JP7115822B2 - RESIST COMPOSITION AND RESIST PATTERN MANUFACTURING METHOD - Google Patents

Description

The present invention relates to a resist composition and a method for producing a resist pattern.

特許文献２には、下記式で表される塩を含有するレジスト組成物が記載されている。

特許文献３には、下記式で表される塩を含有するレジスト組成物が記載されている。

特許文献４には、下記式で表される塩を酸発生剤として含有するレジスト組成物が記載されている。

Patent Document 1 describes a resist composition containing a salt represented by the following formula.

Patent Document 2 describes a resist composition containing a salt represented by the following formula.

Patent Document 3 describes a resist composition containing a salt represented by the following formula.

Patent Document 4 describes a resist composition containing a salt represented by the following formula as an acid generator.

JP 2006-257078 A Japanese Unexamined Patent Application Publication No. 2007-224008 JP 2013-41257 A JP 2012-97074 A

Conventional resist compositions have not been able to suppress fluctuations in the focus margin (DOF) of the resulting resist pattern as the resist composition ages. Moreover, even if the variation could be suppressed, the focus margin of the obtained resist pattern was not satisfactory.

［式（ａ１－０）、式（ａ１－１）及び式（ａ１－２）中、
Ｌ^a01、Ｌ^ａ１及びＬ^ａ２は、それぞれ独立に、－Ｏ－又は^＊－Ｏ－（ＣＨ_２）_ｋ１－ＣＯ－Ｏ－を表し、ｋ１は１～７のいずれかの整数を表し、＊は－ＣＯ－との結合手を表す。
Ｒ^a01、Ｒ^ａ４及びＲ^ａ５は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ^a02、Ｒ^a03及びＲ^a04は、それぞれ独立に、炭素数１～８のアルキル基、炭素数３～１８の脂環式炭化水素基又はこれらを組み合わせた基を表す。
Ｒ^ａ６及びＲ^ａ７は、それぞれ独立に、炭素数１～８のアルキル基、炭素数３～１８の脂環式炭化水素基又はこれらを組合せることにより形成される基を表す。
ｍ１は０～１４のいずれかの整数を表す。
ｎ１は０～１０のいずれかの整数を表す。
ｎ１’は０～３のいずれかの整数を表す。］
〔４〕樹脂が、さらに、ラクトン環を有し、かつ酸不安定基を有さない構造単位を含む〔１〕～〔３〕のいずれか記載のレジスト組成物。
〔５〕ラクトン環を有し、かつ酸不安定基を有さない構造単位が、式（ａ３－４）で表される構造単位である〔４〕記載のレジスト組成物。

［式（ａ３－４）中、
Ｒ^ａ２４は、ハロゲン原子を有してもよい炭素数１～６のアルキル基、水素原子又はハロゲン原子を表す。
Ｌ^ａ７は、－Ｏ－、^＊－Ｏ－Ｌ^ａ８－Ｏ－、^＊－Ｏ－Ｌ^ａ８－ＣＯ－Ｏ－、^＊－Ｏ－Ｌ^ａ８－ＣＯ－Ｏ－Ｌ^ａ９－ＣＯ－Ｏ－又は^＊－Ｏ－Ｌ^ａ８－Ｏ－ＣＯ－Ｌ^ａ９－Ｏ－を表す。
＊は－ＣＯ－との結合手を表す。
Ｌ^ａ８及びＬ^ａ９は、互いに独立に、炭素数１～６のアルカンジイル基を表す。
Ｒ^ａ２５は、カルボキシ基、シアノ基又は炭素数１～４の脂肪族炭化水素基を表す。
ｗ１は、０～８のいずれかの整数を表す。ｗ１が２以上のとき、複数のＲ^ａ２５は互いに同一であってもよく、異なってもよい。］
〔６〕樹脂が、さらに、ヒドロキシ基を有する構造単位を含む〔１〕～〔５〕のいずれか記載のレジスト組成物。
〔７〕酸発生剤から発生する酸が、環の構成要素として－Ｏ－ＳＯ－Ｏ－を含む環構造を有する〔１〕～〔６〕のいずれか記載のレジスト組成物。
〔８〕溶剤が、γ－ブチロラクトンを含む〔１〕～〔７〕のいずれか記載のレジスト組成物。
〔９〕γ－ブチロラクトンの溶剤中に占める割合が、０．１％重量％以上５重量％以下である〔８〕記載のレジスト組成物。
〔１０〕γ－ブチロラクトンの溶剤中に占める割合が、０．２％重量％以上３重量％以下である〔９〕記載のレジスト組成物。
〔１１〕γ－ブチロラクトンの溶剤中に占める割合が、０．３％重量％以上１．５重量％以下である〔８〕記載のレジスト組成物。
〔１２〕さらに、溶剤が、プロピレングリコールモノメチルエーテルアセテート、プロピレングリコールモノメチルエーテル及びケトン系溶剤の中から選ばれる少なくとも１種を含む〔８〕～〔１１〕のいずれか記載のレジスト組成物。
〔１３〕ケトン系溶剤が、２－ヘプタノンである〔１２〕記載のレジスト組成物。
〔１４〕さらに、フッ素原子を有する構造単位を含む樹脂を含有する〔１〕～〔１３〕のいずれか記載のレジスト組成物。
〔１５〕酸発生剤から発生する酸よりも酸性度の弱い酸を発生する塩をさらに含有する〔１〕～〔１４〕のいずれか記載のレジスト組成物。
〔１６〕（１）〔１〕～〔１５〕のいずれかに記載のレジスト組成物を基板上に塗布する工程、
（２）塗布後の組成物を乾燥させて組成物層を形成する工程、
（３）組成物層に露光する工程、
（４）露光後の組成物層を加熱する工程、及び
（５）加熱後の組成物層を現像する工程を含むレジストパターンの製造方法。 The present invention includes the following inventions.
[1] A resist composition containing a resin containing a structural unit having an acid-labile group, an acid generator and a solvent,
The acid generator is an acid generator that generates an acid having a hydrogen bond term (δh) of 12 (MPa) ^1/2 or more and 15 (MPa) ^1/2 or less in the Hansen solubility parameters, and
A resist composition that is an acid generator that generates an acid having a solubility index (R) of 7.50 or less based on the Hansen solubility parameter for γ-butyrolactone, represented by the following formula (1).
R=(4(δd−18.0) ² +(δp−16.6) ² +(δh−7.4) ² ) ^1/2 (1)
(In formula (1),
δd represents the dispersion term in the Hansen solubility parameter,
δp denotes the polar term in the Hansen solubility parameters,
δh denotes the hydrogen bonding term in the Hansen solubility parameters. )
[2] The resist composition according to [1], wherein the acid generator generates an acid having a molar volume of 850 cm ³ /mol or more.
[3] The structural unit having an acid labile group is at least one selected from the group consisting of structural units represented by formula (a1-0), formula (a1-1) and formula (a1-2). The resist composition according to [1] or [2].

[In formula (a1-0), formula (a1-1) and formula (a1-2),
L ^a01 , L ^a1 and L ^a2 each independently represent —O— or ^* —O—(CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, * is represents a bond with -CO-.
R ^a01 , R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a02 , R ^a03 and R ^a04 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group formed by combining these.
m1 represents any integer from 0 to 14;
n1 represents any integer from 0 to 10;
n1' represents an integer of 0 to 3; ]
[4] The resist composition according to any one of [1] to [3], wherein the resin further contains a structural unit having a lactone ring and no acid-labile group.
[5] The resist composition of [4], wherein the structural unit having a lactone ring and no acid labile group is a structural unit represented by formula (a3-4).

[In formula (a3-4),
R ^a24 represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
L ^a7 is -O-, ^* -OL ^a8 -O-, ^* -OL ^a8 -CO-O-, ^* -OL ^a8 -CO- ^{OL a9} -CO-O- or ^* -OL ^a8 -O-CO-L ^a9 -O-.
* represents a bond with -CO-.
L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms.
R ^a25 represents a carboxy group, a cyano group or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
w1 represents any integer from 0 to 8; When w1 is 2 or more, a plurality of R ^a25 may be the same or different. ]
[6] The resist composition according to any one of [1] to [5], wherein the resin further contains a structural unit having a hydroxy group.
[7] The resist composition according to any one of [1] to [6], wherein the acid generated from the acid generator has a ring structure containing --O--SO--O-- as a ring constituent.
[8] The resist composition according to any one of [1] to [7], wherein the solvent contains γ-butyrolactone.
[9] The resist composition of [8], wherein the proportion of γ-butyrolactone in the solvent is 0.1% by weight or more and 5% by weight or less.
[10] The resist composition of [9], wherein the proportion of γ-butyrolactone in the solvent is 0.2% by weight or more and 3% by weight or less.
[11] The resist composition of [8], wherein the proportion of γ-butyrolactone in the solvent is 0.3% by weight or more and 1.5% by weight or less.
[12] The resist composition according to any one of [8] to [11], wherein the solvent further contains at least one selected from propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether and ketone solvents.
[13] The resist composition of [12], wherein the ketone solvent is 2-heptanone.
[14] The resist composition according to any one of [1] to [13], further comprising a resin containing a structural unit having a fluorine atom.
[15] The resist composition according to any one of [1] to [14], further comprising a salt that generates an acid weaker in acidity than the acid generated from the acid generator.
[16] (1) a step of applying the resist composition according to any one of [1] to [15] onto a substrate;
(2) a step of drying the applied composition to form a composition layer;
(3) exposing the composition layer;
(4) A process of heating the composition layer after exposure, and (5) a process of developing the composition layer after heating.

According to the resist composition of the present invention, it is possible to obtain a resist pattern which has a good DOF and whose change over time is suppressed.

In this specification, the term "(meth)acrylic monomer" refers to a monomer having "CH ₂ =CH-CO-" and a monomer having "CH ₂ =C(CH ₃ )-CO-" in the molecule. means at least one Similarly, "(meth)acrylate" and "(meth)acrylic acid" mean "at least one of acrylate and methacrylate" and "at least one of acrylic acid and methacrylic acid", respectively.

[Resist composition]
The resist composition of the present invention is
A resin containing a structural unit having an acid-labile group (hereinafter sometimes referred to as "resin (A)"), an acid generator (hereinafter sometimes referred to as "acid generator (I)") and a solvent (hereinafter sometimes referred to as " (sometimes referred to as "solvent (E)").
Here, the term "acid-labile group" refers to a structure having a leaving group, and the leaving group is eliminated by contact with an acid, and the constitutional unit has a hydrophilic group (for example, a hydroxy group or a carboxy group). means a group that converts into units.
The resist composition of the present invention further comprises a resin other than resin (A) (hereinafter sometimes referred to as resin (X)), an acid generator other than acid generator (I), and a quencher (hereinafter, "quencher"). It may contain one or more selected from the group consisting of solvents (sometimes referred to as "char (C)"), and preferably contains a quencher (C).

<Hansen Solubility Parameter>
Hansen solubility parameters can be used as an example for specifying an acid generator having desired properties in the resist composition of the present invention.

The Hansen solubility parameter is obtained by dividing the solubility of a substance into three components (dispersion term δd, polar term δp, hydrogen bonding term δh) and expressing them in three-dimensional space. The dispersion term δd indicates the effect of the dispersion force, the polar term δp indicates the effect of the dipole force, and the hydrogen bond term δh indicates the effect of the hydrogen bond force.
The definition and calculation of the Hansen Solubility Parameter is given in Charles M. et al. Hansen, Hansen Solubility Parameters: A Users Handbook (CRC Press, 2007). Moreover, by using computer software Hansen Solubility Parameters in Practice (HSPiP), the Hansen Solubility Parameters can be easily estimated from the chemical structure of compounds for which literature values are not known. For the acid generator (I) in the present invention, the dispersion term δd, the polarity term δp, and the hydrogen bond term δh were determined using HSPiP version 4.1 and estimated values.

In general, the Hansen solubility parameter of an acid generated by a particular acid generator is determined by a solubility test in which a sample of the acid generated by the acid generator is dissolved in a number of different solvents with established Hansen solubility parameters and the solubility is measured. can decide. Specifically, among the solvents used in the solubility test, all the three-dimensional points of the solvent in which the acid generated from the acid generator is dissolved are included inside the sphere, and the points of the undissolved solvent are outside the sphere. A sphere (solubility sphere) is searched for and the central coordinates of the sphere are defined as the Hansen solubility parameter of the acid generated from the acid generator.
For example, when the Hansen solubility parameters of another solvent that is not used for measuring the Hansen solubility parameters of the acid generated from the acid generator is (δd, δp, δh), the point indicated by the coordinates is the above It is considered that the solvent dissolves the acid generator if it is included inside the solubility sphere of the acid generated from the acid generator. On the other hand, if the coordinate point is outside the solubility sphere of the acid generator, it is considered that the solvent cannot dissolve the acid generated from the acid generator.

In the present invention, for γ-butyrolactone, it is assumed that an acid at a certain distance from coordinates (18, 16.6, 7.4), which is the Hansen solubility parameter, is moderately soluble in γ-butyrolactone. It is preferable to use an acid generator (I) that generates an acid such as
For example, γ-butyrolactone has a Hansen solubility parameter dispersion term of 18.0 (MPa) ^1/2 , a polar term of 16.6 (MPa) ^1/2 and a hydrogen bonding term of 7.4 (MPa) ^1/2 . , the solubility parameter distance R from γ-butyrolactone represented by formula (1) based on the Hansen solubility parameter is sometimes referred to as the solubility index (hereinafter, solubility index (R)) for the acid generated from the acid generator (I). Yes.)
R=(4(δd−18.0) ² +(δp−16.6) ² +(δh−7.4) ² ) ^1/2 (1)
(In formula (1),
δd represents the dispersion term in the Hansen solubility parameter,
δp denotes the polar term in the Hansen solubility parameters,
δh denotes the hydrogen bonding term in the Hansen solubility parameters. )

The acid generator (I) in the present invention uses the Hansen solubility parameter coordinates (δd, δp, δh), and the hydrogen bond term (δh) of the acid generated from the acid generator (I) is 12 (MPa). ^1/2 or more and 15 (MPa) ^1/2 , preferably 12.5 (MPa) ^1/2 or more and 15.0 (MPa) ^1/2 or less, 13.0 (MPa) ^1/2 or more It is more preferably 15.0 (MPa) ^1/2 or less. Also, the polarity term (δp) is preferably 19 or less, more preferably 18.5 or less.
Further, based on the Hansen solubility parameter, the solubility index (R) of the acid generated from the acid generator (I) with respect to γ-butyrolactone is 7.50 or less, preferably 7.30 or less. It is more preferably 0.10 or less.
Furthermore, the molar volume of the acid generated from the acid generator (I) (calculated by Chem Draw Ultra Ver11.0 Clinical Vol.) is preferably 850 cm ³ /mol or more, more preferably 900 cm ³ /mol or more. It is preferably 3000 cm ³ /mol or less, more preferably 2000 cm ³ /mol or more. The molar volume of the acid generator (I) is determined according to Chem Draw Ultra Ver11.0 Clinical Vol. Calculated by
More preferably, the acid generator (I) simultaneously satisfies the above-mentioned hydrogen bond term, solubility index (R) and molar volume of the acid.

<Resin (A)>
Resin (A) is a resin containing a structural unit having an acid-labile group (hereinafter sometimes referred to as "structural unit (a1)"), and is decomposed by the action of acid, resulting in decreased solubility in butyl acetate. It is preferable to have the characteristic
The resin (A) preferably further contains structural units other than the structural unit (a1). Structural units other than the structural unit (a1) include a structural unit having no acid-labile group (hereinafter sometimes referred to as "structural unit (s)"), other structural units (hereinafter referred to as "structural unit (t)"). sometimes called).

［式（１）中、Ｒ^ａ１～Ｒ^ａ３は、それぞれ独立に、炭素数１～８のアルキル基、炭素数３～２０の脂環式炭化水素基又はこれらを組合せた基を表すか、Ｒ^ａ１及びＲ^ａ２は互いに結合してそれらが結合する炭素原子とともに炭素数３～２０の２価の脂環式炭化水素基を形成する。
ｎａは、０又は１を表す。
＊は結合手を表す。］

［式（２）中、Ｒ^ａ１’及びＲ^ａ２’は、それぞれ独立に、水素原子又は炭素数１～１２の炭化水素基を表し、Ｒ^ａ３’は、炭素数１～２０の炭化水素基を表すか、Ｒ^ａ２’及びＲ^ａ３’は互いに結合してそれらが結合する炭素原子及びＸとともに炭素数３～２０の２価の複素環基を形成し、該炭化水素基及び該２価の複素環基に含まれる－ＣＨ_２－は、－Ｏ－又は－Ｓ－で置き換わってもよい。
Ｘは、酸素原子又は硫黄原子を表す。
＊は結合手を表す。］ <Structural unit (a1)>
The structural unit (a1) is derived from a monomer having an acid-labile group (hereinafter sometimes referred to as "monomer (a1)").
The acid-labile group contained in the resin (A) is preferably a group represented by formula (1) and/or a group represented by formula (2).

[In formula (1), R ^a1 to R ^a3 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a group combining these; ^a1 and R ^a2 are bonded to each other to form a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atoms to which they are bonded.
na represents 0 or 1;
* represents a bond. ]

[In formula (2), R ^a1′ and R ^a2′ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, and R ^a3′ represents a hydrocarbon group having 1 to 20 carbon atoms. or R ^a2′ and R ^a3′ are bonded to each other to form a divalent heterocyclic group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded and X, and the hydrocarbon group and the divalent heterocyclic —CH ₂ — included in the ring group may be replaced with —O— or —S—.
X represents an oxygen atom or a sulfur atom.
* represents a bond. ]

アルキル基と脂環式炭化水素基とを組合せた基としては、例えば、メチルシクロヘキシル基、ジメチルシクロへキシル基、メチルノルボルニル基、シクロヘキシルメチル基、アダマンチルメチル基、ノルボルニルエチル基等が挙げられる。
ｎａは、好ましくは０である。 Examples of alkyl groups of R ^a1 to R ^a3 include methyl group, ethyl group, propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group and n-octyl group.
The alicyclic hydrocarbon groups of R ^a1 to R ^a3 may be either monocyclic or polycyclic. Examples of monocyclic alicyclic hydrocarbon groups include cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. Examples of polycyclic alicyclic hydrocarbon groups include decahydronaphthyl group, adamantyl group, norbornyl group, and the following groups (* represents a bond). The alicyclic hydrocarbon groups of R ^a1 to R ^a3 are preferably alicyclic hydrocarbon groups having 3 to 16 carbon atoms.

Examples of groups in which an alkyl group and an alicyclic hydrocarbon group are combined include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, a norbornylethyl group, and the like. mentioned.
na is preferably zero.

Examples of —C(R ^a1 )(R ^a2 )(R ^a3 ) when R ^a1 and R ^a2 combine to form a divalent alicyclic hydrocarbon group include the following groups. The divalent alicyclic hydrocarbon group preferably has 3-12 carbon atoms. * represents a bond with -O-.

Examples of groups represented by formula (1) include 1,1-dialkylalkoxycarbonyl groups (groups in which R ^a1 to R ^a3 in formula (1) are alkyl groups, preferably tert-butoxycarbonyl groups). , 2-alkyladamantan-2-yloxycarbonyl group (in formula (1), R ^a1 , R ^a2 and the carbon atom to which they are bonded form an adamantyl group, and R ^a3 is an alkyl group) and 1- (Adamantan-1-yl)-1-alkylalkoxycarbonyl group (in formula (1), R ^a1 and R ^a2 are alkyl groups and R ^a3 is an adamantyl group), and the like.

Ｒ^ａ１’及びＲ^ａ２’のうち、少なくとも１つは水素原子であることが好ましい。 The hydrocarbon groups of R ^a1′ to R ^a3′ include alkyl groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups and groups formed by combining these.
Examples of the alkyl group and the alicyclic hydrocarbon group are the same as those described above.
Aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, p-methylphenyl, p-tert-butylphenyl, p-adamantylphenyl, tolyl, xylyl, cumenyl, mesityl and biphenyl groups. group, phenanthryl group, 2,6-diethylphenyl group, aryl group such as 2-methyl-6-ethylphenyl group, and the like.
The divalent heterocyclic group formed by R ^a2′ and R ^a3′ bonding to each other to form the carbon atom to which they are bonded and X includes the following groups. * represents a bond.

At least one of R ^a1′ and R ^a2′ is preferably a hydrogen atom.

Specific examples of the group represented by formula (2) include the following groups. * represents a bond.

Monomer (a1) is preferably a monomer having an acid labile group and an ethylenically unsaturated bond, more preferably a (meth)acrylic monomer having an acid labile group.

Among (meth)acrylic monomers having an acid-labile group, those having an alicyclic hydrocarbon group having 5 to 20 carbon atoms are preferred. When the resin (A) having a structural unit derived from the monomer (a1) having a bulky structure such as an alicyclic hydrocarbon group is used in the resist composition, the resolution of the resist pattern can be improved.

［式（ａ１－０）、式（ａ１－１）及び式（ａ１－２）中、
Ｌ^a01、Ｌ^ａ１及びＬ^ａ２は、それぞれ独立に、－Ｏ－又は^＊－Ｏ－（ＣＨ_２）_ｋ１－ＣＯ－Ｏ－を表し、ｋ１は１～７のいずれかの整数を表し、＊は－ＣＯ－との結合手を表す。
Ｒ^a01、Ｒ^ａ４及びＲ^ａ５は、それぞれ独立に、水素原子又はメチル基を表す。
Ｒ^a02、Ｒ^a03及びＲ^a04は、それぞれ独立に、炭素数１～８のアルキル基、炭素数３～１８の脂環式炭化水素基又はこれらを組み合わせた基を表す。
Ｒ^ａ６及びＲ^ａ７は、それぞれ独立に、炭素数１～８のアルキル基、炭素数３～１８の脂環式炭化水素基又はこれらを組合せることにより形成される基を表す。
ｍ１は０～１４のいずれかの整数を表す。
ｎ１は０～１０のいずれかの整数を表す。
ｎ１’は０～３のいずれかの整数を表す。］ As a structural unit derived from a (meth)acrylic monomer having a group represented by formula (1), preferably a structural unit represented by formula (a1-0), represented by formula (a1-1) structural units or structural units represented by formula (a1-2). These may be used alone or in combination of two or more. In this specification, a structural unit represented by formula (a1-0), a structural unit represented by formula (a1-1), and a structural unit represented by formula (a1-2) are each referred to as structural unit (a1 -0), structural unit (a1-1) and structural unit (a1-2).

[In formula (a1-0), formula (a1-1) and formula (a1-2),
L ^a01 , L ^a1 and L ^a2 each independently represent —O— or ^* —O—(CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, * is represents a bond with -CO-.
R ^a01 , R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a02 , R ^a03 and R ^a04 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group formed by combining these.
m1 represents any integer from 0 to 14;
n1 represents an integer from 0 to 10;
n1' represents an integer of 0 to 3; ]

L ^a01 , L ^a1 and L ^a2 are preferably an oxygen atom or ^* —O—(CH ₂ ) _k01 —CO—O— (provided that k01 is preferably any integer of 1 to 4, more preferably is 1.), more preferably an oxygen atom.
R ^a4 and R ^a5 are preferably methyl groups.
As R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 , alkyl groups, alicyclic hydrocarbon groups and groups in which these are combined are the same groups as those listed for R ^a1 to R ^a3 in formula (1). groups.
The alkyl groups of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 preferably have 1 to 6 carbon atoms, more preferably methyl or ethyl.
The alicyclic hydrocarbon groups of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 preferably have 3 to 8 carbon atoms, more preferably 3 to 6 carbon atoms.
The combined group of an alkyl group and an alicyclic hydrocarbon group preferably has a total carbon number of 4 to 18 in combination with the alkyl group and the alicyclic hydrocarbon group. Examples of such groups include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a methyladamantyl group, a cyclohexylmethyl group, a methylcyclohexylmethyl group, an adamantylmethyl group and a norbornylmethyl group. be done.
R ^a04 is preferably an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 5 to 12 carbon atoms, more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group.
m1 is preferably an integer from 0 to 3, more preferably 0 or 1.
n1 is preferably an integer from 0 to 3, more preferably 0 or 1.
n1' is preferably 0 or 1.

As the structural unit (a1-0), for example, a structural unit represented by any one of formulas (a1-0-1) to (a1-0-12) and R ^a01 in formula (a1-0) Structural units in which the corresponding methyl group is replaced with a hydrogen atom can be mentioned, and structural units represented by any one of formulas (a1-0-1) to (a1-0-10) are preferred.

モノマー（ａ１－１）としては、例えば、特開２０１０－２０４６４６号公報に記載されたモノマーが挙げられる。中でも、式（ａ１－１－１）～式（ａ１－１－４）のいずれかで表されるモノマーが好ましい。

Examples of the monomer (a1-1) include monomers described in JP-A-2010-204646. Among them, monomers represented by any one of formulas (a1-1-1) to (a1-1-4) are preferred.

Examples of structural units (a1-1) include structural units derived from monomers described in JP-A-2010-204646. Among them, structural units represented by any one of formulas (a1-1-1) to (a1-1-4) are preferred.

上記の構造単位において、式（ａ１－１）及び式（ａ１－２）中のＲ^ａ４、Ｒ^ａ５に相当するメチル基が水素原子に置き換わったモノマーも、上記モノマーの具体例として挙げられる。 The structural unit (a1-2) is preferably a structural unit represented by any one of formulas (a1-2-1) to (a1-2-6), more preferably a structural unit represented by formula (a1-2 -2) and structural units represented by formula (a1-2-5) are preferred.

Specific examples of the above monomers include monomers in which the methyl groups corresponding to R ^a4 and R ^a5 in formulas (a1-1) and (a1-2) in the above structural units are replaced with hydrogen atoms.

When the resin (A) contains the structural unit (a1-0) and/or the structural unit (a1-1) and/or the structural unit (a1-2), the total content of these is the total structure of the resin (A) It is generally 10 to 95 mol %, preferably 15 to 90 mol %, more preferably 20 to 85 mol %, relative to the total number of units.

樹脂（Ａ）が上記構造単位を含む場合、その含有率は、樹脂（Ａ）の全構造単位に対して、１０～９５モル％が好ましく、１５～９０モル％がより好ましく、２０～８５モル％がさらに好ましい。 Furthermore, structural units (a1) having a group represented by formula (1) include structural units represented by the following structural unit formulas (a1-3-1) to (a1-3-7). .

When the resin (A) contains the above structural unit, its content is preferably 10 to 95 mol%, more preferably 15 to 90 mol%, and 20 to 85 mol, based on the total structural units of the resin (A). % is more preferred.

［式（ａ１－４）中、
Ｒ^a32は、水素原子、ハロゲン原子、又は、ハロゲン原子を有してもよい炭素数１～６のアルキル基を表す。
Ｒ^a33は、ハロゲン原子、ヒドロキシ基、炭素数１～６のアルキル基、炭素数１～６のアルコキシ基、炭素数２～４のアルキルカルボニル基、炭素数２～４のアルキルカルボニルオキシ基、アクリロイルオキシ基又はメタクリロイルオキシ基を表す。
ｌａは０～４のいずれかの整数を表す。ｌａが２以上である場合、複数のＲ^a33は互いに同一であっても異なってもよい。
Ｒ^a34及びＲ^a35はそれぞれ独立に、水素原子又は炭素数１～１２の炭化水素基を表し、Ｒ^a36は、炭素数１～２０の炭化水素基を表すか、Ｒ^a35及びＲ^a36は互いに結合してそれらが結合する－Ｃ－Ｏ－とともに炭素数２～２０の２価の炭化水素基を形成し、該炭化水素基及び該２価の炭化水素基に含まれる－ＣＨ₂－は、－Ｏ－又は－Ｓ－で置き換わってもよい。］ Further, the structural unit (a1) having group (2) (hereinafter sometimes referred to as "structural unit (a1-4)") includes the following structural units.

[In formula (a1-4),
R ^a32 represents a hydrogen atom, a halogen atom, or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
R ^a33 is a halogen atom, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 4 carbon atoms, an alkylcarbonyloxy group having 2 to 4 carbon atoms, acryloyl It represents an oxy group or a methacryloyloxy group.
la represents an integer of 0 to 4; When la is 2 or more, a plurality of R ^a33 may be the same or different.
R ^a34 and R ^a35 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, R ^a36 represents a hydrocarbon group having 1 to 20 carbon atoms, or R ^a35 and R ^a36 are bonded to each other to form a C2-C20 divalent hydrocarbon group together with -C-O- to which they are bonded, and -CH ₂ - contained in the hydrocarbon group and the divalent hydrocarbon group is - O- or -S- may be substituted. ]

樹脂（Ａ）が上記構造単位を含む場合、その含有率は、樹脂（Ａ）の全構造単位に対して、１０～９５モル％が好ましく、１５～９０モル％がより好ましく、２０～８５モル％がさらに好ましく、２５～６５モル％が一層好ましい。 Examples of structural units (a1-4) include structural units derived from monomers described in JP-A-2010-204646. Preferably, structural units represented by formulas (a1-4-1) to (a1-4-8) and structures in which the hydrogen atom corresponding to R ^a32 in formula (a1-4) is replaced with a methyl group units, more preferably structural units represented by formulas (a1-4-1) to (a1-4-5).

When the resin (A) contains the above structural unit, its content is preferably 10 to 95 mol%, more preferably 15 to 90 mol%, and 20 to 85 mol, based on the total structural units of the resin (A). %, more preferably 25 to 65 mol %.

［式（ａ１－５）中、
Ｒ^ａ８は、ハロゲン原子を有してもよい炭素数１～６のアルキル基、水素原子又はハロゲン原子を表す。
Ｚ^ａ１は、単結合又は＊－（ＣＨ_２）_ｈ３－ＣＯ－Ｌ^５４－を表し、ｈ３は１～４のいずれかの整数を表し、＊は、Ｌ^５１との結合手を表す。
Ｌ^５１、Ｌ^５２、Ｌ^５３及びＬ^５４は、それぞれ独立に、－Ｏ－又は－Ｓ－を表す。
ｓ１は、１～３のいずれかの整数を表す。
ｓ１’は、０～３のいずれかの整数を表す。］ As the structural unit derived from a (meth)acrylic monomer having a group represented by formula (2), a structural unit represented by formula (a1-5) (hereinafter referred to as "structural unit (a1-5)" There is) is also mentioned.

[In formula (a1-5),
R ^a8 represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
Z ^a1 represents a single bond or *—(CH ₂ ) _h3 —CO—L ⁵⁴ —, h3 represents an integer of 1 to 4, and * represents a bond with L ⁵¹ .
L ⁵¹ , L ⁵² , L ⁵³ and L ⁵⁴ each independently represent -O- or -S-.
s1 represents an integer of 1 to 3;
s1' represents any integer from 0 to 3; ]

A halogen atom includes a fluorine atom and a chlorine atom, preferably a fluorine atom. Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, fluoromethyl group and trifluoromethyl. groups.
In formula (a1-5), R ^a8 is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.
L ⁵¹ is preferably an oxygen atom.
Preferably, one of L ⁵² and L ⁵³ is —O— and the other is —S—.
s1 is preferably one.
s1′ is preferably an integer of 0-2.
Z ^a1 is preferably a single bond or *—CH ₂ —CO—O—.

Examples of the monomer leading to the structural unit (a1-5) include monomers described in JP-A-2010-61117. Among them, monomers represented by formulas (a1-5-1) to (a1-5-4) are preferable, and monomers represented by formula (a1-5-1) or formula (a1-5-2) is more preferred.

When the resin (A) has the structural unit (a1-5), the content thereof is preferably 1 to 50 mol%, preferably 3 to 45 mol%, based on the total of all structural units of the resin (A). It is more preferably mol %, and even more preferably 5 to 40 mol %.

The structural unit (a1) having an acid labile group in the resin (A) includes structural unit (a1-0), structural unit (a1-1), structural unit (a1-2) and structural unit (a1-5 ) is preferably at least one selected from the group consisting of, more preferably at least two or more, a combination of the structural unit (a1-1) and the structural unit (a1-2), the structural unit (a1-2) and the structural unit ( a1-0), combination of structural unit (a1-1) and structural unit (a1-0), combination of structural unit (a1-0), structural unit (a1-1) and structural unit (a1-2) is more preferable, a combination of structural unit (a1-1) and structural unit (a1-0), a combination of structural unit (a1-2) and structural unit (a1-0), structural unit (a1-0), structural unit A combination of (a1-1) and structural unit (a1-2) is particularly preferred.
Structural unit (a1) preferably includes structural unit (a1-2).

<Structural unit (s)>
Structural unit (s) is derived from a monomer having no acid-labile group (hereinafter sometimes referred to as "monomer (s)"). As the monomer (s), a monomer having no acid-labile group known in the field of resists can be used.
The structural unit (s) preferably has a hydroxy group or a lactone ring. A structural unit having a hydroxy group and no acid-labile group (hereinafter sometimes referred to as "structural unit (a2)") and/or a structure having a lactone ring and no acid-labile group When a resin having a unit (hereinafter sometimes referred to as "structural unit (a3)") is used in the resist composition of the present invention, the resolution of the resist pattern and adhesion to the substrate can be improved.

<Structural unit (a2)>
The hydroxy group possessed by the structural unit (a2) may be an alcoholic hydroxy group or a phenolic hydroxy group.
When producing a resist pattern from the resist composition of the present invention, when using a high-energy beam such as a KrF excimer laser (248 nm), an electron beam, or EUV (extreme ultraviolet light) as the exposure light source, the structural unit (a2) , it is preferable to use a structural unit (a2) having a phenolic hydroxy group. Further, when using an ArF excimer laser (193 nm) or the like, the structural unit (a2) having an alcoholic hydroxy group is preferable as the structural unit (a2). As the structural unit (a2), one type may be contained alone, or two or more types may be contained.

When the resin (A) has a structural unit (a2-0) having a phenolic hydroxy group, its content should be 5 to 95 mol% of the total of all structural units of the resin (A). is preferred, 10 to 80 mol % is more preferred, 15 to 80 mol % is even more preferred, and 35 to 65 mol % is even more preferred.

［式（ａ２－１）中、
Ｌ^ａ３は、－Ｏ－又は^＊－Ｏ－（ＣＨ_２）_ｋ２－ＣＯ－Ｏ－を表し、
ｋ２は１～７のいずれかの整数を表す。＊は－ＣＯ－との結合手を表す。
Ｒ^ａ１４は、水素原子又はメチル基を表す。
Ｒ^ａ１５及びＲ^ａ１６は、それぞれ独立に、水素原子、メチル基又はヒドロキシ基を表す。
ｏ１は、０～１０のいずれかの整数を表す。］ The structural unit (a2) having an alcoholic hydroxy group includes a structural unit represented by formula (a2-1) (hereinafter sometimes referred to as "structural unit (a2-1)").

[In the formula (a2-1),
L ^a3 represents -O- or ^* -O-(CH ₂ ) _k2 -CO-O-,
k2 represents any integer from 1 to 7; * represents a bond with -CO-.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 each independently represent a hydrogen atom, a methyl group or a hydroxy group.
o1 represents any integer from 0 to 10; ]

In formula (a2-1), L ^a3 is preferably —O—, —O—(CH ₂ ) _f1 —CO—O— (f1 is an integer of 1 to 4), -O- is more preferred.
R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer from 0 to 3, more preferably 0 or 1.

上記構造単位においては、式（ａ２－１）中のＲ^ａ１４に相当するメチル基が水素原子に置き換わった化合物も、上記構造単位の具体例として挙げられる。
樹脂（Ａ）が構造単位（ａ２－１）を含む場合、その含有率は、樹脂（Ａ）の全構造単位の合計に対して、通常１～４５モル％であり、好ましくは１～４０モル％であり、より好ましくは１～３５モル％であり、さらに好ましくは２～２０モル％である。 The structural unit (a2-1) includes, for example, structural units derived from monomers described in JP-A-2010-204646, preferably the units of formulas (a2-1-1) to (a2- 1-3), more preferably a structural unit represented by any one of formulas (a2-1-1) to (a2-1-2).

Specific examples of the structural unit include compounds in which the methyl group corresponding to R ^a14 in formula (a2-1) is replaced with a hydrogen atom.
When the resin (A) contains the structural unit (a2-1), its content is usually 1 to 45 mol%, preferably 1 to 40 mol, based on the total of all structural units of the resin (A). %, more preferably 1 to 35 mol %, still more preferably 2 to 20 mol %.

<Structural unit (a3)>
The resin (A) of the present invention preferably has a structural unit (a3) in addition to the structural unit (a1).

The lactone ring of the structural unit (a3) may be a monocyclic ring such as a β-propiolactone ring, γ-butyrolactone ring, δ-valerolactone ring, or a condensed ring of a monocyclic lactone ring and another ring. It's okay. A bridged ring containing a γ-butyrolactone ring, an adamantanelactone ring or a γ-butyrolactone ring structure is preferred.

Structural unit (a3) is preferably a structural unit represented by formula (a3-1), formula (a3-2), formula (a3-3) or formula (a3-4). One of these may be contained alone, or two or more may be contained.

［式（ａ３－１）、式（ａ３－２）、式（ａ３－３）及び式（ａ３－４）中、
Ｌ^ａ４、Ｌ^ａ５及びＬ^ａ６は、－Ｏ－又は^＊－Ｏ－（ＣＨ_２）_ｋ３－ＣＯ－Ｏ－（ｋ３は１～７のいずれかの整数を表す。）で表される基を表す。
Ｌ^ａ７は、－Ｏ－、^＊－Ｏ－Ｌ^ａ８－Ｏ－、^＊－Ｏ－Ｌ^ａ８－ＣＯ－Ｏ－、^＊－Ｏ－Ｌ^ａ８－ＣＯ－Ｏ－Ｌ^ａ９－ＣＯ－Ｏ－又は^＊－Ｏ－Ｌ^ａ８－Ｏ－ＣＯ－Ｌ^ａ９－Ｏ－を表す。
Ｌ^ａ８及びＬ^ａ９は、互いに独立に、炭素数１～６のアルカンジイル基を表す。
＊はカルボニル基との結合手を表す。
Ｒ^ａ１８、Ｒ^ａ１９及びＲ^ａ２０は、水素原子又はメチル基を表す。
Ｒ^ａ２４は、ハロゲン原子を有してもよい炭素数１～６のアルキル基、水素原子又はハロゲン原子を表す。
Ｒ^ａ２１は炭素数１～４の脂肪族炭化水素基を表す。
Ｒ^ａ２２、Ｒ^ａ２３及びＲ^ａ２５は、カルボキシ基、シアノ基又は炭素数１～４の脂肪族炭化水素基を表す。
ｐ１は０～５のいずれかの整数を表す。
ｑ１は、０～３のいずれかの整数を表す。
ｒ１は、０～３のいずれかの整数を表す。
ｗ１は、０～８のいずれかの整数を表す。
ｐ１、ｑ１、ｒ１及び／又はｗ１が２以上のとき、複数のＲ^ａ２１、Ｒ^ａ２２、Ｒ^ａ２３及び／又はＲ^ａ２５は互いに同一であってもよく、異なってもよい。］

[In formula (a3-1), formula (a3-2), formula (a3-3) and formula (a3-4),
L ^a4 , L ^a5 and L ^a6 represent a group represented by —O— or ^* —O—(CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7); .
L ^a7 is -O-, ^* -OL ^a8 -O-, ^* -OL ^a8 -CO-O-, ^* -OL ^a8 -CO- ^{OL a9} -CO-O- or ^* -OL ^a8 -O-CO-L ^a9 -O-.
L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms.
* represents a bond with a carbonyl group.
R ^a18 , R ^a19 and R ^a20 each represent a hydrogen atom or a methyl group.
R ^a24 represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
R ^a22 , R ^a23 and R ^a25 each represent a carboxy group, a cyano group or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
p1 represents any integer from 0 to 5;
q1 represents an integer of 0 to 3;
r1 represents an integer of 0 to 3;
w1 represents any integer from 0 to 8;
When p1, q1, r1 and/or w1 are 2 or more, a plurality of R ^a21 , R ^a22 , R ^a23 and/or R ^a25 may be the same or different. ]

Examples of aliphatic hydrocarbon groups having 1 to 4 carbon atoms represented by R ^a21 , R ^a22 and R ^a23 include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, sec-butyl group and tert-butyl group. is mentioned.
Halogen atoms of R ^a24 include fluorine, chlorine, bromine and iodine atoms.
Examples of the alkyl group for R ^a24 include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group and n-hexyl group. , preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group.
The alkyl group having a halogen atom for R ^a24 includes a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, and a perfluoro A hexyl group, a trichloromethyl group, a tribromomethyl group, a triiodomethyl group and the like can be mentioned.

The alkanediyl groups of L ^a8 and L ^a9 include methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5 -diyl group, hexane-1,6-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1, 4-diyl group, 2-methylbutane-1,4-diyl group and the like.

（式中、Ｒ^ａ２４、Ｌ^ａ７は、上記と同じ意味を表す。） In formulas (a3-1) to (a3-4),
L ^a4 to L ^a6 are each independently a group preferably represented by —O— or *—O—(CH ₂ ) _k3 —CO—O— in which k3 is an integer of 1 to 4; , more preferably -O- and *-O-CH ₂ -CO-O-, more preferably an oxygen atom.
L ^a7 is preferably -O- or ^* -OL ^a8 -CO-O-, more preferably -O-, -O-CH ₂ -CO-O- or -O-C ₂ H ₄ - It is CO—O—.
R ^a18 to R ^a21 are preferably methyl groups.
R ^a24 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, still more preferably a hydrogen atom or a methyl group.
R ^a22 , R ^a23 and R ^a25 are each independently preferably a carboxy group, a cyano group or a methyl group.
Each of p1, q1, r1 and w1 is independently an integer preferably from 0 to 2, more preferably 0 or 1.
Formula (a3-4) is particularly preferably formula (a3-4)'.

(In the formula, R ^a24 and L ^a7 have the same meanings as above.)

As the monomer leading to the structural unit (a3), the monomer described in JP-A-2010-204646, the monomer described in JP-A-2000-122294, the monomer described in JP-A-2012-41274. mentioned. The structural unit (a3) is preferably a structural unit represented by any one of the following, and is represented by formula (a3-1-1), formula (a3-2-3) and formula (a3-4-1) to formula ( a3-4-12), more preferably a structural unit represented by any one of the formulas (a3-4-1) to (a3-4-12), and more preferably a structural unit represented by the formula Structural units represented by any one of formulas (a3-4-1) to (a3-4-6) are even more preferred.

上記構造単位においては、式（ａ３－１）～式（ａ３－４）中のＲ^ａ１８、Ｒ^ａ１９、Ｒ^ａ２０及びＲ^ａ２４に相当するメチル基が水素原子に置き換わった化合物も、構造単位（ａ３）の具体例として挙げられる。

In the above structural units, compounds in which the methyl groups corresponding to R ^a18 , R ^a19 , R ^a20 and R ^a24 in formulas (a3-1) to (a3-4) are replaced with hydrogen atoms are also structural unit (a3 ) as a specific example.

When the resin (A) contains the structural unit (a3), the total content is usually 5 to 70 mol%, preferably 10 to 65 mol%, based on the total of all structural units of the resin (A). and more preferably 10 to 60 mol %.
Further, the content of structural unit (a3-1), structural unit (a3-2), structural unit (a3-3) and structural unit (a3-4) is the total of all structural units of resin (A) It is preferably 5 to 60 mol %, more preferably 5 to 50 mol %, even more preferably 10 to 50 mol %, relative to the

<Structural unit (t)>
The structural unit (t) includes a structural unit (hereinafter sometimes referred to as “structural unit (a4)”) that may have a halogen atom other than the structural unit (a2) and the structural unit (a3). A structural unit having a hydrocarbon-free group (hereinafter sometimes referred to as "structural unit (a5)") and the like can be mentioned.

［式（ａ４－０）中、
Ｒ^５は、水素原子又はメチル基を表す。
Ｌ^５は、単結合又は炭素数１～４の脂肪族飽和炭化水素基を表す。
Ｌ^３は、炭素数１～８のペルフルオロアルカンジイル基又は炭素数３～１２のペルフルオロシクロアルカンジイル基を表す。
Ｒ^６は、水素原子又はフッ素原子を表す。］ Structural units (a4) include structural units represented by formula (a4-0).

[In the formula (a4-0),
^R5 represents a hydrogen atom or a methyl group.
L ⁵ represents a single bond or a C 1-4 saturated aliphatic hydrocarbon group.
L ³ represents a perfluoroalkanediyl group having 1 to 8 carbon atoms or a perfluorocycloalkanediyl group having 3 to 12 carbon atoms.
^R6 represents a hydrogen atom or a fluorine atom. ]

The saturated aliphatic hydrocarbon group for L ⁵ includes alkanediyl groups having 1 to 4 carbon atoms, such as methylene group, ethylene group, propane-1,3-diyl group and butane-1,4-diyl group. A straight-chain alkanediyl group such as a straight-chain alkanediyl group having a side chain of an alkyl group (especially a methyl group, an ethyl group, etc.), an ethane-1,1-diyl group, a propane-1, branched alkanediyl groups such as 2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group;

The perfluoroalkanediyl group for L ³ includes a difluoromethylene group, a perfluoroethylene group, a perfluoroethylfluoromethylene group, a perfluoropropane-1,3-diyl group, a perfluoropropane-1,2-diyl group, and a perfluoropropane-2,2 -diyl group, perfluorobutane-1,4-diyl group, perfluorobutane-2,2-diyl group, perfluorobutane-1,2-diyl group, perfluoropentane-1,5-diyl group, perfluoropentane-2,2 -diyl group, perfluoropentane-3,3-diyl group, perfluorohexane-1,6-diyl group, perfluorohexane-2,2-diyl group, perfluorohexane-3,3-diyl group, perfluoroheptane-1,7 -diyl group, perfluoroheptane-2,2-diyl group, perfluoroheptane-3,4-diyl group, perfluoroheptane-4,4-diyl group, perfluorooctane-1,8-diyl group, perfluorooctane-2,2 -diyl group, perfluorooctane-3,3-diyl group, perfluorooctane-4,4-diyl group and the like.
The perfluorocycloalkanediyl group for L ³ includes a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group, a perfluoroadamantanediyl group, and the like.

^L5 is preferably a single bond, a methylene group or an ethylene group, more preferably a single bond or a methylene group.
L ³ is preferably a C 1-6 perfluoroalkanediyl group, more preferably a C 1-3 perfluoroalkanediyl group.

Examples of the structural unit (a4-0) include structural units shown below.

上記の構造単位において、式（ａ４－０）中のＲ⁵に相当するメチル基が水素原子に置き換わった構造単位も、構造単位（ａ４－０）の具体例として挙げることができる。

In the above structural unit, a structural unit in which the methyl group corresponding to R ⁵ in formula (a4-0) is replaced with a hydrogen atom can also be mentioned as a specific example of structural unit (a4-0).

［式（ａ４－１）中、
Ｒ^ａ４１は、水素原子又はメチル基を表す。
Ｒ^ａ４２は、置換基を有していてもよい炭素数１～２０の炭化水素基を表し、該炭化水素基に含まれる－ＣＨ_２－は、－Ｏ－又は－ＣＯ－に置き換わっていてもよい。
Ａ^ａ４１は、置換基を有していてもよい炭素数１～６のアルカンジイル基又は式（ａ－ｇ１）で表される基を表す。］

［式（ａ－ｇ１）中、
ｓは０又は１を表す。
Ａ^ａ４２及びＡ^ａ４４は、それぞれ独立に、置換基を有していてもよい炭素数１～５の２価の脂肪族炭化水素基を表す。
Ａ^ａ４３は、単結合又は置換基を有していてもよい炭素数１～５の２価の脂肪族炭化水素基を表す。
Ｘ^ａ４１及びＸ^ａ４２は、それぞれ独立に、－Ｏ－、－ＣＯ－、－ＣＯ－Ｏ－又は－Ｏ－ＣＯ－を表す。
ただし、Ａ^ａ４２、Ａ^ａ４３、Ａ^ａ４４、Ｘ^ａ４１及びＸ^ａ４２の炭素数の合計は７以下である。
＊で表される２つの結合手のうち、右側の＊が－Ｏ－ＣＯ－Ｒ^ａ４２との結合手である。］ Structural units (a4) include structural units represented by formula (a4-1).

[In formula (a4-1),
R ^a41 represents a hydrogen atom or a methyl group.
R ^a42 represents an optionally substituted hydrocarbon group having 1 to 20 carbon atoms, and —CH ₂ — contained in the hydrocarbon group may be replaced with —O— or —CO— good.
A ^a41 represents an optionally substituted alkanediyl group having 1 to 6 carbon atoms or a group represented by formula (a-g1). ]

[In the formula (a-g1),
s represents 0 or 1;
A ^a42 and A ^a44 each independently represent a divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a substituent.
A ^a43 represents a single bond or an optionally substituted C 1-5 divalent aliphatic hydrocarbon group.
X ^a41 and X ^a42 each independently represent -O-, -CO-, -CO-O- or -O-CO-.
However, the total number of carbon atoms of A ^a42 , A ^a43 , A ^a44 , X ^a41 and X ^a42 is 7 or less.
Of the two bonds represented by *, the * on the right is the bond with —O—CO—R ^a42 . ]

The hydrocarbon group for R ^a42 includes chain and cyclic aliphatic hydrocarbon groups, aromatic hydrocarbon groups, and groups formed by combinations thereof.
Acyclic and cyclic aliphatic hydrocarbon groups may have carbon-carbon unsaturated bonds, but are formed by saturated acyclic and cyclic aliphatic hydrocarbon groups and combinations thereof. groups are preferred. The aliphatic saturated hydrocarbon group includes a linear or branched alkyl group, a monocyclic or polycyclic alicyclic hydrocarbon group, and an aliphatic hydrocarbon group formed by combining an alkyl group and an alicyclic hydrocarbon group. group hydrocarbon groups and the like.

Chain type aliphatic hydrocarbon groups include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group and n-decyl. n-dodecyl, n-pentadecyl, n-hexadecyl, n-heptadecyl and n-octadecyl groups. Cyclic aliphatic hydrocarbon groups include cycloalkyl groups such as cyclopentyl, cyclohexyl, cycloheptyl and cyclooctyl; decahydronaphthyl, adamantyl, norbornyl and the following groups (* indicates a bond represents a hand.) and other polycyclic alicyclic hydrocarbon groups.

Aromatic hydrocarbon groups include phenyl, naphthyl, anthryl, biphenylyl, phenanthryl and fluorenyl groups.

［式（ａ－ｇ３）中、
Ｘ^ａ４３は、酸素原子、カルボニル基、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ^ａ４５は、少なくとも１つのハロゲン原子を有する炭素数１～１７の脂肪族炭化水素基を表す。
＊は結合手を表す。］ Substituents for R ^a42 include halogen atoms and groups represented by formula (a-g3). A halogen atom includes a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, preferably a fluorine atom.

[In the formula (a-g3),
^Xa43 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ^a45 represents a C 1-17 aliphatic hydrocarbon group having at least one halogen atom.
* represents a bond. ]

Examples of the aliphatic hydrocarbon group for A ^a45 include groups similar to those exemplified for R ^a42 .
R ^a42 is preferably an aliphatic hydrocarbon group which may have a halogen atom, an alkyl group having a halogen atom and/or an aliphatic hydrocarbon group having a group represented by formula (a-g3) is more preferable.
When R ^a42 is an aliphatic hydrocarbon group having a halogen atom, R ^a42 is preferably an aliphatic hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, still more preferably It is a perfluoroalkyl group having 1 to 6 carbon atoms, and particularly preferably a perfluoroalkyl group having 1 to 3 carbon atoms. Perfluoroalkyl groups include perfluoromethyl, perfluoroethyl, perfluoropropyl, perfluorobutyl, perfluoropentyl, perfluorohexyl, perfluoroheptyl and perfluorooctyl groups. A perfluorocyclohexyl group etc. are mentioned as a perfluorocycloalkyl group.
When R ^a42 is an aliphatic hydrocarbon group having a group represented by formula (a-g3), including the number of carbon atoms contained in the group represented by formula (a-g3), the aliphatic hydrocarbon The total number of carbon atoms in the group is preferably 15 or less, more preferably 12 or less. When it has a group represented by formula (a-g3) as a substituent, the number thereof is preferably one.

A more preferred structure of the group represented by formula (a-g3) is the following structure.

The alkanediyl group for A ^a41 includes methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, and hexane-1,6-diyl group. straight-chain alkanediyl groups such as; A branched alkanediyl group such as a 2-methylbutane-1,4-diyl group can be mentioned.
Examples of substituents on the alkanediyl group of A ^a41 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
^Aa41 is preferably an alkanediyl group having 1 to 4 carbon atoms, more preferably an alkanediyl group having 2 to 4 carbon atoms, and still more preferably an ethylene group.

The aliphatic hydrocarbon groups of A ^a42 , A ^a43 and A ^a44 in group (a-g1) may have a carbon-carbon unsaturated bond, but are preferably saturated aliphatic hydrocarbon groups.
As the aliphatic saturated hydrocarbon group, an alkyl group (the alkyl group may be linear or branched) and an alicyclic hydrocarbon group, and a combination of an alkyl group and an alicyclic hydrocarbon group and an aliphatic hydrocarbon group formed by. Specifically, methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group and the like.
Substituents of the aliphatic hydrocarbon groups of A ^a42 , A ^a43 and A ^a44 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
s is preferably zero.

Examples of the group (a-g1) in which X ^a42 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group include the following groups. In the following examples, * and ** each represent a bond, and ** is a bond with --O--CO--R ^a42 .

Examples of structural units represented by formula (a4-1) include the following structural units and structural units in which a methyl group corresponding to R ^a41 in formula (a4-1) is replaced with a hydrogen atom.

［式（ａ４－４）中、
Ｒ^ｆ２１は、水素原子又はメチル基を表す。
Ａ^ｆ２１は、－（ＣＨ_２）_ｊ１－、－（ＣＨ_２）_ｊ２－Ｏ－（ＣＨ_２）_ｊ３－又は－（ＣＨ_２）_ｊ４－ＣＯ－Ｏ－（ＣＨ_２）_ｊ５－を表す。
ｊ１～ｊ５は、それぞれ独立に、１～６のいずれかの整数を表す。
Ｒ^ｆ２２は、フッ素原子を有する炭素数１～１０の炭化水素基を表す。］ Structural units (a4) also include structural units represented by formula (a4-4).

[In formula (a4-4),
R ^f21 represents a hydrogen atom or a methyl group.
A ^f21 represents -(CH ₂ ) _j1 -, -(CH ₂ ) _j2 -O-(CH ₂ ) _j3 - or -(CH ₂ ) _j4 -CO-O-(CH ₂ ) _j5 -.
j1 to j5 each independently represent an integer of 1 to 6;
R ^f22 represents a hydrocarbon group having 1 to 10 carbon atoms and having a fluorine atom. ]

The hydrocarbon group having a fluorine atom for R ^f22 includes an alkyl group having a fluorine atom and having 1 to 10 carbon atoms or an alicyclic hydrocarbon group having a fluorine atom and having 3 to 10 carbon atoms. Specifically, difluoromethyl group, trifluoromethyl group, 1,1-difluoroethyl group, 2,2-difluoroethyl group, 2,2,2-trifluoroethyl group, perfluoroethyl group, 1,1,2 ,2-tetrafluoropropyl group, 1,1,2,2,3,3-hexafluoropropyl group, perfluoroethylmethyl group, 1-(trifluoromethyl)-1,2,2,2-tetrafluoroethyl group , 1-(trifluoromethyl)-2,2,2-trifluoroethyl group, perfluoropropyl group, 1,1,2,2-tetrafluorobutyl group, 1,1,2,2,3,3-hexa fluorobutyl group, 1,1,2,2,3,3,4,4-octafluorobutyl group, perfluorobutyl group, 1,1-bis(trifluoro)methyl-2,2,2-trifluoroethyl group , 2-(perfluoropropyl)ethyl group, 1,1,2,2,3,3,4,4-octafluoropentyl group, perfluoropentyl group, 1,1,2,2,3,3,4,4 , 5,5-decafluoropentyl group, 1,1-bis(trifluoromethyl)-2,2,3,3,3-pentafluoropropyl group, 2-(perfluorobutyl)ethyl group, 1,1,2 , 2,3,3,4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexyl group, perfluoro Pentylmethyl group, perfluorohexyl group, perfluorocyclohexyl group, perfluoroadamantyl group and the like. An alkyl group having 1 to 10 carbon atoms and having a fluorine atom is preferable, and an alkyl group having 1 to 6 carbon atoms and having a fluorine atom is more preferable.

In formula (a4-4), A ^f21 is preferably —(CH ₂ ) _j1 —, more preferably an ethylene group or a methylene group, and still more preferably a methylene group.

樹脂（Ａ）が、構造単位（ａ４）を有する場合、その含有率は、樹脂（Ａ）の全構造単位の合計に対して、１～２０モル％であることが好ましく、２～１５モル％であることがより好ましく、３～１０モル％であることがさらに好ましい。 Examples of structural units represented by formula (a4-4) include the following structural units and structural units in which a methyl group corresponding to R ^f21 in formula (a4-4) is replaced with a hydrogen atom.

When the resin (A) has the structural unit (a4), the content thereof is preferably 1 to 20 mol%, preferably 2 to 15 mol%, based on the total of all structural units of the resin (A). and more preferably 3 to 10 mol %.

［式（ａ５－１）中、
Ｒ^５１は、水素原子又はメチル基を表す。
Ｒ^５２は、炭素数３～１８の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれる水素原子は炭素数１～８の脂肪族炭化水素基又はヒドロキシ基で置換されていてもよい。
但し、Ｌ^５５との結合位置にある炭素原子に結合する水素原子は、炭素数１～８の脂肪族炭化水素基で置換されない。
Ｌ^５５は、単結合又は炭素数１～１８の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。］ <Structural unit (a5)>
Examples of non-leaving hydrocarbon groups possessed by the structural unit (a5) include linear, branched and cyclic hydrocarbon groups. Among them, the structural unit (a5) is preferably a group having an alicyclic hydrocarbon group.
Examples of the structural unit (a5) include structural units represented by formula (a5-1).

[In the formula (a5-1),
^R51 represents a hydrogen atom or a methyl group.
R ⁵² represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and a hydrogen atom contained in the alicyclic hydrocarbon group is substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms or a hydroxy group. may
However, the hydrogen atom bonded to the carbon atom at the bonding position with L ⁵⁵ is not substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms.
L ⁵⁵ represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group. ]

The alicyclic hydrocarbon group for R ⁵² may be either monocyclic or polycyclic. Examples of monocyclic alicyclic hydrocarbon groups include cyclopropyl, cyclobutyl, cyclopentyl and cyclohexyl groups. Examples of polycyclic alicyclic hydrocarbon groups include adamantyl groups and norbornyl groups.
Examples of aliphatic hydrocarbon groups having 1 to 8 carbon atoms include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group and hexyl group. , octyl and 2-ethylhexyl groups.
The substituted alicyclic hydrocarbon group includes a 3-hydroxyadamantyl group and a 3-methyladamantyl group.
R ⁵² is preferably an unsubstituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, more preferably an adamantyl group, a norbornyl group or a cyclohexyl group.

The divalent saturated hydrocarbon group for L ⁵⁵ includes a divalent aliphatic saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, preferably a divalent aliphatic saturated hydrocarbon group. be done.
Examples of divalent aliphatic saturated hydrocarbon groups include alkanediyl groups such as methylene, ethylene, propanediyl, butanediyl and pentanediyl groups.
The bivalent alicyclic saturated hydrocarbon group may be either monocyclic or polycyclic. The monocyclic alicyclic saturated hydrocarbon group includes cycloalkanediyl groups such as cyclopentanediyl group and cyclohexanediyl group. The polycyclic divalent alicyclic saturated hydrocarbon group includes an adamantanediyl group and a norbornanediyl group.

Examples of the group in which the methylene group contained in the saturated hydrocarbon group is replaced with an oxygen atom or a carbonyl group include the groups shown below. In the following formula, * represents a bond with an oxygen atom.

Examples of the structural unit (a5-1) include the following and structural units in which the methyl group corresponding to R ⁵¹ in formula (a5-1) is replaced with a hydrogen atom.

When the resin (A) has the structural unit (a5), the content thereof is preferably 1 to 30 mol%, preferably 2 to 20 mol%, based on the total of all structural units of the resin (A). and more preferably 3 to 15 mol %.

The resin (A) is a resin comprising a structural unit (a1) and a structural unit having no acid-labile group, a structural unit (a1), a structural unit having no acid-labile group, and a structural unit (t). More preferably, it is a resin comprising a structural unit (a1) and a structural unit having no acid-labile group.

Structural unit (a1) is preferably at least selected from structural unit (a1-0), structural unit (a1-1) and structural unit (a1-2) (preferably the structural unit having a cyclohexyl group or a cyclopentyl group) one kind, more preferably at least two kinds selected from structural unit (a1-0), structural unit (a1-1) and structural unit (a1-2) (preferably the structural unit having a cyclohexyl group or a cyclopentyl group) is.
The structural unit having no acid labile group is preferably at least one of structural unit (a2) and structural unit (a3). Structural unit (a2) is preferably a structural unit represented by formula (a2-1). Structural unit (a3) is preferably selected from structural units represented by formula (a3-1), structural units represented by formula (a3-2) and structural units represented by formula (a3-4) at least one.
Structural unit (t) is preferably a structural unit containing a fluorine atom, such as structural unit (a4).

Each structural unit that constitutes the resin (A) may be used alone or in combination of two or more. Using a monomer that induces these structural units, it is produced by a known polymerization method (e.g., radical polymerization method). can do. The content of each structural unit in the resin (A) can be adjusted by adjusting the amount of monomer used for polymerization.
The weight average molecular weight of the resin (A) is preferably 2,000 or more (more preferably 2,500 or more, still more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less, further preferably 15,000 or less).
As used herein, the weight average molecular weight is a value determined by gel permeation chromatography. Gel permeation chromatography can be measured under the analysis conditions described in Examples.

<Resin (X)>
The resin (X) includes, for example, a resin containing the structural unit (t), preferably a resin containing the structural unit (a4) (but not containing the structural unit (a1)), and has a structure having a fluorine atom. Unit (a4) is more preferred. In the resin (X), the content of the structural unit (a4) is preferably 40 mol% or more, more preferably 45 mol% or more, and even more preferably 50 mol% or more, based on the total structural units of the resin (X). .
Structural units that the resin (X) may further include structural units (a2), structural units (a3), and structural units derived from other known monomers.
The weight average molecular weight of resin (X) is preferably 8,000 or more (more preferably 10,000 or more) and 80,000 or less (more preferably 60,000 or less). The means for measuring the weight-average molecular weight of resin (X) is the same as for resin (A).
When the resist composition contains resin (X), its content is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, relative to 100 parts by mass of resin (A). It is preferably 1 to 40 parts by mass, particularly preferably 2 to 30 parts by mass, and most preferably 2 to 10 parts by mass.

When the resist composition contains the resin (A) and the resin (X), the total content of the resin (A) and the resin (X) is 80% by mass or more and 99% by mass with respect to the solid content of the resist composition. % or less is preferable. The solid content and resin content of the resist composition can be measured by known analytical means such as liquid chromatography or gas chromatography.

<Acid generator>
The acid generator may contain one or two or more acid generators (I) as active ingredients, or known acid generators in the field of resists ( hereinafter sometimes referred to as "acid generator (B)").
When acid generator (I) and acid generator (B) are contained as acid generators, the ratio of the contents of acid generator (I) and acid generator (B) (mass ratio, acid generator ( I): acid generator (B)) is usually 1:99-99:1, preferably 2:98-98:2, more preferably 5:95-95:5.

<Acid Generator (I)>
The acid generator (I) may be either nonionic or ionic.
Nonionic acid generators include organic halides, sulfonate esters (eg, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 4-sulfonate), sulfones (eg, disulfone, ketosulfone, sulfonyldiazomethane) and the like. Typical ionic acid generators are onium salts containing onium cations (for example, diazonium salts, phosphonium salts, sulfonium salts and iodonium salts). The anions of the onium salts include sulfonate anions, sulfonylimide anions, sulfonylmethide anions, and the like.

［式（ａａ）中、
Ｘ^a及びＸ^bは、それぞれ独立に、酸素原子又は硫黄原子を表す。
Ｘ¹は、環の構成要素として－Ｏ－ＳＯ－Ｏ－を含む環構造を有する２価の基を表し、該２価の基に含まれる水素原子は、ヒドロキシ基で置換されていてもよい。
＊は、結合手を表す。］ The acid generated from the acid generator (I) is preferably an acid having a ring structure containing -O-SO-O- as a ring constituent, and the acid is an acid having the following groups: is more preferred.

[in the formula (aa),
X ^a and X ^b each independently represent an oxygen atom or a sulfur atom.
X ¹ represents a divalent group having a ring structure containing —O—SO—O— as a ring constituent, and a hydrogen atom contained in the divalent group may be substituted with a hydroxy group. .
* represents a bond. ]

X ^a and X ^b are preferably the same atom, more preferably an oxygen atom.
One or more ring structures containing —O—SO—O— in X ¹ may be present.

The bivalent group having a ring structure containing -O-SO-O- as a ring constituent includes a monocyclic or condensed ring, a polycyclic divalent heterocyclic group including a spiro ring and a ring assembly, A group obtained by combining this heterocyclic group with an alkanediyl group, a group obtained by combining three or more types of a heterocyclic group and an alkanediyl group, and the like.
Among them, the ring structure containing —O—SO—O— as a ring constituent , that is, the group represented by the formula (aa) preferably includes the following groups.

［式（ａａ１）中、
Ｘ^a、Ｘ^b、Ｘ¹及び＊は、上記と同じ意味を表す。
環Ｗは、置換基を有していてもよい炭素数３～３６の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれるメチレン基は、酸素原子、硫黄原子、カルボニル基又はスルホニル基で置換されていてもよい。］ Acid generator (I) is preferably a salt having a group represented by formula (aa1).

[In the formula (aa1),
X ^a , X ^b , X ¹ and * have the same meanings as above.
Ring W represents an optionally substituted alicyclic hydrocarbon group having 3 to 36 carbon atoms, and the methylene group contained in the alicyclic hydrocarbon group is an oxygen atom, a sulfur atom, or a carbonyl group. Or it may be substituted with a sulfonyl group. ]

The alicyclic hydrocarbon group having 3 to 36 carbon atoms in ring W may have a substituent, and examples of the substituent include groups described in group A.
Group A: a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, an aromatic hydrocarbon group having 6=10 carbon atoms, or these combination of

［式（ａ１－１）～式（ａ１－１２）中、
環に含まれるメチレン基は酸素原子、硫黄原子、カルボニル基又はスルホニル基で置換されていてもよく、環に含まれる水素原子は上記群Ａに記載の基で置換されていてもよい。］
式（ａ１－１）～式（ａ１－１２）で表される環においては、任意に２つの水素原子が除去されてＸ^a及びＸ^bとの結合手とすればよい。 Examples of the alicyclic hydrocarbon group having 3 to 36 carbon atoms in ring W include rings represented by formulas (a1-1) to (a1-12), and alicyclic carbonization having 3 to 18 carbon atoms. A hydrogen group is preferable, and a ring represented by formula (a1-1), a ring represented by formula (a1-2) or a ring represented by formula (a1-3) is more preferable.

[In the formulas (a1-1) to (a1-12),
A methylene group contained in the ring may be substituted with an oxygen atom, a sulfur atom, a carbonyl group or a sulfonyl group, and a hydrogen atom contained in the ring may be substituted with a group described in Group A above. ]
In the rings represented by formulas (a1-1) to (a1-12), two hydrogen atoms may optionally be removed to form bonds with X ^a and X ^b .

群Ａにおける炭素数６～１０の芳香族炭化水素基としては、フェニル基、ナフチル基が挙げられる。 Examples of alkyl groups having 1 to 12 carbon atoms in Group A include methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group, and the like. are mentioned.
The alkoxy groups having 1 to 12 carbon atoms in Group A include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, octyloxy, 2-ethylhexyloxy, nonyloxy, decyloxy, An undecyloxy group, a dodecyloxy group and the like can be mentioned.
Examples of the alicyclic hydrocarbon group having 3 to 12 carbon atoms in Group A include the groups shown below. * is a bond with a ring.

Examples of the aromatic hydrocarbon group having 6 to 10 carbon atoms in Group A include a phenyl group and a naphthyl group.

The acid generator (I) is preferably a salt comprising an anion having a group represented by formula (aa1) and a cation, and an anion having a group represented by formula (a) and an organic cation. More preferably, it is a salt consisting of

［式（ａａ２）中、
Ｘ^a、Ｘ^b、Ｘ¹及びＷは、上記と同じ意味を表す。
Ｌ^b1は、炭素数１～２４の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよく、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基で置換されていてもよい。
Ｑ¹及びＱ²は、互いに独立に、フッ素原子又は炭素数１～６のペルフルオロアルキル基を表す。］ The anion having a group represented by formula (aa1) is preferably an anion represented by formula (aa2).

[In formula (aa2),
X ^a , X ^b , X ¹ and W have the same meanings as above.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, the methylene group contained in the saturated hydrocarbon group may be replaced by an oxygen atom or a carbonyl group, The contained hydrogen atoms may be substituted with fluorine atoms or hydroxy groups.
Q ¹ and Q ² independently represent a fluorine atom or a C 1-6 perfluoroalkyl group. ]

Perfluoroalkyl groups represented by Q ¹ and Q ² include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group and a perfluoropentyl group. groups and perfluorohexyl groups.
Q ¹ and Q ² are each independently preferably a fluorine atom or a trifluoromethyl group, and both Q ¹ and Q ² are more preferably fluorine atoms.

The divalent saturated hydrocarbon group represented by L ^b1 includes an alkanediyl group, a monocyclic or polycyclic bivalent alicyclic saturated hydrocarbon group, and two or more of these groups may be a combination of
Specifically, methylene group, ethylene group, propane-1,3-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, hexane-1,6-diyl group, heptane-1 ,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11-diyl group, dodecane-1,12-diyl group , tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group and heptadecane-1,17-diyl group. alkanediyl group;
ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, 2-methylpropane- Branched alkanediyl groups such as 1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, and 2-methylbutane-1,4-diyl group;
monocyclic 2 which is a cycloalkanediyl group such as cyclobutane-1,3-diyl group, cyclopentane-1,3-diyl group, cyclohexane-1,4-diyl group, cyclooctane-1,5-diyl group; alicyclic saturated hydrocarbon group;
Polycyclic divalent alicyclic saturated hydrocarbons such as norbornane-1,4-diyl group, norbornane-2,5-diyl group, adamantane-1,5-diyl group, and adamantane-2,6-diyl group and the like.

式（ｂ１－１）中、
Ｌ^b2は、単結合又は炭素数１～２２の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b3は、単結合又は炭素数１～２２の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよく、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
ただし、Ｌ^b2とＬ^b3との炭素数合計は、２２以下である。
式（ｂ１－２）中、
Ｌ^b4は、単結合又は炭素数１～２２の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b5は、単結合又は炭素数１～２２の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよく、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
ただし、Ｌ^b4とＬ^b5との炭素数合計は、２２以下である。
式（ｂ１－３）中、
Ｌ^b6は、単結合又は炭素数１～２３の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
Ｌ^b7は、単結合又は炭素数１～２３の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよく、該飽和炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
ただし、Ｌ^b6とＬ^b7との炭素数合計は、２３以下である。
＊はＷとの結合手を表す。 The group in which —CH ₂ — contained in the divalent saturated hydrocarbon group represented by L ^b1 is replaced with —O— or —CO— is any one of formulas (b1-1) to (b1-3). The group represented by is mentioned. In formulas (b1-1) to (b1-3) and specific examples below, * represents a bond with -W.

In formula (b1-1),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b3 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated A methylene group contained in the hydrocarbon group may be substituted with an oxygen atom or a carbonyl group.
However, the total number of carbon atoms of L ^b2 and L ^b3 is 22 or less.
In formula (b1-2),
L ^b4 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group; A methylene group contained in the hydrocarbon group may be substituted with an oxygen atom or a carbonyl group.
However, the total number of carbon atoms of L ^b4 and L ^b5 is 22 or less.
In formula (b1-3),
L ^b6 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
L ^b7 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated A methylene group contained in the hydrocarbon group may be substituted with an oxygen atom or a carbonyl group.
However, the total number of carbon atoms of L ^b6 and L ^b7 is 23 or less.
* represents a bond with W.

In formulas (b1-1) to (b1-3), when the methylene group contained in the saturated hydrocarbon group is replaced with an oxygen atom or a carbonyl group, the number of carbon atoms before the replacement is the saturated hydrocarbon group. is the carbon number of
As the divalent saturated hydrocarbon group, the same divalent saturated hydrocarbon group as L ^b1 can be mentioned.

L ^b2 is preferably a single bond.
L ^b3 is preferably a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.
L ^b4 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b5 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b6 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b7 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. , the methylene group contained in the saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
Among them, a group represented by formula (b1-1) or formula (b1-3) is preferable.

式（ｂ１－４）中、
Ｌ^b8は、単結合又は炭素数１～２２の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
式（ｂ１－５）中、
Ｌ^b9は、炭素数１～２０の２価の飽和炭化水素基を表す。
Ｌ^b10は、単結合又は炭素数１～１９の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b9及びＬ^b10の合計炭素数は２０以下である。
式（ｂ１－６）中、
Ｌ^b11は、炭素数１～２１の２価の飽和炭化水素基を表す。
Ｌ^b12は、単結合又は炭素数１～２０の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b11及びＬ^b12の合計炭素数は２１以下である。
式（ｂ１－７）中、
Ｌ^b13は、炭素数１～１９の２価の飽和炭化水素基を表す。
Ｌ^b14は、単結合又は炭素数１～１８の２価の飽和炭化水素基を表す。
Ｌ^b15は、単結合又は炭素数１～１８の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b13、Ｌ^b14及びＬ^b15の合計炭素数は１９以下である。
式（ｂ１－８）中、
Ｌ^b16は、炭素数１～１８の２価の飽和炭化水素基を表す。
Ｌ^b17は、炭素数１～１８の２価の飽和炭化水素基を表す。
Ｌ^b18は、単結合又は炭素数１～１７の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子又はヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b16、Ｌ^b17及びＬ^b18の合計炭素数は１９以下である。
＊はＷとの結合手を表す。 Examples of formula (b1-1) include groups represented by formulas (b1-4) to (b1-8).

In formula (b1-4),
L ^b8 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
In formula (b1-5),
L ^b9 represents a divalent saturated hydrocarbon group having 1 to 20 carbon atoms.
L ^b10 represents a single bond or a divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total carbon number of L ^b9 and L ^b10 is 20 or less.
In formula (b1-6),
L ^b11 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b12 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total carbon number of L ^b11 and L ^b12 is 21 or less.
In formula (b1-7),
L ^b13 represents a divalent saturated hydrocarbon group having 1 to 19 carbon atoms.
L ^b14 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b15 represents a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total carbon number of L ^b13 , L ^b14 and L ^b15 is 19 or less.
In formula (b1-8),
L ^b16 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b17 represents a divalent saturated hydrocarbon group having 1 to 18 carbon atoms.
L ^b18 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
However, the total carbon number of L ^b16 , L ^b17 and L ^b18 is 19 or less.
* represents a bond with W.

L ^b8 is preferably a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.
L ^b9 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b10 is preferably a single bond or a C 1-19 divalent saturated hydrocarbon group, more preferably a single bond or a C 1-8 divalent saturated hydrocarbon group.
L ^b11 is preferably a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b12 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b13 is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b14 is preferably a single bond or a C 1-6 divalent saturated hydrocarbon group.
L ^b15 is preferably a single bond or a C 1-18 divalent saturated hydrocarbon group, more preferably a single bond or a C 1-8 divalent saturated hydrocarbon group.
L ^b16 preferably represents a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b17 preferably represents a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
L ^b18 is preferably a single bond or a C 1-17 divalent saturated hydrocarbon group, more preferably a single bond or a C 1-4 divalent saturated hydrocarbon group.

式（ｂ１－９）中、
Ｌ^b19は、単結合又は炭素数１～２３の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b20は、単結合又は炭素数１～２３の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子、ヒドロキシ基又はアシルオキシ基に置換されていてもよい。該アシルオキシ基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよく、該アシルオキシ基に含まれる水素原子は、ヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b19及びＬ^b20の合計炭素数は２３以下である。
式（ｂ１－１０）中、
Ｌ^b21は、単結合又は炭素数１～２１の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b22は、単結合又は炭素数１～２１の２価の飽和炭化水素基を表す。
Ｌ^b23は、単結合又は炭素数１～２１の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子、ヒドロキシ基又はアシルオキシ基に置換されていてもよい。該アシルオキシ基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよく、該アシルオキシ基に含まれる水素原子は、ヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b21、Ｌ^b22及びＬ^b23の合計炭素数は２１以下である。
式（ｂ１－１１）中、
Ｌ^b24は、単結合又は炭素数１～２０の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子に置換されていてもよい。
Ｌ^b25は、炭素数１～２１の２価の飽和炭化水素基を表す。
Ｌ^b26は、単結合又は炭素数１～２０の２価の飽和炭化水素基を表し、該飽和炭化水素基に含まれる水素原子は、フッ素原子、ヒドロキシ基又はアシルオキシ基に置換されていてもよい。該アシルオキシ基に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよく、該アシルオキシ基に含まれる水素原子は、ヒドロキシ基に置換されていてもよい。
ただし、Ｌ^b24、Ｌ^b25及びＬ^b26の合計炭素数は２１以下である。
＊はＷとの結合手を表す。 Examples of formula (b1-3) include groups represented by formulas (b1-9) to (b1-11).

In formula (b1-9),
L ^b19 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b20 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxy group or an acyloxy group. . A methylene group contained in the acyloxy group may be substituted with an oxygen atom or a carbonyl group, and a hydrogen atom contained in the acyloxy group may be substituted with a hydroxy group.
However, the total carbon number of L ^b19 and L ^b20 is 23 or less.
In formula (b1-10),
L ^b21 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b22 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b23 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxy group or an acyloxy group. . A methylene group contained in the acyloxy group may be substituted with an oxygen atom or a carbonyl group, and a hydrogen atom contained in the acyloxy group may be substituted with a hydroxy group.
However, the total carbon number of L ^b21 , L ^b22 and L ^b23 is 21 or less.
In formula (b1-11),
L ^b24 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b25 represents a divalent saturated hydrocarbon group having 1 to 21 carbon atoms.
L ^b26 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and a hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom, a hydroxy group or an acyloxy group. . A methylene group contained in the acyloxy group may be substituted with an oxygen atom or a carbonyl group, and a hydrogen atom contained in the acyloxy group may be substituted with a hydroxy group.
However, the total carbon number of L ^b24 , L ^b25 and L ^b26 is 21 or less.
* represents a bond with W.

In formulas (b1-9) to (b1-11), when the hydrogen atom contained in the saturated hydrocarbon group is substituted with an acyloxy group, the carbon number of the acyloxy group, the CO and O and the number of carbon atoms in the saturated hydrocarbon group.

Acyloxy groups include acetyloxy, propionyloxy, butyryloxy, cyclohexylcarbonyloxy, and adamantylcarbonyloxy groups.

Among the groups represented by formula (b1-1), the groups represented by formula (b1-4) include the following.

Among the groups represented by formula (b1-1), the groups represented by formula (b1-5) include the following.

Among the groups represented by formula (b1-1), the groups represented by formula (b1-6) include the following.

Among the groups represented by formula (b1-1), the groups represented by formula (b1-7) include the following.

Among the groups represented by formula (b1-1), the groups represented by formula (b1-8) include the following.

Examples of the group represented by formula (b1-2) include the following.

Among the groups represented by formula (b1-3), the groups represented by formula (b1-9) include the following.

Among the groups represented by formula (b1-3), the groups represented by formula (b1-10) include the following.

Among the groups represented by formula (b1-3), the groups represented by formula (b1-11) include the following.

Examples of the anion represented by formula (aa2) include the following.

The cation in the acid generator (I) is preferably an organic cation. Organic cations include organic onium cations, organic sulfonium cations, organic iodonium cations, organic ammonium cations, benzothiazolium cations and organic phosphonium cations. Among these, organic sulfonium cations and organic iodonium cations are preferred, and arylsulfonium cations are more preferred.
Among them, cations represented by any one of formulas (b2-1) to (b2-4) (hereinafter sometimes referred to as "cation (b2-1)" and the like depending on the formula number) are preferred.

式（ｂ２－１）～式（ｂ２－４）において、
Ｒ^b4～Ｒ^b6は、それぞれ独立に、炭素数１～３０の脂肪族炭化水素基、炭素数３～３６の脂環式炭化水素基又は炭素数６～３６の芳香族炭化水素基を表し、該脂肪族炭化水素基に含まれる水素原子は、ヒドロキシ基、炭素数１～１２のアルコキシ基、炭素数３～１２の脂環式炭化水素基又は炭素数６～１８の芳香族炭化水素基で置換されていてもよく、該脂環式炭化水素基に含まれる水素原子は、ハロゲン原子、炭素数１～１８の脂肪族炭化水素基、炭素数２～４のアシル基又はグリシジルオキシ基で置換されていてもよく、該芳香族炭化水素基に含まれる水素原子は、ハロゲン原子、ヒドロキシ基又は炭素数１～１２のアルコキシ基で置換されていてもよい。
Ｒ^b4とＲ^b5とは、一緒になってそれらが結合する硫黄原子を含む環を形成してもよく、該環に含まれるメチレン基は、酸素原子、スルフィニル基又はカルボニル基に置き換わってもよい。

In formulas (b2-1) to (b2-4),
R ^b4 to R ^b6 each independently represents an aliphatic hydrocarbon group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms or an aromatic hydrocarbon group having 6 to 36 carbon atoms; The hydrogen atom contained in the aliphatic hydrocarbon group is a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. It may be substituted, and the hydrogen atoms contained in the alicyclic hydrocarbon group are substituted with a halogen atom, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, an acyl group having 2 to 4 carbon atoms, or a glycidyloxy group. A hydrogen atom contained in the aromatic hydrocarbon group may be substituted with a halogen atom, a hydroxy group, or an alkoxy group having 1 to 12 carbon atoms.
R ^b4 and R ^b5 may together form a ring containing a sulfur atom to which they are bonded, and the methylene group contained in the ring may be replaced by an oxygen atom, a sulfinyl group or a carbonyl group. .

R ^b7 and R ^b8 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represent an integer of 0 to 5;
When m2 is 2 or more, multiple R ^b7 may be the same or different, and when n2 is 2 or more, multiple R ^b8 may be the same or different.

R ^b9 and R ^b10 each independently represent an aliphatic hydrocarbon group having 1 to 36 carbon atoms or an alicyclic hydrocarbon group having 3 to 36 carbon atoms.
R ^b9 and R ^b10 may together form a ring containing a sulfur atom to which they are bonded, and the methylene group contained in the ring may be replaced by an oxygen atom, a sulfinyl group or a carbonyl group. .
R ^b11 represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 36 carbon atoms, an alicyclic hydrocarbon group having 3 to 36 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
R ^b12 represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atoms contained in the aromatic hydrocarbon group are alkoxy groups having 1 to 12 carbon atoms or 1 to 1 carbon atoms. It may be substituted with 12 alkylcarbonyloxy groups.
R ^b11 and R ^b12 may together form a ring containing —CH—CO— to which they are bonded, and the methylene group contained in the ring is an oxygen atom, a sulfinyl group or a carbonyl group. May be replaced.

R ^b13 to R ^b18 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an alkoxy group having 1 to 12 carbon atoms.
L ^b31 represents a sulfur atom or an oxygen atom.
o2, p2, s2, and t2 each independently represent an integer of 0 to 5;
q2 and r2 each independently represent an integer of 0 to 4;
u2 represents 0 or 1;
When o2 is 2 or more, multiple R ^b13 are the same or different, when p2 is 2 or more, multiple R ^b14 are the same or different, and when q2 is 2 or more, multiple R ^b15 are the same or different. , when r2 is 2 or more, the plurality of R ^b16 are the same or different; when s2 is 2 or more, the plurality of R ^b17 are the same or different; when t2 is 2 or more, the plurality of R ^b18 are the same or different; different.

特に、Ｒ^b9～Ｒ^b12の脂環式炭化水素基は、好ましくは炭素数３～１８、より好ましくは炭素数４～１２である。 Examples of aliphatic hydrocarbon groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group and n-octyl. and the alkyl groups of the 2-ethylhexyl group. In particular, the aliphatic hydrocarbon groups of R ^b9 to R ^b12 preferably have 1 to 12 carbon atoms.
The alicyclic hydrocarbon group may be either monocyclic or polycyclic, and the monocyclic alicyclic hydrocarbon group includes a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclo Cycloalkyl groups such as a heptyl group, a cyclooctyl group, and a cyclodecyl group can be mentioned. The polycyclic alicyclic hydrocarbon group includes decahydronaphthyl group, adamantyl group, norbornyl group and the following groups.

In particular, the alicyclic hydrocarbon groups of R ^b9 to R ^b12 preferably have 3 to 18 carbon atoms, more preferably 4 to 12 carbon atoms.

Alicyclic hydrocarbon groups in which hydrogen atoms are substituted with aliphatic hydrocarbon groups include methylcyclohexyl group, dimethylcyclohexyl group, 2-alkyladamantan-2-yl group, methylnorbornyl group, isobornyl group and the like. are mentioned. In the alicyclic hydrocarbon group in which a hydrogen atom is substituted with an aliphatic hydrocarbon group, the total carbon number of the alicyclic hydrocarbon group and the aliphatic hydrocarbon group is preferably 20 or less.

The aromatic hydrocarbon group includes a phenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a p-ethylphenyl group, a p-tert-butylphenyl group, a p-cyclohexylphenyl group and a p-adamantylphenyl group. , biphenylyl group, naphthyl group, phenanthryl group, 2,6-diethylphenyl group and 2-methyl-6-ethylphenyl group.
When the aromatic hydrocarbon group contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms or an alicyclic hydrocarbon group having 3 to 18 carbon atoms groups are preferred.
Aromatic hydrocarbon groups in which a hydrogen atom is substituted with an alkoxy group include a p-methoxyphenyl group and the like.
Aliphatic hydrocarbon groups in which hydrogen atoms are substituted with aromatic hydrocarbon groups include aralkyl groups such as benzyl, phenethyl, phenylpropyl, trityl, naphthylmethyl and naphthylethyl groups.

Alkoxy groups include methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy, decyloxy and dodecyloxy groups.
Acyl groups include acetyl, propionyl and butyryl groups.
Halogen atoms include fluorine, chlorine, bromine and iodine atoms.
The alkylcarbonyloxy group includes a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an isopropylcarbonyloxy group, an n-butylcarbonyloxy group, a sec-butylcarbonyloxy group, a tert-butylcarbonyloxy group, pentylcarbonyloxy group, hexylcarbonyloxy group, octylcarbonyloxy group, 2-ethylhexylcarbonyloxy group and the like.

The sulfur atom-containing ring formed by R ^b4 and R ^b5 together may be a monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated ring. . This ring includes a ring having 3 to 18 carbon atoms, preferably a ring having 4 to 18 carbon atoms. Further, the ring containing a sulfur atom includes a 3- to 12-membered ring, preferably a 3- to 7-membered ring, and examples thereof include the following rings.

The ring formed by R ^b9 and R ^b10 together may be a monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated ring. This ring includes a 3- to 12-membered ring, preferably a 3- to 7-membered ring. Examples include thiolan-1-ium ring (tetrahydrothiophenium ring), thian-1-ium ring, 1,4-oxathian-4-ium ring and the like.
The ring formed by R ^b11 and R ^b12 together may be a monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated ring. This ring includes a 3- to 12-membered ring, preferably a 3- to 7-membered ring. oxocycloheptane ring, oxocyclohexane ring, oxonorbornane ring, oxoadamantane ring and the like.

Among the cations (b2-1) to (b2-4), the cation (b2-1) is preferred.

Examples of the cation (b2-1) include the following cations.

Examples of the cation (b2-2) include the following cations.

Examples of the cation (b2-3) include the following cations.

Examples of the cation (b2-4) include the following cations.

The acid generator (I) can arbitrarily combine the anions and cations described above.
The acid generator (I) includes salts listed in Table 1.
Salt (I-1) in Table 1 represents the following salts.

Among them, the acid generator (I) is a salt (I-1), a salt (I-2), a salt (I-3), a salt (I-4), a salt (I-9), a salt (I- 10), salt (I-11), salt (I-12), salt (I-17), salt (I-18), salt (I-19), salt (I-20), salt (I-25) ), salt (I-26), salt (I-27) and salt (I-28) are preferred.

で表される基を表す）及び有機カチオン（Ｚ^＋）からなる酸発生剤（Ｉ１）は、式（Ｉ１―ａ）で表される塩を、式（Ｉ１―ｂ）で表される化合物と、塩基触媒下、溶媒中で反応させることにより製造することができる。

（式中、Ｘ^a、Ｘ^b、Ｌ¹、Ｑ¹、Ｑ²、Ｗ及びＺは上記と同じ意味を表す。）
この反応における酸触媒としては、トリエチルアミン等が挙げられる。
この反応における溶媒としては、クロロホルム、アセトニトリル、ジメチルホルムアミド等が挙げられる。
反応温度は、通常、０～８０℃、反応時間は通常０．５～１２時間が挙げられる。 <Method for producing acid generator (I)>
An anion represented by formula (aa2) (where X ¹ is

The acid generator (I1) consisting of an organic cation (Z ⁺ ) and an organic cation (Z + ) converts the salt represented by the formula (I1-a) to the compound represented by the formula (I1-b) can be produced by reacting in a solvent under a base catalyst.

(Wherein, X ^a , X ^b , L ¹ , Q ¹ , Q ² , W and Z have the same meanings as above.)
Examples of acid catalysts for this reaction include triethylamine and the like.
Solvents in this reaction include chloroform, acetonitrile, dimethylformamide and the like.
The reaction temperature is usually 0 to 80° C., and the reaction time is usually 0.5 to 12 hours.

（式中、Ｘ^a、Ｘ^b、Ｌ¹、Ｑ¹、Ｑ²、Ｗ及びＺは上記と同じ意味を表す。）
この反応における酸触媒としては、ｐ－トルエンスルホン酸等が挙げられる。
この反応における溶媒としては、クロロホルム、アセトニトリル、ジメチルホルムアミド等が挙げられる。
反応温度は、通常、０～８０℃、反応時間は通常０．５～１２時間が挙げられる。
式（Ｉ１－ｃ）で表される塩は、特開２００７－２２４００８号公報、特開２０１２－２２４６１１号公報に記載された方法で合成することができ、以下で表される塩などが挙げられる。

式（Ｉ２－ｄ）で表される化合物としては、下記式で表される化合物等が挙げられ、市場より容易に入手することができる。

The salt represented by the formula (I1-a) can be obtained by reacting the salt represented by the formula (I1-c) with the compound represented by the formula (I1-d) in the presence of an acid catalyst in a solvent. can be manufactured.

(Wherein, X ^a , X ^b , L ¹ , Q ¹ , Q ² , W and Z have the same meanings as above.)
Examples of the acid catalyst for this reaction include p-toluenesulfonic acid and the like.
Solvents in this reaction include chloroform, acetonitrile, dimethylformamide and the like.
The reaction temperature is usually 0 to 80° C., and the reaction time is usually 0.5 to 12 hours.
The salt represented by the formula (I1-c) can be synthesized by the methods described in JP-A-2007-224008 and JP-A-2012-224611, and examples thereof include salts represented by the following. .

Examples of the compound represented by formula (I2-d) include compounds represented by the following formula, etc., which are readily available on the market.

<Acid generator (B)>
As the acid generator (B), a known acid generator can be used, and it may be an ionic acid generator or a nonionic acid generator. Preferably, it is an ionic acid generator. Ionic acid generators include ionic acid generators comprising a combination of known cations and known anions.

Examples of the acid generator (B) include organic sulfonic acids, organic sulfonium salts, and the like. agents and the like. Specific examples include those represented by formulas (B1-1) to (B1-48), respectively, among which formulas (B1-1) to (B1-3) containing an arylsulfonium cation, formula ( B1-5) ~ formula (B1-7), formula (B1-11) ~ formula (B1-14), formula (B1-20) ~ formula (B1-26), formula (B1-29), formula (B1 -31) to Formula (B1-40), and those represented by Formulas (B1-41) to (B1-48) are particularly preferred.

The acid generator (B) may contain one kind alone, or may contain two or more kinds.
The acid generator (B) is preferably contained in an amount of 1 to 20 parts by weight, more preferably 3 to 15 parts by weight or more, per 100 parts by weight of the resin (A).
When acid generator (I) and acid generator (B) are used as acid generators in the resist composition, the content of acid generator (I) and acid generator (B) is 100% by weight of resin (A). parts by weight, preferably 1.5 to 40 parts by weight, more preferably 3 to 35 parts by weight.
In addition, when the salt having an anion represented by the formula (aa2) which does not correspond to the acid generator (I) and the above-mentioned salts (I-1) to (I-32) are used as the acid generator, the same applies as above. It is preferable to set the content of

<Solvent (E)>
The content of the solvent (E) is usually 90% by mass or more, preferably 92% by mass or more, more preferably 94% by mass or more, and 99.9% by mass or less, preferably 99% by mass or less in the resist composition. is. The content of the solvent (E) can be measured by known analytical means such as liquid chromatography or gas chromatography.

Examples of the solvent (E) include glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate; glycol ethers such as propylene glycol monomethyl ether; ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; One type of solvent (E) may be contained alone, or two or more types may be contained.
The solvent (E) preferably contains γ-butyrolactone in terms of solubility of the acid generator. If a large amount of γ-butyrolactone is contained, the top of the resist pattern tends to be rounded.
That is, the proportion of γ-butyrolactone in the total solvent is preferably 0.1% by weight or more and 5% by weight or less, more preferably 0.2% by weight or more and 3% by weight or less. More preferably, it is 3% by weight or more and 1.5% by weight or less.
In addition to γ-butyrolactone, it is preferable that at least one solvent selected from propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether and ketone solvents is included as a solvent, and propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether and ketone solvents are included. It preferably contains a solvent.
As the ketone solvent, 2-heptanone and cyclohexanone are preferred, and 2-heptanone is more preferred.

<Quencher (C)>
The resist composition of the present invention may contain a quencher (hereinafter sometimes referred to as "quencher (C)"). The quencher (C) includes a basic nitrogen-containing organic compound or a salt that generates a weaker acid than the acid generator (B).

<Basic nitrogen-containing organic compound>
Basic nitrogen-containing organic compounds include amines and ammonium salts. Amines include aliphatic amines and aromatic amines. Aliphatic amines include primary, secondary and tertiary amines.

Specifically, 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N,N-dimethylaniline, diphenylamine, hexylamine , heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine , ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris[2-(2-methoxyethoxy)ethyl]amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4'-diamino-1,2-diphenylethane, 4,4'-diamino-3,3'-dimethyldiphenylmethane, 4,4'-diamino- 3,3′-diethyldiphenylmethane, 2,2′-methylenebisaniline, imidazole, 4-methylimidazole, pyridine, 4-methylpyridine, 1,2-di(2-pyridyl)ethane, 1,2-di(4 -pyridyl)ethane, 1,2-di(2-pyridyl)ethene, 1,2-di(4-pyridyl)ethene, 1,3-di(4-pyridyl)propane, 1,2-di(4-pyridyl) oxy)ethane, di(2-pyridyl)ketone, 4,4'-dipyridylsulfide, 4,4'-dipyridyldisulfide, 2,2'-dipyridylamine, 2,2'-dipicolylamine, bipyridine and the like. , preferably diisopropylaniline, and particularly preferably 2,6-diisopropylaniline.

Ammonium salts include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, 3-(trifluoromethyl)phenyltrimethyl ammonium hydroxide, tetra-n-butylammonium salicylate and choline;

<Salts that generate weakly acidic acids>
The acidity of a salt that generates an acid that is weaker than the acid generated from the acid generator is indicated by the acid dissociation constant (pKa). The salt that generates an acid weaker in acidity than the acid generated from the acid generator is a salt with a pKa of -3<pKa, preferably -1<pKa<7. and more preferably a salt with 0<pKa<5. Salts that generate an acid weaker than the acid generated from the acid generator include salts represented by the following formula, weak acid inner salts represented by formula (D) described in JP-A-2015-147926, and particularly Examples include salts described in JP-A-2012-229206, JP-A-2012-6908, JP-A-2012-72109, JP-A-2011-39502 and JP-A-2011-191745.
When the resist composition of the present invention contains a plurality of types of acid generators, the salt that generates a weakly acidic acid generates an acid that is weaker than the acids generated from all of the acid generators. It is preferably a salt that

［式（Ｄ）中、
Ｒ^D1及びＲ^D2は、それぞれ独立に、炭素数１～１２の１価の炭化水素基、炭素数１～６のアルコキシ基、炭素数２～７のアシル基、炭素数２～７のアシルオキシ基、炭素数２～７のアルコキシカルボニル基、ニトロ基又はハロゲン原子を表す。
ｍ’及びｎ’は、それぞれ独立に、０～４のいずれかの整数を表し、ｍ’が２以上の場合、複数のＲ^D1は同一であっても異なってもよく、ｎ’が２以上の場合、複数のＲ^D2は同一であっても異なってもよい。］

[In the formula (D),
R ^D1 and R ^D2 are each independently a monovalent hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 7 carbon atoms, and an acyloxy group having 2 to 7 carbon atoms. , represents an alkoxycarbonyl group having 2 to 7 carbon atoms, a nitro group or a halogen atom.
m' and n' each independently represent an integer of 0 to 4, and when m' is 2 or more, the plurality of R ^D1 may be the same or different, and n' is 2 or more , the plurality of R ^D2 may be the same or different. ]

Examples of hydrocarbon groups for R ^D1 and R ^D2 include aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, groups formed by combining these groups, and the like.
The aliphatic hydrocarbon group includes alkyl groups such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, pentyl group, hexyl group and nonyl group.
The alicyclic hydrocarbon group may be monocyclic or polycyclic, and may be saturated or unsaturated. cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclononyl group and cyclododecyl group; norbornyl group; adamantyl group;
Aromatic hydrocarbon groups include phenyl group, 1-naphthyl group, 2-naphthyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 4-ethylphenyl group and 4-propylphenyl group. , 4-isopropylphenyl group, 4-butylphenyl group, 4-t-butylphenyl group, 4-hexylphenyl group, 4-cyclohexylphenyl group, anthryl group, p-adamantylphenyl group, tolyl group, xylyl group, cumenyl group , a mesityl group, a biphenyl group, a phenanthryl group, a 2,6-diethylphenyl group, and an aryl group such as 2-methyl-6-ethylphenyl.
Groups formed by combining these include alkyl-cycloalkyl groups, cycloalkyl-alkyl groups, aralkyl groups (e.g., phenylmethyl group, 1-phenylethyl group, 2-phenylethyl group, 1-phenyl-1 -propyl group, 1-phenyl-2-propyl group, 2-phenyl-2-propyl group, 3-phenyl-1-propyl group, 4-phenyl-1-butyl group, 5-phenyl-1-pentyl group, 6 -phenyl-1-hexyl group, etc.).

The alkoxy group includes a methoxy group, an ethoxy group, and the like.
The acyl group includes acetyl group, propanoyl group, benzoyl group, cyclohexanecarbonyl group and the like.
Examples of the acyloxy group include groups in which an oxy group (--O--) is bonded to the above acyl group.
Examples of the alkoxycarbonyl group include groups in which a carbonyl group (--CO--) is bonded to the above alkoxy group.
A fluorine atom, a chlorine atom, a bromine atom etc. are mentioned as a halogen atom.

R ^D1 and R ^D2 each independently represent an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an acyl group having 2 to 4 carbon atoms, and an acyl group having 2 to 4 carbon atoms. Acyloxy groups having 2 to 4 carbon atoms, alkoxycarbonyl groups having 2 to 4 carbon atoms, nitro groups or halogen atoms are preferred.
Each of m' and n' is preferably an integer of 0 to 2, more preferably 0. When m' is 2 or more, multiple R ^D1 may be the same or different, and when n' is 2 or more, multiple R ^D2 may be the same or different.

The content of the quencher (C) in the solid content of the resist composition is preferably 0.01 to 5% by mass, more preferably 0.01 to 4% by mass, and particularly preferably 0.01 to 3%. % by mass.

<Other ingredients>
If necessary, the resist composition of the present invention may contain components other than the components described above (hereinafter sometimes referred to as "other components (F)"). Other components (F) are not particularly limited, and additives known in the field of resists, such as sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes, etc., can be used.

<Preparation of resist composition>
The resist composition of the present invention comprises the resin (A) and acid generator (I) of the present invention, and, if necessary, resin (X), acid generator (B), quencher (C), solvent ( It can be prepared by mixing E) and other components (F). The mixing order is arbitrary and not particularly limited. The temperature during mixing can be appropriately selected from 10 to 40° C. depending on the type of resin or the like and the solubility of the resin or the like in the solvent (E). An appropriate mixing time can be selected from 0.5 to 24 hours depending on the mixing temperature. The mixing means is also not particularly limited, and stirring and mixing can be used.
After mixing each component, it is preferable to filter using a filter having a pore size of about 0.003 to 0.2 μm.

<Method for producing resist pattern>
The method for producing a resist pattern of the present invention comprises:
(1) a step of applying a resist composition onto a substrate;
(2) a step of drying the coated resist composition to form a composition layer;
(3) exposing the composition layer;
(4) a step of heating the exposed composition layer; and (5) a step of developing the heated composition layer with a developer containing butyl acetate.

In step (1), the substrate is not particularly limited, and substrates commonly used in the manufacture of semiconductors, for example, inorganic substrates such as silicon, SiN, SiO ₂ and SiN, coated inorganic substrates such as SOG, etc., can be mentioned. be able to. These substrates may be washed or may be inorganic substrates on which an antireflection film or the like is formed. The antireflection coating can be formed, for example, from a commercially available organic antireflection coating composition.
The coating of the resist composition on the substrate can be carried out using a commonly used device such as a spin coater.

In the step (2), for example, a heating means (so-called pre-baking) using a heating device such as a hot plate, or a decompression means using a decompression device, or a combination of these means, the resist composition coated on the substrate. Drying the material removes the solvent to form a composition layer. Drying by heating means is preferred. The conditions of the heating means and pressure reducing means can be selected according to the type of the solvent (D) contained in the resist composition.
In the case of heating means, the drying temperature is preferably 50 to 200°C, more preferably 60 to 150°C. Also, the drying time is preferably 10 to 180 seconds, more preferably 30 to 120 seconds.
In the case of decompression means, the resist composition coated on the substrate is placed in a decompression dryer and then dried at an internal pressure of 1 to 1.0×10 ⁵ Pa.
The film thickness of the composition layer thus formed is, for example, 20 to 1000 nm, preferably 50 to 400 nm. The film thickness can be adjusted by variously adjusting the conditions of the coating apparatus.

In step (3), the composition layer is preferably exposed using an exposure machine. The exposure machine may be an immersion exposure machine. At this time, exposure is performed through a mask corresponding to the desired pattern. As the exposure light source, a KrF excimer laser (wavelength: 248 nm), an ArF excimer laser (wavelength: 193 nm), an F2 excimer laser ₍ wavelength: 157 nm) that emits a laser beam in the ultraviolet region, a solid-state laser source (YAG or semiconductor laser etc.) and emits harmonic laser light in the far ultraviolet region or vacuum ultraviolet region by wavelength conversion, electron beam, and extreme ultraviolet light (EUV). can be done. When an electron beam is used as the exposure light source, the composition layer may be directly irradiated and drawn without using a mask. An ArF excimer laser is preferable as the exposure light source used in the manufacturing method of the present invention.

The exposure is preferably carried out by a method in which an immersion medium is placed on the composition layer, that is, so-called immersion exposure. When performing immersion exposure, a step of washing the surface of the composition layer before and/or after exposure with a water-based chemical solution may be performed.
The immersion medium used for immersion lithography is transparent to the exposure wavelength of the ArF excimer laser and has a temperature coefficient of refractive index that minimizes distortion of the optical image projected onto the composition layer. A liquid as small as possible is preferable, and water, particularly ultrapure water, is preferable because of its availability and ease of handling. When water is used as the immersion medium, an additive that reduces the surface tension of water and increases the surface activity may be added to the water in a small proportion. Preferably, the additive does not dissolve the composition layer and has negligible effect on the optical coating on the bottom surface of the lens element.
The exposure dose can be appropriately set according to the resist composition used, the type of resist pattern to be produced and the type of exposure light source, and is preferably 5 to 50 mJ/cm ² .
Step (3) may be repeated multiple times. The exposure light source and the exposure method for multiple exposures may be the same or different.

The heating (so-called post-exposure bake) in step (4) is performed using a heating device such as a hot plate. The heating temperature is preferably 50 to 200°C, more preferably 70 to 150°C. Also, the heating time is preferably 10 to 180 seconds, more preferably 30 to 120 seconds.

Step (5) is preferably developed with a developer using a developing device.

The developer used in step (5) contains butyl acetate.
The developer may contain a solvent other than butyl acetate. Examples of such solvents include ketone solvents such as 2-heptanone and 2-hexanone; ester solvents such as propylene glycol monomethyl ether acetate; alcohol solvents such as propylene glycol monomethyl ether; and amide solvents such as N,N-dimethylacetamide. ; it may contain a polar solvent such as an ether solvent such as glycol ether, or a hydrocarbon solvent such as anisole. It may contain a small amount of water.
The content of butyl acetate is preferably 50% by mass or more with respect to the total amount of the developer, and more preferably substantially only butyl acetate. As these developers, commercially available solvents may be used as they are.

The developer may contain a surfactant, if necessary. The surfactant is not particularly limited, but may be, for example, an ionic surfactant or a nonionic surfactant, a fluorine-based surfactant, a silicon-based surfactant, or the like.

As the development method, the composition layer subjected to the step (4) is immersed together with the substrate for a certain period of time in a tank filled with a developer (dip method). A method of developing by raising the developer by surface tension and standing still for a certain period of time (puddle method), a method of spraying the developer onto the surface of the composition layer after step (4) (spray method), and after step (4). A method (dynamic dispensing method), in which the substrate on which the composition layer is formed is rotated at a constant speed and the developer is continuously applied while scanning the application nozzle at a constant speed, can be used.
Among them, the development method is preferably a paddle method or a dynamic dispense method, more preferably a dynamic dispense method.
The developing temperature is preferably 5 to 60°C, more preferably 10 to 40°C. The development time is preferably 5 to 300 seconds, more preferably 5 to 90 seconds. When the development is performed by the dynamic dispensing method, the development time is particularly preferably 5 to 30 seconds, and when the development is performed by the puddle method, the development time is particularly preferably 20 to 60 seconds.

It is preferable to wash the resist pattern after development with a rinsing liquid. The rinse liquid is not particularly limited as long as it does not dissolve the resist pattern, and a solution containing a general organic solvent can be used, preferably an alcohol solvent or an ester solvent.
After cleaning, it is preferable to remove the rinse liquid remaining on the substrate and pattern.

<Application>
The method for producing a resist pattern of the present invention includes a method for producing a resist pattern by KrF excimer laser exposure, ArF excimer laser exposure, electron beam (EB) exposure or EUV exposure, and a method for producing a resist pattern by liquid immersion exposure. It is suitable as a method for producing a resist pattern for immersion ArF excimer laser exposure, and is useful for microfabrication of semiconductors.

EXAMPLES The present invention will be described in detail below with reference to examples.
In the examples and comparative examples, "%" and "parts" representing contents and usage amounts are based on mass unless otherwise specified.
The weight average molecular weight is a value obtained by gel permeation chromatography under the following conditions.
Apparatus: HLC-8120GPC type (manufactured by Tosoh Corporation)
Column: TSKgel Multipore H _XL -M x 3 + guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL/min
Detector: RI detector Column temperature: 40°C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)

The structure of the compound was confirmed by measuring the molecular ion peak using mass spectrometry (LC: Agilent Model 1100, MASS: Agilent Model LC/MSD). In the examples below, the value of this molecular peak is indicated by "MASS".

式（Ｉ－１－ａ）で表される塩を、特開２００７－２２４００８号公報に記載された方法で合成した。
式（Ｉ－１－ａ）で表される塩７．００部、式（Ｉ－１－ｂ）で表される化合物６．５０部、クロロホルム３５部、アセトニトリル１４部及びジメチルホルムアミド１４部を仕込み、２３℃で３０分間攪拌した。その後、ｐ－トルエンスルホン酸０．０７部を添加し、３時間還流攪拌した。得られた反応物を２３℃まで冷却し、クロロホルム１５５部を添加撹拌後、ろ過した。回収されたろ液に、５％炭酸水素ナトリウム水溶液４０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液した。回収された有機層に、イオン交換水４５部を仕込み２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を３回行った。得られた有機層に酢酸エチル９５部を加えて攪拌した後、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ－１－ｃ）で表される塩４．３８部を得た。

式（Ｉ－１－ｃ）で表される塩２．５０部、クロロホルム２５部及びジメチルホルムアミド２．５部を仕込み、２３℃で３０分間攪拌した後、５℃まで冷却した。得られた混合溶液に、式（Ｉ－１－ｄ）で表される化合物０．４２部を１５分かけて添加し、さらに、トリエチルアミン０．４０部を添加した後、２３℃まで昇温し、２３℃で２時間攪拌した。得られた反応物に、イオン交換水１５部を添加撹拌し、静置し、分液した。この水洗の操作を２回行った。得られた有機層を濃縮し、得られた残渣に、アセトニトリル１．０８部及びｔｅｒｔ－ブチルメチルエーテル３２．１８部を加えて２３℃で３０分間攪拌し、上澄み液を除去し、濃縮することにより、式（Ｉ－１）で表される塩３．５８部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＡＳＳ（ＥＳＩ（－）Ｓｐｅｃｔｒｕｍ）：Ｍ^－ ４８７．１ Example 1: Synthesis of salt represented by formula (I-1)

A salt represented by formula (I-1-a) was synthesized by the method described in JP-A-2007-224008.
7.00 parts of the salt represented by the formula (I-1-a), 6.50 parts of the compound represented by the formula (I-1-b), 35 parts of chloroform, 14 parts of acetonitrile and 14 parts of dimethylformamide were charged. at 23° C. for 30 minutes. After that, 0.07 part of p-toluenesulfonic acid was added, and the mixture was stirred under reflux for 3 hours. The obtained reactant was cooled to 23° C., 155 parts of chloroform was added, and the mixture was filtered after stirring. 40 parts of a 5% sodium hydrogen carbonate aqueous solution was added to the collected filtrate, and the mixture was stirred at 23° C. for 30 minutes. After that, it was allowed to stand and liquid-separated. 45 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23° C. for 30 minutes to separate the layers, thereby recovering the organic layer. This washing operation was performed three times. After adding 95 parts of ethyl acetate to the obtained organic layer and stirring, the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 4.38 parts of the salt represented by the formula (I-1-c).

2.50 parts of the salt represented by the formula (I-1-c), 25 parts of chloroform and 2.5 parts of dimethylformamide were charged, stirred at 23°C for 30 minutes, and then cooled to 5°C. To the resulting mixed solution, 0.42 parts of the compound represented by formula (I-1-d) was added over 15 minutes, and 0.40 parts of triethylamine was further added, followed by raising the temperature to 23°C. , and stirred at 23° C. for 2 hours. 15 parts of ion-exchanged water was added to the resulting reactant, stirred, allowed to stand, and separated. This washing operation was performed twice. Concentrate the obtained organic layer, add 1.08 parts of acetonitrile and 32.18 parts of tert-butyl methyl ether to the obtained residue, stir at 23 ° C. for 30 minutes, remove the supernatant, and concentrate. to obtain 3.58 parts of the salt represented by the formula (I-1).
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 487.1

式（Ｉ－１７－ａ）で表される塩を、特開２０１２－２２４６１１号公報に記載された方法で合成した。
式（Ｉ－１７－ａ）で表される塩６．６９部、式（Ｉ－１－ｂ）で表される化合物６．５０部、クロロホルム３５部、アセトニトリル１４部及びジメチルホルムアミド１４部を混合し、２３℃で３０分間攪拌した。得られた混合物に、ｐ－トルエンスルホン酸０．０７部を添加し、３時間還流攪拌した。得られた反応物を２３℃まで冷却し、クロロホルム１５５部を添加撹拌後、ろ過した。回収されたろ液に、５％炭酸水素ナトリウム水溶液４０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液した。回収された有機層に、イオン交換水４５部を仕込み２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を３回行った。得られた有機層に酢酸エチル９５部を加えて攪拌し、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ－１７－ｃ）で表される塩３．６９部を得た。

式（Ｉ－１７－ｃ）で表される塩２．４１部、クロロホルム２５部及びジメチルホルムアミド２．５部を混合し、２３℃で３０分間攪拌し、５℃まで冷却した。得られた混合溶液に、式（Ｉ－１－ｄ）で表される化合物０．４２部を１５分かけて添加し、さらに、トリエチルアミン０．４０部を添加した。得られた混合物を２３℃まで昇温し、２３℃で２時間攪拌した。得られた反応物に、イオン交換水１５部を添加撹拌し、静置し、分液した。この水洗の操作を２回行った。得られた有機層を濃縮し、得られた残渣に、アセトニトリル１．０８部及びｔｅｒｔ－ブチルメチルエーテル３２．１８部を加えて２３℃で３０分間攪拌した。上澄み液を除去し、濃縮することにより、式（Ｉ－１７）で表される塩２．６８部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２３７．１
ＭＡＳＳ（ＥＳＩ（－）Ｓｐｅｃｔｒｕｍ）：Ｍ^－ ４８７．１ Example 2: Synthesis of salt represented by formula (I-17)

A salt represented by formula (I-17-a) was synthesized by the method described in JP-A-2012-224611.
Mix 6.69 parts of the salt represented by the formula (I-17-a), 6.50 parts of the compound represented by the formula (I-1-b), 35 parts of chloroform, 14 parts of acetonitrile and 14 parts of dimethylformamide and stirred at 23° C. for 30 minutes. 0.07 part of p-toluenesulfonic acid was added to the resulting mixture, and the mixture was stirred under reflux for 3 hours. The obtained reactant was cooled to 23° C., 155 parts of chloroform was added, and the mixture was filtered after stirring. 40 parts of a 5% sodium hydrogen carbonate aqueous solution was added to the collected filtrate, and the mixture was stirred at 23° C. for 30 minutes. After that, it was allowed to stand and liquid-separated. 45 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23° C. for 30 minutes to separate the layers, thereby recovering the organic layer. This washing operation was performed three times. 95 parts of ethyl acetate was added to the obtained organic layer and stirred, and the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 3.69 parts of the salt represented by the formula (I-17-c).

2.41 parts of the salt represented by the formula (I-17-c), 25 parts of chloroform and 2.5 parts of dimethylformamide were mixed, stirred at 23°C for 30 minutes, and cooled to 5°C. To the obtained mixed solution, 0.42 part of the compound represented by formula (I-1-d) was added over 15 minutes, and 0.40 part of triethylamine was further added. The resulting mixture was warmed to 23° C. and stirred at 23° C. for 2 hours. 15 parts of ion-exchanged water was added to the resulting reactant, stirred, allowed to stand, and separated. This washing operation was performed twice. The obtained organic layer was concentrated, 1.08 parts of acetonitrile and 32.18 parts of tert-butyl methyl ether were added to the obtained residue, and the mixture was stirred at 23° C. for 30 minutes. By removing the supernatant and concentrating, 2.68 parts of the salt represented by the formula (I-17) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 487.1

式（Ｉ－２－ａ）で表される塩を、特開２００９－４６４７９号公報に記載された方法で合成した。
式（Ｉ－２－ａ）で表される塩７．１７部、式（Ｉ－１－ｂ）で表される化合物６．５０部、クロロホルム３５部、アセトニトリル１４部及びジメチルホルムアミド１４部を混合し、２３℃で３０分間攪拌した。得られた混合物に、ｐ－トルエンスルホン酸０．０７部を添加し、３時間還流攪拌した。得られた反応物を２３℃まで冷却し、クロロホルム１５５部を添加撹拌後、ろ過した。回収されたろ液に、５％炭酸水素ナトリウム水溶液４０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液した。回収された有機層に、イオン交換水４５部を仕込み２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を３回行った。得られた有機層に酢酸エチル５０部を加えて攪拌し、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ－２－ｃ）で表される塩４．２２部を得た。

式（Ｉ－２－ｃ）で表される塩２．５５部、クロロホルム２５部及びジメチルホルムアミド２．５部を混合し、２３℃で３０分間攪拌し、５℃まで冷却した。得られた混合溶液に、式（Ｉ－１－ｄ）で表される化合物０．４２部を１５分かけて添加し、さらに、トリエチルアミン０．４０部を添加した。得られた混合物を２３℃まで昇温し、２３℃で２時間攪拌した。得られた反応物に、イオン交換水１５部を添加撹拌し、静置し、分液した。この水洗の操作を２回行った。得られた有機層を濃縮し、得られた残渣に、アセトニトリル１．０８部及びｔｅｒｔ－ブチルメチルエーテル３２．１８部を加えて２３℃で３０分間攪拌した。上澄み液を除去し、濃縮することにより、式（Ｉ－２）で表される塩３．１２部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６３．１
ＭＡＳＳ（ＥＳＩ（－）Ｓｐｅｃｔｒｕｍ）：Ｍ^－ ５０１．１ Example 3: Synthesis of salt represented by formula (I-2)

A salt represented by formula (I-2-a) was synthesized by the method described in JP-A-2009-46479.
7.17 parts of the salt represented by the formula (I-2-a), 6.50 parts of the compound represented by the formula (I-1-b), 35 parts of chloroform, 14 parts of acetonitrile and 14 parts of dimethylformamide are mixed. and stirred at 23° C. for 30 minutes. 0.07 part of p-toluenesulfonic acid was added to the resulting mixture, and the mixture was stirred under reflux for 3 hours. The obtained reactant was cooled to 23° C., 155 parts of chloroform was added, and the mixture was filtered after stirring. 40 parts of a 5% sodium hydrogen carbonate aqueous solution was added to the collected filtrate, and the mixture was stirred at 23° C. for 30 minutes. After that, it was allowed to stand and liquid-separated. 45 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23° C. for 30 minutes to separate the layers, thereby recovering the organic layer. This washing operation was performed three times. 50 parts of ethyl acetate was added to the obtained organic layer and stirred, and the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 4.22 parts of the salt represented by the formula (I-2-c).

2.55 parts of the salt represented by the formula (I-2-c), 25 parts of chloroform and 2.5 parts of dimethylformamide were mixed, stirred at 23°C for 30 minutes, and cooled to 5°C. To the obtained mixed solution, 0.42 part of the compound represented by formula (I-1-d) was added over 15 minutes, and 0.40 part of triethylamine was further added. The resulting mixture was warmed to 23° C. and stirred at 23° C. for 2 hours. 15 parts of ion-exchanged water was added to the resulting reactant, stirred, allowed to stand, and separated. This washing operation was performed twice. The obtained organic layer was concentrated, 1.08 parts of acetonitrile and 32.18 parts of tert-butyl methyl ether were added to the obtained residue, and the mixture was stirred at 23° C. for 30 minutes. By removing the supernatant and concentrating, 3.12 parts of the salt represented by the formula (I-2) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 263.1
MASS (ESI (-) Spectrum): M ^- 501.1

式（Ｉ－１８－ａ）で表される塩を、特開２０１６－１１３４５０号公報に記載された方法で合成した。
式（Ｉ－１８－ａ）で表される塩６．８６部、式（Ｉ－１－ｂ）で表される化合物６．５０部、クロロホルム３５部、アセトニトリル１４部及びジメチルホルムアミド１４部を混合し、２３℃で３０分間攪拌した。得られた混合物に、ｐ－トルエンスルホン酸０．０７部を添加し、３時間還流攪拌した。得られた反応物を２３℃まで冷却し、クロロホルム１５５部を添加撹拌後、ろ過した。回収されたろ液に、５％炭酸水素ナトリウム水溶液４０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液した。回収された有機層に、イオン交換水４５部を仕込み２３℃で３０分間攪拌し、分液することにより有機層を回収した。この水洗の操作を３回行った。得られた有機層に酢酸エチル９５部を加えて攪拌し、上澄液を除去した。得られた残渣をアセトニトリルに溶解し、濃縮することにより、式（Ｉ－１８－ｃ）で表される塩３．５５部を得た。

式（Ｉ－１８－ｃ）で表される塩２．４６部、クロロホルム２５部及びジメチルホルムアミド２．５部を混合し、２３℃で３０分間攪拌し、５℃まで冷却した。得られた混合溶液に、式（Ｉ－１－ｄ）で表される化合物０．４２部を１５分かけて添加し、さらに、トリエチルアミン０．４０部を添加した。得られた混合物を２３℃まで昇温し、２３℃で２時間攪拌した。得られた反応物に、イオン交換水１５部を添加撹拌し、静置し、分液した。この水洗の操作を２回行った。得られた有機層を濃縮し、得られた残渣に、アセトニトリル１．０８部及びｔｅｒｔ－ブチルメチルエーテル３２．１８部を加えて２３℃で３０分間攪拌した。上澄み液を除去し、濃縮することにより、式（Ｉ－１８）で表される塩２．２８部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２３７．１
ＭＡＳＳ（ＥＳＩ（－）Ｓｐｅｃｔｒｕｍ）：Ｍ^－ ５０１．１ Example 4: Synthesis of salt represented by formula (I-18)

A salt represented by formula (I-18-a) was synthesized by the method described in JP-A-2016-113450.
6.86 parts of the salt represented by the formula (I-18-a), 6.50 parts of the compound represented by the formula (I-1-b), 35 parts of chloroform, 14 parts of acetonitrile and 14 parts of dimethylformamide are mixed. and stirred at 23° C. for 30 minutes. 0.07 part of p-toluenesulfonic acid was added to the resulting mixture, and the mixture was stirred under reflux for 3 hours. The obtained reactant was cooled to 23° C., 155 parts of chloroform was added, and the mixture was filtered after stirring. 40 parts of a 5% sodium hydrogen carbonate aqueous solution was added to the collected filtrate, and the mixture was stirred at 23° C. for 30 minutes. After that, it was allowed to stand and liquid-separated. 45 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23° C. for 30 minutes to separate the layers, thereby recovering the organic layer. This washing operation was performed three times. 95 parts of ethyl acetate was added to the obtained organic layer and stirred, and the supernatant was removed. The obtained residue was dissolved in acetonitrile and concentrated to obtain 3.55 parts of the salt represented by the formula (I-18-c).

2.46 parts of the salt represented by the formula (I-18-c), 25 parts of chloroform and 2.5 parts of dimethylformamide were mixed, stirred at 23°C for 30 minutes, and cooled to 5°C. To the obtained mixed solution, 0.42 part of the compound represented by formula (I-1-d) was added over 15 minutes, and 0.40 part of triethylamine was further added. The resulting mixture was warmed to 23° C. and stirred at 23° C. for 2 hours. 15 parts of ion-exchanged water was added to the resulting reactant, stirred, allowed to stand, and separated. This washing operation was performed twice. The obtained organic layer was concentrated, 1.08 parts of acetonitrile and 32.18 parts of tert-butyl methyl ether were added to the obtained residue, and the mixture was stirred at 23° C. for 30 minutes. By removing the supernatant and concentrating, 2.28 parts of the salt represented by the formula (I-18) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 237.1
MASS (ESI (-) Spectrum): M ^- 501.1

Synthesis of Resin (A) Compounds (monomers) used for synthesis of resin (A) are shown below. Hereinafter, these compounds are referred to as "monomer (a1-1-3)" and the like according to their formula numbers.

Synthesis Example 1 [Synthesis of resin A1]
As monomers, monomer (a1-1-3), monomer (a1-2-9), monomer (a2-1-1) and monomer (a3-4-2) are used, and the molar ratio [monomer (a1-1 -3): Monomer (a1-2-9): Monomer (a2-1-1): Monomer (a3-4-2)] is mixed so that the ratio is 45:14:2.5:38.5, Propylene glycol monomethyl ether acetate was added in an amount 1.5 times the mass of the total amount of monomers to form a solution. To this solution, 1 mol % and 3 mol % of azobisisobutyronitrile and azobis(2,4-dimethylvaleronitrile) were added as initiators to the total amount of monomers, respectively, and these were heated at 75° C. for about 5 hours. did. The resulting reaction mixture was poured into a large amount of methanol/water mixed solvent to precipitate the resin, which was filtered. The resulting resin is again dissolved in propylene glycol monomethyl ether acetate, the resulting solution is poured into a methanol/water mixed solvent to precipitate the resin, and the resin is filtered. Resin A1 with a molecular weight of 7.8×10 ³ was obtained with a yield of 66%. This resin A1 has the following structural units.

Synthesis Example 2 [Synthesis of Resin X1]
Monomer (a5-1-1) and monomer (a4-0-12) are used as monomers, and the molar ratio [monomer (a5-1-1):monomer (a4-0-12)] is 50:50. and methyl isobutyl ketone was added in an amount of 1.2 times the mass of the total amount of monomers to form a solution. To this solution, 3 mol % of azobis(2,4-dimethylvaleronitrile) was added as an initiator with respect to the total amount of monomers, and the mixture was heated at 70° C. for about 5 hours. The resulting reaction mixture is poured into a large amount of methanol/water mixed solvent to precipitate the resin, and the resin is filtered to obtain resin X1 (copolymer) having a weight average molecular weight of 1.0×10 ⁴ with a yield of 91%. I got it with This resin X1 has the following structural units.

(Preparation of resist composition)
Each of the components shown below was mixed in parts by weight shown in Table 2, dissolved in a solvent, and then filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.
The prepared resist composition was divided into two, one of which was stored for 2 weeks while changing the temperature between 40° C. and −5° C. by one day.

各酸発生剤から発生する酸のハンセン溶解度パラメータにおける、分散項、極性項および水素結合項、モル体積を表３に示す。分散項、極性項及び水素結合項は、ＨＳＰｉＰバージョン４．１を用いて、推算値を用いることにより求めた。モル体積は、Ｃｈｅｍ Ｄｒａｗ Ｕｌｔｒａ Ｖｅｒ１１．０ Ｃｌｉｎｉｃａｌ Ｖｏｌ．により算出した。Ｒは、これらの値から、式（１）に基づいて算出した。分散項、極性項および水素結合項の単位は［（ＭＰａ）^１／２］、モル体積の単位は、［ｃｍ^３／ｍｏｌ］である。 <Resin>
A1, X1: Resin A1, Resin X1
<Acid Generator (I)>
I-1: salt represented by formula (I-1) I-2: salt represented by formula (I-2) I-17: salt represented by formula (I-17) I-18: formula Salt represented by (I-18) <acid generator>
B1-2: a salt represented by the formula (B1-2) (synthesized according to the examples of JP-A-2006-257078)
B1-6: a salt represented by the formula (B1-6) (synthesized according to the examples of JP-A-2007-224008)
B1-25: a salt represented by the formula (B1-25) (synthesized according to the examples of JP-A-2013-41257)
B1-31: a salt represented by the formula (B1-31) (synthesized according to the examples of JP-A-2012-97074)

Table 3 shows the dispersion term, the polarity term, the hydrogen bond term, and the molar volume in the Hansen solubility parameter of the acid generated from each acid generator. Dispersion terms, polar terms and hydrogen bonding terms were obtained by using estimated values using HSPiP version 4.1. The molar volume is determined according to Chem Draw Ultra Ver11.0 Clinical Vol. Calculated by R was calculated based on the formula (1) from these values. The unit of dispersion term, polar term and hydrogen bonding term is [(MPa) ^1/2 ], and the unit of molar volume is [cm ³ /mol].

＜溶剤-1＞
プロピレングリコールモノメチルエーテルアセテート ２６５部
プロピレングリコールモノメチルエーテル ２０部
２－ヘプタノン ２０部
γ－ブチロラクトン ３．５部
＜溶剤-2＞
プロピレングリコールモノメチルエーテルアセテート ２６５部
プロピレングリコールモノメチルエーテル ２０部
２－ヘプタノン ２０部
γ－ブチロラクトン ２部
＜溶剤-3＞
プロピレングリコールモノメチルエーテルアセテート ２６５部
プロピレングリコールモノメチルエーテル ２０部
２－ヘプタノン ２０部
γ－ブチロラクトン １部
＜溶剤-4＞
プロピレングリコールモノメチルエーテルアセテート ２６５部
プロピレングリコールモノメチルエーテル ２０部
２－ヘプタノン ２０部
γ－ブチロラクトン ９部 <Compound (D)>
D1: (manufactured by Tokyo Chemical Industry Co., Ltd.)

<Solvent-1>
Propylene glycol monomethyl ether acetate 265 parts Propylene glycol monomethyl ether 20 parts 2-heptanone 20 parts γ-butyrolactone 3.5 parts <Solvent-2>
Propylene glycol monomethyl ether acetate 265 parts Propylene glycol monomethyl ether 20 parts 2-heptanone 20 parts γ-butyrolactone 2 parts <Solvent-3>
Propylene glycol monomethyl ether acetate 265 parts Propylene glycol monomethyl ether 20 parts 2-heptanone 20 parts γ-butyrolactone 1 part <Solvent-4>
Propylene glycol monomethyl ether acetate 265 parts Propylene glycol monomethyl ether 20 parts 2-heptanone 20 parts γ-butyrolactone 9 parts

<Production of resist pattern and its evaluation>
An organic antireflection film composition [ARC-29; manufactured by Nissan Chemical Industries, Ltd.] was applied onto a 12-inch silicon wafer and baked at 205° C. for 60 seconds to form an organic film having a thickness of 78 nm. An antireflection film was formed. Next, the resist composition was spin-coated on the organic antireflection film so that the film thickness of the composition layer after drying (pre-baking) was 100 nm. After coating, the silicon wafer was pre-baked on a direct hot plate at the temperature indicated in the "PB" column of Table 2 for 60 seconds to form a composition layer on the silicon wafer.
An ArF excimer laser stepper for immersion exposure [XT: 1900Gi; manufactured by ASML, NA = 1.35, Annular σ _out = 0.85 σ _in = 0.65 XY- pol. Illumination], using a mask for forming a trench pattern (pitch: 120 nm/trench width: 40 nm), exposure was performed by changing the exposure dose stepwise. Ultrapure water was used as the liquid immersion medium.
After the exposure, post-exposure baking was performed for 60 seconds on a hot plate at the temperature indicated in the "PEB" column of Table 2. Next, the composition layer on the silicon wafer is developed using butyl acetate (manufactured by Tokyo Kasei Kogyo Co., Ltd.) as a developer by a dynamic dispensing method at 23° C. for 20 seconds to form a negative resist pattern. manufactured.

In the resulting resist pattern, the effective sensitivity was defined as the exposure dose at which the width of the trench pattern was 40 nm.

<Focus Margin Evaluation (DOF)>
A negative resist pattern was produced in the same manner as described above, except that exposure was performed while changing the focus stepwise in terms of effective sensitivity. In the obtained resist pattern, the DOF (nm) was defined as the focus range where the width of the trench pattern was 40 nm±5% (38 to 42 nm). Table 4 shows the results.
Moreover, for each composition, a trench pattern was produced in the same manner as described above using the resist composition after storage for 2 weeks, and the DOF was measured to obtain the DOF over time.
Those results are shown in Table 4.

The focus margin (DOF) of the resist pattern obtained from the resist composition of the present invention is good, and the performance change is not observed even with the passage of time of the resist composition, so it is suitable for fine processing of semiconductors, and is extremely industrially. Useful.

Claims (16)

A resist composition containing a resin containing a structural unit having an acid-labile group, an acid generator and a solvent,
The acid generator has an anion represented by the formula (aa2) and has a hydrogen bond term (δh) of 12 (MPa) ^1/2 or more and 15 (MPa) ^1/2 or less in the Hansen solubility parameters. is a salt that generates an acid, and
A resist composition represented by the following formula (1), which is a salt generating an acid having a solubility index (R) of 7.50 or less based on the Hansen solubility parameter for γ-butyrolactone.

[in formula (aa2),
a group represented by the formula (aa),

The portion corresponding to represents a group represented by any one of the following .

Ring W represents a ring represented by any one of the following formulas (a1-1), (a1-2) and (a1-6) .

L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, the methylene group contained in the saturated hydrocarbon group may be replaced by an oxygen atom or a carbonyl group, The contained hydrogen atoms may be substituted with fluorine atoms or hydroxy groups.
Q ¹ and Q ² independently represent a fluorine atom or a C 1-6 perfluoroalkyl group. ]
R=(4(δd-18.0) ² +(δp-16.6) ² +(δh-7.4) ² ) ^1/2
(1)
(In formula (1),
δd represents the dispersion term in the Hansen solubility parameter,
δp denotes the polar term in the Hansen solubility parameters,
δh denotes the hydrogen bonding term in the Hansen solubility parameters. ) 2. The resist composition according to claim 1, wherein the acid generator is an acid generator capable of generating an acid having a molar volume of 850 cm< ³ >/mol or more. (1) The structural unit having an acid labile group is at least one selected from the group consisting of structural units represented by formula (a1-0), formula (a1-1) and formula (a1-2). or the resist composition according to 2.

[In formula (a1-0), formula (a1-1) and formula (a1-2),
L ^a01 , L ^a1 and L ^a2 each independently represent —O— or ^* —O—(CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, * is represents a bond with -CO-.
R ^a01 , R ^a4 and R ^a5 each independently represent a hydrogen atom or a methyl group.
R ^a02 , R ^a03 and R ^a04 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a combination thereof.
R ^a6 and R ^a7 each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group formed by combining these.
m1 represents any integer from 0 to 14;
n1 represents any integer from 0 to 10;
n1' represents an integer of 0 to 3; ] 4. The resist composition according to any one of claims 1 to 3, wherein the resin further contains a structural unit having a lactone ring and no acid labile group. 5. The resist composition according to claim 4, wherein the structural unit having a lactone ring and no acid labile group is a structural unit represented by formula (a3-4).

[In formula (a3-4),
R ^a24 represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
L ^a7 is -O-, ^* -OL ^a8 -O-, ^* -OL ^a8 -CO-O-, ^* -OL ^a8 -CO-O-L ^a9 -CO-O- or ^* -O-L ^a8 -O-CO-L ^a9 -O-.
* represents a bond with -CO-.
L ^a8 and L ^a9 each independently represent an alkanediyl group having 1 to 6 carbon atoms.
R ^a25 represents a carboxy group, a cyano group or an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
w1 represents any integer from 0 to 8; When w1 is 2 or more, a plurality of R ^a25 may be the same or different. ] 6. The resist composition according to any one of claims 1 to 5, wherein the resin further contains a structural unit having a hydroxy group. 7. The resist composition according to claim 1, wherein the acid generated from the acid generator has a ring structure containing --O--SO--O-- as a ring constituent. 8. The resist composition according to any one of claims 1 to 7, wherein the solvent contains γ-butyrolactone. The proportion of γ-butyrolactone in the solvent is 0. 9. The resist composition according to claim 8, which is 1% by weight or more and 5% by weight or less. The proportion of γ-butyrolactone in the solvent is 0. 10. The resist composition according to claim 9, which is 2% by weight or more and 3% by weight or less. The proportion of γ-butyrolactone in the solvent is 0. 9. The resist composition according to claim 8, which is 3% by weight or more and 1.5% by weight or less. 12. The resist composition according to any one of claims 8 to 11, wherein the solvent further contains at least one selected from propylene glycol monomethyl ether acetate, propylene glycol monomethyl ether and ketone solvents. 13. The resist composition according to claim 12, wherein the ketone solvent is 2-heptanone. 14. The resist composition according to any one of claims 1 to 13, further comprising a resin containing a structural unit having a fluorine atom. 15. The resist composition according to any one of claims 1 to 14, further comprising a salt that generates an acid weaker in acidity than the acid generated from the acid generator. (1) a step of applying the resist composition according to any one of claims 1 to 15 onto a substrate;
(2) a step of drying the applied composition to form a composition layer;
(3) exposing the composition layer;
(4) a step of heating the composition layer after exposure; and (5) a step of developing the composition layer after heating.