JP2010102333A - Positive resist composition, method of forming resist pattern, and polymeric compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel polymeric compound useful as a base component of a positive resist composition, a compound useful as a monomer of the polymeric compound, a positive resist composition including the polymeric compound, and a method of forming a resist pattern using the positive resist composition. <P>SOLUTION: The positive resist composition contains a base component (A) which exhibits increased solubility in an alkali developing solution under action of acid and an acid-generator component (B) which generates acid upon exposure, wherein the base component (A) contains a polymeric compound (A1) including: a (meth)acrylate unit (a0) having an ester group having a norbornyl lactone structure in a side chain; and a structural unit (a1) derived from a (meth)acrylate ester containing an acid dissociable, dissolution inhibiting group. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a novel polymer compound that can be used as a base component of a positive resist composition, a positive resist composition containing the polymer compound, and a resist pattern forming method using the positive resist composition.

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

Resist materials are required to have lithography characteristics such as sensitivity to these exposure light sources and resolution capable of reproducing a pattern with fine dimensions.
As a resist material that satisfies such requirements, a chemically amplified resist composition containing a base material component whose solubility in an alkaline developer is changed by the action of an acid and an acid generator that generates an acid upon exposure is used. ing.
For example, as a positive chemically amplified resist composition, a composition containing a resin component (base resin) whose solubility in an alkaline developer is increased by the action of an acid and an acid generator component is generally used. Yes. When such a resist film formed using the resist composition is selectively exposed at the time of resist pattern formation, an acid is generated from the acid generator in the exposed portion, and the alkali developer of the resin component is generated by the action of the acid. As a result, the exposed area becomes soluble in an alkaline developer.
Currently, as a resist base resin used in ArF excimer laser lithography and the like, a resin (acrylic resin) having a structural unit derived from (meth) acrylic acid ester in its main chain because of its excellent transparency near 193 nm Etc. are generally used (see, for example, Patent Documents 1 and 2). Here, “(meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position. “(Meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position. “(Meth) acrylate” means one or both of an acrylate having a hydrogen atom bonded to the α-position and a methacrylate having a methyl group bonded to the α-position.
At present, as a base resin for a chemically amplified resist, a resin containing a plurality of structural units is used in order to improve lithography properties and the like. For example, in the case of the positive type, it usually contains a structural unit having an acid dissociable, dissolution inhibiting group that is dissociated by the action of an acid generated from an acid generator, and further has a structural unit having a polar group such as a hydroxyl group, a lactone structure. The thing containing the structural unit which has is used. Among these, the structural unit having a lactone structure is generally considered to contribute to the improvement of lithography properties by improving the adhesion of the resist film to the substrate and the affinity with an alkali developer.

JP 2003-241385 A JP 2006-016379 A

In the future, there are demands for new materials that can be used for lithography applications, as further progress in lithography technology and expansion of application fields are expected. For example, as the pattern becomes finer, the resist material is also required to improve various lithography properties such as resolution.
One such lithography characteristic is a pattern shape. In a conventional resist composition, the resist pattern is formed as a result of an increase or decrease in the amount of light applied to the exposed portion due to changes in the mask size (hole diameter in the hole pattern or line width in the line and space pattern) used in forming the resist pattern. The shape of the resist pattern may be destroyed. Such a problem is likely to occur when a fine pattern is formed at a narrow pitch. For example, when a hole pattern having a hole diameter of about 100 nm or less is formed, there is a possibility that the roundness of the hole may be low, and the improvement is improved. Desired.
The present invention has been made in view of the above circumstances, and includes a novel polymer compound useful as a base component of a positive resist composition, a compound useful as a monomer of the polymer compound, and the polymer compound. It is an object of the present invention to provide a positive resist composition to be contained, and a resist pattern forming method using the positive resist composition.

In order to achieve the above object, the present invention employs the following configuration.
That is, the first aspect of the present invention is a positive type containing a base component (A) whose solubility in an alkaline developer is increased by the action of an acid, and an acid generator component (B) that generates an acid upon exposure. A resist composition comprising:
The base material component (A) has a structural unit (a0) represented by the following general formula (a0-1) and a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group. A positive resist composition comprising a polymer compound (A1).

［式中、Ｒ^１は水素原子、低級アルキル基またはハロゲン化低級アルキル基であり、Ｒ^２は２価の連結基であり、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、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る。］

[Wherein, R ¹ is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ² is a divalent linking group, and R ′ is independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. , An alkoxy group having 1 to 5 carbon atoms or —COOR ″, R ″ is a hydrogen atom or an alkyl group, and 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.]

According to a second aspect of the present invention, there is provided a step of forming a resist film on a support using the positive resist composition of the first aspect, a step of exposing the resist film, and an alkali development of the resist film. And a resist pattern forming method including a step of forming a resist pattern.
The third aspect of the present invention has a structural unit (a0) represented by the following general formula (a0-1) and a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group. It is a polymer compound.

［式中、Ｒ^１は水素原子、低級アルキル基またはハロゲン化低級アルキル基であり、Ｒ^２は２価の連結基であり、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、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る。］

[Wherein, R ¹ is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ² is a divalent linking group, and R ′ is independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. , An alkoxy group having 1 to 5 carbon atoms or —COOR ″, R ″ is a hydrogen atom or an alkyl group, and 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.]

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

  According to the present invention, a novel polymer compound that can be used as a base component of a positive resist composition, a positive resist composition containing the polymer compound, and a resist pattern forming method using the positive resist composition Can provide.

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

<(A) component>
[Polymer Compound (A1)]
The polymer compound (A1) (hereinafter referred to as component (A1)) is derived from the structural unit (a0) represented by the general formula (a0-1) and an acrylate ester containing an acid dissociable, dissolution inhibiting group. The structural unit (a1).
In addition to the structural units (a0) and (a1), the component (A1) is a structural unit derived from an acrylate ester containing a lactone-containing cyclic group that does not correspond to the structural unit (a0). It is preferable to have.
In addition to the structural units (a0) and (a1), or in addition to the structural units (a0), (a1) and (a2), the component (A1) further contains a polar group-containing aliphatic hydrocarbon group. It is preferable to have a structural unit (a3) derived from an acrylic ester contained.

(Structural unit (a0))
In formula (a0-1), R ¹ represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group.
The lower alkyl group for R ¹ is preferably a linear or branched alkyl group having 1 to 5 carbon atoms, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group. Group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like.
The halogenated lower alkyl group for R ¹ is a group in which part or all of the hydrogen atoms of the lower 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 ¹ is preferably a hydrogen atom, a lower alkyl group or a fluorinated lower alkyl group, and most preferably a hydrogen atom or a methyl group from the viewpoint of industrial availability.

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

More specifically, examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, and the like.
The linear or branched aliphatic hydrocarbon group preferably has 1 to 10 carbon atoms, more preferably 1 to 8, still more preferably 1 to 5, and most preferably 1 to 2.
As the linear aliphatic hydrocarbon group, a linear alkylene group is preferable. Specifically, a methylene group [—CH ₂ —], an ethylene group [— (CH ₂ ) ₂ —], a trimethylene group [ — (CH ₂ ) ₃ —], tetramethylene group [— (CH ₂ ) ₄ —], pentamethylene group [— (CH ₂ ) ₅ —] and the like can be mentioned.
As the branched aliphatic hydrocarbon group, a branched alkylene group is preferred, and specifically, —CH (CH ₃ ) —, —CH (CH ₂ CH ₃ ) —, —C (CH ₃ ). Alkylmethylene groups such as _2- , —C (CH ₃ ) (CH ₂ CH ₃ ) —, —C (CH ₃ ) (CH ₂ CH ₂ CH ₃ ) —, —C (CH ₂ CH ₃ ) 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 -, - 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 lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, and an oxygen atom (= O).

Examples of the aliphatic hydrocarbon group including a ring in the structure include a cyclic aliphatic hydrocarbon group (a group obtained by removing two hydrogen atoms from an aliphatic hydrocarbon ring), and the cyclic aliphatic hydrocarbon group includes the chain described above. And a group that is bonded to the terminal of the chain-like aliphatic hydrocarbon group or intervenes in the middle of the chain-like aliphatic hydrocarbon group.
The cyclic aliphatic hydrocarbon group preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The cyclic aliphatic hydrocarbon group may be a polycyclic group or a monocyclic group. As the monocyclic group, a group in which two hydrogen atoms 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 a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.

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

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

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

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

In the formula (a0-1), A ″ is an alkylene group having 1 to 5 carbon atoms, an oxygen atom, or a sulfur atom that may contain an oxygen atom (—O—) or a sulfur atom (—S—). .
The alkylene group having 1 to 5 carbon atoms in A ″ is preferably a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group.
When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include a group in which —O— or —S— is interposed between the terminal or carbon atoms of the alkylene group, for example, —O—CH _{2. -, - CH 2 -O-CH} 2 -, - S-CH 2 -, - CH 2 -S-CH 2 - , and the like.
A ″ is preferably an alkylene group having 1 to 5 carbon atoms or —O—, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.

In formula (a0-1), R ′ each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or —COOR ″.
The alkyl group for R ′ 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 for R ′ is preferably linear or branched. Specifically, the group couple | bonded with the oxygen atom (-O-) to the alkyl group quoted as the alkyl group in said R 'is mentioned.
In —COOR ″, R ″ represents a hydrogen atom or an alkyl group.
The alkyl group in R ″ may be linear, branched or cyclic, and preferably has 1 to 15 carbon atoms.
When R ″ is a linear or branched alkyl group, the alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and is a methyl group or an ethyl group. It is particularly preferred.
When R ″ is a cyclic alkyl group, the alkyl group preferably has 3 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Is one or more hydrogen atoms from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group More specifically, one or more hydrogens from monocycloalkanes such as cyclopentane and cyclohexane, and polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Examples include groups excluding atoms.
In formula (a0-1), two R ′ may be the same or different.
R ′ is preferably a hydrogen atom or an alkoxy group in view of industrial availability.

  Preferred specific examples of the structural unit (a0) are shown below.

［式中、Ｒ^１およびＡ”はそれぞれ前記と同じであり、Ｒ^２’は直鎖状または分岐鎖状のアルキレン基である。］

[Wherein, R ¹ and A ″ are the same as defined above, and R ² ′ is a linear or branched alkylene group.]

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

As the structural unit (a0), one type may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a0) in the component (A1) depends on the MEF, the shape of the resist pattern to be formed, and the CDU when a resist pattern is formed using the positive resist composition containing the component (A1). Since it is excellent in (in-plane uniformity), LWR (line width roughness), etc., it is preferable that it is 1-60 mol% with respect to all the structural units which comprise (A1) component, and 5-50 mol% is more. Preferably, 10-40 mol% is more preferable.

(Structural unit (a1))
The structural unit (a1) is a structural unit derived from an acrylate ester not containing the structural unit (a0) and containing an acid dissociable, dissolution inhibiting group.
The acid dissociable, dissolution inhibiting group in the structural unit (a1) has an alkali dissolution inhibiting property that makes the entire component (A1) difficult to dissolve in an alkali developer before dissociation, and dissociates with an acid. It increases the solubility of the entire component in an alkaline developer, and those proposed so far as acid dissociable, dissolution inhibiting 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, dissolution inhibiting group such as an alkoxyalkyl group is widely known. . The “(meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position.
Here, the “tertiary alkyl ester” is an ester formed by replacing a hydrogen atom of a carboxy group with a chain or cyclic alkyl group, and the carbonyloxy group (—C (O)). A structure in which the tertiary carbon atom of the chain or cyclic alkyl group is bonded to the terminal oxygen atom of -O-). In this tertiary alkyl ester, when an acid acts, a bond is cut between an oxygen atom and a tertiary carbon atom.
The chain or cyclic alkyl group may have a substituent.
Hereinafter, a group that is acid dissociable by constituting a carboxy group and a tertiary alkyl ester is referred to as a “tertiary alkyl ester type acid dissociable, dissolution inhibiting group” for convenience.

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

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The “aliphatic cyclic group” in the structural unit (a1) may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a lower alkoxy group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.
The basic ring structure excluding the substituent of the “aliphatic cyclic group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated. The “aliphatic cyclic group” is preferably a polycyclic group.
Examples of the aliphatic cyclic group include a group in which one or more hydrogen atoms have been removed from a monocycloalkane which may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group. , Groups obtained by removing one or more hydrogen atoms from a polycycloalkane such as bicycloalkane, tricycloalkane, and tetracycloalkane. More specifically, a group obtained by removing one or more hydrogen atoms from a monocycloalkane such as cyclopentane or cyclohexane or one or more polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane or tetracyclododecane. And a group in which hydrogen atom is removed. Further, a part of carbon atoms constituting the ring of a group obtained by removing one or more hydrogen atoms from these monocycloalkanes or a group obtained by removing one or more hydrogen atoms from polycycloalkane is an etheric oxygen atom (- O-) may be substituted.

Examples of the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group include (i) a group having a tertiary carbon atom on the ring skeleton of a monovalent aliphatic cyclic group; A group having an aliphatic cyclic group and a branched alkylene having a tertiary carbon atom bonded thereto; and the like.
(I) Specific examples of the group having a tertiary carbon atom on the ring skeleton of the monovalent aliphatic cyclic group are represented by the following general formulas (1-1) to (1-9). Groups and the like.
(Ii) Specific examples of the group having a monovalent aliphatic cyclic group and a branched alkylene group having a tertiary carbon atom bonded thereto include, for example, the following general formulas (2-1) to (2-1) And the group represented by (2-6).

［式中、Ｒ^１４はアルキル基であり、ｇは０〜８の整数である。］

^{Wherein, R 14} represents an alkyl group, g is an integer of 0-8. ]

［式中、Ｒ^１５およびＲ^１６は、それぞれ独立してアルキル基である。］

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

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

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

［式中、Ｒ^１’，Ｒ^２’はそれぞれ独立して水素原子または低級アルキル基を表し、ｎは０〜３の整数を表し、Ｙは低級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 a lower alkyl group, n represents an integer of 0 to 3, and Y represents a lower alkyl group or an aliphatic cyclic group. ]

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

［式中、Ｒ^１’、ｎ、Ｙは上記と同じである。］

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

Examples of the lower alkyl group for Y include the same lower alkyl groups as those described above for R ¹ .
The aliphatic cyclic group for Y can be appropriately selected from monocyclic or polycyclic aliphatic cyclic groups conventionally proposed in a number of ArF resists and the like. For example, the above “aliphatic ring” Examples thereof are the same as those in the formula group.

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

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

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

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

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

［式中、Ｒ^１３は水素原子またはメチル基であり、ｇは前記と同じである。］

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

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

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基であり；Ｘ^１は酸解離性溶解抑制基であり；Ｙ^２は２価の連結基であり；Ｘ^２は酸解離性溶解抑制基である。］

[Wherein, R is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; X ¹ is an acid dissociable, dissolution inhibiting group; Y ² is a divalent linking group; X ² is acid dissociable] It is a dissolution inhibiting group. ]

In general formula (a1-0-1), R is the same as R ¹ in formula (a0-1).
X ¹ is not particularly limited as long as it is an acid dissociable, dissolution inhibiting group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable, dissolution inhibiting group and acetal type acid dissociable, dissolution inhibiting group. And tertiary alkyl ester type acid dissociable, dissolution inhibiting groups are preferred.

In general formula (a1-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a1-0-1).
Examples of the divalent linking group for Y ² include the same groups as those described above for R ² in formula (a0-1).
Y ² is preferably the alkylene group, divalent aliphatic cyclic group or divalent linking group containing a hetero atom. Among these, a divalent linking group containing a hetero atom is preferable, and a linear group having an oxygen atom as a hetero atom, for example, a group containing an ester bond is particularly preferable.
Among them, a group represented by the above-described —A—O—B— or —A—C (═O) —O—B— is preferable, and in particular, — (CH ₂ ) _a —C (═O) —O— ( CH _{2) b} - group is particularly desirable.
a is an integer of 1 to 5, preferably 1 or 2, and most preferably 1.
b is an integer of 1 to 5, preferably 1 or 2, and most preferably 1.

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

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

[Wherein, X ′ represents a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, Y represents a lower alkyl group having 1 to 5 carbon atoms, or an aliphatic cyclic group; n represents an integer of 0 to 3] Y ² represents a divalent linking group; R is the same as defined above; R ¹ ′ and R ² ′ each independently represent a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms. ]

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

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

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

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

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

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

［式中、Ｒ、Ｒ^２１はそれぞれ前記と同じであり、ｈは１〜３の整数である。］

[Wherein, R and R ²¹ are the same as defined above, and h is an integer of 1 to 3, respectively. ]

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

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

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

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

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

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

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

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

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

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

［式中、ＲおよびＲ^１４はそれぞれ前記と同じであり、Ｒ^２０は水素原子またはメチル基であり、ａは１〜１０の整数であり、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, R ²⁰ is a hydrogen atom or a methyl group, a is an integer of 1 to 10, b is an integer of 1 to 10, and t is 0. It is an integer of ~ 3. ]

a is preferably an integer of 1 to 5, and particularly preferably 1 or 2.
b is preferably an integer of 1 to 5, and 1 or 2 is particularly preferable.
t is preferably an integer of 1 to 3, and 1 or 2 is particularly preferable.

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

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

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

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

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

(Structural unit (a2))
The structural unit (a2) is a structural unit derived from an acrylate ester containing a lactone-containing cyclic group, which does not correspond to the structural unit (a0).
Here, the lactone-containing cyclic group refers to a cyclic group containing one ring (lactone ring) containing an —O—C (O) — structure. The lactone ring is counted as the first ring. When only the lactone ring is present, it is called a monocyclic group. When it has another ring structure, it is called a polycyclic group regardless of the structure.
When the component (A1) is used for forming a resist film, the lactone cyclic group of the structural unit (a2) increases the adhesion of the resist film to the substrate or has an affinity for a developer containing water. It is effective in raising.
As the structural unit (a2), any unit can be used without any particular limitation.
Specifically, as the lactone-containing monocyclic group, a group 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, a group in which one hydrogen atom has been removed from δ-valerolactone, and the like. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.
More specifically, examples of the structural unit (a2) include structural units represented by general formulas (a2-1) to (a2-5) shown below.

［式中、Ｒ、Ｒ’およびＡ”はそれぞれ前記と同じであり、Ｒ^２９は単結合または２価の連結基であり、ｓ”は０または１〜２の整数であり、ｍは０または１の整数である。］

[Wherein, R, R ′ and A ″ are the same as defined above, R ²⁹ represents a single bond or a divalent linking group, s ″ represents 0 or an integer of 1 to 2, and m represents 0 or It is an integer of 1. ]

R ²⁹ is a single bond or a divalent linking group. Examples of the divalent linking group include the same divalent linking groups as those described above for the R ^2, Among these, an alkylene group, an ester bond (-C (= O) -O-) , or a combination thereof Preferably there is. The alkylene group as the divalent linking group for R ²⁹ is more preferably a linear or branched alkylene group. Specifically, the same linear alkylene groups and branched alkylene groups as those described above for R ² can be used.
s ″ is preferably an integer of 1 to 2.
Specific examples of the structural units represented by the general formulas (a2-1) to (a2-5) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

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

  The proportion of the structural unit (a2) in the component (A1) is such that the resist film formed using the positive resist composition containing the component (A1) adheres to a support such as a substrate, and the developer. From the viewpoint of excellent affinity and the like, it is preferably 1 to 50% by mole, more preferably 5 to 50% by mole, and further more preferably 10 to 45% by mole based on all structural units constituting the component (A1). preferable.

In addition, since the component (A1) is excellent in various lithography properties, the total proportion of the structural unit (a0) and the structural unit (a2) (the structural unit (a0 in the case where the structural unit (a2) is not included). ) Only) is preferably 5 to 70 mol%, more preferably 1 to 70 mol%, and more preferably 10 to 65 mol% with respect to all structural units constituting the component (A1). More preferably, 20 to 65 mol% is most preferable. By setting it as the said range, MEF, CDU, and a pattern shape will become further favorable.
When the component (A1) contains both the structural unit (a0) and the structural unit (a2), the proportion of the structural unit (a0) and the structural unit (a2) in the component (A1) is the structural unit (a0). Is preferably 1 to 40 mol%, more preferably 10 to 35 mol%, most preferably 15 to 30 mol%, and the structural unit (a2) is preferably 1 to 45 mol%, more preferably 10 to 45 mol%, 20 to 45 mol% is most preferable.

(Structural unit (a3))
The structural unit (a3) is a structural unit derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group.
When the component (A1) has the structural unit (a3), the hydrophilicity of the component (A) is increased, the affinity with the developer is increased, the alkali solubility in the exposed area is improved, and the resolution is improved. Contributes to improvement.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a fluorinated alcohol group (a hydroxyalkyl group in which a part of the hydrogen atoms of the 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 polycyclic aliphatic hydrocarbon group (polycyclic group). It is done. As the polycyclic group, for example, a resin for a resist composition for ArF excimer laser can be appropriately selected from among many proposed ones. The polycyclic group preferably has 7 to 30 carbon atoms.
Among these, a structural unit derived from an acrylate ester containing an aliphatic polycyclic group containing a hydroxyl group, a cyano group, a carboxy group, or a fluorinated alcohol group 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, a structural unit represented by the following formula (a3-1), a structural unit represented by (a3-2), (a3-3) ) Is preferable.

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

(Wherein R is the same as 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.
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. These preferably have a 2-norbornyl group or a 3-norbornyl group 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.

As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.
The proportion of the structural unit (a3) in the component (A1) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, based on all structural units constituting the component (A1). More preferred is ˜25 mol%.

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

（式中、Ｒは前記と同じである。）

(In the formula, R is as defined above.)

  When the structural unit (a4) is contained in the component (A1), the proportion of the structural unit (a4) is preferably 1 to 30 mol% with respect to the total of all the structural units constituting the component (A1). -20 mol% is more preferable.

The component (A1) is preferably a copolymer having the structural units (a0) and (a1). Examples of such a copolymer include a copolymer composed of the structural units (a0) and (a1), a copolymer composed of the structural units (a0), (a1) and (a3), a structural unit (a0), Examples thereof include a copolymer comprising (a1) and (a2), a copolymer comprising the structural units (a0), (a1), (a2) and (a3).
In the present invention, in particular, these copolymers are represented by the structural unit represented by the general formula (a1-0-11), the general formula (a1-0-12) as the structural unit (a1). And at least one selected from the group consisting of structural units represented by general formula (a1-0-2).
Further, as described above, the copolymer preferably has at least two structural units (a1), and at least one of the at least two structural units is represented by the general formula (a1-0-11). A structural unit selected from the group consisting of a structural unit represented by the general formula (a1-0-12) and a structural unit represented by the general formula (a1-0-2) preferable.

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

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

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

［式（Ｉ）中、Ｒ^１、Ｒ^２、Ｒ’およびＡ”はそれぞれ前記と同じである。］

[In formula (I), R ¹ , R ² , R ′ and A ″ are the same as defined above.]

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

［式（Ｉ）中、Ｒ^１、Ｒ^２、Ｒ’およびＡ”はそれぞれ前記と同じである。］

[In formula (I), R ¹ , R ² , R ′ and A ″ are the same as defined above.]

In the resist composition of the present invention, as the component (A), a base material component (hereinafter referred to as the component (A2)) that does not correspond to the component (A1) and whose solubility in an alkaline developer is increased by the action of an acid. You may contain.
The component (A2) is not particularly limited, and many conventionally known base components for chemically amplified positive resist compositions (for example, for ArF excimer laser, for KrF excimer laser (preferably ArF) A base resin such as for excimer laser) may be arbitrarily selected and used. For example, the base resin for ArF excimer laser includes a resin having the structural unit (a1) as an essential structural unit and optionally further having the structural units (a2) to (a4).
(A2) A component may be used individually by 1 type and may be used in combination of 2 or more type.

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

<(B) component>
The component (B) is not particularly limited, and those that have been proposed as acid generators for chemically amplified resists can be used. Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, and poly (bissulfonyl) diazomethanes. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.
As the onium salt acid generator, for example, a compound represented by the following general formula (b-1) or (b-2) can be used.

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

[Wherein, R ¹ ″ to R ³ ″ and R ⁵ ″ to R ⁶ ″ each independently represents an aryl group or an alkyl group; 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 alkyl group, a halogenated alkyl group, an aryl group or an alkenyl which may have a substituent; Represents at least one of R ¹ ″ to R ³ ″ represents an aryl group, and at least one of R ⁵ ″ to R ⁶ ″ represents an aryl group.]

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

The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and is, for example, an aryl group having 6 to 20 carbon atoms, in which part or all of the hydrogen atoms are alkyl or alkoxy. 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, ethyl group, propyl group, n-butyl group, or tert-butyl group. Is most preferred.
As the alkoxy group that may be substituted for the hydrogen atom of the aryl group, an alkoxy group having 1 to 5 carbon atoms is preferable, and a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, A tert-butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
The halogen atom that may be substituted 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 decanyl 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 (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, a 3 to 10 membered ring including the sulfur atom is formed. It is preferable that a 5- to 7-membered ring is formed.
When any two of R ¹ ″ to R ³ ″ in formula (b-1) are bonded to each other to form a ring together with the sulfur atom in the formula, the remaining one may be an aryl group preferable. Examples of the aryl group are the same as the aryl groups of R ¹ ″ to R ³ ″.

Preferred examples of the cation moiety of the compound represented by the formula (b-1) include the following formulas (I-1-1) to (I-1-13) and (I-2-1) to (I- The cation part represented by 2-2) is mentioned. Among these, those having a triphenylmethane skeleton such as a cation moiety represented by formulas (I-1-1) to (I-1-13) are preferable. Moreover, what substituted a part or all of the phenyl group in the cation part which has a triphenylmethane skeleton with the naphthyl group which may have a substituent is mentioned as a preferable thing.
In the following formulas (I-2-1) to (I-2-2), R ⁹ and R ¹⁰ are each independently a phenyl group, a naphthyl group, or a carbon number of 1 to 5 which may have a substituent. An alkyl group, an alkoxy group, and a hydroxyl group.
u is an integer of 1 to 3, and 1 or 2 is most preferable.

R 4 ^"is an optionally substituted alkyl group, a halogenated alkyl group, an aryl group or an alkenyl group.
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 hetero atom, an alkyl group which may have a substituent, a formula: XQ ^1- [where Q ¹ is a divalent linking group containing an oxygen atom. Yes, X is a hydrocarbon group having 3 to 30 carbon atoms which may have a substituent. ] Etc. which are represented by these.
Examples of the halogen atom include those similar to those exemplified as the halogen atom in the halogenated alkyl group in R ⁴ ″.
Examples of the hetero atom include an oxygen atom, a nitrogen atom, and a sulfur atom.
Examples of the alkyl group include the same groups as those described above as the “alkyl group optionally having substituent (s)” for R ⁴ ″.

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

In the group represented by XQ ^1- , the hydrocarbon group of X may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.
The aromatic hydrocarbon group is a hydrocarbon group having an aromatic ring. The aromatic hydrocarbon group preferably has 3 to 30 carbon atoms, more preferably 5 to 30, more preferably 5 to 20, particularly 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. Examples include aryl groups such as aryl group, benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc., from which one is removed. The number of carbon atoms of the alkyl chain in the arylalkyl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.
The aromatic hydrocarbon group may have a substituent. For example, a part of carbon atoms constituting the aromatic ring of the aromatic hydrocarbon group may be substituted with a hetero atom, and the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group is substituted with the substituent. May be.
Examples of the former include heteroaryl groups in which some of the carbon atoms constituting the ring of the aryl group are substituted with heteroatoms such as oxygen atoms, sulfur atoms and 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 may be a saturated aliphatic hydrocarbon group or an unsaturated aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear, branched or cyclic.
In X, the aliphatic hydrocarbon group may have a part of the carbon atoms constituting the aliphatic hydrocarbon group substituted by a substituent containing a hetero atom, and the hydrogen atom constituting the aliphatic hydrocarbon group May be substituted with a substituent containing a hetero atom.
The “heteroatom” in X is not particularly limited as long as it is an atom other than a carbon atom and a hydrogen atom, and examples thereof include a halogen atom, an oxygen atom, a sulfur atom, and a nitrogen atom. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom.
The substituent containing a hetero atom may be composed only of the hetero atom, or may be a group containing a group or atom other than the hetero atom.
Specific examples of the substituent for substituting a part of carbon atoms include, for example, —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O. -, - C (= O) -NH -, - NH- (H 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. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent that substitutes part or all of the hydrogen atoms include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and a cyano group.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.

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

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

The aliphatic cyclic group may be a monocyclic group or a polycyclic group. The number of carbon atoms is preferably 3 to 30, more preferably 5 to 30, further preferably 5 to 20, particularly preferably 6 to 15, and most preferably 6 to 12.
Specifically, for example, a group in which one or more hydrogen atoms 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 one or more hydrogen atoms from the polycycloalkane are substituted. Excluded groups are preferred, and groups obtained by removing one or more hydrogen atoms from adamantane are most preferred.
When the aliphatic cyclic group includes a substituent containing a hetero atom in the ring structure, examples of the substituent containing a hetero atom include —O—, —C (═O) —O—, —S—. , —S (═O) ₂ — and —S (═O) ₂ —O— are preferable. Specific examples of the aliphatic cyclic group include the following formulas (L1) to (L5), (S1) to (S4), and the like.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

[Wherein X ″ represents an alkylene group having 2 to 6 carbon atoms in which at least one hydrogen atom is substituted with a fluorine atom; Y ″ and Z ″ each independently represent at least one hydrogen atom as a fluorine atom; Represents an alkyl group having 1 to 10 carbon atoms 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, 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 ″, the strength of the acid increases as the number of hydrogen atoms substituted with fluorine atoms increases, and high-energy light or electron beam of 200 nm or less The ratio of fluorine atoms in the alkylene group or alkyl group, that is, the fluorination rate is preferably 70 to 100%, more preferably 90 to 100%, and most preferably all. Are a perfluoroalkylene group or a perfluoroalkyl group in which a hydrogen atom is substituted with a fluorine atom.

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

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

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

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

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

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

（式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。）

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

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

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

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

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

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

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

In the general formula (B-2), alkyl or halogenated alkyl group having no substituent group for R ³³ preferably has 1 to 10 carbon atoms, 1 to 8 carbon atoms, more preferably, carbon 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 having no substituent as R ³⁵ described above.
p ″ is preferably 2.

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Also, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [chemical formula 18] to [chemical formula 19]), WO 2004 / 074242A2 (pages 65 to 85). The oxime sulfonate acid generators disclosed in Examples 1 to 40) of No. 1 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

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

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

<Optional component>
The positive resist composition of the present invention may further contain a nitrogen-containing organic compound (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 component (B) by exposure, and a wide variety of components have already been proposed. Therefore, any known one may be used. As the component (D), amines such as aliphatic amines and aromatic amines are preferable, and among them, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are preferable. Here, the aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 20 carbon atoms.
Examples of the aliphatic amine include an amine (alkylamine 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 20 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-hexylamine, tri-n-pentylamine , Tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine, and the like; diethanolamine, triethanolamine, diisopropanolamine Triisopropanolamine, di -n- octanol amine, tri -n- octanol amine, stearyl diethanolamine, alkyl alcohol amines such as lauryl diethanolamine. Among these, trialkylamine and / or alkyl alcohol amine are preferable.
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} ethylamine and the like.
Aromatic amines include aniline, 1,8-naphthalenediamine, pyridine, 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, diphenylamine, triphenylamine, tribenzylamine, and the like.
These may be used alone or in combination of two or more.
(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.

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

[(F) component]
The positive resist composition of the present invention may contain a fluorine-containing polymer compound (F) (hereinafter referred to as “component (F)”). With the component (F), the hydrophilicity / hydrophobicity of the resist film surface can be adjusted without impairing the lithography properties.
For example, when the component (F) is blended, the hydrophobicity of the resist film surface at the time of exposure increases, and it becomes suitable for immersion exposure.
In addition, when a component having a base dissociable group, which will be described later, is blended as the component (F), the component (F) has a property of increasing hydrophilicity by the action of an alkali developer. At the time of development, the surface has hydrophilic properties.
In addition, when a component having an acid dissociable group, which will be described later, is blended as the component (F), the component (F) has a property of increasing hydrophilicity by the action of an acid generated from the component (B) by exposure. When exposure and PEB are performed on the resist film to be formed, the resist film has a property of increasing the hydrophilicity of the exposed portion surface.
When the component (F) is blended, the component (A) preferably does not contain a fluorine atom.

  In the present invention, the component (F) preferably has a structural unit (f1) represented by the following general formula (f1-1).

［式（ｆ１−１）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；Ｑ^０は単結合又は２価の連結基であり、Ｒ^７０はフッ素原子を有する有機基である。複数のＲはそれぞれ同じであっても異なっていてもよい。］

[In the formula (f1-1), R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; Q ⁰ is a single bond or a divalent linking group. , R ⁷⁰ is an organic group having a fluorine atom. A plurality of R may be the same or different. ]

(Structural unit (f1))
In the general formula (f1-1), examples of R include those similar to R in the general formula (a0-1), and a hydrogen atom or a methyl group is preferable.
In the general formula (f1-1), Q ⁰ is a single bond or a divalent linking group.
Examples of the divalent linking group for Q ^0, for example, the same as ^{R 2} in the general formula (a0-1) can be given. Among them, preferred are a divalent hydrocarbon group which may have a substituent and a divalent linking group containing a hetero atom.
The divalent hydrocarbon group which may have a substituent is preferably a linear, branched or cyclic divalent aliphatic hydrocarbon group or divalent aromatic hydrocarbon group. A group, ethylene group, —CH (CH ₃ ) —, a group obtained by further removing one hydrogen atom from a tetracyclododecyl group, and an aromatic hydrocarbon group obtained by further removing one hydrogen atom from a phenyl group are particularly preferred.
Q ⁰ is preferably a divalent linking group containing a single bond or a hetero atom, and a single bond or a divalent non-hydrocarbon group containing a hetero atom and a divalent aliphatic hydrocarbon group among the above. The combination of is particularly preferable.

In the general formula (f1-1), R ⁷⁰ is an organic group that may have a fluorine atom. However, if R ⁷⁰ has no fluorine atom, Q ⁰ is assumed to have a fluorine atom.
Here, the “organic group having a fluorine atom” refers to a group in which part or all of the hydrogen atoms in the organic group are substituted with fluorine atoms.
Preferred examples of the organic group that may have a fluorine atom for R ⁷⁰ include a hydrocarbon group that may have a fluorine atom.
The hydrocarbon group which may have a fluorine atom may be linear, branched or cyclic.
In R ^70, it preferably has a carbon number of 1 to 20, more preferably 1 to 15 carbon atoms, 1 to 10 carbon atoms are particularly preferred.
Further, in the organic group having a fluorine atom of R ⁷⁰ , 25% or more of hydrogen atoms in the organic group are preferably fluorinated, more preferably 50% or more are fluorinated, and 60% or more. It is particularly preferable that is fluorinated since the hydrophobicity of the resist film during immersion exposure is increased.
R ⁷⁰ is preferably a group other than a base dissociable group, an acid dissociable group, a base dissociable group, and an acid dissociable group.

The base dissociable group is a group that exhibits decomposability by the action of an alkali developer (—O—R ⁷⁰ dissociates). “Degradable with respect to alkali developer” means that the developer is decomposed by the action of the alkali developer (preferably, decomposed by the action of an aqueous 2.38 mass% tetramethylammonium hydroxide (TMAH) solution at 23 ° C.) This means that the solubility in an alkali developer is increased. This is because the ester bond [—C (═O) —O—R ⁷⁰ ] is decomposed (hydrolyzed) by the action of a base (alkaline developer) to produce a hydrophilic group [—C (═O) —OH]. This is because (-O-R ⁷⁰ is dissociated).
Preferred examples of the base dissociable group include a fluorinated hydrocarbon group that may or may not have a substituent. Of these, a fluorinated saturated hydrocarbon group or a fluorinated unsaturated hydrocarbon group is preferable, and a fluorinated saturated hydrocarbon group is particularly preferable.
R ⁷⁰ may be linear, branched or cyclic, and is preferably linear or branched.
In R ^70, it preferably has a carbon number of 1 to 20, more preferably 1 to 15 carbon atoms, particularly preferably 1 to 10 carbon atoms, 1 to 5 is most preferred.
The organic group having a fluorine atom in R ^70, it is preferable that 25% or more of the hydrogen atoms in the organic groups are fluorinated, more preferably 50% or more is fluorinated, a fluorine content of at least 60% It is particularly preferred that the resist film is highly hydrophobic because the hydrophobicity of the resist film during immersion exposure increases.

The acid dissociable group is a group that dissociates with an acid and increases the solubility in an alkali developer. The acid dissociable group will be described in detail later. When the acid dissociable group does not contain a fluorine atom, Q ⁰ has a fluorine atom.
The group other than the acid dissociable group and the base dissociable group is, for example, a linear, branched or cyclic alkyl group having 3 to 15 carbon atoms (however, a group having a tertiary carbon atom is excluded). In this case, Q ⁰ has a fluorine atom.

-Acid-dissociable group The acid-dissociable group of R ⁷⁰ is not particularly limited as long as it is an organic group that can be dissociated by the action of an acid. Cyclic or chain-like tertiary alkyl ester type acid dissociation An acetal type acid dissociable group such as an alkoxyalkyl group. Among these, R ⁷⁰ is preferably a tertiary alkyl ester type acid dissociable group, and more preferably a structural unit represented by the following general formula (IV-1).

［式（ＩＶ−１）中、複数のＲ^２０１はそれぞれ同じであっても異なっていてもよく、少なくとも１つは炭素数１〜４の直鎖状もしくは分岐鎖状のアルキル基であり；残りの２つのＲ^２０１は、それぞれ独立して炭素数１〜４の直鎖状もしくは分岐鎖状のアルキル基、または炭素数４〜２０の１価の脂肪族環式基であるか、あるいは、前記残りの２つのＲ^２０１は相互に結合して、それぞれが結合している炭素原子と共に炭素数４〜２０の２価の脂肪族環式基を形成している。］

[In the formula (IV-1), a plurality of R ²⁰¹ may be the same or different, and at least one is a linear or branched alkyl group having 1 to 4 carbon atoms; two of R ²⁰¹ of are either each independently represents a linear or branched alkyl group having 1 to 4 carbon atoms or a monovalent aliphatic cyclic group having 4 to 20 carbon atoms, or wherein The remaining two R ²⁰¹ are bonded to each other to form a divalent aliphatic cyclic group having 4 to 20 carbon atoms together with the carbon atom to which each of R ²⁰¹ is bonded. ]

In the general formula (IV-1), examples of the aliphatic cyclic group represented by R ²⁰¹ include one or more hydrogen atoms from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane. Excluded groups and the like. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. More specifically, a cyclopentyl group, a cyclohexyl group, a norbornyl group, an adamantyl group, and the like can be given.
Examples of the linear or branched alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group.

As the acid dissociable group represented by the general formula (IV-1), a plurality of R ²⁰¹ are each independently a linear or branched alkyl group having 1 to 4 carbon atoms. Examples thereof include a butyl group, a tert-pentyl group, and a tert-hexyl group.

As the acid dissociable group represented by the general formula (IV-1), at least one of the plurality of R ^{201 is} a linear or branched alkyl group having 1 to 4 carbon atoms, and the remaining two R ²⁰¹ Are each independently a linear or branched alkyl group having 1 to 4 carbon atoms or a monovalent aliphatic cyclic group having 4 to 20 carbon atoms, such as 1- (1-adamantyl) ) -1-methylethyl group, 1- (1-adamantyl) -1-methylpropyl group, 1- (1-adamantyl) -1-methylbutyl group, 1- (1-adamantyl) -1-methylpentyl group; 1 -(1-cyclopentyl) -1-methylethyl group, 1- (1-cyclopentyl) -1-methylpropyl group, 1- (1-cyclopentyl) -1-methylbutyl group, 1- (1-cyclopentyl) -1- Methylpentyl 1- (1-cyclohexyl) -1-methylethyl group, 1- (1-cyclohexyl) -1-methylpropyl group, 1- (1-cyclohexyl) -1-methylbutyl group, 1- (1-cyclohexyl)- 1-methylpentyl group, etc. are mentioned.

As the acid dissociable group represented by the general formula (IV-1), among the plurality of R ²⁰¹ , one R ²⁰¹ is a linear or branched alkyl group having 1 to 4 carbon atoms, Examples of the group in which R ²⁰¹ is bonded to each other to form a divalent aliphatic cyclic group having 4 to 20 carbon atoms together with the carbon atom to which each is bonded include a 2-methyl-2-adamantyl group, 2-alkyl-2-adamantyl group such as 2-ethyl-2-adamantyl group, 1-methyl-1-cyclopentyl group, 1-ethyl-1-cyclopentyl group, 1-methyl-1-cyclohexyl group, 1-ethyl 1-alkyl-1-cycloalkyl groups such as a -1-cyclohexyl group.
Among these, as the acid dissociable group represented by the general formula (IV-1), among the plurality of R ²⁰¹ , one R ²⁰¹ is a linear or branched alkyl group having 1 to 4 carbon atoms. In which two R ²⁰¹ 's are bonded to each other to form a divalent aliphatic cyclic group having 4 to 20 carbon atoms together with the carbon atoms to which they are bonded, particularly 2-methyl A 2-adamantyl group is preferred.

Moreover, as long as the group represented by general formula (IV-1) can function as an acid dissociable group, each R ²⁰¹ may have a substituent. Examples of the substituent include a halogen atom such as a fluorine atom.

Below, the suitable specific example of a structural unit (f1) is illustrated.
Hereinafter, the case where R ⁷⁰ in the general formula (f1-1) is a “base dissociable group” is referred to as a structural unit (f11), and the case where R ⁷⁰ is an “acid dissociable group” is referred to as a structural unit (f12). That's it.

(Structural unit (f11))
Preferable specific examples of the structural unit (f11) include structural units represented by the following general formula (f11-1) or formula (f11-2).

［式中、Ｒはそれぞれ独立して水素原子、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；Ｚは二価の有機基であり、Ａ_ａｒｙｌは置換基を有していてもよい芳香族環式基であり、Ｘ_０１は単結合又は二価の連結基であり；Ｒ^７１は、それぞれ独立して、塩基解離性基である。ただし、Ｒ^７１がフッ素原子を有さない場合、（ｆ１１−１）においてはＺが、（ｆ１１−２）においてはＡ_ａｒｙｌ、またはＸ_０１がフッ素原子を有するものとする。］

[Wherein, each R is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; Z is a divalent organic group, and A _aryl is a substituted group. an aromatic cyclic group which may have a group, X ₀₁ is a single bond or a divalent linking group; R ⁷¹ is independently a basic dissociable group. ^{However, if R 71} has no fluorine atom, Z is in the (F11-1), assumed to have the _{A aryl} or _{X 01} is a fluorine atom, in (f11-2). ]

In the general formula (f11-1) or (f11-2), R is the same as described above, and more preferably a hydrogen atom or a methyl group.
The base dissociable group for R ⁷¹ is the same as described above, more preferably an alkyl group having 1 to 2 carbon atoms or a fluorinated hydrocarbon group having 1 to 5 carbon atoms, a methyl group, —CH ₂ —CF _{3. , -CH 2 -CF 2 -CF 3,} -CH (CF 3) 2, and most preferably _{-CH 2 -CH 2 -CF 2 -CF 2} -CF 2 -CF 3. When R ⁷¹ is a methyl group, an ethyl group, or a fluorinated hydrocarbon group, —O—R ⁷¹ in the formula becomes a base dissociable group that is dissociated by the action of an alkali developer.

In the general formula (f11-1), Z is a divalent organic group.
Preferred examples of Z include the above-described hydrocarbon groups that may have a substituent, groups containing heteroatoms, and the like.

In the general formula (f11-2), A _aryl represents an aromatic cyclic group which may have a substituent. Specific examples of A _aryl include a group obtained by removing two hydrogen atoms from an aromatic hydrocarbon ring which may have a substituent.
The ring skeleton of the aromatic cyclic group for A _aryl, preferably has a carbon number of 6 to 15, for example, a benzene ring, a naphthalene ring, a phenanthrene ring, anthracene ring and the like. Among these, a benzene ring or a naphthalene ring is particularly preferable.
In A _aryl , examples of the substituent that the aromatic cyclic group may have include a halogen atom, an alkyl group, an alkoxy group, a halogenated alkyl group having 1 to 5 carbon atoms, and an oxygen atom (═O). Can be mentioned. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom. The substituent that the aromatic cyclic group of A _aryl may have is preferably a fluorine atom.
The aromatic cyclic group of A _aryl may have no substituent, may have a substituent, and preferably has no substituent.
In A _aryl , when the aromatic cyclic group has a substituent, the number of substituents may be one, two or more, and one or two. Is preferable, and one is more preferable.

In the general formula _{(f11-2), X 01} is a single bond or a divalent linking group. Examples of the divalent linking group include an alkylene group having 1 to 10 carbon atoms, —O—, —C (═O) —, —C (═O) —O—, and a carbonate bond (—O—C (═O). -O-), -NH-C (= O)-, or a combination thereof may be mentioned, and a combination of -O- and an alkylene group having 1 to 12 carbon atoms is most preferable.
Examples of the alkylene group having 1 to 12 carbon atoms include linear, branched or cyclic alkylene groups, linear or branched alkylene groups having 1 to 5 carbon atoms, and 4 to 12 carbon atoms. A cyclic alkylene group is preferred.
X ₀₁ is preferably a single bond, — (R ⁷⁷ ) _a0 —O— [C (═O)] _b0 —R ⁷⁸ —, or —C (═O) —O—R ⁷⁹ —.
R ⁷⁷ , R ⁷⁸ , and R ⁷⁹ are each independently a linear, branched or cyclic alkylene group having 1 to 10 carbon atoms, and a linear or branched alkylene group having 1 to 5 carbon atoms. A cyclic alkylene group having 4 to 10 carbon atoms is preferred.
a0 is 0 or an integer of 1 to 5.
b0 is an integer of 0 or 1.

  Preferred examples of the structural unit (f11) include those represented by the following general formulas (f11-1-1) to (f11-1-5) or (f11-2-1) to (f11-2-4). The structural unit is given.

In general formulas (f11-1-1) to (f11-1-5) or (f11-2-1) to (f11-2-4), R and R ⁷¹ are the same as defined above; R ⁸¹ and ^{R 82} are each independently a hydrogen atom, a fluorine atom, an alkyl group having 1 to 5 carbon atoms, represents a fluorinated alkyl group of 1 to 5 carbon atoms; in the case of a1 is 2 or more, plural ^{R 81} and R ⁸² may be the same or different, a1 to a3, a5, a7, a9 and a11 to a13 each independently represent an integer of 1 to 5; a4, a6, a8 And a10 each independently represents an integer of 0 or 1 to 5; b1 to b5 are each independently an integer of 0 or 1;
R ⁸⁰ is a substituent, e represents an integer of 0 to 2; A ₁ is a cyclic alkylene group having 4 to 20 carbon atoms.

In General Formula (f11-1-1), a1 is preferably 1 to 3, and more preferably 1 or 2.
In the general formula (f11-1-2), a2 and a3 are each independently preferably 1 to 3, and more preferably 1 or 2. b1 is 0 or 1.
In the general formula (f11-1-3), a4 is preferably 0 or 1 to 3, more preferably 0 or 1 to 2, and most preferably 0 or 1. a5 is preferably 1 to 3, and more preferably 1 or 2. Examples of the substituent for R ⁸⁰ include a halogen atom, a lower alkyl group, an alkoxy group having 1 to 5 carbon atoms, a halogenated lower alkyl group, and an oxygen atom (═O). Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom. e is preferably 0 or 1, and particularly preferably 0 from an industrial viewpoint. b2 is preferably 0.
In general formula (f11-1-4), a6 is preferably 0 or 1 to 3, more preferably 0 or 1 to 2, and most preferably 0 or 1. a7 is preferably 1 to 3, and more preferably 1 or 2. b3 is preferably 0. R ⁸⁰ and e are the same as defined above.
In the general formula (f11-1-5), A ₁ is a cyclic alkylene group having 4 to 20 carbon atoms, preferably a cyclic alkylene group having 5 to 15 carbon atoms, and a cyclic alkylene group having 6 to 12 carbon atoms. Groups are more preferred. Specific examples include those exemplified in the “cyclic aliphatic hydrocarbon group” in the hydrocarbon group which may have a substituent described above.
In the general formula (f11-2-1), a8 is preferably 0 or 1 to 3, more preferably 0 or 1 to 2, and most preferably 0 or 1. a9 is preferably 1 to 3, and more preferably 1 or 2. b4 is preferably 0. R ⁸⁰ and e are the same as defined above.
In the general formula (f11-2-2), a10 is preferably 0 or 1 to 3, more preferably 0 or 1 to 2, and most preferably 0 or 1. a11 is preferably 1 to 3, and more preferably 1 or 2. b5 is preferably 0. R ⁸⁰ and e are the same as defined above.
In the general formula (f11-2-3), a12 is preferably 1 to 3, and more preferably 1 or 2. R ⁸⁰ and e are the same as defined above.
In general formula (f11-2-4), a13 is preferably 1 to 3, and more preferably 1 or 2. R ⁸⁰ and e are the same as defined above.

  Specific examples of the structural units represented by the general formulas (f11-1-1) to (f11-1-5) and general formulas (f11-2-1) to (f11-2-4) are shown below. .

  The structural unit (f11) is composed of structural units represented by the general formulas (f11-1-1) to (f11-1-5) and (f11-2-1) to (f11-2-4). Preferably, at least one selected from the group is represented by the general formulas (f11-1-1) to (f11-1-5), (f11-2-1) and (f11-2-2) At least one selected from the group consisting of units is more preferred, and a group consisting of structural units represented by the general formulas (f11-1-1), (f11-1-5) and (f11-2-2) At least one selected from is particularly preferred.

As the structural unit (f11), one type may be used alone, or two or more types may be used in combination.
When the component (F11) is contained in the component (F), the proportion of the component (f11) is preferably 10 to 90 mol% with respect to the total of all the components constituting the component (F). 20-90 mol% is more preferable, 30-90 mol% is especially preferable, and 100 mol% may be sufficient. When the proportion of the structural unit (f11) is not less than the lower limit of the above range, in the formation of the resist pattern, the characteristics that become hydrophobic during immersion exposure are further improved.

(Structural unit (f12))
Preferable specific examples of the structural unit (f12) include structural units represented by the following general formula (f12-1).

［式（ｆ１２−１）中、Ｒはそれぞれ独立して水素原子、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；Ｑ^０’は単結合又は二価の連結基であり、Ｒ^７２は酸解離性基である。］

[In formula (f12-1), each R is independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms; Q ⁰ ′ is a single bond or a divalent group. R ⁷² is an acid dissociable group. ]

In general formula (f12-1), R is the same as defined above, and more preferably a hydrogen atom or a methyl group.
Examples of the acid dissociable group for R ⁷² include the same as those exemplified in the description of the acid dissociable group for R ⁷⁰ .

In the general formula (f12-1), examples of the structural unit in which Q ⁰ ′ is a single bond include structural units represented by the following general formulas (f12-1-1) to (f12-1-4). It is mentioned as a suitable thing.
In the general formula (f12-1), when Q ⁰ ′ is a divalent linking group, the divalent linking group is the same as that of X _{01 in the} formula (f11-2) or a divalent linking group. Aromatic hydrocarbon groups can be mentioned. As a bivalent aromatic hydrocarbon group, a C6-C20 aromatic hydrocarbon group is mentioned, The group remove | excluding two hydrogen atoms from benzene, naphthalene, and anthracene is mentioned.
In the structural unit (f12), as Q ⁰ ′, a single bond or —C (═O) —O—R ^d — [R ^d is a straight chain having 1 to 10 carbon atoms which may contain an oxygen atom, or It is a branched alkylene group. The alkylene group may be fluorinated. It is preferable that it is a single bond.
In the general formula (f12-1), examples of the structural unit in which Q ⁰ ′ is —C (═O) —O—R ^d — include, for example, the following general formulas (f12-1-5) to (f12-1). The structural unit represented by -11) is preferable.
However, R in the following general formula is the same as the above R, and is preferably a hydrogen atom or a methyl group.

  The structural unit (f12) is preferably at least one selected from the group consisting of structural units represented by the general formulas (f12-1-1) to (f12-1-11). The structural units represented by (1-1) to (f12-1-4) are particularly preferable.

In the component (F), as the structural unit (f12), one type of structural unit may be used alone, or two or more types may be used in combination.
When the component (F12) is contained in the component (F), the proportion of the component (f12) is preferably 10 to 100 mol% with respect to the total of all the components constituting the component (F). 30-90 mol% is more preferable, and 50-90 mol% is especially preferable. When the proportion of the structural unit (f12) is not less than the lower limit of the above range, the characteristics that become hydrophobic during exposure are further improved in the formation of the resist pattern. Further, the lithography characteristics are further improved. If it is less than or equal to the upper limit of the range, it is possible to balance with other structural units. The structural unit (f12) can also be used as a homopolymer.

[Other structural units]
Component (F) may contain other structural units (hereinafter referred to as structural unit (f2)) other than the structural unit (f1) as long as the effects of the present invention are not impaired.
Preferable examples of the structural unit (f2) include those similar to the structural unit (a1). More preferably, it is a structural unit represented by the above formula (a1-0-11).
In the structural unit (f2), in the above formula (a1-0-11), an alkyl group represented by R ²¹ is preferably an ethyl group, an n-propyl group, or an n-butyl group.
The aliphatic monocyclic group formed together with the carbon atom to which R ²² is bonded is preferably an 8 to 11 membered ring, more preferably an 8 to 10 membered ring.

In the component (F), as the structural unit (f2), one type may be used alone, or two or more types may be used in combination.
When the component (F2) is contained in the component (F), the proportion of the component (f2) is preferably 5 to 80 mol% based on the total of all the components constituting the component (F). 10-60 mol% is more preferable, 15-50 mol% is further more preferable, and 20-40 mol% is especially preferable. When the proportion of the structural unit (f2) is equal to or greater than the lower limit of the above range, the resist pattern is more hydrophobic when exposed and is more hydrophilic when exposed and exposed to PEB. Become. In addition, the bridge defect can be suppressed in the line and space pattern, and the defective opening defect can be suppressed in the contact hole pattern. Moreover, the ratio of the hydrocarbon group is improved, and the scan followability at the time of immersion exposure is improved. If it is not more than the upper limit, the balance with the structural unit (f1) will be good.

The component (F) may have a structural unit other than the structural units (f1) to (f2) (hereinafter referred to as the structural unit (f3)) as long as the effects of the present invention are not impaired.
The structural unit (f3) is not particularly limited as long as it is derived from a compound that can be copolymerized with the compound that derives the structural unit (f1) and the compound that derives the structural unit (f2). As such a structural unit, what has been proposed as a structural unit of a base resin for a chemically amplified resist so far (for example, among the structural units (a2) to (a4), the structural units (f1) to (f2) That do not fall under this category).

In the component (F), as the structural unit (f3), one type may be used alone, or two or more types may be used in combination.
When the component (F3) is contained in the component (F), the proportion of the component (f3) is preferably 1 to 25 mol% based on the total of all the components constituting the component (F). 5-20 mol% is more preferable, and 10-20 mol% is especially preferable.

In the present invention, the component (F) is preferably a polymer having the structural unit (f11), a polymer having the structural unit (f12), or a polymer having the structural unit (f1).
As the polymer, a polymer consisting of only one type of structural unit (f11), a copolymer consisting of two or more types of structural units (f11), a polymer consisting of only one type of structural unit (f12), and a configuration Preferred examples include a copolymer composed of the unit (f11) and the structural unit (f2).

The weight average molecular weight (Mw) of the component (F) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, but is preferably 2000 to 50000, more preferably 3000 to 30000, and 4000 to 25000. 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.
Further, the dispersity (Mw / Mn) is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and most preferably 1.2 to 2.5. In addition, Mn shows a number average molecular weight.

(F) A component may be used individually by 1 type and may be used in combination of 2 or more type.
The content of the component (F) in the positive resist composition of the present invention is preferably 0.1 to 50 parts by mass, more preferably 0.1 to 40 parts by mass with respect to 100 parts by mass of the component (A). .5 to 30 parts by mass is particularly preferable, and 0.5 to 15 parts by mass is most preferable.
The effect by mix | blending the said (F) component is fully acquired by setting it as more than the lower limit of the said range. When it is at most the upper limit value, the lithography properties are improved.

  The positive resist composition of the present invention further contains miscible additives as desired, for example, additional resins for improving the performance of the resist film, surfactants for improving coating properties, dissolution inhibitors, Plasticizers, stabilizers, colorants, antihalation agents, dyes, and the like can be added and contained as appropriate.

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

The positive resist composition of the present invention and the component (A1) blended in the positive resist composition are novel ones not conventionally known.
Moreover, according to the positive resist composition of the present invention, a resist film can be formed on a support such as a substrate with good adhesion.
Further, according to the positive resist composition of the present invention, the resist pattern shape to be formed (for example, roundness of the hole when forming a hole pattern, CDU (in-plane uniformity), LWR (line width roughness)) The rectangular shape of the cross-sectional shape is good. LWR is a phenomenon in which the line width of a line pattern becomes non-uniform when a resist pattern is formed using a resist composition, and the improvement becomes more important as the pattern becomes finer.
Further, according to the positive resist composition of the present invention, a resist pattern can be formed with excellent mask reproducibility (for example, mask error factor (MEF)). The MEF is a parameter indicating how faithfully a mask pattern having a different size can be reproduced (mask reproducibility) when the mask size is changed with the same exposure amount and a fixed pitch.
The reason why the above effect is obtained is not clear, but one of the factors is that a specific lactone cyclic group is bonded to the end of a relatively long side chain in the structural unit (a0). It is considered that the distribution of the component (B) in the film becomes uniform, thereby improving the lithography characteristics.

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

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

The exposure method of the resist film may be normal exposure (dry exposure) performed in an inert gas such as air or nitrogen, or may be immersion exposure (Liquid Immersion Lithography).
In immersion exposure, the space between the resist film and the lens at the lowest position of the exposure apparatus is previously filled with a solvent (immersion medium) having a refractive index larger than that of air, and exposure (immersion exposure) is performed in that state. It is an exposure method.
As the immersion medium, a solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film to be exposed is preferable. The refractive index of such a solvent is not particularly limited as long as it is within the above range.
Examples of the solvent having a refractive index larger than the refractive index of air and smaller than the refractive index of the resist film include water, a fluorine-based inert liquid, a silicon-based solvent, and a hydrocarbon-based solvent.
Specific examples of the fluorinated inert liquid include fluorinated compounds 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 main components. 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.

≪Polymer compound≫
The polymer compound of the present invention has a structural unit (a0) represented by the following general formula (a0-1) and a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group. It is a molecular compound.
The description of the polymer compound of the present invention is the same as the description of the component (A1) of the positive resist composition of the present invention.

［式中、Ｒ^１は水素原子、低級アルキル基またはハロゲン化低級アルキル基であり、Ｒ^２は２価の連結基であり、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、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る。］

[Wherein, R ¹ is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ² is a divalent linking group, and R ′ is independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. , An alkoxy group having 1 to 5 carbon atoms or —COOR ″, R ″ is a hydrogen atom or an alkyl group, and 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.]

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.
In this example, the unit represented by the chemical formula (1) is referred to as “compound (1)”, and the same applies to compounds represented by other formulas.

[Monomer Synthesis Example 1 (Synthesis of Compound (2))]
The compound (2) used in the polymer synthesis example described later was synthesized by the following procedure.
In a 500 ml three-necked flask, under a nitrogen atmosphere, 30.23 g (151.71 mmol) of alcohol (1) 30.23 g (157.71 mmol) of ethyldiisopropylaminocarbodiimide (EDCI) hydrochloride and 0.17 mmol of dimethylaminopyridine (DMAP) were added. After adding 300 g of a THF solution of 6 g (5 mmol), 16.67 g (115.66 mmol) of the precursor (1) was added thereto under ice cooling (0 ° C.), and the mixture was stirred at room temperature for 12 hours.
After confirming disappearance of the raw material by thin layer chromatography (TLC), 50 ml of water was added to stop the reaction. The reaction solvent was concentrated under reduced pressure, and the organic layer obtained by extraction with ethyl acetate was washed with saturated sodium bicarbonate solution and water. Furthermore, the solvent was distilled off under reduced pressure, and the resulting product was dried to obtain 26.06 g of Compound (2).
The instrumental analysis result of the obtained compound (2) was as follows.
¹ H-NMR (CDCl ₃ , 400 MHz): δ (ppm) = 6.23 (s, 1 H, Ha or b), 5.67 (s, 1 H, Ha or b), 4.40-4.71 ( m, 3H, Hd, He), 1.38-2.74 (m, 15H, Hc, Hf, Hg, Hh, Hi, Hj, Hk, Hl)

[Monomer Synthesis Example 1-2 (Synthesis of Compound (2 ′))]
Compound (2 ′) was obtained in the same manner as in Monomer Synthesis Example 1 except that the following alcohol (1 ′) was used instead of the alcohol (1).
The instrumental analysis result of the obtained compound (2 ′) was as follows.
_{^{1 H-NMR (CDCl 3,}} 400MHz): δ (ppm) = 6.13 (s, 1H, Ha or Hb), 5.58 (t, 1H, Ha or Hb), 4.96 (s, 1H, He or Hf), 4.60 (s, 2H, Hd), 4.06 (d, 1H, He or Hf), 3.72 (m, 2H, Hl), 3.63 (s, 3H, Hm) , 2.47-2.87 (m, 4H, Hg, Hi, Hj, Hk), 1.90 (s, 3H, Hc), 1.79 (d, 1H, Hh), 1.49 (d, 1H, Hh).

[Monomer Synthesis Example 2 (Synthesis of Compound (11))]
The compound (11) used in the polymer synthesis example described later was synthesized by the following procedure.
A 2 L three-necked flask equipped with a thermometer, a condenser and a stirrer was charged with 37.6 g (494 mmol) of glycolic acid, 700 mL of DMF, 86.5 g (626 mmol) of potassium carbonate, and 28.3 g (170 mmol) of potassium iodide at room temperature. For 30 minutes. Then, 300 mL of dimethylformamide in 100 g (412 mmol) of 2-methyl-2-adamantyl chloroacetate was slowly added. The temperature was raised to 40 ° C. and stirred for 4 hours. After completion of the reaction, 2000 mL of diethyl ether was added and filtered, and the resulting solution was washed 3 times with 500 mL of distilled water. Crystallization was performed using a mixed solution of toluene (300 mL) and heptane (200 mL), and the target product (2- (2- (2-methyl-2-adamantyloxy) -2-oxoethoxy) -2-oxoethanol) Was obtained as a colorless solid (78 g, yield 67%, GC purity 99%).
The instrumental analysis results of the obtained compound were as follows.
¹ H-NMR: 1.59 (d, 2H, J = 12.5 Hz), 1.64 (s, 3H), 1.71 to 1.99 (m, 10H), 2.29 (m, 2H) 2.63 (t, 1H, J = 5.2 Hz), 4.29 (d, 2H, J = 5.2 Hz), 4.67 (s, 2H).
¹³ C-NMR: 22.35, 26.56, 27.26, 32.97, 34.54, 36.29, 38.05, 60.54, 61.50, 89.87, 165.97, 172 .81.
GC-MS: 282 (M +, 0.02%), 165 (0.09%), 149 (40%), 148 (100%), 133 (22%), 117 (2.57%), 89 ( 0.40%).
From the above results, it was confirmed that the obtained compound was 2- (2- (2-methyl-2-adamantyloxy) -2-oxoethoxy) -2-oxoethanol.

Next, 165 g (584 mmol) of 2- (2- (2-methyl-2-adamantyloxy) -2-oxoethoxy) -2-oxoethanol was added to a 2 L three-necked flask equipped with a thermometer, a condenser and a stirrer. , THF 2000 mL, triethylamine 105 mL (754 mmol) and p-methoxyphenol 0.165 g (1000 ppm) were added and dissolved. After dissolution, 62.7 mL (648 mmol) of methacryloyl chloride was slowly added in an ice bath, warmed to room temperature, and stirred for 3 hours. After completion of the reaction, 1000 mL of diethyl ether was added and washed 5 times with 200 mL of distilled water. The extract was concentrated to obtain 198 g (yield 97%, GC purity 99%) of the desired product (compound (11)) as a colorless liquid.
The instrumental analysis result of the obtained compound (11) was as follows.
¹ H-NMR: 1.58 (d, J = 12.5 Hz, 2H), 1.63 (s, 3H), 1.71 to 1.89 (m, 8H), 1.98 (s, 3H) , 2.00 (m, 2H), 2.30 (m, 2H), 4.62 (s, 2H), 4.80 (s, 2H), 5.66 (m, 1H), 6.23 ( m, 1H).
¹³ C-NMR: 18.04, 22.15, 26.42, 27.14, 32.82, 34.38, 36.11, 37.92, 60.44, 61.28, 89.42, 126 79, 135.18, 165.61, 166.30, 167.20.
GC-MS: 350 (M +, 1.4%), 206 (0.13%), 149 (47%), 148 (100%), 133 (20%), 69 (37%).

[Monomer Synthesis Example 3 (Synthesis of Compound (12))]
Compound (12) used in the polymer synthesis example described later was synthesized by the method described in paragraph [0070] of International Publication No. 2007/94473 pamphlet.

[Polymer synthesis example 1]
In a three-necked flask connected with a thermometer and a reflux tube, 11.68 g (68.68 mmol) of compound (1), 15.00 g (51.02 mmol) of compound (2), 16.45 g (62.79 mmol) Compound 3, 4.62 g (27.47 mmol) of Compound (4), 3.24 g (13.74 mmol) of Compound (5) were dissolved in 76.49 g of methyl ethyl ketone (MEK). To this solution, 20.13 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 42.49 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of a normal heptane / isopropyl alcohol mixed solvent, and an operation for precipitating the polymer was performed. The precipitated white powder was filtered, washed with a normal heptane / isopropyl alcohol mixed solvent, and dried. As a result, 30.82 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 was 9,900, and the molecular weight dispersity (Mw / Mn) was 1.45. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o / p = It was 36.3 / 25.6 / 16.8 / 13.4 / 7.9.

[Polymer synthesis example 2]
In a three-necked flask connected with a thermometer and a reflux tube, 12.52 g (73.67 mmol) of compound (1), 13.95 g (47.47 mmol) of compound (2), 17.91 g (68.36 mmol) Compound (3) of 4.78 g (28.48 mmol) of Compound (4) was dissolved in 73.85 g of methyl ethyl ketone (MEK). 21.8 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added to this solution and dissolved.
The resultant was dropwise added to 40.96 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of normal heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a normal heptane / isopropyl alcohol mixed solvent, dried, and the target product. 34 g of the polymer compound 2 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,700, and the molecular weight dispersity (Mw / Mn) was 1.65. The copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 38. It was 2 / 28.5 / 21.0 / 12.3.

[Polymer Synthesis Example 3]
In a three-necked flask connected with a thermometer and a reflux tube, 11.00 g (64.73 mmol) of compound (1), 13.95 g (47.47 mmol) of compound (2), 37.31 g (142.41 mmol) Compound (3), 5.09 g (21.58 mmol) of Compound (5) was dissolved in 101.04 g of methyl ethyl ketone (MEK). To this solution, 27.6 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 56.11 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of normal heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a normal heptane / isopropyl alcohol mixed solvent, dried, and the target product. 33 g of the polymer compound 3 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,300, and the molecular weight dispersity (Mw / Mn) was 1.68. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 33. It was 1 / 24.9 / 32.0 / 10.0.

[Polymer Synthesis Example 4]
In a three-necked flask connected with a thermometer and a reflux tube, 11.00 g (64.73 mmol) of compound (1), 13.95 g (47.47 mmol) of compound (2), 12.69 g (75.52 mmol) Compound (4), 5.09 g (21.58 mmol) of Compound (5) was dissolved in 64.11 g of methyl ethyl ketone (MEK). 20.9 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added to this solution and dissolved.
The resultant was dropwise added to 35.60 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of normal heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a normal heptane / isopropyl alcohol mixed solvent, dried, and the target product. 31 g of the polymer compound 4 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,800, and the molecular weight dispersity (Mw / Mn) was 1.63. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 32. It was 9 / 24.8 / 32.1 / 10.2.

[Polymer synthesis example 5]
In a three-necked flask connected with a thermometer and a reflux tube, 15.37 g (69.23 mmol) of compound (6), 13.95 g (47.47 mmol) of compound (2), 16.58 g (63.29 mmol) Compound (3), 4.65 g (27.69 mmol) of Compound (4), 3.27 g (13.85 mmol) of Compound (5) were dissolved in 80.74 g of methyl ethyl ketone (MEK). To this solution, 22.2 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 44.84 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of normal heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a normal heptane / isopropyl alcohol mixed solvent, dried, and the target product. 37 g of the polymer compound 5 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,600, and the molecular weight dispersity (Mw / Mn) was 1.70. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o / p = It was 35.1 / 26.4 / 18.2 / 13.4 / 6.9.

[Polymer synthesis example 6]
In a three-necked flask connected with a thermometer and a reflux tube, 15.37 g (69.23 mmol) of compound (6), 13.95 g (47.47 mmol) of compound (2), 12.75 g (51.43 mmol) Compound (7), 4.65 g (27.69 mmol) of Compound (4), 3.27 g (13.85 mmol) of Compound (5) were dissolved in 75.00 g of methyl ethyl ketone (MEK). 20.9 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added to this solution and dissolved.
The resultant was dropwise added to 41.65 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of normal heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a normal heptane / isopropyl alcohol mixed solvent, dried, and the target product. 35 g of the polymer compound 6 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,500, and the molecular weight dispersity (Mw / Mn) was 1.60. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o / p = It was 34.3 / 25.7 / 19.5 / 12.9 / 7.6.

[Polymer Synthesis Example 7]
In a three-necked flask connected with a thermometer and a reflux tube, 16.02 g (72.15 mmol) of compound (6), 13.95 g (47.47 mmol) of compound (2), 17.91 g (68.36 mmol) Compound (3), 4.78 g (28.48 mmol) of Compound (4) was dissolved in 79.00 g of methyl ethyl ketone (MEK). To this solution, 21.7 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 43.88 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of normal heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a normal heptane / isopropyl alcohol mixed solvent, dried, and the target product. 26 g of the polymer compound 7 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,100, and the molecular weight dispersity (Mw / Mn) was 1.65. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 37. It was 5 / 28.3 / 21.1 / 13.1.

[Polymer Synthesis Example 8]
In a three-necked flask connected with a thermometer and a reflux tube, 14.37 g (64.73 mmol) of compound (6), 13.95 g (47.47 mmol) of compound (2), 37.31 g (142.41 mmol) Compound (3), 5.09 g (21.58 mmol) of Compound (5) was dissolved in 106.09 g of methyl ethyl ketone (MEK). To this solution, 27.6 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 58.92 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of normal heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a normal heptane / isopropyl alcohol mixed solvent, dried, and the target product. 35 g of the polymer compound 8 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,000, and the molecular weight dispersity (Mw / Mn) was 1.62. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 33. It was 2 / 25.3 / 31.4 / 10.1.

[Polymer synthesis example 9]
In a three-necked flask connected with a thermometer and a reflux tube, 14.37 g (64.73 mmol) of compound (6), 13.95 g (47.47 mmol) of compound (2), 12.69 g (75.52 mmol) Compound (4), 5.09 g (21.58 mmol) of Compound (5) was dissolved in 69.16 g of methyl ethyl ketone (MEK). 20.9 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added to this solution and dissolved.
The resultant was dropwise added to 38.41 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of normal heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a normal heptane / isopropyl alcohol mixed solvent, dried, and the target product. 32 g of the polymer compound 9 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,600, and the molecular weight dispersity (Mw / Mn) was 1.67. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 33. It was 0 / 25.1 / 32.1 / 9.8.

[Polymer Synthesis Example 10]
In a three-necked flask connected with a thermometer and a reflux tube, 17.72 g (63.29 mmol) of compound (8), 13.95 g (47.47 mmol) of compound (2), 16.58 g (63.29 mmol) Compound (3), 4.65 g (27.69 mmol) of compound (4), 3.27 g (13.85 mmol) of compound (5) were dissolved in 84.26 g of methyl ethyl ketone (MEK). To this solution, 25.9 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 46.81 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of normal heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a normal heptane / isopropyl alcohol mixed solvent, dried, and the target product. As a result, 39 g of the polymer compound 10 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,900, and the molecular weight dispersity (Mw / Mn) was 1.63. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o / p = It was 35.1 / 26.2 / 18.2 / 13.7 / 6.8.

[Polymer Synthesis Example 11]
In a three-necked flask connected with a thermometer and a reflux tube, 17.85 g (63.29 mmol) of compound (9), 13.95 g (47.47 mmol) of compound (2), 16.58 g (63.29 mmol) Compound (3), 4.65 g (27.69 mmol) of compound (4), 3.27 g (13.85 mmol) of compound (5) were dissolved in 84.46 g of gamma-butyrolactone (GBL). To this solution, 25.9 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 46.91 g of GBL heated to 80 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of methanol / water mixed solvent, and the polymer was precipitated. The precipitated white powder was filtered, washed with normal heptane / isopropyl alcohol mixed solvent, and dried. As a result, 39 g of the target polymer compound 11 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,500, and the molecular weight dispersity (Mw / Mn) was 1.68. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o / p = It was 35.3 / 26.6 / 18.2 / 13.6 / 6.3.

[Polymer Synthesis Example 12]
In a three-necked flask connected with a thermometer and a reflux tube, 14.62 g (65.27 mmol) of compound (10), 13.95 g (47.47 mmol) of compound (2), 16.58 g (63.29 mmol) Compound (3), 4.65 g (27.69 mmol) of Compound (4), 3.27 g (13.85 mmol) of Compound (5) were dissolved in 79.62 g of gamma-butyrolactone (GBL). To this solution, 26.1 mmol of dimethyl azobisisobutyrate (V-601) was added and dissolved as a polymerization initiator.
The resultant was dropwise added to 44.21 g of GBL heated to 80 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of methanol / water mixed solvent, and the polymer was precipitated. The precipitated white powder was filtered, washed with normal heptane / isopropyl alcohol mixed solvent, and dried. As a result, 37 g of the polymer compound 12 as the target product was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,700, and the molecular weight dispersity (Mw / Mn) was 1.67. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o / p = It was 35.6 / 26.2 / 18.1 / 13.5 / 6.6.

[Polymer Synthesis Example 13]
In a three-necked flask connected with a thermometer and a reflux tube, 15.31 g (68.36 mmol) of compound (10), 13.95 g (47.47 mmol) of compound (2), 17.91 g (68.36 mmol) Compound (3) of 4.78 g (28.48 mmol) of Compound (4) was dissolved in 77.94 g of gamma-butyrolactone (GBL). To this solution, 25.5 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 43.28 g of GBL heated to 80 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of methanol / water mixed solvent, and the polymer was precipitated. The precipitated white powder was filtered, washed with normal heptane / isopropyl alcohol mixed solvent, and dried. As a result, 36 g of the polymer compound 13 as the target product was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,300, and the molecular weight dispersity (Mw / Mn) was 1.66. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 37. It was 9 / 28.3 / 21.0 / 12.8.

[Polymer Synthesis Example 14]
In a three-necked flask connected with a thermometer and a reflux tube, 14.50 g (64.73 mmol) of compound (10), 13.95 g (47.47 mmol) of compound (2), 37.31 g (142.41 mmol) Compound (3), 5.09 g (21.58 mmol) of Compound (5) was dissolved in 106.92 gamma-butyrolactone (GBL). To this solution, 27.6 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 59.03 g of GBL heated to 80 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of methanol / water mixed solvent, and the polymer was precipitated. The precipitated white powder was filtered, washed with normal heptane / isopropyl alcohol mixed solvent, and dried. As a result, 35 g of the target polymer compound 14 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,600, and the molecular weight dispersity (Mw / Mn) was 1.64. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 33. It was 1 / 25.4 / 31.3 / 10.2.

[Polymer Synthesis Example 15]
In a three-necked flask connected with a thermometer and a reflux tube, 14.50 g (64.73 mmol) of compound (10), 13.95 g (47.47 mmol) of compound (2), 12.69 g (75.52 mmol) Compound (4), 5.09 g (21.58 mmol) of Compound (5) was dissolved in 69.36 g of gamma-butyrolactone (GBL). To this solution, 25.1 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 38.51 g of GBL heated to 80 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of normal heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a normal heptane / isopropyl alcohol mixed solvent, dried, and the target product. 32 g of the polymer compound 15 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,900, and the molecular weight dispersity (Mw / Mn) was 1.62. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 32. It was 9 / 24.8 / 32.6 / 9.7.

[Polymer Synthesis Example 16]
In a three-necked flask connected with a thermometer and a reflux tube, 18.74 g (66.46 mmol) of compound (9), 13.95 g (47.47 mmol) of compound (2), 17.91 g (68.36 mmol) Compound (3), 4.78 g (28.48 mmol) of Compound (4) was dissolved in 83.08 g of gamma-butyrolactone (GBL). To this solution, 21.7 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 46.14 g of GBL heated to 80 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of normal heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a normal heptane / isopropyl alcohol mixed solvent, dried, and the target product. As a result, 38 g of the polymer compound 16 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,500, and the molecular weight dispersity (Mw / Mn) was 1.67. The copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 38. It was 0 / 27.8 / 20.8 / 13.4.

[Polymer Synthesis Example 17]
In a three-necked flask connected with a thermometer and a reflux tube, 18.25 g (64.73 mmol) of compound (9), 13.95 g (47.47 mmol) of compound (2), 37.31 g (142.41 mmol) Compound (3), 5.09 g (21.58 mmol) of Compound (5) was dissolved in 111.91 g of gamma butyrolactone (GBL). To this solution, 33.1 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 62.16 g of GBL heated to 80 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of methanol / water mixed solvent, and the polymer was precipitated. The precipitated white powder was filtered, washed with normal heptane / isopropyl alcohol mixed solvent, and dried. As a result, 37 g of the target polymer compound 17 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,200, and the molecular weight dispersity (Mw / Mn) was 1.67. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 33. It was 5 / 25.4 / 31.0 / 10.1.

[Polymer Synthesis Example 18]
In a three-necked flask connected with a thermometer and a reflux tube, 18.25 g (64.73 mmol) of compound (9), 13.95 g (47.47 mmol) of compound (2), 12.69 g (75.52 mmol) Compound (4), 5.09 g (21.58 mmol) of Compound (5) was dissolved in 74.98 g of gamma butyrolactone (GBL). To this solution, 25.1 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 41.64 g of GBL heated to 80 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of methanol / water mixed solvent, and the polymer was precipitated. The precipitated white powder was filtered, washed with normal heptane / isopropyl alcohol mixed solvent, and dried. 35 g of the target polymer compound 18 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,600, and the molecular weight dispersity (Mw / Mn) was 1.62. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 33. It was 3 / 24.7 / 33.1 / 8.9.

[Polymer Synthesis Example 19]
In a three-necked flask connected with a thermometer and a reflux tube, 18.61 g (66.46 mmol) of compound (8), 13.95 g (47.47 mmol) of compound (2), 17.91 g (68.36 mmol) Compound (3) of 4.78 g (28.48 mmol) of Compound (4) was dissolved in 82.89 g of methyl ethyl ketone (MEK). To this solution, 21.7 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 46.03 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of normal heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a normal heptane / isopropyl alcohol mixed solvent, dried, and the target product. As a result, 38 g of the polymer compound 19 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,300, and the molecular weight dispersity (Mw / Mn) was 1.66. The copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 38. It was 1 / 28.2 / 20.1 / 13.6.

[Polymer Synthesis Example 20]
In a three-necked flask connected with a thermometer and a reflux tube, 18.12 g (64.73 mmol) of compound (8), 13.95 g (47.47 mmol) of compound (2), 37.31 g (142.41 mmol) Compound (3), 5.09 g (21.58 mmol) of Compound (5) was dissolved in 111.72 g of methyl ethyl ketone (MEK). To this solution, 33.1 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 62.05 g of MEK heated to 80 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of normal heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a normal heptane / isopropyl alcohol mixed solvent, dried, and the target product. 52 g of the polymer compound 20 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,000, and the molecular weight dispersity (Mw / Mn) was 1.67. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 33. It was 5 / 25.3 / 30.9 / 10.3.

[Polymer Synthesis Example 21]
In a three-necked flask connected with a thermometer and a reflux tube, 18.12 g (64.73 mmol) of compound (8), 13.95 g (47.47 mmol) of compound (2), 12.69 g (75.52 mmol) Compound (4), 5.09 g (21.58 mmol) of Compound (5) was dissolved in 74.79 g of methyl ethyl ketone (MEK). To this solution, 25.1 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 41.53 g of MEK heated to 80 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of methanol / water mixed solvent, and the polymer was precipitated. The precipitated white powder was filtered, washed with normal heptane / isopropyl alcohol mixed solvent, and dried. 35 g of the target polymer compound 21 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,800, and the molecular weight dispersity (Mw / Mn) was 1.67. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 33. It was 2 / 24.7 / 32.8 / 9.3.

[Polymer Synthesis Example 22]
To a three-necked flask connected with a thermometer and a reflux tube, 7.85 g (46.16 mmol) of compound (1), 9.31 g (31.65 mmol) of compound (2), 8.50 g (34.29 mmol) Compound (7), 3.10 g (18.46 mmol) of Compound (4) and 2.18 g (9.23 mmol) of Compound (5) were dissolved in 45.85 g of methyl ethyl ketone (MEK). To this solution, 14.0 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 25.47 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of normal heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a normal heptane / isopropyl alcohol mixed solvent, dried, and the target product. 21 g of the polymer compound 22 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,700, and the molecular weight dispersity (Mw / Mn) was 1.53. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o / p = It was 34.7 / 26.2 / 19.1 / 12.5 / 7.5.

[Polymer Synthesis Example 23]
In a three-necked flask connected with a thermometer and a reflux tube, 19.97 g (67.94 mmol) of compound (2), 12.36 g (35.33 mmol) of compound (11), 20.00 g (108.70 mmol) Compound (12) of 11.54 g (48.92 mmol) of Compound (5) was dissolved in 94.61 g of propylene glycol methyl ether acetate (PM). To this solution, 26.1 mmol of dimethyl azobisisobutyrate (V-601) was added and dissolved as a polymerization initiator.
The resultant was dropwise added to 52.55 g of PM heated to 80 ° C. in a nitrogen atmosphere over 6 hours. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of a methanol / water mixed solvent, and an operation for precipitating the polymer was performed. The precipitated white powder was filtered, washed with a methanol / water mixed solvent, and dried. 44 g of polymer compound 23 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 10,500, and the molecular weight dispersity (Mw / Mn) was 1.47. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 28. It was 0 / 14.2 / 36.0 / 21.8.

[Polymer Synthesis Example 24]
In a three-necked flask connected with a thermometer and a reflux tube, 12.82 g (43.62 mmol) of compound (2), 5.10 g (17.45 mmol) of compound (13), 80.00 g (305.34 mmol) Compound (3), 4.12 g (17.45 mmol) of Compound (5) was dissolved in 152.28 g of propylene glycol methyl ether acetate (PM). To this solution, 15.4 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 84.60 g of PM heated to 80 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of n-heptane, and the polymer was precipitated. The precipitated white powder was filtered off, washed with a methanol / n-heptane mixed solvent and dried. As a result, 23 g of polymer compound 24 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 6,400, and the molecular weight dispersity (Mw / Mn) was 1.29. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 28. It was 1 / 9.5 / 47.6 / 14.8.

[Polymer Synthesis Example 25]
In a three-necked flask connected with a thermometer and a reflux tube, 10.13 g (34.46 mmol) of compound (2), 4.53 g (15.51 mmol) of compound (13), 20.00 g (108.54 mmol) Compound (12) of 3.66 g (15.51 mmol) of Compound (5) was dissolved in 56.87 g of propylene glycol methyl ether acetate (PM). To this solution, 17.4 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 31.59 g of PM heated to 80 ° C. in a nitrogen atmosphere over 6 hours. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of n-heptane, and the polymer was precipitated. The precipitated white powder was filtered, washed with 2-propanol / n-heptane mixed solvent and dried. As a result, 27 g of the polymer compound 25 as the target product was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 9,700, and the molecular weight dispersity (Mw / Mn) was 1.65. The copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 22. It was 4 / 9.1 / 5 / 66.8 / 11.7.

[Polymer Synthesis Example 26]
In a three-necked flask connected with a thermometer and a reflux tube, 9.30 g (31.65 mmol) of compound (2), 9.10 g (38.88 mmol) of compound (14), 4.05 g (17.18 mmol) Compound (5) was dissolved in 33.12 g of methyl ethyl ketone (MEK). To this solution, 5.8 mmol of dimethyl azobisisobutyrate (V-601) was added and dissolved as a polymerization initiator.
The resultant was dropwise added to 18.40 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 6 hours. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of a methanol / water mixed solvent, and an operation for precipitating the polymer was performed. The precipitated white powder was filtered, washed with a methanol / water mixed solvent, and dried. 15 g of the polymer compound 26 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 9,100, and the molecular weight dispersity (Mw / Mn) was 1.53. The copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n = 39.7 / 41.2 / 19.1.

[Polymer Synthesis Example 27]
In a three-necked flask connected with a thermometer and a reflux tube, 9.30 g (31.65 mmol) of compound (2), 6.53 g (38.88 mmol) of compound (4), 4.05 g (17.18 mmol) Compound (5) was dissolved in 29.27 g of methyl ethyl ketone (MEK). To this solution, 7.0 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 16.25 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 6 hours. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization liquid was dropped into a large amount of a methanol / water mixed solvent, and an operation for precipitating the polymer was performed. The precipitated white powder was filtered, washed with a methanol / water mixed solvent, and dried. 14g of the high molecular compound 27 which is a thing was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 9,400, and the molecular weight dispersity (Mw / Mn) was 1.51. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon 13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n = 39.5 / It was 41.0 / 19.5.

[Polymer Synthesis Example 28]
In a three-necked flask connected with a thermometer and a reflux tube, 12.82 g (43.62 mmol) of compound (2), 80.00 g (305.34 mmol) of compound (3), 2.93 g (17.45 mmol) Compound (4), 4.12 g (17.45 mmol) of Compound (5) was dissolved in 149.81 g of methyl ethyl ketone (MEK). To this solution, 15.4 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 83.22 g of MEK heated to 80 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of n-heptane, and the polymer was precipitated. The precipitated white powder was filtered, washed with a methanol / n-heptane mixed solvent, dried, and dried. 25 g of polymer compound 28 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 6,300, and the molecular weight dispersity (Mw / Mn) was 1.41. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 27. It was 4 / 48.6 / 9.7 / 14.3.

[Comparative Polymer Synthesis Example 1]
In a three-necked flask connected with a thermometer and a reflux tube, 10.29 g (43.62 mmol) of compound (15), 80.00 g (305.34 mmol) of compound (3), 2.93 g (17.45 mmol) Compound (4), 4.12 g (17.45 mmol) of Compound (5) was dissolved in 146.01 g of methyl ethyl ketone (MEK). To this solution, 15.4 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved.
The resultant was dropwise added to 81.12 g of MEK heated to 80 ° C. in a nitrogen atmosphere over 3 hours. After completion of dropping, the reaction solution was heated and stirred for 4 hours, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization solution was dropped into a large amount of n-heptane, and the polymer was precipitated. The precipitated white powder was filtered, washed with a methanol / n-heptane mixed solvent, dried, and dried. 25 g of polymer compound 29 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 6,300, and the molecular weight dispersity (Mw / Mn) was 1.41. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n / o = 27. It was 4 / 48.6 / 9.7 / 14.3.

[Comparative Polymer Synthesis Example 2]
In a three-necked flask connected with a thermometer and a reflux tube, 7.47 g (31.65 mmol) of compound (15), 9.10 g (38.88 mmol) of compound (14), 4.05 g (17.18 mmol) Compound (5) was dissolved in 30.93 g of methyl ethyl ketone (MEK). To this solution, 5.8 mmol of dimethyl azobisisobutyrate (V-601) was added and dissolved as a polymerization initiator.
The resultant was dropwise added to 17.18 g of MEK heated to 78 ° C. in a nitrogen atmosphere over 6 hours. After completion of dropping, the reaction solution was heated and stirred for 1 hour, and then the reaction solution was cooled to room temperature.
The obtained reaction polymerization liquid was dropped into a large amount of a methanol / water mixed solvent, and an operation for precipitating the polymer was performed. The precipitated white powder was filtered, washed with a methanol / water mixed solvent, and dried. 14 g of polymer compound 30 was obtained.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 8,900, and the molecular weight dispersity (Mw / Mn) was 1.51. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) is 1 / m / n = 39.8 / It was 41.2 / 19.0.

[Polymer Synthesis Example 29]
The target polymer compound 31 was obtained in the same manner as in the polymer synthesis example except that the compound (2 ′) and the compound (16) were used in a predetermined molar ratio.
The mass average molecular weight (Mw) in terms of standard polystyrene determined by GPC measurement for this polymer compound was 7,300, and the molecular weight dispersity (Mw / Mn) was 1.6. The copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) was 1 / m = 50/50. .

[Examples 1-28, Comparative Examples 1-2]
100 parts by mass of the component (A) shown in Table 1, 9.8 parts by mass of the compound represented by the following chemical formula (B) -1, 0.4 parts by mass of tri-n-pentylamine, and γ- 10 parts by mass of butyrolactone and 2500 parts by mass of a mixed solvent of PGMEA / PGME = 6/4 (mass ratio) were mixed and dissolved to prepare a positive resist composition.
The following evaluation was performed using the obtained resist composition.

(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 on a hot plate at 205 ° C. for 60 seconds to be dried. Thereby, an organic antireflection film having a film thickness of 89 nm was formed. On the antireflection film, each of the resist compositions prepared above was applied using a spinner, and prebaked (PAB) on the hot plate at a PAB temperature shown in Table 1 for 60 seconds. By drying, a resist film having a thickness of 100 nm was formed.
Next, a protective film forming coating solution “TILC-057” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied onto the resist film using a spinner and heated at 90 ° C. for 60 seconds. A top coat having a thickness of 35 nm was formed.
Next, ArF excimer was performed using an ArF immersion exposure apparatus NSR-S609B (manufactured by Nikon; NA (numerical aperture) = 1.07, 2/3 annular illumination, reduction magnification 1/4 times, immersion medium: water). Laser (193 nm) was selectively irradiated through a mask pattern targeting a contact hole pattern (hereinafter referred to as CH pattern) having a hole diameter of 90 nm / pitch of 140 nm.
Thereafter, PEB treatment was carried out at the PEB temperature shown in Table 1 for 60 seconds, followed by development with a 2.38 mass% TMAH aqueous solution NMD-3 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 23 ° C. for 60 seconds, and then for 30 seconds. Then, it was rinsed with pure water and dried by shaking.
As a result, a CH pattern was formed in any of the examples.

(Shape evaluation)
Each CH pattern formed in [Formation of resist pattern] was observed from above using a scanning electron microscope (SEM), and the roundness of each hole pattern was evaluated according to the following criteria. The results are also shown in Table 1.
(Double-circle): There was no unevenness | corrugation of the circumference part of each hole pattern, and it was a favorable shape.
○: A part of the circumference of the hole pattern was missing.
Δ: A part of the circumference of the hole pattern was distorted.
X: The whole circumference of the hole pattern was distorted.

  As shown in the above results, each of the resist compositions of Examples 1 to 28 had a good resist pattern shape.

[Example 29]
Each component shown in Table 2 below, γ-butyrolactone (10 parts by mass), and a mixed solvent (2500 parts by mass) of PGMEA / PGME = 6/4 (mass ratio) are mixed and dissolved to form a positive resist A composition was prepared.

In Table 2, each abbreviation indicates the following, and the numerical value in [] is the blending amount (part by mass).
(A) -29: the polymer compound 31.
(B) -2: A compound represented by the following formula (B) -2.
(B) -3: A compound represented by the following formula (B) -3.
(D) -2: 1,8-naphthalenediamine (F) -1: a fluorine-containing polymer compound represented by the following formula (F) -1. Mw = 25000, Mw / Mn = 1.5, copolymer composition ratio (ratio of each structural unit in the structural formula (molar ratio)): 1 / m = 80/20.

Using the obtained resist composition, a resist pattern was formed by the following procedure, and the following evaluation was performed.
An organic antireflective coating composition “ARC29A” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto an 8-inch silicon wafer using a spinner, and baked at 205 ° C. for 60 seconds on a hot plate and dried. Thereby, an organic antireflection film having a thickness of 77 nm was formed. Then, the resist composition is applied on the antireflection film using a spinner, prebaked (PAB) on a hot plate at 120 ° C. for 60 seconds, and dried to obtain a film thickness of 100 nm. The resist film was formed.
Next, an ArF excimer laser (193 nm) is selectively applied to the resist film through a mask using an ArF exposure apparatus NSR-S302A (manufactured by Nikon; NA (numerical aperture) = 0.6, Annu.). Irradiated. Then, a post-exposure heating (PEB) treatment is performed at 95 ° C. for 60 seconds, and further a condition of 30 seconds with a 2.38 mass% TMAH aqueous solution NMD-3 (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) at 23 ° C. Then, the substrate was alkali-developed, rinsed with pure water for 25 seconds, and then shaken and dried.
As a result, a line and space (L / S) pattern in which lines having a line width of 130 nm were arranged at equal intervals (pitch 260 nm) was formed on the resist film. When the optimum exposure amount Eop (mJ / cm ² ; sensitivity) for forming the L / S pattern was determined, it was 41 mJ / cm ² . Moreover, when the cross-sectional shape of the obtained L / S pattern was observed using a length measuring SEM (scanning electron microscope, trade name: S-9220, manufactured by Hitachi, Ltd.), it was a good rectangular shape pattern. .

[Synthesis of fluorinated polymer compound (F) -1]
Said (F) -1 was synthesize | combined in the following procedures.
(1. Synthesis of monomer (compound (f111)))
In a nitrogen atmosphere at 0 ° C., 61 g (600 mmol) of triethylamine and 64 g (418 mmol) of methyl bromoacetate were added to 300 ml of THF solution of 30 g (348 mmol) of methacrylic acid, and the mixture was returned to room temperature and stirred for 3 hours. After confirming the disappearance of the raw material by thin layer chromatography (TLC), the reaction solution was evaporated under reduced pressure. Water was added to the obtained reaction product, and the mixture was extracted 3 times with ethyl acetate. The organic layer was washed twice with water, and the solvent was distilled off under reduced pressure to obtain 47 g of Compound (21) -1 as a colorless liquid (yield 85%).
Next, 700 ml of a 2.38 mass% TMAH aqueous solution was added to 700 ml of a THF solution in which 30 g (190 mmol) of compound (21) -1 was dissolved at 0 ° C. in a nitrogen atmosphere, followed by stirring at room temperature for 3 hours. After confirming the disappearance of the raw material by thin layer chromatography (TLC), the THF solvent was distilled off under reduced pressure. To the resulting aqueous reaction solution, 50 ml of 10N hydrochloric acid was added at 0 ° C. to adjust the acidity, and then extracted three times with ethyl acetate. The obtained organic layer was washed twice with water, and the solvent was distilled off under reduced pressure to obtain 26 g of Compound (21) -2 as a colorless liquid (yield 95%).
Next, 23.48 g (234.5 mmol) of 2,2,2-trifluoroethanol (CF ₃ CH ₂ OH) and 51.9 g of ethyl diisopropylaminocarbodiimide (EDCI) hydrochloride at 270 ° C. under a nitrogen atmosphere (270. 6 mmol), 26 g (180.39 mmol) of the compound (21) -2 was added to 200 ml of THF solution of 0.11 g (0.9 mmol) of dimethylaminopyridine (DMAP), and the mixture was returned to room temperature and stirred for 3 hours. After confirming the disappearance of the raw materials by thin layer chromatography (TLC), the reaction solution was cooled to 0 ° C., and water was added to stop the reaction. The organic layer obtained by extraction three times with ethyl acetate was washed twice with water. The crude product obtained by evaporating the solvent under reduced pressure was purified by silica gel filtration (ethyl acetate) to obtain 25 g of the objective compound (f111) as a colorless liquid.

About the obtained compound (f111), < ¹ > H-NMR was measured and the structure was confirmed.
The measurement result of ¹ H-NMR is shown below.
_{^{1 H-NMR (CDCl 3,}} 400MHz): δ (ppm) = 6.24 (s, 1H, Hb), 5.70 (s, 1H, Hb), 4.80 (s, 2H, Hc), 4 .60-4.51 (m, 2H, Hd), 1.99 (s, 3H, Ha).

(2. Synthesis of (F) -1)
To a three-necked flask connected with a thermometer and a reflux tube was added 15.00 g (54.32 mmol) of compound (f111), 5.21 g (23.28 mmol) of compound (f211), and 114.52 g of THF. Dissolved. To this solution, 4.66 mmol of dimethyl azobisisobutyrate (V-601) as a polymerization initiator was added and dissolved. The reaction solution was heated and stirred at 80 ° C. for 6 hours under a nitrogen atmosphere, and then cooled to room temperature. The obtained reaction polymerization liquid was concentrated under reduced pressure, then dropped into a large amount of n-heptane, and an operation for precipitating the polymer was performed. The precipitated polymer was filtered, washed, and dried, and the target product containing high fluorine content was obtained. 5.6g of molecular compound (F) -1 was obtained.
For this fluorine-containing polymer compound, the mass average molecular weight (Mw) in terms of standard polystyrene and the molecular weight dispersity (Mw / Mn) were determined by GPC measurement. As a result, the mass average molecular weight (Mw) was 25000, and the molecular weight dispersity (Mw / Mn) was 1.5. The copolymer composition ratio (ratio (molar ratio) of each structural unit in the structural formula) determined by carbon-13 nuclear magnetic resonance spectrum (600 MHz — ¹³ C-NMR) was 1 / m / = 80/20. It was.

Claims (10)

A positive resist composition comprising a base component (A) whose solubility in an alkaline developer is increased by the action of an acid, and an acid generator component (B) that generates an acid upon exposure,
The base material component (A) has a structural unit (a0) represented by the following general formula (a0-1) and a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group. A positive resist composition comprising a polymer compound (A1).

[Wherein, R ¹ is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ² is a divalent linking group, and R ′ is independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. , An alkoxy group having 1 to 6 carbon atoms or —COOR ″, R ″ is a hydrogen atom or an alkyl group, and 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.]   The positive resist composition according to claim 1, wherein the polymer compound (A1) has at least two kinds of the structural unit (a1). The polymer compound (A1) is a structural unit represented by the following general formula (a1-0-11) or a structural unit represented by the following general formula (a1-0-12) as the structural unit (a1). 3. The positive resist composition according to claim 1, further comprising at least one selected from the group consisting of structural units represented by the following general formula (a1-0-2):

[Wherein R is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ²¹ is an alkyl group, and R ²² forms an aliphatic monocyclic group together with the carbon atom to which R ²² is bonded. R ²³ is a branched alkyl group, R ²⁴ is a group that forms an aliphatic polycyclic group together with the carbon atom to which R ²⁴ is bonded, and Y ² is a divalent linking group. X ² is an acid dissociable, dissolution inhibiting group. ]   The positive type according to any one of claims 1 to 3, wherein the polymer compound (A1) further has a structural unit (a3) derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group. Resist composition.   The positive resist composition as described in any one of Claims 1-4 containing a nitrogen-containing organic compound (D).   A step of forming a resist film on a support using the positive resist composition according to claim 1, a step of exposing the resist film, and an alkali developing of the resist film to form a resist A resist pattern forming method including a step of forming a pattern. A polymer compound having a structural unit (a0) represented by the following general formula (a0-1) and a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.

[Wherein, R ¹ is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ² is a divalent linking group, and R ′ is independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. , An alkoxy group having 1 to 6 carbon atoms or —COOR ″, R ″ is a hydrogen atom or an alkyl group, and 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.]   The high molecular compound of Claim 7 which has at least 2 types of the said structural unit (a1). As the structural unit (a1), a structural unit represented by the following general formula (a1-0-11), a structural unit represented by the following general formula (a1-0-12), and the following general formula (a1-0- The polymer compound according to claim 7 or 8, comprising at least one selected from the group consisting of structural units represented by 2).

[Wherein R is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ²¹ is an alkyl group, and R ²² forms an aliphatic monocyclic group together with the carbon atom to which R ²² is bonded. R ²³ is a branched alkyl group, R ²⁴ is a group that forms an aliphatic polycyclic group together with the carbon atom to which R ²⁴ is bonded, and Y ² is a divalent linking group. X ² is an acid dissociable, dissolution inhibiting group. ]   Furthermore, the high molecular compound as described in any one of Claims 7-9 which has a structural unit (a3) induced | guided | derived from the acrylate ester containing a polar group containing aliphatic hydrocarbon group.