JP2013047209A - Salt and resist composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a salt useful as an acid generator for a resist composition, and to provide an excellent resist composition containing the salt, or the like.SOLUTION: This salt is expressed by formula (1), where in formula (1), Rrepresents an aromatic hydrocarbon group; Rrepresents an acidolyzing group; Rrepresents H or a hydroxy group; Xand Xeach independently represent a group represented by formula (a-g1) (wherein, s denotes an integer of 0-2; Aand Aeach independently represent an aliphatic hydrocarbon group; Xrepresents O, a carbonyl group, carbonyloxy group or oxycarbonyl group), m1 denotes 1 or 2 and m2 denotes 0 or 1, provided that a relation m1+m2=2 is satisfied; Arepresents an organic anion selected from the group consisting of a sulfonic anion, sulfonylimide anion, sulfonylmethide anion and carboxylic anion.

Description

  The present invention relates to a novel salt for an acid generator for a resist composition, a resist composition containing the salt, and the like.

  A chemically amplified resist composition used for microfabrication of a semiconductor by lithography technology contains an acid generator and a resin that is insoluble or hardly soluble in an aqueous alkali solution and can be dissolved in an aqueous alkali solution by the action of an acid. In recent years, the use of a salt having an acid-decomposable group in the molecule as the acid generator has been studied.

As such an acid generator for a resist composition, for example, Patent Document 1 describes a salt represented by the following formula (X1).

JP 2010-44347 A

  A resist pattern obtained using a resist composition containing the salt represented by the formula (X1) as an acid generator may not always have a sufficient focus margin (DOF).

［式（Ｉ）中、
Ｒ^１は、置換基を有してもよい炭素数６〜１８の芳香族炭化水素基を表す。
Ｒ^２は、酸分解性基を表す。
Ｒ^３は、水素原子又はヒドロキシ基を表す。
Ｘ^１及びＸ^２は、それぞれ独立に、式（ａ−ｇ１）

（式（ａ−ｇ１）中、
ｓは０〜２の整数を表す。
Ａ^１０及びＡ^１１は、それぞれ独立に、炭素数１〜５の脂肪族炭化水素基を表す。
ｓが２のとき、複数存在するＡ^１０は、互いに同一であっても異なっていてもよい。
Ｘ^１０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。
ｓが２のとき、複数存在するＸ^１０は、互いに同一であっても異なっていてもよい。）
で表される基を表す。
ｍ１は１又は２を表し、ｍ２は０又は１を表す。但し、ｍ１＋ｍ２＝２の関係を満たす。
ｍ１が２の時、複数存在するＸ^１は互いに同一であっても異なっていてもよく、複数存在するＲ^２は互いに同一であっても異なっていてもよい。
Ａ⁻は、スルホン酸アニオン、スルホニルイミドアニオン、スルホニルメチドアニオン及びカルボン酸アニオンからなる群から選ばれる有機アニオンを表す。］
〔２〕前記式（Ｉ）のＲ^２が、式（１）で表される酸分解性基である、前記〔１〕記載の塩。

［式（１）中、
Ｒ^a1、Ｒ^ａ２及びＲ^a3は、それぞれ独立に、炭素数１〜８のアルキル基又は炭素数３〜２０の脂環式炭化水素基を表すか、Ｒ^a1及びＲ^a2は互いに結合して炭素数２〜２０の２価の炭化水素基を形成する。＊は結合手を表す。］
〔３〕前記式（Ｉ）のＸ^１は、
ｓが１であり、Ａ^１０及びＡ^１１がそれぞれ独立に炭素数１〜５のアルカンジイル基であり、かつＸ^１０が酸素原子である前記式（ａ−ｇ１）で表される基であり、
Ｘ^２は炭素数１〜５のアルカンジイル基である、前記〔２〕記載の塩。
〔４〕前記式（Ｉ）のＲ^１が、置換基を有してもよいフェニル基である、前記〔１〕〜〔３〕のいずれか記載の塩。
〔５〕前記〔１〕〜〔４〕のいずれか記載の塩と、
アルカリ水溶液に不溶又は難溶であり、酸の作用によりアルカリ水溶液に溶解し得る樹脂とを含有するレジスト組成物。
〔６〕さらに、塩基性化合物を含有する、前記〔５〕記載のレジスト組成物。
〔７〕さらに溶剤を含有する、前記〔５〕又は〔６〕記載のレジスト組成物。
〔８〕（１）前記〔５〕〜〔７〕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 following formula (I).

[In the formula (I),
R ¹ represents an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent.
R ² represents an acid-decomposable group.
R ³ represents a hydrogen atom or a hydroxy group.
X ¹ and X ² each independently represent the formula (a-g1)

(In the formula (a-g1),
s represents the integer of 0-2.
A ¹⁰ and A ¹¹ each independently represent an aliphatic hydrocarbon group having 1 to 5 carbon atoms.
When s is 2, the plurality of A ¹⁰ may be the same as or different from each other.
X ¹⁰ represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
When s is 2, a plurality of X ¹⁰ may be the same as or different from each other. )
Represents a group represented by
m1 represents 1 or 2, and m2 represents 0 or 1. However, the relationship of m1 + m2 = 2 is satisfied.
When m1 is 2, a plurality of X ¹ may be the same or different, and a plurality of R ² may be the same or different.
A ⁻ represents an organic anion selected from the group consisting of a sulfonate anion, a sulfonylimide anion, a sulfonylmethide anion, and a carboxylate anion. ]
[2] The salt according to [1], wherein R ² in the formula (I) is an acid-decomposable group represented by the formula (1).

[In Formula (1),
R ^a1 , R ^a2 and R ^a3 each independently represent an alkyl group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R ^a1 and R ^a2 are bonded to each other to form carbon A divalent hydrocarbon group of 2 to 20 is formed. * Represents a bond. ]
[3] X ^{1 in the} formula (I) is
s is 1, A ¹⁰ and A ¹¹ are each independently an alkanediyl group having 1 to 5 carbon atoms, and X ¹⁰ is an oxygen atom, and is a group represented by the above formula (a-g1),
X < ² > is the salt of the said [2] description which is a C1-C5 alkanediyl group.
[4] The salt according to any one of [1] to [3], wherein R ^{1 in the} formula (I) is a phenyl group which may have a substituent.
[5] The salt according to any one of [1] to [4],
A resist composition containing a resin that is insoluble or hardly soluble in an alkaline aqueous solution and that can be dissolved in an alkaline aqueous solution by the action of an acid.
[6] The resist composition according to [5], further comprising a basic compound.
[7] The resist composition according to [5] or [6], further containing a solvent.
[8] (1) The process of apply | coating the resist composition in any one of said [5]-[7] on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a 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:

  If the salt of this invention is used as an acid generator, the resist composition which can manufacture a resist pattern with the outstanding focus margin (DOF) can be obtained.

As described above, the salt of the present invention is represented by the formula (I). Hereinafter, the salt represented by the formula (I) is sometimes referred to as “salt (I)”.
The present invention also provides the salt (I),
A resist composition (hereinafter, sometimes referred to as “resin (A)”) that is insoluble or hardly soluble in an alkaline aqueous solution and can be dissolved in an alkaline aqueous solution by the action of an acid. Resist composition ”).
The resist composition further contains a basic compound (hereinafter sometimes referred to as “basic compound (C)”) and a solvent (hereinafter sometimes referred to as “solvent (D)”). It is preferable.
First, the constituents of the resist composition will be described in the order of the salt (I), the resin (A), and if necessary, the basic compound (C) and the solvent (D) contained in the resist composition. The method for preparing the resist composition and the method for producing a resist pattern using the resist composition will be described.

Before describing the components of the resist composition, common substituents and the like in this specification will be described. In the present specification, unless otherwise specified, the following examples of substituents are applied to any chemical structural formula having the same substituents while appropriately selecting the number of carbon atoms. Among the aliphatic hydrocarbon groups, those that can be linear or branched, such as an alkyl group, include any of them. When stereoisomers exist, all stereoisomers are included. In the following examples of substituents, the numerical value attached to “C” indicates the number of carbon atoms of each group.
Further, in the present specification, "(meth) acrylic monomer", "CH ₂ = CH-CO-" or _{"CH 2 = C (CH 3)} -CO- " at least one monomer having the structure Means. 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 hydrocarbon group includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group.
The aliphatic hydrocarbon group includes both a chain type and a cyclic type, and includes a combination of a chain type and an alicyclic aliphatic hydrocarbon group unless otherwise defined. Further, these aliphatic hydrocarbon groups may contain a carbon-carbon double bond in a part thereof, but a saturated group (aliphatic saturated hydrocarbon group) is preferable.

Of the chain aliphatic hydrocarbon groups, the monovalent one typically includes an alkyl group. Specific examples of the alkyl group include a methyl group (C ₁ ), an ethyl group (C ₂ ), a propyl group (C ₃ ), a butyl group (C ₄ ), a pentyl group (C ₅ ), a hexyl group (C ₆ ), heptyl _(C 7), octyl _(C 8), decyl (C _10), dodecyl (C _12), hexadecyl (C _14), pentadecyl (C _15), hexyl decyl group (C _16), A heptadecyl group (C ₁₇ ) and an octadecyl group (C ₁₈ ).
Examples of the divalent group of chain aliphatic hydrocarbon groups include alkanediyl groups in which one hydrogen atom has been removed from an alkyl group. Specific examples of the alkanediyl group include methylene group, ethylene group, propane-1,3-diyl group, propane-1,2-diyl group, butane-1,4-diyl group, pentane-1,5-diyl group, Hexane-1,6-diyl group, heptane-1,7-diyl group, octane-1,8-diyl group, nonane-1,9-diyl group, decane-1,10-diyl group, undecane-1,11 -Diyl group, dodecane-1,12-diyl group, tridecane-1,13-diyl group, tetradecane-1,14-diyl group, pentadecane-1,15-diyl group, hexadecane-1,16-diyl group, heptadecane -1,17-diyl group, ethane-1,1-diyl group, propane-1,1-diyl group, propane-2,2-diyl group, butane-1,3-diyl group, 2-methylpropane-1 , 3- Yl group, 2-methylpropane-1,2-diyl, pentane-1,4-diyl group and 2-methylbutane-1,4-diyl group and the like.

  The cyclic aliphatic hydrocarbon group (hereinafter sometimes referred to as “alicyclic hydrocarbon group” in some cases) is typically a cycloalkyl group, and any of the monocyclic and polycyclic groups shown below can be used. Is also included.

As a monovalent alicyclic hydrocarbon group, a monocyclic aliphatic hydrocarbon group represents 1 hydrogen atom of a cycloalkane represented by the following formulas (KA-1) to (KA-7). It is a group that has been removed.

The polycyclic aliphatic hydrocarbon group is a group in which one hydrogen atom of a cycloalkane represented by the following formulas (KA-8) to (KA-22) is removed.

  Examples of the divalent alicyclic hydrocarbon group include groups in which two hydrogen atoms have been removed from the alicyclic hydrocarbon of formula (KA-1) to formula (KA-22).

  The aliphatic hydrocarbon group may have a substituent. Such a substituent is defined each time, and examples thereof include a halogen atom, a hydroxy group, an alkoxy group, an acyl group, an acyloxy group, an aryl group, an aralkyl group, and an aryloxy group.

Examples of alkoxy groups include methoxy group (C ₁ ), ethoxy group (C ₂ ), propoxy group (C ₃ ), butoxy group (C ₄ ), pentyloxy group (C ₅ ), hexyloxy group (C ₆ ), heptyl Examples thereof include an oxy group (C ₇ ), an octyloxy group (C ₈ ), a decyloxy group (C ₁₀ ), and a dodecyloxy group (C ₁₂ ).
Examples of the acyl group include acetyl group (C ₂ ), propionyl group (C ₃ ), butyryl group (C ₄ ), valeryl group (C ₅ ), hexanoyl group (C ₆ ), heptanoyl group (C ₇ ), octanoyl group ( C ₈ ), decanoyl group (C ₁₀ ) and dodecanoyl group (C ₁₂ ) and other alkyl groups and carbonyl groups bonded, and benzoyl group (C ₇ ) and other aryl groups and carbonyl groups bonded Can be mentioned.
Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, and an isobutyryloxy group.
Examples of the aralkyl group include benzyl group (C ₇ ), phenethyl group (C ₈ ), phenylpropyl group (C ₉ ), naphthylmethyl group (C ₁₁ ), and naphthylethyl group (C ₁₂ ).
Aryloxy groups include phenyloxy group (C ₆ ), naphthyloxy group (C ₁₀ ), anthryloxy group (C ₁₄ ), biphenyloxy group (C ₁₂ ), phenanthryloxy group (C ₁₄ ) and full A combination of an aryl group such as an oleenyloxy group (C ₁₃ ) and an oxygen atom is exemplified.

The monovalent aromatic hydrocarbon group typically includes an aryl group.
Examples of the aryl group include a phenyl group (C ₆ ), a naphthyl group (C ₁₀ ), an anthryl group (C ₁₄ ), a biphenyl group (C ₁₂ ), a phenanthryl group (C ₁₄ ), and a fluorenyl group (C ₁₃ ). . Examples of the divalent aromatic hydrocarbon group include an arylene group in which one hydrogen atom is further removed from the aryl group exemplified herein.

  The aromatic hydrocarbon group may also have a substituent. Although such a substituent is defined each time, a halogen atom, an alkoxy group, an acyl group, an alkyl group, and an aryloxy group can be mentioned. Among these, the alkyl group is the same as those exemplified as the chain aliphatic hydrocarbon group, and among the substituents optionally present in the aromatic hydrocarbon group, those other than the alkyl group are aliphatic hydrocarbon groups. The same thing as what was illustrated as a substituent of is included.

［式（Ｉ）中、
Ｒ^１は、置換基を有してもよい炭素数６〜１８の芳香族炭化水素基を表す。
Ｒ^２は、酸分解性基を表す。
Ｒ^３は、水素原子又はヒドロキシ基を表す。
Ｘ^１及びＸ^２は、それぞれ独立に、式（ａ−ｇ１）

（式（ａ−ｇ１）中、
ｓは０〜２の整数を表す。
Ａ^１０及びＡ^１１は、それぞれ独立に、炭素数１〜５の脂肪族炭化水素基を表す。
ｓが２のとき、複数存在するＡ^１０は、互いに同一であっても異なっていてもよい。
Ｘ^１０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。
ｓが２のとき、複数存在するＸ^１０は、互いに同一であっても異なっていてもよい。）
で表される基を表す。
ｍ１は１又は２を表し、ｍ２は０又は１を表す。但し、ｍ１＋ｍ２＝２の関係を満たす。
ｍ１が２の時、複数存在するＸ^１は互いに同一であっても異なっていてもよく、複数存在するＲ^２は互いに同一であっても異なっていてもよい。
Ａ⁻は、有機アニオンを表す。］
以下の説明において、塩（Ｉ）から、有機アニオン（Ａ⁻）を除去してなる正電荷を有するものを、場合により「有機カチオン」という。 <Salt (I)>
As described above, the salt (I) is represented by the formula (I).

[In the formula (I),
R ¹ represents an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent.
R ² represents an acid-decomposable group.
R ³ represents a hydrogen atom or a hydroxy group.
X ¹ and X ² each independently represent the formula (a-g1)

(In the formula (a-g1),
s represents the integer of 0-2.
A ¹⁰ and A ¹¹ each independently represent an aliphatic hydrocarbon group having 1 to 5 carbon atoms.
When s is 2, the plurality of A ¹⁰ may be the same as or different from each other.
X ¹⁰ represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
When s is 2, a plurality of X ¹⁰ may be the same as or different from each other. )
Represents a group represented by
m1 represents 1 or 2, and m2 represents 0 or 1. However, the relationship of m1 + m2 = 2 is satisfied.
When m1 is 2, a plurality of X ¹ may be the same or different, and a plurality of R ² may be the same or different.
A ⁻ represents an organic anion. ]
In the following description, what has a positive charge formed by removing the organic anion (A ⁻ ) from the salt (I) is sometimes referred to as “organic cation”.

First, the organic cation constituting the salt (I) will be described.
R ¹ represents an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent. Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, and an anthryl group. Among them, a phenyl group and a naphthyl group are preferable, and a phenyl group is more preferable. Examples of the substituent include an aliphatic hydrocarbon group having 1 to 12 carbon atoms and a hydroxy group. Among them, an alkyl group having 1 to 6 carbon atoms is preferable, and an alkyl group having 1 to 4 carbon atoms is more preferable.

［式（１）中、
Ｒ^a1、Ｒ^ａ２及びＲ^a3（Ｒ^a1〜Ｒ^a3）は、それぞれ独立に、炭素数１〜８のアルキル基又は炭素数３〜２０の脂環式炭化水素基を表すか、Ｒ^a1及びＲ^a2は互いに結合して炭素数２〜２０の２価の炭化水素基を形成する。＊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１価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’は互いに結合して炭素数２〜２０の２価の炭化水素基を形成する。該１価の炭化水素基及び該２価の炭化水素基を構成するメチレン基は、酸素原子又は硫黄原子に置き換わってもよい。＊は結合手を表す。］ <Acid-decomposable group>
R ² represents an acid-decomposable group. The “acid-decomposable group” means a group that has a leaving group and forms a hydrophilic group (for example, a hydroxy group or a carboxy group) by leaving the leaving group upon contact with an acid. Examples of the acid-decomposable group include a group represented by the formula (1) (hereinafter, sometimes referred to as “acid-decomposable group (1)”), a group represented by the formula (2), and the case where “ It is referred to as “acid-decomposable group (2)”. ) And the like.

[In Formula (1),
Or which R ^{a1, R a2} and a R ^a3 (R ^a1 ~R ^a3) each independently represents an alicyclic hydrocarbon group of the alkyl group or 3 to 20 carbon atoms having 1 to 8 carbon atoms, R ^a1 and R ^a2 combine with each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms. * Represents a bond. ]

[In Formula (2),
R ^{a1 ′} and R ^{a2 ′} each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms, and R ^{a3 ′} represents a hydrocarbon group having 1 to 20 carbon atoms, or R ^{a3 ′ a2 ′} and R ^{a3 ′} combine with each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms. The monovalent hydrocarbon group and the methylene group constituting the divalent hydrocarbon group may be replaced with an oxygen atom or a sulfur atom. * Represents a bond. ]

The alkyl groups and alicyclic hydrocarbon groups of R ^{a1 to} R ^a3 of the acid-decomposable group (1) include those already exemplified in the respective carbon number ranges. However, carbon number of this alicyclic hydrocarbon group becomes like this. Preferably it is the range of 3-16.

When R ^a1 and R ^a2 are bonded to each other to form a divalent hydrocarbon group, the group represented by —C (R ^a1 ) (R ^a2 ) (R ^a3 ) is any of the following groups: This is the case. The carbon number of the divalent hydrocarbon group is preferably in the range of 3-12.

Examples of the acid-decomposable group (1) include a 1,1-dialkylalkoxycarbonyl group (in the formula (1), groups in which R ^{a1 to} R ^a3 are alkyl groups, preferably a tert-butyl group), 2-alkyl An adamantane-2-yloxycarbonyl group (in formula (1), R ^a1 and R ^a2 combine to form an adamantyl ring, 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).

Examples of the R ^{a1 ′} and R ^{a2 ′} hydrocarbon groups of the acid-decomposable group (2) include an alkyl group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. Among these groups, the same groups are included in the range having 20 or less carbon atoms. However, at least one of R ^{a1 ′} and R ^{a2 ′} is preferably a hydrogen atom.

Specific examples of the acid-decomposable group (2) include the following groups.

As described above, the acid-decomposable group (1) and the acid-decomposable group preferable as R ² have been described. Of these, R ² is more preferably the acid-decomposable group (1).

（式（ａ−ｇ１）中、
ｓは０〜２の整数を表す。
Ａ^１０及びＡ^１１は、それぞれ独立に、炭素数１〜５の脂肪族炭化水素基を表す。
ｓが２のとき、複数存在するＡ^１０は、互いに同一であっても異なっていてもよい。
Ｘ^１０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。
ｓが２のとき、複数存在するＸ^１０は、互いに同一であっても異なっていてもよい。） X ¹ and X ² each independently represent a group represented by the formula (a-g1) (hereinafter sometimes referred to as “group (a-g1)”).

(In the formula (a-g1),
s represents the integer of 0-2.
A ¹⁰ and A ¹¹ each independently represent an aliphatic hydrocarbon group having 1 to 5 carbon atoms.
When s is 2, the plurality of A ¹⁰ may be the same as or different from each other.
X ¹⁰ represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
When s is 2, a plurality of X ¹⁰ may be the same as or different from each other. )

Aliphatic hydrocarbon group A ¹⁰ and A ¹¹ are members independently is typically a alkanediyl group. The alkanediyl group includes those already exemplified in the range of 1 to 5 carbon atoms.
Group (a-g1), like the X ^10, an oxygen atom, a carbonyl group, a divalent group containing an atom or an atomic group such as a carbonyl group or an oxycarbonyl group.
When the group (a-g1) is s = 0, the alkanediyl group described above can be used.

If s is 1 or 2, group (a-g1), like the X ^10, is an oxygen atom, a carbonyl group, a divalent group containing an atom or an atomic group such as a carbonyl group or an oxycarbonyl group . Specific examples of these are shown below.

などが挙げられる（＊は結合手を表す）。 As the group having an oxygen atom (a-g1),

(* Represents a bond).

などが挙げられる（＊は結合手を表す）。 As the group (a-g1) having a carbonyl group,

(* Represents a bond).

などが挙げられる（＊は結合手を表す）。 As the group (a-g1) having a carbonyloxy group,

(* Represents a bond).

などが挙げられる（＊は結合手を表す）。 As the group having an oxycarbonyl group (a-g1),

(* Represents a bond).

Specific examples of the group (a-g1) have been described above. Among these, s is 0 and A ¹¹ is an alkanediyl group having 1 to 5 carbon atoms (more preferably, having 1 to 4 carbon atoms). alkanediyl group) in a group, i.e., the alkanediyl group (more preferably a methylene group or an ethylene group), or, s is 1, alkanediyl having 1 to 5 carbon atoms a ¹⁰ and a ¹¹ are each independently A group in which X ¹⁰ is an oxygen atom is preferable as X ¹ . On the other hand, X ² is preferably an alkanediyl group of 1 to 5 carbon atoms, more preferably an alkanediyl group of 1 to 4 carbon atoms, more preferably methylene group and ethylene group.

ここで、Ｘ^３は炭素数１〜３のアルカンジイル基であり、メチレン基及びエチレン基が好ましい。 When R ² is an acid-decomposable group (1), X ¹ is s is 1, A ¹⁰ and A ¹¹ are each independently an alkanediyl group having 1 to 5 carbon atoms, and X ¹⁰ is oxygen The group (a-g1) which is an atom is preferable. Specific examples of the group represented by * -X ¹ -R ² (* is a bond with a sulfur atom) in this case are as follows.

Here, X ³ is an alkanediyl group having 1 to 3 carbon atoms, a methylene group and an ethylene group are preferable.

On the other hand, when R ² is an acid-decomposable group (2), X ¹ is preferably an alkanediyl group having 1 to 5 carbon atoms. Specific examples of the group represented by * -X ¹ -R ² (* is a bond with a sulfur atom) in this case are as follows.

In the above, specific examples of each of R ¹ , R ² , X ¹ and X ² have been described regarding the organic cation constituting the salt (I). Here, specific examples of the organic cation constituting the salt (I) Indicates.

［式（Ｉ−Ａ）中、
Ｑ¹及びＱ²は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^b1は、単結合又は２価の炭素数１〜１７の飽和炭化水素基を表し、該２価の飽和炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｙは、置換基を有していてもよい炭素数１〜１８のアルキル基又は置換基を有していてもよい炭素数３〜１８の脂環式炭化水素基を表し、該アルキル基及び該脂環式炭化水素基を構成するメチレン基は、酸素原子、スルホニル基又はカルボニル基で置き換わっていてもよい。］ Next, the organic anion (A ⁻ ) constituting the salt (I) will be described.
The organic anion is selected from the group consisting of a sulfonate anion, a sulfonylimide anion, a sulfonylmethide anion, and a carboxylate anion. Among these, a sulfonate anion is preferable, and a sulfonate anion represented by the formula (IA) is more preferable.

[In the formula (IA),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a single bond or a divalent saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group constituting the divalent saturated hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
Y represents an alkyl group having 1 to 18 carbon atoms which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent. The methylene group constituting the alicyclic hydrocarbon group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group. ]

The perfluoroalkyl group of Q ¹ and Q ² corresponds to an alkyl group having 1 to 6 carbon atoms already exemplified, in which all hydrogen atoms contained in the alkyl group are replaced with fluorine atoms. Specific examples include a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, and a perfluorohexyl group. Here, the perfluoroalkyl group has been described with specific examples thereof, but Q ¹ and Q ² are each independently preferably a fluorine atom or a trifluoromethyl group, and both Q ¹ and Q ² are more preferably a fluorine atom. .

The divalent aliphatic saturated hydrocarbon group of L ^b1 is an alkanediyl group exemplified above in the range of 1 to 17 carbon atoms, and any of the above-mentioned formulas (KA-1) to (KA-22). Examples thereof include a divalent alicyclic hydrocarbon group obtained by removing two hydrogen atoms from a cyclic hydrocarbon. The alkanediyl group may be linear or branched. The divalent aliphatic saturated hydrocarbon group of L ^b1 is a divalent combination of an alkanediyl group and a divalent alicyclic hydrocarbon group, as long as it has a carbon number of 17 or less. It may be a group.

式（ｂ１−１）〜式（ｂ１−７）中、
Ｌ^b2は、単結合又は炭素数１〜１５の２価の脂肪族飽和炭化水素基を表す。
Ｌ^b3は、単結合又は炭素数１〜１２の２価の脂肪族飽和炭化水素基を表す。
Ｌ^b4は、炭素数１〜１３の２価の２価の脂肪族飽和炭化水素基を表す。但しＬ^b3及びＬ^b4の合計炭素数の上限は１３である。
Ｌ^b５は、単結合又は炭素数１〜１４の２価の脂肪族飽和炭化水素基を表す。
Ｌ^b６は、炭素数１〜１５の２価の脂肪族飽和炭化水素基を表す。但しＬ^b5及びＬ^b6の合計炭素数の上限は１５である。
Ｌ^b７は、単結合又は炭素数１〜１５の２価の２価の脂肪族飽和炭化水素基を表す。
Ｌ^b８は、炭素数１〜１６の２価の２価の脂肪族飽和炭化水素基を表す。但しＬ^b７及びＬ^b８の合計炭素数の上限は１６である。
Ｌ^b9は、単結合又は炭素数１〜１３の２価の脂肪族飽和炭化水素基を表す。
Ｌ^b10は、炭素数１〜１４の２価の２価の脂肪族飽和炭化水素基を表す。但しＬ^b9及びＬ^b10の合計炭素数の上限は１４である。
Ｌ^b11及びＬ^b12は、単結合又は炭素数１〜１１の２価の脂肪族飽和炭化水素基を表す。
Ｌ^b13は、炭素数１〜１２の２価の脂肪族飽和炭化水素基を表す。但しＬ^b11、Ｌ^b12及びＬ^b13の合計炭素数の上限は１２である。
Ｌ^b14及びＬ^b15は、それぞれ独立に、単結合又は炭素数１〜１３の脂肪族飽和炭化水素基を表す。
Ｌ^b16は、炭素数１〜１４の脂肪族飽和炭化水素基を表す。但しＬ^b14、Ｌ^b15及びＬ^b16の合計炭素数の上限は１４である。 Specific examples of the group in which the methylene group constituting the divalent aliphatic saturated hydrocarbon group of L ^b1 is replaced with an oxygen atom or a carbonyl group include, for example, the following formulas (b1-1) to (b1-7) ) Or a group represented by any of the above. L ^b1 is preferably a group represented by any one of formulas (b1-1) to (b1-4), more preferably represented by formula (b1-1) or formula (b1-3). It is a group. In addition, * which shows the bond in Formula (b1-1)-Formula (b1-7) has described the left and right according to Formula (IA), and the left bond is C (Q ¹ ) It is bonded to the carbon atom of (Q ² ). The same applies to specific examples of formula (b1-1) to formula (b1-7) shown below.

In formula (b1-1) to formula (b1-7),
L ^b2 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b3 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b4 represents a divalent divalent aliphatic saturated hydrocarbon group having 1 to 13 carbon atoms. However, the upper limit of the total carbon number of L ^b3 and L ^b4 is 13.
L ^b5 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms.
L ^b6 represents a divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms. However, the upper limit of the total carbon number of L ^b5 and L ^b6 is 15.
L ^b7 represents a single bond or a divalent divalent aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b8 represents a divalent divalent aliphatic saturated hydrocarbon group having 1 to 16 carbon atoms. However, the upper limit of the total carbon number of L ^b7 and L ^b8 is 16.
L ^b9 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 13 carbon atoms.
L ^b10 represents a divalent divalent aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms. However, the upper limit of the total carbon number of L ^b9 and L ^b10 is 14.
L ^b11 and L ^{b12 each} represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 11 carbon atoms.
L ^b13 represents a divalent aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms. However, the upper limit of the total carbon number of L ^b11 , L ^b12 and L ^b13 is 12.
L ^b14 and L ^b15 each independently represent a single bond or an aliphatic saturated hydrocarbon group having 1 to 13 carbon atoms.
L ^b16 represents an aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms. However, the upper limit of the total carbon number of L ^b14 , L ^b15 and L ^b16 is 14.

Examples of the divalent group represented by the formula (b1-1) include the following.

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

Examples of the divalent group represented by the formula (b1-3) include the following.

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

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

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

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

When Y is an alkyl group, the alkyl group includes those already exemplified in the range of 1 to 18 carbon atoms. Among them, an alkyl group having 1 to 6 carbon atoms is preferable. Further, the methylene group constituting the alkyl group may be replaced with an oxygen atom, a carbonyl group or a sulfonyl group.
When Y is an alicyclic hydrocarbon group, including those already exemplified in the range of 3 to 18 carbon atoms, the methylene group constituting the alicyclic hydrocarbon group is an oxygen atom, a carbonyl group or a sulfonyl group May be replaced. Among these, as the alicyclic hydrocarbon group for Y, groups represented by the following formulas (Y1) to (Y11) are preferable, and the methylene group constituting the alicyclic hydrocarbon group is an oxygen atom, As the group replaced with a carbonyl group or a sulfonyl group, groups represented by the following formulas (Y12) to (Y26) are preferable.

  Especially, it is preferably a group represented by any one of formulas (Y1) to (Y19), more preferably represented by formula (Y11), formula (Y14), formula (Y15) or formula (Y19). And more preferably a group represented by formula (Y11) or formula (Y14).

Examples of the substituent that the alkyl group of Y and the alicyclic hydrocarbon group optionally have include, for example, a halogen atom; a hydroxy group; a C 1-12 alkoxy group optionally having a halogen atom or a hydroxy group; Group, alicyclic hydrocarbon group, halogen atom or hydroxy group optionally having 6 to 18 carbon atoms, alkyl group, halogen atom or hydroxy group An aralkyl group having 7 to 21 carbon atoms, an acyl group having 2 to 4 carbon atoms, a glycidyloxy group, or — (CH ₂ ) _j2 —O—CO—R ^b1 group (wherein R ^b1 is an alkyl group having 1 to 16 carbon atoms) Represents an alicyclic hydrocarbon group having 3 to 16 carbon atoms or an aromatic hydrocarbon group having 6 to 18 carbon atoms, j2 represents an integer of 0 to 4). When Y is an alkyl group, it may have an alicyclic hydrocarbon group having 3 to 16 carbon atoms as a substituent, and when Y is an alicyclic hydrocarbon group, it has an alkyl group as a substituent. You may do it.

The halogen atom may be any of those already exemplified. .
Although the said alkoxy group contains what was already illustrated in the range of C1-C12, a C1-C6 alkoxy group is preferable.
Examples of the aromatic hydrocarbon group include those already exemplified in the range of 1 to 18 carbon atoms. Examples of the aromatic hydrocarbon group having a substituent include p-methylphenyl group, p-tert-butylphenyl group, p-adamantylphenyl group, tolyl group, xylyl group, cumenyl group, mesityl group, 2,6- Examples thereof include a diethylphenyl group and 2-methyl-6-ethylphenyl.
The aralkyl group and the acyl group include those already exemplified in the respective carbon number ranges.

Specific examples in the case where Y is an alicyclic hydrocarbon group having a substituent include the following.

  Y is preferably an adamantyl group which may have a substituent, and more preferably an adamantyl group or an oxoadamantyl group.

式（ｂ１−１−１）〜式（ｂ１−１−９）で表される有機アニオンにおいて、Ｌ^ｂ２は前記と同じ意味であり、Ｒ^ｂ２及びＲ^ｂ３は、それぞれ独立に炭素数１〜４のアルキル基（好ましくは、メチル基）を表す。ここに示す有機アニオンは、特開２０１０−２０４６４６号公報に記載されている。 The organic anion represented by the formula (IA) has been described with reference to preferred examples of Q ¹ , Q ² , L ^b1 and Y. Here, the organic anion represented by the more preferred formula (IA) When an anion is mentioned, what is each represented by the following formula | equation (b-1-1)-a formula (b-1-9) will be mentioned.

In the organic anions represented by formula (b1-1-1) to formula (b1-1-9), L ^b2 has the same meaning as described above, and R ^b2 and R ^b3 each independently have 1 to 4 carbon atoms. Represents an alkyl group (preferably a methyl group). The organic anions shown here are described in JP2010-204646A.

More specifically, preferred organic anions are as follows.

  As mentioned above, although the salt (I) was divided into the organic cation and the organic anion constituting it, the salt (I) can be arbitrarily combined. This combination is represented by the organic cation represented by the formula (Ic-1) to the formula (Ic-60) and the formula (Ia-1) to the formula (Ia-7). It represents with the combination with an organic anion, and it summarizes in Tables 1-10.

From Table 1 to Table 10, the more preferable salt (I) among the salts (I) represented by the combination of the organic anion and the organic cation is specifically shown as follows.

Next, the production method of the salt (I) is as follows:
A salt (I) [a salt (I) represented by the formula (I1) (salt (I1))] when R ² is an acid-decomposable group (1) and m1 is 1,
The description will be divided into salt (I) [salt (I) represented by formula (I2) (salt (I2))] when R ² is an acid-decomposable group (1) and m1 is 2. .

（式中、Ｘ^４及びＸ^５はアルカンジイル基であり、その合計炭素数は２〜４の範囲である。その他の符号は、前記と同じ意味を表す。）
この反応で用いる溶剤は、アセトニトリルなどである。
塩基触媒としては、トリエチルアミンなどが用いられる。
式（Ｉ１−ａ）で表される化合物は、以下で表される化合物等が挙げられる。

The salt (I1) is obtained by reacting a compound represented by the formula (I1-a) (equivalent to a salt represented by the formula (I1-b)) and a salt represented by the formula (I1-b) with a base catalyst. It can manufacture by making it react in a solvent in presence. This reaction is expressed in the form of a reaction formula as follows.

(In the formula, X ⁴ and X ⁵ are alkanediyl groups, and the total carbon number thereof is in the range of 2 to 4. The other symbols represent the same meaning as described above.)
A solvent used in this reaction is acetonitrile or the like.
As a base catalyst, triethylamine or the like is used.
Examples of the compound represented by the formula (I1-a) include compounds represented by the following.

（式中、全ての符号は、それぞれ前記と同じ意味を表す。）
この反応で用いる溶剤は、モノクロロベンゼンなどである。
触媒としては、安息香酸銅（ＩＩ）などが用いられる。
式（Ｉ１−ｃ）で表される塩としては、以下で表される化合物などが挙げられる。

式（Ｉ−ｄ）で表される化合物は、以下で表される化合物などが挙げられる。

The salt represented by the formula (I1-b) is obtained by reacting the salt represented by the formula (I1-c) with the compound represented by the formula (I1-d) in the presence of a catalyst in a solvent. Can be manufactured. This reaction is expressed in the form of a reaction formula as follows.

(In the formula, all symbols have the same meaning as described above.)
A solvent used in this reaction is monochlorobenzene or the like.
As the catalyst, copper (II) benzoate or the like is used.
Examples of the salt represented by the formula (I1-c) include compounds represented by the following.

Examples of the compound represented by the formula (Id) include the following compounds.

（式中、全ての符号は、前記と同義である。）
この反応の反応条件は、式（Ｉ１−ａ）で表される化合物を、式（Ｉ２−ｂ）で表される塩に対して、略２当量以上用いるほかは、塩（Ｉ１）の製造条件と同様である。
式（Ｉ２−ｂ）で表される塩は、式（Ｉ１−ｂ）で表される塩と同様にして製造することができる。 On the other hand, the salt (I2) can be produced by reacting the compound represented by the formula (I1-a) and the salt represented by the formula (I2-b) in the presence of a base catalyst in a solvent. .

(In the formula, all symbols are as defined above.)
The reaction conditions for this reaction are the same as those for the production of the salt (I1) except that the compound represented by the formula (I1-a) is used in an amount of about 2 equivalents or more with respect to the salt represented by the formula (I2-b). It is the same.
The salt represented by the formula (I2-b) can be produced in the same manner as the salt represented by the formula (I1-b).

<Acid generator other than salt (I)>
The present resist composition obtained by using a single kind or a plurality of kinds of salts (I) as an acid generator can produce a resist pattern with an excellent focus margin. However, the present resist composition contains a salt (I). Other known acid generators other than the above can also be used. The acid generator other than the salt (I) may be an ionic acid generator or a nonionic generator, but is preferably an ionic acid generator. Hereinafter, the acid generator other than the salt (I) that can be contained in the resist composition is sometimes referred to as “acid generator (B)”.

As an acid generator (B), what is represented by either of Formula (B1-1)-Formula (B1-20) is mentioned, for example. Among them, those containing a triphenylsulfonium cation and a tolylsulfonium cation are preferable. Formula (B1-1), Formula (B1-2), Formula (B1-3), Formula (B1-6), and Formula (B1-7) And salts represented by formula (B1-11), formula (B1-12), formula (B1-13) and formula (B1-14), respectively.

<Resin (A)>
As described above, the resin (A) is insoluble or hardly soluble in an alkaline aqueous solution and has a characteristic that it becomes soluble in an alkaline aqueous solution by the action of an acid (hereinafter, sometimes referred to as “acidic action characteristic”). Note that “can be dissolved in an alkaline aqueous solution by the action of an acid” means “insoluble or hardly soluble in an alkaline aqueous solution before contact with an acid, but soluble in an alkaline aqueous solution after contact with an acid”. Means.

  The resin (A) having acid action characteristics has an acid-decomposable group in the molecule. The acid-decomposable group has the same concept as described for the acid-decomposable group of the salt (I). The acid-decomposable group (1) and the acid-decomposable group (2) are also preferable as the acid-decomposable group of the resin (A). Such a resin (A) is a monomer having an acid labile group (hereinafter, this monomer is sometimes referred to as “monomer (a1)”, and the structural unit derived from the monomer (a1) is referred to as “structural unit (a1)”. Can be produced by polymerization. In producing the resin (A) having acid action characteristics, the monomer (a1) may be used alone, or two or more kinds may be used in combination.

The monomer (a1) is preferably a monomer having an acid-decomposable group and a carbon-carbon double bond, and more preferably a (meth) acrylic monomer having an acid-decomposable group.
Especially, the monomer (a1) which has an acid-decomposable group (1) and / or an acid-decomposable group (2) is preferable, and has an acid-decomposable group (1) and / or an acid-decomposable group (2) (meta ) Acrylic monomers are particularly preferred.

  Of the (meth) acrylic monomers having an acid-decomposable group, the monomer (a1) having an alicyclic hydrocarbon group having 5 to 20 carbon atoms is preferred. Since the resin (A) obtained using such a monomer (a1) has a bulky structure such as an alicyclic hydrocarbon group, the resist composition containing the resin (A) The resolution tends to be better.

［式（ａ１−１）中、
Ｌ^a1は、酸素原子又は＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−（ｋ１は１〜７の整数を表し、＊はカルボニル基との結合手を表す。）で表される基を表す。
Ｒ^a4は、水素原子又はメチル基を表す。
Ｒ^a6は、炭素数１〜１０の脂肪族炭化水素基を表す。
ｍ１は０〜１４の整数を表す。
式（ａ１−２）中、
Ｌ^a2は、酸素原子又は＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−（ｋ１は前記と同義である。）で表される基を表す。
Ｒ^a5は、水素原子又はメチル基を表す。
Ｒ^a7は、炭素数１〜１０の脂肪族炭化水素基を表す。
ｎ１は０〜１０の整数を表す。
ｎ１’は０〜３の整数を表す。］ <Preferred structural unit (a1)>
The resin (A) having a suitable structural unit (a1) obtained by using the monomer (a1) having such an alicyclic hydrocarbon group will be further described in detail. Among the resins (A), a structural unit represented by the formula (a1-1) (hereinafter sometimes referred to as “structural unit (a1-1)”) or a structural unit represented by the formula (a1-2) A resin (A) having (hereinafter referred to as “structural unit (a1-2)” in some cases) is preferable. Such resin (A) may have the structural unit (a1-1) as a single species, may have a plurality of types, or may have the structural unit (a1-2) as a single species. In addition, a plurality of types may be included, and the structural unit (a1-1) and the structural unit (a1-2) may be combined.

[In the formula (a1-1),
L ^a1 represents an oxygen atom or a group represented by * —O— (CH ₂ ) _k1 —CO—O— (k1 represents an integer of 1 to 7, and * represents a bond to a carbonyl group). Represent.
R ^a4 represents a hydrogen atom or a methyl group.
R ^a6 represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms.
m1 represents the integer of 0-14.
In formula (a1-2),
L ^a2 represents an oxygen atom or a group represented by * —O— (CH ₂ ) _k1 —CO—O— (k1 is as defined above).
R ^a5 represents a hydrogen atom or a methyl group.
R ^a7 represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms.
n1 represents an integer of 0 to 10.
n1 ′ represents an integer of 0 to 3. ]

L ^a1 and L ^a2 are preferably an oxygen atom or a group represented by * —O— (CH ₂ ) _k1 —CO—O—, wherein k1 is an integer of 1 to 4, more preferably an oxygen atom. or * -O-CH ₂ -CO-O- and, still more preferably an oxygen atom.
R ^a4 and R ^a5 are preferably methyl groups.
Of the aliphatic hydrocarbon groups of R ^a6 and R ^a7 , preferably an alkyl group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 10 carbon atoms, and within the range of the upper limit of the carbon number, Includes the same as those already exemplified. The aliphatic hydrocarbon groups for R ^a6 and R ^a7 are each independently preferably an alkyl group having 8 or less carbon atoms or an alicyclic hydrocarbon group having 8 or less carbon atoms, more preferably an alkyl group having 6 or less carbon atoms. Or it is an alicyclic hydrocarbon group having 6 or less carbon atoms.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 ′ is preferably 0 or 1.

As the structural unit (a1-1), structural units represented by any of the following formulas (a1-1-1) to (a1-1-8) are preferable, and the structural units (a1-1-1) to (a1-1-1) The structural unit represented by any one of (a1-1-4) is more preferable.

  Examples of the monomer (a1) from which these structural units (a1-1) can be derived include those described in JP-A No. 2010-204646.

On the other hand, as the structural unit (a1-2), a structural unit represented by any of the following formulas (a1-2-1) to (a1-2-12) is preferable. Among these, structural units represented by formula (a1-2-1) to formula (a1-2-4) and formula (a1-2-9) to formula (a1-2-10) are more preferable, The structural unit represented by the formula (a1-2-3) or (a1-2-9) is more preferable.

  Examples of the monomer (a1) capable of deriving the structural unit (a1-2) include 1-ethylcyclopentan-1-yl (meth) acrylate, 1-ethylcyclohexane-1-yl (meth) acrylate, and 1-ethyl. Examples include cycloheptan-1-yl (meth) acrylate, 1-methylcyclopentan-1-yl (meth) acrylate, and 1-isopropylcyclopentan-1-yl (meth) acrylate.

  When the resin (A) has the structural unit (a1-1) and / or the structural unit (a1-2), the total content thereof is based on the total structural unit (100 mol%) of the resin (A). The range of 10 to 95 mol% is preferable, the range of 15 to 90 mol% is more preferable, the range of 20 to 85 mol% is more preferable, and the range of 20 to 60 mol% is particularly preferable. When the structural unit (a1) has a structural unit (a1) having an adamantyl group (particularly preferably, the structural unit (a1-1)), the total of the structural units (a1) in the resin (A) The structural unit (a1) having an adamantyl group is preferably 15 mol% or more with respect to (100 mol%). With such a content ratio, the resin (A) having the structural unit (a1) having an adamantyl group tends to have good dry etching resistance of a resist pattern produced from the resist composition containing the resin (A). There is. In addition, in order to make the total content rate of a structural unit (a1-1) and / or a structural unit (a1-2) into the above-mentioned range, when manufacturing resin (A), it is with respect to the usage-amount of all monomers. What is necessary is just to adjust the usage-amount of the monomer which induces | guides | derives a structural unit (a1-1) and / or a structural unit (a1-2).

  Among the structural units of the resin (A), the structural unit (a1-1) and the structural unit (a1-2) that are preferable for the resin (A) to have acid action characteristics are described in detail. It is particularly preferable that the resin (A) has the unit (a1-1).

  The resin (A) may have a structural unit (a1) other than the structural unit (a1-1) and the structural unit (a1-2) which are suitable structural units (a1). Hereinafter, the structural unit (a1) other than the structural unit (a1-1) and the structural unit (a1-2) will be described by showing a monomer (a1) that derives the structural unit (a1).

式（ａ１−３）中、
Ｒ^a9は、水素原子、置換基（例えばヒドロキシ基）を有していてもよい炭素数１〜３の脂肪族炭化水素基、カルボキシ基、シアノ基、又は−ＣＯＯＲ^a13で表される基を表し、Ｒ^a13は、炭素数１〜８の脂肪族炭化水素基を表し、該脂肪族炭化水素基に含まれる水素原子はヒドロキシ基などに置換されていてもよく、該脂肪族炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。Ｒ^a10、Ｒ^a11及びＲ^a12は、それぞれ独立に、炭素数１〜１２の脂肪族炭化水素基を表すか、或いはＲ^a10及びＲ^a11は互いに結合して環を形成している。該脂肪族炭化水素基及に含まれる水素原子はヒドロキシ基などで置換されていてもよく、該脂肪族炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。 The resin (A) may have a structural unit (a1) derived from a monomer represented by the following formula (a1-3) (hereinafter sometimes referred to as “monomer (a1-3)”). . Since the resin (A) having the structural unit (a1) derived from the monomer (a1-3) contains a rigid norbornane ring in its main chain, the present resist containing such a resin (A) The composition tends to produce a resist pattern having excellent dry etching resistance.

In formula (a1-3),
R ^a9 represents a hydrogen atom, an aliphatic hydrocarbon group having 1 to 3 carbon atoms which may have a substituent (for example, a hydroxy group), a carboxy group, a cyano group, or a group represented by —COOR ^a13. , R ^a13 represents an aliphatic hydrocarbon group having 1 to 8 carbon atoms, and a hydrogen atom contained in the aliphatic hydrocarbon group may be substituted with a hydroxy group or the like, constituting the aliphatic hydrocarbon group The methylene group may be replaced by an oxygen atom or a carbonyl group. R ^a10 , R ^a11 and R ^a12 each independently represents an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or R ^a10 and R ^a11 are bonded to each other to form a ring. The hydrogen atom contained in the aliphatic hydrocarbon group may be substituted with a hydroxy group or the like, and the methylene group constituting the aliphatic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.

The aliphatic hydrocarbon group which may have a substituent of R ^a9 is typically an alkyl group which may have a substituent, and among these alkyl groups, an alkyl having no substituent The group includes those already exemplified in the range of 1 to 8 carbon atoms. Examples of the substituent, particularly the aliphatic hydrocarbon group (alkyl group) having a hydroxy group include a hydroxymethyl group and a 2-hydroxyethyl group. ^Examples of R ^a13 include a methyl group, an ethyl group, a propyl group, a 2-oxo-oxolan-3-yl group, and a 2-oxo-oxolan-4-yl group.

The aliphatic hydrocarbon groups of R ^{a10 to} R ^a12 are also typically alkyl groups, and specific examples thereof are the same as those of R ^a9 . The ring formed by combining R ^a10 and R ^a11 together with the carbon atom to which they are bonded includes a cyclohexane ring and an adamantane ring.

As a monomer (a1-3), what was described in Unexamined-Japanese-Patent No. 2010-204646 is used, for example. Among these, monomers represented by the following formula (a1-3-1), formula (a1-3-2), formula (a1-3-3) and formula (a1-3-4) are preferable, The monomer represented by the formula (a1-3-2) or (a1-3-4) is more preferable, and the monomer represented by the formula (a1-3-2) is more preferable.

  When the resin (A) has a structural unit derived from the monomer (a1-3), the content is preferably in the range of 10 to 95 mol% with respect to the total structural unit of the resin (A). The range of 90 mol% is more preferable, and the range of 20 to 85 mol% is more preferable.

［式（ａ１−４）中、
Ｒ¹⁰は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
ｌ^ａは０〜４の整数を表す。
Ｒ¹¹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のアシル基、炭素数２〜４のアシルオキシ基、アクリロイル基又はメタクリロイル基を表し、ｌ^ａが２以上である場合、複数のＲ¹¹は互いに同一であっても異なってもよい。
Ｒ¹²及びＲ¹³はそれぞれ独立に、水素原子又は炭素数１〜１２の炭化水素基を表す。
Ｘ^a2は、置換基を有していてもよい炭素数１〜１７の脂肪族炭化水素基又は単結合を表し、該脂肪族炭化水素基を構成するメチレン基は、酸素原子、硫黄原子、カルボニル基、スルホニル基又は−Ｎ（Ｒ^ｃ）−（ただし、Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す）で表される基に置き換わっていてもよい。
Ｙ^a3は、置換基を有していてもよい炭素数１〜１８の炭化水素基を表す。］ The resin (A) may have a structural unit (a1) derived from a monomer represented by the following formula (a1-4) (hereinafter sometimes referred to as “monomer (a1-4)”).

[In the formula (a1-4),
R ¹⁰ represents an alkyl group having 1 to 6 carbon atoms which may have a halogen atom, a hydrogen atom or a halogen atom.
l ^a represents an integer of 0 to 4;
R ¹¹ 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 acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an acryloyl group, or methacryloyl. In the case where l ^a is 2 or more, a plurality of R ¹¹ may be the same as or different from each other.
R ¹² and R ¹³ each independently represent a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms.
X ^a2 represents an ^optionally substituted aliphatic hydrocarbon group having 1 to 17 carbon atoms or a single bond, and the methylene group constituting the aliphatic hydrocarbon group includes an oxygen atom, a sulfur atom, a carbonyl A group, a sulfonyl group, or a group represented by —N (R ^c ) — (wherein R ^c represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) may be substituted.
Y ^a3 represents an ^optionally substituted hydrocarbon group having 1 to 18 carbon atoms. ]

Among “an alkyl group having 1 to 6 carbon atoms which may have a halogen atom”, the alkyl group includes those already exemplified in the range of 1 to 6 carbon atoms. As the alkyl group having a halogen atom, an alkyl group having a fluorine atom is preferable. Specific examples thereof include, for example, the perfluoroalkyl group described in Q ¹ and Q ² of the organic anion constituting the salt (I). Among these, as R < ¹⁰ >, a C1-C4 alkyl group is preferable, a methyl group and an ethyl group are more preferable, and a methyl group is especially preferable.
The alkoxy group of R ¹¹ includes those already exemplified in the range of 1 to 6 carbon atoms. Among them, 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 particularly preferable. preferable.
The acyl group and acyloxy group of R ¹¹ include those already exemplified in the range of 2 to 4 carbon atoms.
The hydrocarbon groups of R ¹² and R ¹³ are those having 1 to 12 carbon atoms, and the hydrocarbon group of Y ^a3 is the aliphatic hydrocarbon group exemplified above in the range of 1 to 18 carbon atoms. Contains any of the aromatic hydrocarbon groups.
The aliphatic hydrocarbon group of X ^a2 is a divalent chain hydrocarbon group, a divalent alicyclic hydrocarbon group, or a divalent group in which a chain hydrocarbon group and an alicyclic hydrocarbon group are combined. And groups obtained by appropriately combining the groups already exemplified in the range of 1 to 17 carbon atoms.

As a monomer (a1-4), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Among these, monomers represented by any of the following formulas (a1-4-1) to (a1-4-7) are preferable, and those represented by formulas (a1-4-1) to (a1-4-5) are preferable. A monomer represented by any one is more preferable.

  When the resin (A) has a structural unit derived from the monomer (a1-4), the content is preferably in the range of 10 to 95 mol% with respect to the total structural unit of the resin (A). The range of mol% is more preferable, and the range of 20 to 85 mol% is particularly preferable.

式（ａ１−５）中、
Ｒ^３１は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｌ^３〜Ｌ^５は、酸素原子、硫黄原子又は＊−Ｏ−（ＣＨ₂）_k4−ＣＯ−Ｏ−で表される基を表す。ここで、ｋ４は１〜７の整数を表し、＊はカルボニル基（−ＣＯ−）との結合手である。
Ｚ^１’は、単結合又は炭素数１〜６のアルカンジイル基であり、該アルカンジイル基中に含まれるメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
ｓ１及びｓ１’は、それぞれ独立して、０〜４の整数を表す。 As the other monomer (a1), for example, a monomer represented by the formula (a1-5) (hereinafter sometimes referred to as “monomer (a1-5)”) may be used.

In formula (a1-5),
R ³¹ represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
L ^{3 to} L ⁵ represent an oxygen atom, a sulfur atom, or a group represented by * —O— (CH ₂ ) _k4 —CO—O—. Here, k4 represents an integer of 1 to 7, and * is a bond with a carbonyl group (—CO—).
Z ^{1 ′} is a single bond or an alkanediyl group having 1 to 6 carbon atoms, and the methylene group contained in the alkanediyl group may be replaced with an oxygen atom or a carbonyl group.
s1 and s1 ′ each independently represents an integer of 0 to 4.

In formula (a1-5), R ³¹ is preferably a hydrogen atom, a methyl group, or a trifluoromethyl group.
L ⁵ is preferably an oxygen atom.
One of L ³ and L ⁴ is preferably an oxygen atom and the other is a sulfur atom.
s1 is preferably 1.
s1 ′ is preferably an integer of 0 to 2.
Z ^{1 ′} is preferably a single bond or * —CH ₂ —CO—O—.

Examples of the monomer (a1-5) include the following monomers.

  When the resin (A) has a structural unit derived from the monomer (a1-5), the content thereof is in the range of 1 to 95 mol% with respect to all the structural units (100 mol%) of the resin (A). Is preferable, the range of 3-90 mol% is more preferable, and the range of 5-85 mol% is further more preferable.

<Acid stable structural unit>
Resin (A) is a structural unit having no acid labile group in addition to the structural unit (a1) containing an acid labile group (hereinafter referred to as “acid stable structural unit” in some cases). The derivatizable monomer is preferably referred to as “acid-stable monomer”). In the resin (A), the acid stable structural unit may have only one type, or may have a plurality of types.

  When the resin (A) has an acid stable structural unit, the content ratio of the acid stable structural unit may be determined based on the content ratio of the structural unit (a1). The ratio of the content ratio of the structural unit (a1) and the content ratio of the acid-stable structural unit is represented by [structural unit (a1)] / [acid-stable structural unit], and preferably 10 to 80 mol% / 90 It is 20 mol%, More preferably, it is 20-60 mol% / 80-40 mol%. If it does in this way, there exists a tendency for the dry etching tolerance of the resist pattern obtained from this resist composition containing resin (A) to become still better.

Next, a preferable thing is demonstrated among an acid stable structural unit.
The acid stable structural unit is preferably a structural unit having a hydroxy group or a lactone ring. An acid stable structural unit having a hydroxy group (hereinafter sometimes referred to as “acid stable structural unit (a2)”) and / or an acid stable structural unit having a lactone ring (hereinafter sometimes referred to as “acid stable structural unit (a3)”) When the resist composition containing the resin (A) is applied to a substrate, a coating film formed on the substrate or a composition layer obtained from the coating film is a substrate. Therefore, it is possible to manufacture a resist pattern with good resolution. In addition, the manufacturing method of the resist pattern using this resist composition here is mentioned later. First, the acid stable structural unit (a2) and the acid stable structural unit (a3) suitable as the acid stable structural unit will be described with specific examples.

<Acid stable structural unit (a2)>
When the acid-stable structural unit (a2) is introduced into the resin (A), a suitable acid-stable structure is used depending on the type of exposure source when producing a resist pattern from the resist composition containing the resin (A). The unit (a2) can be selected. That is, when this resist composition is used for exposure using a KrF excimer laser (wavelength: 248 nm) as an exposure source, or exposure using a high energy beam such as an electron beam or EUV light as an exposure source, an acid stable structural unit ( As a2), it is preferable to introduce an acid stable structural unit (a2-0) having a phenolic hydroxy group into the resin (A).
When using exposure using a short wavelength ArF excimer laser (wavelength: 193 nm) as an exposure source, an acid stable structural unit represented by the formula (a2-1) described later is used as a resin ( It is preferable to introduce into A). Thus, each of the acid stable structural units (a2) possessed by the resin (A) can be selected according to the exposure source used for producing the resist pattern, but the acid stable structural units possessed by the resin (A) ( a2) may have only one type of acid stable structural unit (a2) suitable for the type of exposure source, and two or more types of acid stable structural unit (a2) suitable for the type of exposure source. Or an acid stable structural unit (a2) suitable for the type of exposure source and a combination of other acid stable structural units (a2).

式（ａ２−１）中、
Ｌ^a3は、酸素原子又は＊−Ｏ−（ＣＨ₂）_k2−ＣＯ−Ｏ−（ｋ２は１〜７の整数を表し、＊はカルボニル基（−ＣＯ−）との結合手を表す。）で表される基を表す。
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の整数を表す。 One specific example of the acid stable structural unit (a2) is one represented by the following formula (a2-1) (hereinafter sometimes referred to as “acid stable structural unit (a2-1)”).

In formula (a2-1),
L ^a3 is an oxygen atom or * —O— (CH ₂ ) _k2 —CO—O— (k2 represents an integer of 1 to 7, and * represents a bond to a carbonyl group (—CO—)). Represents the group represented.
R ^a14 represents a hydrogen atom or a methyl group.
R ^a15 and R ^a16 each independently represent a hydrogen atom, a methyl group or a hydroxy group.
o1 represents an integer of 0 to 10.

L ^a3 is preferably an oxygen atom or a group represented by * —O— (CH ₂ ) _k2 —CO—O—, wherein k2 is an integer of 1 to 4, and more preferably an oxygen atom or * —O—CH ₂ —CO—O—, and more preferably an oxygen atom.
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, more preferably 0 or 1.

As an acid stable structural unit (a2-1), the following are mentioned, for example.

  As described above, the exemplified acid stable structural unit (a2-1) is derived from, for example, an acid stable monomer described in JP 2010-204646 A. Among these, the acid stable structural unit represented by any one of formula (a2-1-1), formula (a2-1-2), formula (a2-1-3), or formula (a2-1-4) Are more preferable, and an acid stable structural unit represented by the formula (a2-1-1) or (a2-1-3) is more preferable.

  When the resin (A) has an acid stable structural unit (a2-1), the content ratio is preferably in the range of 3 to 45 mol%, and 5 to 40 mol% with respect to all the structural units of the resin (A). Is more preferable, and the range of 5 to 35 mol% is more preferable.

式（ａ２−０）中、
Ｒ^a30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^a31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のアシル基、炭素数２〜４のアシルオキシ基、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。
ｍａは０〜４の整数を表す。ｍａが２以上の整数である場合、複数のＲ^a31の全部又は一部は同じであってもよい。 Next, the acid stable structural unit which has a phenolic hydroxy group among the acid stable structural units which have a hydroxy group is demonstrated. The acid stable structural unit is preferably one represented by the following formula (a2-0) (hereinafter sometimes referred to as “acid stable structural unit (a2-0)”).

In formula (a2-0),
R ^a30 represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
R ^a31 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 acyl group having 2 to 4 carbon atoms, an acyloxy group having 2 to 4 carbon atoms, an acryloyloxy group, or Represents a methacryloyloxy group.
ma represents an integer of 0 to 4. When ma is an integer of 2 or more, all or some of the plurality of R ^a31 may be the same.

Specific examples of the “alkyl group having 1 to 6 carbon atoms” in the “alkyl group having 1 to 6 carbon atoms which may have a halogen atom” for R ^a30 include those already exemplified in this range. . The “C 1-6 alkyl group having a halogen atom” is one in which at least a part of the hydrogen atoms contained in the C 1-6 alkyl group is substituted with a halogen atom. The specific example of the halogen atom is as already described. Among these, R ^a30 is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group and an ethyl group, and further preferably a methyl group.
Specific examples of the alkoxy group of R ^a31 include those already exemplified in the range of 1 to 6 carbon atoms. Among these, R ^a31 is preferably an alkoxy group having 1 to 4 carbon atoms, more preferably a methoxy group and an ethoxy group, and further preferably a methoxy group.
ma is preferably 0, 1 or 2, more preferably 0 or 1, and still more preferably 0.
ma is preferably 0, 1 or 2, more preferably 0 or 1, and still more preferably 0.

Among the acid stable structural units (a2-0), in the following formula (a2-0-1), formula (a2-0-2), formula (a2-0-3) and formula (a2-0-4) Those represented respectively are preferred. An acid stable monomer capable of deriving such a structural unit is described in, for example, JP 2010-204634 A.

  Acid-stable monomer capable of deriving acid-stable structural unit (a2-0) such as p-hydroxystyrene and p-hydroxy-α-methylstyrene [hereinafter referred to as “acid-stable monomer (a2)” in some cases. ] In the production of the resin (A), the acid stable structural unit (a2-0) represented by the formula (a2-0-1) or the formula (a2-0-2) is converted into the resin (A). After the phenolic hydroxy group in the acid stable monomer (a2) is protected with a protecting group such as an acetyl group to form a protected acid stable monomer (a2), the protected acid Resin (A) can also be manufactured using a stable monomer (a2). A resin (A) having an acid-stable structural unit (a2-0) can be produced by deprotecting a resin having a structural unit derived from the protected acid-stable monomer (a2) and removing the protecting group. . However, when carrying out the deprotection treatment, it is necessary to carry out the deprotection treatment without significantly damaging the other structural unit (a1).

  When the resin (A) has an acid stable structural unit (a2-0), the content ratio is preferably in the range of 5 to 90 mol% with respect to the total structural unit (100 mol%) of the resin (A). The range of 10-85 mol% is more preferable, and the range of 15-80 mol% is further more preferable.

<Acid stable structural unit (a3)>
The lactone ring possessed by the acid stable structural unit (a3) may be monocyclic such as β-propiolactone ring, γ-butyrolactone ring and δ-valerolactone ring, monocyclic lactone ring and other rings. Or a condensed ring. Among these lactone rings, a γ-butyrolactone ring and a condensed ring of a γ-butyrolactone ring and another ring are preferable.

［式（ａ３−１）中、
Ｌ^a4は、酸素原子又は＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a18は、水素原子又はメチル基を表す。
ｐ１は０〜５の整数を表す。
Ｒ^a21は炭素数１〜４の脂肪族炭化水素基を表し、ｐ１が２以上の場合、複数のＲ^a21の全部又は一部は同じであってもよい。
式（ａ３−２）中、
Ｌ^a5は、酸素原子又は＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
ｑ１は、０〜３の整数を表す。
Ｒ^a22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し、ｑ１が２以上の場合、複数のＲ^a22の全部又は一部は同じであってもよい。
式（ａ３−３）中、
Ｌ^a6は、酸素原子又は＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a20は、水素原子又はメチル基を表す。
ｒ１は、０〜３の整数を表す。
Ｒ^a23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し、ｒ１が２以上の場合、複数のＲ^a23の全部又は一部は同じであってもよい。］ The acid stable structural unit (a3) is preferably one represented by the following formula (a3-1), formula (a3-2) or formula (a3-3). Resin (A) may have only 1 type among these, and may have 2 or more types. In the following description, what is represented by formula (a3-1) may be referred to as “acid-stable structural unit (a3-1)”, and what is represented by formula (a3-2) is “acid In some cases, it is referred to as “stable structural unit (a3-2)”, and what is represented by the formula (a3-3) may be referred to as “acid stable structural unit (a3-3)”.

[In the formula (a3-1),
L ^a4 represents an oxygen atom or a group represented by * —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a18 represents a hydrogen atom or a methyl group.
p1 represents an integer of 0 to 5.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and when p1 is 2 or more, all or some of the plurality of R ^a21 may be the same.
In formula (a3-2),
L ^a5 represents an oxygen atom or a group represented by * —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
q1 represents an integer of 0 to 3.
R ^a22 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and when q1 is 2 or more, all or some of the plurality of R ^a22 may be the same.
In formula (a3-3),
L ^a6 represents an oxygen atom or a group represented by * —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a20 represents a hydrogen atom or a methyl group.
r1 represents an integer of 0 to 3.
R ^a23 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms. When r1 is 2 or more, all or some of the plurality of R ^a23 may be the same. ]

In formula (a3-1) to formula (a3-3), L ^{a4 to} L ^a6 are the same as those described for L ^a3 in formula (a2-1).
L ^{a4 to} L ^a6 are each independently an oxygen atom or a group represented by * —O— (CH ₂ ) _k3 —CO—O— in which k3 is an integer of 1 to 4, preferably an oxygen atom and * —O—CH ₂ —CO—O— is more preferable, and an oxygen atom is more preferable.
R ^{a18 to} R ^a21 are preferably methyl groups.
R ^a22 and R ^a23 are each independently preferably a carboxy group, a cyano group or a methyl group.
p1, q1 and r1 are preferably integers of 0 to 2, more preferably 0 or 1. When p1 is 2, two R ^a21 may be the same as or different from each other. When q1 is 2, two R ^a22 may be the same as or different from each other, and r1 is 2. Two R ^a23 may be the same or different from each other.

  Hereinafter, preferred examples of the acid stable structural unit (a3-1), the acid stable structural unit (a3-2), and the acid stable structural unit (a3-3) will be shown.

Preferable examples of the acid stable structural unit (a3-1) include the following formula (a3-1-1), formula (a3-1-2), formula (a3-1-3) and formula (a3-1-4). ) Respectively.

Preferable examples of the acid stable structural unit (a3-2) include the following formula (a3-2-1), formula (a3-2-2), formula (a3-2-3) and formula (a3-2-4). ) Respectively.

Preferred examples of the acid stable structural unit (a3-3) include the following formula (a3-3-1), formula (a3-3-2), formula (a3-3-3) and formula (a3-3-4). ) Respectively.

  The acid stable structural unit (a3-1), the acid stable structural unit (a3-2), and the acid stable structural unit (a3-3) can be derived from an acid stable monomer described in JP 2010-204646 A. Among the specific examples of the acid stable structural unit (a3), the formula (a3-1-1), the formula (a3-1-2), the formula (a3-2-3), and the formula (a3-2-4) Is more preferable, and the acid stable structural unit represented by Formula (a3-1-1) or Formula (a3-2-3) is more preferable.

When the resin (A) has an acid stable structural unit (a3), the total content is preferably in the range of 5 to 70 mol% with respect to all the structural units (100 mol%) of the resin (A). The range of 10 to 65 mol% is more preferable, and the range of 10 to 60 mol% is more preferable.
The content of each of the structural unit derived from the monomer (a3-1), the structural unit derived from the monomer (a3-2), and the structural unit derived from the monomer (a3-3) is the total structure of the resin (A). 5-60 mol% is preferable with respect to a unit (100 mol%), the range of 5-50 mol% is more preferable, and the range of 10-50 mol% is more preferable.

<Other acid stable structural units>
The preferred acid stable structural unit (a2) and acid stable structural unit (a3) have been described as the acid stable structural unit possessed by the resin (A). However, the resin (A) contains the acid stable structural unit (a2) and the acid stable structural unit. It may have an acid stable structural unit other than the structural unit (a3). Here, the acid stable structural unit (a4) other than the acid stable structural unit (a2) and the acid stable structural unit (a3) is referred to. Hereinafter, the acid-stable structural unit (a4) will be described by showing an acid-stable monomer (hereinafter sometimes referred to as “acid-stable monomer (a4)”) from which the acid-stable structural unit (a4) can be derived.

［式（ａ４−１）中、
Ｒ^４１は、水素原子又はメチル基を表す。
Ａ^４０は、式（ａ４−ｇ１）で表される基を表す。

（式（ａ４−ｇ１）中、
ｓｓは０〜２の整数を表す。
Ａ^４１及びＡ^４２は、それぞれ独立に、炭素数１〜５の脂肪族炭化水素基を表す。
ｓｓが２のとき、複数存在するＡ^４１は、互いに同一であるか相異なる。
Ｘ^４０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。
ｓｓが２のとき、複数存在するＸ^４０は、互いに同一であるか相異なる。）
Ｒ^４２は、フッ素原子を有する炭素数１〜１８の脂肪族炭化水素基を表し、該脂肪族炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。］
Ａ^４２の脂肪族炭化水素基は、典型的にはアルカンジイル基であり、当該アルカンジイル基は直鎖状であっても、分岐していてもよい。当該アルカンジイル基は炭素数１〜５の範囲ですでに例示したものを含むが、中でも、Ａ^４１としては、炭素数１〜４のアルカンジイル基がより好ましく、エチレン基がさらに好ましい。 A specific example of the acid stable monomer (a4) is, for example, a monomer represented by the following formula (a4-1) (hereinafter sometimes referred to as “monomer (a4-1)”).

[In the formula (a4-1),
R ⁴¹ represents a hydrogen atom or a methyl group.
A ⁴⁰ represents a group represented by the formula (a4-g1).

(In the formula (a4-g1),
ss represents an integer of 0-2.
A ⁴¹ and A ⁴² each independently represents an aliphatic hydrocarbon group having 1 to 5 carbon atoms.
When ss is 2, a plurality of A ⁴¹ are the same or different from each other.
X ⁴⁰ represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
When ss is 2, a plurality of X ⁴⁰ are the same or different from each other. )
R ⁴² represents a C 1-18 aliphatic hydrocarbon group having a fluorine atom, and the methylene group constituting the aliphatic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group. ]
The aliphatic hydrocarbon group for A ⁴² is typically an alkanediyl group, and the alkanediyl group may be linear or branched. The alkanediyl group includes those already exemplified in the range of 1 to 5 carbon atoms. Among them, as A ⁴¹ , an alkanediyl group having 1 to 4 carbon atoms is more preferable, and an ethylene group is more preferable.

  Specific examples of the group represented by the formula (a4-g1) (hereinafter sometimes referred to as “group (a4-g1)”) are shown below. In each specific example, * represents a bond. In addition, when the said group (a4-g1) has both an oxygen atom and a carbonyl group, it is preferable to have in the form of a carbonyloxy group or an oxycarbonyl group.

などが挙げられる。 As the group having an oxygen atom (a4-g1),

Etc.

などが挙げられる。 As the group having a carbonyl group (a4-g1),

Etc.

などが挙げられる。 As the group having a carbonyloxy group (a4-g1),

Etc.

などが挙げられる。 As the group having an oxycarbonyl group (a4-g1),

Etc.

^R42 is a group in which at least one of the hydrogen atoms contained in the aliphatic hydrocarbon group is replaced with a fluorine atom. The aliphatic hydrocarbon group may partially have a carbon-carbon unsaturated bond, but an aliphatic saturated hydrocarbon group having no carbon-carbon unsaturated bond is preferable. Examples of the aliphatic saturated hydrocarbon group include alkyl groups (straight and branched) and alicyclic hydrocarbon groups, and aliphatic hydrocarbon groups obtained by combining alkyl groups and alicyclic hydrocarbon groups.

Specific examples of the aliphatic hydrocarbon group having a fluorine atom represented by R ⁴² include a difluoromethyl group, a trifluoromethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, 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 , 1,2,2,3,3,4,4-octafluorobutyl group, perfluorobutyl group, 1,1-bis (trifluoro) methyl-2,2,2-trifluoroethyl group, 2- (Perfluoropropyl) ethyl group, 1,1,2,2,3,3,4,4-octafluoropentyl group, perfluoropentyl group, 1,1,2,2,3,3,4,4,5 5-decafluoropentyl group, 1,1-bis (trifluoromethyl) -2,2,3,3,3-pentafluoropropyl group, perfluoropentyl group, perfluorocyclopentyl group, 2- (perfluorobutyl) ethyl group, 1,1,2,2,3,3,4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,4,5,5,6,6-dodeca Examples thereof include a fluorohexyl group, a perfluorocyclohexyl group, a perfluoropentylmethyl group, and a perfluorohexyl group.

（式（ａ−ｇ２）中、
Ａ^５１は、フッ素原子を有していてもよい炭素数１〜１５の２価の脂肪族炭化水素基を表す。
Ｘ^５０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^５０は、フッ素原子を有していてもよい炭素数１〜１５の１価の脂肪族炭化水素基を表す。
但し、Ａ^５０又はＡ^５1の少なくともいずれかはフッ素原子を有するものであり、Ａ^５０及びＡ^５1の炭素数の合計は１７以下である。） Examples of the group in which the methylene group constituting the aliphatic hydrocarbon group of R ⁴² is replaced by an oxygen atom or a carbonyl group include a group represented by the formula (a-g2) (hereinafter, “group (a-g2 ) ”)).

(In the formula (a-g2),
A ⁵¹ represents a C 1-15 divalent aliphatic hydrocarbon group which may have a fluorine atom.
X ⁵⁰ represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ⁵⁰ represents a monovalent aliphatic hydrocarbon group having carbon atoms of 1 to 15 which may have a fluorine atom.
Provided ^that at least one of ^{A 50} or ^{A 51} are those having a fluorine ^atom, the total number of carbon atoms of ^{A 50} and ^{A 51} is 17 or less. )

When A ⁵¹ is a divalent aliphatic hydrocarbon group having a fluorine atom, the aliphatic hydrocarbon group is typically an alkanediyl group having a fluorine atom and a divalent alicyclic carbon group having a fluorine atom. Examples thereof include a hydrogen group (preferably a cycloalkanediyl group having a fluorine atom). The alkanediyl group having a fluorine atom is one in which part or all of the hydrogen atoms contained in the alkanediyl group are substituted with a fluorine atom, and the divalent alicyclic hydrocarbon group having a fluorine atom is 2 Some or all of the hydrogen atoms contained in the valent alicyclic hydrocarbon group are substituted with fluorine atoms.

Here, when the monomer (a4-1) is shown as a specific example in the case where R ⁴² is an aliphatic hydrocarbon group having a fluorine atom and A ⁴⁰ is an ethylene group, the following formula (a4-1-1) To monomers represented by formula (a4-1-22).

The aliphatic hydrocarbon group having a fluorine atom of R ⁴² is a perfluoroalkyl group in which all of the hydrogen atoms contained in the alkyl group are substituted with fluorine atoms (for example, a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group). Group, perfluoropentyl group, perfluorohexyl group, perfluoroheptyl group and perfluorooctyl group) or a perfluorocycloalkyl group in which all hydrogen atoms contained in the cycloalkyl group are substituted with fluorine atoms.

The compound in which R ⁴² is a perfluoroalkyl group or a perfluorocycloalkyl group includes the above-described formula (a4-1-3), formula (a4-1-4), formula (a4-1-7), and formula (a4- 1-8), formula (a4-1-11), formula (a4-1-12), formula (a4-1-15), formula (a4-1-16), formula (a4-1-19), The compounds represented by formula (a4-1-20), formula (a4-1-21), and formula (a4-1-22) correspond to this.

R ⁴² is more preferably a perfluoroalkyl group. More preferably, it is a C1-C6 perfluoroalkyl group, More preferably, it is a C1-C3 perfluoroalkyl group.

［式（ａ４−１’）中、すべての符号はいずれも、前記と同義である。］ The monomer (a4-1) in which R ⁴² is a group represented by the formula (a-g2) is represented by the following formula (a4-1 ′) (hereinafter, “monomer (a4-1 ′” ) ").

[In the formula (a4-1 ′), all symbols are as defined above. ]

In the monomer (a4-1 ′), both A ⁵⁰ and A ⁵¹ may have a fluorine atom, but preferably one of them is an aliphatic hydrocarbon group having a fluorine atom. Further, it is preferable that A ⁵⁰ is an aliphatic hydrocarbon group having a fluorine atom, among them, A ⁵⁰ is more preferable alkanediyl group having a fluorine atom, and more preferred is a perfluoro alkanediyl group .

R ⁴² is perfluorinated alkanediyl ^group, the monomer ^{A 40} is an ethylene group (a4-1 '), respectively by the following formulas (a4-1'-1) ~ formula (a4-1'-46) And monomers represented.

The number of carbon atoms of A ⁵⁰ and ^{A 51} is their sum is arbitrarily selected in the range of 17 or ^less, the number of carbon atoms of ^{A 51} is preferably 1-6, 1-3 is more preferable. On the other ^hand, the number of carbon atoms of ^{A 50} is preferably 4 to 15, 5 to 12 is more preferable. Further preferred A ⁵⁰ is an alicyclic hydrocarbon group having 6 to 12 carbon atoms, and a cyclohexyl group and an adamantyl group are even more preferred.

The group (a-g2) is as follows when A ⁵¹ is an aliphatic hydrocarbon group having a fluorine atom and A ⁵⁰ is a cyclohexyl group or an adamantyl group.

このような基（ａ−ｇ２）を有するモノマー（ａ４−１’）は、上述した具体例の中では、式（ａ４−１’−７）〜式（ａ４−１’−４２）でそれぞれ表されるものが該当する。

Among the specific examples described above, the monomer (a4-1 ′) having such a group (a-g2) is represented by formula (a4-1′-7) to formula (a4-1′-42), respectively. Applicable.

  When the resin (A) has a structural unit derived from the monomer (a4-1), the content thereof ranges from 1 to 20 mol% with respect to all the structural units (100 mol%) of the resin (A). Preferably, the range of 2-15 mol% is more preferable, and the range of 3-10 mol% is more preferable.

<Method for producing resin (A)>
The resin (A) is obtained by copolymerizing the monomer (a1) for deriving the structural unit (a1), more preferably the monomer (a1) and an acid stable monomer, and more preferably the structural unit. (A1-1) and / or monomer (a1) for deriving structural unit (a1-2) and acid-stable monomer for deriving acid-stable structural unit (a2) and / or acid-stable structural unit (a3) Polymerized. Moreover, a monomer (a4-1) can also be used as an acid stable monomer as needed. When the resist composition is used for, for example, EUV exposure, the monomer (a1) for deriving the structural unit (a1-1) and / or the structural unit (a1-2), and the acid stable structural unit (a2- And an acid-stable monomer derived from 0).
The resin (A) further preferably has a structural unit (a1-1) having an adamantyl group as the structural unit (a1). The resin (A) can be produced by subjecting the monomer as described above to a known polymerization method (for example, radical polymerization method) and polymerizing (copolymerizing) it.
On the other hand, the resin (X) is preferably obtained by polymerizing the monomer (a4-1) [monomer (a4-1 ′)] by a known polymerization method, and this polymerization [production of resin (X)] In addition to monomer (a4-1) [monomer (a4-1 ′)], other acid-stable monomers [for example, monomers that induce acid-stable structural units (a2) or acid-stable structural units (a3)] These may be copolymerized using these.

The weight average molecular weight of the resin (A) is preferably 2,500 or more (more preferably 3,000 or more) and 50,000 or less (more preferably 30,000 or less). In addition, the weight average molecular weight here is calculated | required as a conversion value of a standard polystyrene reference | standard by gel permeation chromatography analysis. Detailed analysis conditions for this analysis are described in the Examples of the present application.
On the other hand, when the resin (X) is used in the resist composition, the weight average molecular weight of the resin (X) is preferably 8,000 or more (more preferably 10,000 or more), 80,000 or less (more preferably). Is less than 60,000). The means for measuring the weight average molecular weight of the resin (X) is the same as that for the resin (A).

<This resist composition>
As described above, the resist composition contains the salt (I) and the resin (A).
Moreover, it is preferable that this resist composition contains a basic compound (C) and a solvent (D) further.

<Basic compound (C)>
The resist composition preferably contains a basic compound (C). Such a basic compound (C) is called a quencher in the technical field in question. The basic compound (C) is preferably a basic nitrogen-containing organic compound, and examples thereof include amines and ammonium salts. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines. The basic compound (C) is preferably a compound represented by the formula (C1) to a compound represented by the formula (C8), more preferably a compound represented by the formula (C1-1). It is done.

［式（Ｃ１）中、
Ｒ^c1、Ｒ^c2及びＲ^c3は、それぞれ独立に、水素原子、炭素数１〜６のアルキル基、炭素数５〜１０の脂環式炭化水素基又は炭素数６〜１０の芳香族炭化水素基を表し、該アルキル基及び該脂環式炭化水素基に含まれる水素原子は、ヒドロキシ基、アミノ基又は炭素数１〜６のアルコキシ基で置換されていてもよく、該芳香族炭化水素基に含まれる水素原子は、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５〜１０の脂環式炭化水素又は炭素数６〜１０の芳香族炭化水素基で置換されていてもよい。］

[In the formula (C1),
R ^c1 , R ^c2 and R ^c3 are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 5 to 10 carbon atoms or an aromatic hydrocarbon group having 6 to 10 carbon atoms. The hydrogen atom contained in the alkyl group and the alicyclic hydrocarbon group may be substituted with a hydroxy group, an amino group, or an alkoxy group having 1 to 6 carbon atoms, and the aromatic hydrocarbon group The hydrogen atom contained is substituted with an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alicyclic hydrocarbon having 5 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms. It may be. ]

［式（Ｃ１−１）中、
Ｒ^c2及びＲ^c3は、前記と同義である。
Ｒ^c4は、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５〜１０の脂環式炭化水素又は炭素数６〜１０の芳香族炭化水素基を表す。
ｍ３は０〜３の整数を表し、ｍ３が２以上のとき、複数のＲ^c4の全部又は一部は同じであってもよい。］

[In the formula (C1-1),
R ^c2 and R ^c3 are as defined above.
R ^c4 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alicyclic hydrocarbon having 5 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms.
m3 represents an integer of 0 to 3, and when m3 is 2 or more, all or some of the plurality of R ^c4 may be the same. ]

［式（Ｃ２）、式（Ｃ３）及び式（Ｃ４）中、
Ｒ^c5、Ｒ^c6、Ｒ^c7及びＲ^c8は、それぞれ独立に、Ｒ^c1と同義である。
Ｒ^c9は、炭素数１〜６のアルキル基、炭素数３〜６の脂環式炭化水素基又は炭素数２〜６のアルカノイル基を表す。
ｎ３は０〜８の整数を表し、ｎ３が２以上のとき、複数のＲ^c9の全部又は一部は同じであってもよい。］

[In Formula (C2), Formula (C3) and Formula (C4),
R ^c5 , R ^c6 , R ^c7 and R ^c8 are each independently synonymous with R ^c1 .
R ^c9 represents an alkyl group having 1 to 6 carbon atoms, an alicyclic hydrocarbon group having 3 to 6 carbon atoms, or an alkanoyl group having 2 to 6 carbon atoms.
n3 represents an integer of 0 to 8, and when n3 is 2 or more, all or some of the plurality of R ^c9 may be the same. ]

［式（Ｃ５）及び式（Ｃ６）中、
Ｒ^c10、Ｒ^c11、Ｒ^c12、Ｒ^c13及びＲ^c16は、それぞれ独立に、Ｒ^c1と同義である。
Ｒ^c14、Ｒ^c15及びＲ^c17は、それぞれ独立に、Ｒ^c4と同義である。
ｏ３及びｐ３は、それぞれ独立に０〜３の整数を表し、ｏ３が２以上であるとき、複数のＲ^c14の全部又は一部は同じであってもよい。ｐ３が２以上であるとき、複数のＲ^c15の全部又は一部は同じであってもよい。
Ｌ^c1は、炭素数１〜６のアルカンジイル基、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｓ−又はこれらを組合せた２価の基を表す。］

[In Formula (C5) and Formula (C6),
R ^c10 , R ^c11 , R ^c12 , R ^c13 and R ^c16 are each independently synonymous with R ^c1 .
R ^c14 , R ^c15 and R ^c17 each independently have the same ^meaning as R ^c4 .
o3 and p3 each independently represent an integer of 0 to 3. When o3 is 2 or more, all or some of the plurality of R ^c14 may be the same. When p3 is 2 or more, all or some of the plurality of R ^c15 may be the same.
L ^c1 represents an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

［式（Ｃ７）及び式（Ｃ８）中、
Ｒ^c18、Ｒ^c19及びＲ^c20は、それぞれ独立に、Ｒ^c4と同義である。
ｑ３、ｒ３及びｓ３は、それぞれ独立に０〜３の整数を表し、ｑ３が２以上であるとき、複数のＲ^c18の全部又は一部は同じであってもよい。ｒ３が２以上であるとき、複数のＲ^c19の全部又は一部は同じであってもよい。ｓ３が２以上であるとき、複数のＲ^c20の全部又は一部は同じであってもよい。
Ｌ^c2は、単結合又は炭素数１〜６のアルカンジイル基、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｓ−又はこれらを組合せた２価の基を表す。］

[In Formula (C7) and Formula (C8),
R ^c18, R ^c19 and R ^c20 in each occurrence independently has the same meaning as R ^c4.
q3, r3 and s3 each independently represents an integer of 0 to 3, and when q3 is 2 or more, all or some of the plurality of R ^c18 may be the same. When r3 is 2 or more, all or some of the plurality of R ^c19 may be the same. When s3 is 2 or more, all or some of the plurality of R ^c20 may be the same.
L ^c2 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

  Examples of the compound represented by the formula (C1) 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, tri Pentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyl Hexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonyl Amine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2- Examples thereof include diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, and 4,4′-diamino-3,3′-diethyldiphenylmethane. Propyl aniline. Particularly preferred include 2,6-diisopropylaniline.

Examples of the compound represented by the formula (C2) include piperazine.
Examples of the compound represented by the formula (C3) include morpholine.
Examples of the compound represented by the formula (C4) include piperidine and hindered amine compounds having a piperidine skeleton described in JP-A No. 11-52575.
Examples of the compound represented by the formula (C5) include 2,2′-methylenebisaniline.
Examples of the compound represented by the formula (C6) include imidazole and 4-methylimidazole.
Examples of the compound represented by the formula (C7) include pyridine and 4-methylpyridine.
Examples of the compound represented by the formula (C8) include 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 1,2-di (2-pyridyl) ethene, 1, 2-di (4-pyridyl) ethene, 1,3-di (4-pyridyl) propane, 1,2-di (4-pyridyloxy) ethane, di (2-pyridyl) ketone, 4,4′-dipyridyl sulfide 4,4′-dipyridyl disulfide, 2,2′-dipyridylamine, 2,2′-dipiconylamine, bipyridine and the like.

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

<Solvent (D)>
When the present resist composition contains a solvent (D), the solvent (D) depends on the type and amount of the salt (I), the resin (A), etc. In addition, an optimum one can be appropriately selected from the viewpoint that the coating property when the resist composition is applied is improved.

  Examples of the solvent (D) 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 Examples thereof include esters such as ethyl pyruvate; ketones such as acetone, methyl isobutyl ketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone. A solvent (D) may be used individually by 1 type, and may use 2 or more types together.

<Other ingredients>
The resist composition comprises a salt (I) and a resin (A), preferably an acid generator containing the salt (I), a resin (A), and a basic compound (C) and a solvent (D used as necessary). ), But may contain components other than the basic compound (C) and the solvent (D) used as necessary. This component may be referred to as “component (F)”. Examples of the component (F) include additives known in the art, for example, polymer compounds other than the resin (A), sensitizers, dissolution inhibitors, surfactants, stabilizers, and dyes.

<Preparation method of the present resist composition>
Then, the preparation method of this resist composition is demonstrated.
A suitable present resist composition can be usually prepared by mixing the salt (I) and the resin (A) in the presence of the solvent (D). Furthermore, you may mix an acid generator (B), a basic compound (C), and / or a component (F) as needed as above-mentioned. It is preferable to mix the basic compound (C). The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can select the suitable temperature range from the range of 10-40 degreeC according to the solubility with respect to solvent (D), such as a kind (resin (A)), such as resin (A). An appropriate 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 can be used.
By selecting the amount of each component used when preparing the resist composition of the present invention, the content of each component in the resist composition of the present invention can be adjusted.

  The content ratio of the acid generator in the resist composition is preferably 40% by mass or less, more preferably 35% by mass or less, and preferably 1% by mass or more, more preferably based on the solid content of the resist composition. Is 3% by mass or more. In addition, solid content here means the sum total of what remove | excluded the solvent (D) from this resist composition. The solid content can be determined by subjecting the resist composition to analysis such as liquid chromatography and gas chromatography. When the acid generator contained in the resist composition is substantially only the salt (I), the “content ratio of the acid generator” described here should be read as “content ratio of the salt (I)”. Can do.

  On the other hand, as described above, in addition to the salt (I), other acid generators other than the salt (I) (preferably an ionic acid generator, particularly preferably the acid generator ( In the case of B)), the above-mentioned “content ratio of acid generator” can be read as “total content ratio of salt (I) and other acid generators”. In this case, the salt (I) is preferably 10 parts by mass or more and particularly preferably 30 parts by mass or more with respect to 100 parts by mass of the total amount of the acid generator. In the resist composition, when the salt (I) and another ionic acid generator are used in combination in the resist composition, only the other ionic acid generator is used as the acid generator. It has been found that the focus margin tends to be further improved as compared to the resist composition. The reason for this effect is not clear, but is based on the inventors' original knowledge.

  A preferable range of the content ratio of the resin (A) in the resist composition is determined based on the solid content of the resist composition. Specifically, the resin (A) is preferably 80% by mass or more based on the mass of the solid content. The resist composition is a resin other than the resin (A), that is, a resin not having the above-mentioned acid action characteristics (hereinafter sometimes referred to as “resin (X)”) as long as the effects of the present invention are not significantly impaired. Can also be included. The resin (X) preferably has a fluorine atom in its molecule, and more preferably has a structural unit derived from an acid-stable monomer having a fluorine atom. More specifically, when this resin (X) is exemplified, a resin (X) having a structural unit derived from the monomer (a4-1) can be exemplified. In the resin (X) in this case, the content ratio of the structural unit derived from the monomer (a4-1) is preferably in the range of 70 to 100 mol% with respect to all the structural units of the resin (X), and 80 to 100 The range of mol% is more preferable, and the range of 90 to 100 mol% is more preferable.

  In the present resist composition, when the resin (X) is contained in addition to the resin (A), the content ratio of the resin (X) is 0.1 to 10% by mass based on the solid content of the resist composition. Is preferable, 0.3-5 mass% is more preferable, 0.5-3 mass% is further more preferable.

  When the basic compound (C) is contained in the resist composition, the content ratio is preferably about 0.01 to 5% by mass with respect to the solid content of the resist composition, more preferably 0.8. It is about 01 to 3% by mass, particularly preferably about 0.01 to 1% by mass.

  The content ratio of the solvent (D) in the present resist composition is 90% by mass or more, preferably 92% by mass or more, more preferably 94% by mass or more, based on the total mass of the present resist composition. 0.9 mass% or less, preferably 99 mass% or less.

  When the resist composition contains the component (F), the appropriate content can be adjusted according to the type of the component (F).

  Thus, each of acid generator and resin (A) containing salt (I), and resin (X), basic compound (C), solvent (D) or component (F) used as necessary After mixing with a preferable content, it is preferable to filter using a filter having a pore size of about 0.003 to 0.2 μm.

<Method for producing resist pattern>
Specifically showing a method for producing a resist pattern using the present resist composition,
(1) a step of applying the resist composition on a substrate;
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer,
Examples of the method include (4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating. Hereinafter, each of the steps shown here is referred to as “step (1)” to “step (5)”.

  Application of the resist composition on the substrate in the step (1) can be performed by a coating apparatus widely used for applying a resist material for semiconductor microfabrication, such as a spin coater. Thus, a coating film made of a resist composition is formed on the substrate. The film thickness of the coating film can be adjusted by variously adjusting the conditions (coating conditions) of the coating apparatus, and by applying an appropriate preliminary experiment, the coating film can be applied to have a desired film thickness. You can choose the conditions. Various substrates to be subjected to microfabrication can be selected as the substrate before applying the resist composition. The substrate may be washed or an antireflection film may be formed before applying the resist composition. For example, a commercially available composition for an organic antireflection film can be used for forming the antireflection film.

In the step (2), the present resist composition coated on the substrate, that is, the coated film is dried to remove the solvent (D). Drying is performed, for example, by evaporating the solvent from the coating film by heating means using a heating device such as a hot plate (so-called pre-baking), decompressing means using a decompressing device, or by combining these means. Is called. The drying conditions can be selected according to the type of the solvent (D) contained in the resist composition. For example, in the case of a heating means using a hot plate, the surface temperature of the hot plate is set in the range of about 50 to 200 ° C. Preferably it is done. In the decompression means, it is preferable to enclose the substrate on which the coating film is formed in an appropriate decompressor, and then set the internal pressure of the decompressor to about 1 to 1.0 × 10 ⁵ Pa. Thus, the composition layer is formed on the substrate by removing the solvent from the coating film.

Step (3) is a step of exposing the composition layer, and preferably a step of exposing the composition layer using an exposure machine. The exposure is performed through a mask (photomask) on which a desired pattern to be finely processed is formed. As an exposure light source of the exposure machine, an ultraviolet light source such as a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), an F ₂ excimer laser (wavelength 157 nm), or a solid-state laser light source (YAG In addition, various lasers such as a laser beam from a laser beam from a semiconductor laser or the like to emit a harmonic laser beam in the far ultraviolet region or the vacuum ultraviolet region can be used. The exposure machine may be an immersion exposure machine. The exposure machine may irradiate an electron beam or extreme ultraviolet light (EUV). In this specification, irradiating these radiations may be collectively referred to as “exposure”.
By exposing through a mask, the composition layer has an exposed portion (exposed portion) and an unexposed portion (unexposed portion). In the composition layer of the exposed portion, the acid generator (including salt (I)) contained in the composition layer receives exposure energy to generate an acid, and further, by the action with the generated acid, the “alkaline aqueous solution” Since the acid labile group in the resin (A) of the “resin that is insoluble or hardly soluble and becomes soluble in an alkaline aqueous solution by the action of an acid” generates a hydrophilic group by a deprotection reaction, the composition layer of the exposed portion The resin (A) in (1) is soluble in an alkaline aqueous solution. On the other hand, since the exposure energy is not received in the unexposed area, the resin (A) remains insoluble or hardly soluble in the alkaline aqueous solution. Since the composition layer in the exposed portion and the composition layer in the unexposed portion are significantly different in solubility in an alkaline aqueous solution, a resist pattern can be formed by development with the alkaline aqueous solution.

  In step (4), the composition layer after exposure is subjected to heat treatment (so-called post-exposure baking). Such heat treatment is preferably the heating means using the hot plate shown in the step (2). In addition, when performing the heating means using a hot plate in the step (4), the surface temperature of the hot plate is preferably about 50 to 200 ° C, more preferably about 70 to 150 ° C. The deprotection reaction is promoted by the heat treatment.

Step (5) is a step of developing the heated composition layer, and preferably the heated composition layer is developed with a developing device. In the step of developing, when the composition layer after heating is brought into contact with an alkaline aqueous solution, the exposed composition layer is dissolved and removed in the alkaline aqueous solution, and the unexposed composition layer remains on the substrate. A resist pattern is manufactured on the substrate.
As the alkaline aqueous solution, those known in this technical field called “alkaline developer” can be used. Examples of the alkaline aqueous solution include an aqueous solution of tetramethylammonium hydroxide and an aqueous solution of (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline).

  After the development, it is preferable to perform a rinsing treatment with ultrapure water or the like. Furthermore, it is preferable to remove moisture remaining on the substrate and the resist pattern.

  According to the resist pattern manufacturing method including the steps (1) to (5) as described above, this resist composition can manufacture a resist pattern with an excellent focus margin.

<Application>
This resist composition 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) irradiation, or a resist composition for EUV exposure.

Hereinafter, the present invention will be described in detail by way of examples.
In Examples and Comparative Examples, “%” and “part” representing the content and the amount used are based on mass unless otherwise specified.
The weight average molecular weight is a value determined by gel permeation chromatography (HLC-8120GPC type manufactured by Tosoh Corporation, three columns are “TSKgel Multipore HXL-M”, and the solvent is tetrahydrofuran) using polystyrene as a standard product.
Column: TSKgel Multipore H _XL -M x 3 + guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)

  The structure of the compound was confirmed by measuring the molecular peak using mass spectrometry (LC is model 1100 manufactured by Agilent, and MASS is LC / MSD manufactured by Agilent). In the following examples, the value of this molecular peak is indicated by “MASS”.

式（Ｉ−２−ａ）で表される塩２．９８部、式（Ｉ−２−ｂ）で表される化合物０．５８部及びモノクロロベンゼン２４．００部を反応器に仕込み、２３℃で３０分間攪拌した。その後、式（Ｉ−２−ｃ）で表される安息香酸銅０．０４部を添加し、１００℃程度まで昇温した後、同温度で１時間攪拌した。得られた反応物を濃縮した後、得られた濃縮物に、クロロホルム４０部及びイオン交換水１０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水１０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。この水洗操作をさらに５回繰り返した。回収された有機層をろ過した後、得られたろ液を濃縮した。得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル２０部を加えて攪拌した。得られた上澄液を除去し、上澄液除去後の残渣をさらに濃縮した。得られた濃縮物をアセトニトリルに溶解した後、濃縮することにより、式（Ｉ−２−ｄ）で表される塩１．０１部を得た。

式（Ｉ−２−ｄ）で表される塩０．５４部、式（Ｉ−２−ｅ）で表される化合物０．２６部及びアセトニトリル１５．００部を仕込み、２３℃で３０分間攪拌した。得られた混合物に、トリエチルアミン０．１２部を仕込み、７５℃で３時間攪拌した。得られた混合物を、２３℃まで冷却し、クロロホルム３０部及びイオン交換水２０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。この水洗操作をさらに５回繰り返した。回収された有機層に活性炭０．５０部を加えて攪拌し、ろ過した。得られたろ液を濃縮し、酢酸エチル１０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル１０部を加えて攪拌した。得られた上澄液を除去し、上澄液除去後の残渣をさらに濃縮した。得られた濃縮物をアセトニトリルに溶解した後、濃縮することにより、式（Ｉ−２）で表される塩０．２６部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ４１９．２
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ３３９．１ Example 1 [Synthesis of a salt represented by the formula (I-2)]

A reactor was charged with 2.98 parts of a salt represented by the formula (I-2-a), 0.58 parts of a compound represented by the formula (I-2-b) and 24.00 parts of monochlorobenzene. For 30 minutes. Thereafter, 0.04 part of copper benzoate represented by the formula (I-2-c) was added, the temperature was raised to about 100 ° C., and the mixture was stirred at the same temperature for 1 hour. After concentrating the obtained reaction product, 40 parts of chloroform and 10 parts of ion-exchanged water were added to the obtained concentrate, followed by stirring at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 10 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This washing operation was further repeated 5 times. After the collected organic layer was filtered, the obtained filtrate was concentrated. 20 parts of tert-butyl methyl ether was added to the resulting concentrate and stirred. The resulting supernatant was removed, and the residue after removing the supernatant was further concentrated. The obtained concentrate was dissolved in acetonitrile and then concentrated to obtain 1.01 part of a salt represented by the formula (I-2-d).

0.54 parts of a salt represented by the formula (I-2-d), 0.26 parts of a compound represented by the formula (I-2-e) and 15.00 parts of acetonitrile were charged and stirred at 23 ° C. for 30 minutes. did. To the obtained mixture, 0.12 part of triethylamine was added and stirred at 75 ° C. for 3 hours. The obtained mixture was cooled to 23 ° C., 30 parts of chloroform and 20 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This washing operation was further repeated 5 times. To the collected organic layer, 0.50 parts of activated carbon was added, stirred and filtered. The obtained filtrate was concentrated, 10 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 10 parts of tert-butyl methyl ether was added and stirred. The resulting supernatant was removed, and the residue after removing the supernatant was further concentrated. The obtained concentrate was dissolved in acetonitrile and then concentrated to obtain 0.26 parts of the salt represented by the formula (I-2).
MASS (ESI (+) Spectrum): M ⁺ 419.2
MASS (ESI (−) Spectrum): M ^- 339.1

式（Ｉ−２−ｄ）で表される塩０．５４部、式（Ｉ−２−ｅ）で表される化合物０．５２部及びアセトニトリル１５．００部を反応器に仕込み、２３℃で３０分間攪拌した。得られた混合物に、トリエチルアミン０．２４部を仕込み、７５℃で５時間攪拌した。得られた混合物を、２３℃まで冷却し、クロロホルム３０部及びイオン交換水２０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。この水洗操作をさらに５回繰り返した。回収された有機層に活性炭０．５０部を加えて攪拌し、ろ過した。得られたろ液を濃縮し、酢酸エチル１０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル１０部を加えて攪拌した。得られた上澄液を除去し、上澄液除去後の残渣をさらに濃縮した。得られた濃縮物をアセトニトリルに溶解した後、濃縮することにより、式（Ｉ−１１４）で表される塩０．２９部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ６３９．４
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ３３９．１ Example 2 [Synthesis of salt represented by formula (I-114)]

A reactor was charged with 0.54 part of a salt represented by the formula (I-2-d), 0.52 part of a compound represented by the formula (I-2-e) and 15.00 parts of acetonitrile at 23 ° C. Stir for 30 minutes. The obtained mixture was charged with 0.24 part of triethylamine and stirred at 75 ° C. for 5 hours. The obtained mixture was cooled to 23 ° C., 30 parts of chloroform and 20 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This washing operation was further repeated 5 times. To the collected organic layer, 0.50 parts of activated carbon was added, stirred and filtered. The obtained filtrate was concentrated, 10 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 10 parts of tert-butyl methyl ether was added and stirred. The resulting supernatant was removed, and the residue after removing the supernatant was further concentrated. The obtained concentrate was dissolved in acetonitrile and then concentrated to obtain 0.29 parts of the salt represented by the formula (I-114).
MASS (ESI (+) Spectrum): M ⁺ 639.4
MASS (ESI (−) Spectrum): M ^- 339.1

式（Ｉ−２−ａ）で表される塩２．９８部、式（Ｉ−２３３−ｂ）で表される化合物０．４３部及びモノクロロベンゼン２４．００部を反応器に仕込み、２３℃で３０分間攪拌した。その後、式（Ｉ−２−ｃ）で表される安息香酸銅０．０３部を添加し、１００℃程度まで昇温した後、同温度で１時間攪拌した。得られた反応物を濃縮した後、得られた濃縮物に、クロロホルム４５部及びイオン交換水１１．２５部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水１１．２５部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。この水洗操作をさらに５回繰り返した。回収された有機層をろ過した後、得られたろ液を濃縮した。得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル２０．１２部を加えて攪拌した。得られた上澄液を除去し、上澄液除去後の残渣をさらに濃縮した。得られた濃縮物をアセトニトリルに溶解した後、濃縮することにより、式（Ｉ−２３３−ｄ）で表される塩１．２４部を得た。

式（Ｉ−２３３−ｄ）で表される塩０．５２部、式（Ｉ−２−ｅ）で表される化合物０．２６部及びアセトニトリル１５．００部を反応器に仕込み、２３℃で３０分間攪拌した。得られた混合物に、トリエチルアミン０．１２部を仕込み、７５℃で５時間攪拌した。得られた混合物を、２３℃まで冷却し、クロロホルム３０部及びイオン交換水２０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。この水洗操作をさらに５回繰り返した。回収された有機層に活性炭０．５０部を加えて攪拌し、ろ過した。得られたろ液を濃縮し、酢酸エチル１０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル１０部を加えて攪拌した。得られた上澄液を除去し、上澄液除去後の残渣をさらに濃縮した。得られた濃縮物をアセトニトリルに溶解した後、濃縮することにより、式（Ｉ−２３３）で表される塩０．１９部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ４０３．２
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ３３９．１ Example 3 [Synthesis of salt represented by formula (I-233)]

A reactor was charged with 2.98 parts of a salt represented by the formula (I-2-a), 0.43 parts of a compound represented by the formula (I-233-b) and 24.00 parts of monochlorobenzene. For 30 minutes. Thereafter, 0.03 part of copper benzoate represented by the formula (I-2-c) was added, the temperature was raised to about 100 ° C., and the mixture was stirred at the same temperature for 1 hour. After concentrating the obtained reaction product, 45 parts of chloroform and 11.25 parts of ion-exchanged water were added to the obtained concentrate, followed by stirring at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 11.25 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This washing operation was further repeated 5 times. After the collected organic layer was filtered, the obtained filtrate was concentrated. To the obtained concentrate, 20.12 parts of tert-butyl methyl ether was added and stirred. The resulting supernatant was removed, and the residue after removing the supernatant was further concentrated. The obtained concentrate was dissolved in acetonitrile and then concentrated to obtain 1.24 parts of the salt represented by the formula (I-233-d).

A reactor was charged with 0.52 part of a salt represented by the formula (I-233-d), 0.26 part of a compound represented by the formula (I-2-e) and 15.00 parts of acetonitrile at 23 ° C. Stir for 30 minutes. To the obtained mixture, 0.12 part of triethylamine was added and stirred at 75 ° C. for 5 hours. The obtained mixture was cooled to 23 ° C., 30 parts of chloroform and 20 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This washing operation was further repeated 5 times. To the collected organic layer, 0.50 parts of activated carbon was added, stirred and filtered. The obtained filtrate was concentrated, 10 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 10 parts of tert-butyl methyl ether was added and stirred. The resulting supernatant was removed, and the residue after removing the supernatant was further concentrated. The obtained concentrate was dissolved in acetonitrile and then concentrated to obtain 0.19 part of a salt represented by the formula (I-233).
MASS (ESI (+) Spectrum): M ⁺ 403.2
MASS (ESI (−) Spectrum): M ^- 339.1

式（Ｉ−１１５−ａ）で表される塩２．９０部、式（Ｉ−１１５−ｂ）で表される化合物０．５８部及びモノクロロベンゼン２４．００部を反応器に仕込み、２３℃で３０分間攪拌した。その後、式（Ｉ−１１５−ｃ）で表される安息香酸銅０．０４部を添加し、１００℃程度まで昇温した後、同温度で１時間攪拌した。得られた反応物を濃縮した後、得られた濃縮物に、クロロホルム４０部及びイオン交換水１０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。得られた有機層に、イオン交換水１０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。この水洗操作をさらに５回繰り返した。回収された有機層をろ過した後、得られたろ液を濃縮した。得られた濃縮物に、ｔｅｒｔ−ブチルメチルエーテル２０部を加えて攪拌した。得られた上澄液を除去し、上澄液除去後の残渣をさらに濃縮した。得られた濃縮物をアセトニトリルに溶解した後、濃縮することにより、式（Ｉ−１１５−ｄ）で表される塩０．９１部を得た。

式（Ｉ−１１５−ｄ）で表される塩０．５２部、式（Ｉ−１１５−ｅ）で表される化合物０．５２部及びアセトニトリル１５．００部を反応器に仕込み、２３℃で３０分間攪拌した。得られた混合物に、トリエチルアミン０．２４部を仕込み、７５℃で５時間攪拌した。得られた混合物を、２３℃まで冷却し、クロロホルム３０部及びイオン交換水２０部を加え、２３℃で３０分間攪拌した。その後、静置し、分液して有機層を得た。この水洗操作をさらに５回繰り返した。回収された有機層に活性炭０．５０部を加えて攪拌し、ろ過した。得られたろ液を濃縮し、酢酸エチル１０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル１０部を加えて攪拌した。得られた上澄液を除去し、上澄液除去後の残渣をさらに濃縮した。得られた濃縮物をアセトニトリルに溶解した後、濃縮することにより、式（Ｉ−１１５）で表される塩０．３１部を得た。
ＭＡＳＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ６３９．４
ＭＡＳＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ３２３．０ Example 4 [Synthesis of salt represented by formula (I-115)]

A reactor was charged with 2.90 parts of a salt represented by the formula (I-115-a), 0.58 parts of a compound represented by the formula (I-115-b) and 24.00 parts of monochlorobenzene. For 30 minutes. Thereafter, 0.04 part of copper benzoate represented by the formula (I-115-c) was added, the temperature was raised to about 100 ° C., and the mixture was stirred at the same temperature for 1 hour. After concentrating the obtained reaction product, 40 parts of chloroform and 10 parts of ion-exchanged water were added to the obtained concentrate, followed by stirring at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. To the obtained organic layer, 10 parts of ion-exchanged water was added and stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This washing operation was further repeated 5 times. After the collected organic layer was filtered, the obtained filtrate was concentrated. 20 parts of tert-butyl methyl ether was added to the resulting concentrate and stirred. The resulting supernatant was removed, and the residue after removing the supernatant was further concentrated. The obtained concentrate was dissolved in acetonitrile and then concentrated to obtain 0.91 part of a salt represented by the formula (I-115-d).

A reactor was charged with 0.52 part of a salt represented by the formula (I-115-d), 0.52 part of a compound represented by the formula (I-115-e) and 15.00 parts of acetonitrile at 23 ° C. Stir for 30 minutes. The obtained mixture was charged with 0.24 part of triethylamine and stirred at 75 ° C. for 5 hours. The obtained mixture was cooled to 23 ° C., 30 parts of chloroform and 20 parts of ion-exchanged water were added, and the mixture was stirred at 23 ° C. for 30 minutes. Then, it left still and liquid-separated and obtained the organic layer. This washing operation was further repeated 5 times. To the collected organic layer, 0.50 parts of activated carbon was added, stirred and filtered. The obtained filtrate was concentrated, 10 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 10 parts of tert-butyl methyl ether was added and stirred. The resulting supernatant was removed, and the residue after removing the supernatant was further concentrated. The obtained concentrate was dissolved in acetonitrile and then concentrated to obtain 0.31 part of a salt represented by the formula (I-115).
MASS (ESI (+) Spectrum): M ⁺ 639.4
MASS (ESI (-) Spectrum): M ^- 323.0

以下、これらの化合物をその式番号に応じて、「モノマー（ａ１−１−２）」などという。 Resin Synthesis The compounds used for resin synthesis are shown below.

Hereinafter, these compounds are referred to as “monomer (a1-1-2)” or the like according to the formula number.

Synthesis Example 1: [Synthesis of Resin A1]
The monomer (a1-1-3), the monomer (a1-2-3), the monomer (a2-1-1), the monomer (a3-1-1) and the monomer (a3-2-3) are mixed in a molar ratio [ Monomer (a1-1-3): monomer (a1-2-3): monomer (a2-1-1): monomer (a3-1-1): monomer (a3-2-3)] is 30:14 : 6: 20: 30 The mixture was further mixed, and 1.5 mass times of dioxane was further mixed with this monomer mixture with respect to the total mass of all monomers. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were respectively added to 1.00 mol% and 3.00 mol% with respect to the total number of moles of all monomers. It added so that it might become. This was polymerized by heating at 73 ° C. for about 5 hours. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. It is again dissolved in dioxane, poured into a mixed solvent of a large amount of methanol and water to precipitate the resin, and the precipitated resin is filtered and collected twice to perform reprecipitation purification, and the weight average molecular weight is 8 the resin is .1 × 10 ³ was obtained in a yield of 65%. This resin is divided into monomer (a1-1-3), monomer (a1-2-3), monomer (a2-1-1), monomer (a3-1-1) and monomer (a3-2-3), respectively. This is derived from the following structural unit, and is designated as resin A1.

Synthesis Example 2: [Synthesis of Resin A2]
Monomer (a1-1-2), monomer (a1-2-3), monomer (a2-1-1), monomer (a3-1-1) and monomer (a3-2-3) are mixed in a molar ratio [ Monomer (a1-1-2): monomer (a1-2-3): monomer (a2-1-1): monomer (a3-1-1): monomer (a3-2-3)] is 30:14 : 6: 20: 30 The mixture was further mixed, and 1.5 mass times of dioxane was further mixed with this monomer mixture with respect to the total mass of all monomers. Into the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were respectively added to 1.00 mol% and 3.00 mol% with respect to the total number of moles of all monomers. It added so that it might become. This was polymerized by heating at 73 ° C. for about 5 hours. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. Again, it is dissolved in dioxane, poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and collected twice to perform reprecipitation purification, and the weight average molecular weight is 7 A resin of .8 × 10 ³ was obtained with a yield of 68%. This resin is divided into monomer (a1-1-2), monomer (a1-2-3), monomer (a2-1-1), monomer (a3-1-1), and monomer (a3-2-3). This is derived from the following structural unit, and is designated as resin A2.

Synthesis Example 3: [Synthesis of Resin A3]
Monomer (1-1-2), monomer (a2-1-1) and monomer (a3-1-1) are mixed in a molar ratio [monomer (1-1-2): monomer (a2-1-1): Monomer (a3-1-1)] was mixed so as to be 50:25:25, and 1.5 mass times dioxane was further mixed with respect to the total mass of all monomers. To the obtained mixture, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added as initiators in proportions of 1 mol% and 3 mol%, respectively, with respect to the total number of moles of all monomers. Then, this was heated at 80 ° C. for about 8 hours to carry out polymerization. Thereafter, the polymerization reaction solution was poured into a large amount of a mixed solvent of methanol and water (mass ratio methanol: water = 4: 1) to precipitate the resin. This resin was filtered and collected. Again, the obtained resin is dissolved in dioxane, poured into a large amount of methanol / water mixed solvent to precipitate the resin, and the precipitated resin is filtered and recovered three times for reprecipitation purification. A resin having a weight average molecular weight of about 9.2 × 10 ³ was obtained in a yield of 60%. This resin has structural units derived from the following monomers derived from the monomer (1-1-2), the monomer (a2-1-1) and the monomer (a3-1-1), respectively. This is designated as resin A3.

Synthesis Example 4 [Synthesis of Resin A4]
Monomer (a1-1-2), monomer (a1-2-3), monomer (a2-1-1), monomer (a3-2-3) and monomer (a3-1-1) are mixed in a molar ratio ( Monomer (a1-1-2): Monomer (a1-2-3): Monomer (a2-1-1): Monomer (a3-2-3): Monomer (a3-1-1)) is 30:14 : 6: 20: 30 The mixture was mixed and 1.5 mass times dioxane of the total monomer amount was added to make a solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, 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 the resin, and this resin was filtered. The obtained resin was again dissolved in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 7.2. A × 10 ³ copolymer A4 was obtained with a yield of 78%. This resin A4 has the following structural units.

Synthesis Example 5 [Synthesis of Resin A5]
Monomer (a1-1-2), monomer (a1-5-1), monomer (a2-1-1), monomer (a3-2-3) and monomer (a3-1-1) are mixed in a molar ratio ( Monomer (a1-1-2): Monomer (a1-5-1): Monomer (a2-1-1): Monomer (a3-2-3): Monomer (a3-1-1)) is 30:14 : 6: 20: 30 The mixture was mixed and 1.5 mass times dioxane of the total monomer amount was added to make a solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, 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 the resin, and this resin was filtered. The obtained resin was again dissolved in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 7.2. A × 10 ³ copolymer A5 was obtained with a yield of 78%. This resin A5 has the following structural units.

Synthesis Example 6 [Synthesis of Resin X1]
Monomer (a4-1-7) was used as a monomer, and 1.5 mass times dioxane of the total monomer amount was added to prepare a solution. Azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the solution in an amount of 0.7 mol% and 2.1 mol%, respectively, with respect to the total monomer amount, and these were added at 75 ° C. Heated for about 5 hours. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The resin thus obtained was dissolved again in dioxane, and the solution obtained by pouring the solution into a methanol / water mixed solvent was precipitated twice, and the resin was filtered twice to perform the reprecipitation operation twice. 8 × 10 ⁴ resin was obtained with a yield of 77%. This resin has the following structural units, and this is designated as resin X1.

Examples 5 to 20, Comparative Example 1
<Preparation of resist composition>
In the composition shown in Table 11, each component was mixed and dissolved, and further filtered through a fluororesin filter having a pore diameter of 0.2 μm to prepare a resist composition.

酸発生剤Ｚ１：

<Acid generator>
Salt (I)
I-2: salt represented by formula (I-2) I-114: salt represented by formula (I-114) I-233: salt represented by formula (I-233) I-115: formula Hydrochloric acid generator B1-3 represented by (I-115):

Acid generator Z1:

<Resin>
A1: Resin A1
A2: Resin A2
A3: Resin A3
A4: Resin A4
A5: Resin A5
X1: Resin X1
<Basic compound (C): quencher>
C1: 2,6-Diisopropylaniline

＜溶剤＞
プロピレングリコールモノメチルエーテルアセテート ２６５．０部
プロピレングリコールモノメチルエーテル ２０．０部
２−ヘプタノン ２０．０部
γ−ブチロラクトン ３．５部

<Solvent>
Propylene glycol monomethyl ether acetate 265.0 parts Propylene glycol monomethyl ether 20.0 parts 2-heptanone 20.0 parts γ-butyrolactone 3.5 parts

<Manufacture of resist pattern and its evaluation>
An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical Co., Ltd.] was applied onto a 12-inch silicon wafer and baked at 205 ° C. for 60 seconds to obtain a thickness of 780 mm. An organic antireflection film was formed. Subsequently, the resist composition was spin-coated on the organic antireflection film so that the film thickness after drying (pre-baking) was 85 nm.
After applying the resist composition, the obtained silicon wafer was pre-baked (PB) for 60 seconds at a temperature described in the “PB” column of Table 11 with a direct hot plate. Using the ArF excimer laser stepper for immersion exposure [XT: 1900 Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light] on the wafer on which the resist composition film is thus formed, the exposure amount is stepped. The line and space pattern was subjected to immersion exposure. Note that ultrapure water was used as the immersion medium.
After the exposure, post exposure bake (PEB) was performed on the hot plate at the temperature described in the “PEB” column of Table 11 for 60 seconds, and further with a 2.38 mass% tetramethylammonium hydroxide aqueous solution for 60 seconds. Paddle development was performed to obtain a resist pattern.

  In each resist pattern, the exposure amount at which the line width of the space pattern exposed to a line-and-space pattern (7: 3) mask with a pitch width of 160 nm (line pattern mask size is 112 nm and space pattern mask size is 48 nm) is 48 nm. Was defined as effective sensitivity.

<Focus margin evaluation (DOF)>
In the effective sensitivity, a resist pattern is formed by changing the focus stepwise, and a focus range (45.6 to 50.4 nm) in which the line width of the obtained space pattern is 48 nm ± 5% is represented by a line width index ( DOF). The results are shown in Table 12.

  If this resist composition containing the salt of the present invention as an acid generator is used, a resist pattern can be produced with an excellent focus margin. Therefore, the resist composition of the present invention is useful for fine processing of semiconductors, and the salt (I) capable of realizing such a resist composition has industrial applicability.

Claims (8)

A salt represented by the following formula (I):

[In the formula (I),
R ¹ represents an aromatic hydrocarbon group having 6 to 18 carbon atoms which may have a substituent.
R ² represents an acid-decomposable group.
R ³ represents a hydrogen atom or a hydroxy group.
X ¹ and X ² each independently represent the formula (a-g1)

(In the formula (a-g1),
s represents the integer of 0-2.
A ¹⁰ and A ¹¹ each independently represent an aliphatic hydrocarbon group having 1 to 5 carbon atoms.
When s is 2, the plurality of A ¹⁰ may be the same as or different from each other.
X ¹⁰ represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
When s is 2, a plurality of X ¹⁰ may be the same as or different from each other. )
Represents a group represented by
m1 represents 1 or 2, and m2 represents 0 or 1. However, the relationship of m1 + m2 = 2 is satisfied.
When m1 is 2, a plurality of X ¹ may be the same or different, and a plurality of R ² may be the same or different.
A ⁻ represents an organic anion selected from the group consisting of a sulfonate anion, a sulfonylimide anion, a sulfonylmethide anion, and a carboxylate anion. ] The salt according to claim 1, wherein R ² in the formula (I) is an acid-decomposable group represented by the formula (1).

[In Formula (1),
R ^a1 , R ^a2 and R ^a3 each independently represent an alkyl group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R ^a1 and R ^a2 are bonded to each other to form carbon A divalent hydrocarbon group of 2 to 20 is formed. * Represents a bond. ] X ^{1 in the} formula (I) is
s is 1, A ¹⁰ and A ¹¹ are each independently an alkanediyl group having 1 to 5 carbon atoms, and X ¹⁰ is an oxygen atom, and is a group represented by the above formula (a-g1),
The salt according to claim 2, wherein X ² is an alkanediyl group having 1 to 5 carbon atoms. The salt according to any one of claims 1 to 3, wherein R ^{1 in the} formula (I) is a phenyl group which may have a substituent. The salt according to any one of claims 1 to 4,
A resist composition containing a resin that is insoluble or hardly soluble in an alkaline aqueous solution and that can be dissolved in an alkaline aqueous solution by the action of an acid.   Furthermore, the resist composition of Claim 5 containing a basic compound.   Furthermore, the resist composition of Claim 5 or 6 containing a solvent. (1) The process of apply | coating the resist composition in any one of Claims 5-7 on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a 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: