JP2013160813A - Resist composition and pattern forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist composition having excellent lithography characteristics and a resist pattern forming method.SOLUTION: A resist composition includes a base component (A) whose solubility in an alkali developer changes by action of acid, and an acid generator component (B) for generating acid by exposure. The acid generator component (B) contains an acid generator (B1) made of a compound represented by a general formula (b1-1) [X represents a 1-15C hydrocarbon group which may have a substituent, Rrepresents a 1-10C hydrocarbon group which may have a substituent, Rrepresents a fluorinated alkyl group, v1 represents an integer of 1 to 5, v2 represents an integer of 0 to 4, and Zrepresents an organic cation].

Description

  The present invention relates to a resist composition excellent in lithography characteristics and resist pattern shape, a resist pattern forming method using the resist composition, a novel compound useful as an acid generator for the resist composition, and an acid generator. .

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

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

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

Various acid generators used in chemically amplified resist compositions have been proposed so far, for example, onium salt acid generators, oxime sulfonate acid generators, diazomethane acid generators. Nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like are known.
Among these, as the acid generator, an onium salt-based acid generator having an onium ion such as triphenylsulfonium in the cation portion is used. As the anion portion of the onium salt-based acid generator, alkyl sulfonate ions or fluorinated alkyl sulfonate ions in which some or all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms are used.
Further, details are as described in Patent Document 2.

JP 2009-025707 A JP 2010-44347 A

Among the onium salt acid generators described above, onium salt acid generators having a perfluoroalkylsulfonic acid ion in the anion moiety are generally used.
However, in recent years, the resist pattern has been further miniaturized, and the conventional chemically amplified resist composition containing an onium salt acid generator having a perfluoroalkyl sulfonate ion in the anion portion has various lithography characteristics. There is a need for improvement. On the other hand, there is a demand for more useful and novel compounds as acid generators for resist compositions.
When a resist pattern is formed using a resist composition containing a photoacid generator described in Patent Document 2, the resist pattern is still insufficient in terms of roughness, mask reproducibility and exposure margin, Further improvement of these characteristics is desired.
This invention is made | formed in view of the said situation, Comprising: It makes it a subject to provide the resist pattern formation method using the resist composition excellent in the lithography characteristic, and the said resist composition.

In order to solve the above problems, the present invention employs the following configuration.
A resist composition comprising a base material component (A) whose solubility in a developer is changed by the action of an acid, and an acid generator component (B) that generates an acid upon exposure, wherein the base material component (A) Contains a resin component (A1) having a structural unit (a2) containing a —SO ₂ — containing cyclic group,
The acid generator component (B) is a resist composition containing an acid generator (B1) composed of a compound represented by the following general formula (b1-1).

[Ｘは置換基を有していてもよい炭素数１〜１５の炭化水素基であり、Ｒ^２は置換基を有していていもよい炭素数１〜１０の炭化水素基であり、Ｒ^３はフッ素化アルキル基であり、ｖ１は１〜5の整数であり、ｖ２は０〜４の整数である。Ｚ^＋は有機カチオンである。]

[X is an optionally substituted hydrocarbon group having 1 to 15 carbon atoms, R ² is an optionally substituted hydrocarbon group having 1 to 10 carbon atoms, and R ³ Is a fluorinated alkyl group, v1 is an integer of 1 to 5, and v2 is an integer of 0 to 4. Z ⁺ is an organic cation. ]

  In a second aspect of the present invention, a resist pattern is formed on a support using the resist composition of the first aspect, the resist film is exposed, and the resist film is developed to form a resist pattern. It is a resist pattern formation method including the process of forming.

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

≪Resist composition≫
The resist composition according to the first aspect of the present invention has a base material component (A) whose solubility in a developing solution is changed by the action of an acid (hereinafter referred to as “component (A)”) and generates an acid upon exposure. The acid generator component (B) (hereinafter referred to as “component (B)”).
When a resist film formed using such a resist composition undergoes selective exposure at the time of resist pattern formation, an acid is generated from the component (B), and the acid changes the solubility of the component (A) in the developer. Let As a result, the solubility of the exposed portion of the resist film in the developer changes, while the solubility of the unexposed portion in the developer does not change. Therefore, when the resist film is developed, the resist composition becomes a positive type. In this case, the exposed portion is dissolved and removed to form a positive resist pattern. When the resist composition is negative, the unexposed portion is dissolved and removed to form a negative resist pattern.
In this specification, a resist composition in which an exposed portion is dissolved and removed to form a positive resist pattern is referred to as a positive resist composition, and a resist composition that forms a negative resist pattern in which an unexposed portion is dissolved and removed. Is referred to as a negative resist composition. The resist composition of the present invention may be a positive resist composition or a negative resist composition. In addition, the resist composition of the present invention may be used for an alkali development process using an alkali developer for development processing at the time of forming a resist pattern. It may be for the solvent development process used. Preferably, it is used for forming a positive resist pattern in an alkali development process. In this case, as the component (A), one whose solubility in an alkali developer is increased by the action of an acid is used. It is done.

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

When the resist composition of the present invention is a resist composition that forms a negative pattern in an alkali development process (or forms a positive resist pattern in a solvent development process), the component (A) is soluble in an alkaline developer. A base material component (hereinafter sometimes referred to as (A0 ′) component) is used, and a crosslinking agent component is further blended. In such a resist composition, when an acid is generated from the component (B) by exposure, the acid acts to cause crosslinking between the component (A0 ′) and the crosslinking agent component, resulting in solubility in an alkali developer. Decrease (increase in solubility in organic developer). Therefore, in the formation of a resist pattern, when a resist film obtained by coating the resist composition on a support is selectively exposed, the exposed portion is hardly soluble in an alkali developer (to an organic developer). On the other hand, the unexposed area remains soluble (almost insoluble in the organic developer) while remaining undissolved in the alkali developer, so that a negative resist pattern can be formed by developing with an alkali developer. . At this time, if an organic developer is used as the developer, a positive resist pattern can be formed.
As the component (A0 ′), a known resin can be used as a resin that is soluble in an alkali developer (hereinafter referred to as “alkali-soluble resin”).
Examples of the alkali-soluble resin include α- (hydroxyalkyl) acrylic acid or α- (hydroxyalkyl) acrylic acid alkyl ester (preferably having 1 to 5 carbon atoms) disclosed in, for example, JP-A-2000-206694. Resin having a unit derived from at least one selected from alkyl ester); disclosed in US Pat. No. 6,949,325, an atom other than a hydrogen atom or a substituent is bonded to the α-position carbon atom having a sulfonamide group Acrylic resin or polycycloolefin resin that may be used; disclosed in US Pat. No. 6,949,325, Japanese Patent Application Laid-Open No. 2005-336252, Japanese Patent Application Laid-Open No. 2006-317803, and contains α-position. An atom other than a hydrogen atom or a substituent may be bonded to the carbon atom. Acrylic resin; disclosed in Japanese 2006-259582 discloses, polycycloolefin resins having fluorinated alcohol, with minimal swelling can formation of a satisfactory resist pattern.
In addition, the α- (hydroxyalkyl) acrylic acid is an α-position carbon atom to which a carboxy group is bonded among acrylic acids in which an atom other than a hydrogen atom or a substituent may be bonded to the α-position carbon atom. One or both of acrylic acid to which a hydrogen atom is bonded and α-hydroxyalkyl acrylic acid in which a hydroxyalkyl group (preferably a hydroxyalkyl group having 1 to 5 carbon atoms) is bonded to the α-position carbon atom Show.
As the crosslinking agent component, for example, it is usually preferable to use an amino crosslinking agent such as glycoluril having a methylol group or an alkoxymethyl group, a melamine crosslinking agent, or the like because a good resist pattern with less swelling can be formed. It is preferable that the compounding quantity of a crosslinking agent component is 1-50 mass parts with respect to 100 mass parts of alkali-soluble resin.

When the resist composition of the present invention is a resist composition that forms a positive pattern in an alkali development process and forms a negative pattern in a solvent development process, the component (A) is preferably an action of an acid. A substrate component (A0) (hereinafter referred to as “(A0) component”) having an increased polarity is used. Since the polarity of the component (A0) changes before and after exposure, good development contrast can be obtained not only in the alkali development process but also in the solvent development process.
That is, when applying an alkali development process, the component (A0) is hardly soluble in an alkali developer before exposure, and when acid is generated from the component (B) by exposure, the polarity increases due to the action of the acid. As a result, the solubility in an alkali developer increases. Therefore, in the formation of a resist pattern, when a resist film obtained by applying the resist composition on a support is selectively exposed, the exposed portion changes from slightly soluble to soluble in an alkaline developer. Since the unexposed portion remains hardly soluble in alkali and does not change, a positive pattern can be formed by alkali development.
On the other hand, when the solvent development process is applied, the component (A0) is highly soluble in an organic developer before exposure, and when acid is generated from the component (B) upon exposure, the acid acts to polarize it. Becomes higher and the solubility in an organic developer decreases. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the resist composition on the support is selectively exposed, the exposed portion changes from soluble to poorly soluble in an organic developer. On the other hand, since the unexposed portion remains soluble and does not change, by developing with an organic developer, a contrast can be provided between the exposed portion and the unexposed portion, and a negative pattern can be formed.

  In the resist composition of the present invention, the component (A) is preferably the component (A0). That is, the resist composition of the present invention is preferably a chemically amplified resist composition that becomes positive in the alkali development process and negative in the solvent development process.

[(A1) component]
The component (A) contains a resin component (A1) having a structural unit (a2) containing a —SO ₂ -containing cyclic group (hereinafter referred to as “(A1) component”).

(Structural unit (a2))
The structural unit (a2) is a structural unit (a2) containing a —SO ₂ — containing cyclic group.
The —SO ₂ — containing cyclic group of the structural unit (a2) is effective in enhancing the adhesion of the resist film to the substrate when the component (A1) is used for forming the resist film. Moreover, it is effective in the alkali development process in that the affinity with a developer containing water such as an alkali developer is improved.

Here, the “—SO ₂ -containing cyclic group” refers to a cyclic group containing a ring containing —SO ₂ — in the ring skeleton, specifically, a sulfur atom in —SO ₂ — ( S) is a cyclic group that forms part of the ring skeleton of the cyclic group. The ring containing —SO ₂ — in the ring skeleton is counted as the first ring, and when it is only the ring, it is a monocyclic group, and when it has another ring structure, it is a polycyclic group regardless of the structure. Called. The —SO ₂ — containing cyclic group may be monocyclic or polycyclic.
-SO ₂ - containing cyclic group, in particular, -O-SO ₂ - within the ring skeleton cyclic group containing, i.e. -O-SO ₂ - -O-S- medium is a part of the ring skeleton It is preferably a cyclic group containing a sultone ring to be formed.
The —SO ₂ — containing cyclic group preferably has 3 to 30 carbon atoms, more preferably 4 to 20 carbon atoms, still more preferably 4 to 15 carbon atoms, and particularly preferably 4 to 12 carbon atoms. preferable. However, the carbon number is the number of carbon atoms constituting the ring skeleton, and does not include the carbon number in the substituent.
The —SO ₂ — containing cyclic group may be an —SO ₂ — containing aliphatic cyclic group or an —SO ₂ — containing aromatic cyclic group. Preferably -SO ₂ - containing aliphatic cyclic group.
The —SO ₂ -containing aliphatic cyclic group includes at least a hydrogen atom from an aliphatic hydrocarbon ring in which a part of carbon atoms constituting the ring skeleton is substituted with —SO ₂ — or —O—SO ₂ —. One group is excluded. More specifically, a group obtained by removing at least one hydrogen atom from an aliphatic hydrocarbon ring in which —CH ₂ — constituting the ring skeleton is substituted with —SO ₂ —, —CH ₂ — constituting the ring And a group obtained by removing at least one hydrogen atom from an aliphatic hydrocarbon ring in which CH ₂ — is substituted with —O—SO ₂ —.
The alicyclic hydrocarbon ring preferably has 3 to 20 carbon atoms, and more preferably 3 to 12 carbon atoms.
The alicyclic hydrocarbon ring may be polycyclic or monocyclic. The monocyclic alicyclic hydrocarbon group is preferably a group in which two hydrogen atoms are removed from a monocycloalkane having 3 to 6 carbon atoms. Examples of the monocycloalkane include cyclopentane and cyclohexane. As the polycyclic alicyclic hydrocarbon ring, 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, tetracyclododecane and the like.

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

［式中、Ａ’は酸素原子もしくは硫黄原子を含んでいてもよい炭素数１〜５のアルキレン基、酸素原子または硫黄原子であり、ｚは０〜２の整数であり、Ｒ^２７はアルキル基、アルコキシ基、ハロゲン化アルキル基、水酸基、−ＣＯＯＲ”、−ＯＣ（＝Ｏ）Ｒ”、ヒドロキシアルキル基またはシアノ基であり、Ｒ”は水素原子またはアルキル基である。］

[In the formula, A ′ is an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom or a sulfur atom, an oxygen atom or a sulfur atom, z is an integer of 0 to 2, and R ²⁷ is an alkyl group. , An alkoxy group, a halogenated alkyl group, a hydroxyl group, —COOR ″, —OC (═O) R ″, a hydroxyalkyl group or a cyano group, and R ″ is a hydrogen atom or an alkyl group.]

In the general formulas (3-1) to (3-4), A ′ represents an alkylene group having 1 to 5 carbon atoms which may contain an oxygen atom (—O—) or a sulfur atom (—S—), An oxygen atom or a sulfur atom.
The alkylene group having 1 to 5 carbon atoms in A ′ is preferably a linear or branched alkylene group, and examples thereof include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group.
When the alkylene group contains an oxygen atom or a sulfur atom, specific examples thereof include a group in which —O— or —S— is interposed between the terminal or carbon atoms of the alkylene group, such as —O—CH _{2. -, - CH 2 -O-CH} 2 -, - S-CH 2 -, - CH 2 -S-CH 2 - , and the like.
A ′ is preferably an alkylene group having 1 to 5 carbon atoms or —O—, more preferably an alkylene group having 1 to 5 carbon atoms, and most preferably a methylene group.
z may be any of 0 to 2, and is most preferably 0.
When z is 2, the plurality of R ²⁷ may be the same or different.
As the alkyl group, alkoxy group, halogenated alkyl group, —COOR ″, —OC (═O) R ″, and hydroxyalkyl group in R ²⁷ , the —SO ₂ — containing cyclic group has the above-mentioned, respectively. And the same alkyl groups, alkoxy groups, halogenated alkyl groups, —COOR ″, —OC (═O) R ″, and hydroxyalkyl groups as those which may be substituted.
Below, the specific cyclic group represented by the said general formula (3-1)-(3-4) is illustrated. In the formula, “Ac” represents an acetyl group.

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

The structural unit (a2) is not particularly limited as long as it has a —SO ₂ — containing cyclic group, but the hydrogen atom bonded to the carbon atom at the α-position is substituted with a substituent. A structural unit derived from an acrylate ester that may be included and a structural unit of the structural unit (a2) containing a —SO ₂ -containing cyclic group is preferable.

More specifically, examples of the —SO ₂ -containing cyclic structural unit (a2) include structural units represented by the following general formula (a2-0).

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、Ｒ^２８は−ＳＯ_２−含有環式基であり、Ｒ^２９は単結合または２価の連結基である。］

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ²⁸ represents a —SO ₂ — containing cyclic group, and R ²⁹ represents a single bond. Or it is a bivalent coupling group. ]

In formula (a2-0), R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms.
The alkyl group having 1 to 5 carbon atoms in R is preferably a linear or branched alkyl group, and specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group. Tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like.
Examples of the halogenated alkyl group having 1 to 5 carbon atoms in R include a group in which part or all of the hydrogen atoms of the aforementioned “alkyl group having 1 to 5 carbon atoms in R” are substituted with a halogen atom. 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.
Especially, it is preferable that R is a hydrogen atom, a C1-C5 alkyl group, or a C1-C5 fluorinated alkyl group, and it is a hydrogen atom or a methyl group from industrial availability. It is particularly preferred.

R ²⁸ is the same as the —SO ₂ — containing cyclic group mentioned above.
R ²⁹ may be a single bond or a divalent linking group. Since it is excellent in the effect of this invention, it is preferable that it is a bivalent coupling group.
Examples of the divalent linking group for R ^29, not particularly limited, for example, include the same divalent linking group for ^{Y 2} in below formula (a1-0-2). Among these, those containing an alkylene group or an ester bond (—C (═O) —O—) are preferable.
The alkylene group is preferably a linear or branched alkylene group. Specifically, the same as the linear alkylene group and the branched alkylene group mentioned as the aliphatic hydrocarbon group for Y ² can be used.
As the divalent linking group containing an ester bond, in particular, the general formula: —R ³⁰ —C (═O) —O— [wherein R ³⁰ is a divalent linking group. ] Is preferable. That is, the structural unit (a2) is preferably a structural unit represented by the following general formula (a2-0-1).

［式中、ＲおよびＲ^２８はそれぞれ前記と同様であり、Ｒ^３０は２価の連結基である。］

[Wherein, R and R ²⁸ are the same as defined above, and R ³⁰ is a divalent linking group. ]

R ³⁰ is not particularly limited, and examples thereof include the same divalent linking groups as Y ² in formula (a1-0-2) described later.
As the divalent linking group for R ^30, a linear or branched alkylene group, an aliphatic hydrocarbon group containing a ring in the structure, or a divalent linking group containing a hetero atom is preferable. Alternatively, a branched alkylene group or a divalent linking group containing an oxygen atom as a hetero atom is preferable.
As the linear alkylene group, a methylene group or an ethylene group is preferable, and a methylene group is particularly preferable.
As the branched alkylene group, an alkylmethylene group or an alkylethylene group is preferable, and —CH (CH ₃ ) —, —C (CH ₃ ) ₂ — or —C (CH ₃ ) ₂ CH ₂ — is particularly preferable.
The divalent linking group containing an oxygen atom is preferably a divalent linking group containing an ether bond or an ester bond, and the above-described —Y ²¹ —O—Y ²² —, — [Y ²¹ —C (═O) —O] _{m ′} —Y ²² — or —Y ²¹ —O—C (═O) —Y ²² — is more preferable. Y ²¹ , Y ²² and m ′ are the same as described above.

  As the structural unit (a2), a structural unit represented by general formula (a2-0-11) or (a2-0-12) shown below is preferred, and a structural unit represented by formula (a2-0-12) Units are more preferred.

［式中、Ｒ、Ａ’、Ｒ^２７、ｚおよびＲ^３０はそれぞれ前記と同じである。］

[Wherein, R, A ′, R ²⁷ , z and R ³⁰ are the same as defined above. ]

In formula (a2-0-11), A ′ is preferably a methylene group, an oxygen atom (—O—) or a sulfur atom (—S—).
R ³⁰ is preferably a linear or branched alkylene group or a divalent linking group containing an oxygen atom. As the linear or branched alkylene group and the divalent linking group containing an oxygen atom in R ^30, the linear or branched alkylene group mentioned above and a divalent linking group containing an oxygen atom are mentioned. Examples are the same as the linking group.
As the structural unit represented by the formula (a2-0-12), a structural unit represented by the following general formula (a2-0-12a) or (a2-0-12b) is particularly preferable.

［式中、ＲおよびＡ’はそれぞれ前記と同じであり、ｃ〜ｅはそれぞれ独立に１〜３の整数である。］

[Wherein, R and A ′ are the same as defined above, and c to e are each independently an integer of 1 to 3.] ]

  The structural unit (a2) contained in the component (A1) may be one type or two or more types. When the component (A1) has the structural unit (a2), the proportion of the structural unit (a2) is preferably 1 to 80 mol% with respect to the total of all the structural units constituting the component (A1). It is more preferably 10 to 70 mol%, further preferably 10 to 60 mol%, particularly preferably 10 to 50 mol%. By setting it to the lower limit value or more, the effect of containing the structural unit (a2) can be sufficiently obtained, and by setting it to the upper limit value or less, it is possible to balance with other structural units, such as various kinds of DOF, CDU, etc. The lithography characteristics and pattern shape of the film are improved.

(Structural unit (a1))
The structural unit (a1) is a structural unit containing an acid-decomposable group whose polarity is increased by the action of an acid.
The “acid-decomposable group” is an acid-decomposable group capable of cleaving at least a part of the bond in the structure of the acid-decomposable group by the action of an acid generated from the component (B) upon exposure.
Examples of the acid-decomposable group whose polarity increases by the action of an acid include a group that decomposes by the action of an acid to generate a polar group.
Examples of the polar group constituting the acid-decomposable group include a carboxy group, a hydroxyl group, an amino group, a sulfo group (—SO ₃ H), and the like. Among these, a carboxy group or a hydroxyl group is preferable, and a carboxy group is particularly preferable.
More specifically, examples of the acid-decomposable group include a group in which the polar group is protected with an acid-dissociable group (for example, a group in which a hydrogen atom of the polar group is protected with an acid-dissociable group).
The “acid-dissociable group” is an acid dissociation that can cleave at least a bond between the acid-dissociable group and an atom adjacent to the acid-dissociable group by the action of an acid generated from the component (B) upon exposure. It is a group having properties. The acid-dissociable group constituting the acid-decomposable group must be a group having a lower polarity than the polar group generated by dissociation of the acid-dissociable group. Is dissociated, a polar group having a polarity higher than that of the acid dissociable group is generated, and the polarity of the component (A) is increased. Increased polarity of component (A) increases the solubility of the exposed area in the alkaline developer in the case of an alkali development process, and decreases the solubility of the exposed area in the organic developer in the case of a solvent development process. .

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

Examples of the tertiary alkyl ester type acid dissociable group include an aliphatic branched acid dissociable group and an acid dissociable group containing an aliphatic cyclic group.
Here, “aliphatic branched” means having a branched structure having no aromaticity. The structure of the “aliphatic branched acid dissociable group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
Examples of the aliphatic branched acid dissociable group include a group represented by —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ). ^Wherein, R 71 ^{to R 73} each independently represents a linear alkyl group of 1 to 5 carbon atoms. The group represented by —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ) preferably has 4 to 8 carbon atoms, specifically a tert-butyl group or a 2-methyl-2-butyl group. , 2-methyl-2-pentyl group, 3-methyl-3-pentyl group and the like.
A tert-butyl group is particularly preferable.
In the aliphatic branched acid dissociable group, a part of hydrogen atoms may be substituted with a fluorine atom.
In this case, one of R ⁷¹ , R ⁷² and R ^{73 in} the group represented by —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ) is a fluorinated alkyl group, and two are alkyl groups. It is preferable. As the fluorinated alkyl _group, - _{(CH 2)} w20 group represented by -CF ₃ is preferred. w20 is an integer of 0-3.

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

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

［式中、Ｒ^１４はアルキル基であり、ｇは０〜８の整数である。］

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

［式中、Ｒ^１５およびＲ^１６は、それぞれ独立してアルキル基である。］

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

In formulas (1-1) to (1-9), the alkyl group represented by R ¹⁴ may be linear, branched, or cyclic.
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.
The cyclic alkyl group preferably has 3 to 20 carbon atoms, and more preferably 4 to 12 carbon atoms. 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. Some of the carbon atoms constituting the ring of the cyclic alkyl group may be substituted with an etheric oxygen atom (—O—).
g is preferably an integer of 0 to 3, more preferably an integer of 1 to 3, and still more preferably 1 or 2.
In formulas (2-1) to (2-6), examples of the alkyl group for R ^{15 to} R ¹⁶ include the same alkyl groups as those described above for R ¹⁴ .
In the formulas (1-1) to (1-9) and (2-1) to (2-6), a part of the carbon atoms constituting the ring is substituted with an etheric oxygen atom (—O—). May be.
In formulas (1-1) to (1-9) and (2-1) to (2-6), a hydrogen atom bonded to a carbon atom constituting the ring may be substituted with a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, and a fluorinated alkyl group.

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

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

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

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

［式中、Ｒ^１’、ｎ、Ｙは上記と同じである。］

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

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

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

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

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

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

  The structural unit (a1) is not particularly limited as long as it has an acid-decomposable group, but an acrylic group in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent. A structural unit derived from an acid ester and comprising a structural unit (a11) containing an acid-decomposable group, a hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent, and hydrogen bonded to a benzene ring A structural unit in which a hydrogen atom of a hydroxyl group of a structural unit derived from hydroxystyrene which may be substituted with a substituent other than a hydroxyl group is substituted with an acid-dissociable group or a substituent containing an acid-dissociable group ( a12), a hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent, and a hydrogen atom bonded to the naphthalene ring may be substituted with a substituent other than a hydroxyl group (hydroxynaphtho Structural units hydroxyl hydrogen atoms of constituent units derived from alkylene) is replaced by a substituent containing an acid-dissociable group or an acid-dissociable group (a13), and the like. The structural unit (a11) is preferable from the viewpoint of line edge roughness, and the structural units (a12) to (a13) are preferable from the viewpoint of easily absorbing the EUV wavelength or EB wavelength in lithography using EUV or EB as an exposure light source.

{Structural unit (a11)}
The structural unit (a11) is a structural unit derived from an acrylate ester in which the hydrogen atom bonded to the carbon atom at the α-position may be substituted with a substituent and includes an acid-decomposable group.
Examples of the structural unit (a11) include a structural unit represented by the following general formula (a1-0-1), a structural unit represented by the following general formula (a1-0-2), and the like.

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

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

In general formula (a1-0-1), R is the same as defined above.
X ¹ is not particularly limited as long as it is an acid dissociable group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable groups, acetal type acid dissociable groups, and the like. An ester type acid dissociable group is preferred.
In general formula (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 of Y ^2, but are not limited to, divalent hydrocarbon group which may have a substituent group, and a divalent linking group containing a hetero atom as preferred.

(Divalent hydrocarbon group which may have a substituent)
The hydrocarbon group as the divalent linking 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 specific examples of the aliphatic hydrocarbon group include a linear or branched aliphatic hydrocarbon group, an aliphatic hydrocarbon group containing a ring in the structure, and the like.

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

As the aliphatic hydrocarbon group containing a ring in the structure, a cyclic aliphatic hydrocarbon group which may contain a substituent containing a hetero atom in the ring structure (excluding two hydrogen atoms from the aliphatic hydrocarbon ring) Group), a group in which the cyclic aliphatic hydrocarbon group is bonded to the end of a linear or branched aliphatic hydrocarbon group, and the cyclic aliphatic hydrocarbon group is a linear or branched chain fatty acid. Group intervening in the middle of the group hydrocarbon group. Examples of the linear or branched aliphatic hydrocarbon group include those described above.
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 polycyclic or monocyclic. As the monocyclic aliphatic hydrocarbon group, a group obtained by removing two hydrogen atoms from a monocycloalkane is preferable. The monocycloalkane preferably has 3 to 6 carbon atoms, and specific examples thereof include cyclopentane and cyclohexane. The polycyclic aliphatic hydrocarbon group is preferably a group obtained by removing two hydrogen atoms from a polycycloalkane, and the polycycloalkane preferably has 7 to 12 carbon atoms, specifically adamantane, Examples include norbornane, isobornane, tricyclodecane, and tetracyclododecane.
The cyclic aliphatic hydrocarbon group may or may not have a substituent (a group or atom other than a hydrogen atom) that replaces a hydrogen atom. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxo group (═O).
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.
The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group. Most preferred is an ethoxy group.
Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.
In the cyclic aliphatic hydrocarbon group, a part of carbon atoms constituting the ring structure may be substituted with a substituent containing a hetero atom. As the substituent containing the hetero atom, —O—, —C (═O) —O—, —S—, —S (═O) ₂ —, and —S (═O) ₂ —O— are preferable.

The aromatic hydrocarbon group as the divalent hydrocarbon group is a divalent hydrocarbon group having at least one aromatic ring and may have a substituent. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n + 2 π electrons, and may be monocyclic or polycyclic. It is preferable that carbon number of an aromatic ring is 5-30, 5-20 are more preferable, 6-15 are more preferable, and 6-12 are especially preferable. However, the carbon number does not include the carbon number in the substituent. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene and phenanthrene; aromatic heterocycles in which a part of carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms; etc. Is mentioned. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.
Specifically, the aromatic hydrocarbon group as the divalent hydrocarbon group is a group obtained by removing two hydrogen atoms from the aromatic hydrocarbon ring or aromatic heterocyclic ring (arylene group or heteroarylene group); A group in which two hydrogen atoms have been removed from an aromatic compound (for example, biphenyl, fluorene, etc.) containing one aromatic ring; a group in which one hydrogen atom has been removed from the aromatic hydrocarbon ring or aromatic heterocycle (aryl group or hetero group) A group in which one of the hydrogen atoms of the aryl group is substituted with an alkylene group (for example, a benzyl group, a phenethyl group, a 1-naphthylmethyl group, a 2-naphthylmethyl group, a 1-naphthylethyl group, a 2-naphthylethyl group, etc. A group in which one hydrogen atom is further removed from the aryl group in the arylalkyl group); The alkylene group bonded to the aryl group or heteroaryl group preferably has 1 to 4 carbon atoms, more preferably 1 to 2 carbon atoms, and particularly preferably 1 carbon atom.
The aromatic hydrocarbon group may or may not have a substituent. For example, a hydrogen atom bonded to an aromatic ring of the aromatic group may be substituted with a substituent.
Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxo group (═O).
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.
The alkoxy group as the substituent is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group. Most preferred is an ethoxy group.
Examples of the halogen atom as the substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

(Divalent linking group containing a hetero atom)
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—, —O—C (═O) —O—, _{-S -, - S (= O} ) 2 -, - S (= O) 2 -O -, - NH -, - NH-C (= O) -, - NH-C (= NH) -, = N Non-hydrocarbon linking groups such as-, and combinations of at least one of these non-hydrocarbon linking groups with a divalent hydrocarbon group. Examples of the divalent hydrocarbon group include the same divalent hydrocarbon groups that may have a substituent as described above, and a linear or branched aliphatic hydrocarbon group is preferable. .
Among the above, -NH-, -NH- in -C (= O) -NH-, and H in -NH-C (= NH)-are each substituted with a substituent such as an alkyl group or an acyl group. May be. The substituent preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 5 carbon atoms.

Y ² is particularly preferably a linear or branched alkylene group, a divalent alicyclic hydrocarbon group, or a divalent linking group containing a hetero atom.
When Y ² is a linear or branched alkylene group, the alkylene group preferably has 1 to 10 carbon atoms, more preferably 1 to 6 carbon atoms, and 1 to 4 carbon atoms. It is particularly preferred that it has 1 to 3 carbon atoms. Specifically, in the description of the divalent linking group in R ^1, the same as the linear alkylene group and the branched alkylene group mentioned as the linear or branched aliphatic hydrocarbon group. Things.
When Y ² is a divalent alicyclic hydrocarbon group, as the alicyclic hydrocarbon group, in the description of the divalent linking group in R ^0-1 , “aliphatic containing a ring in the structure”. The thing similar to the alicyclic hydrocarbon group quoted as "hydrocarbon group" is mentioned.
The alicyclic hydrocarbon 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 Y 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-, the formula ^{-Y 21 -O-Y 22 -,} - [Y 21 -C (= O) -O A group represented by _{m ′} —Y ²² — or —Y ²¹ —O—C (═O) —Y ²² —, wherein Y ²¹ and Y ²² each independently have a substituent. It is a good divalent hydrocarbon group, O is an oxygen atom, and m ′ is an integer of 0 to 3. ] Etc. are mentioned.
When Y ² is —NH—, H may be substituted with a substituent such as an alkyl group or an aromatic group (for example, an aryl group). The substituent (alkyl group, aromatic group, etc.) preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and particularly preferably 1 to 5 carbon atoms.
Formula ^{-Y 21 -O-Y 22 -,} - [Y 21 -C (= O) -O] m '-Y 22 - or ^{-Y 21 -O-C (= O} ) -Y 22 - ^{In, Y 21} And Y ²² are each independently a divalent hydrocarbon group which may have a substituent. Examples of the divalent hydrocarbon group include the same groups as those described above as the “divalent hydrocarbon group which may have a substituent” for Y ² .
Y ²¹ is preferably a linear aliphatic hydrocarbon group, more preferably a linear alkylene group, still more preferably a linear alkylene group having 1 to 5 carbon atoms, and particularly preferably a methylene group or an ethylene group. preferable.
Y ²² is preferably a linear or branched aliphatic hydrocarbon group, and more preferably a methylene group, an ethylene group or an alkylmethylene group. The alkyl group in the alkylmethylene group is preferably a linear alkyl group having 1 to 5 carbon atoms, more preferably a linear alkyl group having 1 to 3 carbon atoms, and most preferably a methyl group.
In the group represented by the formula — [Y ²¹ —C (═O) —O] _{m ′} —Y ²² —, m ′ is an integer of 0 to 3, preferably an integer of 0 to 2, Or 1 is more preferable, and 1 is particularly preferable. That is, the group represented by the formula — [Y ²¹ —C (═O) —O] _{m ′} —Y ²² — is represented by the formula —Y ²¹ —C (═O) —O—Y ²² —. The group is particularly preferred. Among these, a group represented by the formula — (CH ₂ ) _{a ′} —C (═O) —O— (CH ₂ ) _{b ′} — is preferable. In the formula, a ′ is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, further preferably 1 or 2, and most preferably 1. b ′ is an integer of 1 to 10, preferably an integer of 1 to 8, more preferably an integer of 1 to 5, more preferably 1 or 2, and most preferably 1.
The divalent linking group containing a hetero atom in Y ² is preferably an organic group comprising a combination of at least one kind, a non-hydrocarbon group and a divalent hydrocarbon group. Among these, a linear group having an oxygen atom as a hetero atom, for example, a group containing an ether bond or an ester bond, is preferable, and the above formulas -Y ²¹ -O-Y ²² -,-[Y ²¹ -C (= O ) —O] _{m ′} —Y ²² — or —Y ²¹ —O—C (═O) —Y ²² — is more preferred, and the group represented by the formula — [Y ²¹ —C (═O) —O] is preferred. _The group represented by m′—Y ²² — or —Y ²¹ —O—C (═O) —Y ²² — is preferred.

Among these, Y ² is preferably a linear or branched alkylene group or a divalent linking group containing a hetero atom, and is a linear or branched alkylene group, the formula -Y ²¹ A group represented by —O—Y ²² —, a group represented by the formula — [Y ²¹ —C (═O) —O] _{m ′} —Y ²² —, or a group represented by the formula —Y ²¹ —O—C ( The group represented by ═O) —Y ²² — is more preferable.

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

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

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

In the formula, X ′ is the same as the tertiary alkyl ester-type acid dissociable group.
^{R 1 ', R 2',} n, as the Y, respectively, ^{R 1} in the general formula listed in the description of "acetal-type acid dissociable group" described above ^{(p1) ', R 2'} , n, similarly to the Y Can be mentioned.
The Y ^2, the same groups as those described above for ^{Y 2} in the 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.

  In the present invention, as the structural unit (a11), 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 ( It preferably has at least one selected from the group consisting of a structural unit represented by a1-0-13) and a structural unit represented by the following general formula (a1-0-2). Among these, a structural unit represented by the formula (a1-0-11), a structural unit represented by the following general formula (a1-0-12), and a structure represented by the following general formula (a1-0-2) It is preferable to have at least one selected from the group consisting of units.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基または炭素数１〜５のハロゲン化アルキル基であり、Ｒ^２１はアルキル基であり、Ｒ^２２は、当該Ｒ^２２が結合した炭素原子と共に脂肪族単環式基を形成する基であり、Ｒ^２３は分岐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、Ｒ^２５は炭素数１〜５の直鎖状のアルキル基である。Ｙ^２は２価の連結基であり、Ｘ^２は酸解離性基である。］

[Wherein, R is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or a halogenated alkyl group having 1 to 5 carbon atoms, R ²¹ is an alkyl group, and R ²² is a carbon to which R ²² is bonded. A group that forms an aliphatic monocyclic group together with an atom, R ²³ is a branched alkyl group, and R ²⁴ is a group that forms an aliphatic polycyclic group together with the carbon atom to which R ²⁴ is bonded. R ²⁵ is a linear alkyl group having 1 to 5 carbon atoms. Y ² is a divalent linking group, and X ² is an acid dissociable group. ]

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

Specific examples of the structural unit represented by the formula (a1-0-11) include the formulas (a1-1-16) to (a1-1-23), (a1-1-27), and (a1-1 -31) and structural units represented by (a1-1-37). Among these, the formulas (a1-1-16) to (a1-1-17), (a1-1-20) to (a1-1-23), (a1-1-27), (a1-1-1- 31), the structural unit represented by the following (a1-1-02) including the structural unit represented by (a1-1-37) is preferable. Moreover, the structural unit represented by the following (a1-1-02 ′) is also preferable.
In each formula, h is preferably 1 or 2.

［式中、Ｒ、Ｒ^２１はそれぞれ前記と同じであり、ｈは１〜４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 4, respectively. ]

In formula (a1-0-12), as the branched alkyl group for R ²³ , the branched alkyl group described for the alkyl group for R ¹⁴ in formulas (1-1) to (1-9) above. 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 group, polycyclic group The thing similar to what is is mentioned.
Specific examples of the structural unit represented by the formula (a1-0-12) include those represented by the formulas (a1-1-26) and (a1-1-28) to (a1-1-30). Units are listed.
As the structural unit represented by the formula (a1-0-12), those in which R ²⁴ is an aliphatic polycyclic group formed together with the carbon atom to which R ²⁴ is bonded are preferably a 2-adamantyl group, The structural unit represented by the formula (a1-1-26) is preferable.

In formula (a1-0-13), R and R ²⁴ are the same as defined above.
Examples of the linear alkyl group for R ²⁵ include the same linear alkyl groups as those described above for the alkyl group for R ^{14 in} the formulas (1-1) to (1-9), and methyl Most preferred are groups or ethyl groups.
Specific examples of the structural unit represented by formula (a1-0-13) include formulas (a1-1-1) to (a1-1-3) exemplified as specific examples of general formula (a1-1). ), Structural units represented by (a1-1-7) to (a1-1-15).
As the structural unit represented by the formula (a1-0-13), those in which R ²⁴ is an aliphatic polycyclic group formed together with the carbon atom to which R ²⁴ is bonded are preferably a 2-adamantyl group, The structural unit represented by the formula (a1-1-1) or (a1-1-2) is preferable.

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), and particularly represented by the formula (a1-3). Are preferred.
As the structural unit represented by the formula (a1-0-2), in particular, Y ² in the formula is a group represented by the formula —Y ²¹ —O—Y ²² —, or the formula — [Y ²¹ —C _{(= O) -O] m '} -Y 22 - group represented by or the formula ^{-Y 21 -O-C (= O} ) -Y 22, - what is a group represented by are preferred.
Preferred examples of the structural unit include a structural unit represented by the following general formula (a1-3-01); a structural unit represented by the following general formula (a1-3-02); 3-03) and the like.

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

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

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

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

In formulas (a1-3-01) to (a1-3-02), R ¹³ is preferably a hydrogen atom.
R ¹⁴ is the same as ^{R 14} in the formula (1-1) to (1-9).
y 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 (a1-0-2).
Y ² ′ is preferably a divalent hydrocarbon group which may have a substituent, more preferably a linear aliphatic hydrocarbon group, and even more preferably a linear alkylene group. Among these, a linear alkylene group having 1 to 5 carbon atoms is preferable, and a methylene group and an ethylene group are most preferable.
Y ² ″ is preferably a divalent hydrocarbon group which may have a substituent, more preferably a linear aliphatic hydrocarbon group, and still more preferably a linear alkylene group. A linear alkylene group of 1 to 5 is preferable, and a methylene group and an ethylene group are most preferable.
Examples of the acid dissociable group in X ′ include the same groups as described above, and are preferably tertiary alkyl ester-type acid dissociable groups. In addition, a group in which a substituent is bonded to a carbon atom bonded to an atom adjacent to the acid dissociable group to form a tertiary carbon atom is more preferable. Preferred are the groups
w is an integer of 0 to 3, and w is preferably an integer of 0 to 2, more preferably 0 or 1, and most preferably 1.
As the structural unit represented by the formula (a1-3-03), a structural unit represented by the following general formula (a1-3-03-1) or (a1-3-03-2) is preferable. The structural unit represented by the formula (a1-3-03-1) is preferable.

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

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

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

{Structural unit (a12)}
In the structural unit (a12), a hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent, and a hydrogen atom bonded to the benzene ring may be substituted with a substituent other than a hydroxyl group. It is a structural unit in which a hydrogen atom of a hydroxyl group of a structural unit derived from styrene is substituted with an acid dissociable group or a substituent containing an acid dissociable group.
“Hydroxystyrene” is a compound in which one vinyl group and at least one hydroxyl group are bonded to a benzene ring. 1-3 are preferable and, as for the number of the hydroxyl groups couple | bonded with a benzene ring, 1 is especially preferable. The bonding position of the hydroxyl group in the benzene ring is not particularly limited. When the number of hydroxyl groups is one, the para 4-position of the vinyl group bonding position is preferred. When the number of hydroxyl groups is an integer of 2 or more, any bonding position can be combined.
Examples of the acid dissociable group for substituting the hydrogen atom of the hydroxyl group include the same groups as those described above, preferably a tertiary alkyl ester type acid dissociable group or an acetal type acid dissociable group, and an acetal type acid dissociable group is More preferred.
Examples of the substituent containing an acid dissociable group include a group composed of an acid dissociable group and a divalent linking group. Examples of the divalent linking group include those similar to the divalent linking group in Q ¹ in the formula (a0-1), and in particular, a group in which the terminal structure on the acid dissociable group side is a carbonyloxy group. Is preferred. In this case, it is preferable that an acid dissociable group is bonded to the oxygen atom (—O—) of the carbonyloxy group.
Examples of the substituent containing an acid dissociable group include a group represented by R ¹¹ ′ —O—C (═O) — and a group represented by R ¹¹ ′ —O—C (═O) —R ¹² ′ —. Is preferred. In the formula, R ¹¹ ′ is an acid dissociable group, and R ¹² ′ is a linear or branched alkylene group.
The acid dissociable group for R ¹¹ ′ is preferably a tertiary alkyl ester type acid dissociable group or an acetal type acid dissociable group, more preferably a tertiary alkyl ester type acid dissociable group. As a preferable example of the tertiary alkyl ester type acid dissociable group, the aliphatic branched acid dissociable group represented by the above-described —C (R ⁷¹ ) (R ⁷² ) (R ⁷³ ), the formula (1- Examples include groups represented by 1) to (1-9), groups represented by formulas (2-1) to (2-6), and the like.
Examples of the alkylene group for R ¹² ′ include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a 1,1-dimethylethylene group. R ¹² ′ is preferably a linear alkylene group.

{Structural unit (a13)}
In the structural unit (a13), a hydrogen atom bonded to the α-position carbon atom may be substituted with a substituent, and a hydrogen atom bonded to the naphthalene ring may be substituted with a substituent other than a hydroxyl group. (Hydroxynaphthalene) (hereinafter referred to as (α-substituted) vinyl (hydroxynaphthalene)) is a structural unit obtained by substituting a hydrogen atom of a hydroxyl group of a structural unit with an acid-dissociable group or a substituent containing an acid-dissociable group. is there.
“Vinyl (hydroxynaphthalene)” is a compound in which one vinyl group and at least one hydroxyl group are bonded to a naphthalene ring. The vinyl group may be bonded to the 1-position of the naphthalene ring or may be bonded to the 2-position. 1-3 are preferable and, as for the number of the hydroxyl groups couple | bonded with a naphthalene ring, 1 is especially preferable. The bonding position of the hydroxyl group in the naphthalene ring is not particularly limited. In the case where a vinyl group is bonded to the 1-position or 2-position of the naphthalene ring, any one of the 5- to 8-positions of the naphthalene ring is preferable. In particular, when the number of hydroxyl groups is one, any one of 5 to 7 positions of the naphthalene ring is preferable, and 5 or 6 positions are preferable. When the number of hydroxyl groups is an integer of 2 or more, any bonding position can be combined.

  In the structural unit (a13), examples of the acid dissociable group for substituting a hydrogen atom of a hydroxyl group and the substituent containing an acid dissociable group include the same groups as those described above for the structural unit (a12). It is done.

As the structural unit (a1) contained in the component (A1), 1 type of structural unit may be used, or 2 or more types may be used.
In the component (A1), the proportion of the structural unit (a1) is preferably 10 to 70 mol%, more preferably 10 to 60 mol%, more preferably 15 to 50 mol%, based on all the 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 a resist composition is formed, and lithography properties such as sensitivity, resolution, and pattern shape are improved. Moreover, the balance with another structural unit can be taken by making it below an upper limit.

(Structural unit (a3))
The component (A1) may further have a structural unit (a3) containing a polar group in addition to the structural unit (a1) or in addition to the structural units (a1) and (a2). When the component (A1) has the structural unit (a3), the polarity of the component (A1) after exposure is further improved. The improvement in polarity contributes to an improvement in resolution and the like, particularly in the case of an alkali development process.
Examples of the polar group include —OH, —COOH, —CN, —SO ₂ NH ₂ , —CONH ₂ , and the like. Those containing —COOH also include structural units of (α-substituted) acrylic acid.
The structural unit (a3) is preferably a structural unit containing a hydrocarbon group in which a part of hydrogen atoms is substituted with a polar group. The hydrocarbon group may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group. Of these, the hydrocarbon group is more preferably an aliphatic hydrocarbon group.
Examples of the aliphatic hydrocarbon group in the hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) and an aliphatic cyclic group (monocyclic group, polycyclic group). Cyclic group).
As the aliphatic cyclic group (monocyclic group, polycyclic group), for example, a resin for a resist composition for ArF excimer laser can be appropriately selected from those proposed. The aliphatic cyclic 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. Specifically, for example, a group in which two or more hydrogen atoms have been removed from a monocycloalkane; a group in which two 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 two or more hydrogen atoms are removed from a monocycloalkane such as cyclopentane or cyclohexane; two or more groups from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, or tetracyclododecane. Examples include a group excluding a hydrogen atom. The aliphatic cyclic group may or may not have a substituent. Examples of the substituent include an alkyl group having 1 to 5 carbon atoms, a fluorine atom, and a fluorinated alkyl group having 1 to 5 carbon atoms.

The aromatic hydrocarbon group in the hydrocarbon group is a hydrocarbon group having at least one aromatic ring. The aromatic ring is not particularly limited as long as it is a cyclic conjugated system having 4n + 2 π electrons, and may be monocyclic or polycyclic. It is preferable that carbon number of an aromatic ring is 5-30, 5-20 are more preferable, 6-15 are more preferable, and 6-12 are especially preferable. However, the carbon number does not include the carbon number in the substituent. Specific examples of the aromatic ring include aromatic hydrocarbon rings such as benzene, naphthalene, anthracene and phenanthrene; aromatic heterocycles in which a part of carbon atoms constituting the aromatic hydrocarbon ring are substituted with heteroatoms; etc. Is mentioned. Examples of the hetero atom in the aromatic heterocyclic ring include an oxygen atom, a sulfur atom, and a nitrogen atom. Specific examples of the aromatic heterocycle include a pyridine ring and a thiophene ring.
Specifically, as an aromatic hydrocarbon group as a divalent hydrocarbon group,
A group obtained by removing two hydrogen atoms from the aromatic hydrocarbon ring or aromatic heterocyclic ring (arylene group or heteroarylene group); a hydrogen atom from an aromatic compound containing two or more aromatic rings (for example, biphenyl, fluorene, etc.); A group in which one of the aromatic ring hydrogen atoms is substituted with an alkylene group (for example, benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2 A group obtained by further removing one hydrogen atom from an aromatic ring in an arylalkyl group or heteroarylalkyl group such as a naphthylethyl group); The number of carbon atoms of the alkylene group that replaces the hydrogen atom of the aromatic hydrocarbon ring or aromatic heterocyclic ring is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1. .
The aromatic hydrocarbon group may have a substituent. For example, the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group may be substituted with a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group as the substituent is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent include groups in which some or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

  As the structural unit (a3), structural units represented by general formula (a3-1) shown below are preferred.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基、又は炭素数１〜５のハロゲン化アルキル基である。Ｌ^０は−Ｃ（＝Ｏ）−Ｏ−、−Ｃ（＝Ｏ）−ＮＲ^ｎ−（Ｒ^ｎは水素原子又は炭素数１〜５のアルキル基である）又は単結合である。Ｒ^０は−ＣＯＯＨ、または置換基として−ＯＨ、−ＣＯＯＨ、−ＣＮ、−ＳＯ_２ＮＨ_２、−Ｃ（Ｒ^ｒ１）（Ｒ^ｒ２）（ＯＨ）及び−ＣＯＮＨ_２からなる群より選択される少なくとも一種の基を有する炭化水素基であり、任意の位置に酸素原子又は硫黄原子を有していてもよい。Ｒ^ｒ１、Ｒ^ｒ２はそれぞれ独立に、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る。］

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. L ⁰ is —C (═O) —O—, —C (═O) —NR ⁿ — (R ⁿ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms) or a single bond. R ⁰ is at least selected from the group consisting of —COOH, or —OH, —COOH, —CN, —SO ₂ NH ₂ , —C (R ^r1 ) (R ^r2 ) (OH) and —CONH ₂ as a substituent. It is a hydrocarbon group having a kind of group, and may have an oxygen atom or a sulfur atom at an arbitrary position. R ^r1 and R ^r2 are each independently a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. ]

In the formula (a3-1), the alkyl group of R is preferably a linear or branched alkyl group, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, Examples include isobutyl group, tert-butyl group, pentyl group, isopentyl group, neopentyl group and the like.
Examples of the halogenated alkyl group for R include groups in which some or all of the hydrogen atoms of the aforementioned R alkyl group have been substituted with halogen atoms. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is particularly preferable.
R is preferably a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a fluorinated alkyl group having 1 to 5 carbon atoms, and particularly preferably a hydrogen atom or a methyl group.
In the formula (a3-1), L ⁰ is —C (═O) —O—, —C (═O) —NR ⁿ — (R ⁿ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. ) Or a single bond. The alkyl group for R ⁿ is the same as the alkyl group for R.

In the formula (a3-1), R ⁰ includes —OH, —COOH, —CN, —SO ₂ NH ₂ , —C (R ^r1 ) (R ^r2 ) (OH), and —CONH ₂ as substituents. It is a hydrocarbon group having at least one group selected from the group, and may have an oxygen atom or a sulfur atom at an arbitrary position.
The “hydrocarbon group having a substituent” means that at least a part of hydrogen atoms bonded to the hydrocarbon group is substituted with a substituent.
The hydrocarbon group for R ⁰ may be an aliphatic hydrocarbon group or an aromatic hydrocarbon group.
As the aliphatic hydrocarbon group for R ^{0, a} linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) or an aliphatic cyclic group (monocyclic group, polycyclic group) Group), and the description thereof is the same as described above.
The aromatic hydrocarbon group in R ⁰ is a hydrocarbon group having an aromatic ring, and this description is the same as described above.
In —C (R ^r1 ) (R ^r2 ) (OH) as a substituent for R ⁰ , R ^r1 and R ^r2 each independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or 1 to 5 carbon atoms. Of the halogenated alkyl group. Examples of the alkyl group having 1 to 5 carbon atoms and the halogenated alkyl group having 1 to 5 carbon atoms include the alkyl group having 1 to 5 carbon atoms and the halogenated alkyl group having 1 to 5 carbon atoms as the substituent at the α-position described above. It is the same.

However, R ⁰ may have an oxygen atom or a sulfur atom at an arbitrary position. The phrase “may have an oxygen atom or a sulfur atom at any position” means a carbon atom constituting a hydrocarbon group or a hydrocarbon group having a substituent (including the carbon atom of the substituent portion). ) May be substituted with an oxygen atom or a sulfur atom, or a hydrogen atom bonded to a hydrocarbon group may be substituted with an oxygen atom or a sulfur atom.
Hereinafter, R ⁰ having an oxygen atom (O) at an arbitrary position will be exemplified as an example.

［式中、Ｗ^００は炭化水素基であり、Ｒ^ｍは炭素数１〜５のアルキレン基である。］

[Wherein, W ⁰⁰ is a hydrocarbon group, and R ^m is an alkylene group having 1 to 5 carbon atoms. ]

In the above formula, W ⁰⁰ is a hydrocarbon group, and examples thereof include the same as R ⁰ in the formula (a3-1). W ⁰⁰ is preferably an aliphatic hydrocarbon group, more preferably an aliphatic cyclic group (monocyclic group or polycyclic group).
R ^m is preferably linear or branched, preferably an alkylene group having 1 to 3 carbon atoms, and more preferably a methylene group or an ethylene group.

More preferable examples of the structural unit (a3) include structural units derived from (α-substituted) acrylic acid, and any one of the following general formulas (a3-11) to (a3-13): Examples of the structural unit are as follows.
Examples of the structural unit derived from (α-substituted) acrylic acid include structural units in which L ⁰ in the formula (a3-1) is a single bond and R ⁰ is —COOH.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基、又は炭素数１〜５のハロゲン化アルキル基である。Ｗ^０１は置換基として−ＯＨ、−ＣＯＯＨ、−ＣＮ、−ＳＯ_２ＮＨ_２、−Ｃ（Ｒ^ｒ１）（Ｒ^ｒ２）（ＯＨ）及び−ＣＯＮＨ_２からなる群より選択される少なくとも一種の基を有する芳香族炭化水素基である。Ｐ^０２及びＰ^０３はそれぞれ−Ｃ（＝Ｏ）−Ｏ−又は−Ｃ（＝Ｏ）−ＮＲ^ｎ−（Ｒ^ｎは水素原子又は炭素数１〜５のアルキル基である）である。Ｗ^０２は置換基として−ＯＨ、−ＣＯＯＨ、−ＣＮ、−ＳＯ_２ＮＨ_２、−Ｃ（Ｒ^ｒ１）（Ｒ^ｒ２）（ＯＨ）及び−ＣＯＮＨ_２からなる群より選択される少なくとも一種の基を有する環状の炭化水素基であり、任意の位置に酸素原子又は硫黄原子を有していてもよい。Ｗ^０３は置換基として−ＯＨ、−ＣＯＯＨ、−ＣＮ、−ＳＯ_２ＮＨ_２、−Ｃ（Ｒ^ｒ１）（Ｒ^ｒ２）（ＯＨ）及び−ＣＯＮＨ_２からなる群より選択される少なくとも一種の基を有する直鎖状の炭化水素基である。Ｒ^ｒ１、Ｒ^ｒ２は前記同様である。］

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. W ⁰¹ represents at least one group selected from the group consisting of —OH, —COOH, —CN, —SO ₂ NH ₂ , —C (R ^r1 ) (R ^r2 ) (OH) and —CONH ₂ as a substituent. It is an aromatic hydrocarbon group. P ⁰² and P ⁰³ are each —C (═O) —O— or —C (═O) —NR ⁿ — (R ⁿ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms). W ⁰² represents at least one group selected from the group consisting of —OH, —COOH, —CN, —SO ₂ NH ₂ , —C (R ^r1 ) (R ^r2 ) (OH) and —CONH ₂ as a substituent. A cyclic hydrocarbon group having an oxygen atom or a sulfur atom at an arbitrary position. W ⁰³ represents at least one group selected from the group consisting of —OH, —COOH, —CN, —SO ₂ NH ₂ , —C (R ^r1 ) (R ^r2 ) (OH) and —CONH ₂ as a substituent. It has a linear hydrocarbon group. R ^r1 and R ^r2 are the same as described above. ]

[Structural Unit Represented by General Formula (a3-11)]
In the formula (a3-11), R is the same as described for R in the formula (a3-1).
The aromatic hydrocarbon group for W ⁰¹ is the same as that described for the aromatic hydrocarbon group for R ⁰ in formula (a3-1).
Specific examples of preferable structural units represented by general formula (a3-11) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

[Structural Unit Represented by General Formula (a3-12)]
In the formula (a3-12), R is the same as described for R in the formula (a3-1).
P ⁰² is —C (═O) —O— or —C (═O) —NR ⁿ — (R ⁿ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms), and —C (═O ) -O-. The alkyl group for R ⁿ is the same as the alkyl group for R.
The cyclic hydrocarbon group in W ⁰² is an aliphatic cyclic group (monocyclic group or polycyclic group) or aromatic hydrocarbon exemplified in the description of R ⁰ in the formula (a3-1). Examples of each group are the same.
W ⁰² may have an oxygen atom or a sulfur atom at an arbitrary position, and this description is the same as the description of R ⁰ in the formula (a3-1).
Specific examples of preferred structural units represented by general formula (a3-12) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

[Structural Unit Represented by General Formula (a3-13)]
In the formula (a3-13), R is the same as described for R in the formula (a3-1).
P ⁰³ is —C (═O) —O— or —C (═O) —NR ⁿ — (R ⁿ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms), and —C (═O ) -O-. The alkyl group for R ⁿ is the same as the alkyl group for R.
The linear hydrocarbon group for W ⁰³ preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and still more preferably 1 to 3 carbon atoms.
The linear hydrocarbon group for W ⁰³ may further have a substituent (a) other than —OH, —COOH, —CN, —SO ₂ NH _2, and —CONH ₂ . Examples of the substituent (a) include an alkyl group having 1 to 5 carbon atoms, an aliphatic cyclic group (monocyclic group, polycyclic group), a fluorine atom, a fluorinated alkyl group having 1 to 5 carbon atoms, and the like. Can be mentioned. The number of carbon atoms of the aliphatic cyclic group (monocyclic group or polycyclic group) in the substituent (a) is preferably 3 to 30, more preferably 5 to 30, and further preferably 5 to 20 Preferably, 6-15 is especially preferable, and 6-12 is the most preferable. Specifically, for example, a group in which two or more hydrogen atoms are removed from a monocycloalkane; a group in which one or more hydrogen atoms are removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, etc. Can be mentioned. More specifically, a group in which two 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.
Further, straight-chain hydrocarbon group for W ^03, as in the structural unit represented by the following general formula as an example (a3-13-a), may have a plurality of substituents (a), A plurality of substituents (a) may be bonded to each other to form a ring.

［式中、Ｒは水素原子、炭素数１〜５のアルキル基、又は炭素数１〜５のハロゲン化アルキル基である。Ｒ^ａ１及びＲ^ａ２はそれぞれ独立に炭素数１〜５のアルキル基、脂肪族環式基（単環式基、多環式基）、フッ素原子、又は炭素数１〜５のフッ素化アルキル基である。但し、Ｒ^ａ１とＲ^ａ２とが相互に結合して環を形成してもよい。ｑ^０は１〜４の整数である。］

[Wherein, R represents a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a halogenated alkyl group having 1 to 5 carbon atoms. R ^a1 and R ^a2 are each independently an alkyl group having 1 to 5 carbon atoms, an aliphatic cyclic group (monocyclic group or polycyclic group), a fluorine atom, or a fluorinated alkyl group having 1 to 5 carbon atoms. is there. However, R ^a1 and R ^a2 may be bonded to each other to form a ring. q ⁰ is an integer of 1 to 4. ]

In the formula (a3-13-a), R is the same as described for R in the formula (a3-1).
The aliphatic cyclic group (monocyclic group or polycyclic group) in R ^a1 and R ^a2 is the same as the aliphatic cyclic group (monocyclic group or polycyclic group) in the substituent (a). is there.
R ^a1 and R ^a2 may be bonded to each other to form a ring. In this ^case, a ^{R a1,} and ^{R a2,} cyclic group is formed by the carbon atoms to which the ^{R a1} and ^{R a2} are bonded together. The cyclic group may be a monocyclic group or a polycyclic group. Specifically, an aliphatic cyclic group (monocyclic group, Examples thereof include groups in which one or more hydrogen atoms have been removed from the monocycloalkane or polycycloalkane exemplified in the description of the polycyclic group).
q ⁰ is preferably 1 or 2, and more preferably 1.

Specific examples of preferable structural units represented by general formula (a3-13) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

The structural unit (a3) contained in the component (A1) may be one type or two or more types.
When the component (A1) has the structural unit (a3), the proportion of the structural unit (a3) is preferably 0 to 85 mol% with respect to all the structural units constituting the component (A1). 80 mol% is more preferable. By setting the proportion of the structural unit (a3) to be equal to or higher than the lower limit value, the effects (resolution, lithography characteristics, pattern shape improvement effect) due to the inclusion of the structural unit (a3) can be sufficiently obtained. This makes it easier to balance with other structural units.

(Other structural units)
The component (A1) includes other structural units (hereinafter referred to as structural units (a4) and (a5)) other than the structural units (a1) to (a3) as long as the effects of the present invention are not impaired. May be.

・ Structural unit (a4)
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 in which a hydrogen atom bonded to a carbon atom at the α-position may be substituted with a substituent, which is an acid non-dissociable aliphatic group A structural unit containing a polycyclic group, a structural unit derived from a styrene monomer, a structural unit derived from a vinyl naphthalene monomer, or the like is preferable. Examples of the polycyclic group include those exemplified in the case of the structural unit (a1), and for ArF excimer laser and KrF excimer laser (preferably for ArF excimer laser). A number of hitherto known materials can be used as the resin component of the resist composition.
In particular, at least one selected from a tricyclodecanyl group, an adamantyl group, a tetracyclododecanyl group, an isobornyl group, and a norbornyl group is preferable in terms of industrial availability. These polycyclic groups may have a linear or branched alkyl group having 1 to 5 carbon atoms as a substituent.
Specific examples of the structural unit (a4) include those represented by the following general formulas (a4-1) to (a4-5).

［式中、Ｒは前記と同じである。］

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

As the structural unit (a4), one type may be used alone, or two or more types may be used in combination.
When the component (A1) contains the structural unit (a4), the proportion of the structural unit (a4) is preferably 1 to 20 mol% with respect to the total of all the structural units constituting the component (A1). 15 mol% is more preferable and 1-10 mol% is further more preferable.

・ Structural unit (a5)
Examples of the structural unit (a5) include those in which R ²⁸ in the general formula (a2-0) is substituted with a lactone-containing cyclic group, and more specifically, the following general formula (a2-1) ) To (a2-5).

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

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

R in the general formulas (a2-1) to (a2-5) is the same as described above.
As the alkyl group, alkoxy group, halogenated alkyl group, —COOR ″, —OC (═O) R ″, and hydroxyalkyl group in R ′, the —SO ₂ — containing cyclic group has the above-mentioned, respectively. And the same alkyl groups, alkoxy groups, halogenated alkyl groups, —COOR ″, —OC (═O) R ″, and hydroxyalkyl groups as those which may be substituted. The same applies to R ″.
R ′ is preferably a hydrogen atom in view of industrial availability.
Examples of A ″ include the same as A ′ in the general formula (3-1). A ″ represents an alkylene group having 1 to 5 carbon atoms, an oxygen atom (—O—) or a sulfur atom (— S-) is preferable, and an alkylene group having 1 to 5 carbon atoms or -O- is more preferable. The alkylene group having 1 to 5 carbon atoms is more preferably a methylene group or dimethylmethylene group, and most preferably a methylene group.
R ²⁹ is the same as ^{R 29} in the aforementioned general formula (a2-0).
In formula (a2-1), s ″ is preferably 1 to 2.
Specific examples of the structural units represented by the general formulas (a2-1) to (a2-5) are shown below. In the following formulas, R ^α represents a hydrogen atom, a methyl group or a trifluoromethyl group.

As the structural unit (a5), one type may be used alone, or two or more types may be used in combination.
When the component (A1) contains the structural unit (a5), the proportion of the structural unit (a5) is preferably 1 to 20 mol% with respect to the total of all the structural units constituting the component (A1). 15 mol% is more preferable and 1-10 mol% is further more preferable.

The component (A1) is a copolymer having the structural unit (a2), and is preferably a copolymer having the structural unit (a1).
Examples of such a copolymer include a copolymer composed of structural units (a1) and (a2); a copolymer composed of structural units (a1), (a2) and (a3); a structural unit (a1), ( Examples thereof include a copolymer comprising a2), (a3) and (a4).
In the present invention, the component (A1) is particularly preferably a combination of structural units represented by the formulas (a1-1-23), (a2-0-12b) and (a3-12-1).

The mass average molecular weight (Mw) of the component (A1) (polystyrene conversion standard by gel permeation chromatography) is not particularly limited, preferably 1000 to 50000, more preferably 1500 to 30000, most preferably 2500 to 20000. preferable. If it is below the upper limit of this range, it has sufficient solubility in a resist solvent to be used as a resist, and if it is above the lower limit of this range, dry etching resistance and resist pattern cross-sectional shape are good.
Further, the dispersity (Mw / Mn) of the component (A1) is not particularly limited, and is preferably 1.0 to 5.0, more preferably 1.0 to 3.0, and 1.2 to 2 .5 is most preferred.
In addition, Mn shows a number average molecular weight.

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

[(A2) component]
The component (A) contains a base material component (hereinafter referred to as the component (A2)) whose solubility in the developer is changed by the action of an acid other than the component (A1) within a range not impairing the effects of the present invention. May be. The component (A2) may be a resin, a low molecular compound, or a mixture thereof.
As the component (A2), a low molecular compound having a molecular weight of 500 or more and less than 4000 and having an acid dissociable group and a hydrophilic group as exemplified in the description of the component (A1) above is preferable. Specific examples include those in which some of the hydrogen atoms of the hydroxyl group of the compound having a plurality of phenol skeletons are substituted with the acid dissociable group.
The component (A2) is, for example, a part of the hydrogen atom of the hydroxyl group of a low molecular weight phenol compound known as a sensitizer in a non-chemically amplified g-line or i-line resist or a heat resistance improver. Those substituted with a functional group are preferred and can be arbitrarily used.
Examples of such low molecular weight phenol compounds include bis (4-hydroxyphenyl) methane, bis (2,3,4-trihydroxyphenyl) methane, 2- (4-hydroxyphenyl) -2- (4′-hydroxyphenyl). ) Propane, 2- (2,3,4-trihydroxyphenyl) -2- (2 ′, 3 ′, 4′-trihydroxyphenyl) propane, tris (4-hydroxyphenyl) methane, bis (4-hydroxy-) 3,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -2-hydroxyphenylmethane, bis (4-hydroxy-3,5-dimethylphenyl) -3, 4-dihydroxyphenylmethane, bis (4-hydroxy-2,5-dimethylphenyl) -3,4-dihydroxyph Phenylmethane, bis (4-hydroxy-3-methylphenyl) -3,4-dihydroxyphenylmethane, bis (3-cyclohexyl-4-hydroxy-6-methylphenyl) -4-hydroxyphenylmethane, bis (3-cyclohexyl- 4-hydroxy-6-methylphenyl) -3,4-dihydroxyphenylmethane, 1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene, Examples include 2 to 6 nuclei of formalin condensates of phenols such as phenol, m-cresol, p-cresol and xylenol. Of course, it is not limited to these. In particular, a phenol compound having 2 to 6 triphenylmethane skeletons is preferable because of excellent resolution and LWR.
The acid dissociable group is not particularly limited, and examples thereof include those described above.
(A2) A component may be used individually by 1 type and may be used in combination of 2 or more type.

In the resist composition of the present invention, as the component (A), one type may be used alone, or two or more types may be used in combination. In addition, inclusion of the component (A1) is essential.
What is necessary is just to adjust content of (A) component according to the resist film thickness etc. which are going to form.

<(B) component>
In the resist composition of the present invention, the component (B) contains an acid generator (B1) (hereinafter referred to as “component (B1)”) composed of a compound represented by the following general formula (b1-1).

[Ｘは置換基を有していてもよい炭素数１〜１５の炭化水素基であり、Ｒ^２は置換基を有していていもよい炭素数１〜１０の炭化水素基であり、Ｒ^３はフッ素化アルキル基であり、ｖ１は１〜5の整数であり、ｖ２は０〜４の整数である。Ｚ^＋は有機カチオンである。]

[X is an optionally substituted hydrocarbon group having 1 to 15 carbon atoms, R ² is an optionally substituted hydrocarbon group having 1 to 10 carbon atoms, and R ³ Is a fluorinated alkyl group, v1 is an integer of 1 to 5, and v2 is an integer of 0 to 4. Z ⁺ is an organic cation. ]

-Anion part of (B1) component In the first general formula (b1-1), X is a hydrocarbon group having 1 to 15 carbon atoms which may have a substituent. Carbon number of the hydrocarbon group of X is 1-15, 3-12 are preferable and 4-12 are more preferable.
R ² is a hydrocarbon group having 1 to 10 carbon atoms which may have a substituent.
R ³ is a fluorinated alkyl group.

  In the group represented by X, 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 5 to 15 carbon atoms, and most preferably 6 to 12 carbon atoms. However, the carbon number does not include the carbon number in the substituent.
Specific examples of the aromatic hydrocarbon group include a hydrogen atom from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, and a phenanthryl group. Aryl groups such as aryl group, benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group, etc., from which one is removed. The number of carbon atoms in the alkyl chain in the arylalkyl group is preferably 1 to 4, more preferably 1 to 2, and particularly preferably 1.

The aromatic hydrocarbon group may have a substituent. For example, a part of carbon atoms constituting the aromatic ring of the aromatic hydrocarbon group may be substituted with a hetero atom, and the hydrogen atom bonded to the aromatic ring of the aromatic hydrocarbon group is substituted with the substituent. May be.
Examples of the former include heteroaryl groups in which some of the carbon atoms constituting the ring of the aryl group are substituted with heteroatoms such as oxygen atoms, sulfur atoms, nitrogen atoms, and aromatic hydrocarbons in the arylalkyl groups. Examples include heteroarylalkyl groups in which some of the carbon atoms constituting the ring are substituted with the above heteroatoms.
Examples of the substituent of the aromatic hydrocarbon group in the latter example include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
The alkyl group as a substituent of the aromatic hydrocarbon group is preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. preferable.
The alkoxy group as a substituent of the aromatic hydrocarbon group is preferably an alkoxy group having 1 to 5 carbon atoms, and is a methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, tert- A butoxy group is preferable, and a methoxy group and an ethoxy group are most preferable.
Examples of the halogen atom as a substituent for the aromatic hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
Examples of the halogenated alkyl group as the substituent of the aromatic hydrocarbon group include groups in which part or all of the hydrogen atoms of the alkyl group have been substituted with the halogen atoms.

The aliphatic hydrocarbon group for X 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 of only the hetero atom, or may be a group containing a group or atom other than the hetero atom.
Specific examples of the substituent for substituting a part of the carbon atom include —O—, —C (═O) —O—, —C (═O) —, —O—C (═O) —O. —, —C (═O) —NH—, —NH— (H may be substituted with a substituent such as an alkyl group, an acyl group, etc.), —S—, —S (═O) ₂ —, — S (= O) ₂ —O— and the like can be mentioned. When the aliphatic hydrocarbon group is cyclic, these substituents may be included in the ring structure.
Specific examples of the substituent for substituting part or all of the hydrogen atoms include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), and a cyano group.
The alkoxy group is preferably an alkoxy group having 1 to 5 carbon atoms, preferably a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group or a tert-butoxy group, and a methoxy group or an ethoxy group. Is most preferred.
As said halogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
As the halogenated alkyl group, a part or all of hydrogen atoms of an alkyl group having 1 to 5 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an n-butyl group, a tert-butyl group, etc. And a group substituted with a halogen atom.

Examples of the aliphatic hydrocarbon group include a linear or branched saturated hydrocarbon group, a linear or branched monovalent unsaturated hydrocarbon group, or a cyclic aliphatic hydrocarbon group (aliphatic ring). Formula group) is preferred.
The linear saturated hydrocarbon group (alkyl group) preferably has 1 to 15 carbon atoms, and most preferably 1 to 10 carbon atoms. Specifically, for example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, isotridecyl group, tetradecyl group Group, pentadecyl group and the like.
The branched saturated hydrocarbon group (alkyl group) preferably has 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. 3-15 are preferable, as for the carbon number, 5-15 are more preferable, and 6-12 are more preferable.
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 most preferred are groups in which one or more hydrogen atoms have been removed from adamantane.
When the aliphatic cyclic group includes a substituent containing a hetero atom in the ring structure, examples of the substituent containing a hetero atom include —O—, —C (═O) —O—, —S—. , —S (═O) ₂ — and —S (═O) ₂ —O— are preferable. Specific examples of the aliphatic cyclic group include the following formulas (L1) to (L6), (S1) to (S4), and the like.

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

[Wherein, Q ″ is an alkylene group having 1 to 5 carbon atoms, —O—, —S—, —O—R ⁹⁴ — or —S—R ⁹⁵ —, 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).
As said alkyl group, a C1-C5 alkyl group is preferable, and it is especially preferable that they are a methyl group, an ethyl group, a propyl group, n-butyl group, and a tert- butyl group.
Examples of the alkoxy group and the halogen atom are the same as those exemplified as the substituent for substituting part or all of the hydrogen atoms.

Among the above, 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. Examples of the polycyclic aliphatic cyclic group include groups obtained by removing one or more hydrogen atoms from the polycycloalkane, and groups represented by the formulas (L2) to (L5) and (S3) to (S4). Etc. are preferred.

R ² is an aromatic hydrocarbon group or an aliphatic hydrocarbon group which may have a substituent. As an aromatic hydrocarbon group and an aliphatic hydrocarbon group, the C1-C10 thing is mentioned among the hydrocarbon groups quoted by said X.

R ² is preferably an aliphatic hydrocarbon containing a heteroatom in the chain in addition to the above-mentioned X, and —COOR ″, —OC (═O) R ″ (R ″ represents a carbon number of 1 to 8 is a linear, branched or cyclic alkyl group.).
When R ″ is a linear or branched alkyl group, it preferably has 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms, and particularly preferably a methyl group or an ethyl group. preferable.
When R ″ is a cyclic alkyl group, it preferably has 3 to 8 carbon atoms, more preferably 4 to 8 carbon atoms, and most preferably 5 to 8 carbon atoms.

The carbon number of the fluorinated alkyl group for R ³ is preferably 1 to 10, more preferably 1 to 5, and still more preferably 1 to 3. Specifically, for example, a group in which a part or all of hydrogen atoms constituting a linear alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group are substituted with fluorine atoms, A part or all of hydrogens constituting a branched alkyl group such as 1-methylethyl group, 1-methylpropyl group, 2-methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, etc. A group in which an atom is substituted with a fluorine atom is exemplified.
The fluorinated alkyl group for R ³ is preferably a group in which some or all of the hydrogen atoms constituting the linear alkyl group are substituted with fluorine atoms. More preferably a fluorinated alkyl group in which the hydrogen atom bonded to the carbon atom at the terminal opposite to is substituted with at least a fluorine atom, and a group in which all of the hydrogen atoms constituting the linear alkyl group are substituted with a fluorine atom (Perfluoroalkyl group) is particularly preferable.
v1 is preferably an integer of 2 to 5.
v2 is preferably an integer of 1 to 4, and more preferably 1 or 2.

-Cation part of (B1) component In formula (b1-1), Z ^<+> represents an organic cation.
The organic cation of Z ⁺ is not particularly limited. For example, it is conventionally known as a cation moiety such as a photodegradable base used for a quencher of a resist composition or an onium acid generator of a resist composition. Organic cations can be used.
As the organic cation of Z ⁺ , for example, a cation moiety represented by the following general formula (c-1) or (c-2) can be used.

［式中、Ｒ^１”〜Ｒ^３”，Ｒ^５”〜Ｒ^６”はそれぞれ独立に置換基を有していてもよいアリール基、アルキル基又はアルケニル基を表す。式（ｃ−１）におけるＲ^１”〜Ｒ^３”のうち、いずれか二つが相互に結合して式中のイオウ原子と共に環を形成してもよい。］

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

In formula (c-1), R ¹ ″ to R ³ ″ each independently represents an aryl group, alkyl group or alkenyl group which may have a substituent. Any two of R ¹ ″ to R ³ ″ may be bonded to each other to form a ring together with the sulfur atom in the formula.
In addition, it is also preferable that at least one of R ¹ ″ to R ³ ″ is an aryl group because the lithography characteristics and the resist pattern shape are further improved.

As the aryl group for R ¹ ″ to R ³ ″, an unsubstituted aryl group having 6 to 20 carbon atoms; some or all of the hydrogen atoms of the unsubstituted aryl group are alkyl groups, alkoxy groups, halogen atoms, hydroxyl groups , An oxo group (═O), an aryl group, an alkoxyalkyloxy group, an alkoxycarbonylalkyloxy group, —C (═O) —O—R ⁶ ′, —O—C (═O) —R ⁷ ′, —O And a substituted aryl group substituted with —R ⁸ ′ and the like. R ⁶ ′, R ⁷ ′ and R ⁸ ′ are each a linear, branched or cyclic saturated hydrocarbon group having 1 to 25 carbon atoms, or a C 2 to 5 carbon atoms. It is a linear or branched aliphatic unsaturated hydrocarbon group.
In R ¹ ″ to R ³ ″, the unsubstituted 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 as a substituent in the substituted aryl group of R ¹ ″ to R ³ ″ is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Most preferably.
As the alkoxy group as a substituent in the substituted 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, or a tert-butoxy group. Most preferably it is.
The halogen atom as a substituent in the substituted aryl group is preferably a fluorine atom.
Examples of the aryl group as a substituent in the substituted aryl group include the same aryl groups as those described above for R ¹ ″ to R ³ ″, preferably an aryl group having 6 to 20 carbon atoms, and an aryl group having 6 to 10 carbon atoms. Group is more preferable, and phenyl group and naphthyl group are more preferable.

As the alkoxyalkyloxy group in the substituted aryl group, for example,
General formula: -O-C ( ^R47 ) ( ^R48 ) -O- ^R49
[Wherein, R ⁴⁷ and R ⁴⁸ each independently represent a hydrogen atom or a linear or branched alkyl group, and R ⁴⁹ represents an alkyl group. ] Is represented.
In R ⁴⁷ and R ⁴⁸ , the alkyl group preferably has 1 to 5 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group.
At least one of R ⁴⁷ and R ⁴⁸ is preferably a hydrogen atom. In particular, it is more preferable that one is a hydrogen atom and the other is a hydrogen atom or a methyl group.
The alkyl group for R ⁴⁹ preferably has 1 to 15 carbon atoms and may be linear, branched or cyclic.
The linear or branched alkyl group for R ⁴⁹ preferably has 1 to 5 carbon atoms, and examples thereof include a methyl group, an ethyl group, a propyl group, an n-butyl group, and a tert-butyl group. Can be mentioned.
The cyclic alkyl group for R ⁴⁹ preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, etc., which may or may not be substituted with an alkyl group having 1 to 5 carbon atoms, a fluorine atom or a fluorinated alkyl group, etc. And a group obtained by removing one or more hydrogen atoms from the polycycloalkane. Examples of the monocycloalkane include cyclopentane and cyclohexane. Examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.

As the alkoxycarbonylalkyloxy group in the substituted aryl group, for example,
General formula: —O—R ⁵⁰ —C (═O) —O—R ⁵⁶
[Wherein, R ⁵⁰ represents a linear or branched alkylene group, and R ⁵⁶ represents a tertiary alkyl group. ] Is represented.
The linear or branched alkylene group for R ⁵⁰ preferably has 1 to 5 carbon atoms, such as a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, or a 1,1-dimethylethylene group. Etc.
As the tertiary alkyl group for R ⁵⁶ , 2-methyl-2-adamantyl group, 2-ethyl-2-adamantyl group, 1-methyl-1-cyclopentyl group, 1-ethyl-1-cyclopentyl group, 1-methyl -1-cyclohexyl group, 1-ethyl-1-cyclohexyl group, 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 group; 1- (1-cyclohexyl) -1-methylethyl Group, 1- (1-cyclohexyl) -1-methylpropyl group, 1- (1-cyclohexyl) -1-methylbutyl group, 1- (1-cyclohexyl) -1-methylpentyl group, tert-butyl group, tert -Pentyl group, tert-hexyl group and the like.
Moreover, the general ^formula: the ^{R 56} in the -O-R 50 -C (= O ) -O-R 56, also include groups replaced by ^{R 56} '. R ⁵⁶ ′ is a hydrogen atom, an alkyl group, a fluorinated alkyl group, or an aliphatic cyclic group that may contain a hetero atom.
^Examples of the alkyl group for R ⁵⁶ ′ include the same alkyl groups as those described above for R ⁴⁹ .
^Examples of the fluorinated alkyl group for R ⁵⁶ ′ include groups in which some or all of the hydrogen atoms within the alkyl group for R ⁴⁹ have been substituted with fluorine atoms.
Examples of the aliphatic cyclic group which may contain a hetero atom in R ⁵⁶ ′ include an aliphatic cyclic group containing no hetero atom, an aliphatic cyclic group containing a hetero atom in the ring structure, and an aliphatic cyclic group. Examples include those in which a hydrogen atom in the group is substituted with a heteroatom.
Regarding R ⁵⁶ ′, the aliphatic cyclic group containing no hetero atom includes a group obtained by removing one or more hydrogen atoms from a polycycloalkane such as monocycloalkane, bicycloalkane, tricycloalkane, tetracycloalkane, and the like. Can be mentioned. Examples of the monocycloalkane include cyclopentane and cyclohexane. Examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
Specific examples of the aliphatic cyclic group containing a hetero atom in the ring structure for R ⁵⁶ ′ include groups represented by the following formulas (L1) to (L6) and (S1) to (S4). It is done.
As for R ⁵⁶ ′, the hydrogen atom in the aliphatic cyclic group is specifically substituted with a hetero atom, specifically, the hydrogen atom in the aliphatic cyclic group is substituted with an oxygen atom (═O), etc. Is mentioned.

^{-C (= O) -O-R} 6 ', -O-C (= O) -R 7', 'R 6 ^{in' -O-R 8, R 7} ', R 8' are each carbon atoms 1 to 25 linear, branched or cyclic saturated hydrocarbon group having 3 to 20 carbon atoms, or a linear or branched aliphatic unsaturated hydrocarbon group having 2 to 5 carbon atoms. .
The linear or branched saturated hydrocarbon group has 1 to 25 carbon atoms, preferably 1 to 15 carbon atoms, and more preferably 4 to 10 carbon atoms.
Examples of the linear saturated hydrocarbon group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group.
Examples of the branched saturated hydrocarbon group excluding the tertiary alkyl group include, 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, 1-methylpentyl group, 2-methylpentyl group, 3-methylpentyl group, 4-methylpentyl group and the like can be mentioned.
The linear or branched saturated hydrocarbon group may have a substituent. Examples of the substituent include an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, an oxygen atom (═O), a cyano group, and a carboxy group.
As the alkoxy group as a substituent of the linear or branched saturated hydrocarbon 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 and a tert-butoxy group are preferable, and a methoxy group and an ethoxy group are most preferable.
Examples of the halogen atom as a substituent of the linear or branched saturated hydrocarbon group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.
As the halogenated alkyl group as a substituent of the linear or branched saturated hydrocarbon group, part or all of the hydrogen atoms of the linear or branched saturated hydrocarbon group are the halogen atoms. And a group substituted with.
The cyclic saturated hydrocarbon group having 3 to 20 carbon atoms in R ⁶ ′, R ⁷ ′, and R ⁸ ′ may be either a polycyclic group or a monocyclic group. A group in which one hydrogen atom has been removed from a polycycloalkane such as bicycloalkane, tricycloalkane, tetracycloalkane, and the like. More specifically, one hydrogen atom was removed from a monocycloalkane such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane, and a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Group and the like.
The cyclic saturated hydrocarbon group may have a substituent. For example, part of the carbon atoms constituting the ring of the cyclic alkyl group may be substituted with a heteroatom, or the hydrogen atom bonded to the ring of the cyclic alkyl group may be substituted with a substituent. Good.
Examples of the former include one or more hydrogen atoms from a heterocycloalkane in which a part of the carbon atoms constituting the ring of the monocycloalkane or polycycloalkane is substituted with a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. Examples include groups other than atoms. The ring structure may have an ester bond (—C (═O) —O—). Specifically, a lactone-containing monocyclic group such as a group obtained by removing one hydrogen atom from γ-butyrolactone, or a group obtained by removing one hydrogen atom from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring. And other lactone-containing polycyclic groups.
Examples of the substituent in the latter example include the same as those described above as the substituent that the linear or branched alkyl group may have, a lower alkyl group, and the like.
R ⁶ ′, R ⁷ ′, and R ⁸ ′ may be a combination of a linear or branched alkyl group and a cyclic alkyl group.
A combination of a linear or branched alkyl group and a cyclic alkyl group includes a group in which a cyclic alkyl group is bonded as a substituent to a linear or branched alkyl group, and a substituent to the cyclic alkyl group. And a group having a linear or branched alkyl group bonded thereto.
Examples of the linear aliphatic unsaturated hydrocarbon group for R ⁶ ′, R ⁷ ′, and R ⁸ ′ include a vinyl group, a propenyl group (allyl group), and a butynyl group.
Examples of the branched aliphatic unsaturated hydrocarbon group for R ⁶ ′, R ⁷ ′, and R ⁸ ′ include a 1-methylpropenyl group and a 2-methylpropenyl group.
The linear or branched aliphatic unsaturated hydrocarbon group may have a substituent. Examples of the substituent include the same ones as those exemplified as the substituent which the linear or branched alkyl group may have.
Among R ⁷ ′ and R ⁸ ′, among them, the lithography characteristics and the resist pattern shape are good, so that the linear or branched saturated hydrocarbon group having 1 to 15 carbon atoms, or the carbon number 3-20 cyclic saturated hydrocarbon groups are preferred.

The aryl groups for R ¹ ″ to R ³ ″ are each preferably a phenyl group or a naphthyl group.

Examples of the alkyl group for R ¹ ″ to R ³ ″ include a linear, branched, or cyclic alkyl group having 1 to 10 carbon atoms. Especially, it is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.

As an alkenyl group of R < ¹ >"-R< ³ >", it is preferable that it is C2-C10, for example, 2-5 are more preferable, and 2-4 are more preferable. Specific examples include a vinyl group, a propenyl group (allyl group), a butynyl group, a 1-methylpropenyl group, and a 2-methylpropenyl group.
The alkyl group and alkenyl group of R ¹ ″ to R ³ ″ are an alkoxy group, a halogen atom, a hydroxyl group, an oxo group (═O), an aryl group, an alkoxyalkyloxy group, an alkoxycarbonylalkyloxy group, —C (═O). It may be a substituted alkyl group or a substituted alkenyl group substituted with —O—R ⁶ ′, —O—C (═O) —R ⁷ ′, —O—R ⁸ ′ or the like. These substituents are the same as the substituents that the substituted aryl group may have.

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

  Specific examples of the cation moiety in the compound represented by the formula (c-1) include, for example, triphenylsulfonium, (3,5-dimethylphenyl) diphenylsulfonium, (4- (2-adamantoxymethyloxy)- 3,5-dimethylphenyl) diphenylsulfonium, (4- (2-adamantoxymethyloxy) phenyl) diphenylsulfonium, (4- (tert-butoxycarbonylmethyloxy) phenyl) diphenylsulfonium, (4- (tert-butoxycarbonyl) Methyloxy) -3,5-dimethylphenyl) diphenylsulfonium, (4- (2-methyl-2-adamantyloxycarbonylmethyloxy) phenyl) diphenylsulfonium, (4- (2-methyl-2-adamantyloxycarbonylmethyl) Xy) -3,5-dimethylphenyl) diphenylsulfonium, tri (4-methylphenyl) sulfonium, dimethyl (4-hydroxynaphthyl) sulfonium, monophenyldimethylsulfonium, diphenylmonomethylsulfonium, (4-methylphenyl) diphenylsulfonium, 4-methoxyphenyl) diphenylsulfonium, tri (4-tert-butyl) phenylsulfonium, diphenyl (1- (4-methoxy) naphthyl) sulfonium, di (1-naphthyl) phenylsulfonium, 1-phenyltetrahydrothiophenium, 1 -(4-Methylphenyl) tetrahydrothiophenium, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiophenium, 1- (4-methoxynaphthalen-1-yl) Trahydrothiophenium, 1- (4-ethoxynaphthalen-1-yl) tetrahydrothiophenium, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothiophenium, 1-phenyltetrahydrothiopyranium, Examples include 1- (4-hydroxyphenyl) tetrahydrothiopyranium, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothiopyranium, 1- (4-methylphenyl) tetrahydrothiopyranium, and the like.

  Specific examples of the cation moiety in the compound represented by the formula (c-1) include those shown below.

［式中、ｇ１は繰返し数を示し、１〜５の整数である。］

[Wherein g1 represents the number of repetitions and is an integer of 1 to 5. ]

［式中、ｇ２、ｇ３は繰返し数を示し、ｇ２は０〜２０の整数であり、ｇ３は０〜２０の整数である。］

[Wherein g2 and g3 represent the number of repetitions, g2 is an integer of 0 to 20, and g3 is an integer of 0 to 20. ]

In Formula (I-1-34), R ⁰¹ is an arylene group or an alkylene group, R ⁰² and R ⁰³ are each independently an aryl group or an alkyl group, and R ⁰² and R ⁰³ are bonded to each other to form a compound A ring may be formed together with the sulfur atom therein, and at least one of R ^{01 to} R ⁰³ is an arylene group or an aryl group, W ¹ is an n-valent linking group, and n is 2 or 3 It is.
The arylene group R ^01, not particularly limited, for example, an arylene group having 6 to 20 carbon atoms, said arylene groups, part or all of the hydrogen atoms, those may be substituted The alkylene group for R ⁰¹ is not particularly limited, and examples thereof include linear, branched or cyclic alkylene groups having 1 to 10 carbon atoms.
The aryl group for R ⁰² and R ⁰³ is not particularly limited, and may be, for example, an aryl group having 6 to 20 carbon atoms, and the aryl group may have part or all of its hydrogen atoms substituted. There are no particular restrictions on the alkyl group of R ⁰² and R ⁰³ , and examples include linear, branched or cyclic alkyl groups having 1 to 10 carbon atoms.
Examples of the divalent linking group for W ¹ include those similar to the divalent linking group for Y ^{2 in} the above formula (a1-0-2), which may be linear, branched, or cyclic. It may be, and it is preferable that it is cyclic. Of these, a group in which two carbonyl groups are combined at both ends of the arylene group is preferable.
The trivalent linking group for W ¹ is preferably a group in which three carbonyl groups are combined with an arylene group.

In formula (c-2), R ⁵ ″ to R ⁶ ″ each independently represents an aryl group, alkyl group or alkenyl group which may have a substituent.
At least one of R ⁵ ″ to R ⁶ ″ represents an aryl group. Any of R ⁵ ″ to R ⁶ ″ is preferably an aryl group.
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 ″.
Examples of the alkenyl group for R ⁵ ″ to R ⁶ ″ include the same alkenyl groups for R ¹ ″ to R ³ ″.
Among these, it is most preferable that all of R ⁵ ″ to R ⁶ ″ are phenyl groups.
Specific examples of the cation moiety represented by the formula (b1-c2) include diphenyliodonium and bis (4-tert-butylphenyl) iodonium.

Moreover, as a suitable thing of the organic cation of Z ^<+> , what is represented by (I-2)-(I-5) is mentioned, for example.

In formulas (I-2) to (I-5), u is an integer of 1 to 3, and 1 or 2 is most preferable.
In formulas (I-2) to (I-4), R ^{6a to} R ^8a are an alkylene group which may have a substituent or a phenylene group which may have a substituent, and R ^{6b to} R ^8b is a hydrogen atom, an alkyl group which may have a substituent, a phenyl group or an naphthyl group which may have a substituent.
In formula (I-5), R ⁹ represents an alkyl group which may have a substituent, a phenyl group which may have a substituent, or a naphthyl group.

The alkylene group for R ^{6a to} R ^8a is preferably a linear or branched alkylene group. 1-12 are preferable, as for carbon number of this alkylene group, 1-5 are more preferable, 1-3 are more preferable, and 1 or 2 is especially preferable.
Examples of the substituent that the alkylene group may have include an alkoxy group, a halogen atom, a hydroxyl group, an oxo group (═O), a cyano group, an aryl group, an alkoxyalkyloxy group, an alkoxycarbonylalkyloxy group, —C ( ═O) —O—R ⁷ ″, —O—C (═O) —R ⁸ ″, —O—R ⁹ ″ and the like. Alkoxy group, halogen atom, aryl group, alkoxyalkyloxy group, alkoxycarbonyl As the alkyloxy group, —C (═O) —O—R ⁷ ″, —O—C (═O) —R ⁸ ″, —O—R ⁹ ″, R ¹ in the above formula (c-1) is used. In the description of “˜R ³ ”, the same as those described as the substituent that the substituted aryl group may have.
In the formula, as the alkyl group which may have a substituent in R ^{6b to} R ^8b and R ^9, the substituted alkyl exemplified in the description of R ¹ ″ to R ³ ″ in the general formula (c-1) The same thing as a group is mentioned.
Examples of the substituent that the phenyl group or naphthyl group in R ^{6b to} R ^8b and R ⁹ may have include the substituted aryl described in the description of R ¹ ″ to R ³ ″ in the general formula (c-1). The thing similar to what was mentioned as a substituent which group may have is mentioned.
Preferable examples of the cation represented by the formulas (I-2) to (I-4) include those shown below. In the formula, R ^C represents a substituent (alkoxy group, alkoxyalkyloxy group, alkoxycarbonylalkyloxy group, halogen atom, hydroxyl group, oxo group (═O), aryl group exemplified in the description of the substituted aryl group. , —C (═O) —O—R ⁶ ′, —O—C (═O) —R ⁷ ′, —O—R ⁸ ′).
Specific examples are shown below.

Moreover, as a suitable thing of the organic cation of Z ^<+>, the cation represented by the following general formula (I-6) or general formula (I-7) is mentioned, for example.

［式中、Ｒ^４０は水素原子またはアルキル基であり、Ｒ^４１はアルキル基、アセチル基、カルボキシ基、またはヒドロキシアルキル基であり、Ｒ^４２〜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、またはヒドロキシアルキル基であり；ｎ_０〜ｎ_５はそれぞれ独立して０〜３の整数であり、ただし、ｎ_０＋ｎ_１は５以下であり、ｎ_６は０〜２の整数である。］

[Wherein, R ⁴⁰ represents a hydrogen atom or an alkyl group, R ⁴¹ represents an alkyl group, an acetyl group, a carboxy group, or a hydroxyalkyl group, and R ^{42 to} R ⁴⁶ each independently represents an alkyl group, an acetyl group, An alkoxy group, a carboxy group, or a hydroxyalkyl group; n _{0 to} n ₅ are each independently an integer of 0 to 3, provided that n ₀ + n ₁ is 5 or less and n ₆ is 0 to 2 It is an integer. ]

In general formula (I-6), the alkyl group of R ⁴⁰ is preferably an alkyl group having 1 to 15 carbon atoms, more preferably an alkyl group having 1 to 10 carbon atoms, and still more preferably an alkyl group having 4 to 10 carbon atoms. Of these, a linear or branched alkyl group is particularly preferred.
In R ^{41 to} R ⁴⁶ in the general formula (I-6) or (I-7), the alkyl group is preferably an alkyl group having 1 to 5 carbon atoms, and more preferably a linear or branched alkyl group. A methyl group, an ethyl group, a propyl group, an isopropyl group, an n-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 code n ₀ attached to the OR ⁴⁰ is an integer of 2 or more, the plurality of OR ⁴⁰ may be the same or different.
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 ₀ is preferably 0 or 1.
n ₁ is preferably 0-2.
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.

  Preferable examples of the organic cation represented by the formula (I-5) or the formula (I-6) include those shown below.

  Among the above, as the component (B1), the compound represented by the following general formula (b1-1-0) is particularly preferable because the lithography characteristics and the resist pattern shape are better when the resist composition is used. preferable.

［式中Ｘ、Ｚ^＋は、前記式（ｂ１−１）と同様であり、Ｒ^２aは炭素数１〜８のアルキル基であり、Ｒ^３aは炭素数１〜５のフッ素化アルキル基であり、ｖ１は１〜5の整数である。ｖ２は０〜４の整数である。Ｚ^＋は有機カチオンである。］

[Wherein X and Z ⁺ are the same as those in the formula (b1-1), R ^2a is an alkyl group having 1 to 8 carbon atoms, and R ^3a is a fluorinated alkyl group having 1 to 5 carbon atoms. , V1 is an integer of 1-5. v2 is an integer of 0-4. Z ⁺ is an organic cation. ]

In the formula (b1-1-0), R ^2a is preferably the same as R ″ described above for R ² .
In the formula (b1-1-0), R ^3a is preferably one having 5 or less carbon atoms among those exemplified for R ³ . The fluorinated alkyl group, _{e.g., -CF 3, -CF 2 CF 3} , -CF 2 CF 2 CF 3, -CF (CF 3) CF 3, -CF 2 CF 2 CF 2 CF 3, -CF (CF _{3) CF 2 CF 3, -CF} 2 CF (CF 3) CF 3, -C (CF 3) 2 CF 3, -CF (CF 2 CF 3) CF 3, -CH 2 CF 3, -CH 2 CH 2 CF ₃ —, —CH ₂ CF ₂ CF _3, —CH ₂ CH ₂ CH ₂ CF ₃ , —CH ₂ CH ₂ CF ₂ CF ₃ , —CH ₂ CF ₂ CF ₂ CF ₂ — and the like can be mentioned. Among these, —CF ₃ , —CF ₂ CF ₃ , —CF ₂ CF ₂ CF ₃ , —CH ₂ CF ₂ CF ₃ , or is preferable, —CF ₃ , —CF ₂ CF _3, or —CH ₂ CH ₂ CF ₃ is more preferable, and —CF ₃ is particularly preferable.

  Specific examples of the general formula (b1-1-0) include the following (b1-1-2) to (b1-1-7).

The component (B1) may be synthesized by a conventional method, or a commercially available product may be used.
As the component (B1), one type may be used alone, or two or more types may be used in combination.
It is preferable that the content rate of (B1) component in the resist composition of this invention exists in the range of 0.5-50 mass parts with respect to 100 mass parts of (A) component, and 0.5-40 mass parts More preferably, it is in the range of 1 to 30 parts by mass.
When the resist composition is above the lower limit of the above range, the lithography properties are further improved. It is preferable for it to be not more than the upper limit of the above range, since a uniform solution can be obtained and the storage stability becomes good.
In the component (B), the proportion of the component (B1) is preferably 20% by mass or more, more preferably 40% by mass or more, and may be 100% by mass with respect to the total mass of the component (B). Most preferably, it is 70-100 mass%. When the content ratio of the component (B1) is not less than the lower limit of the above range, the lithography properties are further improved when a resist composition is obtained. Further, a better resist pattern shape can be obtained.

[(B2) component]
The resist composition of the present invention may contain an acid generator other than the component (B1) (hereinafter referred to as “component (B2)”) as the component (B) as necessary.
The component (B2) is not particularly limited as long as it does not correspond to the component (B1). Until now, onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyls Also known are a variety of diazomethane acid generators such as bisarylsulfonyldiazomethanes and poly (bissulfonyl) diazomethanes, nitrobenzyl sulfonate acid generators, iminosulfonate acid generators, and disulfone acid generators. Yes.

  As the onium salt acid generator not corresponding to the component (B1), for example, a compound in which the anion moiety in the (b1-1) is replaced with an anion moiety represented by the following general formula (b-1) is used. it can.

［式中、Ｒ^４”は、置換基を有していてもよい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す。］

[Wherein R ⁴ ″ represents a halogenated alkyl group, an aryl group, or an alkenyl group which may have a substituent.]

In formula (b-1), R ⁴ ″ represents a halogenated alkyl group which may have a substituent, an aryl group which may have a substituent, or an alkenyl which may have a substituent. Represents a group.
Examples of the halogenated alkyl group for R ⁴ ″ include groups in which part or all of the hydrogen atoms of a linear, branched, or cyclic alkyl group have been substituted with halogen atoms. An atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
When the alkyl group in the halogenated alkyl group is a linear or branched alkyl group, the alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and 1 carbon atom. It is most preferable that when it is a cyclic alkyl group, it is preferably 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms. 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 ″, “may have a substituent” 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, a formula: X ³ -Q ^3- [wherein Q ³ is a divalent linking group containing an oxygen atom, and X ³ represents a substituent. It is a C3-C30 hydrocarbon group which may have. ] Etc. which are represented by these.
Examples of the halogen atom and alkyl group include the same groups as those described as the halogen atom and alkyl group in the halogenated alkyl group in R ⁴ ″.
Examples of the hetero atom include an oxygen atom, a nitrogen atom, and a sulfur atom.

In the group represented by X ³ -Q ^3- , Q ³ is a divalent linking group containing an oxygen atom.
Q ³ may contain atoms other than oxygen atoms. Examples of atoms other than oxygen atoms include carbon atoms, hydrogen atoms, oxygen atoms, sulfur atoms, and nitrogen atoms.
Examples of the divalent linking group containing an oxygen atom include an oxygen atom (ether bond; —O—), an ester bond (—C (═O) —O—), and an amide bond (—C (═O) —NH. -), A carbonyl group (-C (= O)-), a non-hydrocarbon oxygen atom-containing linking group such as a carbonate bond (-O-C (= O) -O-); the non-hydrocarbon oxygen atom Examples include a combination of a containing linking group and an alkylene group.
Examples of the combination include —R ⁹¹ —O—, —R ⁹² —O—C (═O) —, —C (═O) —O—R ⁹³ —O—C (═O) — , R ^{91 to} R ⁹³ are the same as described above, and each independently represents 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.
Q ² is preferably a divalent linking group containing an ester bond or an ether bond, and among them, —R ⁹¹ —O—, —R ⁹² —O—C (═O) — or —C (═O) — O—R ⁹³ —O—C (═O) — is preferred.

In the group represented by X ³ -Q ^3- , the hydrocarbon group of X ³ may be an aromatic hydrocarbon group or an aliphatic hydrocarbon group.

X ³ is preferably a cyclic group which may have a substituent. The cyclic group may be an aromatic hydrocarbon group which may have a substituent, an aliphatic cyclic group which may have a substituent, or a substituent. It is preferably an aliphatic cyclic group that may be used.
The aromatic hydrocarbon group is preferably a naphthyl group which may have a substituent or a phenyl group which may have a substituent.
As the aliphatic cyclic group which may have a substituent, a polycyclic aliphatic cyclic group which may have a substituent is preferable. The polycyclic aliphatic cyclic group is a group obtained by removing one or more hydrogen atoms from the polycycloalkane, and is represented by the formulas (L2) to (L5) and (S3) to (S4). Groups and the like are preferred.

In the present invention, R ⁴ ″ preferably has X ³ -Q ³ — as a substituent. In this case, R ⁴ ″ can be X ³ -Q ³ -Y ^3- [wherein Q ³ and X ^{3 3} is the same as above, and Y ³ 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.
X ³ -Q ³ -Y ³ - In the group represented by the formula, the alkylene group of ^{Y 3,} preferably from 1 to 4 carbon atoms.
Examples of the fluorinated alkylene group for Y ³ include groups in which some or all of the hydrogen atoms of the alkylene group have been substituted with fluorine atoms.

Y ³ is preferably a fluorinated alkylene group, and more preferably —CF ₂ —, —CF ₂ CF ₂ — or —CF ₂ CF ₂ CF ₂ —.

Examples of the anion moiety having a group represented by X ³ -Q ³ —Y ³ — include an anion moiety represented by any of the following formulas (b1) to (b8).

［式中、ｚ０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、ｔ３は１〜３の整数であり、ｒ１〜ｒ２はそれぞれ独立に０〜３の整数であり、ｉは１〜２０の整数であり、Ｒ^７は置換基であり、ｍ１〜ｍ５はそれぞれ独立に０または１であり、ｖ０〜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の整数であり、Ｑ”は前記と同じである。］

[In the formula, z0 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, t3 is an integer of 1 to 3, and r1 ~r2 are each independently an integer of 0 to 3, i is an integer of 1 to 20, ^{R 7} represents a substituent, m1 to m5 are each independently 0 or 1, v0~v5 each Each independently represents an integer of 0 to 3, w1 to w5 are each independently an integer of 0 to 3, and Q ″ is the same as defined above.]

Examples of the substituent for R ⁷ include an alkyl group, an alkoxy group, a halogen atom, a halogenated alkyl group, a hydroxyl group, and an oxygen atom (═O).
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.

  Moreover, the onium salt type acid generator which replaced the anion part by the anion represented by the following general formula (b-3) or (b-4) can also be used.

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

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

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

  (B2) A component may be used individually by 1 type and may be used in combination of 2 or more type.

  0.5-50 mass parts is preferable with respect to 100 mass parts of (A) component, and, as for content of the (B) component whole in the resist composition of this invention, 1-40 mass parts is more preferable. By setting it within the above range, pattern formation is sufficiently performed. Moreover, since a uniform solution is obtained and storage stability becomes favorable, it is preferable.

<Optional component>
[(D) component]
In the resist composition of the present invention, a nitrogen-containing organic compound component (D) (hereinafter referred to as “(D)” which does not fall under the components (A) and (B), as long as the effects of the present invention are not impaired. Component ")).
As the component (D), an acid diffusion control agent, that is, a substance that acts as a quencher that traps the acid generated from the component (A) or the components (A) and (B) by exposure is particularly effective. The present invention is not limited, and a wide variety of products have already been proposed. Examples thereof include amines such as aliphatic amines and aromatic amines, among which aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are preferred.
An aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 20 carbon atoms.
Examples of the aliphatic amine include amines (alkyl amines or alkyl alcohol amines) or cyclic amines in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 1 to 20 carbon atoms. It is done.
The alkyl group and the alkyl group in the hydroxyalkyl group may be linear, branched or cyclic.
When the alkyl group is linear or branched, the carbon number thereof is more preferably 2-20, and further preferably 2-8.
When the alkyl group is cyclic (when it is a cycloalkyl group), the carbon number is preferably 3 to 30, more preferably 3 to 20, still more preferably 3 to 15, and 4 to 12 carbon atoms. It is particularly preferred that the number of carbon atoms is 5-10. The alkyl group may be monocyclic or polycyclic. Specific examples include groups in which one or more hydrogen atoms have been removed from monocycloalkane, groups in which one or more hydrogen atoms have been removed from polycycloalkanes such as bicycloalkane, tricycloalkane, and tetracycloalkane. . Specific examples of the monocycloalkane include cyclopentane and cyclohexane. Specific examples of the polycycloalkane include adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane.
Specific examples of the alkylamine include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di-n- Dialkylamines such as heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-pentylamine, tri-n-hexylamine, tri- Examples include trialkylamines such as n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, and tri-n-dodecylamine.
Specific examples of the alkyl alcohol amine include diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, di-n-octanolamine, tri-n-octanolamine, stearyl diethanolamine, lauryldiethanolamine and the like.
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-hydroxyethoxy) ) Ethoxy} ethyl] amine and the like.
Examples of the aromatic amine include aniline, pyridine, 4-dimethylaminopyridine, pyrrole, indole, pyrazole, imidazole or derivatives thereof, diphenylamine, triphenylamine, and tribenzylamine.
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.

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

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

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

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

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

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

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

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

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

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

[(S) component]
The resist composition can be produced by dissolving the components blended in the resist composition in an organic solvent (hereinafter 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.
(S) component is, for example, lactones such as γ-butyrolactone; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl-n-pentyl ketone, methyl isopentyl ketone, 2-heptanone; ethylene glycol, diethylene glycol, propylene glycol, Polyhydric alcohols such as dipropylene glycol; compounds having an ester bond such as ethylene glycol monoacetate, diethylene glycol monoacetate, propylene glycol monoacetate, dipropylene glycol monoacetate, the polyhydric alcohols or compounds having the ester bond Monoalkyl ethers such as monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, or monophenyl ether Derivatives of polyhydric alcohols such as compounds having an ether bond such as propylene glycol monomethyl ether acetate (PGMEA) and propylene glycol monomethyl ether (PGME) among these; cyclic ethers such as dioxane, , Methyl lactate, ethyl lactate (EL), methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, ethyl pyruvate, methyl methoxypropionate, ethyl ethoxypropionate, etc .; anisole, ethyl benzyl ether, cresyl methyl Ether, diphenyl ether, dibenzyl ether, phenetole, butyl phenyl ether, ethylbenzene, diethylbenzene, pentylbenzene, isopropylbenzene, toluene, xylene, cymene, mesitylene An aromatic organic solvent such as

(S) A component may be used independently and may be used as 2 or more types of mixed solvents.
Of these, γ-butyrolactone, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), and ethyl lactate (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, and is preferably in the range of 1: 9 to 9: 1. 2: 8 to 8: A range of 2 is more preferable.
More specifically, when EL is blended as a polar solvent, the mass ratio of PGMEA: EL is preferably 1: 9 to 9: 1, more preferably 2: 8 to 8: 2. Moreover, when mix | blending PGME as a polar solvent, the mass ratio of PGMEA: PGME becomes like this. Preferably it is 1: 9-9: 1, More preferably, it is 2: 8-8: 2, More preferably, it is 3: 7-7: 3.
In addition, as the component (S), a mixed solvent of at least one selected from PGMEA and EL and γ-butyrolactone is also preferable. In this case, the mixing ratio of the former and the latter is preferably 70:30 to 95: 5.
Furthermore, as the component (S), a mixed solvent of PGMEA and cyclohexanone or a mixed solvent of PGMEA, PGME and cyclohexanone is also preferable. In this case, the mixing ratio of the former is preferably PGMEA: cyclohexanone = 95-5: 10-90, and the mixing ratio of the latter is preferably PGMEA: PGME: cyclohexanone = 35-55. : 25-45: 10-30.

  As described above, the component (B1) used in the resist composition of the present invention is a novel one that has not been conventionally known. By including the component (B1) as the component (B), the resist composition of the present invention improves various lithography characteristics such as LWR, EL margin, MEEF, and the resist pattern shape. The reason why the above effect is obtained is not clear, but is considered as follows.

  The component (B1) of the present invention has both a portion where the skeleton is branched and becomes bulky as a whole, and a chain-like portion, so that the acid generated in the exposed portion is uniformly diffused, and the entire exposed portion is sufficiently base. Changes in the solubility of the material components occur. As a result, it is considered that the throughput is improved while the lithography characteristics are achieved as described above.

Further, in the component (B1) of the present invention, a super strong acid is generated by exposure because a fluorine atom is bonded to a carbon atom bonded to SO ₃ ^— . Therefore, in the exposed area, the polarity of the base material component can be increased by the action of acid, and the progress of cross-linking between the base material component and the cross-linking agent component by the action of acid can be further promoted, and the resolution and lithography properties can be improved. It is thought that it leads to.

≪Resist pattern formation method≫
Using the resist composition as described above, a resist pattern can be formed by, for example, the following resist pattern forming method.
First, the resist composition is coated on a support with a spinner or the like, and pre-baked (post-apply bake (PAB)) for 40 to 120 seconds, preferably 60 to 90 seconds under a temperature condition of 80 to 150 ° C. After, for example, an electron beam (EB) is selectively exposed through a desired mask pattern by an electron beam drawing machine or the like, and then subjected to PEB (post-exposure heating) for 40 to 120 seconds under a temperature condition of 80 to 150 ° C. Preferably, it is applied for 60 to 90 seconds. Next, this is developed.
In the case of an alkali development process, an alkali development treatment is performed using an alkali developer, for example, a 0.1 to 10% by mass tetramethylammonium hydroxide (TMAH) aqueous solution.
In the case of a solvent development process, development processing is performed using an organic solvent. The organic solvent is not particularly limited as long as it can dissolve the component (A) (component (A) before exposure), and can be appropriately selected from known organic solvents. Specific examples include ketone solvents, ester solvents, alcohol solvents, amide solvents, ether solvents, and other polar solvents, hydrocarbon solvents, and the like, with ester solvents being preferred. As the ester solvent, butyl acetate is preferred.
A rinsing treatment is preferably performed after the development treatment. In the case of an alkali development process, water rinsing using pure water is preferable. In the case of the solvent development process, it is preferable to use a rinse solution containing the organic solvent mentioned above.
Thereafter, drying is performed. 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 of the present invention is more effective for KrF excimer laser, ArF excimer laser, EB or EUV, and particularly effective for ArF excimer laser.

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

[Example 1, Comparative Examples 1-3]
Each component shown in Table 1 was mixed and dissolved to prepare a resist composition.

Each abbreviation in Table 1 has the following meaning. Moreover, the numerical value in [] is a compounding quantity (mass part).
(A) -1: the following polymer compound (1) (mass average molecular weight; Mw = 7000, dispersity: Mw / Mn = 1.65, l / m / n = 40/40/20 (molar ratio))
(A) -2: the following polymer compound (2) (mass average molecular weight; Mw = 7000, dispersity: Mw / Mn = 1.68, l / m / n = 40/40/20 (molar ratio))
(B) -1: The following compound (B-1). (Manufactured by Central Glass Co., Ltd.)
(B) -2: The following compound (B-2).
(D) -1: tri-n-pentylamine.
(F) -1: the following polymer compound (F) -1 (mass average molecular weight; Mw = 18000, dispersity: Mw / Mn = 1.5, l / m = 80/20 (molar ratio)).
(S) -1: Mixed solvent of PGMEA / PGME / cyclohexane = 45/30/25 (mass ratio).

  Using the obtained resist composition, a resist pattern was formed according to the following procedure, and the following evaluations were performed.

[Formation of resist pattern]
An organic antireflection film composition “ARC29A” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto a 12-inch silicon wafer using a spinner, and baked on a hot plate at 205 ° C. for 90 seconds to be dried. Thereby, an organic antireflection film having a thickness of 90 nm was formed.
Then, the resist composition of each example is applied onto the organic antireflection film using a spinner, prebaked (PAB) at a hot plate temperature of 105 ° C. for 60 seconds, and dried. A resist film having a thickness of 100 nm was formed.
Next, an ArF excimer laser was used with an ArF immersion exposure apparatus NSR-S609B (manufactured by Nikon Corporation; NA (numerical aperture) = 1.07, Dipole (in / out: 0.78 / 0.97), w / POLANO). (193 nm) was selectively irradiated through a mask pattern (6% halftone).
Then, a post-exposure heating (PEB) treatment at 90 ° C. for 60 seconds was performed, and a 2.38 mass% tetramethylammonium hydroxide (TMAH) aqueous solution “NMD-3” (trade name, Tokyo Ohka Kogyo Co., Ltd.) at 23 ° C. Manufactured for 10 seconds, rinsed with pure water for 15 seconds, and shaken and dried.
Subsequently, post-baking was performed on a hot plate at 100 ° C. for 60 seconds.
As a result, in each example, a 1: 1 line and space (LS) pattern having a line width of 49 nm and a pitch of 98 nm was formed.
The optimum exposure dose Eop (mJ / cm ² ; sensitivity) for forming the LS pattern was determined. The results are also shown in Table 2.

[LWR (line width roughness) evaluation]
In the LS pattern with a line width of 49 nm and a pitch of 98 nm formed by the Eop, the line width was changed to the line width by a length measurement SEM (scanning electron microscope, acceleration voltage 300 V, trade name: S-9380, manufactured by Hitachi High-Technologies Corporation). 400 points were measured in the longitudinal direction, and a triple value (3s) of the standard deviation (s) was obtained from the result, and a value averaged for 3s at 400 points was calculated as a scale indicating LWR. The results are shown in Table 2.
A smaller value of 3s means that the roughness of the line width is smaller, and an LS pattern having a more uniform width is obtained.

[MEEF evaluation]
At the above Eop, the pitch was fixed (in this case, fixed at 98 nm for a 49 nm LS pattern), the target size of the line pattern was changed in 1 nm increments, and LS patterns of 11 points in total were formed. At this time, the target size (nm) is plotted on the horizontal axis (43 to 53 nm in this case), and the pattern dimension (nm) formed on the resist film using each mask pattern is plotted on the vertical axis. The slope was calculated as MEEF. MEEF (straight line) means that the closer the value is to 1, the better the mask reproducibility.

[Exposure margin (EL margin) evaluation]
The exposure amount when the line of the LS pattern is formed within the range of ± 5% (46.5 nm to 51.5 nm) of the target dimension (line width 49 nm) with the optimum exposure amount Eop is obtained. (Unit:%) was determined.
EL margin (%) = (| E1-E2 | / Eop) × 100
E1: Exposure amount (mJ / cm ² ) when an LS pattern having a line width of 46.5 nm was formed
E2: exposure amount (mJ / cm ² ) when an LS pattern having a line width of 51.5 nm was formed
Note that the larger the value of the EL margin, the smaller the change amount of the pattern size accompanying the change in the exposure amount.

  From the results in Table 2, it was confirmed that the resist composition of Example 1 was superior in lithography properties such as LWR and MEEF as compared with the resist compositions of Comparative Examples 1 to 3.

Claims (3)

A resist composition containing a base material component (A) whose solubility in a developing solution is changed by the action of an acid, and an acid generator component (B) that generates an acid upon exposure,
The base material component (A) contains a resin component (A1) having a structural unit (a2) containing a —SO ₂ -containing cyclic group,
The said acid generator component (B) contains the acid generator (B1) which consists of a compound represented by the following general formula (b1-1), The resist composition characterized by the above-mentioned.

[X is an optionally substituted hydrocarbon group having 1 to 15 carbon atoms, R ² is an optionally substituted hydrocarbon group having 1 to 10 carbon atoms, and R ³ Is a fluorinated alkyl group, v1 is an integer of 1 to 5, and v2 is an integer of 0 to 4. Z ⁺ is an organic cation. ]   The resist composition according to claim 1, wherein the resin component (A1) further has a structural unit (a1) containing an acid-decomposable group whose polarity is increased by the action of an acid.   A step of forming a resist film on the support using the resist composition according to claim 1, a step of exposing the resist film, and a step of developing the resist film to form a resist pattern are included. Resist pattern forming method.