JP5276805B2 - Resist composition and resist pattern forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resist composition and a resist pattern forming method, which attains an excellent MEF. <P>SOLUTION: This resist composition contains a base material component A with solubility varying to an alkaline developer by an action of an acid, and an acid generator component B of generating an acid by exposure, and the acid generator component B contains an acid generator component B1 having no acid-dissociable group containing group, and an acid generator component B2 having an acid-dissociable group containing group. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

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

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

  Resist materials are required to have lithography characteristics such as sensitivity to these exposure light sources and resolution capable of reproducing a pattern with fine dimensions. As a resist material that satisfies these requirements, a chemical amplification containing a base material component that has film-forming ability and changes in solubility in an alkaline developer by the action of an acid, and an acid generator that generates an acid upon exposure. Type resist composition is used. For example, a positive chemically amplified resist composition contains a base component whose solubility in an alkaline developer is increased by the action of an acid, and an acid generator. When a resist film formed using such a resist composition is exposed, an acid is generated from the acid generator in the exposed portion, and the solubility of the base component in an alkaline developer is increased by the action of the acid. The exposed part becomes soluble in an alkaline developer.

Until now, resin (base resin) has been mainly used as the base resin for chemically amplified resists. For example, as a resist base resin used in KrF excimer laser (248 nm) lithography, polyhydroxystyrene (PHS) or a resin (PHS resin) in which the hydroxyl group is protected with an acid dissociable, dissolution inhibiting group is used. Yes. In addition, as a resist base resin used in ArF excimer laser (193 nm) lithography or the like, a resin (acrylic resin) having a structural unit derived from (meth) acrylic acid ester in its main chain is generally used. ing. In the case of the positive type, as such a resin, a resin having a structural unit derived from a (meth) acrylic acid ester containing an acid dissociable, dissolution inhibiting group is mainly used (for example, see Patent Documents 1 and 2).
The “(meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position. “(Meth) acrylate” means one or both of an acrylate having a hydrogen atom bonded to the α-position and a methacrylate having a methyl group bonded to the α-position. “(Meth) acrylic acid” means one or both of acrylic acid having a hydrogen atom bonded to the α-position and methacrylic acid having a methyl group bonded to the α-position.

On the other hand, various acid generators used in chemically amplified resists have been proposed so far, such as onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, Diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators and the like are known. Currently, an onium salt acid generator having an onium ion such as triphenylsulfonium in the cation portion is used as the acid generator. The anion moiety of the onium salt acid generator is generally an alkyl sulfonate ion or a fluorinated alkyl sulfonate ion in which part or all of the hydrogen atoms of the alkyl group are substituted with fluorine atoms (for example, Patent Documents). 3).
Japanese Patent No. 2881969 JP 2003-241385 A JP 2003-167347 A

In recent years, the miniaturization of resist patterns has further progressed, and as the demand for high resolution has further increased, various improvements in lithography properties have been demanded. For example, improvement in mask reproducibility when a resist pattern is formed becomes more important as the pattern becomes finer.
One index indicating mask reproducibility is a mask error factor (MEF). The MEF is a parameter indicating how faithfully a mask pattern having a different line width or aperture can be reproduced with the same exposure amount when the pitch is fixed.
This invention is made | formed in view of the said situation, Comprising: It aims at providing the resist composition and the resist pattern formation method which can achieve outstanding MEF.

［式中、Ｒ ^５０ は直鎖状もしくは分岐鎖状のアルキレン基であり、Ｒ ^５１ は酸解離性基である。Ｒ ^５７ およびＲ ^５８ は、それぞれ独立に、水素原子またはアルキル基であり、Ｒ ^５９ はアルキル基であり、Ｒ ^５８ の末端とＲ ^５９ の末端とが相互に結合して環を形成していてもよい。］
本発明の第二の態様は、酸の作用によりアルカリ現像液に対する溶解性が変化する基材成分（Ａ）、および露光により酸を発生する酸発生剤成分（Ｂ）を含有するレジスト組成物であって、
前記基材成分（Ａ）が、酸の作用によりアルカリ現像液に対する溶解性が増大する樹脂成分（Ａ１）を含有し、該樹脂成分（Ａ１）が、酸解離性溶解抑制基を含むアクリル酸エステルから誘導される構成単位（ａ１）と、極性基含有脂肪族炭化水素基を含むアクリル酸エステルから誘導される構成単位（ａ３）を有し、
前記酸発生剤成分（Ｂ）が、酸解離性基含有基を有さない酸発生剤成分（Ｂ１）と、酸解離性基含有基を有する酸発生剤成分（Ｂ２）とを含有し、
前記酸解離性基含有基が、下記一般式（Ｉ−１）または（Ｉ−２）で表される基であることを特徴とするレジスト組成物である。

［式中、Ｒ ^５０ は直鎖状もしくは分岐鎖状のアルキレン基であり、Ｒ ^５１ は酸解離性基である。Ｒ ^５７ およびＲ ^５８ は、それぞれ独立に、水素原子またはアルキル基であり、Ｒ ^５９ はアルキル基であり、Ｒ ^５８ の末端とＲ ^５９ の末端とが相互に結合して環を形成していてもよい。］
本発明の第三の態様は、前記第一の態様又は第二の態様のレジスト組成物を用いて支持体上にレジスト膜を形成する工程、前記レジスト膜を露光する工程、および前記レジスト膜をアルカリ現像してレジストパターンを形成する工程を含むレジストパターン形成方法である。 In order to achieve the above object, the present invention employs the following configuration.
That is, the first aspect of the present invention is a resist composition comprising a base material component (A) whose solubility in an alkaline developer is changed by the action of an acid, and an acid generator component (B) that generates an acid upon exposure. A thing,
The base material component (A) contains a resin component (A1) whose solubility in an alkaline developer is increased by the action of an acid, and the resin component (A1) contains an acid dissociable, dissolution inhibiting group. And a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group,
The acid generator component (B) contains an acid generator component (B1) having no acid dissociable group-containing group and an acid generator component (B2) having an acid dissociable group-containing group ,
In the resist composition, the acid-dissociable group-containing group is a group represented by the following general formula (I-1) or (I-2) .

[Wherein, R ⁵⁰ represents a linear or branched alkylene group, and R ⁵¹ represents an acid dissociable group. R ⁵⁷ and R ⁵⁸ are each independently a hydrogen atom or an alkyl group, R ⁵⁹ is an alkyl group, and the end of R ^{58 and} the end of R ⁵⁹ may be bonded to each other to form a ring. Good. ]
The second aspect of the present invention is a resist composition containing a base component (A) whose solubility in an alkaline developer is changed by the action of an acid, and an acid generator component (B) that generates an acid upon exposure. There,
The base material component (A) contains a resin component (A1) whose solubility in an alkaline developer is increased by the action of an acid, and the resin component (A1) contains an acid dissociable, dissolution inhibiting group. A structural unit derived from (a1), and a structural unit derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group (a3),
The acid generator component (B) contains an acid generator component (B1) having no acid dissociable group-containing group and an acid generator component (B2) having an acid dissociable group-containing group ,
In the resist composition, the acid-dissociable group-containing group is a group represented by the following general formula (I-1) or (I-2) .

[Wherein, R ⁵⁰ represents a linear or branched alkylene group, and R ⁵¹ represents an acid dissociable group. R ⁵⁷ and R ⁵⁸ are each independently a hydrogen atom or an alkyl group, R ⁵⁹ is an alkyl group, and the end of R ^{58 and} the end of R ⁵⁹ may be bonded to each other to form a ring. Good. ]
According to a third aspect of the present invention, there is provided a step of forming a resist film on a support using the resist composition of the first aspect or the second aspect, a step of exposing the resist film, and the resist film. This is a resist pattern forming method including a step of forming a resist pattern by alkali development.

In the present specification and claims, the “structural unit” means a monomer unit (monomer unit) constituting a resin component (polymer, copolymer).
The “acid-dissociable group” is an organic group that can be dissociated by the action of an acid generated from the acid generator component (B) by exposure.
“Exposure” is a concept that includes radiation exposure in general.
The “alkyl group” includes linear, branched and cyclic monovalent saturated hydrocarbon groups unless otherwise specified.
“Lower alkyl group” means an alkyl group having 1 to 5 carbon atoms.

  ADVANTAGE OF THE INVENTION According to this invention, the resist composition and resist pattern formation method which can achieve the outstanding MEF can be provided.

≪Resist composition≫
The resist composition of the present invention comprises a base material component (A) whose solubility in an alkaline developer is changed by the action of an acid (hereinafter referred to as (A) component), and an acid generator component that generates an acid upon exposure ( B) (hereinafter referred to as component (B)).
The resist composition of the present invention may be a negative resist composition or a positive resist composition.

<(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.
The organic compound having a molecular weight of 500 or more is largely classified into a low molecular weight organic compound having a molecular weight of 500 or more and less than 2000 (hereinafter referred to as a low molecular compound) and a high molecular weight resin having a molecular weight of 2000 or more (polymer material). Separated. As the low molecular weight compound, a non-polymer is usually used. In the case of a resin (polymer, copolymer), a polystyrene-reduced mass average molecular weight by GPC (gel permeation chromatography) is used as the “molecular weight”. Hereinafter, the term “resin” refers to a resin having a molecular weight of 2000 or more.
As the component (A), a resin whose alkali solubility is changed by the action of an acid can be used, and a low molecular weight material whose alkali solubility is changed by the action of an acid can also be used.

When the resist composition of the present invention is a negative resist composition, as the component (A), a base material component that is soluble in an alkali developer is used, and a crosslinking agent is further added to the negative resist composition.
In such a negative resist composition, when an acid is generated from the component (B) by exposure, the acid acts to cause crosslinking between the base material component and the crosslinking agent, resulting in poor solubility in an alkali developer. To do. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the negative resist composition on the substrate is selectively exposed, the exposed portion turns into poorly soluble in an alkaline developer, while unexposed. Since the portion remains soluble in the alkali developer and does not change, a resist pattern can be formed by alkali development.
As the component (A) of the negative resist composition, a resin that is soluble in an alkali developer (hereinafter referred to as an alkali-soluble resin) is usually used.
As the alkali-soluble resin, a resin having a unit derived from at least one selected from α- (hydroxyalkyl) acrylic acid or a lower alkyl ester of α- (hydroxyalkyl) acrylic acid is a good resist with little swelling. A pattern can be formed, which is preferable. Α- (Hydroxyalkyl) acrylic acid includes acrylic acid in which a hydrogen atom is bonded to the α-position carbon atom to which the carboxy group is bonded, and a hydroxyalkyl group (preferably having 1 carbon atom) in the α-position carbon atom. One or both of [alpha] -hydroxyalkylacrylic acids to which (5) hydroxyalkyl groups) are attached.
As the crosslinking agent, for example, it is usually preferable to use an amino crosslinking agent such as glycoluril having a methylol group or an alkoxymethyl group because a good resist pattern with less swelling can be formed. It is preferable that the compounding quantity of a crosslinking agent 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 positive resist composition, as the component (A), a base material component whose solubility in an alkaline developer is increased by the action of an acid is used. The component (A) is hardly soluble in an alkali developer before exposure. When an acid is generated from the component (B) by exposure, the solubility in the alkali developer is increased by the action of the acid. Therefore, in the formation of the resist pattern, when the resist film obtained by applying the positive resist composition on the substrate is selectively exposed, the exposed portion changes from poorly soluble to soluble in an alkaline developer. On the other hand, since the unexposed portion remains hardly soluble in alkali and does not change, a resist pattern can be formed by alkali development.

In the resist composition of the present invention, the component (A) is preferably a base material component whose solubility in an alkaline developer is increased by the action of an acid. That is, the resist composition of the present invention is preferably a positive resist composition.
The component (A) may be a resin component (A1) (hereinafter also referred to as component (A1)) whose solubility in an alkaline developer is increased by the action of an acid. It may be a low molecular compound (A2) (hereinafter sometimes referred to as the component (A2)) whose solubility in a liquid is increased, or a mixture thereof.
In the present invention, the component (A) preferably contains the component (A1).

[(A1) component]
As the component (A1), resin components (base resins) that are usually used as base components for chemically amplified resists can be used alone or in combination of two or more.
In the present invention, the component (A1) preferably contains a structural unit derived from an acrylate ester.
Here, in the present specification and claims, the “structural unit derived from an acrylate ester” means a structural unit formed by cleavage of an ethylenic double bond of an acrylate ester.
“Acrylic acid esters” include those in which a hydrogen atom is bonded to the carbon atom at the α-position, and those in which a substituent (atom or group other than a hydrogen atom) is bonded to the carbon atom in the α-position. Include concepts. Examples of the substituent include a lower alkyl group and a halogenated lower alkyl group.
Note that the α-position (α-position carbon atom) of a structural unit derived from an acrylate ester means a carbon atom to which a carbonyl group is bonded, unless otherwise specified.
In the acrylate ester, as the lower alkyl group as a substituent at the α-position, specifically, methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, pentyl group, Examples include lower linear or branched alkyl groups such as isopentyl group and neopentyl group.
Specific examples of the halogenated lower alkyl group include groups in which part or all of the hydrogen atoms in the above-mentioned “lower alkyl group as a substituent at the α-position” are 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.
In the present invention, the α-position of the acrylate ester is preferably a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and is a hydrogen atom, a lower alkyl group or a fluorinated lower alkyl group. In view of industrial availability, a hydrogen atom or a methyl group is most preferable.

The component (A1) particularly preferably has a structural unit (a1) derived from an acrylate ester containing an acid dissociable, dissolution inhibiting group.
In addition to the structural unit (a1), the component (A1) preferably further has a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group.
The component (A1) is a structural unit derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group in addition to the structural unit (a1) or in addition to the structural units (a1) and (a2). It is preferable to have (a3).

・ Structural unit (a1)
The acid dissociable, dissolution inhibiting group in the structural unit (a1) has an alkali dissolution inhibiting property that makes the entire component (A1) difficult to dissolve in an alkali developer before dissociation, and dissociates with an acid. This increases the solubility of the entire component in an alkaline developer, and those that have been proposed as acid dissociable, dissolution inhibiting groups for base resins for chemically amplified resists can be used. Generally, a group that forms a cyclic or chain tertiary alkyl ester with a carboxy group in (meth) acrylic acid or the like; an acetal type acid dissociable, dissolution inhibiting group such as an alkoxyalkyl group is widely known. . The “(meth) acrylic acid ester” means one or both of an acrylic acid ester having a hydrogen atom bonded to the α-position and a methacrylic acid ester having a methyl group bonded to the α-position.

Here, the “tertiary alkyl ester” is an ester formed by replacing a hydrogen atom of a carboxy group with a chain or cyclic alkyl group, and the carbonyloxy group (—C (O)). A structure in which the tertiary carbon atom of the chain or cyclic alkyl group is bonded to the terminal oxygen atom of -O-). In this tertiary alkyl ester, when an acid acts, a bond is cut between an oxygen atom and a tertiary carbon atom.
The chain or cyclic alkyl group may have a substituent.
Hereinafter, a group that is acid dissociable by constituting a carboxy group and a tertiary alkyl ester is referred to as a “tertiary alkyl ester type acid dissociable, dissolution inhibiting group” for convenience.
Examples of the tertiary alkyl ester type acid dissociable, dissolution inhibiting group include an aliphatic branched acid dissociable, dissolution inhibiting group and an acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group.

Here, “aliphatic” in the claims and the specification is a relative concept with respect to aromatics, and is defined to mean groups, compounds, and the like that do not have aromaticity.
“Aliphatic branched” means having a branched structure having no aromaticity. The structure of the “aliphatic branched acid dissociable, dissolution inhibiting group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated.
As the aliphatic branched acid dissociable, dissolution inhibiting group, a tertiary alkyl group having 4 to 8 carbon atoms is preferable, and specific examples include a tert-butyl group, a tert-pentyl group, and a tert-heptyl group. .

The “aliphatic cyclic group” means a monocyclic group or a polycyclic group having no aromaticity.
The “aliphatic cyclic group” in the structural unit (a1) may or may not have a substituent. Examples of the substituent include a lower alkyl group having 1 to 5 carbon atoms, a fluorine atom, a fluorinated lower alkyl group having 1 to 5 carbon atoms substituted with a fluorine atom, an oxygen atom (= O), and the like.
The basic ring structure excluding the substituent of the “aliphatic cyclic group” is not limited to a group consisting of carbon and hydrogen (hydrocarbon group), but is preferably a hydrocarbon group. The “hydrocarbon group” may be either saturated or unsaturated, but is usually preferably saturated. The “aliphatic cyclic group” is preferably a polycyclic group.
Examples of the aliphatic cyclic group include monocycloalkanes, bicycloalkanes, tricycloalkanes, tetracycloalkanes that may or may not be substituted with a lower alkyl group, a fluorine atom or a fluorinated alkyl group. And groups obtained by removing one or more hydrogen atoms from a polycycloalkane. More specifically, 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 are exemplified. .

  Examples of the acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group include a group having a tertiary carbon atom on the ring skeleton of a cyclic alkyl group. Specifically, 2-methyl-2 -Adamantyl group, 2-ethyl-2-adamantyl group, etc. are mentioned. Alternatively, in the structural units represented by the following general formulas (a1 ″ -1) to (a1 ″ -6), an adamantyl group such as a group bonded to an oxygen atom of a carbonyloxy group (—C (O) —O—) An aliphatic cyclic group such as a cyclohexyl group, a cyclopentyl group, a norbornyl group, a tricyclodecanyl group, or a tetracyclododecanyl group, and a branched alkylene group having a tertiary carbon atom bonded thereto. Groups.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｒ^１５、Ｒ^１６はアルキル基（直鎖状、分岐鎖状のいずれでもよく、好ましくは炭素数１〜５である）を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; R ¹⁵ and R ^{16 each} represents an alkyl group (which may be linear or branched, and preferably has 1 to 5 carbon atoms. Is). ]

  In the general formulas (a1 ″ -1) to (a1 ″ -6), the lower alkyl group or halogenated lower alkyl group of R is a lower alkyl group or halogenated lower alkyl which may be bonded to the α-position of the acrylate ester. It is the same as the alkyl group.

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

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

[Wherein, R ¹ ′ and R ² ′ each independently represents a hydrogen atom or a lower alkyl group, n represents an integer of 0 to 3, and Y represents a lower alkyl group or an aliphatic cyclic group. ]

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

［式中、Ｒ^１’、ｎ、Ｙは上記と同様である。］

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

Examples of the lower alkyl group for Y include the same lower alkyl groups as those described above for R.
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 those in the formula group.

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

［式中、Ｒ^１７、Ｒ^１８はそれぞれ独立して直鎖状も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、分岐鎖状また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または分岐鎖状のアルキレン基であって、Ｒ^１７の末端とＲ^１９の末端とが結合して環を形成していてもよい。］

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

In R ¹⁷ and R ¹⁸ , the alkyl group preferably has 1 to 15 carbon atoms, may be linear or branched, and is preferably an ethyl group or a methyl group, and most preferably a methyl group. In particular, it is preferable that one of R ¹⁷ and R ¹⁸ is a hydrogen atom and the other is a methyl group.
R ¹⁹ is a linear, branched or cyclic alkyl group, preferably having 1 to 15 carbon atoms, and may be any of linear, branched or cyclic.
When R ¹⁹ is linear or branched, it preferably has 1 to 5 carbon atoms, more preferably an ethyl group or a methyl group, and most preferably an ethyl group.
When R ¹⁹ is cyclic, it preferably has 4 to 15 carbon atoms, more preferably 4 to 12 carbon atoms, and most preferably 5 to 10 carbon atoms. Specifically, one or more polycycloalkanes such as monocycloalkane, bicycloalkane, tricycloalkane, and tetracycloalkane, which may or may not be substituted with a fluorine atom or a fluorinated alkyl group, are included. Examples include a group excluding a hydrogen atom. Specific examples include monocycloalkanes such as cyclopentane and cyclohexane, and groups obtained by removing one or more hydrogen atoms from polycycloalkanes such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among them, a group obtained by removing one or more hydrogen atoms from adamantane is preferable.
In the above formula, R ¹⁷ and R ¹⁹ are each independently a linear or branched alkylene group (preferably an alkylene group having 1 to 5 carbon atoms), and the end of R ^{19 and} the end of 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.

  As the structural unit (a1), one or more selected from the group consisting of structural units represented by the following general formula (a1-0-1) and structural units represented by the following general formula (a1-0-2): Is preferably used.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｘ^１は酸解離性溶解抑制基を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; and X ¹ represents an acid dissociable, dissolution inhibiting group. ]

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し；Ｘ^２は酸解離性溶解抑制基を示し；Ｙ^２はアルキレン基または脂肪族環式基を示す。］

[Wherein, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group; X ² represents an acid dissociable, dissolution inhibiting group; Y ² represents an alkylene group or an aliphatic cyclic group. ]

In general formula (a1-0-1), the lower alkyl group or halogenated lower alkyl group for R is the same as the lower alkyl group or halogenated lower alkyl group that may be bonded to the α-position of the acrylate ester. .
X ¹ is not particularly limited as long as it is an acid dissociable, dissolution inhibiting group, and examples thereof include the above-described tertiary alkyl ester type acid dissociable, dissolution inhibiting group and acetal type acid dissociable, dissolution inhibiting group. And tertiary alkyl ester type acid dissociable, dissolution inhibiting groups are preferred.

In general formula (a1-0-2), R is the same as defined above.
X ² is the same as X ¹ in formula (a1-0-1).
Y ² is preferably an alkylene group having 1 to 4 carbon atoms or a divalent aliphatic cyclic group, and the aliphatic cyclic group is the above except that a group in which two or more hydrogen atoms are removed is used. The thing similar to description of an "aliphatic cyclic group" can be used.

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

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

[In the above formula, X ′ represents a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, Y represents a lower alkyl group having 1 to 5 carbon atoms, or an aliphatic cyclic group; Y ² represents an alkylene group or an aliphatic cyclic group; R is the same as defined above; R ¹ ′ and R ² ′ each independently represent a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms; Represents. ]

In the R ¹ ′ and R ² ′, at least one is preferably a hydrogen atom, and more preferably both are hydrogen atoms. n is preferably 0 or 1.

X ′ is the same as the tertiary alkyl ester type acid dissociable, dissolution inhibiting group exemplified in X ¹ above.
Examples of the aliphatic cyclic group for Y include the same groups as those exemplified above in the description of “aliphatic cyclic group”.
Y ² is preferably an alkylene group having 1 to 10 carbon atoms or a divalent aliphatic cyclic group, except that a group in which two or more hydrogen atoms are removed is used as the aliphatic cyclic group. The same as described for the “aliphatic cyclic group” can be used. When Y ² is an alkylene group having 1 to 10 carbon atoms, it is more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms, and most preferably 1 to 3 carbon atoms. . When Y ² is a divalent aliphatic cyclic group, a group in which two or more hydrogen atoms have been removed from cyclopentane, cyclohexane, norbornane, isobornane, adamantane, tricyclodecane, or tetracyclododecane is particularly preferable. .

  Specific examples of the structural units represented by the general formulas (a1-1) to (a1-4) are shown below.

Among the above, the structural unit represented by the general formula (a1-1) is preferable, and specifically, (a1-1-1) to (a1-1-6) and (a1-1-35) to (a1). It is more preferable to use at least one selected from the group -1-41).
Furthermore, as the structural unit (a1), in particular, those represented by the following general formula (a1-1-01) including the structural units of the formulas (a1-1-1) to (a1-1-4) The following general formula (a1-1-02) including the structural units of formulas (a1-1-35) to (a1-1-41) is also preferable.

（式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し、Ｒ^１１は低級アルキル基を示す。）

(In the formula, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, and R ¹¹ represents a lower alkyl group.)

（式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基を示し、Ｒ^１２は低級アルキル基を示す。ｈは１〜３の整数を表す）

(In the formula, R represents a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ¹² represents a lower alkyl group, and h represents an integer of 1 to 3)

In general formula (a1-1-01), R is the same as defined above.
The lower alkyl group for R ^{11 is the same as} the lower alkyl group for R, and is preferably a methyl group or an ethyl group.
In general formula (a1-1-02), R is the same as defined above.
The lower alkyl group for R ^{12 is the same as} the lower alkyl group for R, preferably a methyl group or an ethyl group, and most preferably an ethyl group. h is preferably 1 or 2, and most preferably 2.

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

・ Structural unit (a2)
The structural unit (a2) is a structural unit derived from an acrylate ester containing a lactone-containing cyclic group.
Here, the lactone-containing cyclic group refers to a cyclic group containing one ring (lactone ring) containing an —O—C (O) — structure. The lactone ring is counted as the first ring, and when it is only the lactone ring, it is called a monocyclic group, and when it has another ring structure, it is called a polycyclic group regardless of the structure.
When the component (A1) is used for forming a resist film, the lactone cyclic group of the structural unit (a2) increases the adhesion of the resist film to the substrate or has an affinity for a developer containing water. It is effective in raising.

As the structural unit (a2), any unit can be used without any particular limitation.
Specifically, examples of the lactone-containing monocyclic group include groups in which one hydrogen atom has been removed from γ-butyrolactone. Examples of the lactone-containing polycyclic group include groups in which one hydrogen atom has been removed from a bicycloalkane, tricycloalkane, or tetracycloalkane having a lactone ring.
More specifically, examples of the structural unit (a2) include structural units represented by general formulas (a2-1) to (a2-5) shown below.

［式中、Ｒは水素原子、低級アルキル基またはハロゲン化低級アルキル基であり、Ｒ’は水素原子、低級アルキル基、または炭素数１〜５のアルコキシ基であり、ｍは０または１の整数であり、Ａは炭素数１〜５のアルキレン基または酸素原子である。］

[Wherein, R is a hydrogen atom, a lower alkyl group or a halogenated lower alkyl group, R ′ is a hydrogen atom, a lower alkyl group, or an alkoxy group having 1 to 5 carbon atoms, and m is an integer of 0 or 1] And A is an alkylene group having 1 to 5 carbon atoms or an oxygen atom. ]

R in the general formulas (a2-1) to (a2-5) is the same as R in the structural unit (a1).
The lower alkyl group for R ′ is the same as the lower alkyl group for R in the structural unit (a1).
Specific examples of the alkylene group having 1 to 5 carbon atoms of A include a methylene group, an ethylene group, an n-propylene group, and an isopropylene group.
In general formulas (a2-1) to (a2-5), R ′ is preferably a hydrogen atom in view of industrial availability.
Below, the specific structural unit of the said general formula (a2-1)-(a2-5) is illustrated.

  As the structural unit (a2), at least one selected from the group consisting of structural units represented by the general formulas (a2-1) to (a2-5) is preferable, and the general formulas (a2-1) to ( At least one selected from the group consisting of structural units represented by a2-3) is more preferred. Among them, chemical formulas (a2-1-1), (a2-1-2), (a2-2-1), (a2-2-2), (a2-3-1), (a2-3-2) ), (A2-3-9) and (a2-3-10), at least one selected from the group consisting of structural units represented by (a2-3-10) is preferred.

As the structural unit (a2), one type may be used alone, or two or more types may be used in combination.
In the component (A1), the proportion of the structural unit (a2) is preferably 5 to 60 mol%, more preferably 10 to 50 mol%, based on the total of all the structural units constituting the component (A1). 50 mol% is more preferable. By making it the lower limit value or more, the effect of containing the structural unit (a2) can be sufficiently obtained, and by making it the upper limit value or less, it is possible to balance with other structural units.

・ Structural unit (a3)
The structural unit (a3) is a structural unit derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group.
When the component (A1) has the structural unit (a3), the hydrophilicity of the component (A1) is increased, the affinity with the developer is increased, the alkali solubility in the exposed area is improved, and the resolution is improved. Contributes to improvement.
Examples of the polar group include a hydroxyl group, a cyano group, a carboxy group, and a hydroxyalkyl group in which a part of hydrogen atoms of an alkyl group is substituted with a fluorine atom. A hydroxyl group is particularly preferable.
Examples of the aliphatic hydrocarbon group include a linear or branched hydrocarbon group having 1 to 10 carbon atoms (preferably an alkylene group) and a polycyclic aliphatic hydrocarbon group (polycyclic group). It is done. As the polycyclic group, for example, a resin for a resist composition for ArF excimer laser can be appropriately selected from among many proposed ones. The polycyclic group preferably has 7 to 30 carbon atoms.
Among them, a structural unit derived from an acrylate ester containing an aliphatic polycyclic group containing a hydroxyalkyl group in which a part of hydrogen atoms of a hydroxyl group, a cyano group, a carboxy group, or an alkyl group is substituted with a fluorine atom Is more preferable. Examples of the polycyclic group include groups in which two or more hydrogen atoms have been removed from bicycloalkane, tricycloalkane, tetracycloalkane and the like. Specific examples include groups in which two or more hydrogen atoms have been removed from a polycycloalkane such as adamantane, norbornane, isobornane, tricyclodecane, and tetracyclododecane. Among these polycyclic groups, there are groups in which two or more hydrogen atoms have been removed from adamantane, groups in which two or more hydrogen atoms have been removed from norbornane, and groups in which two or more hydrogen atoms have been removed from tetracyclododecane. Industrially preferable.

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

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

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

In formula (a3-1), j is preferably 1 or 2, and more preferably 1. When j is 2, it is preferable that the hydroxyl group is bonded to the 3rd and 5th positions of the adamantyl group. When j is 1, it is preferable that the hydroxyl group is bonded to the 3-position of the adamantyl group.
j is preferably 1, and a hydroxyl group bonded to the 3rd position of the adamantyl group is particularly preferred.
In formula (a3-2), k is preferably 1. The cyano group is preferably bonded to the 5th or 6th position of the norbornyl group.
In formula (a3-3), t ′ is preferably 1. l is preferably 1. s is preferably 1. These preferably have a 2-norbornyl group or a 3-norbornyl group bonded to the terminal of the carboxy group of acrylic acid. The fluorinated alkyl alcohol is preferably bonded to the 5th or 6th position of the norbornyl group.

As the structural unit (a3), one type may be used alone, or two or more types may be used in combination.
In the component (A1), the proportion of the structural unit (a3) is preferably 5 to 50 mol%, more preferably 5 to 40 mol%, and more preferably 5 to 25 mol% with respect to all the structural units constituting the component (A1). Is more preferable. By setting it to the lower limit value or more, the effect of containing the structural unit (a3) can be sufficiently obtained, and by setting it to the upper limit value or less, it is possible to balance with other structural units.

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

（式中、Ｒは前記と同じである。）

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

  When the structural unit (a4) is contained in the component (A1), the proportion of the structural unit (a4) in the component (A1) is 1 to 30 with respect to the total of all the structural units constituting the component (A1). Mol% is preferable and 10 to 20 mol% is more preferable.

In the present invention, the component (A1) preferably contains a copolymer having the structural units (a1), (a2) and (a3). Examples of the copolymer include copolymers composed of the structural units (a1), (a2) and (a3), copolymers composed of the structural units (a1), (a2), (a3) and (a4). Can be mentioned.
In the present invention, it is particularly preferable that the component (A) includes a copolymer having three types of structural units represented by the following formula (A1-11).

［式中、Ｒ、Ｒ^１１は上記と同様であり、複数のＲは相互に同じであっても異なっていてもよい。］

[Wherein, R and R ¹¹ are the same as above, and a plurality of R may be the same or different from each other. ]

Wherein ^{(A-11), R 11} is the same as ^{R 11} in the formula (a1-1-01) in, preferably a methyl group or an ethyl group, and most preferably an ethyl group.

The component (A1) can be obtained by polymerizing a monomer for deriving each structural unit by a known radical polymerization using a radical polymerization initiator such as azobisisobutyronitrile (AIBN).
Further, for the component (A1), in the polymerization, a chain transfer agent such as HS—CH ₂ —CH ₂ —CH ₂ —C (CF ₃ ) ₂ —OH is used in combination, so that the terminal A —C (CF ₃ ) ₂ —OH group may be introduced into the. As described above, a copolymer introduced with a hydroxyalkyl group in which a part of hydrogen atoms of the alkyl group is substituted with a fluorine atom reduces development defects and LER (line edge roughness: uneven unevenness of line side walls). It is effective in reducing

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

[(A2) component]
As the component (A2), a low molecular compound having a molecular weight of 500 or more and less than 2000 and having an acid dissociable, dissolution inhibiting group and a hydrophilic group as exemplified in the description of the component (A1) above is preferable. Specifically, a compound in which a part of hydrogen atoms of a hydroxyl group of a compound having a plurality of phenol skeletons is substituted with the acid dissociable, dissolution inhibiting group can be mentioned.
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 soluble dissolution inhibiting 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, 3, 4 nuclei of formalin condensates of phenols such as phenol, m-cresol, p-cresol or xylenol. Of course, it is not limited to these.
The acid dissociable, dissolution inhibiting group is not particularly limited, and examples thereof include those described above.

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

<(B) component>
The component (B) includes an acid generator component (B1) having no acid dissociable group-containing group (hereinafter referred to as (B1) component) and an acid generator component (B2) having an acid dissociable group-containing group. (Hereinafter referred to as the component (B2)).

[(B1) component]
The component (B1) is not particularly limited as long as it does not have an acid dissociable group, and what has been proposed as an acid generator for chemically amplified resists can be used. Examples of such acid generators include onium salt acid generators such as iodonium salts and sulfonium salts, oxime sulfonate acid generators, bisalkyl or bisarylsulfonyldiazomethanes, and poly (bissulfonyl) diazomethanes. There are various known diazomethane acid generators, nitrobenzyl sulfonate acid generators, imino sulfonate acid generators, disulfone acid generators, and the like.

  As the onium salt acid generator, for example, a compound represented by the following general formula (b-1) or (b-2) can be used.

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

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

In formula (b-1), R ¹ ″ to R ³ ″ each independently represents an aryl group or an alkyl group. In addition, any two of R ¹ ″ to R ³ ″ in formula (b-1) may be bonded to each other to form a ring together with the sulfur atom in the formula.
Further, at least one of R ¹ ″ to R ³ ″ represents an aryl group. Of R ¹ ″ to R ³ ″, two or more are preferably aryl groups, and most preferably all R ¹ ″ to R ³ ″ are aryl groups.
The aryl group for R ¹ ″ to R ³ ″ is not particularly limited, and is, for example, an aryl group having 6 to 20 carbon atoms, in which part or all of the hydrogen atoms are alkyl groups, alkoxy groups It may or may not be substituted with a group, a halogen atom, a hydroxyl group or the like. The aryl group is preferably an aryl group having 6 to 10 carbon atoms because it can be synthesized at a low cost. Specific examples include a phenyl group and a naphthyl group.
The alkyl group that may be substituted for the hydrogen atom of the aryl group is preferably an alkyl group having 1 to 5 carbon atoms, and is a methyl group, an ethyl group, a propyl group, an n-butyl group, or a tert-butyl group. Is most preferred.
As the alkoxy group in which the hydrogen atom of the aryl group may be substituted, 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, or an n-butoxy group. Most preferably it is.
The alkoxy group that may be substituted for the hydrogen atom of the aryl group is preferably an alkoxy group having 1 to 5 carbon atoms, and most preferably a methoxy group or an ethoxy group.
The halogen atom that may be substituted for the hydrogen atom of the aryl group is preferably a fluorine atom.
The alkyl group for R 1 ^{"~R 3",} is not particularly limited, for example, linear C1-10, branched or cyclic alkyl group, and the like. It is preferable that it is C1-C5 from the point which is excellent in resolution. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, an n-pentyl group, a cyclopentyl group, a hexyl group, a cyclohexyl group, a nonyl group, and a decanyl group. A methyl group is preferable because it is excellent in resolution and can be synthesized at low cost.
Among these, R ¹ ″ to R ³ ″ are most preferably a phenyl group or a naphthyl group, respectively.

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

R ⁴ ″ represents an alkyl group, a halogenated alkyl group, an aryl group, or an alkenyl group which may have a substituent.
The alkyl group for R ⁴ ″ may be linear, branched or cyclic.
The linear or branched alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 4 carbon atoms.
The cyclic alkyl group preferably has 4 to 15 carbon atoms, more preferably 4 to 10 carbon atoms, and most preferably 6 to 10 carbon atoms.

Examples of the halogenated alkyl group for R ⁴ ″ include groups in which part or all of the hydrogen atoms of the linear, branched, or cyclic alkyl group have been substituted with halogen atoms. A fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. are mentioned, A fluorine atom is preferable.
In the halogenated alkyl group, the ratio of the number of halogen atoms to the total number of halogen atoms and hydrogen atoms contained in the halogenated alkyl group (halogenation rate (%)) is preferably 10 to 100%. 50 to 100% is preferable, and 100% is most preferable. The higher the halogenation rate, the better the acid strength.

The aryl group for R ⁴ ″ is preferably an aryl group having 6 to 20 carbon atoms.
The alkenyl group in R ⁴ ″ is preferably an alkenyl group having 2 to 10 carbon atoms.

In the above R ⁴ ″, “optionally substituted” means one of hydrogen atoms in the linear, branched or cyclic alkyl group, halogenated alkyl group, aryl group, or alkenyl group. It means that part or all may be substituted with a substituent (an atom or group other than a hydrogen atom).
The number of substituents in R ⁴ ″ may be one or two or more.

Examples of the substituent include a halogen atom, a hetero atom, an alkyl group, R ¹ —O— [wherein R ¹ is a monovalent aromatic organic group, a monovalent aliphatic hydrocarbon group, or a hydroxyalkyl group. is there. ] Etc. which are represented by these.
Examples of the halogen atom and alkyl group include the same groups as those described above for R ⁴ ″ as the halogen atom and alkyl group in the halogenated alkyl group.
Examples of the hetero atom include an oxygen atom, a nitrogen atom, and a sulfur atom.

In the group represented by R ¹ —O—, the monovalent aromatic organic group represented by R ¹ includes a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, An aryl group such as a phenanthryl group obtained by removing one hydrogen atom from an aromatic hydrocarbon ring; a part of carbon atoms constituting the ring of the aryl group is a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom Substituted heteroaryl groups; arylalkyl groups such as benzyl group, phenethyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, 1-naphthylethyl group, 2-naphthylethyl group and the like.
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.
These aryl group, heteroaryl group, and arylalkyl group may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, an alkoxy group, a hydroxyl group, or a halogen atom. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group. Examples of the halogen atom include a fluorine atom, a chlorine atom, an iodine atom, and a bromine atom, and a fluorine atom is preferable.
The monovalent aromatic organic group for R ¹ is preferably an arylalkyl group, more preferably an arylmethyl group, and most preferably a naphthylmethyl group.

Examples of the monovalent aliphatic hydrocarbon group for R ¹ include a linear, branched or cyclic monovalent saturated hydrocarbon group having 1 to 15 carbon atoms, or a linear chain having 2 to 5 carbon atoms. Or branched monovalent aliphatic unsaturated hydrocarbon group.
Examples of the linear monovalent 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 decanyl group.
Examples of the branched monovalent saturated hydrocarbon group include 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 cyclic monovalent saturated hydrocarbon group may be either a polycyclic group or a monocyclic group, for example, one from a polycycloalkane such as a monocycloalkane, a bicycloalkane, a tricycloalkane, or a tetracycloalkane. And a group in which a hydrogen atom is removed. 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.
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.
The number of carbon atoms of the monovalent aliphatic hydrocarbon group R ¹ is 2 to 4 and most preferably 3.

The hydroxyalkyl group for R ¹ is a group in which at least one hydrogen atom of a linear, branched or cyclic monovalent saturated hydrocarbon group is substituted with a hydroxyl group. Those in which one or two hydrogen atoms of a linear or branched monovalent saturated hydrocarbon group are substituted with a hydroxyl group are preferred. Specific examples include a hydroxymethyl group, a hydroxyethyl group, a 1-hydroxypropyl group, a 2-hydroxypropyl group, a 3-hydroxypropyl group, and a 2,3-dihydroxypropyl group.
R The number of carbon atoms of the monovalent hydroxyalkyl group having ¹ preferably 1 to 10, more preferably 1 to 8, particularly preferably 1 to 6, 1 to 3 is most preferred.

In the present invention, R ⁴ ″ is preferably an alkyl group or a fluorinated alkyl group which may have a substituent, and the substituent is an alkyl group or a fluorinated group having the group represented by R ¹ —O—. An alkyl group is more preferred.

In the present invention, the anion moiety represented by R ⁴ ″ SO ₃ ^— in formula (b-1) or (b-2) is an anion moiety represented by the following general formula (b ″ -21). Most preferred.

［式中、Ｒ^１は１価の芳香族有機基、１価の脂肪族炭化水素基またはヒドロキシアルキル基であり；Ｙ^１は炭素数１〜４のアルキレン基またはフッ素化アルキレン基である。］

[Wherein, R ¹ represents a monovalent aromatic organic group, a monovalent aliphatic hydrocarbon group or a hydroxyalkyl group; Y ¹ represents an alkylene group having 1 to 4 carbon atoms or a fluorinated alkylene group. ]

In formula (b ″ -21), R ¹ is as described above.
Examples of the alkylene group having 1 to 4 carbon atoms or the fluorinated alkylene group represented by Y ¹ include —CF ₂ —, —CF ₂ CF ₂ —, —CF ₂ CF ₂ CF ₂ —, and —CF (CF ₃ ) CF ₂ —. _{, -CF (CF 2 CF 3)} -, - C (CF 3) 2 -, - CF 2 CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 CF 2 -, - CF 2 CF (CF 3 _{) CF 2 -, - CF (} CF 3) CF (CF 3) -, - C (CF 3) 2 CF 2 -, - CF (CF 2 CF 3) CF 2 -, - CF (CF 2 CF 2 CF 3 _{) -, - C (CF 3} ) (CF 2 CF 3) -; - CHF -, - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -, - CH (CF _{3) CH 2 -, - CH} (CF 2 CF 3) -, - C (CH 3) (CF 3 _{) -, - CH 2 CH 2} CH 2 CF 2 -, - CH 2 CH 2 CF 2 CF 2 -, - CH (CF 3) CH 2 CH 2 -, - CH 2 CH (CF 3) CH 2 -, - CH (CF ₃ ) CH (CF ₃ ) —, —C (CF ₃ ) ₂ CH ₂ —; —CH ₂ —, —CH ₂ CH ₂ —, —CH ₂ CH ₂ CH ₂ —, —CH (CH ₃ ) _{CH 2 -, - CH (CH} 2 CH 3) -, - C (CH 3) 2 -, - CH 2 CH 2 CH 2 CH 2 -, - CH (CH 3) CH 2 CH 2 -, - CH 2 CH _{(CH 3) CH 2 -,} - CH (CH 3) CH (CH 3) -, - C (CH 3) 2 CH 2 -, - CH (CH 2 CH 3) CH 2 -, - CH (CH 2 CH _{2 CH 3) -, - C} (CH 3) (CH 2 CH 3) -; and the like.

Y ¹ is preferably a fluorinated alkylene group having 1 to 4 carbon atoms, and particularly preferably a fluorinated alkylene group in which the carbon atom bonded to the adjacent sulfur atom is fluorinated. Examples of such fluorinated alkylene _{group, -CF 2 -, - CF 2} CF 2 -, - CF 2 CF 2 CF 2 -, - CF (CF 3) CF 2 -, - CF 2 CF 2 CF 2 CF 2 _{-, - CF (CF 3)} CF 2 CF 2 -, - CF 2 CF (CF 3) CF 2 -, - CF (CF 3) CF (CF 3) -, - C (CF 3) 2 CF 2 -, _{-CF (CF 2 CF 3) CF} 2 -; - CH 2 CF 2 -, - CH 2 CH 2 CF 2 -, - CH 2 CF 2 CF 2 -; - CH 2 CH 2 CH 2 CF 2 -, - CH ₂ CH ₂ CF ₂ CF ₂ —, —CH ₂ CF ₂ CF ₂ CF ₂ —; and the like.
Of _{these, -CF 2 CF 2 -, -} CF 2 CF 2 CF 2 -, or _CH 2 _CF 2 CF ₂ - is preferable, _-CF 2 CF ₂ - or _-CF 2 _CF 2 CF ₂ - is more preferable, -CF ₂ CF ₂ - is particularly preferred.

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

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

  In addition, in the general formula (b-1) or (b-2), an onium salt-based acid generator in which the anion moiety is replaced with an anion moiety represented by the following general formula (b-3) or (b-4). Can also be used (the cation moiety is the same as (b-1) or (b-2)).

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

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

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

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

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

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

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

The anion part of the sulfonium salt having a cation part represented by the formula (b-5) or (b-6) is not particularly limited, and is the same as the anion part of the onium salt acid generators proposed so far. It may be a thing. Examples of the anion moiety include fluorinated alkyl sulfonate ions such as the anion moiety (R ^{4 ″} SO ₃ ⁻ ) of the onium salt acid generator represented by the general formula (b-1) or (b-2). An anion moiety represented by the above general formula (b-3) or (b-4) and the like. Among these, an anion moiety represented by R ^{4 ″} SO ₃ ^— is preferable, and the general formula (b The anion moiety represented by “-21) is most preferable.

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

（式（Ｂ−１）中、Ｒ^３１、Ｒ^３２はそれぞれ独立に有機基を表す。）

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

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

As the organic group for R ^32, a linear, branched, or cyclic alkyl group, aryl group, or cyano group is preferable. As the alkyl group and aryl group for R ^32, the same alkyl groups and aryl groups as those described above for R ³¹ can be used.
R ³² is particularly preferably a cyano group, an alkyl group having 1 to 8 carbon atoms having no substituent, or a fluorinated alkyl group having 1 to 8 carbon atoms.

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

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

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

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

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

In the general formula (B-2), the alkyl group or halogenated alkyl group having no substituent of R ³³ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and carbon atoms. Numbers 1 to 6 are most preferable.
R ³³ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³³ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred.

As the aryl group of R ³⁴ , one hydrogen atom is removed from an aromatic hydrocarbon ring such as a phenyl group, a biphenyl group, a fluorenyl group, a naphthyl group, an anthryl group, or a phenanthryl group. And a heteroaryl group in which a part of carbon atoms constituting the ring of these groups is substituted with a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom. Among these, a fluorenyl group is preferable.
The aryl group of R ³⁴ may have a substituent such as an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, or an alkoxy group. The alkyl group or halogenated alkyl group in the substituent preferably has 1 to 8 carbon atoms, and more preferably 1 to 4 carbon atoms. The halogenated alkyl group is preferably a fluorinated alkyl group.

The alkyl group or halogenated alkyl group having no substituent of R ³⁵ preferably has 1 to 10 carbon atoms, more preferably 1 to 8 carbon atoms, and most preferably 1 to 6 carbon atoms.
R ³⁵ is preferably a halogenated alkyl group, more preferably a fluorinated alkyl group.
The fluorinated alkyl group for R ³⁵ is preferably such that the hydrogen atom of the alkyl group is 50% or more fluorinated, more preferably 70% or more fluorinated, and 90% or more fluorinated. Particularly preferred is the strength of the acid generated. Most preferably, it is a fully fluorinated alkyl group in which a hydrogen atom is 100% fluorine-substituted.

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

Specific examples of the oxime sulfonate acid generator include α- (p-toluenesulfonyloxyimino) -benzyl cyanide, α- (p-chlorobenzenesulfonyloxyimino) -benzyl cyanide, α- (4-nitrobenzenesulfonyloxy). Imino) -benzylcyanide, α- (4-nitro-2-trifluoromethylbenzenesulfonyloxyimino) -benzylcyanide, α- (benzenesulfonyloxyimino) -4-chlorobenzylcyanide, α- (benzenesulfonyl) Oxyimino) -2,4-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -2,6-dichlorobenzyl cyanide, α- (benzenesulfonyloxyimino) -4-methoxybenzyl cyanide, α- ( 2-Chlorobenzenesulfonyloxyimino) 4-methoxybenzylcyanide, α- (benzenesulfonyloxyimino) -thien-2-ylacetonitrile, α- (4-dodecylbenzenesulfonyloxyimino) -benzylcyanide, α-[(p-toluenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α-[(dodecylbenzenesulfonyloxyimino) -4-methoxyphenyl] acetonitrile, α- (tosyloxyimino) -4-thienyl cyanide, α- (methylsulfonyloxyimino) -1-cyclo Pentenyl acetonitrile, α- (methylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -1-cycloheptenylacetonitrile, α- (methylsulfonyloxyimino) -1-cyclooctene Acetonitrile, α- (trifluoromethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -cyclohexylacetonitrile, α- (ethylsulfonyloxyimino) -ethylacetonitrile, α- (propyl Sulfonyloxyimino) -propylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclopentylacetonitrile, α- (cyclohexylsulfonyloxyimino) -cyclohexylacetonitrile, α- (cyclohexylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- ( Ethylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclope N-tenyl acetonitrile, α- (n-butylsulfonyloxyimino) -1-cyclopentenylacetonitrile, α- (ethylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (isopropylsulfonyloxyimino) -1-cyclohexenylacetonitrile , Α- (n-butylsulfonyloxyimino) -1-cyclohexenylacetonitrile, α- (methylsulfonyloxyimino) -phenylacetonitrile, α- (methylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (trifluoro Methylsulfonyloxyimino) -phenylacetonitrile, α- (trifluoromethylsulfonyloxyimino) -p-methoxyphenylacetonitrile, α- (ethylsulfonyloxyimino) -p- Butoxy phenylacetonitrile, alpha-(propylsulfonyl oxyimino)-p-methylphenyl acetonitrile, alpha-like (methylsulfonyloxyimino)-p-bromophenyl acetonitrile.
Further, an oxime sulfonate-based acid generator disclosed in JP-A-9-208554 (paragraphs [0012] to [0014] [chemical formula 18] to [chemical formula 19]), WO2004 / 074242A2 (pages 65 to 85). The oxime sulfonate acid generators disclosed in Examples 1 to 40) of No. 1 can also be suitably used.
Moreover, the following can be illustrated as a suitable thing.

  Of the above exemplified compounds, the following four compounds are preferred.

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

(B1) As a component, these acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.
As the component (B1), an onium salt-based acid generator having an anion portion represented by R ^{4 ″} SO ₃ ^— is preferable, and among them, the anion portion represented by the general formula (b ″ -21) is preferably selected. What has is most preferable.
In the component (B), the ratio of the component (B1) is preferably 1 to 15% by mass, more preferably 1 to 10% by mass, and further preferably 2 to 8% by mass with respect to the total mass of the component (B). When the proportion of the component (B1) is within the above range, the effect of the present invention is improved.

[(B2) component]
The component (B2) is not particularly limited as long as it has an acid dissociable group, and examples thereof include those in which an acid dissociable group-containing group is introduced into the acid generator mentioned as the component (B1). . Here, the acid-dissociable group-containing group is a group containing an acid-dissociable group in the structure thereof, and may be an acid-dissociable group itself. (A group or atom that remains bonded to the acid generator even after the acid dissociable group is dissociated).
As the acid dissociable group, for example, those proposed so far as the acid dissociable, dissolution inhibiting group of the base resin for chemically amplified resist can be used. Specific examples thereof include the same acid dissociable, dissolution inhibiting groups exemplified in the structural unit (a1). However, the acid dissociable group in the component (B2) needs to have an alkali dissolution inhibiting property that makes the entire component (A1) hardly soluble in an alkali developer before dissociation, such as an acid dissociable dissolution inhibiting group. Absent.
Examples of the group composed of an acid dissociable group and a group or atom that does not dissociate with an acid include, for example, —O—Z ¹ , —CO—O—Z ² [wherein Z ¹ and Z ² are acid groups, respectively. It is a dissociable group. ] Etc. are mentioned.
The method for introducing a group containing an acid dissociable group into the acid generator is not particularly limited, and a known method can be used. For example, among the components (B1), an acid generator having a hydrophilic group such as a hydroxyl group or a carboxy group is prepared, and the hydrogen atom of the hydrophilic group is substituted with an acid-dissociable group-containing group.

  In the present invention, the acid dissociable group-containing group of the component (B2) is preferably a group represented by the following general formula (I-1) or (I-2).

［式中、Ｒ^５０は直鎖状もしくは分岐鎖状のアルキレン基であり、Ｒ^５１は酸解離性基である。Ｒ^５７およびＲ^５８は、それぞれ独立に、水素原子またはアルキル基であり、Ｒ^５９はアルキル基であり、Ｒ^５８の末端とＲ^５９の末端とが相互に結合して環を形成していてもよい。］

[Wherein, R ⁵⁰ represents a linear or branched alkylene group, and R ⁵¹ represents an acid dissociable group. R ⁵⁷ and R ⁵⁸ are each independently a hydrogen atom or an alkyl group, R ⁵⁹ is an alkyl group, and the end of R ^{58 and} the end of R ⁵⁹ may be bonded to each other to form a ring. Good. ]

In formula (I-1), the linear or branched alkylene group represented by R ⁵⁰ preferably has 1 to 5 carbon atoms, such as a methylene group, an ethylene group, a trimethylene group, or a tetramethylene group. 1,1-dimethylethylene group and the like.
The acid dissociable group in R ⁵¹ is not particularly limited as long as it is an organic group that can be dissociated by the action of an acid, and examples thereof include cyclic or chain tertiary alkyl ester type acid dissociable groups; Examples thereof include the same acid dissociable, dissolution inhibiting groups as mentioned in the structural unit (a1), such as an acetal type acid dissociable group. Among these, tertiary alkyl ester type acid dissociable groups are preferable. Specifically, 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, etc. Is mentioned.

In formula (I-2), R ⁵⁷ and R ⁵⁸ are each independently a hydrogen atom or a linear or branched alkyl group, provided that at least one of R ⁵⁷ and R ⁵⁸ is a hydrogen atom. is there.
In R ⁵⁷ and R ⁵⁸ , the alkyl group preferably has 1 to 5 carbon atoms, preferably an ethyl group or a methyl group, and most preferably a methyl group.
One of R ⁵⁷ and R ⁵⁸ is preferably a hydrogen atom, the other is preferably a hydrogen atom or a methyl group, and both R ⁵⁷ and R ⁵⁸ are particularly preferably hydrogen atoms.
The alkyl group of R ^59, preferably from 1 to 15 carbon atoms, linear, branched, may be any of circular.
The linear or branched alkyl group for R ⁵⁹ 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 ⁵⁹ 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.
R ⁵⁸ and R ⁵⁹ may be bonded to each other to form one ring structure. In this case, a cyclic group is formed by R ⁵⁸ , R ⁵⁹ , the oxygen atom to which R ⁵⁹ is bonded, and the carbon atom to which the oxygen atom and R ⁵⁸ are bonded. The cyclic group is preferably a 4- to 7-membered ring, and more preferably a 4- to 6-membered ring.

  In this invention, since (B2) component is excellent in the effect of this invention, it is preferable to contain the onium salt type | system | group acid generator which has a cation part which has an acid dissociable group. Especially, it is preferable that this onium salt type | system | group acid generator has a cation part represented by the following general formula (b "-11) or (b" -12). By having such a cation moiety, the effect of the present invention is improved. Further, a resist pattern, particularly a contact hole resist pattern can be formed in a better shape. This is presumably because the solubility of the component (B2) in the resist solvent is improved by having the cation moiety.

［式中、Ｒ^４７”〜Ｒ^４９”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またはアルキル基であり、Ｒ^４７”〜Ｒ^４９”のうちの少なくとも１つは、下記一般式（Ｉ）で表される置換基を有するアリール基であり、Ｒ^４７”〜Ｒ^４９”のうちのいずれか２つが相互に結合して式中の硫黄原子と共に環を形成してもよい。］

[Wherein, R ⁴⁷ ″ to R ⁴⁹ ″ each independently represents an aryl group or an alkyl group which may have a substituent, and at least one of R ⁴⁷ ″ to R ⁴⁹ ″ is the following: It is an aryl group having a substituent represented by the general formula (I), and any two of R ⁴⁷ ″ to R ⁴⁹ ″ may be bonded to each other to form a ring together with the sulfur atom in the formula . ]

［式中、Ｒ^４０”は酸解離性基含有基である。］

[Wherein R ⁴⁰ ″ is an acid-dissociable group-containing group.]

［式中、Ｒ^４０”は酸解離性基含有基であり、Ｒ^４１”〜Ｒ^４３”は、それぞれ独立に、アルキル基、アセチル基、アルコキシ基、カルボキシ基、水酸基またはヒドロキシアルキル基であり、ｎ_４０は１〜３の整数であり、ｎ_４１〜ｎ_４３は、それぞれ独立に、０〜３の整数であり、ｎ_４０＋ｎ_４１は５以下である。］

[Wherein R ⁴⁰ ″ is an acid-dissociable group-containing group, and R ⁴¹ ″ to R ⁴³ ″ are each independently an alkyl group, an acetyl group, an alkoxy group, a carboxy group, a hydroxyl group, or a hydroxyalkyl group, n ₄₀ is an integer of 1 to 3, n _{41 to} n ₄₃ are each independently an integer of 0 to 3, and n ₄₀ + n ₄₁ is 5 or less.]

In formula (b ″ -11), at least one of R ⁴⁷ ″ to R ⁴⁹ ″ is an aryl group having a substituent represented by the general formula (I).
The aryl group having a substituent represented by the general formula (I) ^is preferably ^R 47 "~R ^49" 1 or is two ^of, among ^R 47 "~R ^49" It is preferable that it is one of these.
Examples of the acid dissociable group-containing group for R ⁴⁰ ″ include the same groups as the acid dissociable group-containing groups listed above, and are particularly represented by general formula (I-1) or (I-2). Groups are preferred.

When one or two of R ⁴⁷ ″ to R ⁴⁹ ″ are an aryl group having a substituent represented by the general formula (I), the remaining groups may each independently have a substituent. A good aryl or alkyl group. Examples of the aryl group or alkyl group include those similar to the aryl group or alkyl group represented by R ¹ ″ to R ³ ″ in the general formula (b-1) described in the component (B1).
In R ⁴⁷ ″ to R ⁴⁹ ″, groups other than the aryl group having a substituent represented by the general formula (I) each have a substituent other than the substituent represented by the general formula (I). It is preferably a phenyl group or a naphthyl group which may be present, and more preferably a phenyl group which may have a substituent other than the substituent represented by the general formula (I).
As a substituent other than the substituent represented by the general formula (I), an alkyl group having 1 to 5 carbon atoms is preferable, and a methyl group is most preferable.

When one of R ⁴⁷ ″ to R ⁴⁹ ″ is an aryl group having a substituent represented by the general formula (I), the remaining two are bonded to each other to form a ring together with a sulfur atom in the formula May be formed. In this case, it is preferable to form a 3- to 10-membered ring including a sulfur atom, and it is particularly preferable to form a 5- to 7-membered ring.

In the formula (b ″ -12), examples of the acid dissociable group-containing group for R ⁴⁰ ″ include the same groups as the acid dissociable group-containing groups listed above, and in particular, the general formula (I-1) or The group represented by (I-2) is preferable.
Alkyl group ^{R 41} "~R ^43", an acetyl group, an alkoxy group, the carboxyl group, hydroxyl group or hydroxyalkyl group, wherein (B1) mentioned in component, ^R 41 to R in general formula (b-5) The thing similar to ⁴⁶ is mentioned.
n ₄₀ is an integer of 1 to 3, preferably 1 or 2, and most preferably 1.
n ₄₁ is an integer of 0 to 3, preferably 0 to 2, more preferably 0 or 1, and still more preferably 0.
n ₄₀ + n ₄₁ is 5 or less.
n ₄₂ and n ₄₃ are each independently an integer of 0 to 3, preferably 0 or 1, and more preferably 0.

  Preferred specific examples of the cation moiety represented by the formula (b ″ -11) or (b ″ -12) include the following general formulas (b ″ -11-1), (b ″ -11-2), (b The cation part etc. which are represented by "-12-1) or (b" -12-4) are mentioned.

［式中、Ｚ’はそれぞれ独立に第３級アルキルエステル型酸解離性溶解抑制基であり、Ｚ”はそれぞれ独立にアルキル基であり、Ｒ^８、Ｒ^９はそれぞれ独立に低級アルキル基であり、ｎ_８、ｎ_９はそれぞれ独立に０〜２の整数である。］

[Wherein Z ′ is independently a tertiary alkyl ester type acid dissociable, dissolution inhibiting group, Z ″ is independently an alkyl group, and R ⁸ and R ⁹ are each independently a lower alkyl group. , N ₈ and n ₉ are each independently an integer of 0 to 2.]

Examples of Z ′ include the same tertiary alkyl ester-type acid dissociable, dissolution inhibiting groups as those described above for the structural unit (a1). The tertiary alkyl ester type acid dissociable, dissolution inhibiting group is preferably an acid dissociable, dissolution inhibiting group containing an aliphatic cyclic group, and a group having a tertiary carbon atom on the ring skeleton of a cyclic alkyl group. Is more preferable. In particular, 2-alkyl-2-adamantyl groups such as 2-methyl-2-adamantyl group and 2-ethyl-2-adamantyl group are preferable.
Examples of Z ″ include the same groups as those exemplified as the alkyl group for R ^{59 in} the general formula (I-2), and a cyclic alkyl group is particularly preferable.
R ⁸ and R ⁹ are each independently preferably an alkyl group having 1 to 5 carbon atoms, and most preferably a methyl group.
When n ₈ or n ₉ is 2, two R ⁸ or R ⁹ may be the same or different from each other.
The bonding position of R ⁸ or R ⁹ is not particularly limited. For example, when n ₈ or n ₉ is 1, the 2-position of the phenyl group is preferable. When n ₈ or n ₉ is 2, the 3rd and 5th positions are preferred.

When an onium salt acid generator having a cation moiety having an acid-dissociable group, such as the general formulas (b ″ -11) and (b ″ -12), is used as the component (B2), the component (B2) The anion moiety is not particularly limited, and may be the same as the anion moiety of the onium salt acid generators proposed so far. As such an anion moiety, for example, the anion moiety (R ^{4 ″} SO ₃ ⁻ ) of the onium salt acid generator represented by the general formula (b-1) or (b-2) mentioned in the component (B1) above. Fluorinated alkyl sulfonate ions such as: an anion moiety represented by the general formula (b-3) or (b-4), etc. Among these, an anion moiety represented by R ^{4 ″} SO ₃ ^— The anion moiety represented by the general formula (b ″ -21) is most preferable.

(B2) As a component, these acid generators may be used individually by 1 type, and may be used in combination of 2 or more type.
In the component (B), the ratio of the component (B2) is preferably 1 to 15% by mass, more preferably 1 to 10% by mass, and further preferably 2 to 8% by mass with respect to the total mass of the component (B). When the proportion of the component (B1) is within the above range, the effect of the present invention is improved.

In the component (B), the content ratio (molar ratio) of the component (B1) and the component (B2) is excellent in the effects of the present invention, so the component (B1): component (B2) = 9: 1 to 1 : 9 is preferable, 8: 2 to 2: 8 is more preferable, and 7: 3 to 3: 7 is more preferable.
Moreover, in (B) component, since it is excellent in the effect of this invention, (B1) component and / or (B2) component have an anion part represented by the said general formula (b ''-21). preferable.
0.5-30 mass parts is preferable with respect to 100 mass parts of (A) component, and, as for content of (B) component in the resist composition of this invention, 1-20 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>
In the resist composition of the present invention, a nitrogen-containing organic compound (D) (hereinafter, referred to as “component (D)”) is further blended as an optional component in order to improve the resist pattern shape, stability with time, and the like. Can be made.
Since a wide variety of components (D) have already been proposed, any known one may be used. Among them, aliphatic amines, particularly secondary aliphatic amines and tertiary aliphatic amines are used. preferable. Here, the aliphatic amine is an amine having one or more aliphatic groups, and the aliphatic groups preferably have 1 to 12 carbon atoms.
Examples of the aliphatic amine include an amine (alkyl amine or alkyl alcohol amine) or a cyclic amine in which at least one hydrogen atom of ammonia NH ₃ is substituted with an alkyl group or hydroxyalkyl group having 12 or less carbon atoms.
Specific examples of alkylamines and alkyl alcohol amines include monoalkylamines such as n-hexylamine, n-heptylamine, n-octylamine, n-nonylamine, n-decylamine; diethylamine, di-n-propylamine, di- -Dialkylamines such as n-heptylamine, di-n-octylamine, dicyclohexylamine; trimethylamine, triethylamine, tri-n-propylamine, tri-n-butylamine, tri-n-hexylamine, tri-n-pentylamine , Tri-n-heptylamine, tri-n-octylamine, tri-n-nonylamine, tri-n-decanylamine, tri-n-dodecylamine, etc .; diethanolamine, triethanolamine, diisopropanolamine Triisopropanolamine, di -n- octanol amines, alkyl alcohol amines tri -n- octanol amine. Among these, a C5-C10 trialkylamine is preferable and a tri-n-pentylamine is the most preferable.
Examples of the cyclic amine include heterocyclic compounds containing a nitrogen atom as a hetero atom. The heterocyclic compound may be monocyclic (aliphatic monocyclic amine) or polycyclic (aliphatic polycyclic amine).
Specific examples of the aliphatic monocyclic amine include piperidine and piperazine.
As the aliphatic polycyclic amine, those having 6 to 10 carbon atoms are preferable. Specifically, 1,5-diazabicyclo [4.3.0] -5-nonene, 1,8-diazabicyclo [5. 4.0] -7-undecene, hexamethylenetetramine, 1,4-diazabicyclo [2.2.2] octane, and the like.
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.

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

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

≪Resist pattern formation method≫
The resist pattern forming method of the present invention includes a step of forming a resist film on a support using the resist composition, a step of exposing the resist film, and a step of developing the resist film to form a resist pattern. Including.
The resist pattern forming method of the present invention can be performed, for example, as follows.
That is, 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, at a temperature of 80 to 150 ° C. Then, after selectively exposing ArF excimer laser light through a desired mask pattern, for example, with an ArF exposure apparatus or the like, PEB (post-exposure heating) is performed for 40 to 120 seconds under a temperature condition of 80 to 150 ° C. Preferably, it is applied for 60 to 90 seconds. Subsequently, this is developed using an alkali developer, for example, an aqueous solution of 0.1 to 10% by mass of tetramethylammonium hydroxide (TMAH), preferably rinsed with pure water and dried. In some cases, a baking process (post-bake) may be performed after the development process. In this way, a resist pattern faithful to the mask pattern can be obtained.

The support is not particularly limited, and a conventionally known one can be used, and examples thereof include a substrate for electronic components and a substrate on which a predetermined wiring pattern is formed. More specifically, a silicon substrate, a metal substrate such as copper, chromium, iron, and aluminum, a glass substrate, and the like can be given. As a material for the wiring pattern, for example, copper, aluminum, nickel, gold or the like can be used.
Further, the support may be a substrate in which an inorganic and / or organic film is provided on the above-described substrate. An inorganic antireflection film (inorganic BARC) is an example of the inorganic film. Examples of the organic film include an organic antireflection film (organic BARC).

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

The exposure 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, as described above, the portion between the lens, which has been conventionally filled with an inert gas such as air or nitrogen, and the resist film on the wafer at the time of exposure is refracted larger than the refractive index of air. The exposure is performed in a state filled with a solvent having a high rate (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.).

According to the resist composition and resist pattern forming method of the present invention, excellent MEF can be achieved.
As described above, MEF is a parameter indicating how faithfully a mask pattern having a different line width or aperture can be reproduced with the same exposure amount, and the closer the MEF is to 1, the better the mask reproducibility is. It shows that.
In the MEF, for example, a plurality of patterns having different target sizes (pattern widths to be formed, such as line width in a line-and-space pattern and hole diameter in a contact hole pattern) are provided at the same pitch 2. Using the above masks, resist patterns can be formed with the same exposure amount, and the mask size can be obtained as the slope of a straight line when plotted on the horizontal axis and the size of the formed resist pattern on the vertical axis.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.
(Examples 1-3, Comparative Examples 1-2)
<Preparation of resist composition>
Each component shown in Table 1 was mixed and dissolved to prepare a positive resist composition.

In Table 1, each abbreviation indicates the following, and the numerical value in [] is the blending amount (part by mass).
(A) -1: Mw = 7000, Mw / Mn = 2.0 represented by the following structural formula (A) -1 (wherein 1 / m / n = 40/40/20 (molar ratio)) Copolymer.
(B) -1: a compound represented by the following formula (B) -1.
(B) -2: A compound represented by the following formula (B) -2.
(D) -1: tri-n-pentylamine.
(S) -1: PGMEA / PGME = 6: 4 mixed solvent

  In addition, the compounding quantity of (B) component in Examples 1-3 and Comparative Examples 1-2 is equimolar amount. In addition, the blending ratio of the component (B) in Examples 1 to 3 (ratio (molar ratio) of blending amounts of (B) -1 and (B) -2) is (B) -1: (B ) -2 = 75: 25, 50:50, 25:75.

<Evaluation of lithography properties>
The lithography properties of the obtained resist composition were evaluated by the following procedure.
[Resolution and sensitivity]
An organic antireflection film composition “ARC29” (trade name, manufactured by Brewer Science Co., Ltd.) is applied onto an 8-inch silicon wafer using a spinner, and baked on a hot plate at 205 ° C. for 60 seconds to be dried. Thereby, an organic antireflection film having a film thickness of 89 nm was formed. Then, the resist composition obtained above is applied onto the antireflection film using a spinner, prebaked (PAB) on a hot plate at 90 ° C. for 60 seconds, and dried. Thus, a resist film having a thickness of 120 nm was formed.
Next, a protective film-forming coating solution “TSRC-002” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) is applied onto the resist film using a spinner and heated at 90 ° C. for 60 seconds. A top coat having a thickness of 29 nm was formed.
Next, an immersion ArF exposure apparatus NSR-S609B (manufactured by Nikon; NA (numerical aperture) = 1.07, 2/3 annular illumination, reduction magnification 1 / with respect to the resist film on which the top coat is formed. The ArF excimer laser (193 nm) was selectively irradiated through a mask pattern of a hole pattern in which holes with a hole diameter of 75 nm were arranged at equal intervals (pitch of 131 nm) by 4 times, immersion medium: water.
Next, the top coat is removed using a protective film removing solution “TS-Remover-S” (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.), and then subjected to PEB treatment at 95 ° C. for 60 seconds, and further to 23 ° C. Then, it was developed with a 2.38 mass% TMAH aqueous solution NMD-W (trade name, manufactured by Tokyo Ohka Kogyo Co., Ltd.) for 60 seconds, then rinsed with pure water for 30 seconds, and then shaken and dried.
As a result, in each example, a resist pattern of a hole pattern in which holes with a hole diameter of 70 nm are arranged at equal intervals (pitch of 131 nm) was formed on the resist film.
At this time, the optimum exposure dose Eop (mJ / cm ² ) at which a hole pattern with a diameter of 70 nm and a pitch of 131 nm was formed was determined. The results are shown in Table 2.

[Mask error factor (MEF) evaluation]
In the Eop, hole patterns having a pitch of 131 nm were formed using mask patterns having mask sizes of 75 nm, 77 nn, and 79 nm, respectively. At this time, the slope of a straight line when the mask size was plotted on the horizontal axis and the diameter of holes formed in the resist film using each mask pattern was plotted on the vertical axis was calculated as MEF. MEF (1) showed the rate (%) in which Examples 1 to 3 were improved based on the value of Comparative Example 1. MEF (2) showed the rate (%) in which Examples 1 to 3 were improved based on the value of Comparative Example 2. The results are shown in Table 2.

  As is clear from the above results, the resist compositions of Examples 1 to 3 in which (B) -1 and (B) -2 are used in combination use (B) -1 or (B) -2 alone. Compared to any of Comparative Examples 1 and 2, the MEF was good.

Claims (7)

A resist composition containing a base material component (A) whose solubility in an alkaline developer 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) whose solubility in an alkaline developer is increased by the action of an acid, and the resin component (A1) contains an acid dissociable, dissolution inhibiting group. And a structural unit (a2) derived from an acrylate ester containing a lactone-containing cyclic group,
The acid generator component (B) contains an acid generator component (B1) having no acid dissociable group-containing group and an acid generator component (B2) having an acid dissociable group-containing group ,
The resist composition, wherein the acid dissociable group-containing group is a group represented by the following general formula (I-1) or (I-2) .

[Wherein, R ⁵⁰ represents a linear or branched alkylene group, and R ⁵¹ represents an acid dissociable group. R ⁵⁷ and R ⁵⁸ are each independently a hydrogen atom or an alkyl group, R ⁵⁹ is an alkyl group, and the end of R ^{58 and} the end of R ⁵⁹ may be bonded to each other to form a ring. Good. ] A resist composition containing a base material component (A) whose solubility in an alkaline developer 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) whose solubility in an alkaline developer is increased by the action of an acid, and the resin component (A1) contains an acid dissociable, dissolution inhibiting group. A structural unit derived from (a1), and a structural unit derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group (a3),
The acid generator component (B) contains an acid generator component (B1) having no acid dissociable group-containing group and an acid generator component (B2) having an acid dissociable group-containing group ,
The resist composition, wherein the acid dissociable group-containing group is a group represented by the following general formula (I-1) or (I-2) .

[Wherein, R ⁵⁰ represents a linear or branched alkylene group, and R ⁵¹ represents an acid dissociable group. R ⁵⁷ and R ⁵⁸ are each independently a hydrogen atom or an alkyl group, R ⁵⁹ is an alkyl group, and the end of R ^{58 and} the end of R ⁵⁹ may be bonded to each other to form a ring. Good. ]   The resist composition according to claim 1, wherein the resin component (A1) further has a structural unit (a3) derived from an acrylate ester containing a polar group-containing aliphatic hydrocarbon group. The resist composition according to claim 1, wherein the acid generator component (B2) has a cation moiety represented by the following general formula (b ″ -11) or (b ″ -12). .

[Wherein, R ⁴⁷ ″ to R ⁴⁹ ″ each independently represents an aryl group or an alkyl group which may have a substituent, and at least one of R ⁴⁷ ″ to R ⁴⁹ ″ is the following: It is an aryl group having a substituent represented by the general formula (I), and any two of R ⁴⁷ ″ to R ⁴⁹ ″ may be bonded to each other to form a ring together with the sulfur atom in the formula . ]

^{Wherein, R 40} "is the acid-dissociable group-containing group.]

[ Wherein , R ⁴⁰ ″ is the acid-dissociable group-containing group, and R ⁴¹ ″ to R ⁴³ ″ are each independently an alkyl group, an acetyl group, an alkoxy group, a carboxy group, a hydroxyl group, or a hydroxyalkyl group. N ₄₀ is an integer of 1 to 3, n _{41 to} n ₄₃ are each independently an integer of 0 to 3, and n ₄₀ + n ₄₁ is 5 or less.] The acid generator component (B1) and / or (B2) is, the resist composition according to any one of claim 1 to 4 having an anion moiety represented by the following general formula (b "-21).

[Wherein, R ¹ represents a monovalent aromatic organic group, a monovalent aliphatic hydrocarbon group or a hydroxyalkyl group; Y ¹ represents an alkylene group having 1 to 4 carbon atoms or a fluorinated alkylene group. ] The resist composition as described in any one of Claims 1-5 containing a nitrogen-containing organic compound (D). A step of forming a resist film on a support using the resist composition according to any one of claims 1 to 6 , a step of exposing the resist film, and an alkali development of the resist film to form a resist pattern A resist pattern forming method including a forming step.