(I4) ~ (I5),} R 22 is the formula (I-1-4), is the same as ^{R 22} in the (I-1-5).

Specific examples of the compounds represented by any of the above formulas (I1) to (I5) are shown below. In the following formula, M ⁺ is the same as described above.

Among these, as the radical polymerization initiator (I), a compound represented by any one of the formulas (I1) to (I5) is preferable, and a compound represented by the formula (I1) is particularly preferable.
Further, as the organic cation of M ⁺ , an organic cation represented by any one of the formulas (c-1) to (c-3) is preferable, and an organic cation represented by the formula (c-1) is particularly preferable. .

  Although the manufacturing method of radical polymerization initiator (I) is not specifically limited, The compound (henceforth "compound (i-1)") represented by the following general formula (i-1), A production method including a step of reacting a compound represented by the following general formula (i-2) (hereinafter also referred to as “compound (i-2)”) is preferable.

［式中、Ｒ^１、Ｚ、Ｘ、Ｑ、ｐ、ｑ、Ｒ^２、ｒ、Ｍ^＋はそれぞれ前記同様であり、Ｂ^１、Ｂ^２はそれぞれ独立にＨ又はＯＨである。式中の複数のＲ^１、Ｚ、Ｘ、ｐ、Ｑ、Ｂ^１はそれぞれ同じであっても異なっていてもよい。］

[Wherein, R ¹ , Z, X, Q, p, q, R ² , r, and M ⁺ are the same as defined above, and B ¹ and B ² are each independently H or OH. A plurality of R ¹ , Z, X, p, Q, and B ¹ in the formula may be the same or different. ]

In formula (i-1), if terminus of B ¹ side of Q is an oxygen atom, or Q is the terminal oxygen atom of B ¹ side of a is and X single bond, B ¹ is H It is preferable. On the other hand, when the terminal on the B ¹ side of Q is not an oxygen atom, or when Q is a single bond and the terminal on the B ¹ side of X is not an oxygen atom, B ¹ is preferably OH.
In the formula (i-2), when q is 1, B ² is preferably H. On the other hand, when q is 0, B ² is preferably OH.

As compound (i-1) and compound (i-2), commercially available compounds or synthesized compounds may be used, respectively.
As a method of obtaining the radical polymerization initiator (I) by reacting the compound (i-1) and the compound (i-2), the compound (i-2) and the compound (i) are present in the presence of a condensing agent or a base. And -1) in an organic solvent, and then the reaction mixture is washed and recovered.

Examples of the condensing agent in the above reaction include compounds containing a carbodiimide group such as diisopropylcarbodiimide, and one kind may be used alone, or two or more kinds may be used in combination. As for the usage-amount of a condensing agent, about 0.01-10 mol is preferable with respect to 1 mol of compounds (i-2).
Examples of the base in the above reaction include tertiary amines such as potassium carbonate and triethylamine, and aromatic amines such as pyridine. One kind may be used alone, or two or more kinds may be used in combination. The amount of the base used is usually preferably about 0.01 to 10 mol with respect to 1 mol of compound (i-2).
The organic solvent in the above reaction is preferably a chlorinated hydrocarbon solvent such as dichloromethane. The amount of the organic solvent used is preferably 0.5 to 100 parts by mass and more preferably 0.5 to 20 parts by mass with respect to compound (i-2). An organic solvent may be used individually by 1 type, and may use 2 or more types together.
When p is 1, the amount of compound (i-2) used in the above reaction is usually preferably about 0.5 to 5 mol, preferably 0.8 to 4 mol, relative to 1 mol of compound (i-1). The degree is more preferable.

The reaction time in the above reaction varies depending on the reactivity between the compound (i-1) and the compound (i-2), the reaction temperature, etc., but is usually preferably 1 to 80 hours, more preferably 3 to 60 hours. .
20-200 degreeC is preferable and, as for the reaction temperature in the said reaction, about 20-150 degreeC is more preferable.

  After completion of the reaction, the radical polymerization initiator (I) in the reaction solution may be isolated and purified. For isolation and purification, conventionally known methods can be used. For example, concentration, solvent extraction, distillation, crystallization, recrystallization, chromatography, etc. can be used alone or in combination of two or more thereof. it can.

The structure of the radical polymerization initiator (I) obtained as described above includes ¹ H-nuclear magnetic resonance (NMR) spectrum method, ¹³ C-NMR spectrum method, ¹⁹ F-NMR spectrum method, infrared absorption (IR) spectrum. It can be confirmed by a general organic analysis method such as a method, mass spectrometry (MS) method, elemental analysis method, X-ray crystal diffraction method.

Further, as another method for producing the polymer of the present invention, by using the compound (I0) represented by the following general formula (I0) as a radical polymerization initiator, the following general formula ( polymer having a group represented by I-01) (to give a precursor polymer), the precursor to the main chain terminal groups of the body weight polymer ^{_{"- (OCO) q -R 2 -}} (CF 2) r -SO ₃ ^- M ⁺ ”(q, R ² , r, M ⁺ are the same as described above) is introduced (a hydrogen atom at the end of the main chain is substituted). As compound (I-01), known compounds can be used.
^{_{"- (OCO) q -R 2 -}} (CF 2) r -SO 3 - M + " introduction can be carried out by a conventional method, for example, precursor polymer and the following general formula ( It can be carried out by reacting the compound (i-02) represented by i-02). This reaction can be carried out in the same manner as in the method of reacting compound (i-1) and compound (i-2) described above.

［式中、Ｒ^１、Ｚ、Ｘ、Ｑ、ｐ、ｑ、Ｒ^２、ｒ、Ｍ^＋、Ｂ^１、Ｂ^２はそれぞれ前記同様である。］

[Wherein R ¹ , Z, X, Q, p, q, R ² , r, M ⁺ , B ¹ and B ² are the same as defined above. ]

Since the polymer of the present invention described above has an anion site that generates an acid by exposure at least at one end of the main chain, it has an acid generating ability to generate an acid by exposure. As an example, the group represented by the general formula (I-1) (terminal group (I-1)) has a sulfonium salt moiety at the terminal, so that sulfonic acid is generated by exposure.
In addition, the polymer of the present invention has a structural unit (a0) containing a —SO ₂ — containing cyclic group. Thereby, the adhesiveness to the board | substrate of the resist film formed using the resist composition containing this polymer increases. Further, since the structural unit (a0) has a large interaction with the acid generator component contained in the resist composition, the acid generator component resist film can be obtained by having the structural unit (a0) in the polymer. It is considered that the internal distribution is easily uniformized.

The polymer of the present invention is useful for a resist composition. Although it does not specifically limit as a resist composition with which the said polymer is mix | blended, The base component which the solubility with respect to an alkali developing solution changes with the effect | action of an acid, and the acid generator component which generate | occur | produces an acid by exposure are contained. A chemically amplified resist composition is preferred.
The polymer of the present invention is particularly useful as a base component of a chemically amplified resist composition or as an additive component arbitrarily blended in the resist composition and used as a base component. Particularly preferred.

≪Resist composition≫
The resist composition of the present invention contains the polymer of the present invention. Since a resist film formed using such a resist composition contains the polymer of the present invention, it has a function of generating an acid upon exposure.
In addition, since the resist film contains the polymer of the present invention, it is possible to form a pattern using a component whose solubility is changed by the action of an acid even when the acid generator component is not included separately. Become. On the other hand, when an acid generator component other than the polymer of the present invention is contained, the sensitivity is further improved as compared with the case where the polymer of the present invention is not contained.

The resist composition of the present invention may be a negative resist composition or a positive resist composition.
In this specification, a resist composition that forms a positive pattern in which an exposed portion is dissolved and removed is referred to as a positive resist composition, and a resist composition that forms a negative pattern in which an unexposed portion is dissolved and removed is referred to as a negative. This is referred to as a type resist composition.

Further, the resist composition of the present invention may be a non-chemical amplification type or a chemical amplification type. In particular, the resist composition of the present invention is preferably a chemically amplified resist composition because it contains a polymer that generates an acid upon exposure from the main chain end. In addition, a chemically amplified resist composition is preferable because a resist pattern can be formed with higher sensitivity and higher resolution.
In general, a chemically amplified resist composition generally contains a base material component whose solubility in a developing solution is changed by the action of an acid and an acid generator component that generates an acid upon exposure. When the resist composition is exposed to light, an acid is generated from the acid generator component, and the solubility of the base material component in the developer is changed by the action of the acid. Therefore, in the formation of the resist pattern, when the resist film formed using the resist composition is selectively exposed, the solubility of the exposed portion in the developer changes (in the case of the positive type, the increase in the case of the negative type, On the other hand, since the solubility of the unexposed portion in the alkaline developer does not change, the resist pattern is formed by developing this.

As described above, in the chemically amplified resist composition, a base material component whose solubility in a developer is changed by the action of an acid is usually used.
Here, the “base material component” is an organic compound having a film forming ability, and an organic compound having a molecular weight of 500 or more is preferably used. When the molecular weight of the organic compound is 500 or more, the film-forming ability is improved and a nano-level resist pattern is easily formed. “Organic compounds having a molecular weight of 500 or more” used as the base component are roughly classified into non-polymers and polymers. As the non-polymer, those having a molecular weight of 500 or more and less than 4000 are usually used. Hereinafter, a nonpolymer having a molecular weight of 500 or more and less than 4000 is referred to as a low molecular compound. As the polymer, those having a molecular weight of 1000 or more are usually used. Hereinafter, a polymer having a molecular weight of 1000 or more is referred to as a polymer compound. In the case of a polymer compound, the “molecular weight” is a polystyrene-reduced mass average molecular weight measured by GPC (gel permeation chromatography). Hereinafter, the polymer compound may be simply referred to as “resin”.

The resist composition of the present invention may contain the above-described polymer of the present invention as a resin constituting the base component whose solubility in the developer is changed by the action of an acid; You may contain the polymer of the said invention with other resin. That is, when the polymer of the present invention is used in the resist composition of the present invention, the polymer of the present invention may be one whose solubility in a developing solution is changed by the action of an acid, and the others. It may be.
Especially, it is preferable that the polymer of the said invention used for the resist composition of this invention changes the solubility with respect to a developing solution by the effect | action of an acid, and is used as a base-material component.
As described above, the polymer of the present invention has an anion site that generates an acid upon exposure at the end of the main chain. In addition to this, when the solubility of the polymer in the developer is changed by the action of an acid, the anion site and a site contributing to the solubility change by the acid in the polymer (specifically, for example, , The structural unit (a1) and the like are uniformly distributed in the resist film, and in the exposed portion, an acid is uniformly generated from the polymer, and the solubility of the polymer itself is suitably changed. Good lithographic properties can be obtained.

That is, the resist composition of the present invention contains a base component (A) (hereinafter also referred to as “component (A)”) that changes its solubility in a developing solution by the action of an acid and generates an acid upon exposure. The component (A) preferably contains the polymer of the present invention.
The resist composition of the present invention includes a component (A) and an acid generator component (B) that generates an acid upon exposure (excluding the base material component (A)) (hereinafter referred to as “(B)”. It is also preferable that the component (A) contains the polymer of the present invention.
Hereinafter, the resist composition containing the polymer of the present invention as the component (A) will be described.

<(A) component>
When the resist composition of the present invention is a “negative resist composition for an alkali development process” that forms a negative pattern in an alkali development process, a base component that is soluble in an alkali developer is used as the component (A). Furthermore, a crosslinking agent component is blended.
When an acid is generated from the polymer of the present invention contained in the component (A) by exposure, the negative resist composition for alkali development process acts between the base component and the crosslinking agent component when the acid acts. Crosslinking occurs and changes to poorly soluble in an alkaline developer. Therefore, in the formation of a resist pattern, when a resist film obtained by applying the negative resist composition on a support is selectively exposed, the exposed portion turns into poorly soluble in an alkaline developer, while not yet exposed. Since the exposed portion remains soluble in the alkali developer and does not change, a resist pattern can be formed by alkali development.
As the component (A) of the negative resist composition for an alkali development process, a resin that is soluble in an alkali developer (hereinafter referred to as “alkali-soluble resin”) is usually used.
Examples of the alkali-soluble resin include α- (hydroxyalkyl) acrylic acid or α- (hydroxyalkyl) acrylic acid alkyl ester (preferably having 1 to 5 carbon atoms) disclosed in, for example, JP-A-2000-206694. A resin having a unit derived from at least one selected from alkyl ester); a hydrogen atom bonded to a carbon atom at the α-position having a sulfonamide group, which is disclosed in US Pat. No. 6,949,325, is substituted with a substituent. Acrylic resin or polycycloolefin resin which may be contained; disclosed in US Pat. No. 6,949,325, Japanese Patent Application Laid-Open No. 2005-336452, and Japanese Patent Application Laid-Open No. 2006-317803, which contains a fluorinated alcohol and is in the α-position. The hydrogen atom bonded to the atom may be substituted with a substituent. Le resin; Japanese Patent disclosed in 2006-259582, JP-polycycloolefin resins having fluorinated alcohol, with minimal swelling can formation of a satisfactory resist pattern.
The α- (hydroxyalkyl) acrylic acid is a hydrogen atom bonded to the α-position carbon atom to which the carboxy group is bonded, among the acrylic acid in which the hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent. One or both of acrylic acid having an atom bonded thereto and α-hydroxyalkylacrylic acid having a hydroxyalkyl group (preferably a hydroxyalkyl group having 1 to 5 carbon atoms) bonded to the α-position carbon atom are shown. .
As the crosslinking agent component, for example, it is usually preferable to use an amino crosslinking agent such as glycoluril having a methylol group or an alkoxymethyl group, a melamine crosslinking agent, or the like because a good resist pattern with less swelling can be formed. It is preferable that the compounding quantity of a crosslinking agent component is 1-50 mass parts with respect to 100 mass parts of alkali-soluble resin.

When the resist composition of the present invention is a resist composition that forms a positive pattern in an alkali development process and a negative pattern in a solvent development process, the component (A) has increased polarity due to the action of an acid. It is preferable to use the base material component (A0) (hereinafter referred to as “(A0) component”). By using the component (A0), the polarity of the base material component changes before and after exposure, so that good development contrast can be obtained not only in the alkali development process but also in the solvent development process.
When the alkali development process is applied, the component (A0) is hardly soluble in an alkali developer before exposure, and when acid is generated from the polymer of the present invention contained in the component (A) by exposure, The polarity is increased by the action of the acid, and the solubility in an alkaline developer is increased. Therefore, in the formation of a resist pattern, when a resist film obtained by applying the resist composition on a support is selectively exposed, the exposed portion changes from slightly soluble to soluble in an alkaline developer. Since the unexposed portion remains hardly soluble in alkali and does not change, a positive pattern can be formed by alkali development.
In addition, when applying a solvent development process, the component (A0) is highly soluble in an organic developer before exposure, and is exposed to acid from the polymer of the present invention contained in the component (A) by exposure. When this occurs, the polarity increases due to the action of the acid and the solubility in an organic developer decreases. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the resist composition on the support is selectively exposed, the exposed portion changes from soluble to poorly soluble in an organic developer. On the other hand, since the unexposed portion remains soluble and does not change, by developing with an organic developer, a contrast can be provided between the exposed portion and the unexposed portion, and a negative pattern can be formed.

In the resist composition of the present invention, the component (A) is preferably a base material component ((A0) component) whose polarity is increased by the action of an acid. That is, the resist composition of the present invention is preferably a chemically amplified resist composition that becomes positive in the alkali development process and negative in the solvent development process.
Among them, in the resist composition of the present invention, the component (A) is composed of the polymer of the present invention, and its polarity is increased by the action of an acid (A1) (hereinafter also referred to as “(A1) component”). It is particularly preferable to contain

[(A1) component]
The component (A1) is a polymer having an anion site that generates an acid upon exposure to at least one end of the main chain and having the structural unit (a0), and the polarity increases by the action of the acid. Is.
Among these, as the component (A1), a copolymer having an anion site that generates an acid upon exposure at least at one end of the main chain and having the structural unit (a0) and the structural unit (a1). Combined (A1-1) (hereinafter referred to as “component (A1-1)”) is preferred.
The component (A1) is preferably a copolymer further having the structural unit (a3) in the component (A1-1).
The component (A1) is a component other than the structural unit (the structural unit (a2), (a4), etc.) in the component (A1-1), together with the structural unit (a3), or the structural unit (a3). You may have further instead of.
For the explanation of the component (A1-1), in the polymer of the present invention, “at least one terminal of the main chain has an anion moiety that generates an acid upon exposure, and the constituent unit (a0) and the constituent This is the same as described for the “copolymer having the unit (a1)”.

[(A2) component]
In the resist composition of the present invention, as a component (A), a base material component (hereinafter referred to as “component (A2)”) which does not correspond to the component (A1) and whose solubility in a developing solution is changed by the action of an acid. You may contain.
As the component (A2), a low molecular compound having a molecular weight of 500 or more and less than 2500 and having an acid dissociable group and a hydrophilic group as exemplified in the description of the component (A1) above can be suitably exemplified. . Specific examples include those in which some of the hydrogen atoms of the hydroxyl group of the compound having a plurality of phenol skeletons are substituted with the acid dissociable group.
The component (A2) is, for example, a part of the hydrogen atom of the hydroxyl group of a low molecular weight phenol compound known as a sensitizer in a non-chemically amplified g-line or i-line resist or a heat resistance improver. Those substituted with a functional group are preferred and can be arbitrarily used.
Examples of such low molecular weight phenol compounds include bis (4-hydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) methane, 2- (4-hydroxyphenyl) -2- (4′-hydroxyphenyl). ) Propane, 2- (2,3,4-trihydroxyphenyl) -2- (2 ′, 3 ′, 4′-trihydroxyphenyl) propane, tris (4-hydroxyphenyl) methane, bis (4-hydroxy-) 3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3, 4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3,4-dihydroxyph Phenylmethane, bis (4-hydroxy-3-methylphenyl) -3,4-dihydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl- 4-hydroxy-6-methylphenyl) -3,4-dihydroxyphenylmethane, 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, Examples include 2 to 6 nuclei of formalin condensates of phenols such as phenol, m-cresol, p-cresol and xylenol. Of course, it is not limited to these. In particular, a phenol compound having 2 to 6 triphenylmethane skeletons is preferable because of excellent resolution and LWR.
The acid dissociable group is not particularly limited, and examples thereof include those described above.

Moreover, it is also preferable to use the resin component which does not correspond to the said (A1) component as (A2) component. Specifically, as the resin component not corresponding to the component (A1), those not corresponding to the polymer of the present invention, for example, other known radical polymerization initiators are used without using the radical polymerization initiator (I). And polymers produced by the above method. The configuration of the polymer is not particularly limited, and for example, those having the structural units (a1), (a2), (a3), and (a0) are preferable.
(A2) A component may be used individually by 1 type and may be used in combination of 2 or more type.

In the resist composition of the present invention, as the component (A), one type may be used alone, or two or more types may be used in combination.
In the resist composition of the present invention, the content of the component (A) may be adjusted according to the resist film thickness to be formed.

<Optional component>
[Component (B)]
The resist composition of the present invention may further contain an acid generator component (B) that generates an acid upon exposure.
When the resist composition of the present invention contains the component (B), the component (B) is not particularly limited, and it is possible to use what has been proposed as an acid generator for chemically amplified resists. it can. Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, and poly (bissulfonyl) diazomethanes. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.
As the onium salt acid generator, for example, a compound represented by the following general formula (b-1) or (b-2) can be used.

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

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

R ¹ ″ to R ³ ″ in Formula (b-1) and R ⁵ ″ to R ⁶ ″ in Formula (b-2) are respectively R ¹ ″ to R ^{3 in} Formula (c-1). ", The same as R ⁵ " to R ⁶ "in the formula (c-2).

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

Examples of the substituent include a halogen atom, a heteroatom, an alkyl group, and a formula: X ³ -Q ^1- [wherein Q ¹ is a divalent linking group containing an oxygen atom, and X ³ represents a substituent. It is a C3-C30 hydrocarbon group which may have. ] Etc. which are represented by these.
Examples of the halogen atom and alkyl group include the same groups as those described above for R ⁴ ″ as the halogen atom and alkyl group in the halogenated alkyl group.
Examples of the hetero atom include an oxygen atom, a nitrogen atom, and a sulfur atom.

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

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

The aliphatic hydrocarbon group for X ³ may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic.
In X ³ , the aliphatic hydrocarbon group may be a group in which a part of carbon atoms constituting the aliphatic hydrocarbon group may be substituted with a substituent containing a hetero atom, and hydrogen constituting the aliphatic hydrocarbon group A part or all of the atoms may be substituted with a substituent containing a hetero atom.
The “heteroatom” in X ³ is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom.
The substituent containing a hetero atom may be composed of only the hetero atom, or may be a group containing a group or atom other than the hetero atom.
Specific examples of the substituent for substituting a part of the carbon atom include —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O. —, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group, an acyl group, etc.), —S—, —S (═O) ₂ —, — S (= O) ₂ —O— and the like can be mentioned. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent for substituting part or all of the hydrogen atoms include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and a cyano group.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.

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

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

The aliphatic cyclic group may be a monocyclic group or a polycyclic group. The number of carbon atoms is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12.
Specifically, for example, a group in which one or more hydrogen atoms have been removed from a monocycloalkane; a group in which one or more hydrogen atoms have been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which one or more hydrogen atoms have been removed from a monocycloalkane such as cyclopentane or cyclohexane; one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom.
When the aliphatic cyclic group does not contain a substituent containing a hetero atom in the ring structure, the aliphatic cyclic group is preferably a polycyclic group, and has one or more hydrogen atoms from the polycycloalkane. Excluded groups are preferred, and most preferred are groups in which one or more hydrogen atoms have been removed from adamantane.
When the aliphatic cyclic group includes a substituent containing a hetero atom in the ring structure, examples of the substituent containing a hetero atom include —O—, —C (═O) —O—, —S—. , —S (═O) ₂ — and —S (═O) ₂ —O— are preferable. Specific examples of the aliphatic cyclic group include the following formulas (L1) to (L6), (S1) to (S4), and the like.

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

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

In the formula, examples of the alkylene group for Q ″, R ⁹⁴ and R ⁹⁵ include the same alkylene groups as those described above for R ^{91 to} R ⁹³ .
In these aliphatic cyclic groups, a part of hydrogen atoms bonded to carbon atoms constituting the ring structure may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
As said alkyl group, a C1-C5 alkyl group is preferable, and it is especially preferable that they are a methyl group, an ethyl group, a propyl group, n-butyl group, and a tert- butyl group.
Examples of the alkoxy group and the halogen atom are the same as those exemplified as the substituent for substituting part or all of the hydrogen atoms.

In the present invention, X ³ is preferably a cyclic group which may have a substituent. The cyclic group may be an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a substituent. It is preferably an aliphatic cyclic group that may be used.
The aromatic hydrocarbon group is preferably a naphthyl group which may have a substituent or a phenyl group which may have a substituent.
As the aliphatic cyclic group which may have a substituent, a polycyclic aliphatic cyclic group which may have a substituent is preferable. The polycyclic aliphatic cyclic group is preferably a group obtained by removing one or more hydrogen atoms from the polycycloalkane, the above (L2) to (L6), (S3) to (S4), and the like.

In the present invention, R ⁴ ″ preferably has X ³ -Q ^1- as a substituent. In this case, R ⁴ ″ may be X ³ -Q ¹ -Y ^10- [wherein Q ¹ and X ^{1 3} is the same as above, and Y ¹⁰ is an optionally substituted alkylene group having 1 to 4 carbon atoms or an optionally substituted fluorinated alkylene group having 1 to 4 carbon atoms. . ] Is preferable.
In the group represented by X ³ -Q ¹ -Y ^10- , the alkylene group for Y ¹⁰ includes the same alkylene groups as those described above for Q ¹ having 1 to 4 carbon atoms.
Examples of the fluorinated alkylene group include groups in which part or all of the hydrogen atoms of the alkylene group have been substituted with fluorine atoms.
As Y ^10, _{specifically, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF (CF 2 CF 3) -, _{-C (CF 3) 2 -,} - CF 2 CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF ₃ ) —, —C (CF ₃ ) ₂ CF ₂ —, —CF (CF ₂ CF ₃ ) CF ₂ —, —CF (CF ₂ CF ₂ CF ₃ ) —, —C (CF ₃ ) (CF _{2 CF 3) -; - CHF} -, - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -, - CH (CF 3) CH 2 -, - CH (CF 2 _{CF 3) -, - C (} CH 3) (CF 3) -, - CH 2 CH 2 CH 2 CF 2 -, - _{CH 2 CH 2 CF 2 CF 2} -, - CH (CF 3) CH 2 CH 2 -, - CH 2 CH (CF 3) CH 2 -, - CH (CF 3) CH (CF 3) -, - C ( _{CF 3) 2 CH 2 -;} - CH 2 -, - CH 2 CH 2 -, - CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 -, - CH (CH 2 CH 3) -, - _{C (CH 3) 2 -,} - CH 2 CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 CH 2 -, - CH 2 CH (CH 3) CH 2 -, - CH (CH 3) CH _{(CH 3) -, - C} (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - CH (CH 2 CH 2 CH 3) -, - C (CH 3) (CH 2 CH ₃ ) — and the like.

Y ¹⁰ is preferably a fluorinated alkylene group, and particularly preferably a fluorinated alkylene group in which the carbon atom bonded to the adjacent sulfur atom is fluorinated. Examples of such fluorinated alkylene _{group, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF 2 CF 2 CF 2 CF 2 _{-, - CF (CF 3)} CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF 3) -, - C (CF 3) 2 CF 2 -, _{-CF (CF 2 CF 3) CF} 2 -; - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -; - CH 2 CH 2 CH 2 CF 2 -, - CH ₂ CH ₂ CF ₂ CF ₂ —, —CH ₂ CF ₂ CF ₂ CF ₂ — and the like can be mentioned.
Of _{these, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, or _CH 2 _CF 2 CF ₂ - is _{preferable, -CF 2 -, - CF 2} CF 2 - or -CF ₂ CF ₂ CF ₂ - is more preferable, -CF ₂ - is particularly preferred.

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

Specific examples of the onium salt acid generators represented by formulas (b-1) and (b-2) include diphenyliodonium trifluoromethanesulfonate or nonafluorobutanesulfonate, bis (4-tert-butylphenyl) iodonium. Trifluoromethane sulfonate or nonafluorobutane sulfonate, triphenylsulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, tri (4-methylphenyl) sulfonium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its Nonafluorobutanesulfonate, dimethyl (4-hydroxynaphthyl) sulfonium trifluoromethanesulfonate, its heptaful Lopropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of monophenyldimethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; trifluoromethanesulfonate of diphenylmonomethylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate (4-methylphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate, (4-methoxyphenyl) diphenylsulfonium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate , Trifluoromethanesulfonate of tri (4-tert-butyl) phenylsulfonium, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate, trifluoromethanesulfonate of diphenyl (1- (4-methoxy) naphthyl) sulfonium, its heptafluoropropane Sulfonate or its nonafluorobutane sulfonate, di (1-naphthyl) phenyl sulphonium trifluoromethane sulphonate, its heptafluoropropane sulphonate or its nonafluorobutane sulphonate; 1-phenyltetrahydrothiophenium trifluoromethane sulphonate, its heptafluoropropane sulphonate Or nonafluorobutanesulfonate thereof; 1- (4-methylphenyl) ) Tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropane sulfonate 1- (4-methoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1- (4-ethoxynaphthalene-1- Yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonaflu 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium trifluoromethanesulfonate, its heptafluoropropanesulfonate or its nonafluorobutanesulfonate; 1-phenyltetrahydrothiopyranium trifluoromethanesulfonate , Its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (4-hydroxyphenyl) tetrahydrothiopyranium trifluoromethane sulfonate, its heptafluoropropane sulfonate or its nonafluorobutane sulfonate; 1- (3,5-dimethyl -4-Hydroxyphenyl) tetrahydrothiopyranium trifluoromethanesulfonate, its heptafluoropropanes Honeto or nonafluorobutanesulfonate; 1- (4-methylphenyl) trifluoromethanesulfonate tetrahydrothiophenium Pila chloride, heptafluoropropane sulfonate or its nonafluorobutane sulfonate, and the like.
In addition, the anion part of these onium salts is an alkyl sulfonate such as methanesulfonate, n-propanesulfonate, n-butanesulfonate, n-octanesulfonate, 1-adamantanesulfonate, 2-norbornanesulfonate, d-camphor-10-sulfonate, An onium salt substituted with an aromatic sulfonate such as benzene sulfonate, perfluorobenzene sulfonate, or p-toluene sulfonate can also be used.

  Moreover, the onium salt which replaced the anion part of these onium salts by the anion part represented by either of following formula (b1)-(b9) can also be used.

［式中、ｑ１〜ｑ２はそれぞれ独立に１〜５の整数であり、ｑ３は１〜１２の整数であり、ｔ３は１〜３の整数であり、ｒ１〜ｒ２はそれぞれ独立に０〜３の整数であり、ｇは１〜２０の整数であり、Ｒ^７は置換基であり、ｎ１〜ｎ６はそれぞれ独立に０または１であり、ｖ０〜ｖ６はそれぞれ独立に０〜３の整数であり、ｗ１〜ｗ６はそれぞれ独立に０〜３の整数であり、Ｑ”は前記と同じである。］

[Wherein, q1 to q2 are each independently an integer of 1 to 5, q3 is an integer of 1 to 12, t3 is an integer of 1 to 3, and r1 to r2 are each independently 0 to 3] G is an integer of 1 to 20, R ⁷ is a substituent, n1 to n6 are each independently 0 or 1, v0 to v6 are each independently an integer of 0 to 3, w1 to w6 are each independently an integer of 0 to 3, and Q ″ is the same as above.]

As the substituent for R ^7, the same substituents as those described above for X ⁰³ as the substituent that the aliphatic hydrocarbon group may have and the substituent that the aromatic hydrocarbon group may have Is mentioned.
Code (r1 and r2, W1 to W6) attached to R ⁷ when is an integer of 2 or more, a plurality of the ^{R 7} groups may be the same, respectively, may be different.

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

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

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

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

Moreover, the sulfonium salt which has a cation part represented by the said Formula (c-3) can also be used as an onium salt type | system | group acid generator. The anion part of the sulfonium salt having a cation part represented by the formula (c-3) is not particularly limited, and may be the same as the anion part of the onium salt acid generators proposed so far. Examples of the anion moiety include fluorinated alkyl sulfonate ions such as the anion moiety (R ⁴ ″ SO ₃ ⁻ ) of the onium salt acid generator represented by the general formula (b-1) or (b-2). An anion represented by the above general formula (b-3) or (b-4).

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

［式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。］

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

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

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

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

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

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

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

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

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

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Further, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [Chemical 18] to [Chemical 19]), pamphlet of International Publication No. 04/074242, An oxime sulfonate-based acid generator disclosed in Examples 1 to 40) on pages 65 to 86 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

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

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

[(D) component]
The resist composition of the present invention preferably further contains a nitrogen-containing organic compound component (D) (hereinafter referred to as “component (D)”) as an optional component.
The component (D) is not particularly limited as long as it acts as an acid diffusion control agent, that is, a quencher that traps the acid generated from the components (A1) and (B) by exposure, and already has a wide variety. Any known one may be used arbitrarily. Of these, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are preferred.
An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms.
Examples of the aliphatic amine include an amine (alkyl amine or alkyl alcohol amine) or a cyclic amine in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms.
Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di- -Dialkylamines such as n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine , Trialkylamines such as tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decylamine, tri-n-dodecylamine; diethanolamine, triethanolamine, diisopropanolamine, Li isopropanolamine, di -n- octanol amines, alkyl alcohol amines tri -n- octanol amine. Among these, a trialkylamine having 5 to 10 carbon atoms is more preferable, and tri-n-pentylamine or tri-n-octylamine is particularly preferable.

Examples of the cyclic amine include heterocyclic compounds containing a nitrogen atom as a hetero atom. The heterocyclic compound may be monocyclic (aliphatic monocyclic amine) or polycyclic (aliphatic polycyclic amine).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
As the aliphatic polycyclic amine, those having 6 to 10 carbon atoms are preferable. Specifically, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5. 4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane, and the like.

  Other aliphatic amines include tris (2-methoxymethoxyethyl) amine, tris {2- (2-methoxyethoxy) ethyl} amine, tris {2- (2-methoxyethoxymethoxy) ethyl} amine, tris {2 -(1-methoxyethoxy) ethyl} amine, tris {2- (1-ethoxyethoxy) ethyl} amine, tris {2- (1-ethoxypropoxy) ethyl} amine, tris [2- {2- (2-hydroxy Ethoxy) ethoxy} ethyl] amine, triethanolamine triacetate and the like, and triethanolamine triacetate is preferable.

Moreover, you may use an aromatic amine as (D) component.
Aromatic amines include aniline, pyridine, 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, diphenylamine, triphenylamine, tribenzylamine, 2,6-diisopropylaniline, N-tert-butoxy. And carbonylpyrrolidine.

(D) A component may be used independently and may be used in combination of 2 or more type.
(D) component is normally used in 0.01-5.0 mass parts with respect to 100 mass parts of (A) component. By setting the content in the above range, the resist pattern shape, the stability over time, and the like are improved.

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

[(F) component]
The resist composition can contain a fluorine additive (hereinafter referred to as “component (F)”) in order to impart water repellency to the resist film. As the component (F), for example, a fluorine-containing polymer compound described in JP 2010-002870 A can be used.
More specifically, examples of the component (F) include a polymer having a structural unit (f1) represented by the following formula (f1-1). Examples of such a polymer include a polymer consisting of only the structural unit (f1) (homopolymer); a copolymer of the structural unit represented by the following formula (f1) and the structural unit (a1); ), A copolymer of the structural unit derived from acrylic acid or methacrylic acid, and the structural unit (a1). Here, as the structural unit (a1) copolymerized with the structural unit represented by the following formula (f1), the structural unit represented by the formula (a11-1) is preferable, and the formula (a1-1) The structural unit represented by -32) is particularly preferable.

［式中、Ｒは前記同様であり、Ｒ^４１およびＲ^４２はそれぞれ独立して水素原子、ハロゲン原子、炭素数１〜５のアルキル基、又は炭素数１〜５のハロゲン化アルキル基を表し、複数のＲ^４１またはＲ^４２は同じであっても異なっていてもよい。ａ１は１〜５の整数であり、Ｒ^７”はフッ素原子を含む有機基である。］

[Wherein, R is the same as defined above, and R ⁴¹ and R ⁴² each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, A plurality of R ⁴¹ or R ⁴² may be the same or different. a1 is an integer of 1 to 5, and R ⁷ ″ is an organic group containing a fluorine atom.]

In formula (f1-1), R is the same as described above. R is preferably a hydrogen atom or a methyl group.
In formula (f1-1), examples of the halogen atom for R ⁴¹ and R ⁴² include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. Examples of the alkyl group having 1 to 5 carbon atoms of R ⁴¹ and R ⁴² include the same as the alkyl group having 1 to 5 carbon atoms of R, and a methyl group or an ethyl group is preferable. Specific examples of the halogenated alkyl group having 1 to 5 carbon atoms of R ⁴¹ and R ⁴² include a group in which part or all of the hydrogen atoms of the alkyl group having 1 to 5 carbon atoms are substituted with a halogen atom. Can be mentioned. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable. The Above all ^{R 41, R 42,} a hydrogen atom, a fluorine atom, or an alkyl group of 1 to 5 carbon atoms is preferable, a hydrogen atom, a fluorine atom, a methyl group or an ethyl group, preferred.
In formula (f1-1), a1 is an integer of 1 to 5, preferably an integer of 1 to 3, and more preferably 1 or 2.

In formula (f1-1), R ⁷ ″ is an organic group containing a fluorine atom, and is preferably a hydrocarbon group containing a fluorine atom.
The hydrocarbon group containing a fluorine atom may be linear, branched or cyclic, and preferably has 1 to 20 carbon atoms, more preferably 1 to 15 carbon atoms. The carbon number of 1 to 10 is particularly preferable.
The hydrocarbon group containing a fluorine atom preferably has 25% or more of the hydrogen atoms in the hydrocarbon group fluorinated, more preferably 50% or more fluorinated, and 60% or more. Fluorination is particularly preferable because the hydrophobicity of the resist film during immersion exposure is increased.
Among these, as R ⁷ ″, a fluorinated hydrocarbon group having 1 to 5 carbon atoms is particularly preferable, and a methyl group, —CH ₂ —CF ₃ , —CH ₂ —CF ₂ —CF ₃ , —CH (CF ₃ ) _{2, -CH 2 -CH 2 -CF 3} , and most preferably _{-CH 2 -CH 2 -CF 2 -CF 2} -CF 2 -CF 3.

(F) As for the mass mean molecular weight (Mw) (polystyrene conversion reference | standard by gel permeation chromatography), 1000-50000 are preferable, 5000-40000 are more preferable, and 10000-30000 are the most preferable. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and if it is above the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
The dispersity (Mw / Mn) of the component (F) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5.

Component (F) is, for example, a monomer for deriving each structural unit such as dimethyl-2,2-azobis (2-methylpropionate) (V-601), azobisisobutyronitrile (AIBN). It can be obtained by polymerization by known radical polymerization using a radical polymerization initiator. In the polymerization, for example, a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination, so that —C (CF ₃ ) is terminally used. _{A 2-} OH group may be introduced. As described above, a copolymer into which a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom is introduced has reduced defects and LER (line edge roughness: uneven unevenness of line side walls). Effective for reduction.
As the monomer for deriving each structural unit, a commercially available monomer may be used, or a monomer produced by a known method may be used.

(F) A component may be used individually by 1 type and may use 2 or more types together.
(F) A component is used in the ratio of 0.5-10 mass parts per 100 mass parts of (A) component.

  The resist composition of the present invention further contains miscible additives as desired, for example, an additional resin for improving the performance of the resist film, a surfactant, a dissolution inhibitor, and a plasticizer for improving coatability. Stabilizers, colorants, antihalation agents, dyes, and the like can be added as appropriate.

[(S) component]
The resist composition of the present invention can be produced by dissolving the material in an organic solvent (hereinafter sometimes referred to as “(S) component”).
As the component (S), any component can be used as long as it can dissolve each component to be used to form a uniform solution. Conventionally, any one of known solvents for chemically amplified resists can be used. Two or more types can be appropriately selected and used.
For example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, 2-heptanone; Monohydric alcohols; compounds having an ester bond, such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, monomethyl ether, monoethyl of the polyhydric alcohols or compound having the ester bond Ethers such as ether, monopropyl ether, monobutyl ether and other monoalkyl ethers and monophenyl ether Derivatives of polyhydric alcohols such as compounds having a combination [in these, propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) are preferred]; cyclic ethers such as dioxane, methyl lactate Esters such as ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate; anisole, ethyl benzyl ether, cresyl methyl ether, diphenyl ether , Dibenzyl ether, phenetole, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene, etc. Examples of the solvent include dimethyl sulfoxide (DMSO).

These organic solvents may be used independently and may be used as 2 or more types of mixed solvents.
Among these, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), cyclohexanone, and EL are preferable.
Moreover, the mixed solvent which mixed PGMEA and the polar solvent is also preferable. The blending ratio (mass ratio) may be appropriately determined in consideration of the compatibility between PGMEA and the polar solvent, preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. It is preferable to be within the range.
More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Moreover, when mix | blending PGME as a polar solvent, the mass ratio of PGMEA: PGME becomes like this. Preferably it is 1: 9-9: 1, More preferably, it is 2: 8-8: 2, More preferably, it is 3: 7-7: 3.
In addition, as the component (S), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70:30 to 95: 5.
Furthermore, as the component (S), a mixed solvent of PGMEA and cyclohexanone or a mixed solvent of PGMEA, PGME and cyclohexanone is also preferable. In this case, the mixing ratio of the former is preferably PGMEA: cyclohexanone = 95-5: 10-90, and the mixing ratio of the latter is preferably PGMEA: PGME: cyclohexanone = 35-55. : 20-40: 15-35.

  (S) The usage-amount of a component is not specifically limited, It is a density | concentration which can be apply | coated to a board | substrate etc., and is suitably set according to a coating film thickness. Generally, it is used so that the solid content concentration of the resist composition is in the range of 1 to 20% by mass, preferably 2 to 15% by mass.

The resist composition of the present invention is excellent in lithography properties such as sensitivity, exposure margin, mask reproducibility, and roughness reduction, and pattern shape. The reason why such an effect is obtained is not clear, but is presumed as follows.
The polymer contained in the resist composition of the present invention has an anion site that generates an acid upon exposure at at least one end of the main chain. For this reason, it is considered that the sensitivity is improved by generating an acid from the terminal of the polymer in the exposed portion.
In addition, since the polymer has a group capable of generating an acid, the excessive diffusion of the generated acid is suppressed as compared with the case where only the low molecular weight acid generator such as the component (B) is used. Is done. In addition, when the polymer having the structural unit (a0) containing a —SO ₂ -containing cyclic group is added to the resist composition, the substrate adhesion of the formed resist film is increased. Further, since the structural unit (a0) has a large interaction with the acid generator component contained in the resist composition, the acid generator component resist film can be obtained by having the structural unit (a0) in the polymer. It is considered that the internal distribution is easily uniformized.
And by these synergistic actions, it is presumed that according to the resist composition of the present invention, the lithography characteristics and the pattern shape are improved.

  In addition, when the polymer contained in the resist composition of the present invention is a component (A1) whose polarity is increased by the action of an acid, an anion that generates an acid upon exposure of the main chain end of the component (A1). Since the site is uniformly distributed in the resist film and the acid is generated from the anion site uniformly in the exposed area, the acid-decomposable group in the (A1) component of the exposed area is likely to be uniformly decomposed. The effect is considered to be obtained particularly well. In addition, since the component (A1) has an anion moiety that generates an acid upon exposure, the acid generated from the anion moiety and the acid-decomposable group exist relatively close to each other, and the acid-decomposable group by the acid It is presumed that the above effect is particularly remarkable since the decomposition reaction of is likely to occur.

≪Resist pattern formation method≫
The resist pattern forming method of the present invention includes a step of forming a resist film on a support using the resist composition of the present invention, a step of exposing the resist film, and developing the resist film to form a resist pattern. Forming.
The resist pattern forming method of the present invention can be performed, for example, as follows.
That is, first, the resist composition of the present invention is applied onto a support with a spinner or the like, and a baking (post-apply bake (PAB)) treatment is performed, for example, at a temperature of 80 to 150 ° C. for 40 to 120 seconds, preferably A resist film is formed by applying for 60 to 90 seconds.
Next, the resist film is exposed through a mask (mask pattern) on which a predetermined pattern is formed using an exposure apparatus such as an ArF exposure apparatus, an electron beam drawing apparatus, or an EUV exposure apparatus, or a mask pattern. After performing selective exposure by drawing or the like by direct irradiation with an electron beam without passing through, baking (post-exposure baking (PEB)) treatment is performed, for example, at a temperature of 80 to 150 ° C. for 40 to 120 seconds, preferably 60 Apply for ~ 90 seconds.
Next, the resist film is developed.
The development treatment is performed using an alkaline developer in the case of an alkali development process, and using a developer (organic developer) containing an organic solvent in the case of a solvent development process.
A rinsing treatment is preferably performed after the development treatment. The rinse treatment is preferably a water rinse using pure water in the case of an alkali development process, and is preferably a rinse solution containing an organic solvent in the case of a solvent development process.
In the case of a solvent development process, after the development process or the rinse process, a process of removing the developer or rinse liquid adhering to the pattern with a supercritical fluid may be performed.
Drying is performed after development or rinsing. In some cases, a baking process (post-bake) may be performed after the development process. In this way, a resist pattern can be obtained.

The support is not particularly limited, and a conventionally known one can be used, and examples thereof include a substrate for electronic components and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.
Further, the support may be a substrate in which an inorganic and / or organic film is provided on the above-described substrate. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include organic films such as an organic antireflection film (organic BARC) and a lower organic film in a multilayer resist method.
Here, the multilayer resist method is a method in which at least one organic film (lower organic film) and at least one resist film (upper resist film) are provided on a substrate, and the resist pattern formed on the upper resist film is used as a mask. This is a method of patterning a lower organic film, and it is said that a pattern with a high aspect ratio can be formed. That is, according to the multilayer resist method, the required thickness can be secured by the lower organic film, so that the resist film can be thinned and a fine pattern with a high aspect ratio can be formed.
In the multilayer resist method, basically, a method of forming a two-layer structure of an upper resist film and a lower organic film (two-layer resist method), and one or more intermediate layers between the upper resist film and the lower organic film And a method of forming a multilayer structure of three or more layers (metal thin film etc.) (three-layer resist method).

The wavelength used for the exposure is not particularly limited, and ArF excimer laser, KrF excimer laser, F ₂ excimer laser, EUV (extreme ultraviolet), VUV (vacuum ultraviolet), EB (electron beam), X-ray, soft X-ray, etc. Can be done using radiation. The resist composition is highly useful for KrF excimer laser, ArF excimer laser, EB or EUV.

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

Examples of the alkali developer used for the development treatment in the alkali development process include a 0.1 to 10% by mass tetramethylammonium hydroxide (TMAH) aqueous solution.
The organic solvent contained in the organic developer used for the development process in the solvent development process is not particularly limited as long as it can dissolve the component (A) (component (A) before exposure). It can be selected as appropriate. Specifically, polar solvents such as ketone solvents, ester solvents, alcohol solvents, amide solvents, ether solvents, and hydrocarbon solvents can be used.
A known additive can be blended in the organic developer as required. Examples of the additive include a surfactant. The surfactant is not particularly limited. For example, ionic or nonionic fluorine-based and / or silicon-based surfactants can be used.
When the surfactant is blended, the blending amount is usually 0.001 to 5% by mass, preferably 0.005 to 2% by mass, and 0.01 to 0. 0% with respect to the total amount of the organic developer. 5 mass% is more preferable.
The development process can be carried out by a known development method, for example, a method in which a support is immersed in a developer for a certain period of time (dip method), a developer is raised on the surface of the support by surface tension, and is left for a certain period of time. (Paddle method), spraying developer on the surface of the support (spray method), coating the developer while scanning the developer coating nozzle at a constant speed on the support rotating at a constant speed The method to continue (dynamic dispensing method) etc. are mentioned.

As the organic solvent contained in the rinsing liquid used for the rinsing treatment after the development process in the solvent development process, for example, among the organic solvents mentioned as the organic solvent contained in the organic developer, those which are difficult to dissolve the resist pattern are appropriately used. You can select and use. Usually, at least one solvent selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents, amide solvents and ether solvents is used. Among these, at least one selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents and amide solvents is preferable, and at least one selected from alcohol solvents and ester solvents is preferable. More preferred are alcohol solvents.
The rinse treatment (washing treatment) using the rinse liquid can be performed by a known rinse method. Examples of the method include a method of continuously applying a rinsing liquid on a support rotating at a constant speed (rotary coating method), a method of immersing the support in a rinsing liquid for a predetermined time (dip method), and the surface of the support. And a method of spraying a rinse liquid (spray method).

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.
In the analysis by NMR, the internal standard of ¹ H-NMR and the internal standard of ¹³ C-NMR is tetramethylsilane (TMS). The internal standard of ¹⁹ F-NMR is hexafluorobenzene (however, the peak of hexafluorobenzene was set to −160 ppm).

[Synthesis Example 1: Synthesis of Compound Anion-A]
Under a nitrogen atmosphere, ACVA (28.0 g) and Anion-a (36.8 g) were added to dichloromethane (280 g), and the mixture was stirred at room temperature. Diisopropylcarbodiimide (27.8 g) was added thereto and stirred for 10 minutes. Thereafter, dimethylaminopyridine (2.44 g) was added as a catalyst and reacted at 30 ° C. for 24 hours. T-Butyl methyl ether (1400 g) was added to the suspended reaction solution and stirred for 30 minutes, and then the precipitated target product was filtered off and dried to obtain 20.8 g of Anion-A.
The obtained compound was subjected to NMR measurement, and the structure was identified from the following results.
¹ H-NMR (400 MHz, DMSO-d6): δ (ppm) = 4.61 (dt, 4H, CH2CF2), 2.40-2.65 (m, 8H, CH2CH2), 1.72 (s, 6H) , CH3), 1.66 (s, 6H, CH3).
¹⁹ F-NMR (376 MHz, DMSO-d6): δ (ppm) = − 111.4.
From the above results, it was confirmed that Anion-A had the following structure.

[Synthesis Example 2: Synthesis of Compound (IA)]
TPS-Br (10.50 g), Anion-A (8.70 g), dichloromethane (155.0 g) and pure water (78.0 g) were added to the beaker, and the mixture was stirred at room temperature for 1 hour. After liquid separation, the dichloromethane layer was repeatedly washed with pure water (78.0 g), and the organic layer was concentrated under reduced pressure to obtain 13.80 g of compound (IA) as a white solid. .
The obtained compound was subjected to NMR measurement, and the structure was identified from the following results.
¹ H-NMR (400 MHz, DMSO-d6): δ (ppm) = 7.78-7.90 (m, 30H, ArH), 4.61 (dt, 4H, CH 2 CF 2), 2.40-2.65 (M, 8H, CH2CH2), 1.72 (s, 6H, CH3), 1.66 (s, 6H, CH3).
¹⁹ F-NMR (376 MHz, DMSO-d6): δ (ppm) = − 111.4.
From the above results, it was confirmed that the compound (IA) had the following structure.

[Synthesis Examples 3-55: Synthesis of Compounds (IB) to (I-BB)]
In Synthesis Example 2, the same operation was performed except that the cation part of TPS-Br was changed to the cation (equal molar amount) shown in Tables 1 to 18 below and synthesized. Thereby, the compounds (IB) to (I-BB) shown in Tables 1 to 18 were obtained.
Each compound was analyzed by NMR, and the results are shown in Tables 1-18.

Example 1 Synthesis of Polymer Compound (1) 13.2 g of γ-butyrolactone was placed in a flask connected with a thermometer, a reflux tube, a stirrer, and a nitrogen introduction tube under a nitrogen atmosphere, and the internal temperature was increased while stirring. Raised to 85 ° C.
5.0 g (15.8 mmol) of monomer (1), 4.6 g (19.5 mmol) of monomer (2), 1.9 g (8.2 mmol) of monomer (3) and 79.6 g of γ-butyrolactone Dissolved in. To this solution, 3.43 g of the compound (IA) as a radical polymerization initiator was added and dissolved.
This mixed solution was dropped into the flask at a constant rate over 4 hours, and then heated and stirred for 1 hour to cool the reaction solution to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of a methanol / water mixed solution to precipitate a polymer, and the precipitated white powder was filtered off, washed with a methanol / water mixed solution, and then dried under reduced pressure. Then, 5.7 g of the target polymer compound (1) was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound (1) was 7500, and the molecular weight dispersity (Mw / Mn) was 1.71.
Moreover, the composition ratio (ratio (molar ratio) of each structural unit in the structural formula) of the copolymer determined by ¹³ C-NMR was 1 / m / n = 40/40/20.

[Examples 2 to 21] Synthesis of polymer compounds (2) to (21) Polymer compounds (2) to (21) were prepared from the following monomers (1) to ( 20) was used in the same manner as in Example 1 except that the molar ratio shown in Table 19 was used.
For the obtained polymer compounds (2) to (21), Table 19 shows the polymerization initiator used, the mass average molecular weight (Mw), and the molecular weight dispersity (Mw / Mn).

[Comparative Example 1] Synthesis of polymer compound (22) 13.2 g of γ-butyrolactone was placed in a flask connected with a thermometer, a reflux tube, a stirrer, and a nitrogen introduction tube under a nitrogen atmosphere, and the internal temperature was increased while stirring. Raised to 85 ° C.
5.0 g (15.8 mmol) of monomer (1), 4.6 g (19.5 mmol) of monomer (2), 1.9 g (8.2 mmol) of monomer (3) and 79.6 g of γ-butyrolactone Dissolved in. To this solution, 0.72 g of dimethyl azobisisobutyrate (V-601, manufactured by Wako Pure Chemical Industries, Ltd.) was added and dissolved as a radical polymerization initiator.
This mixed solution was dropped into the flask at a constant rate over 4 hours, and then heated and stirred for 1 hour to cool the reaction solution to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of a methanol / water mixed solution to precipitate a polymer, and the precipitated white powder was filtered off, washed with a methanol / water mixed solution, and then dried under reduced pressure. Then, 8.1 g of the target polymer compound (22) was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound (22) was 6900, and the molecular weight dispersity (Mw / Mn) was 1.73.
Moreover, the composition ratio (ratio (molar ratio) of each structural unit in the structural formula) of the copolymer determined by ¹³ C-NMR was 1 / m / n = 40/40/20.

[Comparative Examples 2 to 21] Synthesis of Polymer Compounds (23) to (42) The polymer compounds (23) to (42) are the following monomers (1) to (1) for deriving structural units constituting each polymer compound. 20) was used in the same manner as Comparative Example 1 except that the molar ratio shown in Table 20 was used.
For the obtained polymer compounds (23) to (42), Table 20 shows the polymerization initiator used, the mass average molecular weight (Mw), and the molecular weight dispersity (Mw / Mn).

[Comparative Example 22] Synthesis of polymer compound (43) The polymer compound (43) comprises the following monomer (7), monomer (2) and monomer (3) for deriving structural units constituting the polymer compound. It was manufactured in the same manner as in Example 1 except that the molar ratio shown in Table 20 was used.
For the obtained polymer compound (43), the polymerization initiator used, the mass average molecular weight (Mw) and the molecular weight dispersity (Mw / Mn) are shown in Table 20.

[Examples 22 to 42, Comparative Examples 23 to 44] Preparation of resist compositions Resist compositions were prepared by mixing and dissolving the components shown in Tables 21 to 24.

Each abbreviation in Tables 21 to 24 has the following meaning. Moreover, the numerical value in [] is a compounding quantity (mass part).
(A) -1 to (A) -43: The polymer compounds (1) to (43).
(B) -1: The following compound (B) -1.
(D) -1: tri-n-octylamine.
(E) -1: salicylic acid.
(F) -1: produced by radical polymerization with the following polymer compound (F) -1 [l = 100 (molar ratio), Mw = 22000, Mw / Mn = 1.58, radical polymerization initiator V-601 Polymer].
(S) -1: PGMEA / PGME / cyclohexanone = 45/30/25 (mass ratio) mixed solvent.

[Formation of resist pattern]
An organic antireflection film composition “ARC95” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto a 12-inch silicon wafer using a spinner, and baked at 205 ° C. for 90 seconds on a hot plate and dried. Thereby, an organic antireflection film having a thickness of 90 nm was formed.
Then, the resist composition of each example was applied onto the organic antireflection film using a spinner, and prebaked (PAB) treatment was performed on the hot plate at the temperatures shown in Tables 25 and 26 for 60 seconds. By performing and drying, a resist film having a film thickness of 100 nm was formed.
Next, an ArF excimer laser was used with an ArF immersion exposure apparatus NSR-S609B (manufactured by Nikon Corporation; NA (numerical aperture) = 1.07, Dipole (in / out: 0.78 / 0.97), w / POLANO). (193 nm) was selectively irradiated through a mask pattern (6% halftone).
Then, a post-exposure heating (PEB) treatment was performed for 60 seconds at the temperatures shown in Tables 25 and 26, and a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution “NMD-3” (trade name) at 23 ° C. Developed by Tokyo Ohka Kogyo Co., Ltd.) for 10 seconds, rinsed with pure water for 15 seconds, and then shaken and dried.
Subsequently, post-baking was performed on a hot plate at 100 ° C. for 45 seconds.
As a result, in each example, a 1: 1 line and space (LS) pattern having a line width of 50 nm and a pitch of 100 nm was formed.
The optimum exposure dose Eop (mJ / cm ² ; sensitivity) for forming the LS pattern was determined. The results are shown in Tables 25 and 26.

[Evaluation of exposure margin (EL margin)]
In Eop, the exposure amount when the line of the LS pattern is formed within a range of ± 5% (47.5 nm to 52.5 nm) of the target dimension (line width 50 nm) is obtained, and the EL margin (unit: %). The results are shown in Tables 25 and 26.
EL margin (%) = (| E1-E2 | / EOP) × 100
E1: Exposure amount (mJ / cm ² ) when an LS pattern having a line width of 47.5 nm was formed
E2: exposure amount (mJ / cm ² ) when an LS pattern having a line width of 52.5 nm was formed
Note that the larger the value of the EL margin, the smaller the change amount of the pattern size accompanying the change in the exposure amount.

[Evaluation of mask error factor (MEF)]
According to the same procedure as the formation of the resist pattern, in the Eop, a mask pattern targeting a LS pattern with a line width of 50 nm and a pitch of 100 nm and a mask pattern targeting a LS pattern with a line width of 55 nm and a pitch of 100 nm are used. Each LS pattern was formed, and the MEF value was determined from the following equation. The results are shown in Tables 25 and 26.
MEF = | CD55-CD50 | / | MD55-MD50 |
In the above formula, CD50 and CD55 are the actual line widths (nm) of the LS pattern formed using the mask pattern targeting the line widths of 50 nm and 55 m, respectively. MD50 and MD55 are line widths (nm) targeted by the mask pattern, respectively, and MD50 = 50 nm and MD55 = 55 nm.
The closer this MEF value is to 1, the more the resist pattern faithful to the mask pattern is formed.

[LWR (line width roughness) evaluation]
In the LS pattern having a line width of 50 nm and a pitch of 100 nm formed by the Eop, the space width is changed by a length measuring SEM (scanning electron microscope, acceleration voltage 300 V, product name: S-9380, manufactured by Hitachi High-Technologies Corporation). 400 points were measured in the longitudinal direction, and a triple value (3s) of the standard deviation (s) was obtained from the result, and a value averaged for 3s at 400 points was calculated as a scale indicating LWR. The results are shown in Tables 25 and 26.
A smaller value of 3s means that the roughness of the line width is smaller, and an LS pattern having a more uniform width is obtained.

[Pattern shape evaluation]
The cross-sectional shape of the pattern formed in the Eop was observed using a scanning electron microscope (trade name: SU-8000, manufactured by Hitachi High-Technology Corporation), and the shape was evaluated according to the following criteria. The results are shown in Tables 25 and 26.
○: The rectangularity is high and good.
Δ: Slightly T-top shape.
X: Tapered shape.

  From the results of Tables 25 and 26, the resist compositions of Examples 22 to 42 according to the present invention have lithography characteristics (EL margin, MEF, LWR) and pattern shape as compared with the resist compositions of Comparative Examples 23 to 44. It was confirmed that it was excellent.

Claims (9)

Having an anion moiety that generates an acid upon exposure at least at one end of the main chain; and
A polymer having a structural unit (a0) containing a —SO ₂ -containing cyclic group. The polymer of Claim 1 which has group represented by the following general formula (I-1) at the at least one terminal of the said principal chain.

[Wherein, R ¹ is a hydrocarbon group having 1 to 10 carbon atoms, Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group, and R ¹ and Z are bonded to each other to form a ring. You may do it. X is a divalent linking group, and at least one of —O—C (═O) —, —NH—C (═O) —, and —NH—C (═NH) — It is at the end that contacts Q. p is an integer of 1 to 3. Q is a (p + 1) -valent hydrocarbon group, and Q may be a single bond only when p is 1. R ² is a single bond, an alkylene group which may have a substituent, or an aromatic group which may have a substituent, q is 0 or 1, and r is an integer of 0 to 8. is there. M ⁺ is an organic cation. ] The polymer according to claim 2, which is a radical polymer obtained by radical polymerization using a radical polymerization initiator comprising a compound represented by the following general formula (I).

[Wherein, R ¹ is a hydrocarbon group having 1 to 10 carbon atoms, Z is a hydrocarbon group having 1 to 10 carbon atoms or a cyano group, and R ¹ and Z are bonded to each other to form a ring. You may do it. X is a divalent linking group, and at least one of —O—C (═O) —, —NH—C (═O) —, and —NH—C (═NH) — It is at the end that contacts Q. p is an integer of 1 to 3. Q is a (p + 1) -valent hydrocarbon group, and Q may be a single bond only when p is 1. R ² is a single bond, an alkylene group which may have a substituent, or an aromatic group which may have a substituent, q is 0 or 1, and r is an integer of 0 to 8. is there. M ⁺ is an organic cation. A plurality of R ¹ , Z, X, p, Q, R ² , q, r, and M ⁺ in the formula may be the same or different. ]   The structural unit (a0) is a structural unit derived from an acrylate ester in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent. The polymer described in 1. The polymer according to claim 4, wherein the structural unit (a0) is a structural unit represented by the following general formula (a0-0-11) or general formula (a0-0-12).

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms, R ⁴⁰ is —O— or —NH—, and R ²⁰ is divalent. A ′ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, z is an integer of 0 to 2, and R ⁶ is An alkyl group, an alkoxy group, a halogenated alkyl group, a hydroxyl group, —COOR ″, —OC (═O) R ″, a hydroxyalkyl group or a cyano group, and R ″ is a hydrogen atom or an alkyl group.]   Furthermore, the polymer as described in any one of Claims 1-5 which has a structural unit (a1) containing the acid-decomposable group which polarity increases by the effect | action of an acid.   The resist composition containing the polymer as described in any one of Claims 1-6. A base material component (A) that changes its solubility in a developer by the action of an acid and generates an acid upon exposure; and
A resist composition containing an acid generator component (B) that generates an acid upon exposure (excluding the base material component (A)),
The resist composition in which the base material component (A) contains the polymer according to claim 6.   A resist comprising a step of forming a resist film on the support using the resist composition according to claim 7 or 8, a step of exposing the resist film, and a step of developing the resist film to form a resist pattern. Pattern forming method.