JP2012215839A - Resist composition - Google Patents

Abstract

［式中、
Ｗは、環構成原子として４級窒素原子を１つ含む芳香族性複素環を表す。
ｎが１である場合、Ｒ^１は前記４級窒素原子に結合している１価の基を表す。
ｎが２である場合、Ｒ^１は、置換基を有してもよいアルカンジイル基などを表す。
Ａ^ｎ１−は、ハロゲンイオン又は有機アニオンを表す。］
【選択図】なしA resist composition capable of producing a resist pattern having an excellent cross-sectional shape is provided.
A resist composition comprising (A) a resin, (B) an acid generator comprising a sulfonium salt or an iodonium salt, (X) a salt represented by formula (I), and (D) a solvent. And a method for producing a resist pattern using the resist composition.

[Where:
W represents an aromatic heterocyclic ring containing one quaternary nitrogen atom as a ring constituent atom.
When n is 1, R ¹ represents a monovalent group bonded to the quaternary nitrogen atom.
When n is 2, R ¹ represents an alkanediyl group which may have a substituent.
An ^n1- represents a halogen ion or an organic anion. ]
[Selection figure] None

Description

  The present invention relates to a resist composition and the like.

  In the production of a resist pattern using a resist composition, a coating film obtained by coating the resist composition on a substrate is irradiated with far-ultraviolet light, and an acid is applied to a portion (exposed portion) irradiated with far-ultraviolet light in the coating film. This is carried out by changing the solubility of the exposed portion and the unexposed portion (the portion of the coating film not irradiated with far ultraviolet light) in the developer by the reaction using this acid as a catalyst.

  Such a resist composition includes a compound that generates energy upon irradiation with far ultraviolet light (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. And are contained. Further, the resist composition may contain a basic compound. Patent Document 1 discloses a resist composition containing tetrabutylammonium hydroxide as a resist composition containing such a basic compound.

JP-A-7-28247

  The resist pattern manufactured from the resist composition described in Patent Document 1 may not always be sufficiently satisfied with its shape (cross-sectional shape).

［式（Ｉ）中、
Ｗは、環を構成する原子として４級窒素原子を１つ含む、５又は６員環の芳香族性複素環を表す。
ｎは１又は２を表す。
ｎが１である場合、Ｒ^１は、置換基を有してもよい炭素数１〜１２のアルキル基、置換基を有してもよい炭素数３〜２４の脂環式飽和炭化水素基及び置換基を有してもよい炭素数２〜１２のアルケニル基からなる群より選ばれる、前記４級窒素原子に結合している１価の基を表す。
ｎが２である場合、Ｒ^１は、置換基を有してもよい炭素数１〜８のアルカンジイル基を表す。
ｎ１は、Ａの電荷数を表し、ｎ２はＡ^ｎ１−の個数を表し、ｎ１×ｎ２＝ｎの関係を満たす。Ａ^ｎ１−は、ハロゲンイオン又は有機アニオンを表す。］
〔２〕前記（Ｘ）は、
前記式（Ｉ）のｎが１であり、かつ

で表される部分構造が、以下の式（Ｉ−ａ）で表される構造の塩である、前記〔１〕記載のレジスト組成物。

［式（Ｉ−ａ）中、
Ｒ^２は、酸素原子、硫黄原子又はＮ（Ｒ^１３）で表される基であり、
Ｒ^１０、Ｒ^１１、Ｒ^１２及びＲ^１３はそれぞれ独立に、水素原子又は１価の有機基である。］
〔３〕前記（Ｘ）が、１−メチル−３−メチルイミダゾールカチオン又は１−メチル−３−エチルイミダゾールカチオンを有する塩である、前記〔１〕記載のレジスト組成物。
〔４〕前記式（Ｉ）のＡ^ｎ１−が、ヨウ素アニオン、有機スルホン酸アニオン、有機スルホンアミドアニオン又は有機カルボン酸アニオンである、前記〔１〕〜〔３〕のいずれか記載のレジスト組成物。
〔５〕前記（Ｂ）が、以下の式（Ｂ１）で表される塩からなる酸発生剤である、前記〔１〕〜〔４〕のいずれか記載のレジスト組成物。

［式（Ｂ１）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、炭素数１〜１７の２価の脂肪族飽和炭化水素基を表し、該２価の脂肪族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１価の脂肪族炭化水素基を表し、該１価の脂肪族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に置き換わっていてもよい。
Ｚ⁺は、スルホニウムカチオン又はヨードニウムカチオンを表す。］
〔６〕前記式（Ｂ１）のＬ^b1が、以下の式（ｂ１−１）で表される基である、前記〔５〕記載の組成物。

［式（ｂ１−１）中、
Ｌ^b2は、単結合又は炭素数１〜１５のアルカンジイル基を表す。
左側の＊は、Ｃ（Ｑ¹）（Ｑ²）の炭素原子と結合する結合手であり、右側の＊は、Ｙと結合する結合手である。］
〔７〕前記式（Ｂ１）のＹが、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である、前記〔５〕又は〔６〕記載のレジスト組成物。
〔８〕さらに溶剤を含有する前記〔１〕〜〔７〕のいずれか記載のレジスト組成物。
〔９〕（１）前記〔８〕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）組成物層を露光する工程、
（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。 As a result of intensive studies to solve the above problems, the present inventors have reached the present invention. That is, the present invention includes the following inventions.
[1] A resist composition containing the following (A), (B) and (X).
(A) a resin 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;
(B) an acid generator comprising a sulfonium salt or an iodonium salt;
(X) a salt represented by the formula (I);

[In the formula (I),
W represents a 5- or 6-membered aromatic heterocyclic ring containing one quaternary nitrogen atom as an atom constituting the ring.
n represents 1 or 2.
When n is 1, R ¹ is an alkyl group having 1 to 12 carbon atoms that may have a substituent, an alicyclic saturated hydrocarbon group having 3 to 24 carbon atoms that may have a substituent, and The monovalent group couple | bonded with the said quaternary nitrogen atom chosen from the group which consists of a C2-C12 alkenyl group which may have a substituent is represented.
When n is 2, R < ¹ > represents the C1-C8 alkanediyl group which may have a substituent.
n1 represents the number of charges of A, n2 represents the number of A ⁿ¹⁻ , and satisfies the relationship of n1 × n2 = n. An ^n1- represents a halogen ion or an organic anion. ]
[2] (X)
N in the formula (I) is 1, and

The resist composition according to [1] above, wherein the partial structure represented by the formula (Ia) is a salt having a structure represented by the following formula (Ia).

[In the formula (Ia),
R ² is a group represented by an oxygen atom, a sulfur atom or N (R ¹³ ),
R ¹⁰ , R ¹¹ , R ¹² and R ¹³ are each independently a hydrogen atom or a monovalent organic group. ]
[3] The resist composition according to [1], wherein (X) is a salt having 1-methyl-3-methylimidazole cation or 1-methyl-3-ethylimidazole cation.
[4] The resist composition according to any one of [1] to [3], wherein An ^{n1- in the} formula (I) is an iodine anion, an organic sulfonate anion, an organic sulfonamide anion, or an organic carboxylate anion. .
[5] The resist composition according to any one of [1] to [4], wherein (B) is an acid generator composed of a salt represented by the following formula (B1).

[In the formula (B1),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group constituting the divalent aliphatic saturated hydrocarbon group may be replaced by an oxygen atom or a carbonyl group. .
Y represents a monovalent aliphatic hydrocarbon group having 1 to 18 carbon atoms which may have a substituent, and the methylene group constituting the monovalent aliphatic hydrocarbon group includes an oxygen atom, a sulfonyl group Alternatively, it may be replaced with a carbonyl group.
Z ⁺ represents a sulfonium cation or an iodonium cation. ]
[6] The composition according to [5], wherein L ^{b1 in the} formula (B1) is a group represented by the following formula (b1-1).

[In the formula (b1-1),
L ^b2 represents a single bond or an alkanediyl group having 1 to 15 carbon atoms.
The * on the left side is a bond that bonds to the carbon atom of C (Q ¹ ) (Q ² ), and the * on the right side is a bond that bonds to Y. ]
[7] The resist composition according to [5] or [6], wherein Y in the formula (B1) is an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent.
[8] The resist composition according to any one of [1] to [7], further containing a solvent.
[9] (1) A step of applying the resist composition according to [8] 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,
(4) A method for producing a resist pattern, comprising: a step of heating the composition layer after exposure; and (5) a step of developing the composition layer after heating.

  According to the resist composition of the present invention, a resist pattern having an excellent cross-sectional shape can be produced.

1A and 1B are diagrams schematically showing the cross-sectional shape of a resist pattern, where FIG. 1A shows a good cross-sectional shape, and FIG. 1B shows a cross-sectional shape whose top shape is T-shaped.

The resist composition of the present invention (hereinafter sometimes referred to as “the present resist composition”) contains the salt (X) (hereinafter sometimes referred to as “salt (X)”). . In addition, the resist composition is
(A) A resin that is insoluble or hardly soluble in an aqueous alkaline solution and can be dissolved in an aqueous alkaline solution by the action of an acid (hereinafter referred to as “resin (A)”).
(B) an acid generator (hereinafter referred to as “acid generator (B)” in some cases);
And may contain a basic compound known in the art (hereinafter sometimes referred to as “basic compound (C)”) as necessary.
The resist composition preferably further contains (D) a solvent (hereinafter sometimes referred to as “solvent (D)”).
Hereinafter, with respect to the salt (X), a suitable one will be mainly described. Further, the resin (A), the acid generator (B), the basic compound (C), the solvent (D) and the like are also described as suitable, and a method for preparing the present resist composition containing these, and the present resist A method for producing a resist pattern using the composition 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.

  In the present specification, the “hydrocarbon group” includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group. The aliphatic hydrocarbon group is further classified into a chain type and an alicyclic type.

Of the chain aliphatic hydrocarbon groups (chain hydrocarbon groups), the monovalent one is typically an alkyl group. Examples of the alkyl group include a methyl group (C ₁ ), an ethyl group (C ₂ ), Propyl group (C ₃ ), butyl group (C ₄ ), pentyl group (C ₅ ), hexyl group (C ₆ ), heptyl group (C ₇ ), octyl group (C ₈ ), decyl group (C ₁₀ ) , Dodecyl group (C ₁₂ ), hexadecyl group (C ₁₄ ), pentadecyl group (C ₁₅ ), hexyldecyl group (C ₁₆ ), heptadecyl group (C ₁₇ ) and octadecyl group (C ₁₈ ). Unless particularly limited, this chain hydrocarbon group may contain a carbon-carbon double bond in a part of the alkyl groups exemplified herein, but does not have such a carbon-carbon double bond, etc. Of these, a chain hydrocarbon group, particularly a saturated alkyl group, is preferred. The divalent chain hydrocarbon group corresponds to an alkanediyl group obtained by removing one hydrogen atom from the alkyl group shown here.

Monovalent alicyclic aliphatic hydrocarbon groups (hereinafter sometimes referred to as “alicyclic hydrocarbon groups”) typically remove one hydrogen atom from an alicyclic hydrocarbon. It is a group. The alicyclic hydrocarbon group may be an unsaturated alicyclic hydrocarbon group containing about one carbon-carbon unsaturated bond or an alicyclic saturated hydrocarbon group containing no carbon-carbon unsaturated bond, The alicyclic hydrocarbon group referred to in this specification is preferably saturated. The alicyclic hydrocarbon group may be monocyclic or polycyclic. Here, an alicyclic hydrocarbon group will be illustrated by illustrating an alicyclic hydrocarbon before removing a hydrogen atom. The monocyclic alicyclic hydrocarbon is a cycloalkane represented by the following formulas (KA-1) to (KA-7).

２価の脂環式炭化水素基としては、式（ＫＡ−１）〜式（ＫＡ−２２）の脂環式炭化水素から水素原子を２個取り去った基が挙げられる。 The polycyclic alicyclic hydrocarbon 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 the formula (KA-1) to the formula (KA-22).

In the present specification, the monovalent aromatic hydrocarbon group is typically an aryl group. Specific examples of the monovalent aromatic hydrocarbon 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 And a fluorenyl group (C ₁₃ ). The divalent aromatic hydrocarbon group is typically an arylene group obtained by further removing one hydrogen atom from a monovalent aromatic hydrocarbon group.

  The aliphatic hydrocarbon group may have a substituent. Such substituents are defined each time. Typical examples of the substituent include a halogen atom, an alkoxy group, an acyl group, an aryl group, an aralkyl group, and an aryloxy group.

The halogen atom is a fluorine atom, a chlorine atom, a bromine atom and an iodine atom unless otherwise specified.
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 ).
Specific examples of the acyl group are 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 In addition to those in which an alkyl group such as a group (C ₈ ), decanoyl group (C ₁₀ ) and dodecanoyl group (C ₁₂ ) and a carbonyl group are bonded, an aryl group and a carbonyl group such as a benzoyl group (C ₇ ) Including the combination of
Specific examples of the aryl group are the same as those exemplified as the aryl group of the above-mentioned aromatic hydrocarbon group, and specific examples of the aryloxy group are those in which the aryl group and an oxygen atom are bonded.
Specific examples of the aralkyl group include a benzyl group (C ₇ ), a phenethyl group (C ₈ ), a phenylpropyl group (C ₉ ), a naphthylmethyl group (C ₁₁ ), and a naphthylethyl group (C ₁₂ ).

  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、
Ｗは、環を構成する原子（環構成原子）として４級窒素原子を１つ含む、５又は６員環の芳香族性複素環を表す。
ｎは１又は２を表す。
ｎが１である場合、Ｒ^１は、置換基を有してもよい炭素数１〜１２のアルキル基、置換基を有してもよい炭素数３〜２４の脂環式飽和炭化水素基及び置換基を有してもよい炭素数２〜１２のアルケニル基からなる群より選ばれる、前記正に電荷した窒素原子に結合している１価の基を表す。
ｎが２である場合、Ｒ^１は、置換基を有してもよい炭素数１〜８のアルカンジイル基を表す。
ｎ１は、Ａの電荷数を表し、ｎ２はＡ^ｎ１−の個数を表し、ｎ１×ｎ２＝ｎの関係を満たす。Ａ^ｎ１−は、ハロゲンイオン又は有機アニオンを表す。］
なお、以下の説明において、塩（Ｘ）を構成する

で表されるカチオンを、場合により「カチオン（Ｘ）」といい、
塩（Ｘ）を構成するＡ^ｎ１−で表されるアニオンを、場合により「アニオン（Ｘ）」という。 <Salt (X)>
The salt (X) contained in the resist composition is represented by the formula (I) as described above. Again, formula (I) is shown below.

In formula (I),
W represents a 5- or 6-membered aromatic heterocyclic ring containing one quaternary nitrogen atom as an atom constituting the ring (ring-constituting atom).
n represents 1 or 2.
When n is 1, R ¹ is an alkyl group having 1 to 12 carbon atoms that may have a substituent, an alicyclic saturated hydrocarbon group having 3 to 24 carbon atoms that may have a substituent, and The monovalent group couple | bonded with the said positively charged nitrogen atom chosen from the group which consists of a C2-C12 alkenyl group which may have a substituent is represented.
When n is 2, R < ¹ > represents the C1-C8 alkanediyl group which may have a substituent.
n1 represents the number of charges of A, n2 represents the number of A ⁿ¹⁻ , and satisfies the relationship of n1 × n2 = n. An ^n1- represents a halogen ion or an organic anion. ]
In addition, in the following description, salt (X) is comprised.

The cation represented by is sometimes referred to as “cation (X)”,
The anion represented by An ^{n1 −} constituting the salt (X) is sometimes referred to as “anion (X)”.

As described above, W of the salt (X) is a 5- or 6-membered aromatic heterocyclic ring containing one quaternary nitrogen atom constituting the ring, and the quaternary nitrogen atom has a positive charge. . The aromatic heterocyclic ring here refers to a heterocyclic ring exhibiting aromaticity.
Specific examples of the 5-membered aromatic heterocycle include oxazole ring, thiazole ring, imidazole ring, pyrazole ring, isoxazole ring, thiadiazole ring, oxadiazole ring, triazole ring, and the like. Mention may be made of a ring in which one of them is a quaternary nitrogen atom. Among these, Preferably, an oxazole ring, a thiazole ring and an imidazole ring, more preferably an oxazole ring and an imidazole ring, particularly preferably a ring in which one of the ring constituent atoms of the imidazole ring is a quaternary nitrogen atom. . On the other hand, specific examples of the 6-membered aromatic heterocycle include pyridine ring, pyrimidine ring, pyridazine ring, pyrazine ring and triazine ring, and one of the ring constituent atoms is a quaternary nitrogen atom. A ring is mentioned. Among these, Preferably, the ring whose one of the ring member atoms of a pyridine ring is a quaternary nitrogen atom is mentioned.

この式において、環Ｗの環構成原子のうち、Ｒ^１と結合している原子は４級窒素原子であることを表している。Ｒ１は、置換基を有してもよいアルキル基、置換基を有してもよい脂環式飽和炭化水素基及び置換基を有してもよいアルケニル基からなる群より選ばれる。該アルキル基としては、その炭素数が１〜１２の範囲において、すでに例示したものを含む。該脂環式飽和炭化水素基も、炭素数３〜２４の範囲であり、且つ炭素炭素不飽和結合を有さない範囲で、すでに例示したものを含む。該アルケニル基は、炭素数２〜１２の範囲内で例示したアルキル基から水素原子を２個取り去ったものであり、その具体例は、ビニル基及び１−プロペニル基などである。また、ここに示したアルキル基、脂肪族飽和炭化水素基及びアルケニル基は置換基を有していてもよい。かかる置換基としては例えば、ハロゲン原子、シアノ基、カルボキシル基、アルコキシ基（メトキシ基及びエトキシ基など）、アリール基（フェニル基及びトルイル基など）、アラルキル基（ベンジル基など）、アリールオキシ基（フェノキシ基など）、アルキルチオ基（メチルチオ基及びエチルチオ基など）、カルボキシアルキル基（２−カルボキシエチル基など）、アルコキシカルボニル基（エトキシカルボニル基など）、炭酸エステル基（エトキシカルボニルオキシ基など）、アシル基（アセチル基、プロピオニル基及びベンゾイル基など）、スルホニル基（メタンスルホニル基及びベンゼンスルホニル基など）、アシルオキシ基（アセトキシ基及びベンゾイルオキシ基など）、スルホニルオキシ基（メタンスルホニルオキシ基及びトルエンスルホニルオキシ基など）、ホスホニル基（ジエチルホスホニル基など）、アミド基（アセチルアミノ基及びベンゾイルアミノ基など）、カルバモイル基（Ｎ，Ｎ−ジメチルカルバモイル基など）及び複素環基（ピリジル基、イミダゾリル基及びフラニル基など）などが挙げられるが、塩（Ｘ）の製造上の容易さなどを考慮すると、Ｒ^１が置換基を有さないアルキル基、置換基を有さない脂環式飽和炭化水素基又は置換基を有さないアルケニル基である塩（Ｘ）が好ましい。 Next, R ¹ of the salt (X) will be described. R ¹ differs depending on whether n is 1 or 2.
When n is 1, R ¹ is a monovalent group bonded to a quaternary nitrogen atom that is a ring-constituting atom of W. For example, cation (X) is represented by the following formula.

In this formula, among the ring-constituting atoms of ring W, the atom bonded to R ¹ is a quaternary nitrogen atom. R1 is selected from the group consisting of an alkyl group that may have a substituent, an alicyclic saturated hydrocarbon group that may have a substituent, and an alkenyl group that may have a substituent. Examples of the alkyl group include those already exemplified in the range of 1 to 12 carbon atoms. The alicyclic saturated hydrocarbon group also includes those already exemplified in the range of 3 to 24 carbon atoms and no carbon-carbon unsaturated bond. The alkenyl group is obtained by removing two hydrogen atoms from an alkyl group exemplified in the range of 2 to 12 carbon atoms, and specific examples thereof include a vinyl group and a 1-propenyl group. The alkyl group, aliphatic saturated hydrocarbon group and alkenyl group shown here may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a carboxyl group, an alkoxy group (such as a methoxy group and an ethoxy group), an aryl group (such as a phenyl group and a toluyl group), an aralkyl group (such as a benzyl group), and an aryloxy group ( Phenoxy group), alkylthio group (such as methylthio group and ethylthio group), carboxyalkyl group (such as 2-carboxyethyl group), alkoxycarbonyl group (such as ethoxycarbonyl group), carbonate group (such as ethoxycarbonyloxy group), acyl Groups (such as acetyl, propionyl and benzoyl groups), sulfonyl groups (such as methanesulfonyl and benzenesulfonyl groups), acyloxy groups (such as acetoxy and benzoyloxy groups), sulfonyloxy groups (such as methanesulfonyloxy and Enesulfonyloxy group etc.), phosphonyl group (diethylphosphonyl group etc.), amide group (acetylamino group and benzoylamino group etc.), carbamoyl group (N, N-dimethylcarbamoyl group etc.) and heterocyclic group (pyridyl group, Imidazolyl group, furanyl group, etc.), but considering the ease of production of the salt (X), R ¹ is an alkyl group having no substituent, an alicyclic saturated group having no substituent A salt (X) which is a hydrocarbon group or an alkenyl group having no substituent is preferred.

Ｒ^１のアルカンジイル基は、炭素数がこの範囲において、すでに例示したものを含む。また、このアルカンジイル基が任意に有する置換基は、ｎが１である場合のＲ^１のアルキル基などが任意に有することもある置換基として例示したものと同じである。ただし、ｎが２である塩（Ｘ）についても、該塩（Ｘ）の製造上の容易さなどを考慮すると、Ｒ^１が置換基を有さないアルカンジイル基が好ましい。 On the other hand, when n is 2, R ¹ is an optionally substituted alkanediyl group having 1 to 8 carbon atoms. In this case, R ¹ is a quaternary atom that is a ring-constituting atom of ring W. It may or may not be bonded to the nitrogen atom. For example, among the ring-constituting atoms of two rings W, a cation (X) in which both atoms bonded to R ¹ are quaternary nitrogen atoms is represented by the following formula.

The alkanediyl group of R ¹ includes those already exemplified within this range of carbon number. Moreover, the substituent which this alkanediyl group arbitrarily has is the same as those exemplified as the substituent which the alkyl group of R ¹ and the like when n is 1 may optionally have. However, for the salt (X) where n is 2, considering the ease of production of the salt (X), an alkanediyl group in which R ¹ has no substituent is preferable.

これらのカチオン（Ｘ）の中でも、式（Ｉ−Ｃ−１）〜式（Ｉ−Ｃ−９）及び式（Ｉ−Ｃ−２６）でそれぞれ表されるものが好ましく、式（Ｉ−Ｃ−１）、式（Ｉ−Ｃ−９）及び式（Ｉ−Ｃ−２６）でそれぞれ表されるものがさらに好ましい。 Among cations (X) constituting the salt (X), cations (X) when n is 1 include those shown below.

Among these cations (X), those represented by formula (IC-1) to formula (IC-9) and formula (IC-26) are preferable, and the formula (IC-C- Those represented by 1), formula (IC-9) and formula (IC-26), respectively, are more preferred.

これらのカチオン（Ｘ）の中でも、式（Ｉ−Ｃ−２２）及び式（Ｉ−Ｃ−２５）でそれぞれ表されるものが好ましく、式（Ｉ−Ｃ−２５）で表されるものがさらに好ましい。 On the other hand, among cations (X) constituting the salt (X), cations (X) when n is 2 include those shown below.

Among these cations (X), those represented by formula (IC-22) and formula (IC-25) are preferable, and those represented by formula (IC-25) are further included. preferable.

Next, the anion (X) [A ^n1- ] of the salt (X) will be described with specific examples. Among the anions (X), an anion (X) where n1 is 1, that is, an anion (X) represented by A ⁻ is preferable. When n of cation (X) is 2, salt (X) is composed of 1 equivalent of cation (X) and 2 equivalents of anion (X) where n1 is 1 (n2 is 2). .

Examples of suitable anions (X) when n1 is 1 include the following anions.

  Among the above specific examples, the anion (X) includes halogen ions [(IA-1) to (IA-3)], organic sulfonate anions [(IA-4) to (IA). -6), (IA-23)], organic sulfonamide anions [(IA-7) to (IA-9)] and organic carboxylate anions [(IA-10) to (I -A-19) and (IA-21)] are preferable, and a halogen ion, an organic sulfonate anion, and an organic carboxylate ion are more preferable. Among halogen ions, iodine anions and chlorine anions [(IA-1), (IA-3)] are particularly preferable.

  The cation (X) and the anion (X) constituting the salt (X) have been described above with specific examples and suitable examples. The salt (X) can arbitrarily combine the cation (X) and the anion (X), and here, a suitable combination will be shown. The combinations are shown in Tables 1 and 2, for example. In these tables, the cation (X) represented by the formula (I-C-1) is represented as “(I-C-1)” according to the formula number, and the formula (I— The anion (X) represented by A-1) is represented as “(I-A-1)” or the like according to the formula number.

  Among the salts (X) shown in Table 1 and Table 3, the salts (X) of (I-1) to (I-31), the salts (X) of (I-72) and the salts of (I-74) ( X) is preferred, salt (X) of (I-1) to (I-5), salt (X) of (I-12) to (I-31), salt (X) of (I-72) and The salt (X) of (I-74) is more preferable, the salt of (I-12) to (I-21), the salt (X) of (I-72) and the salt (X) of (I-74) Is more preferable.

Salt (X) is
A raw material salt (1) composed of a cation (X) and an anion other than the anion (X), and
A raw material salt (2) composed of an anion (X) and a cation other than the cation (X) is prepared, and the raw material salt (1) and the raw material salt (2) are reacted to perform ion exchange. Can be manufactured. Further, among the salts (X), for example, 1-alkyl-3-alkylimidazole iodide (1-alkyl-3-alkylimidazole iodide) can be easily obtained from the market. In order to convert the iodine ion constituting the 1-alkyl-3-alkylimidazole iodide into, for example, a sulfonate anion represented by the formula (IA-5), the 1-alkyl-3- A method in which an alkylimidazole iodide is reacted with p-toluenesulfonic acid sodium salt is used.

<Resin (A)>
As described above, the resin (A) contained in the resist composition 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 (hereinafter, sometimes referred to as “acid action characteristic”). ). By containing this resin (A), this resist composition can manufacture a resist pattern by the effect | action of the acid generate | occur | produced from the acid generator (B) mentioned later. 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 labile group (hereinafter sometimes referred to as “acid labile group”) in the molecule. 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.

［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、これらが結合する炭素原子とともに炭素数３〜２０の環を形成する。Ｒ^a1及びＲ^a2が互いに結合して形成される環、アルキル基又は脂環式炭化水素基を構成する−ＣＨ_２−は、−Ｏ−、−Ｓ−又は−ＣＯ−で置き換わっていてもよい。＊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、これらが結合する炭素原子とともに炭素数３〜２０の環を形成する。該１価の炭化水素基及び該Ｒ^ａ２’及びＲ^ａ３’が互いに結合して形成される環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 labile group>
The “acid labile group” means a group that cleaves a leaving group upon contact with an acid to form a hydrophilic group (for example, a hydroxy group or a carboxy group). Examples of the acid labile group include a group represented by the formula (1) (acid labile group (1)) and a group represented by the formula (2) (acid labile group (2)). .

[In the formula (1), R ^a1 , R ^a2 and R ^a3 (R ^{a1 to} R ^a3 ) are each independently an alkyl group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 20 carbon atoms. R ^a1 and R ^a2 are bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded. —CH ₂ — constituting the ring, alkyl group or alicyclic hydrocarbon group formed by combining R ^a1 and R ^a2 with each other may be replaced by —O—, —S— or —CO—. . * 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 carbon atom having 1 to 20 carbon atoms. R ^{a2 ′} and R ^{a3 ′} are bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded. The monovalent hydrocarbon group and the methylene group constituting the ring formed by combining R ^{a2 ′} and R ^{a3 ′} with each other may be replaced with an oxygen atom or a sulfur atom. * Represents a bond. ]

In the acid labile group (1), R ^{a1 to} R ^a3 alkyl groups and alicyclic hydrocarbon groups include those already exemplified in the range of 1 to 20 carbon atoms. However, carbon number of this alicyclic hydrocarbon group becomes like this. Preferably it is the range of 3-16.

In the acid labile group (1), when R ^a1 and R ^a2 are bonded to each other to form a ring, the group represented by —C (R ^a1 ) (R ^a2 ) (R ^a3 ) is as follows: It is a case where it becomes any group of. The number of carbon atoms in the ring formed by combining R ^a1 and R ^a2 is preferably in the range of 3-12.

Examples of the acid labile 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-butoxycarbonyl group), 2- An alkyladamantan-2-yloxycarbonyl group (in the formula (1), R ^a1 and R ^a2 combine to form an adamantyl ring, and R ^a3 is an alkyl group) and 1- (adamantane-1- Yl) -1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are alkyl groups, and R ^a3 is an adamantyl group).

In the acid labile group (2), the hydrocarbon groups of R ^{a1 ′} and R ^{a2 ′} are, for example, an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and the like. 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 labile group (2) include the following groups.

  The monomer (a1) having an acid labile group [preferably an acid labile group (1) and / or an acid labile group (2)] preferably has an acid labile group and a carbon-carbon double bond. More preferably, it is a (meth) acrylic monomer having an acid labile group.

  Of the (meth) acrylic monomers having an acid labile 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)>
A suitable resin (A) obtained using the monomer (a1) having such an alicyclic hydrocarbon group will be described in more 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 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). To express.
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 represented by R ^a6 and R ^a7 , an alkyl group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 10 carbon atoms is preferable, and specific examples thereof are below the upper limit of the carbon number. In the range of, the same thing as already illustrated is included. 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.

Examples of the monomer (a1) capable of deriving the structural unit (a1-1) include those described in JP-A No. 2010-204646. Among the structural units (a1-1) derived from these, the following formula (a1-1-1), formula (a1-1-2), formula (a1-1-3), formula (a1-1-4) ), Formula (a1-1-5), formula (a1-1-6), formula (a1-1-7) and formula (a1-1-8) [formula (a1-1-1) to formula (a1) −1-8)] is preferable, and the structural unit (a1-1) represented by each of the formula (a1-1-1) to the formula (a1-1-4) is preferable. Is more preferable.

  Examples of the monomer represented by the formula (a1-1) include monomers described in JP 2010-204646 A. Monomers represented by the following formulas (a1-1-1) to (a1-1-8) are preferred, and monomers represented by the following formulas (a1-1-1) to (a1-1-4) are more preferred. .

On the other hand, 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, 1 -Ethylcycloheptan-1-yl (meth) acrylate, 1-methylcyclopentan-1-yl (meth) acrylate, 1-isopropylcyclopentan-1-yl (meth) acrylate and the like.
As the structural unit (a1-2), the following formula (a1-2-1), formula (a1-2-2), formula (a1-2-3), formula (a1-2-4), formula (a1) -2-5) and Formula (a1-2-6) [Formula (a1-2-1) to Formula (a1-2-6)] are preferable. Among these, the structural unit (a1-2) represented by each of the formulas (a1-2-3) and (a1-2-4) is more preferable, and the structure represented by the formula (a1-2-3) The unit (a1-2) is more preferable.

  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).

  The structural unit (a1-1) and the structural unit (a1-2), which are preferable structural units (a1), have been described above. However, the resin (A) has a structural unit (a1) other than these. May be. Hereinafter, the structural unit (a1) other than the structural unit (a1-1) and the structural unit (a1-2) will be described with reference to a monomer 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。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)”). . In the resin (A) having the structural unit (a1) derived from the monomer (a1-3), the structural unit (a1) contains a rigid norbornane ring in the main chain of the resin (A). This resist composition containing such a resin (A) tends to be able 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 — ^Represents 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 The methylene group constituting the aliphatic hydrocarbon group may be replaced with 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 Specific examples of the group include 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 cyclohexyl ring and an adamantyl ring.

As a monomer (a1-3), what was described in Unexamined-Japanese-Patent No. 2010-204646 is used, for example. Among these, a monomer represented by any of the following formula (a1-3-1), formula (a1-3-2), formula (a1-3-3) and formula (a1-3-4) ( a1-3) is preferred, the monomer (a1-3) represented by formula (a1-3-2) or (a1-3-4) is more preferred, and the monomer represented by formula (a1-3-2) (A1-3) 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。］ Further, 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)”). Good.

[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. For example, a trifluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert- Examples thereof include a butyl group, a perfluoropentyl group, and a perfluorohexyl group. 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. .
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. The following formula (a1-4-1), formula (a1-4-2), formula (a1-4-3), formula (a1-4-4), formula (a1-4-5), formula (a1) -4-6) and any one of the monomers represented by formula (a1-4-7) [formula (a1-4-1) to formula (a1-4-7)] are preferred, and the formula (a1-4 -1) to monomers represented by formula (a1-4-5) are 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、水素原子、ハロゲン原子又はハロゲン原子を有してもよい炭素数１〜６のアルキル基を表す。
Ｌ^２〜Ｌ^４はそれぞれ独立に、酸素原子、硫黄原子又は^＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−で表される基を表す。ここで、ｋ１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。
ｓ１及びｓ２は、それぞれ独立して、０〜４の整数を表す。] The monomer (a1) having an acid labile group (2) is preferably a (meth) acrylic monomer. For example, a monomer represented by the formula (a1-5) (hereinafter referred to as “monomer (a1-5)” ”).

[In the formula (a1-5),
R ³¹ represents a hydrogen atom, a halogen atom or an alkyl group having 1 to 6 carbon atoms which may have a halogen atom.
L ^{2 to} L ⁴ each independently represent an oxygen atom, a sulfur atom or a group represented by ^* —O— (CH ₂ ) _k1 —CO—O—. Here, k1 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 constituting the alkanediyl group may be replaced with an oxygen atom or a carbonyl group.
s1 and s2 each independently represents an integer of 0 to 4. ]

In formula (a1-5),
R ³¹ is the same as R ^a32 in formula (a1-4), and is preferably a hydrogen atom or a methyl group.
One of L ² and L ³ is preferably an oxygen atom and the other is a sulfur atom.
L ⁴ is an oxygen atom or a sulfur atom, preferably an oxygen atom.
s1 is preferably 1.
s2 is preferably an integer of 0 to 2.
Z ¹ is a single bond, * — (CH ₂ ) _n4 —O— or * — (CH ₂ ) _n4 —CO—O— (each n4 is an integer of 1 to 4, and is preferably 1. Each * is represents a bond to L ^4.) it is.

The following are mentioned as a monomer (a1-5).

  When the resin (A) has a structural unit derived from the monomer (a1-5), the content ratio 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 not having an acid labile group in addition to a structural unit (a1) having an acid labile group (hereinafter, sometimes referred to as “acid stable structural unit”). 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. The resist composition can easily produce 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).
On the other hand, 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 the acid stable structural unit (a2). It is preferable to introduce into the resin (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の整数を表す。）を表し、＊はカルボニル基（−ＣＯ−）との結合手を表す。
Ｒ^a14は、水素原子又はメチル基を表す。
Ｒ^a15及びＲ^a16は、それぞれ独立に、水素原子、メチル基又はヒドロキシ基を表す。
ｏ１は、０〜１０の整数を表す。 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 represents an oxygen atom or ^* —O— (CH ₂ ) _k2 —CO—O— (k2 represents an integer of 1 to 7), and * represents a bond with a carbonyl group (—CO—). Represent.
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, more preferably an oxygen atom or — O—CH ₂ —CO—O—, 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) and formula (a2-1-4) (A2-1) is more preferable, and the acid stable structural unit (a2-1) represented by the formula (a2-1-1) or (a2-1-3) is more preferable.

  When the resin (A) has the acid stable structural unit (a2-1), the content ratio thereof is in the range of 3 to 45 mol% with respect to all the structural units (100 mol%) of the resin (A). Preferably, the range of 5-40 mol% is more preferable, and the range of 5-35 mol% is further 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、アクリロイル基又はメタクリロイル基を表す。
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は同一でも異なっていてもよい。 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 acryloyl group, or methacryloyl. Represents a group.
ma represents an integer of 0 to 4. When ma is an integer of 2 or more, the plurality of R ^a31 may be the same or different.

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 or an ethyl group, and particularly 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 particularly preferably a methoxy group.
ma is preferably 0, 1 or 2, more preferably 0 or 1, and particularly preferably 0.
ma is preferably 0, 1 or 2, more preferably 0 or 1, and particularly preferably 0.

Among the acid stable structural units (a2-0), the following formulas (a2-0-1), (a2-0-2), (a2-0-3) and (a2-0-4) Those represented by either are preferred. The monomer (a1) 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 is preferably in the range of 5 to 90 mol%, and preferably 10 to 85 mol%, based on all units of the resin (A). The range is more preferable, and the range of 15 to 80 mol% is particularly 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。）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は同一でも異なっていてもよい。
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。）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は同一でも異なっていてもよい。
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。）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は同一でも異なっていてもよい。］ 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 the formula (a3-1) is referred to as “acid-stable structural unit (a3-1)”, and what is represented by the formula (a3-2) is “acid-stable structural unit ( a3-2) ”, and the compound represented by formula (a3-3) is referred to as“ acid-stable structural unit (a3-3) ”.

[In the formula (a3-1),
L ^a4 represents an oxygen atom or ^* —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, a plurality of R ^a21 may be the same or different.
In formula (a3-2),
L ^a5 represents an oxygen atom or ^* —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, a plurality of R ^a22 may be the same or different.
In formula (a3-3),
L ^a6 represents an oxygen atom or ^* —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, a plurality of R ^a23 may be the same or different. ]

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.

  In addition, as an acid stable monomer which can derive | lead out this acid stable structural unit (a3), what was described in Unexamined-Japanese-Patent No. 2010-204646 can be mentioned, for example.

When the resin (A) has an acid stable structural unit (a3), the total content thereof is preferably in the range of 5 to 70 mol% with respect to all the structural units of the resin (A), preferably 10 to 65 mol. % Is more preferable, and the range of 10 to 60 mol% is more preferable.
Moreover, when it has an acid stable structural unit (a3), the range of 5-60 mol% is preferable with respect to all the structural units of this resin (A), and each content rate has the range of 5-50 mol%. More preferably, the range of 10-50 mol% is further more preferable.

  As described above, the structural unit (a1-1) or the structural unit (a1-2) suitable as the structural unit (a1) of the resin (A), the acid stable structural unit (a2) or the acid stable structure suitable as the acid stable structural unit. Although the unit (a3) has been described in detail, structural units other than these may be included, and examples of the structural unit include structural units well known in the art. Although the resin (A) having an acid labile group in the molecule has been described here, the resist composition contains a resin having no acid labile group in addition to the resin (A). May be.

<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 for deriving the acid stable structural unit. More preferably, 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 / or the acid-stable structural unit (a3) are derived. Copolymerized with an acid stable monomer. For example, when the resist composition is used for EUV exposure, the monomer (a1) that induces 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.

  The weight average molecular weight of the resin (A) is preferably 2,500 or more (more preferably 3,000 or more), 30,000 or less (more preferably 15,000 or less, still more preferably 1,000 or less, particularly preferably Is 6,000 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.

<Acid generator (B)>
Next, the acid generator (B) contained in the resist composition will be described.
The acid generator (B) is an acid generator composed of a sulfonium salt or an iodonium salt, and examples of the anion of the acid generator (B) include a sulfonate anion, a sulfonylimide anion, and a sulfonylmethide anion.

［式（Ｂ１）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、単結合又は炭素数１〜１７の２価の脂肪族飽和炭化水素基を表し、前記２価の脂肪族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１価の脂肪族炭化水素基を表し、該１価の脂肪族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に置き換わっていてもよい。
Ｚ⁺は、スルホニウムカチオン又はヨードニウムカチオンを表す。］ The acid generator (B) is preferably a fluorine-containing acid generator, more preferably an acid generator represented by the formula (B1) (hereinafter sometimes referred to as “acid generator (B1)”). .

[In the formula (B1),
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 aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group constituting the divalent aliphatic saturated hydrocarbon group is replaced with an oxygen atom or a carbonyl group. May be.
Y represents a monovalent aliphatic hydrocarbon group having 1 to 18 carbon atoms which may have a substituent, and the methylene group constituting the monovalent aliphatic hydrocarbon group includes an oxygen atom, a sulfonyl group Alternatively, it may be replaced with a carbonyl group.
Z ⁺ represents a sulfonium cation or an iodonium cation. ]

Specific examples of the perfluoroalkyl group of Q ¹ and Q ² include those in which all of the hydrogen atoms constituting the alkyl group are replaced by fluorine atoms in the alkyl group having 1 to 6 carbon atoms among the already exemplified alkyl groups. Applicable. Specifically, for example, 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, a perfluorohexyl group, etc. Can be mentioned.
As the acid generator (B1) contained in the resist composition, Q ¹ and Q ² are each independently preferably a trifluoromethyl group or a fluorine atom acid generator (B1). Q ¹ and Q ² An acid generator (B1) in which both are fluorine atoms is more preferred.

Specific examples of the aliphatic hydrocarbon group represented by L ^b1 include the removal of two hydrogen atoms from the alkanediyl group already exemplified and the alicyclic hydrocarbons of the above formulas (KA-1) to (KA-22). Group.

式（ｂ１−１）〜式（ｂ１−６）中、
Ｌ^b2は、単結合又は炭素数１〜１５の２価の脂肪族炭化水素基を表し、該脂肪族炭化水素基は脂肪族飽和炭化水素基が好ましい。
Ｌ^b3は、単結合又は炭素数１〜１２の２価の脂肪族炭化水素基を表し、該脂肪族炭化水素基は脂肪族飽和炭化水素基が好ましい。
Ｌ^b4は、炭素数１〜１３の２価の脂肪族炭化水素基を表し、該脂肪族炭化水素基は脂肪族飽和炭化水素基が好ましい。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、炭素数１〜１５の２価の脂肪族炭化水素基を表し、該脂肪族炭化水素基は脂肪族飽和炭化水素基が好ましい。
Ｌ^b6及びＬ^b7は、それぞれ独立に、炭素数１〜１５の２価の脂肪族炭化水素基を表し、該脂肪族炭化水素基は脂肪族飽和炭化水素基が好ましい。但しＬ^b6及びＬ^b7の合計炭素数の上限は１６である。
Ｌ^b8は、炭素数１〜１４の２価の脂肪族炭化水素基を表し、該脂肪族炭化水素基は脂肪族飽和炭化水素基が好ましい。
Ｌ^b9及びＬ^b10は、それぞれ独立に、炭素数１〜１１の２価の脂肪族炭化水素基を表し、該脂肪族炭化水素基は脂肪族飽和炭化水素基が好ましい。但しＬ^b9及びＬ^b10の合計炭素数の上限は１２である。
本レジスト組成物に用いる酸発生剤としては、これらの中でも、式（ｂ１−１）で表される２価の基をＬ^b1として有する酸発生剤（Ｂ１）が好ましく、Ｌ^b2が単結合又はメチレン基である式（ｂ１−１）で表される２価の基を、Ｌ^b1として有する酸発生剤（Ｂ１）がより好ましい。 Examples of those in which the methylene group constituting the aliphatic hydrocarbon group of L ^b1 is replaced with an oxygen atom or a carbonyl group include the following formulas (b1-1), (b1-2), and (b1-3) ), Formula (b1-4), formula (b1-5), and formula (b1-6) [formula (b1-1) to formula (b1-6)]. In the formulas (b1-1) to (b1-6), “*” indicating a bond is described in accordance with the formula (B1) on the left and right, and the bond on the left is C (Q ¹ ). It is bonded to the carbon atom of (Q ² ), and the right bond is bonded to Y. The same applies to specific examples of the following formulas (b1-1) to (b1-6).

In formula (b1-1) to formula (b1-6),
L ^b2 represents a single bond or a divalent aliphatic hydrocarbon group having 1 to 15 carbon atoms, and the aliphatic hydrocarbon group is preferably an aliphatic saturated hydrocarbon group.
L ^b3 represents a single bond or a divalent aliphatic hydrocarbon group having 1 to 12 carbon atoms, and the aliphatic hydrocarbon group is preferably an aliphatic saturated hydrocarbon group.
L ^b4 represents a C 1-13 divalent aliphatic hydrocarbon group, and the aliphatic hydrocarbon group is preferably an aliphatic saturated hydrocarbon group. However, the upper limit of the total carbon number of L ^b3 and L ^b4 is 13.
L ^b5 represents a divalent aliphatic hydrocarbon group having 1 to 15 carbon atoms, and the aliphatic hydrocarbon group is preferably an aliphatic saturated hydrocarbon group.
L ^b6 and L ^b7 each independently represent a divalent aliphatic hydrocarbon group having 1 to 15 carbon atoms, and the aliphatic hydrocarbon group is preferably an aliphatic saturated hydrocarbon group. However, the upper limit of the total carbon number of L ^b6 and L ^b7 is 16.
L ^b8 represents a divalent aliphatic hydrocarbon group having 1 to 14 carbon atoms, and the aliphatic hydrocarbon group is preferably an aliphatic saturated hydrocarbon group.
L ^b9 and L ^b10 each independently represent a C 1-11 divalent aliphatic hydrocarbon group, and the aliphatic hydrocarbon group is preferably an aliphatic saturated hydrocarbon group. However, the upper limit of the total carbon number of L ^b9 and L ^b10 is 12.
Among these, as the acid generator used in the present resist composition, an acid generator (B1) having a divalent group represented by the formula (b1-1) as L ^b1 is preferable, and L ^b2 is a single bond or The acid generator (B1) having a divalent group represented by the formula (b1-1) which is a methylene group as L ^b1 is more preferable.

L ^b1 is preferably a group represented by any one of formulas (b1-1) to (b1-4), and more preferably any one of formulas (b1-1) to (b1-3). And particularly preferably a group represented by the formula (b1-1).

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.

As above-mentioned, Y represents the C1-C18 aliphatic hydrocarbon group which may have a substituent. Among these aliphatic hydrocarbon groups, Y is preferably an alkyl group or an alicyclic hydrocarbon group, and is an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 3 to 12 carbon atoms, More preferred is an alicyclic hydrocarbon group having 3 to 12 carbon atoms.
When the aliphatic hydrocarbon group of Y has a substituent, the substituent is, for example, a halogen atom (excluding a fluorine atom), a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an aromatic having 6 to 18 carbon atoms. Group represented by a group hydrocarbon 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 (wherein R ^b1 represents a hydrocarbon group having 1 to 16 carbon atoms, j2 represents an integer of 0 to 4, and the like. The aromatic hydrocarbon group and aralkyl group referred to here may further have, for example, an alkyl group, a halogen atom or a hydroxy group.
The methylene group constituting the aliphatic hydrocarbon group for Y may be replaced with a group (divalent group) selected from the group consisting of an oxygen atom, a sulfonyl group and a carbonyl group. Examples of the group in which the methylene group constituting the alicyclic hydrocarbon group is replaced with an oxygen atom, a sulfonyl group or a carbonyl group include, for example, a cyclic ether group (one or two of the methylene groups constituting the alicyclic hydrocarbon group are A group in which an oxygen atom is substituted), a cyclic ketone group (a group in which one or two methylene groups constituting an alicyclic hydrocarbon group are replaced by a carbonyl group), a sultone ring group (which constitutes an alicyclic hydrocarbon group) Two adjacent methylene groups in the methylene group are replaced with oxygen atoms and sulfonyl groups, respectively, and a lactone ring group (two methylene groups adjacent in the methylene group constituting the alicyclic hydrocarbon group, A group in which an oxygen atom and a carbonyl group are substituted, respectively).

これらの中でも、好ましくは式（Ｙ１）〜式（Ｙ１９）及び式（Ｙ２７）〜式（Ｙ２９）のいずれかで表される基であり、より好ましくは式（Ｙ１１）、式（Ｙ１４）、式（Ｙ１５）、式（Ｙ１９）、式（Ｙ２７）、式（Ｙ２８）及び式（Ｙ２９）で表される基であり、さらに好ましくは式（Ｙ１１）及び式（Ｙ１４）で表される基である。 In particular, examples of the alicyclic hydrocarbon group for Y include groups represented by formulas (Y1) to (Y29). Here, the groups represented by the formula (Y12) to the formula (Y26) were each replaced by 1 to 3 methylene groups contained in the alicyclic hydrocarbon group with an oxygen atom, a sulfonyl group, or a carbonyl group. It corresponds to the group. In the groups represented by these formulas (Y1) to (Y29), * represents a bond to L ¹ .

Among these, Preferably it is group represented by either of Formula (Y1)-Formula (Y19) and Formula (Y27)-Formula (Y29), More preferably, Formula (Y11), Formula (Y14), Formula (Y15), groups represented by formula (Y19), formula (Y27), formula (Y28) and formula (Y29), more preferably groups represented by formula (Y11) and formula (Y14). .

Examples of Y of the alicyclic hydrocarbon group having a substituent include the following.

  As already explained, the alicyclic hydrocarbon group of Y is preferably a group having an adamantane ring as shown in formulas (Y1) and (Y2), and when these have a substituent, Is preferably a hydroxy group or an oxo group. That is, as the alicyclic hydrocarbon group having a substituent, a hydroxyadamantyl group and an oxoadamantyl group are particularly preferable as Y.

Specifically, preferred examples of the sulfonate anion include formula (b1-1-1), formula (b1-1-2), formula (b1-1-3), formula (b1-1-4), formula (B1-1-5), formula (b1-1-6), formula (b1-1-7), formula (b1-1-8) and formula (b1-1-9) [hereinafter referred to as "formula (b1 -1-1) to formula (b1-1-1-9) ". ] The sulfonate anion represented by each can be mentioned. In the sulfonic acid anion represented by each of the formula (b1-1-1) to the formula (b1-1-1-9), L ^b1 is preferably a group represented by the formula (b1-1).

  Specific examples of the sulfonate anions represented by formula (b1-1-1) to formula (b1-1-9) include sulfonate anions described in JP 2010-204646 A, for example. it can.

Hereinafter, as a preferable sulfonate anion, L ^b1 is a group represented by the formula (b1-1), and Y is an alicyclic hydrocarbon group represented by the formula (Y1) or the formula (Y2). A specific example is given. Examples of the sulfonate anion in which Y is an unsubstituted alicyclic hydrocarbon group include those represented by the following formulas (b1-s-1) to (b1-s-9), respectively.

Examples of the sulfonate anion in which Y is an alicyclic hydrocarbon group having a hydroxy group include those represented by the following formulas (b1-s-10) to (b1-s-18), respectively.

Examples of the sulfonate anion in which Y is a cyclic ketone group include those represented by the following formulas (b1-s-19) to (b1-s-29), respectively.

Examples of the sulfonate anion in which Y is an alicyclic hydrocarbon group having an aromatic group include those represented by the following formulas (b1-s-30) to (b1-s-35).

Examples of the sulfonate anion in which Y is the lactone ring group or the sulfonate ring group include those represented by the following formulas (b1-s-36) to (b1-s-41).

Y may be an alkyl group. Examples of such a sulfonate anion include those represented by the following formula (b1-s-42).

The cation (Z ⁺ ) contained in the acid generator (B) is an organic sulfonium cation or an organic iodonium cation, preferably an organic sulfonium cation, and more preferably an organic arylsulfonium cation. These organic sulfonium cations and organic iodonium cations function as a light absorbing part as an acid generator.

Z ⁺ in formula (B1) is preferably represented by formula (b2-1) to formula (b2-4), respectively.

In formula (b2-1) to formula (b2-4),
R ^b4 , R ^b5 and R ^b6 each independently represent a hydrocarbon group having 1 to 30 carbon atoms, and among these hydrocarbon groups, an alkyl group having 1 to 30 carbon atoms and an oil having 3 to 18 carbon atoms A cyclic hydrocarbon group and an aromatic hydrocarbon group having 6 to 18 carbon atoms are preferred. The alkyl group may have a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the alicyclic hydrocarbon group includes a halogen atom and a carbon number. The aromatic hydrocarbon group may have 2 to 4 acyl groups or glycidyloxy groups, and the aromatic hydrocarbon group is a halogen atom, a hydroxy group, an alkyl group having 1 to 18 carbon atoms, or a saturated cyclic carbonization having 3 to 18 carbon atoms. You may have a hydrogen group or a C1-C12 alkoxy group.
R ^b7 and R ^b8 each independently represent a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms.
m2 and n2 each independently represent an integer of 0 to 5.
R ^b9 and R ^b10 each independently represent an alkyl group having 1 to 18 carbon atoms or an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or R ^b9 and R ^b10 are a sulfur atom to which they are bonded. Together with each other to form a 3- to 12-membered ring (preferably a 3- to 7-membered ring). The methylene group contained in the ring may be replaced with an oxygen atom, a sulfur atom or a carbonyl group.
R ^b11 represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms.
R ^b9 , R ^b10 and R ^b11 (R ^{b9 to} R ^b11 ) are each independently an aliphatic hydrocarbon group, and when the aliphatic hydrocarbon group is an alkyl group, the number of carbon atoms is 1 to 12. Preferably, when the aliphatic hydrocarbon group is an alicyclic hydrocarbon group, the carbon number thereof is preferably 3-18, and more preferably 4-12.
R ^b12 represents a hydrocarbon group having 1 to 18 carbon atoms. Among the hydrocarbon groups, the aromatic hydrocarbon group is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or 1 to 12 carbon atoms. It may have an alkylcarbonyloxy group.
R ^b11 and R ^b12 may be bonded to each other to form a 3- to 12-membered ring (preferably a 3- to 7-membered ring), and these 3- to 12-membered rings (preferably a 3-membered ring) (Membered ring to 7-membered ring) is an aliphatic ring or a ring in which the methylene group constituting the aliphatic ring is replaced with an oxygen atom, a sulfur atom or a carbonyl group.

^{R b13, R b14, R b15} , R b16, R b17 and R ^b18 (R ^b13 ~R ^b18) are each independently a hydroxy group, an alkyl group or an alkoxy group having 1 to 12 carbon atoms having 1 to 12 carbon atoms Represents.
L ^b11 represents an oxygen atom or a sulfur atom.
o2, p2, s2, and t2 each independently represents an integer of 0 to 5.
q2 and r2 each independently represents an integer of 0 to 4.
u2 represents 0 or 1.
When o2 is 2 or more, the plurality of R ^b13 may be the same or different. When p2 is 2 or more, the plurality of R ^b14 are independent, and when s2 is 2 or more, a plurality of R ^{b13 b15} may be the same or different, and when t2 is 2 or more, a plurality of ^Rb18 may be the same or different.

As a specific example of the alkylcarbonyloxy group for R ^b12 , an acyl group exemplified above and an oxygen atom are bonded.

Preferred examples of the alkyl group ^{represented by} R ^{b9 to} R ^b12 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, and an octyl group. And 2-ethylhexyl group.
Preferable examples of the alicyclic hydrocarbon group represented by R ^{b9 to} R ^b11 include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclodecyl group, 2-alkyladamantan-2-yl group, 1- ( Adamantan-1-yl) alkane-1-yl group and isobornyl group.
Preferred examples of the aromatic hydrocarbon group for R ^b12 include phenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-cyclohexylphenyl group, 4-methoxyphenyl group, And biphenylyl and naphthyl groups.
A group in which an aromatic hydrocarbon group of R ^b12 and an alkyl group are bonded is typically an aralkyl group.
Examples of the ring formed by combining the combination of R ^b9 and R ^b10 include, for example, a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium ring. Etc.
Examples of the ring formed by combining the combination of R ^b11 and R ^b12 include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

  Specific examples of the sulfonium cation and the iodonium cation include those described in JP 2010-204646 A.

式（ｂ２−１−１）中、
Ｒ^b19、Ｒ^b20及びＲ^b21は、それぞれ独立に、ハロゲン原子（より好ましくはフッ素原子）、ヒドロキシ基、炭素数１〜１８の脂肪族炭化水素基又は炭素数１〜１２のアルコキシ基を表す。
該脂肪族炭化水素基の炭素数は１〜１２であると好ましく、炭素数１〜１２のアルキル基及び炭素数４〜１８の脂環式炭化水素基がより好ましく、さらには置換基として、ハロゲン原子、ヒドロキシ基、炭素数１〜１２のアルコキシ基、炭素数６〜１８の芳香族炭化水素基、炭素数２〜４のアシル基又はグリシジルオキシ基を有していてもよい。
ｖ２、ｗ２及びｘ２は、それぞれ独立に０〜５の整数（好ましくは０又は１）を表す。
ｖ２が２以上のとき、複数のＲ^b19は同一でも異なっていてもよく、ｗ２が２以上のとき、複数のＲ^b20は同一でも異なっていてもよく、ｘ２が２以上のとき、複数のＲ^b21は同一でも異なっていてもよい。
なかでも、Ｒ^b19、Ｒ^b20及びＲ^b21は、それぞれ独立に、好ましくは、ハロゲン原子（より好ましくはフッ素原子）、ヒドロキシ基、炭素数１〜１２のアルキル基、又は炭素数１〜１２のアルコキシ基である。 Among the exemplified organic cations, those represented by the formula (b2-1) are preferable, and organic cations represented by the following formula (b2-1-1) [hereinafter referred to as “cation (b2-1-1)” That's it. ] Is more preferable, and triphenylsulfonium cation (in formula (b2-1-1), v2 = w2 = x2 = 0), diphenyltolylsulfonium cation (in formula (b2-1-1), v2 = w2 = 0, x2 = 1 and R ^b21 is a methyl group) or a tolylsulfonium cation (in formula (b2-1-1), v2 = w2 = x2 = 1, and R ^b19 , R ^b20 and More preferably, R ^b21 is a methyl group.

In formula (b2-1-1),
R ^b19 , R ^b20 and R ^b21 each independently represent a halogen atom (more preferably a fluorine atom), a hydroxy group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms or an alkoxy group having 1 to 12 carbon atoms.
The aliphatic hydrocarbon group preferably has 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms and an alicyclic hydrocarbon group having 4 to 18 carbon atoms. You may have an atom, a hydroxy group, a C1-C12 alkoxy group, a C6-C18 aromatic hydrocarbon group, a C2-C4 acyl group, or a glycidyloxy group.
v2, w2 and x2 each independently represent an integer of 0 to 5 (preferably 0 or 1).
When v2 is 2 or more, a plurality of R ^b19 may be the same or different. When w2 is 2 or more, a plurality of R ^b20 may be the same or different. When x2 is 2 or more, a plurality of R ^{b19 b21} may be the same or different.
Among them, R ^b19 , R ^b20 and R ^b21 are preferably each independently a halogen atom (more preferably a fluorine atom), a hydroxy group, an alkyl group having 1 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. It is a group.

  The acid generator (B1) is a combination of the above-described sulfonate anion and organic cation. The above-mentioned anion and cation can be arbitrarily combined. Preferably, any one of the sulfonate anions of (b1-1-1) to (b1-1-9) and the organic of (b2-1-1) Combinations with cations, and combinations of the sulfonate anions of (b1-1-3) to (b1-1-5) with the organic cations of (b2-3) can be mentioned.

The acid generator (B1) is preferably a salt represented by each of the formulas (B1-1) to (B1-17), more preferably an acid generator containing a triphenylsulfonium cation, a formula (B1-1), Formula (B1-2), Formula (B1-3), Formula (B1-6), Formula (B1-7), Formula (B1-11), Formula (B1-12), Formula ( B1-13) and acid generators represented by formula (B1-14), respectively.

The content of the acid generator (B) is preferably 1 part by mass or more and 30 parts by mass or less, more preferably 3 parts by mass or more and 25 parts by mass or less with respect to 100 parts by mass of the resin (A).
In the present resist composition, the acid generator (B) may be a single type or a plurality of types.

<Basic compound (C)>
In addition to salt (X), this resist composition may contain a basic compound (C) different from salt (X). When the basic composition (C) is contained in the resist composition, the content of the basic compound (C) is preferably 200 parts by mass or less with respect to 100 parts by mass of the total content of the salt (X). More preferably, it is 150 parts by mass or less, and more preferably 100 parts by mass or less. When the basic compound (C) is contained, the total content of the basic compound (C) and (X) is preferably 2% by mass or less, more preferably in the solid content of the resist composition. 1% by mass or less. In addition, solid content here is mentioned later.

  The basic compound (C) is preferably a basic amine, an ammonium salt or a combination thereof, and the amine and the ammonium salt preferably have no sulfur atom in the molecule. 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 the formula (C8), more preferably a compound represented by the formula (C1-1).

［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は、互いに同一でも異なってもよい。］

[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, a plurality of R ^{c4 s} may be the same as or different from each other. ]

［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は、互いに同一でも異なってもよい。］

[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, the plurality of R ^c9 may be the same as or different from each other. ]

［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は互いに同一でも異なってもよい。ｐ３が２以上であるとき、複数のＲ^c15は互いに同一でも異なってもよい。
Ｌ^c1は、炭素数１〜６のアルキレン基、−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 are each independently synonymous with R ^c4 .
o3 and p3 each independently represent an integer of 0 to 3, and when o3 is 2 or more, a plurality of R ^{c14 s} may be the same as or different from each other. When p3 is 2 or more, the plurality of R ^c15 may be the same as or different from each other.
L ^c1 represents a C 1-6 alkylene group, —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は互いに同一でも異なってもよい。ｒ３が２以上であるとき、複数のＲ^c19は互いに同一でも異なってもよい。ｓ３が２以上であるとき、複数のＲ^c20は互いに同一でも異なってもよい。
Ｌ^c2は、単結合又は炭素数１〜６のアルキレン基、−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, the plurality of R ^c18 may be the same or different from each other. When r3 is 2 or more, the plurality of R ^c19 may be the same as or different from each other. When s3 is 2 or more, the plurality of R ^c20 may be the same as or different from each other.
L ^c2 represents a single bond or an alkylene 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 include diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, and 4,4′-diamino-3,3′-diethyldiphenylmethane. Isopropyl aniline, and the like, especially 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 and 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 and tetra-n-butylammonium salicylate and choline.

<Solvent (D)>
The solvent (D) contained in the resist composition includes the type and amount of the salt (X) and resin (A) used, the amount of the acid generator (B) [particularly, the type of the acid generator (B1)] and Depending on the amount of the resist composition, an optimum one can be appropriately selected from the viewpoint that in the production of a resist pattern, which will be described later, the applicability when the resist composition is applied on the substrate 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>
Even if this resist composition contains structural components other than salt (X), resin (A), and an acid generator (B), the solvent (D) used as needed, and a basic compound (C). Good. This component is referred to as “component (F)”. Examples of the component (F) include additives widely used in this technical field, such as polymer compounds other than the resin (A), sensitizers, dissolution inhibitors, surfactants, stabilizers and dyes. Can be mentioned.

<Preparation method of the present resist composition>
This resist composition is a mixture of salt (X), resin (A), acid generator (B), solvent (D), basic compound (C) and other components (F) used as necessary. Can be prepared. Moreover, a component (F) may be mixed as needed. In such mixing, 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.
After mixing each component, it is preferable to filter using a filter having a pore size of about 0.01 to 0.2 μm.

  The content ratio of the salt (X) in the resist composition is preferably 10% by mass or less, more preferably 8% by mass or less, and still more preferably 5% by mass or less, based on the solid content of the resist composition. Preferably it is 0.001 mass% or more, More preferably, it is 0.01 mass% or more, More preferably, it is 0.05 mass% or more. In addition, solid content here means 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.

  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 content rate of the acid generator (B) in this resist composition is set to a preferable range with respect to the content of the resin (A). Specifically, the acid generator (B) is preferably 1% by mass or more, more preferably 3% by mass or more, and preferably 30% by mass or less, more preferably based on the content of the resin (A). Is 25% by mass or less.

  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 amount of the present resist composition. It is 9 mass% or less, Preferably it is 99 mass% or less.

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

<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 using an exposure machine;
(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 the present 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 can be washed or an antireflection film can 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 step (2), the resist composition applied on the substrate, that is, the coating film is dried to remove the solvent [solvent (D)]. In the drying process, for example, the solvent (D) is evaporated from the coating film by a heating means using a heating device such as a hot plate (so-called pre-baking), a decompression means using a decompression device, or a combination of these means. Is done. The drying conditions can be selected according to the type of the solvent (D) contained in the resist composition. For example, in 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, by removing the solvent (D) from the coating film, a composition layer is formed on the substrate.

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 those that emit laser light from a far ultraviolet region or a vacuum ultraviolet region by converting the wavelength of laser light from a semiconductor laser or the like 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 is collectively referred to as “exposure”.
As described above, by exposing through a mask, an exposed portion (exposed portion) and an unexposed portion (unexposed portion) are generated in the composition layer. In the composition layer of the exposed portion, the acid generator (B) [preferably, the acid generator (B1)] contained in the composition layer generates an acid upon receiving exposure energy, and further, by the action of the generated acid, Since the acid labile group in the resin (A) is rendered hydrophilic by the deprotection reaction, the resin (A) in the composition layer in the exposed area becomes 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. The solubility of the composition layer in the exposed area and the composition layer in the unexposed area are significantly different from each other in the aqueous alkali solution.

  In step (4), the composition layer after exposure is subjected to heat treatment (so-called post-exposure baking). Such heat treatment is preferably a heating means using a 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 heated composition layer 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 development, the resist pattern is preferably rinsed 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, the present resist composition can manufacture a resist pattern having a good cross-sectional shape, that is, a substantially rectangular cross-sectional shape. In particular, this resist composition can obtain a resist pattern having an extremely excellent cross-sectional shape in the production of resist patterns by electron beam drawing (EB) or EUV exposure.

<Application>
As described above, the present resist composition is suitable not only as a resist composition for electron beam drawing or EUV exposure, but also as a resist composition for KrF excimer laser exposure and a resist composition for ArF excimer laser exposure. It is also suitable.

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) using polystyrene as a standard product.
Column: TSKgel G4000H _XL + TSKgel G2000H _XL
+ 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)

Synthesis Example 1 (Synthesis of Resin A1)
To 11.18 parts of 2-ethyl-2-adamantyl methacrylate, 14.60 parts of p-acetoxystyrene and 3.55 parts of 3-hydroxy-1-adamantyl methacrylate, 28.82 parts of 1,4-dioxane was added. The solution was heated to 87 ° C. Next, 2.96 parts of azobisisobutyronitrile was added as an initiator, and the mixture was kept warm for 6 hours while maintaining about 87 ° C. After cooling, the reaction mixture was poured into a mixed solution of 291.41 parts of methanol and 124.89 parts of ion-exchanged water to precipitate a polymer, and the precipitate was filtered. The resulting precipitate, the same amount of methanol, and 2.93 parts of 4-dimethylaminopyridine were mixed, and the mixture was heated under reflux for 15 hours. After cooling, the resulting reaction solution was neutralized with 2.16 parts of glacial acetic acid, and then poured into a large amount of water to precipitate the resin. The precipitated resin is filtered off, and the resin is dissolved in acetone, and then purified by repeating the reprecipitation operation of pouring into a large amount of water three times, and the weight average molecular weight is about 3.4 × 10 ³ . 27.71 parts of resin were obtained. This resin is referred to as Resin A1.

Synthesis Example 2 (Synthesis of Resin A2)
To 10.54 parts of 2-methyl-2-adamantyl methacrylate, 14.60 parts of p-acetoxystyrene and 3.55 parts of 3-hydroxy-1-adamantyl methacrylate, 47.09 parts of 1,4-dioxane was added. The solution was heated to 87 ° C. Next, 2.96 parts of azobisisobutyronitrile was added as an initiator, and the mixture was kept warm for 6 hours while maintaining about 87 ° C. After cooling, the reaction mixture was poured into a mixed solution of 285.67 parts of methanol and 122.43 parts of ion-exchanged water to precipitate a polymer, and the precipitate was filtered. The resulting precipitate, the same amount of methanol, and 2.93 parts of 4-dimethylaminopyridine were mixed, and the mixture was heated under reflux for 15 hours. After cooling, the resulting reaction solution was neutralized with 2.16 parts of glacial acetic acid, and then poured into a large amount of water to precipitate the resin. The precipitated resin was filtered off, and the resin was dissolved in acetone and then purified by repeating the reprecipitation operation of pouring into a large amount of water three times to obtain a weight average molecular weight of about 3.7 × 10 ³ . 28.15 parts of resin were obtained. This resin is referred to as Resin A2.

Synthesis Example 3 (Synthesis of Resin A3)
1,4-Dioxane 44.12 parts are added to 10.54 parts of 2-methyl-2-adamantyl methacrylate, 14.60 parts of p-acetoxystyrene, and 1.56 parts of styrene to obtain a solution. The temperature was raised to. Next, 0.69 part of azobisisobutyronitrile was added as an initiator, and the mixture was kept warm for 6 hours while maintaining about 87 ° C. After cooling, the reaction mixture was poured into a mixed solution of 267.63 parts of methanol and 114.70 parts of ion-exchanged water to precipitate a polymer, and the precipitate was filtered. The resulting precipitate, the same amount of methanol, and 2.67 parts of 4-dimethylaminopyridine were mixed, and the mixture was heated under reflux for 15 hours. After cooling, 1.31 parts of glacial acetic acid was added to the resulting reaction solution to neutralize it, and then poured into a large amount of water to precipitate the resin. The precipitated resin was filtered off, and the resin was dissolved in acetone, and then purified by repeating the reprecipitation operation of pouring into a large amount of water three times, and the weight average molecular weight was about 3.3 × 10 ³ . 25.16 parts of resin were obtained. This resin is designated as resin A3.

Synthesis Example 4 (Synthesis of Resin A4)
To 11.18 parts of 2-methyl-2-adamantyl methacrylate, 15.09 parts of p-acetoxystyrene and 3.55 parts of 3-hydroxy-1-adamantyl methacrylate, 28.82 parts of 1,4-dioxane was added. The solution was heated to 82 ° C. Next, 0.86 part of azobisisobutyronitrile was added as an initiator, and the mixture was kept warm for 6 hours while maintaining about 82 ° C. After cooling, the reaction mixture was poured into a mixed solution of 291.41 parts of methanol and 124.89 parts of ion-exchanged water to precipitate a polymer, and the precipitate was filtered. The resulting precipitate, the same amount of methanol, and 2.93 parts of 4-dimethylaminopyridine were mixed, and the mixture was heated under reflux for 15 hours. After cooling, 1.31 parts of glacial acetic acid was added to the resulting reaction solution to neutralize it, and then poured into a large amount of water to precipitate the resin. The precipitated resin is filtered off, and the resin is dissolved in acetone and then purified by repeating the reprecipitation operation of pouring into a large amount of water three times, and the weight average molecular weight is about 8.5 × 10 ³ . 22.42 parts of resin were obtained. This resin is designated as resin A4.

Examples 1 to 11 and Comparative Example 1
The components shown in Table 4 below were mixed and dissolved, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

＜樹脂（Ａ）＞
樹脂Ａ１〜樹脂Ａ４ <Acid generator (B)>
Acid generator B1

<Resin (A)>
Resin A1 to Resin A4

化合物Ｘ２：

化合物Ｘ３：

化合物Ｘ４：

化合物Ｘ５：

化合物Ｘ６：

化合物Ｘ７：

<Salt (X)>
Compound X1:

Compound X2:

Compound X3:

Compound X4:

Compound X5:

Compound X6:

Compound X7:

<Basic compound (C)>
Basic compound C1: tetrabutylammonium hydroxide Basic compound C2:

<Solvent>
Propylene glycol monomethyl ether acetate 400.0 parts Propylene glycol monomethyl ether 150.0 parts γ-butyrolactone 5.0 parts

Evaluation as electron beam resist composition A silicon wafer was treated with hexamethyldisilazane at 90 ° C. for 60 seconds on a direct hot plate, and the film thickness after drying the resist composition described in Table 4 Was spin-coated so as to be 0.04 μm. After applying the resist composition, it was pre-baked (PB) for 60 seconds at a temperature shown in Table 4 on a direct hot plate. Each wafer on which the resist film was thus formed was exposed to a line-and-space pattern using an electron beam drawing machine [“HL-800D 50 keV” manufactured by Hitachi, Ltd.] with the exposure amount being changed stepwise. After exposure, post-exposure baking (PEB) was performed for 60 seconds at a temperature shown in Table 4 on a hot plate, and paddle development was further performed for 60 seconds with a 2.38 wt% tetramethylammonium hydroxide aqueous solution.

<Shape evaluation>
A 100 nm line and space pattern was observed with a scanning electron microscope. Then, the cross-sectional shape of the pattern is close to a rectangle and good (FIG. 1A) is “g” (good), and the top shape is close to a T shape (FIG. 1B) is “b”. "(Bad)". The results are shown in Table 5. The conceptual diagram of the resist pattern shown in FIG. 1 schematically shows a cross-sectional shape when one line and space pattern is cut. The resist pattern having an excellent cross-sectional shape corresponding to “g” means that almost all of the cross-sectional shapes were close to rectangular when the cross-sections at a plurality of locations were observed as described above. .

<Resolution evaluation>
In each resist film, a resist pattern is observed with a scanning electron microscope at an exposure amount at which a 100 nm line and space pattern is 1: 1, and a line width of 50 nm is resolved by “e "(Exellent)" means that the line width of 50 nm or less and 60 nm or less is resolved. "G" (good) means that the line width of 60 nm is not resolved. Was evaluated at three levels with “b” (bad).
These results are shown in Table 5.

Example 12 (Evaluation as a resist composition for EUV)
A silicon wafer was processed on a direct hot plate with hexamethyldisilazane at 90 ° C. for 60 seconds, and then the resist solution described in Table 6 was spin-coated so that the film thickness after drying was 0.04 μm. did. After applying the resist solution, it was pre-baked (PB) for 60 seconds at the temperature shown in Table 6 on a direct hot plate. Each wafer on which the resist film was formed in this manner was exposed to a line-and-space pattern using an EUV exposure machine while changing the exposure stepwise. After the exposure, post-exposure baking (PEB) was performed for 60 seconds at a temperature shown in Table 6 on a hot plate, and paddle development was further performed for 60 seconds with a 2.38 wt% tetramethylammonium hydroxide aqueous solution.

<Shape evaluation>
A 30 nm line and space pattern was observed with a scanning electron microscope. Then, the cross-sectional shape of the pattern is close to a rectangle and good (FIG. 1A) is “g” (good), and the top shape is close to a T shape (FIG. 1B) is “b”. "(Bad)". The results are shown in Table 7.

<Resolution evaluation>
In the resist film, the resist pattern is observed with a scanning electron microscope at an exposure amount at which the 30 nm line and space pattern is 1: 1, and the line width of 24 nm is resolved as “e”. (Exellent), “g” (good) that resolves the line width of the line width that exceeds 24 nm and 28 nm or less, and that that does not resolve the line width of 28 nm Evaluation was made at three levels, “b” (bad).
These results are shown in Table 7.

  According to the resist composition of the present invention, since a resist pattern having an excellent shape can be produced, it is extremely useful for fine processing of semiconductors.

Claims (9)

A resist composition containing the following (A), (B) and (X).
(A) a resin 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;
(B) an acid generator comprising a sulfonium salt or an iodonium salt;
(X) a salt represented by the formula (I);

[In the formula (I),
W represents a 5- or 6-membered aromatic heterocyclic ring containing one quaternary nitrogen atom as an atom constituting the ring.
n represents 1 or 2.
When n is 1, R ¹ is an alkyl group having 1 to 12 carbon atoms that may have a substituent, an alicyclic saturated hydrocarbon group having 3 to 24 carbon atoms that may have a substituent, and The monovalent group couple | bonded with the said quaternary nitrogen atom chosen from the group which consists of a C2-C12 alkenyl group which may have a substituent is represented.
When n is 2, R < ¹ > represents the C1-C8 alkanediyl group which may have a substituent.
n1 represents the number of charges of A, n2 represents the number of A ⁿ¹⁻ , and satisfies the relationship of n1 × n2 = n.
An ^n1- represents a halogen ion or an organic anion. ] Said (X) is
N in the formula (I) is 1, and

The resist composition according to claim 1, wherein the partial structure represented by the formula (Ia) is a salt of a structure represented by the following formula (Ia):

[In the formula (Ia),
R ² is a group represented by an oxygen atom, a sulfur atom or N (R ¹³ ),
R ¹⁰ , R ¹¹ , R ¹² and R ¹³ are each independently a hydrogen atom or a monovalent organic group. ]   2. The resist composition according to claim 1, wherein (X) is a salt having 1-methyl-3-methylimidazole cation or 1-methyl-3-ethylimidazole cation. The resist composition according to any one of claims 1 to 3, wherein An ^{n1- in the} formula (I) is an iodine anion, an organic sulfonate anion, an organic sulfonamide anion, or an organic carboxylate anion. The resist composition according to claim 1, wherein (B) is an acid generator represented by the following formula (B1).

[In the formula (B1),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group constituting the divalent aliphatic saturated hydrocarbon group may be replaced by an oxygen atom or a carbonyl group. .
Y represents a monovalent aliphatic hydrocarbon group having 1 to 18 carbon atoms which may have a substituent, and the methylene group constituting the monovalent aliphatic hydrocarbon group includes an oxygen atom, a sulfonyl group Alternatively, it may be replaced with a carbonyl group.
Z ⁺ represents a sulfonium cation or an iodonium cation. ] The composition according to claim 5, wherein L ^{b1 in the} formula (B1) is a group represented by the following formula (b1-1).

[In the formula (b1-1),
L ^b2 represents a single bond or an alkanediyl group having 1 to 15 carbon atoms.
The * on the left side is a bond that bonds to the carbon atom of C (Q ¹ ) (Q ² ), and the * on the right side is a bond that bonds to Y. ]   The resist composition according to claim 5 or 6, wherein Y in the formula (B1) is a monovalent alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent.   Furthermore, the resist composition in any one of Claims 1-7 containing a solvent. (1) The process of apply | coating the resist composition of Claim 8 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 method for producing a resist pattern, comprising a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating.

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