JP6958071B2 - Method for Producing Acid Generator, Gist Composition and Resist Pattern - Google Patents

Description

The present invention relates to a salt used for microfabrication of a semiconductor, an acid generator containing the salt, a resist composition, and a method for producing a resist pattern.

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.

Japanese Unexamined Patent Publication No. 2008-24671 Japanese Unexamined Patent Publication No. 2006-257878

In the resist composition containing the salt represented by the above formula, the mask error factor (MEF) at the time of producing the resist pattern was not always satisfactory.

［式（Ｉ）中、
Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８、Ｒ^９、Ｒ^１０及びＲ^１１は、それぞれ独立に、水素原子、ヒドロキシ基又は炭素数１〜１２の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ₂−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
ｎは、０又は１を表す。
Ｑ¹及びＱ²は、それぞれ独立に、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。
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−ＣＨ_２−は−Ｏ−又は−ＣＯ−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。
Ｙは、メチル基又は置換基を有していてもよい炭素数３〜１８の脂環式飽和炭化水素基を表し、該脂環式飽和炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−、−ＳＯ_２−又は−ＣＯ−に置き換わっていてもよい。］
［２］ｎが、１である［１］記載の塩。
［３］Ｒ^３が、炭素数１〜８のアルキル基である［１］又は［２］記載の塩。
［４］Ｙが、置換基を有していてもよいアダマンチル基を表し、該アダマンチル基に含まれる−ＣＨ_２−は、−Ｏ−又は−ＣＯ−に置き換わっていてもよい［１］〜［３］のいずれか記載の塩。
［５］［１］〜［４］のいずれかに記載の塩と酸不安定基を有する樹脂とを含有するレジスト組成物。
［６］樹脂が、さらに、ラクトン環を有する構造単位を含む［５］に記載のレジスト組成物。
［７］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［５］又は［６］に記載のレジスト組成物。
［８］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［５］〜［７］のいずれかに記載のレジスト組成物。
［９］ （１）［５］〜［８］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 salt represented by the formula (I).

[In formula (I),
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ each independently have a hydrogen atom, a hydroxy group or 1 to 12 carbon atoms. Representing a hydrocarbon group, −CH ₂ − contained in the hydrocarbon group may be replaced with −O− or −CO−.
n represents 0 or 1.
Q ¹ and Q ² independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and -CH _2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-, and the saturated hydrocarbon may be replaced. The hydrogen atom contained in the hydrogen group may be substituted with a fluorine atom or a hydroxy group.
Y represents an alicyclic saturated hydrocarbon group having 3 to 18 carbon atoms which may have a methyl group or a substituent, and −CH ₂ − contained in the alicyclic saturated hydrocarbon group is −O. It may be replaced with −, −SO _{2− or −CO−.} ]
[2] The salt according to [1], wherein n is 1.
[3] The salt according to [1] or [2], wherein ^{R 3 is an alkyl group having 1 to 8 carbon atoms.}
[4] Y represents an adamantyl group which may have a substituent, and -CH _2- contained in the adamantyl group may be replaced with -O- or -CO- [1] to [ 3] The salt according to any one of.
[5] A resist composition containing the salt according to any one of [1] to [4] and a resin having an acid unstable group.
[6] The resist composition according to [5], wherein the resin further contains a structural unit having a lactone ring.
[7] The resist composition according to [5] or [6], which further contains a salt that generates an acid having a weaker acidity than the acid generated from the acid generator.
[8] The resist composition according to any one of [5] to [7], which further contains a resin containing a structural unit having a fluorine atom.
[9] (1) A step of applying the resist composition according to any one of [5] to [8] onto a substrate.
(2) A step of drying the applied composition to form a composition layer,
(3) Step of 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,
A method for producing a resist pattern including.

Provided are a salt capable of producing a resist pattern with a good mask error factor (MEF) and a resist composition containing the salt.

As used herein, the term "(meth) acrylic monomer" means at least one type of monomer having a structure of _{"CH 2} = CH-CO-" or "CH ₂ = C (CH _{3) -CO-".} do. 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.
In the present specification, the "solid content of the resist composition" means the total amount of the components excluding the solvent (E) described later from the total amount of the resist composition.

<Salt represented by formula (I) (hereinafter, may be referred to as salt (I))>

［式（Ｉ）中、
Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５、Ｒ^６、Ｒ^７、Ｒ^８、Ｒ^９、Ｒ^１０及びＲ^１１は、それぞれ独立に、水素原子、ヒドロキシ基又は炭素数１〜１２の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ₂−は、−Ｏ−又は−ＣＯ−で置き換わっていてもよい。
ｎは、０又は１を表す。
Ｑ¹及びＱ²は、それぞれ独立に、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。
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−ＣＨ_２−は−Ｏ−又は−ＣＯ−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。
Ｙは、メチル基又は置換基を有していてもよい炭素数３〜１８の脂環式飽和炭化水素基を表し、該脂環式飽和炭化水素基に含まれる−ＣＨ_２−は、−Ｏ−、−ＳＯ_２−又は−ＣＯ−に置き換わっていてもよい。］

[In formula (I),
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ each independently have a hydrogen atom, a hydroxy group or 1 to 12 carbon atoms. Representing a hydrocarbon group, −CH ₂ − contained in the hydrocarbon group may be replaced with −O− or −CO−.
n represents 0 or 1.
Q ¹ and Q ² independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
L ^b1 represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and -CH _2- contained in the saturated hydrocarbon group may be replaced with -O- or -CO-, and the saturated hydrocarbon may be replaced. The hydrogen atom contained in the hydrogen group may be substituted with a fluorine atom or a hydroxy group.
Y represents an alicyclic saturated hydrocarbon group having 3 to 18 carbon atoms which may have a methyl group or a substituent, and −CH ₂ − contained in the alicyclic saturated hydrocarbon group is −O. It may be replaced with −, −SO _{2− or −CO−.} ]

The hydrocarbon groups of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ having 1 to 12 carbon atoms include alkyl groups and alicyclics. Examples thereof include a type hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these groups.
Alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, 2-ethylhexyl group and octyl group. , Nonyl group, decyl group, undecyl group, dodecyl group and the like.
The alicyclic hydrocarbon group may be either a monocyclic group or a polycyclic group, and the monocyclic alicyclic hydrocarbon group includes a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group and a methylcyclohexyl group. , Cycloalkyl groups such as dimethylcyclohexyl group, cycloheptyl group, cyclooctyl group, cyclodecyl group and the like. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a 2-alkyladamantan-2-yl group, a 1- (adamantan-1-yl) alkane-1-yl group, and a norbornyl group. Examples thereof include a methylnorbornyl group and an isobornyl group.
Examples of the aromatic hydrocarbon group include a phenyl group and a naphthyl group.
Examples of the group formed by combining these include an aralkyl group, a benzyl group, a phenethyl group and the like.
As a group in which −CH ₂ − contained in the hydrocarbon group is replaced with −O− or −CO−, an alkoxy group having 1 to 12 carbon atoms such as a methoxy group, an ethoxy group, and a butoxy group; an acetyl group; a methoxycarbonyl group. Examples thereof include an alkoxycarbonyl group having 2 to 12 carbon atoms such as a group, an acetyloxy group and a butoxycarbonyloxy group; and an acyloxy group having 2 to 12 carbon atoms such as a benzoyloxy group.

n is preferably 1.
R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ are preferably hydrogen atoms.
R ³ is preferably a hydrocarbon group having 1 to 12 carbon atoms (-CH ₂ − contained in the hydrocarbon group having 1 to 12 carbon atoms may be replaced by −O −). An alkyl group having 1 to 8 carbon atoms (-CH ₂ − contained in the alkyl group having 1 to 8 carbon atoms may be replaced by −O −) is more preferable, and an alkyl group having 1 to 4 carbon atoms is more preferable. _{(-CH 2} − contained in the alkyl group having 1 to 8 carbon atoms may be replaced with −O −).

Examples of the cation of the salt (I) include cations represented by the following formulas (I-c-1) to (I-c-15).

Of these, the cations represented by the formulas (I-c-1) to (I-c-10) are preferable, and the cations represented by the formulas (I-c-1) to (I-c-6) are preferable. Is more preferable, and cations represented by the formulas (I-c-1), (I-c-4), (I-c-5) and (I-c-6) are even more preferable. The cations represented by Ic-1), formula (Ic-4) and formula (Ic-6) are even more preferred.

The perfluoroalkyl group of Q ¹ and Q ^2, a trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, a perfluoro sec- butyl group, perfluoro-tert- butyl group, perfluoropentyl group, and a perfluoro A hexyl group and the like can be mentioned.
Q ¹ and Q ² are preferably fluorine atoms or trifluoromethyl groups independently of each other, and more preferably both are fluorine atoms.

Examples of the divalent saturated hydrocarbon group of L ^b1 include a linear or branched alkanediyl group and a monocyclic or polycyclic divalent alicyclic saturated hydrocarbon group, among these groups. It may be a group formed by combining two or more kinds.
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, Nonan-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. Alcandiyl group;
Ethan-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, 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, etc. Valuable 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. The group etc. can be mentioned.

［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−ＣＨ_２−は、−Ｏ−又は−ＣＯ−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−ＣＨ_２−は、−Ｏ−又は−ＣＯ−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−ＣＨ_２−は、−Ｏ−又は−ＣＯ−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。］ _{Examples of the group in which -CH 2-} contained in the divalent saturated hydrocarbon group of L ^b1 is replaced with -O- or -CO- are any of the formulas (b1-1) to (b1-3). The group represented by is mentioned. In the formulas (b1-1) to (b1-3) and the following specific examples, * represents a bond with −Y.

[In equation (b1-1),
L ^b2 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the 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, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated hydrocarbon group may be substituted. _{-CH 2-} contained in the hydrocarbon group may be replaced with -O- or -CO-.
However, the total number of carbon atoms of ^{L b2} and L ^{b3 is 22 or less.}
In equation (b1-2),
L ^b4 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the 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, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated hydrocarbon group may be substituted. _{-CH 2-} contained in the hydrocarbon group may be replaced with -O- or -CO-.
However, the total number of carbon atoms of ^{L b4} and L ^{b5 is 22 or less.}
In equation (b1-3),
L ^b6 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the 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, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group, and the saturated hydrocarbon group may be substituted. _{-CH 2-} contained in the hydrocarbon group may be replaced with -O- or -CO-.
However, the total number of carbon atoms of ^{L b6} and L ^{b7 is 23 or less.} ]

In the formulas (b1-1) to (b1-3), when -CH _2- contained in the saturated hydrocarbon group is replaced with -O- or -CO-, the number of carbon atoms before the replacement is the saturated hydrocarbon. Let it be the number of carbon atoms of the hydrogen group.
Examples of the divalent saturated hydrocarbon group include those similar to the divalent saturated hydrocarbon group of ^{L b1.}

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 the hydrogen atom contained in the divalent 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 the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom.
L ^b7 is preferably a single-bonded or divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and the 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 divalent saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
The _{group in which -CH 2-} contained in the divalent saturated hydrocarbon group of ^{L b1} is replaced with -O- or -CO- is a group represented by the formula (b1-1) or the 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２価の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２価の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２価の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^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２価の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^ｂ１８の合計炭素数は１９以下である。］ Examples of the formula (b1-1) include groups represented by the formulas (b1-4) to (b1-8).

[In equation (b1-4),
L ^b8 represents a single bond or a divalent saturated hydrocarbon group having 1 to 22 carbon atoms, and the hydrogen atom contained in the saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
In equation (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 the hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. .. However, the total number of carbon atoms of ^{L b9} and L ^{b10 is 20 or less.}
In equation (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 the hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. .. However, the total number of carbon atoms of ^{L b11} and L ^{b12 is 21 or less.}
In equation (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 the hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. .. However, the total number of carbon atoms of ^{L b13 to} L ^{b15 is 19 or less.}
In equation (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 the hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group. .. However, the total number of carbon atoms of ^{L b16 to} L ^{b18 is 19 or less.} ]

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 divalent saturated hydrocarbon group having 1 to 19 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
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 divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
L ^b15 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 18 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 8 carbon atoms.
L ^b16 is preferably a divalent saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b17 is preferably a divalent saturated hydrocarbon group having 1 to 6 carbon atoms.
L ^b18 is preferably a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and more preferably a single bond or a divalent saturated hydrocarbon group having 1 to 4 carbon atoms.

［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２価の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２価の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−ＣＨ_２−は、−Ｏ−又は−ＣＯ−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２価の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２価の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−ＣＨ_２−は、−Ｏ−又は−ＣＯ−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^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２価の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２価の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−ＣＨ_２−は、−Ｏ−又は−ＣＯ−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^ｂ２６の合計炭素数は２１以下である。］ Examples of the formula (b1-3) include groups represented by the formulas (b1-9) to (b1-11).

[In equation (b1-9),
L ^b19 represents a single bond or a divalent saturated hydrocarbon group having 1 to 23 carbon atoms, and the hydrogen atom contained in the divalent 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 the hydrogen atom contained in the divalent saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an acyloxy group. May be good. _{-CH 2-} contained in the acyloxy group may be replaced with -O- or -CO-, and the hydrogen atom contained in the acyloxy group may be replaced with a hydroxy group. However, the total number of carbon atoms of ^{L b19} and L ^{b20 is 23 or less.}
In equation (b1-10),
L ^b21 represents a single bond or a divalent saturated hydrocarbon group having 1 to 21 carbon atoms, and the hydrogen atom contained in the divalent 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 the hydrogen atom contained in the divalent saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an acyloxy group. You may. _{-CH 2-} contained in the acyloxy group may be replaced with -O- or -CO-, and the hydrogen atom contained in the acyloxy group may be replaced with a hydroxy group. However, the total number of carbon atoms of ^{L b21 to} L ^{b23 is 21 or less.}
In equation (b1-11),
L ^b24 represents a single bond or a divalent saturated hydrocarbon group having 1 to 20 carbon atoms, and the hydrogen atom contained in the divalent 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 the hydrogen atom contained in the divalent saturated hydrocarbon group is substituted with a fluorine atom, a hydroxy group or an acyloxy group. You may. _{-CH 2-} contained in the acyloxy group may be replaced with -O- or -CO-, and the hydrogen atom contained in the acyloxy group may be replaced with a hydroxy group.
^However, the total number of carbon atoms of L b24 ^{~L b26} is 21 or less. ]

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

Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, a cyclohexylcarbonyloxy group, an adamantylcarbonyloxy group and the like.
Examples of the acyloxy group having a substituent include an oxoadamantylcarbonyloxy group, a hydroxyadamantylcarbonyloxy group, an oxocyclohexylcarbonyloxy group, a hydroxycyclohexylcarbonyloxy group and the like.

Examples of the group represented by the formula (b1-4) include the following.

Examples of the group represented by the formula (b1-5) include the following.

Examples of the group represented by the formula (b1-6) include the following.

Examples of the group represented by the formula (b1-7) include the following.

Examples of the group represented by the formula (b1-8) include the following.

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

Examples of the group represented by the formula (b1-9) include the following.

Examples of the group represented by the formula (b1-10) include the following.

Examples of the group represented by the formula (b1-11) include the following.

Examples of the alicyclic hydrocarbon group represented by Y include groups represented by formulas (Y1) to (Y11) and formulas (Y36) to (Y38).
_{When -CH 2-} contained in the alicyclic hydrocarbon group represented by Y is replaced by -O-, -SO _2- or -CO-, the number may be one or a plurality of two or more. .. Examples of such a group include groups represented by the formulas (Y12) to (Y35).

Among them, it is preferably a group represented by any one of the formulas (Y1) to (Y20), formula (Y30), and formula (Y31), and more preferably the formulas (Y11), formulas (Y15), and formulas (Y11). It is a group represented by Y16), formula (Y20), formula (Y30) or formula (Y31), and more preferably a group represented by formula (Y11), formula (Y15) or formula (Y30).
When Y constitutes a spiro ring of formulas (Y28) to (Y33), the alkanediyl group between the two oxygens preferably has one or more fluorine atoms. Further, among the alkanediyl groups contained in the ketal structure, those in which the fluorine atom is not substituted in the methylene group adjacent to the oxygen atom are preferable.

As the substituent of the alicyclic hydrocarbon group represented by Y, an alkyl group having 1 to 12 carbon atoms which may be substituted with a halogen atom, a hydroxy group or a hydroxy group, and an alicyclic group having 3 to 16 carbon atoms Hydrocarbon groups, alkoxy groups with 1 to 12 carbon atoms, aromatic hydrocarbon groups with 6 to 18 carbon atoms, aralkyl groups with 7 to 21 carbon atoms, acyl groups with 2 to 4 carbon atoms, glycidyloxy groups or-(CH) ₂ ) _ja- O-CO-R ^b1 group (in the formula, R ^b1 is an alkyl group having 1 to 16 carbon atoms, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, or an aromatic hydrocarbon having 6 to 18 carbon atoms. It represents a hydrocarbon group. Ja represents an integer of 0 to 4) and the like.

Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alicyclic hydrocarbon group include a cyclopentyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a cycloheptyl group, a cyclooctyl group, a norbornyl group, an adamantyl group and the like.
Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthryl group, a p-methylphenyl group, a p-tert-butylphenyl group and a p-adamantylphenyl group; a trill group, a xsilyl group, a cumenyl group and a mesityl group. , Biphenyl group, phenanthryl group, aryl group such as 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl and the like.
Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an n-hexyl group, a heptyl group, and 2 -Ethylhexyl group, octyl group, nonyl group, decyl group, undecyl group, dodecyl group and the like can be mentioned.
Examples of the alkyl group substituted with the hydroxy group include hydroxyalkyl groups such as a hydroxymethyl group and a hydroxyethyl group.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxy group.
Examples of the aralkyl group include a benzyl group, a phenethyl group, a phenylpropyl group, a naphthylmethyl group and a naphthylethyl group.
Examples of the acyl group include an acetyl group, a propionyl group, a butyryl group and the like.
Examples of the alicyclic hydrocarbon group represented by R ^b1 include the same alicyclic hydrocarbon as the substituent of Y.
Examples of the aromatic hydrocarbon represented by R ^b1 include the same aromatic hydrocarbon as the substituent of Y.
Examples of the alkyl group having 1 to 16 carbon atoms represented by R ^b1 include the same alkyl group as the alkyl group which is a substituent of Y.

Examples of Y include the following.

When Y is a methyl group and L ^b1 is a divalent linear or branched saturated hydrocarbon group having 1 to 24 carbon atoms, the divalent saturated hydrocarbon group at the bonding position with Y It is preferable that −CH ₂₋ is replaced with −O− or −CO−.

Y is preferably an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and more preferably an adamantyl group which may have a substituent, and is said to be an alicyclic hydrocarbon. is -O - - -CH ₂ constituting a hydrogen group or an adamantyl group, - SO ₂ - or -CO- may be replaced with. Y is more preferably an adamantyl group, a hydroxyadamantyl group, an oxoadamantyl group or a group represented by the following.

The sulfonic acid anion in the salt (I) is an anion represented by the formulas (B1-A-1) to (B1-A-55) [hereinafter, "anion (B1-A-1)" according to the formula number. "And so on. ] Are preferable, and formulas (B1-A-1) to (B1-A-4), formulas (B1-A-9), formulas (B1-A-10), formulas (B1-A-24) to formulas (B1-A-24) to formulas. (B1-A-33), formulas (B1-A-36) to formulas (B1-A-40), formulas (B1-A-47) to formulas (B1-A-55). Anions are more preferred.

Here, R ^{i2 to} R ⁱ⁷ represent an alkyl group having 1 to 4 carbon atoms, and are preferably a methyl group or an ethyl group. ^Ri8 represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, an alicyclic hydrocarbon group having 5 to 12 carbon atoms, or a combination thereof. Group, more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group. L ⁴ is a single bond or an alkanediyl group having 1 to 4 carbon atoms. Q ¹ and ^{Q 2} are the same as above.

Examples of the sulfonic acid anion in the salt (I) include anions represented by the formulas (B1a-1) to (B1a-34).

Among them, it is represented by any of the formulas (B1a-1) to (B1a-3), the formulas (B1a-7) to (B1a-19), and the formulas (B1a-22) to (B1a-34). Anions are preferred.

The salt (I) can be arbitrarily combined with these anions and cations. Specific examples of the salt (I) are shown in Tables 1 to 6.

In Table 1, the salt (I-1) is the salt shown below.

As the salt (I), (I-1) to (I-3), (I-16) to (I-19), (I-22) to (I-25), (I-38) to ( I-41), (I-44) to (I-47), (I-60) to (I-63), (I-66) to (I-69), (I-82) to (I- 85), (I-88) to (I-91), (I-104) to (I-107), (I-110) to (I-113), (I-126) to (I-129) , (I-132), (I-133) to (I-135), (I-144), (I-145), (I-148), (I-149) to (I-151), ( I-154) to (I-157), (I-170) to (I-173), (I-176) to (I-179), (I-192) to (I-195), (I- The salts represented by 198) to (I-201), (I-214) to (I-217) and (I-220) are preferable.

（式中、Ｒ^１〜Ｒ^１１、Ｑ¹、Ｑ²、Ｌ^ｂ１及びＹは、前記と同義である。
Ｒ^１１ａ〜Ｒ^１３ａは、それぞれ独立に、水素原子又は炭素数１〜１２のアルキル基を表す。
Ｒ^１４ａは、水素原子又は炭素数１〜１２の炭化水素基を表す。）
溶剤としては、アセトニトリル、クロロホルム等が挙げられる。
式（Ｉ−ｂ）で表される塩としては、下記式で表される塩等が挙げられ、市場より容易に入手できる。

The salt (I) can be produced by reacting a salt represented by the formula (Ia) with a salt represented by the formula (Ib) in a solvent.

(In the formula, R ^{1 to} R ¹¹ , Q ¹ , Q ² , L ^{b 1} and Y have the same meanings as described above.
R ^{11a to} R ^13a independently represent a hydrogen atom or an alkyl group having 1 to 12 carbon atoms.
R ^14a represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms. )
Examples of the solvent include acetonitrile, chloroform and the like.
Examples of the salt represented by the formula (Ib) include salts represented by the following formula, which can be easily obtained from the market.

溶剤としては、アセトニトリル、クロロホルム等が挙げられる。
触媒としては、酢酸銅（ＩＩ）等が挙げられる。 The salt represented by the formula (Ia) is obtained by reacting the salt represented by the formula (Ic) with the compound represented by the formula (Id) in a solvent in the presence of a catalyst. Can be manufactured.

Examples of the solvent include acetonitrile, chloroform and the like.
Examples of the catalyst include copper acetate (II) and the like.

Examples of the salt represented by the formula (Ic) include salts represented by the following formula, which can be easily obtained from the market.

Examples of the compound represented by the formula (Id) include compounds represented by the following formula, which are easily available on the market.

溶剤としては、アセトニトリル、クロロホルム等が挙げられる。
触媒としては、酢酸銅（ＩＩ）等が挙げられる。 Further, the salt (I) can be produced by reacting a salt represented by the formula (Ie) with a salt represented by the formula (Id) in a solvent in the presence of a catalyst. ..

Examples of the solvent include acetonitrile, chloroform and the like.
Examples of the catalyst include copper acetate (II) and the like.

溶剤としては、アセトニトリル、クロロホルム等が挙げられる。 The salt represented by the formula (Ie) can be produced by reacting the salt represented by the formula (Ic) with the salt represented by the formula (Ib) in a solvent. can.

Examples of the solvent include acetonitrile, chloroform and the like.

<Resist composition>
The resist composition contains a resin having an acid unstable group (hereinafter sometimes referred to as "resin (A)") and a salt (I). The salt (I) may contain two or more types, and preferably two or more types.
The salt (I) can act as an acid generator in the resist composition. The content of the salt (I) is preferably 1 to 40 parts by mass, and more preferably 3 to 35 parts by mass with respect to 100 parts by mass of the resin (A).
The resist composition may further contain an acid generator known in the field of resist (hereinafter, may be referred to as "acid generator (B)"). The resist composition preferably contains a quencher (hereinafter sometimes referred to as "quencher (C)") and preferably contains a solvent (hereinafter sometimes referred to as "solvent (D)").

<Acid generator (B)>
The acid generator (B) may be an ionic acid generator or a nonionic acid generator. Preferably, it is an ionic acid generator. Examples of the ionic acid generator include an ionic acid generator composed of a combination of a known cation and a known anion.

［式（Ｂ１）中、
Ｑ^ｂ１及びＱ^ｂ２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。
Ｌ^１は、炭素数１〜２４の２価の飽和炭化水素基を表し、該２価の飽和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く、該２価の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。
Ｙ^１は、置換基を有していてもよいメチル基又は置換基を有していてもよい炭素数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−ＣＨ_２−は、−Ｏ−、−ＳＯ_２−又は−ＣＯ−に置き換わっていてもよい。
Ｚ^＋は、有機カチオンを表す。］ The acid generator (B) is preferably a fluorine-containing acid generator, and more preferably a salt represented by the formula (B1) (hereinafter, may be referred to as “acid generator (B1)”).

[In equation (B1),
Q ^b1 and Q ^b2 independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
L ¹ represents a divalent saturated hydrocarbon group having 1 to 24 carbon atoms, and -CH _2- contained in the divalent saturated hydrocarbon group may be replaced with -O- or -CO-. , The hydrogen atom contained in the divalent saturated hydrocarbon group may be substituted with a fluorine atom or a hydroxy group.
Y ¹ represents a methyl group which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent, and is contained in the alicyclic hydrocarbon group. -CH _2- may be replaced with -O-, -SO _{2- or -CO-.}
Z ⁺ represents an organic cation. ]

^Examples of Q b1 and Q ^b2 are the same as those of the salt (I) Q ¹ and Q ^2.
L ¹ may be the same ^{as L b} 1 of the salt (I).
Y ¹ may be the same as Y of the salt (I).

Examples of the Z ⁺ organic cation include an organic onium cation, for example, an organic sulfonium cation, an organic iodine cation, an organic ammonium cation, a benzothiazolium cation, an organic phosphonium cation, and the like, preferably an organic sulfonium cation or an organic iodine cation. These include, more preferably aryl sulfonium cations.
^{Z +} in the formula (B1) is preferably a cation represented by any of the formulas (b2-1) to (b2-4) [hereinafter, "cation (b2-1)" or the like according to the formula number. In some cases. ].

［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、それらが結合する硫黄原子とともに環を形成してもよく、該環に含まれる−ＣＨ_２−は、−Ｏ−、−ＳＯ−又は−ＣＯ−に置き換わってもよい。
Ｒ^ｂ７及びＲ^ｂ８は、それぞれ独立に、ヒドロキシ基、炭素数１〜１２の脂肪族炭化水素基又は炭素数１〜１２のアルコキシ基を表す。
ｍ２及びｎ２は、それぞれ独立に０〜５のいずれかの整数を表す。
ｍ２が２以上のとき、複数のＲ^ｂ７は同一であっても異なってもよく、ｎ２が２以上のとき、複数のＲ^ｂ８は同一であっても異なってもよい。
Ｒ^ｂ９及びＲ^ｂ１０は、それぞれ独立に、炭素数１〜３６の脂肪族炭化水素基又は炭素数３〜３６の脂環式炭化水素基を表す。
Ｒ^ｂ９とＲ^ｂ１０とは、それらが結合する硫黄原子とともに環を形成してもよく、該環に含まれる−ＣＨ_２−は、−Ｏ−、−ＳＯ−又は−ＣＯ−に置き換わってもよい。
Ｒ^ｂ１１は、水素原子、炭素数１〜３６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６〜１８の芳香族炭化水素基を表す。
Ｒ^ｂ１２は、炭素数１〜１２の脂肪族炭化水素基、炭素数３〜１８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を表し、該脂肪族炭化水素に含まれる水素原子は、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、該芳香族炭化水素基に含まれる水素原子は、炭素数１〜１２のアルコキシ基又は炭素数１〜１２のアルキルカルボニルオキシ基で置換されていてもよい。
Ｒ^ｂ１１とＲ^ｂ１２とは、一緒になってそれらが結合する−ＣＨ−ＣＯ−を含む環を形成していてもよく、該環に含まれる−ＣＨ_２−は、−Ｏ−、−ＳＯ−又は−ＣＯ−に置き換わってもよい。
Ｒ^ｂ１３〜Ｒ^ｂ１８は、それぞれ独立に、ヒドロキシ基、炭素数１〜１２の脂肪族炭化水素基又は炭素数１〜１２のアルコキシ基を表す。
Ｌ^ｂ３１は、−Ｓ−又は−Ｏ−を表す。
ｏ２、ｐ２、ｓ２、及びｔ２は、それぞれ独立に、０〜５のいずれかの整数を表す。
ｑ２及びｒ２は、それぞれ独立に、０〜４のいずれかの整数を表す。
ｕ２は、０又は１を表す。
ｏ２が２以上のとき、複数のＲ^ｂ１３は同一であっても異なってもよく、ｐ２が２以上のとき、複数のＲ^ｂ１４は同一であっても異なってもよく、ｑ２が２以上のとき、複数のＲ^ｂ１５は同一であっても異なってもよく、ｒ２が２以上のとき、複数のＲ^ｂ１６は同一であっても異なってもよく、ｓ２が２以上のとき、複数のＲ^ｂ１７は同一であっても異なってもよく、ｔ２が２以上のとき、複数のＲ^ｂ１８は同一であっても異なってもよい。］

[In equations (b2-1) to (b2-4),
R ^{b4 to} R ^b6 independently represent 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 atom contained in the alicyclic hydrocarbon group is 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. The 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 form a ring together with the sulfur atom to which they are bonded, and -CH _2- contained in the ring may be replaced with -O-, -SO- or -CO-. ..
R ^b7 and R ^b8 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, the plurality of R ^b7s may be the same or different, and when n2 is 2 or more, the plurality of R ^b8s may be the same or different.
R ^b9 and R ^b10 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 form a ring together with the sulfur atom to which they are bonded, and -CH _2- contained in the ring may be replaced with -O-, -SO- or -CO-. ..
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 is contained in the aliphatic hydrocarbon group. The hydrogen atom may be substituted with an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the hydrogen atom contained in the aromatic hydrocarbon group may be an alkoxy group having 1 to 12 carbon atoms or 1 to 12 carbon atoms. It may be substituted with 12 alkylcarbonyloxy groups.
R ^b11 and R ^b12 may be combined to form a ring containing -CH-CO- to which they are bonded, and -CH _2- contained in the ring is -O-, -SO-. Alternatively, it may be replaced with −CO−.
R ^{b13 to} R ^b18 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 -S- or -O-.
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, a plurality of R ^b13s may be the same or different, and when p2 is 2 or more, a plurality of R ^b14s may be the same or different, and when q2 is 2 or more. , A plurality of R ^b15s may be the same or different, and when r2 is 2 or more, a plurality of R ^b16s may be the same or different, and when s2 is 2 or more, a plurality of R ^b17s may be present. It may be the same or different, and when t2 is 2 or more, a plurality of R ^b18s may be the same or different. ]

The aliphatic hydrocarbon group includes a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group and a 2-ethylhexyl group. Alkyl group of. 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 a monocyclic group or a polycyclic group, and the monocyclic alicyclic hydrocarbon group includes a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group and a cyclo. Cycloalkyl groups such as a heptyl group, a cyclooctyl group and a cyclodecyl group can be mentioned. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a 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, and more preferably 4 to 12 carbon atoms.

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

Examples of the aromatic hydrocarbon group include a phenyl group, a tolyl group, a xsilyl 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, 2-methyl-6-ethylphenyl group and other aryl groups.
When the aromatic hydrocarbon group contains an aliphatic hydrocarbon group or an alicyclic hydrocarbon group, the aliphatic hydrocarbon group having 1 to 18 carbon atoms or the alicyclic hydrocarbon group having 3 to 18 carbon atoms may be used. preferable.
Examples of the aromatic hydrocarbon group in which the hydrogen atom is substituted with an alkoxy group include a p-methoxyphenyl group.
Examples of the aliphatic hydrocarbon group in which the hydrogen atom is substituted with an aromatic hydrocarbon group include an aralkyl group such as a benzyl group, a phenethyl group, a phenylpropyl group, a trityl group, a naphthylmethyl group and a naphthylethyl group.

Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group, a hexyloxy group, a heptyloxy group, an octyloxy group, a decyloxy group and a dodecyloxy group.
Examples of the acyl group include an acetyl group, a propionyl group and a butyryl group.
Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
Examples of the alkylcarbonyloxy group include a methylcarbonyloxy group, an ethylcarbonyloxy group, an n-propylcarbonyloxy group, an isopropylcarbonyloxy group, an n-butylcarbonyloxy group, a sec-butylcarbonyloxy group, and a tert-butylcarbonyloxy group. Examples thereof include a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group and a 2-ethylhexylcarbonyloxy group.

The ^{rings that R b4} and R ^b5 may form with the sulfur atoms to which they are attached are monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. There may be. Examples of this ring include a ring having 3 to 18 carbon atoms, and preferably a ring having 4 to 18 carbon atoms. Examples of the ring containing a sulfur atom include a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring, and specifically, the following ring.

The ^{ring formed by R b9} and R ^b10 together with the sulfur atom to which they are bonded may be monocyclic, polycyclic, aromatic, non-aromatic, saturated or unsaturated. good. Examples of this ring include a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring, and examples thereof include a thiolan-1-ium ring (tetrahydrothiophenium ring) and a thian-1-ium. Rings, 1,4-oxatian-4-ium rings and the like can be mentioned.
The ^{ring formed by R b11} and R ^b12 together may be any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. Examples of this ring include a 3-membered ring to a 12-membered ring, preferably a 3-membered ring to a 7-membered ring, and examples thereof include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring. Be done.

Among the cations (b2-1) to cations (b2-4), cations (b2-1) are preferable.
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.

Examples of the acid generator (B) include organic sulfonic acids and organic sulfonium salts. For example, the acid generation described in JP2013-68914, JP2013-3155, and JP2013-1905. Agents and the like can be mentioned. Specific examples thereof include those represented by formulas (B1-1) to (B1-48), among which formulas (B1-1) to formulas (B1-3) containing aryl sulfonium cations and formulas (B1-3). B1-5) to formula (B1-7), formula (B1-11) to formula (B1-14), formula (B1-20), formula (B1-21) to formula (B1-26), formula (B1) -29), those represented by the formulas (B1-31) to (B1-48), respectively, are particularly preferable.

The acid generator (B) may contain two or more kinds.
The content of the acid generator (B) is preferably 1 to 40% by mass, more preferably 3 to 35% by mass, based on the resin (A).

<Resin (A)>
The resin (A) has a structural unit having no halogen atom and having an acid unstable group (hereinafter, may be referred to as “structural unit (a1)”). The resin (A) preferably further contains a structural unit other than the structural unit (a1). Structural units other than the structural unit (a1) include a structural unit having no halogen atom and no acid-labile group (hereinafter, may be referred to as “structural unit (s)”), a structural unit (a1), and a structural unit. A structural unit other than the structural unit (s) (for example, a structural unit having a halogen atom described later (hereinafter sometimes referred to as "structural unit (a4)"), and a structural unit having a non-eliminating hydrocarbon group described later (hereinafter "" (Sometimes referred to as structural unit (a5)) and other structural units derived from monomers known in the art.

［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、酸素原子又は硫黄原子との結合手を表す。］

［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、酸素原子又は硫黄原子との結合手を表す。］ <Structural unit (a1)>
The structural unit (a1) is derived from a monomer having no halogen atom and having an acid unstable group (hereinafter, may be referred to as “monomer (a1)”).
The acid unstable group contained in the resin (A) preferably contains a group represented by the formula (1) and / or a group represented by the formula (2).

[In the formula (1), R ^{a1 to} R ^a3 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 groups, or R. ^a1 and ^Ra2 are bonded to each other to form a divalent alicyclic hydrocarbon group having 3 to 20 carbon atoms together with the carbon atom to which they are bonded.
na represents 0 or 1.
* Represents a bond with an oxygen atom or a sulfur atom. ]

[In the 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. Represented, 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 and X to which they are bonded, and the hydrocarbon group and the divalent complex. _{The −CH 2−} contained in the ring group may be replaced by −O− or −S−.
X represents an oxygen atom or a sulfur atom.
* Represents a bond with an oxygen atom or a sulfur atom. ]

^Examples of the alkyl group of R ^{a1 to} R a3 include a methyl group, an ethyl group, a propyl group, an n-butyl group, an n-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group and the like.
The alicyclic hydrocarbon groups of R ^{a1 to} R ^a3 may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group. Examples of the polycyclic alicyclic hydrocarbon group include a decahydronaphthyl group, an adamantyl group, a norbornyl group and the following groups (* indicates 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 the group in which the alkyl group and the 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. Can be mentioned.
na is preferably 0.

^{Examples of -C (R a1} ) (R ^a2 ) (R ^a3 ) in the case where R ^a1 and R ^a2 are bonded to each other to form a divalent alicyclic hydrocarbon group include the following groups. The divalent alicyclic hydrocarbon group preferably has 3 to 12 carbon atoms. * Represents a bond with -O-.

Examples of the group represented by the formula (1), 1,1-dialkyl alkoxycarbonyl group (formula (1) ^R a1 ^{to R a3} is mentioned group which is an alkyl group in a, preferably tert- butoxycarbonyl group) , 2-alkyladamantan-2-yloxycarbonyl group (in formula (1), ^Ra1 , ^Ra2 and the carbon atom to which they are bonded form an adamantyl group, and ^Ra3 is an alkyl group) and 1-. Examples thereof include (adamantan-1-yl) -1- ^{alkylalkoxycarbonyl group (in the formula (1), R a1} and R ^a2 are alkyl groups and R ^a3 is an adamantyl group).

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。 Examples of the hydrocarbon group R ^{a1 '~R a3',} an alkyl group, an alicyclic hydrocarbon group, and a group formed by combining an aromatic hydrocarbon group and thereof.
Examples of the alkyl group and the alicyclic hydrocarbon group include the same as above.
Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthryl group, a p-methylphenyl group, a p-tert-butylphenyl group, a p-adamantylphenyl group, a trill group, a xsilyl group, a cumenyl group, a mesityl group and a biphenyl group. Examples thereof include an aryl group such as a group, a phenanthryl group, a 2,6-diethylphenyl group and a 2-methyl-6-ethylphenyl group.
^{Examples of the} divalent heterocyclic group formed by R ^a2'and R a3'bonding to each other together with the carbon atom and X to which they are bonded include the following groups. * Represents a bond.

Of R ^{a1 'and R a2',} it is preferable that at least one is a hydrogen atom.

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

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

Among the (meth) acrylic monomers having an acid unstable group, those having an alicyclic hydrocarbon group having 5 to 20 carbon atoms are preferable. If 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 the structural unit derived from the (meth) acrylic monomer having a group represented by the formula (1), the structural unit represented by the formula (a1-0) is preferably represented by the formula (a1-1). Examples thereof include a structural unit or a structural unit represented by the formula (a1-2). These may be used alone or in combination of two or more. In the present specification, the structural unit represented by the formula (a1-0), the structural unit represented by the formula (a1-1), and the structural unit represented by the formula (a1-2) are each referred to as a structural unit (a1). -0), structural unit (a1-1) and structural unit (a1-2).

[In the formula (a1-0), the formula (a1-1) and the formula (a1-2),
L ^{a01, L a1} and ^{L a2} each independently, -O- or _{^{* -O- (CH 2) k1 -CO}} -O- the stands, k1 represents an integer of 1-7, and * 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 independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group combining these groups.
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 them.
m1 represents any integer from 0 to 14.
n1 represents any integer from 0 to 10.
n1'represents an integer of 0 to 3. ]

L ^{a01, L a1} and ^{L a2} are each independently preferably -O- or _{^{* -O- (CH 2) k01 -CO}} -O- and is (however, k01 are all preferably from 1 to 4 Integer, more preferably 1), more preferably −O−.
R ^a4 and R ^a5 are preferably methyl 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 a methyl group or an ethyl group.
The alicyclic hydrocarbon groups of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 have independently, preferably 3 to 8 carbon atoms, and more preferably 3 to 6 carbon atoms, respectively.
The group in which the alkyl group and the alicyclic hydrocarbon group are combined preferably has a total carbon number of 4 to 18 in which these alkyl groups and the alicyclic hydrocarbon group are combined. Examples of such a group include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a methyladamantyl group, a cyclohexylmethyl group, a methylcyclohexylmethyl group, an adamantylmethyl group, a norbornylmethyl group and the like. 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, and more preferably a methyl group, an ethyl group, a cyclohexyl group or an adamantyl group.
The alkyl groups of R ^a6 and R ^a7 have preferably 6 or less carbon atoms, more preferably 1 to 3 carbon atoms, and further preferably 2 or 3 carbon atoms.
The alicyclic hydrocarbon groups of R ^a6 and R ^a7 have preferably 3 to 8 carbon atoms, more preferably 3 to 6 carbon atoms.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, and 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 of the formulas (a1-0-1) to (a1-0-12) is preferable, and the structural units (a1-0-1) to The structural unit represented by any of the formulas (a1-0-10) is more preferable.

Examples of the structural unit (a1-1) include structural units derived from the monomers described in JP-A-2010-204646. Of these, structural units represented by any of the formulas (a1-1-1) to (a1-1-4) are preferable.

上記の構造単位において、Ｒ^ａ０１、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構造単位も、上記構造単位の具体例として挙げられる。 The structural unit (a1-2) preferably includes a structural unit represented by any of the formulas (a1-2-1) to (a1-2-6), and more preferably the formula (a1-2). -2) and the structural unit represented by the formula (a1-2-5) are preferable.

In the above structural units, R ^{a01, R a4,} structural units in which a methyl group corresponding to R ^a5 is replaced by a hydrogen atom, be mentioned as specific examples of the structural units.

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

［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。］ The structural unit derived from the (meth) acrylic monomer having a group represented by the formula (2) is a structural unit represented by the formula (a1-5) (hereinafter referred to as “structural unit (a1-5)”). There is).

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

Examples of the halogen atom include a fluorine atom and a chlorine atom, and preferably a fluorine atom. Alkyl groups 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. The group is mentioned.
In the formula (a1-5), R ^a8 is preferably a hydrogen atom, a methyl group or a trifluoromethyl group.
L ⁵¹ is preferably an oxygen atom.
Of L ⁵² and L ⁵³ , it is preferable that one is −O− and the other is −S−.
s1 is preferably 1.
s1'is preferably an integer of 0 to 2.
Z ^a1 is preferably a single bond or * -CH _2- CO-O-.

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

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

Further, examples of the structural unit (a1) include the following structural units and structural units in which a hydrogen atom bonded to the main chain of those structural units is replaced with a methyl group.

When the resin (A) contains any of the structural units (a1-3-1) to the structural units (a1-3-7), the content thereof is 10 to 10 with respect to all the structural units of the resin (A). 95 mol% is preferable, 15 to 90 mol% is more preferable, and 20 to 85 mol% is further preferable.

［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いてもよい炭素数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。］ The structural unit having a group represented by the formula (2) in the structural unit (a1) may be referred to as a structural unit represented by the formula (a1-4) (hereinafter, “structural unit (a1-4)”). .) Can be mentioned.

[In equation (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, and acryloyl. Represents an oxy group or a methacryloyloxy group.
la represents any integer from 0 to 4. When la is 2 or more, a plurality of Ra ^33s may be the same or different from each other.
R ^a34 and R ^a35 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms, R ^a36 may represent a hydrocarbon group having 1 to 20 carbon atoms, R ^a35 and R ^a36 are bonded to each other Then, together with -CO- to which they are bonded, a divalent hydrocarbon group having 2 to 20 carbon atoms is formed, and the hydrocarbon group and the −CH ₂ − contained in the divalent hydrocarbon group are − It may be replaced by O- or -S-. ]

^Examples of the alkyl group in R ^a32 and R a33 include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, a hexyl group and the like. The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group or an ethyl group, and even more preferably a methyl group.
Examples of the halogen atom in R ^a32 and R ^a33 include a fluorine atom, a chlorine atom and a bromine atom.
Examples of the alkyl group having 1 to 6 carbon atoms which may have a halogen atom include a trifluoromethyl group, a difluoromethyl group, a methyl group, a perfluoroethyl group, a 1,1,1-trifluoroethyl group, and 1,1. , 2,2-Tetrafluoroethyl group, ethyl group, perfluoropropyl group, 1,1,1,2,2-pentafluoropropyl group, propyl group, perfluorobutyl group, 1,1,2,2,3,3 , 4,4-Octafluorobutyl group, butyl group, perfluoropentyl group, 1,1,1,2,2,3,3,4,4-nonafluoropentyl group, pentyl group, hexyl group, perfluorohexyl group, etc. Can be mentioned.
Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, a pentyloxy group and a hexyloxy group. Of these, an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group or an ethoxy group is more preferable, and a methoxy group is even more preferable.
Examples of the alkylcarbonyl group include an acetyl group, a propionyl group and a butyryl group.
Examples of the alkylcarbonyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group and the like.
As the hydrocarbon group for R ^a34, R ^a35 and R ^a36, an alkyl group, an alicyclic hydrocarbon group, aromatic hydrocarbon group, and include groups formed by combining these, alkyl groups and alicyclic hydrocarbon groups Examples thereof include groups similar to the alkyl groups and alicyclic hydrocarbon groups in R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7.
Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthryl group, a p-methylphenyl group, a p-tert-butylphenyl group, a p-adamantylphenyl group, a trill group, a xsilyl group, a cumenyl group, a mesityl group and a biphenyl group. Examples thereof include an aryl group such as a group, a phenanthryl group, a 2,6-diethylphenyl group and a 2-methyl-6-ethylphenyl group.
Examples of the combined group include a group combining the above-mentioned alkyl group and an alicyclic hydrocarbon group, an aralkyl group such as a benzyl group, and an aryl-cyclohexyl group such as a phenylcyclohexyl group. In particular, ^Ra36 includes an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group formed by combining these groups. Can be mentioned.

In the formula (a1-4), a hydrogen atom is preferable as ^Ra32.
As R ^a33 , an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group and an ethoxy group are more preferable, and a methoxy group is further preferable.
As la, 0 or 1 is preferable, and 0 is more preferable.
R ^a34 is preferably a hydrogen atom.
R ^a35 is preferably an alkyl group or an alicyclic hydrocarbon group having 1 to 12 carbon atoms, and more preferably a methyl group or an ethyl group.
The hydrocarbon group of R ^a36 is preferably an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a combination thereof. It is a group to be formed, more preferably an alkyl group having 1 to 18 carbon atoms, an aliphatic hydrocarbon group having 3 to 18 carbon atoms or an aralkyl group having 7 to 18 carbon atoms. Alkyl group and alicyclic hydrocarbon group for R ^a36 is preferably unsubstituted. Aromatic hydrocarbon group for R ^a36 is an aromatic ring preferably has an aryloxy group having 6 to 10 carbon atoms.

Examples of the structural unit (a1-4) include a structural unit derived from a monomer described in JP-A-2010-204646. Preferably, hydrogen atom corresponding to ^{R a32} in equation (a1-4-1) represented respectively to Formula (a1-4-8) structural units and structural units (a1-4) is replaced by a methyl group structure Units are mentioned, and more preferably, structural units represented by the formulas (a1-4-1) to (a1-4-5) are mentioned.

樹脂（Ａ）が構造単位（ａ１−４）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。

When the resin (A) contains the structural unit (a1-4), the content thereof is preferably 10 to 95 mol%, more preferably 15 to 90 mol%, based on all the structural units of the resin (A). 20-85 mol% is more preferred.

As the structural unit (a1), at least one or more selected from the group consisting of the structural unit (a1-0), the structural unit (a1-1), the structural unit and (a1-2) is preferable, and at least two or more are more. Preferably, a combination of the structural unit (a1-1) and the structural unit (a1-2), a combination of the structural unit (a1-2) and the structural unit (a1-0), the structural unit (a1-1) and the structural unit (a1). A combination of −0), a structural unit (a1-0), a structural unit (a1-1) and a structural unit (a1-2) are more preferable.
The structural unit (a1) preferably includes the structural unit (a1-2).

<Structural unit (a3)>
The resin (A) of the present invention preferably has a structural unit having a lactone ring (hereinafter, may be referred to as “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 β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring, or a fused ring of a monocyclic lactone ring and another ring. But it may be. Preferably, a crosslinked ring containing a γ-butyrolactone ring, an adamantanane lactone ring or a γ-butyrolactone ring structure can be mentioned.

The structural unit (a3) is preferably a structural unit represented by the formula (a3-1), the formula (a3-2), the formula (a3-3), or the formula (a3-4). One of these may be contained alone, or two or more thereof 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、それぞれ独立して、−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、単結合、^＊１−Ｌ^ａ８−Ｏ−、^＊１−Ｌ^ａ８−ＣＯ−Ｏ−、^＊１−Ｌ^ａ８−ＣＯ−Ｏ−Ｌ^ａ９−ＣＯ−Ｏ−又は^＊１−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。
＊１は−Ｏ−との結合手を表す。
Ｒ^ａ１８、Ｒ^ａ１９及びＲ^ａ２０は、それぞれ独立して、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、それぞれ独立して、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 the formula (a3-1), the formula (a3-2), the formula (a3-3) and the formula (a3-4),
^La4 , ^La5 and ^La6 are independently represented by -O- or ^* -O- (CH ₂ ) _k3- CO-O- (k3 represents an integer of 1 to 7). Represents the group to be.
L ^a7 is a single bond, ^{* 1-} L ^a8- O-, ^{* 1-} L ^a8- CO-O-, ^{* 1-} L ^a8- CO-O-L ^a9- CO-O- or ^{* 1-} L ^a8. -O-CO-L ^a9 Represents -O-.
^La8 and ^La9 represent an alkanediyl group having 1 to 6 carbon atoms independently of each other.
* Represents a bond with a carbonyl group.
* 1 represents a bond with −O−.
R ^a18 , R ^a19 and R ^a20 each independently represent a hydrogen atom or a methyl group.
^Ra24 represents an alkyl group having 1 to 6 carbon atoms, a hydrogen atom or a halogen atom which may have a halogen atom.
Ra ²¹ represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms.
R ^a22 , R ^a23 and R ^a25 each independently 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 any integer from 0 to 3.
r1 represents any integer from 0 to 3.
w1 represents any integer from 0 to 8.
When p1, q1, r1 and w1 are 2 or more, a plurality of Ra ^21s , Ra ^22s , Ra ^23s and / or Ra ^25s may be the same or different from each other. ]

Examples of the aliphatic hydrocarbon group having 1 to 4 carbon atoms of R ^a21 , R ^a22 and R ^a23 include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group and a tert-butyl group. Can be mentioned.
^{Examples of the halogen atom of Ra24} include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
^Examples of the alkyl group of R a24 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group and an n-hexyl group. , Preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group or an ethyl group.
^{Alkyl groups having a halogen atom of Ra24} include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec-butyl group, perfluorotert-butyl group, perfluoropentyl group and perfluoro. Examples thereof include a hexyl group, a trichloromethyl group, a tribromomethyl group, and a triiodomethyl group.

The ^{alkanediyl groups of La8} and ^La9 include methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group and 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, Examples thereof include 4-diyl group and 2-methylbutane-1,4-diyl group.

In the formula (a3-1) ~ formula ^(a3-4), L a4 ^{~L a6} are each independently preferably -O- and, k3 is a integer of 1 to 4 * -O- ( CH ₂ ) _{A group represented by k3-} CO-O-, more preferably -O-, * -O-CH _2- CO-O-, and even more preferably -O-.
L ^a7 is preferably a single bond or ^* -L ^a8- CO-O-, more preferably a single bond, -CH _2- CO-O- or -C ₂ H _4- CO-O-.
R ^{a18 to} R ^a21 are preferably methyl groups.
^Ra24 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, and further 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.
p1, q1, r1 and w1 are independently, preferably an integer of 0 to 2, and more preferably 0 or 1.

（式中、Ｒ^ａ２４、Ｌ^ａ７は、上記と同じ意味を表す。） As for the formula (a3-4), the formula (a3-4)'is particularly preferable.

(In the formula, ^Ra24 and ^La7 have the same meanings as above.)

Examples of the monomer for deriving the structural unit (a3) include the monomers described in JP-A-2010-204646, the monomers described in JP-A-2000-122294, and the monomers described in JP-A-2012-41274. Can be mentioned. As the structural unit (a3), a structural unit represented by any of the following is preferable, and formulas (a3-1-1), formulas (a3-2-3) and formulas (a3-4-1) to formulas (a3-4-1) to formulas (a3-4-1) are preferable. The structural unit represented by any one of a3-4-12) is more preferable, and the structural unit represented by any of the formulas (a3-4-1) to (a3-4-12) is more preferable. The structural unit represented by any of the formulas (a3-4-1) to (a3-4-6) is even more preferable.

上記構造単位においては、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ることができる。

In the above structural ^units, compounds having a methyl group replaced by a hydrogen atom corresponding to ^{R a18,} R ^a19, R ^a20 and ^{R a24} may be mentioned as specific examples of the structural units (a3).

When the resin (A) contains the structural unit (a3), the total content thereof is usually 5 to 70 mol%, preferably 10 to 65 mol%, based on the total of all the structural units of the resin (A). It is more preferably 10 to 60 mol%.
The contents of the structural unit (a3-1), the structural unit (a3-2), the structural unit (a3-3), and the structural unit (a3-4) are the sum of all the structural units of the resin (A). On the other hand, it is preferably 5 to 60 mol%, more preferably 5 to 50 mol%, and even more preferably 10 to 50 mol%.

The resin (A) of the present invention preferably further has a structural unit having a hydroxy group and no acid unstable group (hereinafter, may be referred to as “structural unit (a2)”).

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

When the resin (A) has a structural unit (a2) having a phenolic hydroxy group, the content thereof is preferably 5 to 95 mol% with respect to the total of all the structural units of the resin (A). , 10-80 mol%, more preferably 15-80 mol%.

Examples of the structural unit (a2) having an alcoholic hydroxy group include a structural unit represented by the formula (a2-1) (hereinafter, may be referred to as “structural unit (a2-1)”).

［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。］

[In equation (a2-1),
^La3 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 independently represent a hydrogen atom, a methyl group or a hydroxy group, respectively.
o1 represents any integer from 0 to 10. ]

In the formula ^{(a2-1), L a3} is preferably _{-O -, - O- (CH 2} ) f1 -CO-O- and is (wherein f1 is an integer of 1-4), More preferably, it is −O−.
^Ra14 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 of 0 to 3, more preferably 0 or 1.

上記構造単位においては、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。 Examples of the structural unit (a2-1) include structural units derived from the monomers described in JP-A-2010-204646, preferably formulas (a2-1-1) to (a2-). The structural unit represented by any one of 1-3) can be mentioned, and more preferably, the structural unit represented by any of the formulas (a2-1-1) to (a2-1-2) can be mentioned.

In the structural unit, ^{a compound in which the methyl group corresponding to Ra14} is replaced with a hydrogen atom is also mentioned as a specific example of the structural unit.
When the resin (A) contains the structural unit (a2-1), the content thereof is usually 1 to 45 mol%, preferably 1 to 40 mol%, based on the total of all the structural units of the resin (A). %, More preferably 1 to 35 mol%, still more preferably 2 to 20 mol%.

The resin (A) of the present invention may further have a structural unit (a2) and a structural unit other than the structural unit (a3) (hereinafter, may be referred to as “structural unit (t)”).

<Structural unit (t)>
The structural unit (t) includes a structural unit that may have a halogen atom (hereinafter, sometimes referred to as “structural unit (a4)”) and a structural unit that has a non-desorbed hydrocarbon group (hereinafter, “structural unit”). (A5) ”) and the like.

［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。］ Examples of the structural unit (a4) include a structural unit represented by the formula (a4-0).

Wherein (a4-0), ^{R 5} represents a hydrogen atom or a methyl group.
L ⁵ represents a single bond or an aliphatic saturated hydrocarbon group having 1 to 4 carbon atoms.
L ³ represents a perfluoroalkanediyl group having 1 to 8 carbon atoms or a perfluorocycloalkanediyl group having 3 to 12 carbon atoms.
R ⁶ represents a hydrogen atom or a fluorine atom. ]

Examples of the aliphatic saturated hydrocarbon group of L ^5, include alkanediyl group having 1 to 4 carbon atoms, e.g., methylene group, ethylene group, propane-1,3-diyl, butane-1,4-diyl group , Etc., a linear alkanediyl group having a side chain of an alkyl group (particularly, a methyl group, an ethyl group, etc.), an ethane-1,1-diyl group, a propane-1, Examples thereof include 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.

Examples of the perfluoroalkanediyl group of L ³ include a difluoromethylene group, a perfluoroethylene group, a perfluoropropane-1,1-diyl 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 Examples thereof include -2,2-diyl group, perfluorooctane-3,3-diyl group, perfluorooctane-4,4-diyl group and the like.
Examples of the perfluorocycloalkanediyl group of L ³ include a perfluorocyclohexanediyl group, a perfluorocyclopentanediyl group, a perfluorocycloheptanediyl group, a perfluoroadamantandiyl group and the like.

L ⁵ represents 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 perfluoroalkanediyl group having 1 to 6 carbon atoms, and more preferably a perfluoroalkanediyl group having 1 to 3 carbon atoms.

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

［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。ただし、Ａ^ａ４１及びＲ^ａ４２のうち少なくとも１つは、置換基としてハロゲン原子（好ましくはフッ素原子）を有する。 The structural unit (a4) also includes a structural unit represented by the formula (a4-1).

[In the formula (a4-1), Ra ⁴¹ represents a hydrogen atom or a methyl group.
R ^a42 represents a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, and -CH _2- contained in the hydrocarbon group may be replaced with -O- or -CO-. good.
^Aa41 represents an alkanediyl group having 1 to 6 carbon atoms which may have a substituent or a group represented by the formula (ag1). However, ^{at least one of Aa41} and ^Ra42 has a halogen atom (preferably a fluorine atom) as a substituent.

［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。］

[In the formula (ag1), 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 divalent aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a single bond or a substituent.
X ^a41 and X ^a42 independently represent -O-, -CO-, -CO-O- or -O-CO-, respectively.
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 side is the bond with -O-CO-R ^a42 . ]

^Examples of the hydrocarbon group of R a42 include a chain type and a ring type aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these groups.
Chain and cyclic aliphatic hydrocarbon groups may have carbon-carbon unsaturated bonds, but are formed by chain and cyclic aliphatic saturated hydrocarbon groups and their combination. Groups are preferred. The aliphatic saturated hydrocarbon group is a fat formed by combining a linear or branched alkyl group and a monocyclic or polycyclic alicyclic hydrocarbon group, and an alkyl group and an alicyclic hydrocarbon group. Group hydrocarbon groups and the like can be mentioned.

芳香族炭化水素基としては、フェニル基、ナフチル基、アントリル基、ビフェニリル基、フェナントリル基及びフルオレニル基が挙げられる。 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. Examples thereof include a group, an n-dodecyl group, an n-pentadecyl group, an n-hexadecyl group, an n-heptadecyl group and an n-octadecyl group. Cyclic aliphatic hydrocarbon groups include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group and cyclooctyl group; decahydronaphthyl group, adamantyl group, norbornyl group and the following groups (* is a bond). Examples thereof include a polycyclic alicyclic hydrocarbon group such as (representing a hand).

Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an anthryl group, a biphenylyl group, a phenanthryl group and a fluorenyl group.

［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。］ ^Examples of the substituent of R a42 include a halogen atom or a group represented by the formula (ag3). Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, and a fluorine atom is preferable.

[In the formula ( ^ag3 ), X a43 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ^a45 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms having at least one halogen atom.
* Represents a bond. ]

Examples of the aliphatic hydrocarbon group of A ^{a45 include} the same groups as those exemplified in ^{Ra 42.}
R ^a42 is preferably an aliphatic hydrocarbon group which may have a halogen atom, and is an alkyl group having a halogen atom and / or an aliphatic hydrocarbon group having a group represented by the formula (ag3). 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, and even 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. Examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group and a perfluorooctyl group. Examples of the perfluorocycloalkyl group include a perfluorocyclohexyl group.
When R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula (ag3), the aliphatic hydrocarbon includes the number of carbon atoms contained in the group represented by the formula (ag3). The total carbon number of the group is preferably 15 or less, more preferably 12 or less. When the group represented by the formula (ag3) is used as a substituent, the number thereof is preferably one.

A more preferable structure of the group represented by the formula (ag3) is the following structure.

The ^{alkanediyl group of A a41} includes a methylene group, an ethylene group, a propane-1,3-diyl group, a butane-1,4-diyl group, a pentane-1,5-diyl group, and a hexane-1,6-diyl group. Linear alkanediyl groups such as propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,2-diyl group, 1-methylbutane-1,4-diyl group, etc. Examples thereof include branched alkanediyl groups such as 2-methylbutane-1,4-diyl group.
^Examples of the substituent in the alkanediyl group of Aa41 include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.
A ^a41 is preferably an alkanediyl group having 1 to 4 carbon atoms, more preferably an alkanediyl group having 2 to 4 carbon atoms, and further preferably an ethylene group.

^{The aliphatic hydrocarbon groups A a42} , A ^a43 and A ^{a44 in} the group (a-g1) may have a carbon-carbon unsaturated bond, but are preferably aliphatic saturated 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 an alkyl group and an alicyclic hydrocarbon group are combined. Examples thereof include an aliphatic hydrocarbon group formed by. Specifically, a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a 1-methylpropane-1,3-diyl group, Examples thereof include 2-methylpropane-1,3-diyl group and 2-methylpropane-1,2-diyl group.
^Examples of the substituent of the aliphatic hydrocarbon group 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 0.

^{Examples of the group (ag1) 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 ** represent a bond, respectively, and ** is a bond with -O-CO-R ^a42 .

Examples of the structural unit represented by the formula (a4-1) include the structural unit described below and the structural unit in which the methyl group corresponding to ^{Ra41 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。］ The structural unit (a4) also includes a structural unit represented by the formula (a4-4).

[In formula (a4-4), R ^f21 represents a hydrogen atom or a methyl group.
A ^f21 _{is, - (CH 2) j1 -} , - (CH 2) j2 -O- (CH 2) j3 - or _{- (CH 2) j4 -CO-} O- (CH 2) j5 - represents a.
j1 to j5 each independently represent an integer of 1 to 6.
R ^f22 represents a hydrocarbon group having 1 to 10 carbon atoms having a fluorine atom. ]

^Examples of the hydrocarbon group having a fluorine atom of R f22 include an alkyl group having 1 to 10 carbon atoms having a fluorine atom and an alicyclic hydrocarbon group having 3 to 10 carbon atoms having a fluorine atom. 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, 1,1,2,2,3,3,4,5-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 , 2,3,3,4,5,5-decafluorohexyl group, 1,1,2,2,3,4,4,5,5,6-dodecafluorohexyl group, perfluoro Examples thereof include a pentylmethyl group, a perfluorohexyl group, a perfluorocyclohexyl group, and a perfluoroadamantyl group. It is preferably an alkyl group having 1 to 10 carbon atoms having a fluorine atom, and more preferably an alkyl group having 1 to 6 carbon atoms having a fluorine atom.

In the formula (a4-4), as A ^f21 , − (CH ₂ ) _j1 − is preferable, an ethylene group or a methylene group is more preferable, and a methylene group is further preferable.

Examples of the structural unit represented by the formula (a4-4) include the following structural units and structural units in which the methyl group corresponding to ^{R f21 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 the structural units of the resin (A). Is more preferable, and 3 to 10 mol% is further preferable.

［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 the non-eliminating hydrocarbon group contained in the structural unit (a5) include a linear, branched or cyclic hydrocarbon group. Among them, the structural unit (a5) is preferably a group having an alicyclic hydrocarbon group.
Examples of the structural unit (a5) include a structural unit represented by the formula (a5-1).

[In formula (a5-1), R ⁵¹ represents a hydrogen atom or a methyl group.
R ⁵² represents an alicyclic hydrocarbon group having 3 to 18 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group may be substituted with an aliphatic hydrocarbon group having 1 to 8 carbon atoms. ..
However, ^{the hydrogen atom bonded to the carbon atom at the bonding position with L 55} is not replaced by 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 of R ⁵² may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic hydrocarbon group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group and a cyclohexyl group. Examples of the polycyclic alicyclic hydrocarbon group include an adamantyl group and a norbornyl group.
Examples of the aliphatic hydrocarbon group having 1 to 8 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group. , Alkyl groups such as octyl group and 2-ethylhexyl group.
Examples of the alicyclic hydrocarbon group having a substituent include a 3-methyladamantyl group.
R ⁵² is preferably an unsubstituted alicyclic hydrocarbon group having 3 to 18 carbon atoms, and more preferably an adamantyl group, a norbornyl group or a cyclohexyl group.

Examples of the divalent saturated hydrocarbon group of L ⁵⁵ include a divalent aliphatic saturated hydrocarbon group and a divalent alicyclic saturated hydrocarbon group, preferably a divalent aliphatic saturated hydrocarbon group. Be done.
Examples of the divalent aliphatic saturated hydrocarbon group include an alkanediyl group such as a methylene group, an ethylene group, a propanediyl group, a butanjiyl group and a pentandiyl group.
The divalent alicyclic saturated hydrocarbon group may be either monocyclic or polycyclic. Examples of the monocyclic alicyclic saturated hydrocarbon group include a cycloalkanediyl group such as a cyclopentanediyl group and a cyclohexanediyl group. Examples of the polycyclic divalent alicyclic saturated hydrocarbon group include an adamantandiyl 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 described below. * Represents a bond with an oxygen atom.

Examples of the structural unit (a5-1) include the following and a structural unit in which a methyl group corresponding to ^{R 51 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 the structural units of the resin (A). Is more preferable, and 3 to 15 mol% is further preferable.

The structural unit (s) is preferably at least one of the structural unit (a2) and the structural unit (a3). The structural unit (a2) is preferably a structural unit represented by the formula (a2-1). The structural unit (a3) is preferably a structural unit represented by the formulas (a3-1-1) to (a3-1-4), and the formulas (a3-2-1) to (a3-2-4). It is at least one selected from the structural unit represented by and the structural unit represented by the formulas (a3-4-1) to (a3-4-2).

Each structural unit constituting the resin (A) may be used in combination of two or more, and can be produced by a known polymerization method (for example, a radical polymerization method) using a monomer for inducing these structural units. .. The content of each structural unit of the resin (A) can be adjusted by adjusting the amount of the monomer used for the 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, still more preferable. Is 15,000 or less). In the present specification, the weight average molecular weight is a value obtained by gel permeation chromatography under the conditions described in Examples.

<Resin other than resin (A)>
The resist composition of the present invention may contain a resin other than the resin (A). Examples of such a resin include a resin composed of only the structural unit (s) and a resin containing the structural unit (a4) (however, the resin does not include the structural unit (a1), and may be hereinafter referred to as "resin (X)". ), And the resin (X) is preferable.
In the resin (X), the content of the structural unit (a4) is preferably 40 mol% or more, more preferably 45 mol% or more, still more preferably 50 mol% or more, based on all the structural units of the resin (X). ..
Examples of the structural unit that the resin (X) may further include include a structural unit (a2), a structural unit (a3), and a structural unit derived from other known monomers.
The weight average molecular weight of the 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 the resin (X) is the same as that of the resin (A).
When the resist composition contains the resin (X), the content thereof is preferably 1 to 60 parts by mass, more preferably 1 to 50 parts by mass, and further, with respect to 100 parts by mass of the resin (A). It is preferably 1 to 40 parts by mass, and particularly preferably 2 to 30 parts by mass.

The total content of the resin (A) and the resin other than the resin (A) is preferably 80% by mass or more and 99% by mass or less with respect to the solid content of the resist composition. The solid content of the resist composition and the content of the resin relative to the solid content can be measured by a known analytical means such as liquid chromatography or gas chromatography.

<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 a 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. Esters; ketones such as acetone, methylisobutylketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; and the like. One type of solvent (E) may be contained alone, or two or more types may be contained.

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

<Basic nitrogen-containing organic compounds>
Examples of the basic nitrogen-containing organic compound include amine and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines 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, trypentylamine, 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) ethane, 1,3-di (4-pyridyl) propane, 1,2-di (4-pyridyl) Oxy) ethane, di (2-pyridyl) ketone, 4,4'-dipyridyl sulfide, 4,4'-dipyridyl disulfide, 2,2'-dipyridylamine, 2,2'-dipicorylamine, 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, choline and the like can be mentioned.

<Salt that generates acid with weak acidity>
The acidity of a salt that produces an acid that is weaker than the acid generated by the acid generator is indicated by the acid dissociation constant (pKa). The salt that generates an acid having a weaker acidity than the acid generated from the acid generator is a salt in which the pKa of the acid generated from the salt is usually -3 <pKa, preferably -1 <pKa <7. It is more preferably a salt of 0 <pKa <5. Examples of the salt that generates an acid weaker than the acid generated from the acid generator include salts represented by the following formulas, and JP-A-2012-229206, JP-A-2012-6908, and JP-A-2012-72109. , Japanese Patent Application Laid-Open No. 2011-39502 and Japanese Patent Application Laid-Open No. 2011-191745.

The content of the quencher (C) 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, based on the solid content of the resist composition. It is mass%.

<Other ingredients>
The resist composition of the present invention may contain components other than the above-mentioned components (hereinafter, may be referred to as "other components (F)"), if necessary. The other component (F) is not particularly limited, and additives known in the resist field, such as sensitizers, dissolution inhibitors, surfactants, stabilizers, dyes, and the like can be used.

<Preparation of resist composition>
The resist composition of the present invention comprises the resin (A) and the acid generator (B) of the present invention, and, if necessary, the resin (X), the quencher (C), the solvent (E) and other components ( It can be prepared by mixing F). The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can be 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). The mixing time can be selected from 0.5 to 24 hours depending on the mixing temperature. The mixing means is not particularly limited, and stirring and mixing or the like 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.

<Manufacturing method of resist pattern>
The method for producing a resist pattern of the present invention is
(1) A step of applying the resist composition of the present invention on a substrate,
(2) A step of drying the applied composition to form a composition layer,
(3) Step of exposing the composition layer,
It includes (4) a step of heating the composition layer after exposure and (5) a step of developing the composition layer after heating.

The resist composition can be applied onto the substrate by a commonly used device such as a spin coater. Examples of the substrate include an inorganic substrate such as a silicon wafer. The substrate may be washed before the resist composition is applied, or an antireflection film or the like may be formed on the substrate.

By drying the composition after coating, the solvent is removed and a composition layer is formed. Drying is performed, for example, by evaporating the solvent using a heating device such as a hot plate (so-called prebaking), or by using a decompression device. The heating temperature is preferably 50 to 200 ° C., and the heating time is preferably 10 to 180 seconds. The pressure at the time of vacuum drying is preferably about 1~1.0 × 10 ⁵ Pa.

The obtained composition layer is usually exposed to an exposure machine. The exposure machine may be an immersion exposure machine. The exposure light source includes a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), an F ₂ excimer laser (wavelength 157 nm) that emits laser light in the ultraviolet region, and a solid-state laser light source (YAG or semiconductor laser). Etc.), and various ones such as those that radiate high-frequency laser light in the far-ultraviolet region or vacuum ultraviolet region by wavelength conversion, those that irradiate electron beams, super-ultraviolet light (EUV), etc. are used. Can be done. In addition, in this specification, irradiating these radiations may be generically referred to as "exposure". At the time of exposure, the exposure is usually performed through a mask corresponding to the required pattern. When the exposure light source is an electron beam, the exposure may be performed by drawing directly without using a mask.

The exposed composition layer is heat treated (so-called post-exposure bake) to promote the deprotection reaction at the acid-labile group. The heating temperature is usually about 50 to 200 ° C, preferably about 70 to 150 ° C.

The composition layer after heating is usually developed using a developing solution using a developing device. Examples of the developing method include a dip method, a paddle method, a spray method, and a dynamic dispense method. The developing temperature is preferably 5 to 60 ° C., and the developing time is preferably 5 to 300 seconds. A positive resist pattern or a negative resist pattern can be produced by selecting the type of developer as follows.

When producing a positive resist pattern from the resist composition of the present invention, an alkaline developer is used as the developer. The alkaline developer may be any alkaline aqueous solution used in this field. For example, an aqueous solution of tetramethylammonium hydroxide or (2-hydroxyethyl) trimethylammonium hydroxide (commonly known as choline) can be mentioned. The alkaline developer may contain a surfactant.
After development, it is preferable to wash the resist pattern with ultrapure water and then remove the substrate and water remaining on the pattern.

When a negative resist pattern is produced from the resist composition of the present invention, a developer containing an organic solvent (hereinafter, may be referred to as "organic developer") is used as the developer.
Examples of the organic solvent contained in the organic developing solution include a ketone solvent such as 2-hexanone and 2-heptanone; a glycol ether ester solvent such as propylene glycol monomethyl ether acetate; an ester solvent such as butyl acetate; and a glycol such as propylene glycol monomethyl ether. Examples include ether solvents; amide solvents such as N and N-dimethylacetamide; aromatic hydrocarbon solvents such as anisole.
The content of the organic solvent in the organic developer is preferably 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less, and further preferably substantially only the organic solvent.
Among them, as the organic developer, a developer containing butyl acetate and / or 2-heptanone is preferable. The total content of butyl acetate and 2-heptanone in the organic developer is preferably 50% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and substantially butyl acetate and / or 2 -It is even more preferable that it is only heptanone.
The organic developer may contain a surfactant. Further, the organic developer may contain a small amount of water.
At the time of development, the development may be stopped by substituting with a solvent of a type different from that of the organic developer.

It is preferable to wash the developed resist pattern with a rinse solution. The rinsing 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, and an alcohol solvent or an ester solvent is preferable.
After cleaning, it is preferable to remove the rinse liquid remaining on the substrate and the pattern.

In the resist composition of the present invention, the resin (X) tends to have a high distribution on the surface in the composition layer, and elution of an acid generator or the like into an immersion exposure liquid during immersion exposure can be suppressed. .. In addition, the above-mentioned forward contact angle and backward contact angle caused by the resin (X) exhibit water repellency and enable high-speed scan exposure without leaving water droplets.

<Use>
The resist composition of the present invention includes a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) exposure, or a resist composition for EUV exposure, particularly ArF. It is suitable as a resist composition for excimer laser immersion exposure and is useful for fine processing of semiconductors.

The present invention will be described in more detail with reference to examples. In the examples, "%" and "part" representing the content or the amount used are based on mass unless otherwise specified.
The weight average molecular weight is a value obtained by gel permeation chromatography under the following conditions.
Equipment: HLC-8120GPC type (manufactured by Tosoh Corporation)
Column: TSKgel Multipore H _XL -M x 3 + guardcolumn (manufactured by Tosoh)
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)

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

式（Ｉ−２−ａ）で表される塩５部、式（Ｉ−２−ｂ）で表される化合物１．３部及びクロロホルム２５部を混合し、２３℃で３０分間攪拌した。得られた混合液に、二酢酸銅（ＩＩ）・一水和物０．０２部を添加した後、更に、６０℃で４時間還流攪拌し、濃縮した。得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル３５部を加えて、２３℃で３０分間攪拌した後、上澄み液を除去し、濃縮することにより、式（Ｉ−２−ｃ）で表される塩３．４部を得た。

式（Ｉ−２−ｄ）で表される塩４部、式（Ｉ−２−ｃ）で表される塩３．４部及びクロロホルム２０部を混合し、２３℃で２時間攪拌した。回収された反応物に、５％シュウ酸水１０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。回収された有機層に、イオン交換水１０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この水洗操作を５回繰り返した。回収された有機層をろ過した後、回収されたろ液を濃縮し、濃縮マスに、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌し、ろ過することにより、式（Ｉ−２）で表される塩４．０４部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６７．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ３３９．１ Example 1: Synthesis of salt represented by formula (I-2)

5 parts of the salt represented by the formula (I-2-a), 1.3 parts of the compound represented by the formula (I-2-b) and 25 parts of chloroform were mixed and stirred at 23 ° C. for 30 minutes. After adding 0.02 part of copper (II) diacetate and monohydrate to the obtained mixed solution, the mixture was further stirred under reflux at 60 ° C. for 4 hours to concentrate. 35 parts of tert-butyl methyl ether is added to the obtained residue, and the mixture is stirred at 23 ° C. for 30 minutes, and then the supernatant is removed and concentrated to obtain a salt represented by the formula (I-2-c). Obtained 3.4 copies.

4 parts of the salt represented by the formula (I-2-d), 3.4 parts of the salt represented by the formula (I-2-c) and 20 parts of chloroform were mixed and stirred at 23 ° C. for 2 hours. To the recovered reaction product, 10 parts of 5% oxalic acid water was added, and the mixture was stirred at 23 ° C. for 30 minutes, separated into liquids, and the organic layer was taken out. To the recovered organic layer, 10 parts of ion-exchanged water was added, the mixture was stirred at 23 ° C. for 30 minutes, and the liquid was separated to take out the organic layer. This washing operation was repeated 5 times. After filtering the recovered organic layer, the recovered filtrate is concentrated, 30 parts of tert-butyl methyl ether is added to the concentrated mass, stirred, and filtered, which is represented by the formula (I-2). 4.04 parts of salt was obtained.
MASS (ESI (+) Spectrum): M ⁺ 267.1
MASS (ESI (-) Spectrum): M ^- 339.1

式（Ｉ−２４−ａ）で表される塩５部、式（Ｉ−２−ｂ）で表される化合物１．１部及びクロロホルム２５部を混合し、２３℃で３０分間攪拌した。得られた混合液に、二酢酸銅（ＩＩ）・一水和物０．０１部を添加し、６０℃で１０時間還流攪拌した後、２３℃に冷却した。得られた反応物に、５％シュウ酸水１２．５部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。回収された有機層に、イオン交換水１２．５部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この水洗操作を５回繰り返した。回収された有機層をろ過した後、回収されたろ液を濃縮し、濃縮マスに、アセトニトリル１．０６部及びｔｅｒｔ−ブチルメチルエーテル３１．９２部を加えて、２３℃で３０分間攪拌した後、上澄み液を除去し、濃縮することにより、式（Ｉ−２４）で表される塩２．８３部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２１１．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ３３９．１ Example 2: Synthesis of salt represented by formula (I-24)

5 parts of the salt represented by the formula (I-24-a), 1.1 parts of the compound represented by the formula (I-2-b) and 25 parts of chloroform were mixed and stirred at 23 ° C. for 30 minutes. To the obtained mixed solution, 0.01 part of copper (II) diacetate and monohydrate was added, and the mixture was reflux-stirred at 60 ° C. for 10 hours and then cooled to 23 ° C. To the obtained reaction product, 12.5 parts of 5% oxalic acid water was added, and the mixture was stirred at 23 ° C. for 30 minutes, separated into liquids, and the organic layer was taken out. To the recovered organic layer, 12.5 parts of ion-exchanged water was added, the mixture was stirred at 23 ° C. for 30 minutes, and the liquid was separated to take out the organic layer. This washing operation was repeated 5 times. After filtering the recovered organic layer, the recovered filtrate is concentrated, 1.06 parts of acetonitrile and 31.92 parts of tert-butyl methyl ether are added to the concentrated mass, and the mixture is stirred at 23 ° C. for 30 minutes. The supernatant was removed and concentrated to give 2.83 parts of salt represented by the formula (I-24).
MASS (ESI (+) Spectrum): M ⁺ 211.1
MASS (ESI (-) Spectrum): M ^- 339.1

式（Ｉ−３−ｄ）で表される塩３．９部、式（Ｉ−２−ｃ）で表される塩３．４部及びクロロホルム２０部を混合し、２３℃で２時間攪拌した。回収された反応物に、５％シュウ酸水１０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。回収された有機層に、イオン交換水１０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この水洗操作を５回繰り返した。回収された有機層をろ過した後、回収されたろ液を濃縮し、濃縮マスに、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌し、ろ過することにより、式（Ｉ−３）で表される塩４．２８部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２６７．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ３２３．０ Example 3: Synthesis of salt represented by formula (I-3)

3.9 parts of the salt represented by the formula (I-3-d), 3.4 parts of the salt represented by the formula (I-2-c) and 20 parts of chloroform were mixed and stirred at 23 ° C. for 2 hours. .. To the recovered reaction product, 10 parts of 5% oxalic acid water was added, and the mixture was stirred at 23 ° C. for 30 minutes, separated into liquids, and the organic layer was taken out. To the recovered organic layer, 10 parts of ion-exchanged water was added, the mixture was stirred at 23 ° C. for 30 minutes, and the liquid was separated to take out the organic layer. This washing operation was repeated 5 times. After filtering the recovered organic layer, the recovered filtrate is concentrated, 30 parts of tert-butyl methyl ether is added to the concentrated mass, and the mixture is stirred and filtered to be represented by the formula (I-3). 4.28 parts of salt was obtained.
MASS (ESI (+) Spectrum): M ⁺ 267.1
MASS (ESI (-) Spectrum): M ^- 323.0

式（Ｉ−１３４−ａ）で表される塩４．２部、式（Ｉ−２−ｂ）で表される化合物１．３部及びクロロホルム２５部を混合し、２３℃で３０分間攪拌した。得られた混合液に、二酢酸銅（ＩＩ）・一水和物０．０２部を添加した後、更に、６０℃で４時間還流攪拌し、濃縮した。得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル３５部を加えて、２３℃で３０分間攪拌した後、上澄み液を除去し、濃縮することにより、式（Ｉ−１３４−ｃ）で表される塩３．２部を得た。

式（Ｉ−２−ｄ）で表される塩４部、式（Ｉ−１３４−ｃ）で表される塩３．０部及びクロロホルム２０部を混合し、２３℃で２時間攪拌した。回収された反応物に、５％シュウ酸水１０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。回収された有機層に、イオン交換水１０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この水洗操作を５回繰り返した。回収された有機層をろ過した後、回収されたろ液を濃縮し、濃縮マスに、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌し、ろ過することにより、式（Ｉ−１３４）で表される塩３．５６部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２２７．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ３３９．１ Example 4: Synthesis of salt represented by formula (I-134)

4.2 parts of the salt represented by the formula (I-134-a), 1.3 parts of the compound represented by the formula (I-2-b) and 25 parts of chloroform were mixed and stirred at 23 ° C. for 30 minutes. .. After adding 0.02 part of copper (II) diacetate and monohydrate to the obtained mixed solution, the mixture was further stirred under reflux at 60 ° C. for 4 hours to concentrate. 35 parts of tert-butyl methyl ether is added to the obtained residue, and the mixture is stirred at 23 ° C. for 30 minutes, and then the supernatant is removed and concentrated to obtain a salt represented by the formula (I-134-c). 3.2 copies were obtained.

4 parts of the salt represented by the formula (I-2-d), 3.0 parts of the salt represented by the formula (I-134-c) and 20 parts of chloroform were mixed and stirred at 23 ° C. for 2 hours. To the recovered reaction product, 10 parts of 5% oxalic acid water was added, and the mixture was stirred at 23 ° C. for 30 minutes, separated into liquids, and the organic layer was taken out. To the recovered organic layer, 10 parts of ion-exchanged water was added, the mixture was stirred at 23 ° C. for 30 minutes, and the liquid was separated to take out the organic layer. This washing operation was repeated 5 times. After filtering the recovered organic layer, the recovered filtrate is concentrated, 30 parts of tert-butyl methyl ether is added to the concentrated mass, and the mixture is stirred and filtered to be represented by the formula (I-134). 3.56 parts of salt was obtained.
MASS (ESI (+) Spectrum): M ⁺ 227.1
MASS (ESI (-) Spectrum): M ^- 339.1

式（Ｉ−３−ｄ）で表される塩３．９部、式（Ｉ−１３４−ｃ）で表される塩３．０部及びクロロホルム２０部を混合し、２３℃で２時間攪拌した。回収された反応物に、５％シュウ酸水１０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。回収された有機層に、イオン交換水１０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この水洗操作を５回繰り返した。回収された有機層をろ過した後、回収されたろ液を濃縮し、濃縮マスに、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌し、ろ過することにより、式（Ｉ−１３５）で表される塩３．７２部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２２７．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ３２３．０ Example 5: Synthesis of salt represented by formula (I-135)

3.9 parts of the salt represented by the formula (I-3-d), 3.0 parts of the salt represented by the formula (I-134-c) and 20 parts of chloroform were mixed and stirred at 23 ° C. for 2 hours. .. To the recovered reaction product, 10 parts of 5% oxalic acid water was added, and the mixture was stirred at 23 ° C. for 30 minutes, separated into liquids, and the organic layer was taken out. To the recovered organic layer, 10 parts of ion-exchanged water was added, the mixture was stirred at 23 ° C. for 30 minutes, and the liquid was separated to take out the organic layer. This washing operation was repeated 5 times. After filtering the recovered organic layer, the recovered filtrate is concentrated, 30 parts of tert-butyl methyl ether is added to the concentrated mass, and the mixture is stirred and filtered to be represented by the formula (I-135). 3.72 parts of salt was obtained.
MASS (ESI (+) Spectrum): M ⁺ 227.1
MASS (ESI (-) Spectrum): M ^- 323.0

式（Ｉ−１５６−ａ）で表される塩４．５部、式（Ｉ−２−ｂ）で表される化合物１．３部及びクロロホルム２５部を混合し、２３℃で３０分間攪拌した。得られた混合液に、二酢酸銅（ＩＩ）・一水和物０．０２部を添加した後、更に、６０℃で４時間還流攪拌し、濃縮した。得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル３５部を加えて、２３℃で３０分間攪拌した後、上澄み液を除去し、濃縮することにより、式（Ｉ−１５６−ｃ）で表される塩３．６部を得た。

式（Ｉ−２−ｄ）で表される塩４部、式（Ｉ−１５６−ｃ）で表される塩３．１部及びクロロホルム２０部を混合し、２３℃で２時間攪拌した。回収された反応物に、５％シュウ酸水１０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。回収された有機層に、イオン交換水１０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この水洗操作を５回繰り返した。回収された有機層をろ過した後、回収されたろ液を濃縮し、濃縮マスに、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌し、ろ過することにより、式（Ｉ−１５６）で表される塩３．９２部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２４１．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ３３９．１ Example 6: Synthesis of salt represented by formula (I-156)

4.5 parts of the salt represented by the formula (I-156-a), 1.3 parts of the compound represented by the formula (I-2-b) and 25 parts of chloroform were mixed and stirred at 23 ° C. for 30 minutes. .. After adding 0.02 part of copper (II) diacetate and monohydrate to the obtained mixed solution, the mixture was further stirred under reflux at 60 ° C. for 4 hours to concentrate. 35 parts of tert-butyl methyl ether is added to the obtained residue, and the mixture is stirred at 23 ° C. for 30 minutes, and then the supernatant is removed and concentrated to obtain a salt represented by the formula (I-156-c). 3.6 copies were obtained.

4 parts of the salt represented by the formula (I-2-d), 3.1 parts of the salt represented by the formula (I-156-c) and 20 parts of chloroform were mixed and stirred at 23 ° C. for 2 hours. To the recovered reaction product, 10 parts of 5% oxalic acid water was added, and the mixture was stirred at 23 ° C. for 30 minutes, separated into liquids, and the organic layer was taken out. To the recovered organic layer, 10 parts of ion-exchanged water was added, the mixture was stirred at 23 ° C. for 30 minutes, and the liquid was separated to take out the organic layer. This washing operation was repeated 5 times. After filtering the recovered organic layer, the recovered filtrate is concentrated, 30 parts of tert-butyl methyl ether is added to the concentrated mass, stirred, and filtered, which is represented by the formula (I-156). 3.92 parts of salt was obtained.
MASS (ESI (+) Spectrum): M ⁺ 241.1
MASS (ESI (-) Spectrum): M ^- 339.1

式（Ｉ−３−ｄ）で表される塩３．９部、式（Ｉ−１５６−ｃ）で表される塩３．１部及びクロロホルム２０部を混合し、２３℃で２時間攪拌した。回収された反応物に、５％シュウ酸水１０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。回収された有機層に、イオン交換水１０部を加えて２３℃で３０分間攪拌し、分液して有機層を取り出した。この水洗操作を５回繰り返した。回収された有機層をろ過した後、回収されたろ液を濃縮し、濃縮マスに、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌し、ろ過することにより、式（Ｉ−１５７）で表される塩４．２２部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２４１．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ３２３．０ Example 7: Synthesis of salt represented by formula (I-157)

3.9 parts of the salt represented by the formula (I-3-d), 3.1 parts of the salt represented by the formula (I-156-c) and 20 parts of chloroform were mixed and stirred at 23 ° C. for 2 hours. .. To the recovered reaction product, 10 parts of 5% oxalic acid water was added, and the mixture was stirred at 23 ° C. for 30 minutes, separated into liquids, and the organic layer was taken out. To the recovered organic layer, 10 parts of ion-exchanged water was added, the mixture was stirred at 23 ° C. for 30 minutes, and the liquid was separated to take out the organic layer. This washing operation was repeated 5 times. After filtering the recovered organic layer, the recovered filtrate is concentrated, 30 parts of tert-butyl methyl ether is added to the concentrated mass, and the mixture is stirred and filtered to be represented by the formula (I-157). 4.22 parts of salt was obtained.
MASS (ESI (+) Spectrum): M ⁺ 241.1
MASS (ESI (-) Spectrum): M ^- 323.0

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

Synthesis Example 1 [Synthesis of resin A1]
As the monomer, a monomer (a1-1-3), a monomer (a1-2-11), a monomer (a1-0-1), a monomer (a2-1-1) and a monomer (a3-4-2) are used. The molar ratio [monomer (a1-1-3): monomer (a1-2-11): monomer (a1-0-1): monomer (a2-1-1): monomer (a3-4-2)] The mixture was mixed so as to be 15:25:10: 3:47, and propylene glycol monomethyl ether acetate 1.5% by mass of the total amount of monomers was added to prepare a solution. To this solution, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in an amount of 1 mol% and 3 mol%, respectively, based on the total amount of monomers, and these were heated at 75 ° C. for about 5 hours. bottom. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate a resin, and the resin was filtered. The obtained resin is dissolved again in propylene glycol monomethyl ether acetate, and the obtained solution is poured into a mixed solvent of methanol / water to precipitate the resin, and the resin is filtered. resin A1 of molecular weight 7.9 × 10 ³ (copolymer) was obtained in 78% yield. This resin A1 has the following structural units.

Synthesis Example 2 [Synthesis of resin A2]
As the monomer, a monomer (a1-1-3), a monomer (a1-2-9), a monomer (a2-1-1) and a monomer (a3-4-2) are used, and the molar ratio [monomer (a1-1-1)] is used. -3): Monomer (a1-2-9): Monomer (a2-1-1): Monomer (a3-4-2)] are mixed so as to be 35: 15: 2.5: 47.5. A propylene glycol monomethyl ether acetate 1.5% by mass of the total amount of monomers was added to prepare a solution. To this solution, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in an amount of 1 mol% and 3 mol%, respectively, based on the total amount of monomers, and these were heated at 75 ° C. for about 5 hours. bottom. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate a resin, and the resin was filtered. The resulting resin was added to a methanol / water mixed solvent, after repulping, performed twice a purification operation that filtered to give the resin A2 having a weight-average molecular weight 8.0 × 10 ³ in 69% yield. This resin A2 has the following structural units.

Synthesis Example 3 [Synthesis of resin A3]
As the monomer, a monomer (a1-1-3), a monomer (a1-2-11), a monomer (a2-1-1) and a monomer (a3-4-2) are used, and the molar ratio [monomer (a1-1-1)] is used. -3): Monomer (a1-2-11): Monomer (a2-1-1): Monomer (a3-4-2)] are mixed so as to be 35: 15: 2.5: 47.5. A propylene glycol monomethyl ether acetate 1.5% by mass of the total amount of monomers was added to prepare a solution. To this solution, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in an amount of 1 mol% and 3 mol%, respectively, based on the total amount of monomers, and these were heated at 75 ° C. for about 5 hours. bottom. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate a resin, and the resin was filtered. The resulting resin was added to a methanol / water mixed solvent, after repulping, performed twice a purification operation of filtration, to obtain a resin A3 having a weight-average molecular weight 7.9 × 10 ³ in 65% yield. This resin A3 has the following structural units.

Synthesis Example 4 [Synthesis of resin X1]
As the monomer, a monomer (a5-1-1) and a monomer (a4-0-12) are used, and the molar ratio [monomer (a5-1-1): monomer (a4-0-12)] is 50:50. Methyl isobutyl ketone was added in an amount 1.2% by mass of the total amount of the monomers to prepare a solution. Azobis (2,4-dimethylvaleronitrile) as an initiator was added to this solution in an amount of 3 mol% based on the total amount of monomers, and the mixture was heated at 70 ° C. for about 5 hours. The reaction mixture obtained, the resin was precipitated by pouring into a large amount of methanol / water mixed solvent, the resin was filtered, the weight-average molecular weight 1.0 × 10 ⁴ of the resin X1 (copolymer) to yield 91% I got it in. This resin X1 has the following structural units.

(Preparation of resist composition)
Each of the components shown below was mixed by the mass part shown in Table 7 and dissolved in a solvent, and then filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

Ｂ１−Ｘ１：式（Ｂ１−Ｘ１）で表される塩（特開２００８−２４６７１号公報の実施例に従って合成）
Ｂ１−２：式（Ｂ１−２）で表される塩（特開２００６−２５７０７８号公報を参考にして合成）

＜クエンチャー（Ｃ）＞
Ｄ１：（東京化成工業（株）製）

＜溶剤＞
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 <Resin>
A1 to A3, X1: Resin A1 to Resin A3, Resin X1
<Salt (I)>
I-2: Salt represented by formula (I-2) I-3: Salt represented by formula (I-3) I-24: Salt represented by formula (I-24) I-134: Salt represented by formula (I-24) Salt represented by (I-134) I-135: Salt represented by formula (I-135) I-156: Salt represented by formula (I-156) I-157: Salt represented by formula (I-157) Salt represented by <acid generator (B)>
B1-21: A salt represented by the formula (B1-21) (synthesized according to an example of JP2012-224611).
B1-22: Salt represented by the formula (B1-22) (synthesized according to an example of JP2012-224611)

B1-X1: A salt represented by the formula (B1-X1) (synthesized according to an example of JP-A-2008-24671).
B1-2: Salt represented by the formula (B1-2) (synthesized with reference to JP-A-2006-257078)

<Quencher (C)>
D1: (manufactured by Tokyo Chemical Industry Co., Ltd.)

<Solvent>
Propylene Glycol Monomethyl Ether Acetate 265 Parts Propylene Glycol Monomethyl Ether 20 Parts 2-Heptanone 20 Parts γ-Butyrolactone 3.5 Parts

<Manufacturing of resist pattern and its evaluation>
An organic antireflection film composition (ARC-29; manufactured by Nissan Chemical Industries, Ltd.) is applied to a silicon wafer and baked at 205 ° C. for 60 seconds to produce organic reflection on the wafer with a film thickness of 78 nm. An anti-reflective film was formed. Next, the above resist composition was applied (spin coated) on the organic antireflection film so that the film thickness after drying was 85 nm. After coating, the silicon wafer was prebaked on a direct hot plate at the temperature listed in the “PB” column of Table 7 for 60 seconds to form a composition layer. A contact hole pattern (hole pitch 90 nm) was used on a silicon wafer on which a composition layer was formed with an ArF excimer stepper for immersion exposure (XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Anal XY polarization). / Using a mask for forming a hole diameter of 55 nm), the exposure amount was changed stepwise for exposure. Ultrapure water was used as the immersion medium.
After the exposure, post-exposure baking was performed on a hot plate at the temperature listed in the “PEB” column of Table 7 for 60 seconds. Next, the composition layer on the silicon wafer was developed by the dynamic dispensing method at 23 ° C. for 20 seconds using butyl acetate (manufactured by Tokyo Chemical Industry Co., Ltd.) as a developing solution to form a negative resist pattern. Manufactured.

In the resist pattern obtained after development, the exposure amount at which the hole diameter formed by using the mask was 45 nm was defined as the effective sensitivity.

<Mask error factor (MEF) evaluation>
In terms of effective sensitivity, a resist pattern was formed using masks having mask hole diameters (hole diameters of translucent portions of the mask) of 57 nm, 56 nm, 55 nm, 54 nm, and 53 nm (hole pitches are all 90 nm), respectively. The slope of the regression line when the hole diameter of the resist pattern formed (transferred) on the substrate by exposure was plotted on the vertical axis with the mask hole diameter on the horizontal axis was calculated as the MEF value.
Those with a MEF value of 4.7 or less are evaluated as having a good MEF, and are marked with ○.
Those having a MEF value exceeding 4.7 were evaluated as having poor MEF and were evaluated as x.
The results are shown in Table 8. The numbers in parentheses indicate the MEF value.

The resist composition containing the salt of the present invention is suitable for microfabrication of semiconductors because a resist pattern can be produced with a good mask error factor (MEF).

Claims (7)

An acid generator containing a first salt and a second salt represented by the formula (I), respectively .

[In formula (I),
R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ and R ¹¹ each independently have a hydrogen atom, a hydroxy group or 1 to 12 carbon atoms. Representing a hydrocarbon group, −CH ₂₋ contained in the hydrocarbon group may be replaced with −O− or −CO−.
n represents 1.
Q ¹ and ^{Q 2} each independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms.
L ^b1 is a divalent saturated hydrocarbon group having 2 or 3 carbon atoms in which two −CH ₂₋ are replaced with −CO− and −O− to form an ester, respectively.
Y of the first salt is an adamantyl group which may have a hydroxy group.
Y of the second salt is an adamantyl group in which one of _{−CH 2−} is substituted with −O−. ] The acid generator according to claim 1, wherein R ³ is an alkyl group having 1 to 8 carbon atoms. A resist composition containing the acid generator according to claim 1 or 2 and a resin having an acid unstable group. The resist composition according to claim 3 , wherein the resin further contains a structural unit having a lactone ring. The resist composition according to claim 3 or 4 , further containing a salt that generates an acid having a weaker acidity than the acid generated from the acid generator. The resist composition according to any one of claims 3 to 5 , further comprising a resin containing a structural unit having a fluorine atom. (1) A step of applying the resist composition according to any one of claims 3 to 6 onto a substrate.
(2) A step of drying the applied composition to form a composition layer,
(3) Step of 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,
A method for producing a resist pattern including.