JP6913544B2 - Method for manufacturing resist 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.

JP-A-2002-268223

In the conventional resist composition, the line edge roughness at the time of producing the resist pattern is not always satisfactory.

［式（Ｉ）中、
Ａｒ^１及びＡｒ^２は、それぞれ独立に、置換基を有していてもよい炭素数６〜３６の芳香族炭化水素基又は置換基を有していてもよい炭素数４〜３６のヘテロ芳香族炭化水素基を表す。
Ｘ^１及びＸ^２は、それぞれ独立に、炭素数１〜６のアルカンジイル基を表す。
Ｒ^１は、置換基を有してもよい炭素数１〜１８の炭化水素基を表す。
Ｒ^５及びＲ^６は、それぞれ独立に、フッ素原子を有する炭素数１〜４のアルキル基を表すか、互いに結合してフッ素原子を有する炭素数２〜８の２価の複素環を形成する。］
〔２〕Ａｒ^１及びＡｒ^２が、共に、置換基を有していてもよいフェニル基である〔１〕記載の塩。
〔３〕Ｘ^１及びＸ^２が、共に、メチレン基である〔１〕又は〔２〕記載の塩。
〔４〕〔１〕〜〔３〕のいずれかに記載の塩を含む酸発生剤。
〔５〕〔４〕に記載の酸発生剤と酸不安定基を有する構造単位を含む樹脂とを含有するレジスト組成物。
〔６〕酸不安定基を有する構造単位を含む樹脂が、さらに、ラクトン環を有する構造単位を含む〔５〕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〕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る〔５〕〜〔７〕のいずれか記載のレジスト組成物。
〔９〕（１）〔５〕〜〔８〕のいずれか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),
Ar ¹ and Ar ² are independently aromatic hydrocarbon groups having 6 to 36 carbon atoms which may have substituents or heteroaromatics having 4 to 36 carbon atoms which may have substituents. Represents a hydrocarbon group.
X ¹ and X ² each independently represent an alkanediyl group having 1 to 6 carbon atoms.
R ¹ represents a hydrocarbon group having 1 to 18 carbon atoms which may have a substituent.
R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 4 carbon atoms having a fluorine atom, or bond with each other to form a divalent heterocycle having 2 to 8 carbon atoms having a fluorine atom. ]
[2] The salt according to [1], wherein both ^{Ar 1} and Ar ^{2 are phenyl groups which may have a substituent.}
[3] The salt according to [1] or [2], wherein both ^{X 1} and X ^{2 are methylene groups.}
[4] An acid generator containing the salt according to any one of [1] to [3].
[5] A resist composition containing the acid generator according to [4] and a resin containing a structural unit having an acid unstable group.
[6] The resist composition according to [5], wherein the resin containing a structural unit having an acid unstable group 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,
A method for producing a resist pattern, which comprises a step of (4) heating the composition layer after exposure and (5) a step of developing the composition layer after heating.

By using the resist composition of the present invention, a resist pattern having good line edge roughness can be produced.

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.
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.

［式（Ｉ）中、
Ａｒ^１及びＡｒ^２は、それぞれ独立に、置換基を有していてもよい炭素数６〜３６の芳香族炭化水素基又は置換基を有していてもよい炭素数４〜３６のヘテロ芳香族炭化水素基を表す。
Ｘ^１及びＸ^２は、それぞれ独立に、炭素数１〜６のアルカンジイル基を表す。
Ｒ^１は、置換基を有してもよい炭素数１〜１８の炭化水素基を表す。
Ｒ^５及びＲ^６は、それぞれ独立に、フッ素原子を有する炭素数１〜４のアルキル基を表すか、互いに結合してフッ素原子を有する炭素数２〜８の２価の複素環を形成する。］ <Salt (I)>
The present invention relates to a salt represented by the formula (I) (hereinafter, may be referred to as a salt (I)).

[In formula (I),
Ar ¹ and Ar ² are independently aromatic hydrocarbon groups having 6 to 36 carbon atoms which may have substituents or heteroaromatics having 4 to 36 carbon atoms which may have substituents. Represents a hydrocarbon group.
X ¹ and X ² each independently represent an alkanediyl group having 1 to 6 carbon atoms.
R ¹ represents a hydrocarbon group having 1 to 18 carbon atoms which may have a substituent.
R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 4 carbon atoms having a fluorine atom, or bond with each other to form a divalent heterocycle having 2 to 8 carbon atoms having a fluorine atom. ]

The aromatic hydrocarbon groups of Ar ¹ and Ar ² include a phenyl group, a naphthyl group, an anthryl group, a phenanthonyl group, a trill group, a xsilyl group, a cumyl group, a dimethylphenyl group, a trimethylphenyl group, an ethylphenyl group and a propylphenyl group. , Butylphenyl group, biphenyl group, triphenyl group, indenyl group, tetrahydronaphthyl group, p-adamantylphenyl group, phenanthryl group, 2,6-diethylphenyl group, 2-methyl-6-ethylphenyl group, etc. Included are ~ 36 aryl groups.
Examples of the hetero atom include a nitrogen atom, an oxygen atom, and a sulfur atom.
Examples of the heteroaromatic hydrocarbon group include heteroaromatic hydrocarbon groups having 4 to 36 carbon atoms such as a frill group and a thiophenyl group.
The ^{aromatic hydrocarbon group represented by Ar 1} and Ar ² preferably has 6 to 24 carbon atoms, and more preferably 6 to 18 carbon atoms.
The ^{heteroaromatic hydrocarbon group represented by Ar 1} and Ar ² preferably has 4 to 24 carbon atoms, and more preferably 4 to 18 carbon atoms.
The ^{aromatic hydrocarbon group represented by Ar 1} and Ar ² or the heteroaromatic hydrocarbon may have a substituent. Examples of the substituent include a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alkylcarbonyloxy group having 2 to 18 carbon atoms, an arylcarbonyloxy group having 7 to 18 carbon atoms or an alkoxycarbonyloxy group having 2 to 18 carbon atoms. _{The −CH 2−} contained in the alkoxy group having 1 to 12 carbon atoms may be replaced with −O−. It is preferably a hydroxy 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, and preferably have 1 to 1 carbon atoms. It is an alkoxy group of 6, more preferably a methoxy group.
Examples of the alkylcarbonyloxy group include methylcarbonyloxy group, ethylcarbonyloxy group, n-propylcarbonyloxy group, isopropylcarbonyloxy group, n-butylcarbonyloxy group, sec-butylcarbonyloxy group, tert-butylcarbonyloxy group, and the like. Examples thereof include a pentylcarbonyloxy group, a hexylcarbonyloxy group, an octylcarbonyloxy group and a 2-ethylhexylcarbonyloxy group, preferably an alkylcarbonyloxy group having 2 to 12 carbon atoms, and more preferably a methylcarbonyloxy group. ..
Examples of the arylcarbonyloxy group include a phenylcarbonyloxy group and a tosylcarbonyloxy group, preferably an arylcarbonyloxy group having 7 to 12 carbon atoms, and more preferably a phenylcarbonyloxy group.
The alkoxycarbonyloxy group includes methoxycarbonyloxy group, ethoxycarbonyloxy group, n-propoxycarbonyloxy group, isopropoxycarbonyloxy group, n-butoxycarbonyloxy group, sec-butoxycarbonyloxy group, tert-butoxycarbonyloxy group. , Pentyloxycarbonyloxy group, hexyloxycarbonyloxy group, octyloxycarbonyloxy group, 2-ethylhexyloxycarbonyloxy group and the like, preferably an alkyloxycarbonyloxy group having 2 to 8 carbon atoms, more preferably. It is a tert-butyloxycarbonyloxy group.

Examples of the alkanediyl group of X ¹ and X ² include a linear alkanediyl group and a branched alkanediyl group.
Specifically, linear chains such as 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. Alkanediyl group, ethane-1,1-diyl group, propane-1,1-diyl group, propane-1,2-diyl group, propane-2,2-diyl group, pentane-2,4-diyl group, A branched alkanediyl group such as 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2-diyl group, pentane-1,4-diyl group, 2-methylbutane-1,4-diyl group. And so on.

Examples of the hydrocarbon group having 1 to 18 carbon atoms of R ¹ include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these.
The alkyl 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, a heptyl group, a 2-ethylhexyl group and an 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 group 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.
Examples of the substituent include a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an alkylcarbonyloxy group having 2 to 18 carbon atoms, an arylcarbonyloxy group having 7 to 18 carbon atoms or an alkoxycarbonyloxy group having 2 to 18 carbon atoms. _{The −CH 2−} contained in the alkoxy group having 1 to 12 carbon atoms may be replaced with −O−. It is preferably a hydroxy group.
Examples of these substituents are the same as those exemplified ^{in Ar 1} and Ar ^2.

Examples of the alkyl group having 1 to 4 carbon atoms having the fluorine atoms of R ⁵ and R ⁶ include a difluoromethyl group, a trifluoromethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, and 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, perfluoropropyl group, 1,1,2,2-tetrafluorobutyl group, 1,1,2,2,3,3-hexafluoro Butyl group, 1,1,2,2,3,3,4,5-octafluorobutyl group, perfluorobutyl group, 1,1-bis (trifluoro) methyl-2,2,2-trifluoroethyl group, etc. Of these, perfluoroalkyl groups are preferable, trifluoromethyl groups and perfluoroethyl groups are more preferable, and trifluoromethyl groups are even more preferable.

When R ⁵ and R ⁶ are bonded to each other to form a divalent heterocycle having 2 to 8 carbon atoms having a fluorine atom, R ⁵ and R ⁶ are, for example, a perfluoromethylene group, a perfluoroethylene group, and a perfluoropropanediyl. Examples thereof include a perfluoroalkandyl group such as a group, a perfluorobutandyl group, a perfluoropentandyl group and a perfluorohexanediyl group. Of these, a 5-membered or 6-membered heterocycle is preferable.

Examples of the cation of the salt (I) include cations represented by the following formulas (I-c-1) to (I-c-20).

なかでも、式（Ｉ−ｃ−１）〜式（Ｉ−ｃ−１２）で表されるカチオンが好ましく、式（Ｉ−ｃ−１）〜式（Ｉ−ｃ−１０）で表されるカチオンがより好ましく、式（Ｉ−ｃ−１）〜式（Ｉ−ｃ−６）で表されるカチオンがより好ましい。

Of these, the cations represented by the formulas (I-c-1) to (I-c-12) are preferable, and the cations represented by the formulas (I-c-1) to (I-c-10) are preferable. Is more preferable, and cations represented by the formulas (I-c-1) to (I-c-6) are more preferable.

Examples of the anion of the salt (I) include the following anions.

As the salt (I), the above-mentioned cations and anions can be arbitrarily combined.
Among them, the following are mentioned as preferable salt (I).

［式中、全ての符号は、それぞれ前記と同じ意味を表す。］
溶剤としては、クロロホルム、イオン交換水等が挙げられる。
式（ＩＡ１−ｂ）で表される塩は、例えば、以下で表される塩などが挙げられ、市場から容易に入手できる。

<Manufacturing method of salt (I)>
The salt (I) can be produced, for example, by reacting a salt represented by the formula (IA1-a) with a compound represented by the formula (IA1-b) in a solvent.

[In the formula, all the symbols have the same meanings as described above. ]
Examples of the solvent include chloroform, ion-exchanged water and the like.
Examples of the salt represented by the formula (IA1-b) include salts represented by the following, which are easily available on the market.

溶剤としては、クロロホルム、ジムロロメタン、イオン交換水等が挙げられる。
式（ＩＡ１−ｃ）で表される化合物は、例えば、下記式で表される塩などが挙げられ、これらは市場から容易に入手できる。

式（ＩＡ１−ｄ）で表される化合物は、例えば、ヨウ化メチルなどが挙げられ、これらは市場から容易に入手できる。 The salt represented by the formula (IA1-a) is a reaction of a compound represented by the formula (IA1-c) and a compound represented by the formula (IA1-d) in a solvent in the presence of silver methyl sulfate. It can be manufactured by allowing it to be produced.

Examples of the solvent include chloroform, dimlolomethane, ion-exchanged water and the like.
Examples of the compound represented by the formula (IA1-c) include salts represented by the following formulas, which are easily available on the market.

Examples of the compound represented by the formula (IA1-d) include methyl iodide, which are easily available on the market.

<Acid generator containing salt (I)>
The acid generator of the present invention is an acid generator containing a salt (I). In the acid generator, the salt (I) may be used alone or in combination of two or more.
In addition to the salt (I), the acid generator of the present invention may contain an acid generator known in the field of resist (hereinafter, may be referred to as “acid generator (B)”). The acid generator (B) will be described later.
When the salt (I) and the acid generator (B) are contained as the acid generator, the ratio of the contents of the salt (I) and the acid generator (B) (mass ratio, salt (I): acid generator (B)) is usually 1:99 to 99: 1, preferably 2:98 to 98: 2, and more preferably 5:95 to 95: 5.

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

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 the formulas (B1-1) to (B1-48), among which the formulas (B1-1) to the formulas (B1-3) containing an arylsulfonium cation and the formulas (B1-3). B1-5) to formula (B1-7), formula (B1-11) to formula (B1-14), formula (B1-17), formula (B1-20) 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.

[Resist composition]
The resist composition of the present invention
It contains an acid generator containing a salt (I) and a resin containing a structural unit having an acid unstable group (hereinafter, may be referred to as "resin (A)").
In addition to the salt (I) and the resin (A), the resist composition of the present invention further contains a resin other than the resin (A), for example, a resin containing a structural unit having a fluorine atom (hereinafter, "resin (X)). ”), Quenchers (hereinafter sometimes referred to as“ Quencher (C) ”) and / or solvents (hereinafter sometimes referred to as“ solvent (E) ”) are preferably contained.

<Resin (A)>
The resin (A) has a structural unit 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). As the structural unit other than the structural unit (a1), a structural unit having no acid-labile group (hereinafter, may be referred to as “structural unit (s)”) and other structural units (hereinafter, “structural unit (t)””. ) And 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み合わせた基を表すか、Ｒ^a1及びＲ^a2は互いに結合してそれらが結合する炭素原子とともに炭素数３〜２０の２価の脂環式炭化水素基を形成する。
ｎａは、０又は１を表す。
＊は結合手を表す。］

［式（２）中、Ｒ^a1’及びＲ^a2’は、それぞれ独立に、水素原子又は炭素数１〜１２の炭化水素基を表し、Ｒ^a3’は、炭素数１〜２０の炭化水素基を表すか、Ｒ^a2’及びＲ^a3’は互いに結合してそれらが結合する炭素原子とともに炭素数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メチレン基は、酸素原子又は硫黄原子で置き換わってもよい。
Ｘは、酸素原子又は硫黄原子を表す。
＊は結合手を表す。］ <Structural unit (a1)>
The structural unit (a1) is derived from a monomer having an acid unstable group (hereinafter, may be referred to as “monomer (a1)”).
In the resin (A), the acid unstable group contained in the structural unit (a1) is preferably a group represented by the following 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 R ^a2 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. ]

[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 to which they are bonded, and the hydrocarbon group and the divalent heterocyclic group. The methylene group contained in may be replaced with an oxygen atom or a sulfur atom.
X represents an oxygen atom or a sulfur atom.
* Represents a bond. ]

アルキル基と脂環式炭化水素基とを組み合わせた基としては、メチルシクロヘキシル基、ジメチルシクロへキシル基、メチルノルボルニル基、シクロヘキシルメチル基、アダマンチルメチル基、アダマンチルジメチル基、ノルボルニルエチル基等が挙げられる。
ｎａは、好ましくは０である。 ^Examples of 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 have preferably 3 to 16 carbon atoms.

Examples of the group combining the alkyl group and the alicyclic hydrocarbon group include a methylcyclohexyl group, a dimethylcyclohexyl group, a methylnorbornyl group, a cyclohexylmethyl group, an adamantylmethyl group, an adamantyldimethyl group, and a norbornylethyl group. And so on.
na is preferably 0.

^{Examples of -C (R a1} ) (R ^a2 ) (R ^a3 ) in the case where R ^a1 and R a ² 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) include a 1,1-dialkylalkoxycarbonyl group (a group in which R ^{a1 to} R ^a3 are alkyl groups in the formula (1), preferably a tert-butoxycarbonyl group), 2-. Alkyl adamantan-2-yloxycarbonyl group (in formula (1), R ^a1 , R ^a2 and the carbon atom to which they are bonded form an adamantyl group, and R ^a3 is an alkyl group) and 1- (adamantan-). 1-yl) -1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are alkyl groups and R ^a3 is an adamantyl group) and the like.

Ｒ^a1'及びＲ^a2'のうち、少なくとも１つは水素原子であることが好ましい。 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.
The aromatic hydrocarbon group includes 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 a resin (A) having a structural unit derived from a 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）中、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み合わ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 structural unit (a1). -0), structural unit (a1-1) and structural unit (a1-2).

[In the formula (a1-0), in 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 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 preferably oxygen atom or _{* -O- (CH 2) k01 -CO} -O- and is (however, k01 is preferably either 1 to 4 integer, more preferably Is 1.), More preferably an oxygen atom.
R ^a4 and R ^a5 are preferably methyl groups.
The alkyl groups of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 , the alicyclic hydrocarbon group and the group combining these are the same as the groups listed in ^{R a1 to} R ^{a3 of the formula (1).} The group is mentioned.
The alkyl group of R ^a02 , R ^a03 and R ^a04 preferably has 1 to 6 carbon atoms, and more preferably a methyl group or an ethyl group.
The ^{number of carbon atoms of the alkyl group in R a6} and R ^a7 is preferably 1 to 6, more preferably a methyl group, an ethyl group or an isopropyl group, and further preferably an ethyl group or an isopropyl group.
The alicyclic hydrocarbon groups of R ^a02 , R ^a03 , R ^a04 , R ^a6 and R ^a7 have preferably 5 to 12 carbon atoms, more preferably 5 to 10 carbon atoms.
The group in which the alkyl group and the alicyclic hydrocarbon group are combined preferably has a total carbon number of 18 or less in combination with these alkyl groups and the alicyclic hydrocarbon group.
^Ra04 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.
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.

The structural unit (a1-0), for example, the formula (a1-0-1) ~ expression methyl group hydrogen atoms corresponding to the structural units and ^{R a01} represented by any one of (a1-0-12) Examples of the structural unit have been replaced, and the structural unit represented by any of the formulas (a1-0-1) to (a1-0-10) is 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.

The structural unit (a1-2) includes a structural unit represented by any of the formulas (a1-2-1) to (a1-2-6) and a methyl group corresponding to ^{R a01} , R ^a4 and R ^a5. A structural unit in which is replaced with a hydrogen atom can be mentioned, and a structural unit represented by the formula (a1-2-2) or the formula (a1-2-5) is preferable.

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%, more preferably 20 to 85 mol%, based on the total unit.

［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＊−（ＣＨ₂）_h3−ＣＯ−Ｌ⁵⁴−を表し、ｈ３は１〜４のいずれかの整数を表し、＊は、Ｌ⁵¹との結合手を表す。
Ｌ⁵¹、Ｌ⁵²、Ｌ⁵³及びＬ⁵⁴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。 Examples of the structural unit having an acid unstable group include a structural unit represented by the formula (a1-5) (hereinafter, may be referred to as “structural unit (a1-5)”).

[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 −, h3 represents an integer of 1 to 4, and * represents a bond with ^{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. Group is mentioned.
In the formula (a1-5), R ^a8 represents a hydrogen atom, a methyl group or a trifluoromethyl group.
L ⁵¹ is preferably an oxygen atom.
It is preferable that one of L ⁵² and L ⁵³ is -O- and the other is -S-.
As s1, 1 is preferable.
As s1', any integer of 0 to 2 is preferable.
As Z ^a1 , a single bond or * -CH _2- CO-O- is preferable.

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

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, as the structural unit (a1), the structural unit (a1-3) shown below can also be mentioned.

［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.
The aromatic hydrocarbon group includes 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 monomer-derived structural unit 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（ａ１−３）又は構造単位（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 a structural unit (a1-3) or a structural unit (a1-4), the content thereof is preferably 10 to 95 mol% with respect to all the structural units of the resin (A), and 15 ~ 90 mol% is more preferable, and 20 to 85 mol% is even more preferable.

The structural unit (a1) having an acid unstable group in the resin (A) is a kind selected from the group consisting of a structural unit (a1-0), a structural unit (a1-1) and a structural unit (a1-2). The above is preferable, two or more kinds are more preferable, a combination of structural units (a1-1) and structural units (a1-2), a combination of structural units (a1-1) and structural units (a1-0), structural units ( The combination of a1-2) and the structural unit (a1-0), and the combination of the structural unit (a1-0), the structural unit (a1-1), and the structural unit (a1-2) are more preferable, and the structural unit (a1-) is more preferable. The combination of 1) and the structural unit (a1-2) is even more preferable.

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

<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 contain a structural unit (a2) having a phenolic hydroxy group. When an ArF excimer laser (193 nm) or the like is used, it is preferable that the structural unit (a2) includes 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%, preferably 10 to 80 mol%, based on the total structural units of the resin (A). % Is more preferred, and 15-80 mol% is even more preferred.

［式（ａ２−１）中、
Ｌ^a3は、−Ｏ−又は＊−Ｏ−（ＣＨ₂）_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。］ 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)”).

[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 to 4) , More preferably -O-.
R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of 0 to 3, and more preferably 0 or 1.

アルコール性ヒドロキシ基を有する構造単位（ａ２）を誘導するモノマーとしては、例えば、特開２０１０−２０４６４６号公報に記載されたモノマーが挙げられる。 Examples of the monomer for inducing the structural unit (a2-1) include the monomers described in JP-A-2010-204646. Monomers represented by any of the formulas (a2-1-1) to (a2-1-6) are preferable, and the monomers are represented by any of the formulas (a2-1-1) to (a2-1-4). The structural unit to be formed is more preferable, and the structural unit represented by the formula (a2-1-1) or the formula (a2-1-3) is further preferable.

Examples of the monomer for inducing the structural unit (a2) having an alcoholic hydroxy group include the monomers described in JP-A-2010-204646.

When the resin (A) contains a structural unit (a2) having an alcoholic hydroxy group, the content thereof is usually 1 to 45 mol%, preferably 1 to 45 mol%, based on the total structural units of the resin (A). It is 40 mol%, more preferably 1 to 35 mol%, still more preferably 2 to 20 mol%.

<Structural unit (a3)>
The lactone ring of the structural unit (a3) may be a monocyclic ring such as a β-propiolactone ring, a γ-butyrolactone ring, or a δ-valerolactone ring, or a fused ring of a monocyclic lactone ring and another ring. However, the lactone ring preferably includes a γ-butyrolactone ring, an adamantan lactone ring, or a bridged ring containing a γ-butyrolactone ring structure.

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

[In the formula (a3-1), the formula (a3-2), the formula (a3-3) and the formula (a3-4),
L ^a4 , ^{La 5} and ^{La 6} represent a group represented by -O- or ^* -O- (CH ₂ ) _k3- CO-O- (k3 represents an integer of 1 to 7). ..
L ^a7 is -O-, ^* -O-L ^a8- O-, ^* -O-L ^a8- CO-O-, ^* -O-L ^a8- CO-O-L ^a9- CO-O- or ^* -O-L ^a8- O-CO-L ^a9- O-represented.
^{La 8} and ^{La 9} each independently represent an alkanediyl group having 1 to 6 carbon atoms.
* Represents a bond with a carbonyl group.
R ^a18 , R ^a19 and R ^a20 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 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 / or w1 is 2 or more, a plurality of R ^a21 , R ^a22 , R ^a23 and / or R ^a25 may be the same or different from each other. ]

As ^{the aliphatic hydrocarbon group of R a21} , R ^a22 and R ^a23 , an alkyl group such as a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group and a tert-butyl group can be used. 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.

（式中、Ｒ^ａ２４、Ｌ^ａ７は、上記と同じ意味を表す。） In the formula (a3-1) ~ formula ^(a3-4), L a4 ^{~L a6} are each independently preferably -O- or, k3 is a integer of 1 to 4 * -O- ( CH ₂ ) _{A group represented by k3-} CO-O-, more preferably -O- and * -O-CH _2- CO-O-, and even more preferably an oxygen atom.
L ^a7 is preferably -O- or ^{* -O-L} a8 ^-CO-O-, more preferably an _{-O -, - O-CH 2} -CO-O- or _-O-C 2 _{H 4} - It is CO-O-.
R ^{a18 to} R ^a21 are preferably methyl groups.
^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.
The formula (a3-4) is particularly preferably the formula (a3-4)'.

(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 the formula (a3-1-1), the formula (a3-2-1), the formula (a3-2-2) and the formula (a3-2-2) are preferable. The structural unit represented by any of a3-4-1) to the formula (a3-4-6) is more preferable, and the formula (a3-1-1), the formula (a3-2-3) or the formula (a3-) The structural unit represented by 4-2) is 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られる。

In the above structural ^units, compounds methyl group corresponding to ^{R a18,} R ^a19, R ^a20 and ^{R a24} are replaced by a hydrogen atom, be mentioned as specific examples of the structural unit (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 all the structural units of the resin (A). , More preferably 10 to 60 mol%.
The content of each of the structural units represented by the formula (a3-1), the formula (a3-2), the formula (a3-3) and the formula (a3-4) is based on the total structural unit of the resin (A). , Usually 5-60 mol%, preferably 5-50 mol%, more preferably 10-50 mol%.

［式（ａ４−０）中、
Ｒ^５５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５〜１２のペルフルオロシクロアルカンジイル基を表す。
Ｒ^６６は、水素原子又はフッ素原子を表す。］ <Other structural units (t)>
The structural unit (t) that may be contained in the resin (A) of the present invention includes a structural unit (a2) and a structural unit (a3) that may have a halogen atom in addition to the structural unit (a2) and the structural unit (a3). (It is referred to as a “structural unit (a4)”) and a structural unit having a non-desorbed hydrocarbon group (hereinafter, may be referred to as a “structural unit (a5)”) and the like.
Examples of the structural unit (a4) include a structural unit represented by the formula (a4-0).

[In equation (a4-0),
R ⁵⁵ 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 5 to 12 carbon atoms.
R ⁶⁶ 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 Such as linear alkanediyl group, ethane-1,1-diyl group, propane-1,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1,3-diyl group and 2-. Examples thereof include a branched alkanediyl group such as a 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.
The perfluorocycloalkanes diyl group L ^3, perfluoro-cyclohexane diyl group, perfluoro cyclopentanediyl group, perfluoro cycloheptane-diyl group, a perfluoroalkyl adamantane-diyl 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.

上記の構造単位において、Ｒ⁵⁵に相当するメチル基が水素原子に置き換わった構造単位も、構造単位（ａ４−０）の具体例として挙げることができる。

In the above structural unit, a structural unit in ^{which the methyl group corresponding to R 55} is replaced with a hydrogen atom can also be mentioned as a specific example of the structural unit (a4-0).

［式（ａ４−１）中、
Ｒ^ａ４１は、水素原子又はメチル基を表す。
Ｒ^ａ４２は、置換基を有していてもよい炭素数１〜２０の炭化水素基を表し、該炭化水素基に含まれる−ＣＨ₂−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。

〔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、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又は単結合を表す。
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６以下である。〕
ただし、Ａ^a41及びＲ^a42のうち少なくとも一方は、置換基としてハロゲン原子を有する基である。
＊、＊＊は結合手であり、＊が−Ｏ−ＣＯ−Ｒ^ａ４２との結合手である。］
ｓは０が好ましい。 Examples of the structural unit (a4) include a structural unit represented by the formula (a4-1).

[In equation (a4-1),
R ^a41 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.
A ^a41 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 A a41} and R ^a42 has a halogen atom (preferably a fluorine atom) as a substituent.

[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 or a single bond having 1 to 5 carbon atoms which may have 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 6 or less.} ]
However, ^{at least one of A a41} and R ^a42 is a group having a halogen atom as a substituent.
* And ** are bonds, and * is a bond with -O-CO-R ^a42 . ]
s is preferably 0.

^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、例えば、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等が挙げられる。 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. The cyclic aliphatic hydrocarbon group includes a cycloalkyl group such as a cyclopentyl group, a cyclohexyl group, a cycloheptyl group and a cyclooctyl group; a decahydronaphthyl group, an adamantyl group, a 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。
＊はカルボニル基との結合手を表す。］ ^Examples of the substituent of R a42 include a halogen atom and 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 with a carbonyl group. ]

Examples of the aliphatic hydrocarbon group of A ^{a45 include} the same groups as those exemplified in ^{R a42.}
R ^a42 is preferably an aliphatic hydrocarbon group which may have a halogen atom, and more preferably an alkyl group having a halogen atom and / or an aliphatic hydrocarbon group having a group represented by the formula (ag3). ..

When R ^a42 is an aliphatic hydrocarbon group having a halogen atom, it is preferably an aliphatic hydrocarbon group having a fluorine atom, more preferably a perfluoroalkyl group or a perfluorocycloalkyl group, and further preferably having a carbon number of carbons. It is a perfluoroalkyl group of 1 to 6, 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.

［式（ａ−ｇ２）中、
Ａ^a46は、ハロゲン原子を有していてもよい炭素数１〜１７の脂肪族炭化水素基を表す。
Ｘ^a44は、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ^a47は、ハロゲン原子を有していてもよい炭素数１〜１７の脂肪族炭化水素基を表す。
ただし、Ａ^a46、Ａ^a47及びＸ^a44の炭素数の合計は１８以下であり、Ａ^a46及びＡ^a47のうち、少なくとも一方は、少なくとも１つのハロゲン原子を有する。
＊はカルボニル基との結合手を表す。］ The aliphatic hydrocarbon having a group represented by the formula (ag3) is more preferably a group represented by the formula (ag2).

[In the formula (ag2),
A ^a46 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
X ^a44 represents a carbonyloxy group or an oxycarbonyl group.
A ^a47 represents an aliphatic hydrocarbon group having 1 to 17 carbon atoms which may have a halogen atom.
However, the total number of carbon atoms of ^{A a46} , A ^a47 and X ^{a44 is 18 or less, and at least one of A a46} and A ^a47 has at least one halogen atom.
* Represents a bond with a carbonyl group. ]

The aliphatic hydrocarbon group of A ^a46 preferably has 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms.
The aliphatic hydrocarbon group of A ^a47 preferably has 4 to 15 carbon atoms, more preferably 5 to 12 carbon atoms, and even more preferably a cyclohexyl group or an adamantyl group.

Examples of the group represented by the formula (ag2) include the following groups.

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 A a41 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 of A a42} , A ^a43 and A ^{a44 in} the group represented by the formula (a-g1) (hereinafter, sometimes referred to as "group (ag1)") include a methylene group and an ethylene group. , Propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group Examples include a group, a 2-methylpropane-1,2-diyl group and the like. Examples of these substituents include a hydroxy group and an alkoxy group having 1 to 6 carbon atoms.

^{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 the bond, respectively, and ** is the bond with -O-CO-R ^a42 .

［式（ａ４−２）中、
Ｒ^ｆ1は、水素原子又はメチル基を表す。
Ａ^ｆ1は、炭素数１〜６のアルカンジイル基を表す。
Ｒ^ｆ2は、フッ素原子を有する炭素数１〜１０の炭化水素基を表す。］ As the structural unit represented by the formula (a4-1), the structural unit represented by the formula (a4-2) is preferable.

[In equation (a4-2),
R ^f1 represents a hydrogen atom or a methyl group.
A ^f1 represents an alkanediyl group having 1 to 6 carbon atoms.
R ^f2 represents a hydrocarbon group having 1 to 10 carbon atoms having a fluorine atom. ]

The ^{alkanediyl group of A f1} includes a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, and a pentane-1,5-diyl group. , Hexine-1,6-diyl group and other linear alkanediyl groups; 1-methylpropane-1,3-diyl group, 2-methylpropane-1,3-diyl group, 2-methylpropane-1,2 Examples thereof include branched alkanediyl groups such as −diyl group, 1-methylbutane-1,4-diyl group and 2-methylbutane-1,4-diyl group.

Examples of the hydrocarbon group of R ^f2 include a chain type and a ring type aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a group formed by combining these groups. As the aliphatic hydrocarbon group, an alkyl group (straight or branched) and an alicyclic hydrocarbon group are preferable.
Alkyl groups include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, n-pentyl group, n-hexyl group, n-octyl group and 2 -Ethylhexyl group is mentioned.
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, cycloheptyl group and cyclodecyl group. 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 hydrocarbon group having a fluorine atom of R ^f2 include an alkyl group having a fluorine atom and an alicyclic hydrocarbon group having a fluorine atom.
Specifically, examples of the alkyl group having a fluorine atom include a difluoromethyl group, a trifluoromethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, and a 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, Perfluoropropyl group, 1,1,2,2-Tetrafluorobutyl group, 1,1,2,2,3,3-Hexafluorobutyl 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, 1,1,2,2,3,3,4,5-octafluoropentyl group, perfluoropentyl group, 1,1,2,2,3,3,4,5,5-decafluoropentyl group, 1,1-bis (trifluoromethyl) -2,2,3,3,3-pentafluoropropyl group, perfluoropentyl group, 2- (perfluorobutyl) ethyl group, 1,1,2,2,3,3 , 4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,5,5,6,6-dodecafluorohexyl group, perfluoropentylmethyl group and perfluorohexyl Fluoroalkyl groups such as groups can be mentioned.
Examples of the alicyclic hydrocarbon group having a fluorine atom include a fluorocycloalkyl group such as a perfluorocyclohexyl group and a perfluoroadamantyl group.

In the formula (a4-2), A ^f1 is preferably an alkanediyl group having 2 to 4 carbon atoms, and more preferably an ethylene group.
As R ^f2 , an alkyl fluoride group having 1 to 6 carbon atoms is preferable.
As the structural unit represented by the formula (a4-2), the structural unit represented by the formulas (a4-1-1) to (a4-1-11) and the methyl group corresponding to ^{R f1 are hydrogen atoms.} Examples include replaced structural units.

Examples of the structural unit (a4) include the following structural unit and a structural unit in which a methyl group corresponding to ^{R f11 is replaced with a hydrogen atom.}

Examples of the structural unit (a4) include the following structural unit and a structural unit in which a methyl group corresponding to ^{R f21 is replaced with a hydrogen atom.}

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

Examples of the non-eliminating hydrocarbon group contained in the structural unit (a5) include the following structural unit and a structural unit in which a methyl group corresponding to ^{R 51 is replaced with a hydrogen atom.}

When the resin (A) has a structural unit (a5), the content thereof is preferably 1 to 30 mol%, more preferably 2 to 20 mol%, and 3) with respect to all the structural units of the resin (A). ~ 15 mol% is more preferred.

The resin (A) is preferably a resin composed of a structural unit (a1) and a structural unit (s), that is, a copolymer of a monomer (a1) and a monomer (s).
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 at least one selected from the structural unit represented by the formula (a3-14) and the structural unit represented by the formula (a3-4).

Each structural unit constituting the resin (A) may be used alone or in combination of two or more, and is produced by a known polymerization method (for example, a radical polymerization method) using a monomer for inducing these structural units. can do. 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)>
Examples of the resin other than the resin (A) include a resin containing a structural unit (t), for example, a resin (X) and the like. The resin (X) is preferably a resin containing the structural unit (a4) (however, the resin (X) does not include the structural unit (a1)).
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 the total 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.

<Acid generator>
The acid generator in the resist composition of the present invention includes the above-mentioned acid generator containing only the salt (I), the acid generator containing only the acid generator (B), the salt (I) and the acid generator (B). Any of the acid generators contained therein may be used, and an acid generator containing a salt (I) and an acid generator (B) is preferable.
The content of the acid generator in the resist composition is preferably 1.5 to 40 parts by weight, more preferably 3 to 35 parts by weight, based on 100 parts by weight of the resin (A).

<Solvent (E)>
The content of the solvent (E) in the resist composition 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. It is preferably 99% by mass or less. 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)>
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 generated from an acid generator.
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.

Examples of amines include 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, tri Heptylamine, 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, tri Isopropanolamine, 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-di) Pyridyl) ethane, 1,2-di (2-pyridyl) ethene, 1,2-di (4-pyridyl) ethane, 1,3-di (4-pyridyl) propane, 1,2-di (4-pyridyloxy) ) Ethan, di (2-pyridyl) ketone, 4,4'-dipyridyl sulfide, 4,4'-dipyridyl disulfide, 2,2'-dipyridylamine, 2,2'-dipicorylamine, bipyridine and the like. Diisopropylaniline is preferable, and 2,6-diisopropylaniline is more preferable.

Examples of the ammonium salt include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, and 3- (trifluoromethyl) phenyltrimethyl. Examples thereof include ammonium hydroxide, tetra-n-butylammonium salicylate and choline.

The acidity of a salt that produces an acid that is weaker than the acid generated from the salt (I) and the acid generator (B) is indicated by the acid dissociation constant (pKa). A salt that generates an acid having a weaker acidity than the acid generated from the salt (I) and the acid generator (B) usually has an acid dissociation constant of -3 <pKa. A salt of -1 <pKa <7 is preferable, and a salt of 0 <pKa <5 is more preferable.
Examples of the salt that generates an acid having a weaker acidity than the acid generated from the salt (I) and the acid generator (B) include a salt represented by the following formula, which is the formula (D) described in JP-A-2015-147926. (Hereinafter, it may be referred to as a weak acid intramolecular salt (D)) and JP-A-2012-229206, JP-A-2012-6908, JP-A-2012-72109, JP-A-2011- Examples thereof include salts described in JP-A-39502 and JP-A-2011-191745. It is preferably a salt having a weak acid content represented by the formula (D).

The content of the quencher (C) is preferably 0.01 to 5% by mass, more preferably 0.01 to 3% by mass, based on the solid content of the resist composition.

<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 a resin (A), a salt (I) of the present invention, a resin other than the resin (A) used as needed, an acid generator (B), a solvent (E), and a citric acid. It can be prepared by mixing the char (C) and the other component (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. Exposure light sources include those that emit ultraviolet laser light such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), and F ₂ excimer laser (wavelength 157 nm), and solid-state laser light sources (YAG or semiconductor laser). Etc.), wavelength-converted laser light from far-ultraviolet region or vacuum ultraviolet region to emit harmonic laser light, electron beam, super-ultraviolet light (EUV) irradiation, etc. Can be done. In addition, in this specification, irradiation of 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 unstable 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, for example, 5 to 60 ° C., and the developing time is preferably, for example, 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 the 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 thereof 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 rinsing solution. The rinsing solution 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.

<Use>
The resist composition of the present invention is suitable as 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. Yes, it is more suitable as a resist composition for ArF excimer laser 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 determined by gel permeation chromatography. The analysis conditions for gel permeation chromatography are as follows.
Column: TSKgel Multipore HXL-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 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−１−ａ）で表される化合物５部及びアセトニトリル２５部を混合し、２３℃で３０分間攪拌した。その後、式（Ｉ−１−ｃ）で表される化合物４．７部及び式（Ｉ−１−ｂ）で表される化合物５．５部を添加し、２３℃で３６時間攪拌した。得られた反応溶液をろ過した。回収されたろ液を濃縮することにより、式（Ｉ−１−ｄ）で表される塩７．１１部を得た。 Example 1: Synthesis of salt represented by formula (I-1)

5 parts of the compound represented by the formula (I-1-a) and 25 parts of acetonitrile were mixed and stirred at 23 ° C. for 30 minutes. Then, 4.7 parts of the compound represented by the formula (I-1-c) and 5.5 parts of the compound represented by the formula (I-1-b) were added, and the mixture was stirred at 23 ° C. for 36 hours. The resulting reaction solution was filtered. By concentrating the recovered filtrate, 7.11 parts of a salt represented by the formula (I-1-d) was obtained.

式（Ｉ−１−ｄ）で表される塩４．１部、式（Ｉ−１−ｅ）で表される塩４部、クロロホルム４０部及びイオン交換水１３．３部を混合し、２３℃で５時間攪拌した。得られた反応液を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１５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３回繰り返した。得られた有機層を濃縮し、得られた残渣に、ｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌し、上澄み液を除去した。得られた残渣を濃縮することにより、式（Ｉ−１）で表される塩４．８９部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２２９．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ２７９．９

4.1 parts of the salt represented by the formula (I-1-d), 4 parts of the salt represented by the formula (I-1-e), 40 parts of chloroform and 13.3 parts of ion-exchanged water are mixed and 23. The mixture was stirred at ° C. for 5 hours. The obtained reaction solution was separated and the organic layer was taken out. 15 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, separated and the organic layer was taken out. This washing operation was repeated 3 times. The obtained organic layer was concentrated, 30 parts of tert-butyl methyl ether was added to the obtained residue, and the mixture was stirred to remove the supernatant. By concentrating the obtained residue, 4.89 parts of a salt represented by the formula (I-1) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 229.1
MASS (ESI (-) Spectrum): M ^- 279.9

式（Ｉ−１−ｄ）で表される塩４．１部、式（Ｉ−２−ｅ）で表される塩５部、クロロホルム４０部及びイオン交換水１３．３部を混合し、２３℃で５時間攪拌した。得られた反応液を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１５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３回繰り返した。得られた残渣を濃縮した後、得られた残渣に、ｎ−ヘプタン１００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４．８２部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２２９．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ３７９．９ Example 2: Synthesis of salt represented by formula (I-2)

4.1 parts of the salt represented by the formula (I-1-d), 5 parts of the salt represented by the formula (I-2-e), 40 parts of chloroform and 13.3 parts of ion-exchanged water are mixed and 23. The mixture was stirred at ° C. for 5 hours. The obtained reaction solution was separated and the organic layer was taken out. 15 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, separated and the organic layer was taken out. This washing operation was repeated 3 times. After concentrating the obtained residue, 100 parts of n-heptane was added to the obtained residue, stirred, and filtered to obtain 4.82 parts of a salt represented by the formula (I-2).
MASS (ESI (+) Spectrum): M ⁺ 229.1
MASS (ESI (-) Spectrum): M ^- 379.9

式（Ｉ−１−ｄ）で表される塩４．１部、式（Ｉ−４−ｅ）で表される塩３．９部、クロロホルム４０部及びイオン交換水１３．３部を仕込んだ後、２３℃で５時間攪拌した。得られた反応液を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１５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３回繰り返した。得られた残渣を濃縮し、得られた残渣に、ｎ−ヘプタン１００部を加えて攪拌した。その後、ろ過することにより、式（Ｉ−４）で表される塩５．５２部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２２９．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ２９１．９ Example 3: Synthesis of salt represented by formula (I-4)

4.1 parts of the salt represented by the formula (I-1-d), 3.9 parts of the salt represented by the formula (I-4-e), 40 parts of chloroform and 13.3 parts of ion-exchanged water were charged. Then, the mixture was stirred at 23 ° C. for 5 hours. The obtained reaction solution was separated and the organic layer was taken out. 15 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, separated and the organic layer was taken out. This washing operation was repeated 3 times. The obtained residue was concentrated, and 100 parts of n-heptane was added to the obtained residue and stirred. Then, by filtration, 5.52 parts of a salt represented by the formula (I-4) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 229.1
MASS (ESI (-) Spectrum): M ^- 291.9

式（Ｉ−５−ａ）で表される化合物５部、メタノール１５部及びアセトン２５部を混合し、２３℃で３０分間攪拌した。得られた混合溶液に、３１％過酸化水素水１０．５部を添加し、さらに、２３℃で２４時間攪拌した。得られた混合物を濃縮した。濃縮残に、クロロホルム４０部及びイオン交換水２０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２０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。この操作を３回繰り返した。得られた有機層を濃縮することにより、式（Ｉ−５−ｂ）で表される化合物５．３７部を得た。 Example 4: Synthesis of salt represented by formula (I-5)

5 parts of the compound represented by the formula (I-5a), 15 parts of methanol and 25 parts of acetone were mixed and stirred at 23 ° C. for 30 minutes. To the obtained mixed solution, 10.5 parts of 31% hydrogen peroxide solution was added, and the mixture was further stirred at 23 ° C. for 24 hours. The resulting mixture was concentrated. 40 parts of chloroform and 20 parts of ion-exchanged water were added to the concentrated residue, and the mixture was stirred at 23 ° C. for 30 minutes and separated to remove the organic layer. To the recovered organic layer, 20 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 operation was repeated 3 times. By concentrating the obtained organic layer, 5.37 parts of the compound represented by the formula (I-5-b) was obtained.

式（Ｉ−５−ｂ）で表される化合物５．４部及びテトラヒドロフラン３０部を混合し、２３℃で３０分間攪拌した。得られた混合溶液に、式（Ｉ−５−ｄ）で表される化合物５．１部を添加した後、次いで、式（Ｉ−５−ｃ）で表される化合物５．１部を添加し、２３℃で２時間攪拌した。得られた混合物に、１Ｎ塩酸１４．４５部を加えて２３℃で３０分間攪拌し、分液して水層を取り出した。回収された水層に、ｔ−ブチルメチルエーテル３０部を加えて２３℃で３０分間攪拌し、分液して水層を取り出した。回収された水層に、クロロホルム３０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。得られた有機層を濃縮することにより、式（Ｉ−５―ｅ）で表される塩４．１５部を得た。

5.4 parts of the compound represented by the formula (I-5-b) and 30 parts of tetrahydrofuran were mixed and stirred at 23 ° C. for 30 minutes. To the obtained mixed solution, 5.1 part of the compound represented by the formula (I-5d) was added, and then 5.1 part of the compound represented by the formula (I-5-c) was added. Then, the mixture was stirred at 23 ° C. for 2 hours. 14.45 parts of 1N hydrochloric acid was added to the obtained mixture, and the mixture was stirred at 23 ° C. for 30 minutes, separated and the aqueous layer was taken out. To the recovered aqueous layer, 30 parts of t-butyl methyl ether was added, and the mixture was stirred at 23 ° C. for 30 minutes, separated and the aqueous layer was taken out. To the recovered aqueous layer, 30 parts of chloroform was added, and the mixture was stirred at 23 ° C. for 30 minutes, separated into liquids, and the organic layer was taken out. By concentrating the obtained organic layer, 4.15 parts of a salt represented by the formula (I-5-e) was obtained.

式（Ｉ−５−ｅ）で表される塩４．１部、式（Ｉ−１−ｅ）で表される化合物４部、クロロホルム４０部及びイオン交換水１３．３部を仕込み、２３℃で５時間攪拌した。得られた反応液を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１５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３回繰り返した。得られた残渣を濃縮した。得られた残渣に、ｎ−ヘプタン１００部を加えて攪拌した後、ろ過することにより、式（Ｉ−５）で表される塩４．１２部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２９１．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ２７９．９

4.1 parts of the salt represented by the formula (I-5e), 4 parts of the compound represented by the formula (I-1-e), 40 parts of chloroform and 13.3 parts of ion-exchanged water were charged at 23 ° C. Was stirred for 5 hours. The obtained reaction solution was separated and the organic layer was taken out. 15 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, separated and the organic layer was taken out. This washing operation was repeated 3 times. The obtained residue was concentrated. To the obtained residue, 100 parts of n-heptane was added, stirred, and then filtered to obtain 4.12 parts of a salt represented by the formula (I-5).
MASS (ESI (+) Spectrum): M ⁺ 291.1
MASS (ESI (-) Spectrum): M ^- 279.9

式（Ｉ−５−ｅ）で表される塩４．１部、式（Ｉ−２−ｅ）で表される塩５部、クロロホルム４０部及びイオン交換水１３．３部を混合し、２３℃で５時間攪拌した。得られた反応液を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１５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３回繰り返した。得られた残渣を濃縮した後、得られた残渣に、ｎ−ヘプタン１００部を加えて攪拌し、ろ過することにより、式（Ｉ−６）で表される塩４．２５部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２９１．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ３７９．９ Example 5: Synthesis of salt represented by formula (I-6)

4.1 parts of the salt represented by the formula (I-5e), 5 parts of the salt represented by the formula (I-2-e), 40 parts of chloroform and 13.3 parts of ion-exchanged water are mixed and 23. The mixture was stirred at ° C. for 5 hours. The obtained reaction solution was separated and the organic layer was taken out. 15 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, separated and the organic layer was taken out. This washing operation was repeated 3 times. After concentrating the obtained residue, 100 parts of n-heptane was added to the obtained residue, stirred, and filtered to obtain 4.25 parts of a salt represented by the formula (I-6).
MASS (ESI (+) Spectrum): M ⁺ 291.1
MASS (ESI (-) Spectrum): M ^- 379.9

式（Ｉ−５−ｅ）で表される塩４．１部、式（Ｉ−４−ｅ）で表される塩３．９部、クロロホルム４０部及びイオン交換水１３．３部を仕込んだ後、２３℃で５時間攪拌した。得られた反応液を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１５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３回繰り返した。得られた残渣を濃縮し、得られた残渣に、ｎ−ヘプタン１００部を加えて攪拌した。その後、ろ過することにより、式（Ｉ−８）で表される塩４．１２部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ２９１．１
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ２９１．９ Example 6: Synthesis of salt represented by formula (I-8)

4.1 parts of the salt represented by the formula (I-5e), 3.9 parts of the salt represented by the formula (I-4-e), 40 parts of chloroform and 13.3 parts of ion-exchanged water were charged. Then, the mixture was stirred at 23 ° C. for 5 hours. The obtained reaction solution was separated and the organic layer was taken out. 15 parts of ion-exchanged water was added to the recovered organic layer, and the mixture was stirred at 23 ° C. for 30 minutes, separated and the organic layer was taken out. This washing operation was repeated 3 times. The obtained residue was concentrated, and 100 parts of n-heptane was added to the obtained residue and stirred. Then, by filtration, 4.12 parts of a salt represented by the formula (I-8) was obtained.
MASS (ESI (+) Spectrum): M ⁺ 291.1
MASS (ESI (-) Spectrum): M ^- 291.9

Synthesis of Resin (A) The compounds (monomers) used for the synthesis of resin (A) are shown below. Hereinafter, these compounds will be referred to as "monomer (a1-1-2)" or the like according to the formula number.

Synthesis Example 1 [Synthesis of resin A1]
The molar ratio of the monomer (a1-1-2), the monomer (a1-2-5), the monomer (a2-1-1) and the monomer (a3-1-1) [monomer (a1-1-2): Monomer (a1-2-5): Monomer (a2-1-1): Monomer (a3-1-1)] is mixed so as to be 5:42:32:21, which is 2% by mass of the total amount of monomer. Propropylene glycol monomethyl ether acetate 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. did. 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. the resin A1 having a molecular weight of 9.1 × 10 ³ was obtained in 97% yield. This resin A1 has the following structural units.

Synthesis Example 2 [Synthesis of resin X1]
A monomer (a4-1-4) was used as a monomer, and methyl isobutyl ketone, which was 1.2% by mass of the total amount of the monomer, was added to prepare a solution. Azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to this solution in an amount of 0.7 mol% and 2.1 mol%, respectively, based on the total amount of monomers, and these were added at 75 ° C. It was heated for about 5 hours. 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 repulped with methanol / water mixed solvent, by filtration, to obtain a resin X1 of weight average molecular weight 1.7 × 10 ⁴ in 76% yield. 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 1, dissolved in a solvent, and filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

Ｂ−Ｘ１：特開２００２−２６８２２３号公報の実施例に従って合成

＜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 １００部
プロピレングリコールモノメチルエーテル ２０部 <Resin (A)>
A1, X1: Resin A1, Resin X1
<Acid generator>
I-1: Salt represented by the formula (I-1) I-2: Salt represented by the formula (I-2) I-4: Salt represented by the formula (I-4) I-5: Formula represented by the formula (I-4) Salt represented by (I-5) I-6: Salt represented by formula (I-6) I-8: Salt represented by formula (I-8) B1-21: Salt represented by formula (B1-21) Salt represented by (Synthesized according to an example of JP2012-224611A)
B1-22: Salt represented by the formula (B1-22) (synthesized according to an example of JP2012-224611)

B-X1: Synthesized according to the examples of JP-A-2002-268223

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

<Solvent>
Propylene Glycol Monomethyl Ether Acetate 100 Parts Propylene Glycol Monomethyl Ether 20 Parts

<Manufacturing of resist pattern>
_{A 12-inch silicon wafer having two} layers of SiO having a film thickness of 100 nm formed on its surface is treated with hexamethyldisilazane at 120 ° C. for 60 seconds, and then the resist composition has a film thickness of 240 nm after prebaking. Spin-coated like this.
The silicon wafer coated with the resist composition was prebaked on a direct hot plate at the temperature listed in the “PB” column of Table 1 for 60 seconds to form a composition layer. ArF excimer laser stepper for immersion exposure [XT: 1900Gi; manufactured by ASML, NA = 0.90, Annular, σout / σin = 0.75 / 0. 40, XY polarized light], the line and space pattern was immersed and exposed by subjecting the exposure amount in a stepwise manner using a mask for forming a line and space pattern (pitch 300 nm / space 114 nm). Ultrapure water was used as the immersion medium.
After exposure, post-exposure baking is performed on a hot plate at the temperature listed in the “PEB” column of Table 1 for 60 seconds, and further paddle development is performed for 60 seconds with a 2.38 mass% tetramethylammonium hydroxide aqueous solution. This was performed to obtain a resist pattern.

In the obtained resist pattern, the exposure amount at which the space width of the pattern was 130 nm was defined as the effective sensitivity.

<Line edge roughness evaluation (LER)>
With respect to the obtained resist pattern, the swing width of the unevenness of the wall surface was observed and measured with a scanning electron microscope. This swing width is shown in Table 2 as LER (nm).

From the above results, it can be seen that the resist composition containing the salt of the present invention and the acid generator containing the same can produce a resist pattern with excellent line edge roughness.

According to the resist composition containing the salt of the present invention and an acid generator containing the same, a resist pattern having excellent line edge roughness can be produced, which is suitable for microfabrication of semiconductors and is industrially useful. be.

Claims (7)

A resist composition containing a salt represented by the formula (I) and a resin containing a structural unit having an acid unstable group .

[In formula (I),
Ar ¹ and Ar ² are independently aromatic hydrocarbon groups having 6 to 36 carbon atoms which may have substituents or heteroaromatics having 4 to 36 carbon atoms which may have substituents. Represents a hydrocarbon group.
X ¹ and X ² each independently represent an alkanediyl group having 1 to 6 carbon atoms.
R ¹ represents a hydrocarbon group having 1 to 18 carbon atoms which may have a substituent.
R ⁵ and R ⁶ each independently represent an alkyl group having 1 to 4 carbon atoms having a fluorine atom, or bond with each other to form a divalent heterocycle having 2 to 8 carbon atoms having a fluorine atom. ] The resist composition according to claim 1, wherein both Ar ¹ and Ar ² are phenyl groups which may have a substituent. The resist composition according to claim 1 or 2, wherein both X ¹ and X ² are methylene groups. The resist composition according to any one of claims 1 to 3, wherein the resin containing a structural unit having an acid unstable group further contains a structural unit having a lactone ring. The resist composition according to any one of claims 1 to 4, further containing a salt that generates an acid having a weaker acidity than the acid generated from the salt represented by the formula (I). The resist composition according to any one of claims 1 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 1 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.