JP6097568B2 - Salt, resist composition and method for producing resist pattern - Google Patents

Description

    The present invention relates to a salt for an acid generator, a resist composition, and a method for producing a resist pattern.

For example, Patent Document 1 describes a resist composition containing a salt represented by the following formula as an acid generator as a salt for an acid generator.

International Publication No. 2011/108667

  In the conventional resist composition, the line edge roughness (LER) at the time of producing the resist pattern may not always be sufficiently satisfied.

The present invention includes the following inventions.
[1] A salt comprising an anion having a group that is cleaved by the action of an alkali developer and a cation having a group that is cleaved by the action of an alkali developer.

［式（Ｂａ）中、Ｒ^３は、フッ素原子を有する炭素数１〜６のアルキル基を表す。］

［式（Ｂｂ）中、Ｒ^４は、フッ素原子を有する炭素数１〜６のアルキル基を表す。
Ｒ^５及びＲ^６は、それぞれ独立に、水素原子又はフッ素原子を表す。］ [2] The salt according to the above [1], wherein the group cleaved by the action of the alkali developer contained in the anion is a group represented by the formula (Ba) or a group represented by the formula (Bb).

[In Formula (Ba), R ³ represents a C 1-6 alkyl group having a fluorine atom. ]

[In formula (Bb), R ⁴ represents a C 1-6 alkyl group having a fluorine atom.
R ⁵ and R ⁶ each independently represents a hydrogen atom or a fluorine atom. ]

［式（Ｉ−Ａ−ａ）及び式（Ｉ−Ａ−ｂ）中、
Ｑ^１及びＱ^２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^１は、単結合又は炭素数１〜１７のアルカンジイル基を表し、該アルカンジイル基に含まれる水素原子はフッ素原子又はヒドロキシ基で置き換わっていてもよく、該アルカンジイル基に含まれるメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。
Ｙは、炭素数３〜１８の２価の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。
Ｒ^３〜Ｒ^６は、それぞれ上記と同じ意味を表す。］ [3] The anion having a group that is cleaved by the action of an alkali developer is the anion represented by the formula (IAa) or the anion represented by the formula (IAb) [1] Or the salt of [2] description.

[In the formulas (IAa) and (IAb),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a single bond or an alkanediyl group having 1 to 17 carbon atoms, a hydrogen atom contained in the alkanediyl group may be replaced with a fluorine atom or a hydroxy group, and a methylene group contained in the alkanediyl group May be replaced by an oxygen atom or a carbonyl group.
Y represents a C3-C18 divalent alicyclic hydrocarbon group, and the methylene group contained in the alicyclic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
R ^{3 to} R ⁶ each have the same meaning as described above. ]

［式（Ｂａ）中、Ｒ^３は、フッ素原子を有する炭素数１〜６のアルキル基を表す。］

［式（Ｂｂ）中、Ｒ^４は、フッ素原子を有する炭素数１〜６のアルキル基を表す。
Ｒ^５及びＲ^６は、それぞれ独立に、水素原子又はフッ素原子を表す。］ [4] Any one of [1] to [3], wherein the group cleaved by the action of an alkali developer contained in the cation is a group represented by the formula (Ba) or a group represented by the formula (Bb): Salt.

[In Formula (Ba), R ³ represents a C 1-6 alkyl group having a fluorine atom. ]

[In formula (Bb), R ⁴ represents a C 1-6 alkyl group having a fluorine atom.
R ⁵ and R ⁶ each independently represents a hydrogen atom or a fluorine atom. ]

[5] The salt according to [4], wherein the cation is a triarylsulfonium cation (provided that at least one of the three aryl groups constituting the cation has a group that is cleaved by the action of an alkali developer). .
[6] An acid generator containing the salt according to any one of [1] to [5] as an active ingredient.
[7] The acid generator according to [6] above and a resin, wherein the resin has an acid-labile group and is insoluble or hardly soluble in an aqueous alkali solution, and acts on the acid to react with the aqueous alkali solution. A resist composition, which is a resin that can be dissolved in
[8] The resist composition according to [7], further containing a basic compound.
[9] (1) A step of applying the resist composition according to [7] or [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.

  If a resist composition containing the salt of the present invention as an acid generator is used, a resist pattern can be produced with excellent line edge roughness (LER).

In the present specification, unless otherwise specified, the following examples of substituents are applied to any chemical structural formula having the same substituents while appropriately selecting the number of carbon atoms. Among the aliphatic hydrocarbon groups, those that can be linear or branched, such as an alkyl group, include any of them. When stereoisomers exist, all stereoisomers are included. In the following examples of substituents, the numerical value attached to “C” indicates the number of carbon atoms of each group.
Further, in the present specification, "(meth) acrylic monomer", _"CH 2 = _CH-CO-" or _{"CH 2 = C (CH 3)} -CO- " at least one monomer having the structure Means. Similarly, “(meth) acrylate” and “(meth) acrylic acid” mean “at least one of acrylate and methacrylate” and “at least one of acrylic acid and methacrylic acid”, respectively.

The hydrocarbon group includes an aliphatic hydrocarbon group and an aromatic hydrocarbon group.
The aliphatic hydrocarbon group includes both a chain type and a cyclic type, and includes a combination of a chain type and an alicyclic aliphatic hydrocarbon group unless otherwise defined. Further, these aliphatic hydrocarbon groups may contain a carbon-carbon double bond in a part thereof, but a saturated group (aliphatic saturated hydrocarbon group) is preferable.

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

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

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

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

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

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

Examples of alkoxy groups include methoxy group (C ₁ ), ethoxy group (C ₂ ), propoxy group (C ₃ ), butoxy group (C ₄ ), pentyloxy group (C ₅ ), hexyloxy group (C ₆ ), heptyl Examples thereof include an oxy group (C ₇ ), an octyloxy group (C ₈ ), a decyloxy group (C ₁₀ ), and a dodecyloxy group (C ₁₂ ).
As the acyl group, an acetyl group (C ₂ ), a propionyl group (C ₃ ), a butyryl group (C ₄ ), a valeryl group (C ₅ ), a hexanoyl group (C ₆ ), a heptanoyl group (C ₇ ), an octanoyl group ( Examples include those in which an alkyl group such as C ₈ ), decanoyl group (C ₁₀ ) and dodecanoyl group (C ₁₂ ) and a carbonyl group are bonded, and those in which an aryl group such as benzoyl group (C ₇ ) and a carbonyl group are bonded. It is done.

Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, and an isobutyryloxy group.
Examples of the aralkyl group include 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 ).
Aryloxy groups include phenyloxy group (C ₆ ), naphthyloxy group (C ₁₀ ), anthryloxy group (C ₁₄ ), biphenyloxy group (C ₁₂ ), phenanthryloxy group (C ₁₄ ) and full Examples include an aryl group such as an oleenyloxy group (C ₁₃ ) and an oxygen atom bonded to each other.

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

  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.

  The saturated hydrocarbon group means a saturated group among the above-described aliphatic hydrocarbon groups, that is, a saturated group among the above-described chain and cyclic aliphatic hydrocarbon groups. Further, the saturated hydrocarbon group may have the same substituent as the aliphatic hydrocarbon group.

Further, "(meth) acrylic monomer" means at least one monomer having a structure of _"CH 2 = _CH-CO-" or _{"CH 2 = C (CH 3)} -CO- ". 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.

  Hereinafter, the components of the resist composition will be described.

<Salt composed of an anion having a group cleaved by the action of an alkali developer and a cation having a group cleaved by the action of an alkali developer>
The salt of the present invention comprises an anion having a group that is cleaved by the action of an alkali developer and a cation having a group that is cleaved by the action of an alkali developer. Hereinafter, this salt may be referred to as “salt (I)”. However, as an anion having a group that is cleaved by the action of an alkali developer, an anion having a group described later that is unstable to an acid is excluded.

The group that is cleaved by the action of an alkali developer refers to a group that is cleaved by the action of an alkali developer in the development step for producing a resist pattern. In other words, it refers to a base dissociable group that decomposes by the action of an alkali and converts it to an alkali-soluble group.
When the anion and cation constituting the salt (I) come into contact with an alkaline developer in the development step, this group is cleaved to form a hydrophilic group (for example, a hydroxy group or a carboxy group).
The term “cleavage” as used in the present application means that the bond is broken and divided into a plurality of molecules, and does not include a ring-opening reaction.

［式（Ｂａ）中、Ｒ^３は、フッ素原子を有する炭素数１〜６のアルキル基を表す。］

［式（Ｂｂ）中、Ｒ^４は、フッ素原子を有する炭素数１〜６のアルキル基を表す。
Ｒ^５及びＲ^６は、それぞれ独立に、水素原子又はフッ素原子を表す。］ The group cleaved by the action of the alkali developer is preferably a group represented by the formula (Ba) or a group represented by the formula (Bb).

[In Formula (Ba), R ³ represents a C 1-6 alkyl group having a fluorine atom. ]

[In formula (Bb), R ⁴ represents a C 1-6 alkyl group having a fluorine atom.
R ⁵ and R ⁶ each independently represents a hydrogen atom or a fluorine atom. ]

  In the formula (Ba) and the formula (Bb), examples of the alkyl group having a fluorine atom include the same as the above-described fluorinated alkyl group, for example, 1,1,1-trifluoroethyl group, perfluoroethyl group. 1,1,1,2,2-pentafluoropropyl group, perfluoropropyl group, 1,1,1,2,2,3,3-heptafluorobutyl group, perfluorobutyl group, 1,1,1, 2,2,3,3,4,4-nonafluoropentyl group, perfluoropentyl group, perfluorohexyl group and the like are preferable.

このような塩基解離性基を有する塩（Ｉ）は、以下の方法で、開裂したことを確認できる。
例えば、塩（Ｉ）を、溶剤に溶解し、アルカリ溶液を添加し、加熱する。これによって、塩基解離性基を、ヒドロキシ基又はカルボキシ基に変換させることができる。ヒドロキシ基又はカルボキシ基の確認方法としては、生成した化合物の酸性度測定、ＮＭＲ測定及びＭＳ測定などが挙げられる。
溶剤としては、ジメチルホルムアミドが好ましい。
アルカリとしては、テトラメチルアンモニウムヒドロキシドが好ましい。 For example, the group represented by the formula (Ba) is cleaved by the action of an alkali to generate a hydroxy group. The group represented by the formula (Bb) is cleaved by the action of an alkali to generate a carboxy group.

It can be confirmed that the salt (I) having such a base dissociable group is cleaved by the following method.
For example, the salt (I) is dissolved in a solvent, an alkaline solution is added and heated. Thereby, a base dissociable group can be converted into a hydroxy group or a carboxy group. Examples of the method for confirming the hydroxy group or carboxy group include acidity measurement, NMR measurement, and MS measurement of the produced compound.
As the solvent, dimethylformamide is preferable.
As the alkali, tetramethylammonium hydroxide is preferable.

［式（Ｉ−Ａ−ａ）及び式（Ｉ−Ａ−ｂ）中、
Ｑ^１及びＱ^２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^１は、単結合又は炭素数１〜１７のアルカンジイル基を表し、該アルカンジイル基に含まれる水素原子はフッ素原子又はヒドロキシ基で置き換わっていてもよく、該アルカンジイル基に含まれるメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。
Ｙは、炭素数３〜１８の２価の脂環式炭化水素基を表し、該脂環式炭化水素基に含まれるメチレン基は、酸素原子又はカルボニル基で置き換わっていてもよい。
Ｒ^３〜Ｒ^６は、それぞれ上記と同じ意味を表す。］ The anion having a group that is cleaved by the action of an alkaline developer is preferably an anion represented by the formula (IAa) or an anion represented by the formula (IAb).

[In the formulas (IAa) and (IAb),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ represents a single bond or an alkanediyl group having 1 to 17 carbon atoms, a hydrogen atom contained in the alkanediyl group may be replaced with a fluorine atom or a hydroxy group, and a methylene group contained in the alkanediyl group May be replaced by an oxygen atom or a carbonyl group.
Y represents a C3-C18 divalent alicyclic hydrocarbon group, and the methylene group contained in the alicyclic hydrocarbon group may be replaced with an oxygen atom or a carbonyl group.
R ^{3 to} R ⁶ each have the same meaning as described above. ]

In formula (IAa) and formula (IAB), examples of the perfluoroalkyl group include trifluoromethyl group, perfluoroethyl group, perfluoropropyl group, perfluoroisopropyl group, perfluorobutyl group, perfluorosec. -Butyl group, perfluoro tert-butyl group, perfluoropentyl group, perfluorohexyl group and the like can be mentioned.
Q ¹ and Q ² are preferably a trifluoromethyl group or a fluorine atom, and more preferably a fluorine atom.

Examples of the group in which the methylene group contained in the alkanediyl group represented by L ¹ is replaced by an oxygen atom or a carbonyl group are represented by any of the following formulas (b1-1) to (b1-7). Groups. L ¹ is preferably a group represented by any one of formulas (b1-1) to (b1-4), more preferably a group represented by formula (b1-1) or formula (b1-3). is there. In addition, Formula (b1-1)-Formula (b1-7) have described the right and left according to Formula (I), and among the two bonds shown by *, the left bond is C (Q ¹ ) It is bonded to the carbon atom of (Q ² ). The same applies to specific examples of the following formulas (b1-1) to (b1-7).

［式（ｂ１−１）〜式（ｂ１−７）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。
Ｌ^ｂ３は、単結合又は炭素数１〜１２のアルカンジイル基を表す。
Ｌ^ｂ４は、炭素数１〜１３のアルカンジイル基を表す。但しＬ^ｂ３及びＬ^ｂ４の合計炭素数の上限は１３である。
Ｌ^ｂ５は、炭素数１〜１５のアルカンジイル基を表す。
Ｌ^ｂ６は、単結合又は炭素数１〜１５のアルカンジイル基を表す。
Ｌ^ｂ７は、炭素数１〜１５のアルカンジイル基を表す。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のアルカンジイル基を表す。
Ｌ^ｂ９及びＬ^ｂ１０は、それぞれ独立に、炭素数１〜１１のアルカンジイル基を表す。但しＬ^ｂ９及びＬ^ｂ１０の合計炭素数の上限は１２である。
Ｌ^ｂ１１は、単結合又は炭素数１〜１３のアルカンジイル基を表す。
Ｌ^ｂ１２は、炭素数１〜１４のアルカンジイル基を表す。但しＬ^ｂ１１及びＬ^ｂ１２の合計炭素数の上限は１４である。］

[In Formula (b1-1) to Formula (b1-7),
L ^b2 represents a single bond or an alkanediyl group having 1 to 15 carbon atoms.
L ^b3 represents a single bond or an alkanediyl group having 1 to 12 carbon atoms.
L ^b4 represents an alkanediyl group having 1 to 13 carbon atoms. However, the upper limit of the total carbon number of L ^b3 and L ^b4 is 13.
L ^b5 represents an alkanediyl group having 1 to 15 carbon atoms.
L ^b6 represents a single bond or an alkanediyl group having 1 to 15 carbon atoms.
L ^b7 represents an alkanediyl group having 1 to 15 carbon atoms. However, the upper limit of the total carbon number of L ^b6 and L ^b7 is 16.
L ^b8 represents an alkanediyl group having 1 to 14 carbon atoms.
L ^b9 and L ^b10 each independently represent an alkanediyl group having 1 to 11 carbon atoms. However, the upper limit of the total carbon number of L ^b9 and L ^b10 is 12.
L ^b11 represents a single bond or an alkanediyl group having 1 to 13 carbon atoms.
L ^b12 represents an alkanediyl group having 1 to 14 carbon atoms. However, the upper limit of the total carbon number of L ^b11 and L ^b12 is 14. ]

Among them, L ¹ is preferably a divalent group represented by the formula (b1-1), and L ^b2 is represented by the formula (b1-1) in which a single bond or an alkanediyl group having 1 to 6 carbon atoms is used. A divalent group, that is, * —CO—O— (CH ₂ ) _u — (u represents an integer of 0 to 6, and * represents a bond to —C (Q ¹ ) (Q ² ) —) The divalent group represented by the formula (b1-1) which is a single bond or a methylene group, that is, * —CO—O— and * —CO—O—CH ₂ — is more preferable.

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

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

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

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

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

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

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

Examples of L ¹ in which a hydrogen atom is substituted with a fluorine atom or a hydroxy group include the following.

The divalent alicyclic hydrocarbon group is preferably a group represented by the following.

Examples of the group in which the methylene group contained in the divalent alicyclic hydrocarbon group is replaced with an oxygen atom or a carbonyl group include groups represented by the following.

As an anion represented by a formula (IAa), the following are mentioned, for example.

Examples of the salt represented by the formula (IAB) include the following salts.

Next, the cation constituting the salt (I) will be described.
Examples of the cation constituting the salt (I) include an onium cation having a group that is cleaved by the action of an alkali developer, such as a sulfonium cation, an iodonium cation, an ammonium cation, a benzothiazolium cation, and a phosphonium cation. Among these, a sulfonium cation and an iodonium cation are preferable, and an arylsulfonium cation is more preferable.

More preferably, the cation constituting the salt (I) is an organic cation represented by any one of the following formulas (b2-1) to (b2-4) (hereinafter, depending on the number of each formula depending on the case). "Cation (b2-1)", "Cation (b2-2)", "Cation (b2-3)" and "Cation (b2-4)"] provided that the alkaline developer is used. It has at least one group that can be cleaved by action as a substituent.

[In Formula (b2-1),
R ^{b4 to} R ^b6 are each independently an aliphatic hydrocarbon group having 1 to 30 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or an alkali developer. Represents a group that is cleaved by the action of The hydrogen atom contained in the aliphatic hydrocarbon group is a hydroxyl group, a halogen atom, an alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group that is cleaved by the action of an alkali developer. The hydrogen atom contained in the saturated cyclic hydrocarbon group may be substituted with a halogen atom, an acyl group having 2 to 4 carbon atoms, a glycidyloxy group or a group that is cleaved by the action of an alkali developer. The aromatic hydrocarbon group may be a halogen atom, a hydroxy group, an aliphatic hydrocarbon group having 1 to 18 carbon atoms, a saturated cyclic hydrocarbon group having 3 to 18 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or It may be substituted with a group that is cleaved by the action of an alkali developer. R ^b4 and R ^b5 may be combined to form a ring that may have a hetero atom. However, it has at least one group as a substituent that is cleaved by the action of an alkali developer.

In formula (b2-2),
R ^b7 and R ^b8 each independently represent a hydroxyl group, a halogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a group that is cleaved by the action of an alkali developer. However, it has at least one group as a substituent that is cleaved by the action of an alkali developer.
m2 and n2 each independently represent an integer of 0 to 5. When m2 is an integer of 2 or more, the plurality of R ^b7 may be the same or different from each other, and when n2 is an integer of 2 or more, the plurality of R ^b8 are the same or different from each other. May be.

In formula (b2-3),
R ^b9 and R ^b10 each independently represent an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or a group that is cleaved by the action of an alkali developer.
R ^b11 is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group that is cleaved by the action of an alkali developer. Represents.
In R ^{b9 to} R ^b11 , the alkyl group preferably has 1 to 12 carbon atoms. As for carbon number of this alicyclic hydrocarbon group, 4-12 are preferable.
R ^b12 represents an alkyl group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, or a group that is cleaved by the action of an alkali developer, The hydrogen atom contained in 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 an alkyl group having 1 to 12 carbon atoms. It may be substituted with an alkylcarbonyloxy group or a group that is cleaved by the action of an alkali developer.
R ^b9 and R ^b10 and / or R ^b11 and R ^b12 are independently bonded to each other, and together with the atoms to which they are bonded, a 3-membered to 12-membered ring (preferably a 3-membered to 7-membered ring) Ring), and the methylene group contained in these rings may be replaced by an oxygen atom, a sulfur atom or a carbonyl group.
However, it has at least one group as a substituent that is cleaved by the action of an alkali developer.

In formula (b2-4),
R ^{b13 to} R ^b18 each independently represent a hydroxy group, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a group that is cleaved by the action of an alkali developer.
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 an integer of 2 or more, the plurality of R ^b13 may be the same or different from each other. When p2 is an integer of 2 or more, the plurality of R ^b14 are the same or different from each other. When s2 is an integer of 2 or more, the plurality of R ^b17 may be the same or different from each other. When t2 is an integer of 2 or more, the plurality of R ^b18 are the same as each other. When q2 is an integer of 2 or more, the plurality of R ^b15 may be the same or different from each other. When r2 is an integer of 2 or more, the plurality of R ^b16 are They may be the same or different.
However, it has at least one group as a substituent that is cleaved by the action of an alkali developer. ]

The alkylcarbonyloxy group in R ^b12 is a group in which the 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.
Preferred 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- ( And adamantane-1-yl) -1-alkyl and isobornyl groups.
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 the 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 organic cation represented by each of the formulas (b2-1) to (b2-4) include cation derivatives described in JP 2010-204646 A. Among these, a cation (b2-1), a cation (b2-2), and a cation (b2-3) are preferable, and a cation (b2-1) is more preferable. Specific examples of cation (b2-2) and cation (b2-3) are given below. In addition, the specific example of a cation (b2-1) will mention later the more preferable specific example of a cation (b2-1-1).

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

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

［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、炭素数１〜１２のアルコキシ基又はアルカリ現像液の作用により開裂する基を表す。また、Ｒ^ｂ１９〜Ｒ^ｂ２１から選ばれる２つが一緒になってヘテロ原子を有してもよい環を形成してもよい。
この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、グリシジルオキシ基又はアルカリ現像液の作用により開裂する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、炭素数１〜１２のアルコキシ基又はアルカリ現像液の作用により開裂する基である。但し、アルカリ現像液の作用により開裂する基を置換基として、少なくとも一つ有する。］ As described above, among the cations constituting the salt (I), the cation (b2-1) is preferable, and at least one of the three aryl groups constituting the cation is an alkali. More preferably, it has a group that is cleaved by the action of the developer. Such a triarylsulfonium cation is an organic cation represented by the following formula (b2-1-1) [hereinafter referred to as “cation (b2-1-1)”. ].

[In the 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, an alkoxy group having 1 to 12 carbon atoms or an alkali development. A group that is cleaved by the action of a liquid. It is also possible to form two of which may have a hetero atom together ring selected from R ^b19 to R ^b21.
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. It has an atom, a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, an acyl group having 2 to 4 carbon atoms, a glycidyloxy group, or a group that is cleaved by the action of an alkali developer. You may do it.
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. Alternatively, it is a group that is cleaved by the action of an alkali developer. However, it has at least one group as a substituent that is cleaved by the action of an alkali developer. ]

The alkyl group of R ^{b19 to} R ^b21 preferably has a carbon number of 1 to 12, and the hydrogen atom contained in the alkyl group is a hydroxy group, an alkoxy group of 1 to 12 carbon atoms or an aromatic group of 6 to 18 carbon atoms. It may be substituted with a hydrocarbon group.
The alicyclic hydrocarbon group of R ^{b19 to} R ^b21 preferably has 4 to 18 carbon atoms, and the hydrogen atom contained in the alicyclic hydrocarbon group is a halogen atom or an acyl group having 2 to 4 carbon atoms. Alternatively, it may be substituted with a glycidyloxy group.
Among these, R ^{b19 to} 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.

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

As described above, the salt (I) has been described by dividing it into an anion having a group that is cleaved by the action of an alkali developer and a cation having a group that is cleaved by the action of an alkali developer. A combination of an anion having a group that is cleaved by the action of an alkali developer and a cation having a group that is cleaved by the action of an alkali developer. These anions and cations can be arbitrarily combined.
Specific examples of this combination include those listed in Tables 1 to 3.

  From Tables 1 to 3, the more preferable salt (I) among the salts (I) represented by the combination of the sulfonate anion and the organic cation is specifically shown as follows.

［式中、Ｑ^１、Ｑ^２、Ｌ^１及びＹそれぞれ上記と同じ意味を表す。
Ｒ^３ｃ及びＲ^３ａは、それぞれ独立にＲ^３と同じ意味を表す。］ The salt (I) can be produced, for example, by the following method and a method analogous thereto. In addition, the definition of the substituent in the following formula is synonymous with the above.
For example, the salt represented by the formula (IA) will be described as an example.

[Wherein, Q ¹ , Q ² , L ¹ and Y each have the same meaning as described above.
R ^3c and R ^3a each independently represent the same meaning as R ³ . ]

式（ＩＡ−ｂ）で表される化合物としては、ヘプタフルオロブチリルクロリドなどが挙げられる。 First, by reacting a compound represented by the formula (IA-a) with a compound represented by the formula (IA-b) under a basic catalyst, a salt represented by the formula (IA-c) is obtained. Can be manufactured. Examples of the solvent include chloroform. Examples of the base catalyst include N-methylpyrrolidine.

Examples of the compound represented by the formula (IA-b) include heptafluorobutyryl chloride.

式（ＩＡ−ｄ）で表される化合物としては、特開２００６−２５７０７８号公報に記載された化合物などが挙げられる。 A salt represented by the formula (IA-f) is produced by reacting a compound represented by the formula (IA-d) with a compound represented by the formula (IA-e) under a basic catalyst. be able to. Examples of the solvent include chloroform. Examples of the base catalyst include N-methylpyrrolidine.

Examples of the compound represented by the formula (IA-d) include compounds described in JP-A-2006-257078.

Producing a salt represented by the formula (IA) by reacting a salt represented by the formula (IA-c) with a compound represented by the formula (IA-f) in the presence of an acid catalyst. Can do. Examples of the solvent include chloroform. Examples of the acid catalyst include hydrochloric acid.

［式中、Ｑ^１、Ｑ^２、Ｌ^１、Ｒ^３ｃ、Ｒ^４、Ｒ^５、Ｒ^６及びＹは、それぞれ上記と同じ意味を表す。］ For example, the salt represented by formula (IB) will be described as an example.

[Wherein, Q ¹ , Q ² , L ¹ , R ^3c , R ⁴ , R ⁵ , R ⁶ and Y each have the same meaning as described above. ]

A salt represented by the formula (IB-b) is produced by reacting a salt represented by the formula (IA-c) with a compound represented by the formula (IB-a) in the presence of an acid catalyst. can do. Examples of the solvent include chloroform. Examples of the acid catalyst include hydrochloric acid.

The salt represented by the formula (IB-d) can be obtained by reacting the salt represented by the formula (IB-b) with the compound represented by the formula (IB-c).

式（ＩＢ−ｅ）で表される化合物としては、以下で表される化合物などが挙げられる。

The salt represented by the formula (IB-f) can be produced by reacting the salt represented by the formula (IB-d) with the compound represented by the formula (IB-e).
Examples of the solvent include acetonitrile.

Examples of the compound represented by the formula (IB-e) include compounds represented by the following.

The salt represented by the formula (IB-g) can be produced by treating the salt represented by the formula (IB-f) with an acid in a solvent.
Examples of the solvent include chloroform and methanol.
Examples of the acid include hydrochloric acid.

The salt represented by the formula (IB-h) can be obtained by reacting the salt represented by the formula (IB-g) with the compound represented by the formula (IB-c).

式（ＩＢ−ｉ）で表される化合物としては、以下で表される化合物などが挙げられる。

The salt represented by the formula (IB) can be produced by reacting the salt represented by the formula (IB-h) with the compound represented by the formula (IB-i).
Examples of the solvent include acetonitrile.

Examples of the compound represented by the formula (IB-i) include compounds represented by the following.

<Acid generator other than salt (I)>
The present resist composition is characterized by containing one or more salts (I) as an acid generator, and the present resist composition is a known acid other than the salt (I) as an acid generator. It may further contain a generator. The acid generator other than the salt (I) may be an ionic acid generator or a nonionic acid generator, but is preferably an ionic acid generator. The ionic acid generator is of course different from the salt (I) in both the cation and the anion constituting the ionic acid generator,
Even an ionic acid generator comprising a combination of the same cation as the organic cation constituting the salt (I) and a known anion other than the sulfonate anion constituting the salt (I),
It may be an ionic acid generator composed of a combination of the same anion as the sulfonate anion constituting the salt (I) and a known cation other than the organic cation constituting the salt (I).
Hereinafter, the acid generator other than the salt (I) contained in the resist composition is sometimes referred to as “acid generator (B)”.

  As an acid generator (B), what is represented by a formula (B1-1)-a formula (B1-24) is mentioned, for example. Among them, those containing a triarylsulfonium cation are preferable. Formula (B1-1), Formula (B1-2), Formula (B1-3), Formula (B1-6), Formula (B1-7), Formula (B1- 11), formula (B1-12), formula (B1-13), formula (B1-14), formula (B1-18), formula (B1-19), formula (B1-20), formula (B1-21) ), Formula (B1-22), formula (B1-23) and salt represented by formula (B1-24), respectively, are more preferable.

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

  The resin (A) having acid action characteristics has an acid labile group (hereinafter, sometimes referred to as “acid labile group”) in its 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、炭素数３〜２０の脂環式炭化水素基又はこれらを組み合わせた基を表すか、Ｒ^ａ１及びＲ^ａ２は互いに結合して炭素数２〜２０の２価の炭化水素基を形成する。＊は結合手を表す。］ <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 Formula (1),
R ^a1 , R ^a2 and R ^a3 (R ^{a1 to} R ^a3 ) each independently represent an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a combination thereof. R ^a1 and R ^a2 are bonded to each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms. * Represents a bond. ]

［式（２）中、
Ｒ^ａ１’及びＲ^ａ２’は、それぞれ独立に、水素原子又は炭素数１〜１２の１価の炭化水素基を表し、Ｒ^ａ３’は、炭素数１〜２０の炭化水素基を表すか、Ｒ^ａ２’及びＲ^ａ３’は互いに結合して炭素数２〜２０の２価の炭化水素基を形成する。該１価の炭化水素基及び該２価の炭化水素基を構成するメチレン基は、酸素原子又は硫黄原子に置き換わってもよい。＊は結合手を表す。］

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

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

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

Examples of the acid 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-butyloxycarbonyl group), 2-alkyladamantan-2-yloxycarbonyl group (in formula (1), R ^a1 and R ^a2 are bonded to form an adamantane 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).

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

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

  The monomer (a1) is preferably a monomer having an acid labile group and a carbon-carbon double bond, and more preferably a (meth) acrylic monomer having an acid labile group.

  Among them, the monomer (a1) having an acid labile group (1) and / or an acid labile group (2) is preferable, and having an acid labile group (1) and / or an acid labile group (2) (meta ) Acrylic monomers are more preferred.

  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−（ＣＨ_２）_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−（ＣＨ_２）_ｋ１−ＣＯ−Ｏ−（ｋ１は前記と同義である。）で表される基を表す。
Ｒ^ａ５は、水素原子又はメチル基を表す。
Ｒ^ａ７は、炭素数１〜１０の脂肪族炭化水素基を表す。
ｎ１は０〜１０の整数を表す。
ｎ１’は０〜３の整数を表す。］ <Preferred structural unit (a1)>
The resin (A) having a suitable structural unit (a1) obtained by using the monomer (a1) having such an alicyclic hydrocarbon group will be further described in detail. Among the resins (A), a structural unit represented by the formula (a1-1) (hereinafter sometimes referred to as “structural unit (a1-1)”) or a structural unit represented by the formula (a1-2) A resin (A) having (hereinafter referred to as “structural unit (a1-2)” in some cases) is preferable. Such resin (A) may have the structural unit (a1-1) as a single species, may have a plurality of types, or may have the structural unit (a1-2) as a single species. In addition, a plurality of types may be included, and the structural unit (a1-1) and the structural unit (a1-2) may be combined.

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

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

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

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

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

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

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

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

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

［式（ａ１−３）中、
Ｒ^ａ９は、水素原子、置換基（例えばヒドロキシ基）を有していてもよい炭素数１〜３の脂肪族炭化水素基、カルボキシ基、シアノ基、又は−ＣＯＯＲ^ａ１３で表される基を表し、Ｒ^ａ１３は、炭素数１〜８の脂肪族炭化水素基を表し、該脂肪族炭化水素基に含まれる水素原子はヒドロキシ基など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は互いに一緒になってこれらが結合している炭素原子と共に環を形成する。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 represented by the following formula (a1-3) (hereinafter sometimes referred to as “structural unit (a1-3)”). Since the resin (A) having the structural unit (a1-3) contains a rigid norbornane ring in the main chain, the resist composition containing such a resin (A) has a dry etching resistance. There is a tendency that an excellent resist pattern can be produced.

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

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

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

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

  When the resin (A) has the structural unit (a1-3), the content is preferably in the range of 10 to 95 mol% with respect to all the structural units of the resin (A), and is 15 to 90 mol%. The range is more preferable, and the range of 20 to 85 mol% is more preferable.

［式（ａ１−４）中、
Ｒ^１０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。
Ｒ^１１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Ｒ^１１は互いに同一であっても異なってもよい。
Ｒ^１２及びＲ^１３はそれぞれ独立に、水素原子又は炭素数１〜１２の炭化水素基を表す。
Ｘ^ａ２は、置換基を有していてもよい炭素数１〜１７の脂肪族炭化水素基又は単結合を表し、該脂肪族炭化水素基を構成するメチレン基は、酸素原子、硫黄原子、カルボニル基、スルホニル基又は−Ｎ（Ｒ^ｃ）−（ただし、Ｒ^ｃは、水素原子又は炭素数１〜６のアルキル基を表す）で表される基に置き換わっていてもよい。
Ｙ^ａ３は、置換基を有していてもよい炭素数１〜１８の炭化水素基を表す。］ The resin (A) may have a structural unit represented by the following formula (a1-4) (hereinafter sometimes referred to as “structural unit (a1-4)”).

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

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. preferable.
The acyl group and acyloxy group of R ¹¹ also 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 already exemplified in the range of 1 to 18 carbon atoms and Contains any of the aromatic hydrocarbon groups.
Aliphatic hydrocarbon group is a divalent chain hydrocarbon group of X ^a2, divalent alicyclic hydrocarbon group or a chain hydrocarbon group and an alicyclic divalent group and hydrocarbon groups are combined And groups obtained by appropriately combining the groups already exemplified in the range of 1 to 17 carbon atoms.

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

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

［式（ａ１−５）中、
Ｒ^３１は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｌ^１〜Ｌ^３は、オキシ基、チオキシ基又は＊−Ｏ−（ＣＨ_２）_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中に含まれるメチレン基は、オキシ基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。］ Examples of the other structural unit (a1) include a structural unit represented by the formula (a1-5) which is a (meth) acrylic monomer having an acid labile group (2) (hereinafter referred to as “structural unit (a1-5)”. ) ”May be used.

[In the formula (a1-5),
R ³¹ represents a C 1-6 alkyl group which may have a halogen atom, a hydrogen atom or a halogen atom.
L ^{1 to} L ³ represent a group represented by an oxy group, a thioxy group, or * —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 contained in the alkanediyl group may be replaced with an oxy group or a carbonyl group.
s1 and s2 each independently represents an integer of 0 to 4. ]

In formula (a1-5), R ³¹ is preferably a hydrogen atom, a methyl group, or a trifluoromethyl group.
L ¹ is preferably an oxygen atom.
One of L ² and L ³ is preferably an oxygen atom and the other is a sulfur atom.
s1 is preferably 1.
s2 is preferably an integer of 0 to 2.
Z ¹ is preferably a single bond or —CH ₂ —CO—O—.

As the structural unit (a1-5), the following monomers may be mentioned.

  When the resin (A) has the structural unit (a1-5), the content ratio is preferably in the range of 1 to 95 mol% with respect to all the structural units (100 mol%) of the resin (A). The range of -90 mol% is more preferable, and the range of 5-85 mol% is more preferable.

<Acid stable structural unit>
Resin (A) is a structural unit having no acid labile group in addition to the structural unit (a1) containing an acid labile group (hereinafter referred to as “acid stable structural unit” in some cases). Preferably, the derivatizable monomer is referred to as an “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 to 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). When using exposure using a short wavelength ArF excimer laser (wavelength: 193 nm) as an exposure source, an acid stable structural unit represented by the formula (a2-1) described later is used as a resin ( It is preferable to introduce into A). Thus, each of the acid stable structural units (a2) possessed by the resin (A) can be selected according to the exposure source used for producing the resist pattern, but the acid stable structural units possessed by the resin (A) ( a2) may have only one type of acid stable structural unit (a2) suitable for the type of exposure source, and two or more types of acid stable structural unit (a2) suitable for the type of exposure source. Or an acid stable structural unit (a2) suitable for the type of exposure source and a combination of other acid stable structural units (a2).

［式（ａ２−１）中、
Ｌ^ａ３は、酸素原子又は＊−Ｏ−（ＣＨ_２）_ｋ２−ＣＯ−Ｏ−（ｋ２は１〜７の整数を表し、＊はカルボニル基（−ＣＯ−）との結合手を表す。）で表される基を表す。
Ｒ^ａ１４は、水素原子又はメチル基を表す。
Ｒ^ａ１５及びＲ^ａ１６は、それぞれ独立に、水素原子、メチル基又はヒドロキシ基を表す。
ｏ１は、０〜１０の整数を表す。］ One specific example of the acid stable structural unit (a2) is one represented by the following formula (a2-1) (hereinafter sometimes referred to as “acid stable structural unit (a2-1)”).

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

L ^a3 is preferably an oxygen atom or a group represented by —O— (CH ₂ ) _k2 —CO—O—, wherein k2 is an integer of 1 to 4, and more preferably an oxygen atom or — O—CH ₂ —CO—O—, 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) to formula (a2-1-6) is more preferable, and the formula (a2-1-1) or (a2-1-1-) The acid stable structural unit represented by 3) is more preferable.

  When the resin (A) has an acid stable structural unit (a2-1), the content ratio is preferably in the range of 1 to 45 mol%, and 1 to 40 mol% with respect to all the structural units of the resin (A). The range of 2 to 35 mol% is more preferable.

［式（ａ２−０）中、
Ｒ^ａ３０は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｒ^ａ３１は、ハロゲン原子、ヒドロキシ基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜４のアシル基、炭素数２〜４のアシルオキシ基、アクリロイル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 the formula (a2-0),
R ^a30 represents an alkyl group having 1 to 6 carbon atoms 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 and 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), those represented by any of the following formulas (a2-0-1) to (a2-0-4) are preferable. An acid stable monomer capable of deriving such a structural unit is described in, for example, JP 2010-204634 A.

  Acid-stable monomer capable of deriving acid-stable structural unit (a2-0) such as p-hydroxystyrene and p-hydroxy-α-methylstyrene [hereinafter referred to as “acid-stable monomer (a2)” in some cases. ] For the production of the resin (A), an acid stable structural unit represented by the formula (a2-0-1) or the formula (a2-0-2) can be introduced into the resin (A). Is protected with a protecting group such as an acetyl group to form a protected acid stable monomer (a2), and then this protected acid stable monomer (a2) is protected. The resin (A) can also be produced using 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% with respect to all the structural units of the resin (A). Is more preferable, and the range of 15 to 80 mol% is more preferable.

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

［式（ａ３−１）中、
Ｌ^ａ４は、酸素原子又は＊−Ｏ−（ＣＨ_２）_ｋ３−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^ａ１８は、水素原子又はメチル基を表す。
ｐ１は０〜５の整数を表す。
Ｒ^ａ２１は炭素数１〜４の脂肪族炭化水素基を表し、ｐ１が２以上の場合、複数のＲ^ａ２１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−（ＣＨ_２）_ｋ３−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
ｑ１は、０〜３の整数を表す。
Ｒ^ａ２２は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表し、ｑ１が２以上の場合、複数のＲ^ａ２２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−（ＣＨ_２）_ｋ３−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^ａ２０は、水素原子又はメチル基を表す。
ｒ１は、０〜３の整数を表す。
Ｒ^ａ２３は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表し、ｒ１が２以上の場合、複数のＲ^ａ２３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 a group represented by 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, the plurality of R ^a21 may be the same or different.
In formula (a3-2),
L ^a5 represents an oxygen atom or a group represented by * —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
q1 represents an integer of 0 to 3.
R ^a22 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and when q1 is 2 or more, a plurality of R ^a22 may be the same or different.
In formula (a3-3),
L ^a6 represents a group represented by 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, and 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 or different from each other. When q1 is 2, two R ^a22 may be the same or different from each other, and r1 is 2. Two R ^a23 may be the same as 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) are those represented by any of the following formulas (a3-1-1) to (a3-1-4).

Preferable examples of the acid stable structural unit (a3-2) are those represented by any of the following formulas (a3-2-1) to (a3-2-4).

Preferable examples of the acid stable structural unit (a3-3) are those represented by any of the following formulas (a3-3-1) to (a3-3-4).

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

  When the resin (A) has an acid stable structural unit (a3), the content is preferably in the range of 5 to 70 mol%, and preferably 10 to 65 mol% with respect to all the structural units of the resin (A). Is more preferable, and the range of 10 to 60 mol% is more preferable.

<Other acid stable structural units>
The preferred acid stable structural unit (a2) and acid stable structural unit (a3) have been described as the acid stable structural unit possessed by the resin (A). However, the resin (A) contains the acid stable structural unit (a2) and the acid stable structural unit. It may have an acid stable structural unit other than the structural unit (a3). Here, the acid stable structural unit (a4) other than the acid stable structural unit (a2) and the acid stable structural unit (a3) is referred to.

［式（ａ４−１）中、
Ｒ^ａ４１は、炭素数１〜１２の１価の脂肪族炭化水素基又は炭素数６〜１２の１価の芳香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、酸素原子又はカルボニル基に置き換わっていてもよい。Ａ^ａ４１は、置換基を有していてもよい炭素数１〜６のアルカンジイル基又は式（ａ−ｇ１）

（式（ａ−ｇ１）中、
ｓは０又は１を表す。
Ａ^ａ４２及びＡ^ａ４４は、それぞれ独立に、置換基を有していてもよい炭素数１〜５の脂肪族炭化水素基を表す。
Ａ^ａ４３は、置換基を有していてもよい炭素数１〜５の脂肪族炭化水素基又は単結合を表す。
Ｘ^ａ４１及びＸ^ａ４２は、それぞれ独立に、酸素原子、カルボニル基、カルボニルオキシ基又はオキシカルボニル基を表す。
ただし、Ａ^ａ４２、Ａ^ａ４３、Ａ^ａ４４、Ｘ^ａ４１及びＸ^ａ４２の炭素数の合計は６以下である。）
で表される基を表す。
Ｒ^ａ４２は、置換基を有していてもよい脂肪族炭化水素基を表す。該脂肪族炭化水素基は部分的に、炭素炭素不飽和結合を有していてもよいが、炭素炭素不飽和結合を有さない脂肪族飽和炭化水素基が好ましい。該脂肪族飽和炭化水素基としては、アルキル基（当該アルキル基は直鎖でも分岐していてもよい）及び脂環式炭化水素基、並びに、アルキル基及び脂環式炭化水素基を組み合わせた脂肪族炭化水素基などが挙げられる。］ A specific example of the acid stable structural unit (a4) is, for example, a structural unit represented by the following formula (a4-1) (hereinafter sometimes referred to as “structural unit (a4-1)”). As will be described later, this structural unit (a4-1) preferably has a fluorine atom.

[In the formula (a4-1),
R ^a41 represents a monovalent aliphatic hydrocarbon group having 1 to 12 carbon atoms or a monovalent aromatic hydrocarbon group having 6 to 12 carbon atoms, and a methylene group constituting the monovalent aliphatic hydrocarbon group. May be replaced by an oxygen atom or a carbonyl group. A ^a41 is an alkanediyl group having 1 to 6 carbon atoms which may have a substituent or a formula (a-g1).

(In the formula (a-g1),
s represents 0 or 1.
A ^a42 and A ^a44 each independently represent an aliphatic hydrocarbon group having 1 to 5 carbon atoms which may have a substituent.
A ^a43 represents a ^C1-C5 aliphatic hydrocarbon group which may have a substituent or a single bond.
X ^a41 and X ^a42 each independently represent an oxygen atom, a carbonyl group, a carbonyloxy group, or an oxycarbonyl group.
However, the total number of carbon atoms of A ^a42 , A ^a43 , A ^a44 , X ^a41 and X ^a42 is 6 or less. )
Represents a group represented by
R ^a42 represents an aliphatic hydrocarbon group which may have a substituent. The aliphatic hydrocarbon group may partially have a carbon-carbon unsaturated bond, but an aliphatic saturated hydrocarbon group having no carbon-carbon unsaturated bond is preferable. Examples of the aliphatic saturated hydrocarbon group include an alkyl group (the alkyl group may be linear or branched), an alicyclic hydrocarbon group, and an aliphatic combination of an alkyl group and an alicyclic hydrocarbon group. Group hydrocarbon group and the like. ]

^Among the aliphatic hydrocarbon groups for R ^a41 , the alkyl group and the aromatic hydrocarbon group include those already exemplified in the respective ranges of the carbon number.

［式（ａ−ｇ３）中、
Ｘ^ａ４３は、酸素原子、カルボニル基、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ^ａ４５は、ハロゲン原子を有していてもよい炭素数３〜１７の脂肪族炭化水素基を表す。］
つまり、Ｒ^ａ４２は、以下の式（ａ−ｇ２）で表される基であることが好ましい。

［式（ａ−ｇ２）中、
Ａ^ａ４６は、ハロゲン原子を有していてもよい炭素数３〜１７の脂肪族炭化水素基を表す。
Ｘ^ａ４４は、カルボニルオキシ基又はオキシカルボニル基を表す。
Ａ^ａ４７は、ハロゲン原子を有していてもよい炭素数３〜１７の脂肪族炭化水素基を表す。
ただし、Ａ^ａ４６、Ａ^ａ４７及びＸ^ａ４４の炭素数の合計は１８以下である。］ Further, the aliphatic hydrocarbon group R ^a42 may not have have a substituent, but when R ^a42 is an aliphatic hydrocarbon group having a substituent group. Such a substituent is preferably a halogen atom or a group represented by the formula (a-g3).

[In the formula (a-g3),
^Xa43 represents an oxygen atom, a carbonyl group, a carbonyloxy group or an oxycarbonyl group.
A ^a45 represents a ^C3-17 aliphatic hydrocarbon group which may have a halogen atom. ]
That is, R ^a42 is preferably a group represented by the following formula (a-g2).

[In the formula (a-g2),
A ^a46 represents an aliphatic hydrocarbon group having 3 to 17 carbon atoms which may have a halogen atom.
X ^a44 represents a carbonyloxy group or an oxycarbonyl group.
A ^a47 represents an aliphatic hydrocarbon group having 3 to 17 carbon atoms which may have a halogen atom.
However, the total number of carbon atoms of A ^a46 , A ^a47 and X ^a44 is 18 or less. ]

Preferred R ^a42 , an aliphatic hydrocarbon group having a substituent selected from the group consisting of a halogen atom and a group represented by formula (a-g3) (a group represented by formula (a-g2)) Detailed description.

  First, an aliphatic hydrocarbon group having a halogen atom will be described. Such an aliphatic hydrocarbon group is typically an alkyl group having a halogen atom and an alicyclic hydrocarbon group having a halogen atom (preferably a cycloalkyl group having a halogen atom). The alkyl group having a halogen atom is one in which part or all of the hydrogen atoms constituting the alkyl group are substituted with halogen atoms. Similarly, an alicyclic hydrocarbon group having a halogen atom is one in which part or all of the hydrogen atoms constituting the alicyclic hydrocarbon group are substituted with halogen atoms. The halogen atom contained in the alkyl group having a halogen atom and the alicyclic hydrocarbon group having a halogen atom is a fluorine atom, a chlorine atom, a bromine atom or an iodine atom, or a combination thereof, but a fluorine atom Is particularly preferred.

When the structural unit (a4-1) in which R ^a42 is an aliphatic hydrocarbon group having a fluorine atom is shown as a specific example when A ^a41 is a preferred ethylene group, the following formula (a4-1-1) To a structural unit represented by any one of formula (a4-1-22).

When R ^a42 is an aliphatic hydrocarbon group having a halogen atom, a perfluoroalkyl group in which all of the hydrogen atoms constituting the alkyl group are substituted with fluorine atoms, or all of the hydrogen atoms constituting the cycloalkyl group are fluorine atoms. A perfluorocycloalkyl group substituted with is more preferable. In the above specific examples, the structural unit (a4-1) in which R ^a42 is a perfluoroalkyl group or a perfluorocycloalkyl group includes the formula (a4-1-3), the formula (a4-1-4), and the formula (A4-1-7), Formula (a4-1-8), Formula (a4-1-11), Formula (a4-1-12), Formula (a4-1-15), Formula (a4-1-1-) 16), a structural unit represented by any one of formula (a4-1-19), formula (a4-1-20), formula (a4-1-21) and formula (a4-1-22) . Further, R ^a42 is preferably a perfluoroalkyl group, and ^examples of the perfluoroalkyl group include a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluorobutyl group, a perfluoropentyl group, a perfluorohexyl group, a perfluoroheptyl group, and a perfluorooctyl group. Is exemplified. More preferably, it is a C1-C6 perfluoroalkyl group, Most preferably, it is a C1-C3 perfluoroalkyl group.

Next, a case where R ^a42 is an aliphatic hydrocarbon group having a group represented by the formula (a-g3) will be described. The aliphatic hydrocarbon group may have one or a plurality of groups represented by the formula (a-g3), but the carbon atom contained in the group represented by the formula (a-g3) The total carbon number of the aliphatic hydrocarbon group including the number of is preferably 15 or less, and more preferably 12 or less. In order to satisfy such a preferable total carbon number, a group having one group represented by the formula (a-g3) is preferable as R ^a42 .

［式（ａ４−１’）中、すべての符号はいずれも、前記と同義である。］ The structural unit (a4-1) in which R ^a42 is an aliphatic hydrocarbon group having one group represented by the formula (a-g2) is specifically represented by the following formula (a4-1 ′). (Hereinafter, sometimes referred to as “structural unit (a4-1 ′)”).

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

In the monomer (a4-1 ′), both A ^a46 and A ^a47 may have a halogen atom, but A ^a46 is an aliphatic hydrocarbon group having a halogen atom, or A ^a47 is a halogen atom. The aliphatic hydrocarbon group having Furthermore, A ^a46 is preferably an aliphatic hydrocarbon group having a halogen atom, and among these, A ^a46 is more preferably an alkanediyl group having a fluorine atom, and particularly preferably a perfluoroalkanediyl group. The “perfluoroalkanediyl group” refers to an alkanediyl group in which all of the hydrogen atoms are substituted with fluorine atoms.

When the structural unit (a4-1 ′) in which A ^a46 is a perfluoroalkanediyl group is exemplified in the case where A ^a41 is an ethylene group, the following formula (a4-1′-1) to formula (a4-1′-) 22).

A ^a46 and ^Aa47 are arbitrarily selected in a range where the total number of carbon atoms is 17 or less, and the carbon number of ^Aa46 is preferably in the range of 1 to 6, more preferably in the range of 1 to 3.
On the other hand, the carbon number of ^Aa47 is preferably in the range of 4 to 15, and more preferably in the range of 5 to 12. Particularly preferred A ¹⁴ is an alicyclic hydrocarbon group having 6 to 12 carbon atoms, and the alicyclic hydrocarbon group is particularly preferably a cyclohexyl group or an adamantyl group.

このような構造を有する構造単位（ａ４−１’）は、前記の具体例の中では、式（ａ４−１’−９）〜式（ａ４−１’−２０）で表される構造単位が該当する。 Among the combinations of A ^a46 and ^{A a47,} the more ^preferable, * ^- is represented by the partial structure represented by ^{A a46} -X a44 ^{-A a47} (* represents a bond to a carbonyl group), the following structure Is mentioned.

The structural unit (a4-1 ′) having such a structure includes structural units represented by the formula (a4-1′-9) to the formula (a4-1′-20) in the above specific examples. Applicable.

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

  As described above, the structural unit (a1-1), the structural unit (a1-2), the other structural unit (a1), and the acid stable structural unit suitable as the structural unit (a1) of the resin (A). Although the acid stable structural unit (a2), the acid stable structural unit (a3), and the acid stable structural unit (a4) have been described in detail, the structural unit other than these may be included. Mention may be made of 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, and more preferably the structural unit. (A1-1) and / or monomer (a1) for deriving structural unit (a1-2) and acid-stable monomer for deriving acid-stable structural unit (a2) and / or acid-stable structural unit (a3) Polymerized. 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) and 50,000 or less (more preferably 30,000 or less). In addition, the weight average molecular weight here is calculated | required as a conversion value of a standard polystyrene reference | standard by gel permeation chromatography analysis. Detailed analysis conditions for this analysis are described in the Examples of the present application.

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

［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, the plurality of ^Rc4s 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 ^Rc9s 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のアルカンジイル基、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｓ−又はこれらを組合せた２価の基を表す。］

[In Formula (C5) and Formula (C6),
R ^c10 , R ^c11 , R ^c12 , R ^c13 and R ^c16 are each independently synonymous with R ^c1 .
R ^c14 , R ^c15 and R ^c17 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, the plurality of R ^c14 may be the same 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 C1-C6 alkanediyl 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のアルカンジイル基、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｓ−又はこれらを組合せた２価の基を表す。］

[In Formula (C7) and Formula (C8),
R ^{c18, R c19} and ^{R c20} in each occurrence independently ^{has the} same meaning as ^{R c4.}
q3, r3 and s3 each independently represent an integer of 0 to 3, and when q3 is 2 or more, the plurality of ^Rc18 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 ^Rc20s may be the same as or different from each other.
L ^c2 represents a single bond or an alkanediyl group having 1 to 6 carbon atoms, —CO—, —C (═NH) —, —S—, or a divalent group obtained by combining these. ]

  Examples of the compound represented by the formula (C1) include 1-naphthylamine, 2-naphthylamine, aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N- Dimethylaniline, diphenylamine, hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, tributylamine, tri Pentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyl Hexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctylamine, methyldinonylamine, methyldidecylamine, ethyldibutylamine, ethyldipentylamine, ethyldihexylamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonyl Amine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexamethylenediamine, 4,4′-diamino-1,2- Examples thereof include diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, and 4,4′-diamino-3,3′-diethyldiphenylmethane. Propyl aniline. Particularly preferred include 2,6-diisopropylaniline.

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

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

<Solvent (D)>
The present resist composition may contain a solvent (D). The solvent (D) has good applicability when the resist composition is applied on a substrate in the production of a resist pattern, which will be described later, according to the type and amount of the salt (I), the resin (A) and the like. From the point of view, it is possible to select the optimum one as appropriate.

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

<Other ingredients>
The resist composition comprises an acid generator containing a salt (I) and a resin (A), preferably an acid generator containing a salt (I), a resin (A), and a basic compound (C) used as necessary. ) And a solvent (D), but may contain components other than the basic compound (C) and the solvent (D) used as necessary. This component is referred to as “component (F)”. Such component (F) is an additive known in the art, and examples thereof include a sensitizer, a dissolution inhibitor, a surfactant, a stabilizer, and a dye.

<Preparation method of the present resist composition>
Then, the preparation method of this resist composition is demonstrated.
In the present resist composition, the salt (I) and the resin (A) and the solvent (D), the acid generator (B), the basic compound (C) and / or the component (F) used as necessary are mixed. Can be prepared. The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing should just select a suitable temperature range from the range of 10-40 degreeC according to the solubility with respect to solvent (D), such as resin (A) kind, resin (A), etc., and mixing time Is preferably 0.5 to 24 hours, depending on the mixing temperature. The mixing means is not particularly limited, and stirring and mixing can be used.

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

  The content of the salt (I) is preferably 10 parts by mass or more, more preferably 30 parts by mass or more with respect to 100 parts by mass of the total amount of the acid generator. In the present resist composition, substantially only the salt (I) can be used as an acid generator. As the acid generator other than the salt (I), the acid generator (B) is preferable.

  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.

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

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

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

  Thus, each of the acid generator containing the salt (I), the resin (A), and the basic compound (C), the solvent (D), or the component (F) used as necessary is mixed in a preferable content. Thereafter, the resist composition can be prepared by filtration using a filter having a pore size of about 0.003 to 0.2 μm.

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

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

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

Step (3) is a step of exposing the composition layer, and preferably the composition layer is exposed using an exposure machine. At this time, 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 emitting device 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 convert wavelength of laser light from a semiconductor laser or the like and emit harmonic laser light in the far ultraviolet region or the vacuum ultraviolet region can be used. The exposure machine may be an immersion exposure machine. The exposure machine may irradiate an electron beam or extreme ultraviolet light (EUV). In this specification, irradiating these radiations may be collectively referred to as “exposure”. When the exposure light source is an electron beam, a desired pattern may be directly drawn without using a photomask.

  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 salt (I) and the acid generator (B) contained in the composition layer generate an acid upon receiving exposure energy, and further, by the action with the generated acid, “insoluble in an alkaline aqueous solution”. Alternatively, the acid labile group in the resin (A) of the resin which is hardly soluble and becomes soluble in an alkaline aqueous solution by the action of an acid generates a hydrophilic group by a deprotection reaction. As a result, the composition layer of the exposed portion The resin (A) in (1) is soluble in an alkaline aqueous solution. On the other hand, since the exposure energy is not received in the unexposed area, the resin (A) remains insoluble or hardly soluble in the alkaline aqueous solution. Thus, since the composition layer in the exposed part and the composition layer in the unexposed part are remarkably different in solubility in the alkaline aqueous solution, a resist pattern can be formed by development with the alkaline aqueous solution.

  In the step (4), a heat treatment (so-called post-exposure baking) for further promoting the progress of the deprotecting group reaction that may occur in the exposed portion is performed. Such heat treatment is preferably the heating means using the hot plate shown in the step (2). In addition, when performing hot plate heating in a process (4), about 50-200 degreeC is preferable and the surface temperature of this hot plate has more preferable about 70-150 degreeC. The deprotection reaction is promoted by the heat treatment.

  Step (5) is a step of developing the heated composition layer using a developer, usually using a developing device. Examples of the developing method include a dipping method, a paddle method, a spray method, and a dynamic dispensing method. The development temperature is preferably 5 to 60 ° C., for example, and the development time is preferably 5 to 300 seconds, for example.

By selecting the type of developer, a positive resist pattern or a negative resist pattern can be produced.
When producing a positive resist pattern from the resist composition of the present invention, an alkaline developer is used as the developer. The alkaline developer may be various alkaline aqueous solutions used in this field. Examples thereof include an aqueous solution of tetramethylammonium hydroxide and (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline). The alkali developer may contain a surfactant.
It is preferable to wash the resist pattern with ultrapure water after development, and then remove the water remaining on the substrate and the pattern.

In the case of producing a negative resist pattern from the resist composition of the present invention, a developer containing an organic solvent as a developer (hereinafter sometimes referred to as “organic developer”) is used.
Organic solvents contained in the organic developer include ketone solvents such as 2-hexanone and 2-heptanone; glycol ether ester solvents such as propylene glycol monomethyl ether acetate; ester solvents such as butyl acetate; glycols such as propylene glycol monomethyl ether Examples include ether solvents; amide solvents such as N, N-dimethylacetamide; aromatic hydrocarbon solvents such as anisole.
In the organic developer, the content of the organic solvent is preferably 90% by mass or more and 100% by mass or less, more preferably 95% by mass or more and 100% by mass or less, and still more preferably only the organic solvent.
Among them, the organic developer is preferably a developer containing butyl acetate and / or 2-heptanone. In the organic developer, the total content of butyl acetate and 2-heptanone is preferably 50% by mass to 100% by mass, more preferably 90% by mass to 100% by mass, and substantially butyl acetate and / or 2 -More preferred is heptanone alone.
The organic developer may contain a surfactant. The organic developer may contain a trace amount of water.
At the time of development, the development may be stopped by substituting a solvent of a different type from the organic developer.

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

  According to the resist pattern manufacturing method including the steps (1) to (5) as described above, a resist pattern can be manufactured with excellent line edge roughness (LER) due to the effect of the present resist composition.

<Application>
This resist composition is suitable as a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) irradiation, or a resist composition for an EUV exposure machine. It can be used for fine processing of semiconductors.

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 obtained by gel permeation chromatography (HLC-8120GPC, manufactured by Tosoh Corporation, three columns are “TSKgel Multipore HXL-M”, and the solvent is tetrahydrofuran) using polystyrene as a standard product.
Column: TSKgel Multipore H _XL -M x 3 + guardcolumn (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μl
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)

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

式（Ｉ−３１−ａ）で表される塩１．５７部、クロロホルム３０部及びＮ−メチルピロリジン０．８５部を仕込み、０℃で３０分間攪拌した。その後、ここに、式（Ｉ−３１−ｂ）で表される化合物１．７４部を仕込み、０℃で３時間攪拌した。得られた反応物に、クロロホルム１５０部及び５％シュウ酸水溶液４０部を仕込み、攪拌、分液を行った。回収された有機層に、イオン交換水５０部を仕込み、攪拌、分液を行った。この水洗を５回行った。得られた有機層に活性炭１．００部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮し、酢酸エチル２０部を加えて攪拌した後、上澄液を除去した。残渣にｔｅｒｔ−ブチルメチルエーテル２０部を加えて攪拌した後、上澄液を除去した。残渣をクロロホルムに溶解した後、濃縮して、式（Ｉ−３１−ｃ）で表される塩１．４８部を得た。 Example 1: Synthesis of salt represented by formula (I-31)

1.57 parts of the salt represented by the formula (I-31-a), 30 parts of chloroform and 0.85 part of N-methylpyrrolidine were charged and stirred at 0 ° C. for 30 minutes. Thereafter, 1.74 parts of a compound represented by the formula (I-31-b) were charged therein and stirred at 0 ° C. for 3 hours. To the obtained reaction product, 150 parts of chloroform and 40 parts of a 5% oxalic acid aqueous solution were charged, stirred and separated. The recovered organic layer was charged with 50 parts of ion-exchanged water, and stirred and separated. This water washing was performed 5 times. The obtained organic layer was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated, 20 parts of ethyl acetate was added and stirred, and then the supernatant was removed. After adding 20 parts of tert-butyl methyl ether to the residue and stirring, the supernatant was removed. The residue was dissolved in chloroform and then concentrated to obtain 1.48 parts of the salt represented by the formula (I-31-c).

式（Ｉ−３１−ｄ）で表される化合物を特開２００６−２５７０７８号公報に記載された方法で合成した。式（Ｉ−３１−ｄ）で表される化合物１．８０部、クロロホルム２０部及びＮ−メチルピロリジン０．８５部を仕込み、０℃で３０分間攪拌した。その後、ここに、式（Ｉ−３１−ｂ）で表される化合物１．７４部を仕込み、０℃で３時間攪拌した。得られた反応物に、クロロホルム１００部及び５％シュウ酸水溶液４０部を仕込み、攪拌、分液を行った。回収された有機層に、イオン交換水５０部を仕込み、攪拌、分液を行った。この水洗を５回行った。得られた有機層に活性炭１．００部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮して、式（Ｉ−３１−ｅ）で表される化合物１．５４部を得た。

The compound represented by the formula (I-31-d) was synthesized by the method described in JP-A-2006-257078. 1.80 parts of a compound represented by the formula (I-31-d), 20 parts of chloroform and 0.85 part of N-methylpyrrolidine were charged and stirred at 0 ° C. for 30 minutes. Thereafter, 1.74 parts of a compound represented by the formula (I-31-b) were charged therein and stirred at 0 ° C. for 3 hours. The obtained reaction product was charged with 100 parts of chloroform and 40 parts of a 5% oxalic acid aqueous solution, and stirred and separated. The recovered organic layer was charged with 50 parts of ion-exchanged water, and stirred and separated. This water washing was performed 5 times. The obtained organic layer was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. The filtrate was concentrated to obtain 1.54 parts of a compound represented by the formula (I-31-e).

式（Ｉ−３１−ｅ）で表される化合物１．４１部に、アセトニトリル１０部及びイオン交換水１０部を加えた。さらに、式（Ｉ−３１−ｃ）で表される塩１．２８部、アセトニトリル５部及びイオン交換水５部を添加した。得られた混合物を１５時間撹拌した後、ろ過することにより式（Ｉ−３１）で表される塩１．０１部を得た。
ＭＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ４７５．１
ＭＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ５３５．１

10 parts of acetonitrile and 10 parts of ion-exchanged water were added to 1.41 parts of the compound represented by the formula (I-31-e). Further, 1.28 parts of the salt represented by the formula (I-31-c), 5 parts of acetonitrile and 5 parts of ion-exchanged water were added. The obtained mixture was stirred for 15 hours and then filtered to obtain 1.01 part of a salt represented by the formula (I-31).
MS (ESI (+) Spectrum): M ⁺ 475.1
MS (ESI (-) Spectrum): M ^- 535.1

式（Ｉ−４４−ｂ）で表される化合物０．５０部に、アセトニトリル１０部及びイオン交換水１０部を加えた。さらに、式（Ｉ−４４−ａ）で表される塩１．２８部、アセトニトリル５部及びイオン交換水５部を添加した。得られた混合物を１５時間撹拌した後、ろ過することにより式（Ｉ−４４−ｃ）で表される塩１．１８部を得た。 Example 2: Synthesis of salt represented by formula (I-44)

10 parts of acetonitrile and 10 parts of ion-exchanged water were added to 0.50 part of the compound represented by the formula (I-44-b). Further, 1.28 parts of the salt represented by the formula (I-44-a), 5 parts of acetonitrile and 5 parts of ion-exchanged water were added. The obtained mixture was stirred for 15 hours and then filtered to obtain 1.18 parts of the salt represented by the formula (I-44-c).

式（Ｉ−４４−ｃ）で表される塩１．００部及びアセトニトリル１０部を仕込み、４０℃で３０分間攪拌し、式（Ｉ−４４−ｄ）で表される化合物０．３０部を仕込み、５０℃で１時間攪拌することにより、式（Ｉ−４４−ｅ）で表される塩を含む溶液を得た。

1.00 parts of a salt represented by the formula (I-44-c) and 10 parts of acetonitrile are charged, stirred at 40 ° C. for 30 minutes, and 0.30 part of a compound represented by the formula (I-44-d) is added. The solution containing the salt represented by the formula (I-44-e) was obtained by charging and stirring at 50 ° C. for 1 hour.

得られた式（Ｉ−４４−ｅ）で表される塩を含む溶液に、式（Ｉ−４４−ｆ）で表される化合物０．３７部を仕込み、２３℃で１時間攪拌した。得られた反応マスに、クロロホルム１００部及びイオン交換水５０部を仕込み、攪拌、分液を行った。水洗を５回行った。得られた有機層に活性炭１．００部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮した後、得られた濃縮物に、アセトニトリル５０部を添加して溶解し、濃縮し、酢酸エチル５０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル５０部を加えて攪拌し、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮することにより、式（Ｉ−４４−ｇ）で表される塩１．０５部を得た。

To the obtained solution containing the salt represented by the formula (I-44-e), 0.37 part of the compound represented by the formula (I-44-f) was charged and stirred at 23 ° C. for 1 hour. To the obtained reaction mass, 100 parts of chloroform and 50 parts of ion-exchanged water were added, and the mixture was stirred and separated. Water washing was performed 5 times. The obtained organic layer was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. After concentrating the filtrate, 50 parts of acetonitrile was added to dissolve the resulting concentrate, the mixture was concentrated, 50 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 50 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 1.05 parts of the salt represented by the formula (I-44-g).

式（Ｉ−４４−ｇ）で表される塩１．００部、クロロホルム１０部並びに１Ｎ塩酸水溶液２．００部及びメタノール２．００部の混合溶液を仕込み、２３℃で１５時間撹拌した。その後、１Ｎ炭酸水素ナトリウム水溶液１０部を仕込み、攪拌後、分液した。回収された有機層に、イオン交換水１０部を仕込み、攪拌後、分液した。この水洗を３回行った。回収された有機層に活性炭１．００部を添加、攪拌後、濾過して濾液を回収し、該濾液を濃縮することにより、式（Ｉ−４４−ｈ）で表される塩０．７８部を得た。

A mixed solution of 1.00 parts of the salt represented by the formula (I-44-g), 10 parts of chloroform, 2.00 parts of 1N hydrochloric acid aqueous solution and 2.00 parts of methanol was charged and stirred at 23 ° C. for 15 hours. Thereafter, 10 parts of a 1N aqueous sodium hydrogen carbonate solution was added, and the mixture was stirred and separated. To the recovered organic layer, 10 parts of ion-exchanged water was added, and after stirring, the liquid was separated. This washing with water was performed three times. To the recovered organic layer, 1.00 part of activated carbon was added, stirred and then filtered to recover the filtrate, and the filtrate was concentrated to obtain 0.78 part of the salt represented by the formula (I-44-h). Got.

式（Ｉ−４４−ｈ）で表される塩０．６４部及びアセトニトリル１０部を仕込み、４０℃で３０分間攪拌し、式（Ｉ−４４−ｄ）で表される化合物０．１５部を仕込み、５０℃で１時間攪拌することにより、式（Ｉ−４４−ｉ）で表される塩を含む溶液を得た。

A salt represented by the formula (I-44-h) (0.64 parts) and acetonitrile (10 parts) were charged, stirred at 40 ° C. for 30 minutes, and 0.15 parts of the compound represented by the formula (I-44-d) The solution containing the salt represented by the formula (I-44-i) was obtained by charging and stirring at 50 ° C. for 1 hour.

得られた式（Ｉ−４４−ｉ）で表される塩を含む溶液に、式（Ｉ−４４−ｊ）で表される化合物０．１６部を仕込み、２３℃で１時間攪拌した。得られた反応マスに、クロロホルム５０部及びイオン交換水２０部を仕込み、攪拌、分液を行った。水洗を５回行った。得られた有機層に活性炭１．００部を仕込み、２３℃で３０分間攪拌し、ろ過した。ろ液を濃縮した後、得られた濃縮物に、アセトニトリル３０部を添加して溶解し、濃縮し、酢酸エチル３０部を加えて攪拌し、上澄液を除去した。得られた残渣にｔｅｒｔ−ブチルメチルエーテル３０部を加えて攪拌し、上澄液を除去した。得られた残渣をクロロホルムに溶解し、濃縮することにより、式（Ｉ−４４）で表される塩０．５８部を得た。
ＭＳ（ＥＳＩ（＋）Ｓｐｅｃｔｒｕｍ）：Ｍ^＋ ４７５．１
ＭＳ（ＥＳＩ（−）Ｓｐｅｃｔｒｕｍ）：Ｍ⁻ ５３５．１

To the obtained solution containing the salt represented by the formula (I-44-i), 0.16 part of the compound represented by the formula (I-44-j) was charged and stirred at 23 ° C. for 1 hour. To the obtained reaction mass, 50 parts of chloroform and 20 parts of ion-exchanged water were added, and the mixture was stirred and separated. Water washing was performed 5 times. The obtained organic layer was charged with 1.00 parts of activated carbon, stirred at 23 ° C. for 30 minutes, and filtered. After concentrating the filtrate, 30 parts of acetonitrile was added to the resulting concentrate to dissolve, concentrated, 30 parts of ethyl acetate was added and stirred, and the supernatant was removed. To the obtained residue, 30 parts of tert-butyl methyl ether was added and stirred, and the supernatant was removed. The obtained residue was dissolved in chloroform and concentrated to obtain 0.58 parts of the salt represented by the formula (I-44).
MS (ESI (+) Spectrum): M ⁺ 475.1
MS (ESI (-) Spectrum): M ^- 535.1

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

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

Synthesis Example 1 [Synthesis of Resin A1]
As the monomer, using monomer (a1-1-2), monomer (a1-2-3), monomer (a2-1-1), monomer (a3-2-3) and monomer (a3-1-1), The molar ratio (monomer (a1-1-2): monomer (a1-2-3): monomer (a2-1-1): monomer (a3-2-3): monomer (a3-1-1)) , 30: 14: 6: 20: 30, and 1.5 mass times dioxane of the total monomer amount was added to make a solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and these were heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The obtained resin was again dissolved in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 7.2. A copolymer A1 of × 10 ³ was obtained with a yield of 78%. This resin A1 has the following structural units.

Synthesis Example 2 [Synthesis of Resin A2]
As the monomer, using monomer (a1-1-2), monomer (a1-5-1), monomer (a2-1-1), monomer (a3-2-3) and monomer (a3-1-1), The molar ratio (monomer (a1-1-2): monomer (a1-5-1): monomer (a2-1-1): monomer (a3-2-3): monomer (a3-1-1))) , 30: 14: 6: 20: 30, and 1.5 mass times dioxane of the total monomer amount was added to make a solution. To this solution, 1 mol% and 3 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and these were heated at 75 ° C. for about 5 hours. did. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The obtained resin was again dissolved in dioxane, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin, followed by two reprecipitation operations of filtering the resin, and a weight average molecular weight of 7.2. A copolymer A2 of × 10 ³ was obtained with a yield of 78%. This resin A2 has the following structural units.

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

Synthesis Example 4 [Synthesis of Resin A4]
Monomer (a4-1-7) was used as a monomer, and 1.5 mass times dioxane of the total monomer amount was added to prepare a solution. Azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the solution in an amount of 0.7 mol% and 2.1 mol%, respectively, with respect to the total monomer amount, and these were added at 75 ° C. Heated for about 5 hours. The obtained reaction mixture was poured into a large amount of methanol / water mixed solvent to precipitate the resin, and this resin was filtered. The resin thus obtained was dissolved again in dioxane, and the solution obtained by pouring the solution into a methanol / water mixed solvent was precipitated twice, and the resin was filtered twice to perform the reprecipitation operation twice. 8 × 10 ⁴ resin A4 (copolymer) was obtained with a yield of 77%. This resin A4 has the following structural units.

Synthesis Example 5 [Synthesis of Resin A5]
As the monomer, using monomer (a1-1-3), monomer (a1-2-9), monomer (a2-1-3), monomer (a3-2-3) and monomer (a3-1-1), The molar ratio [monomer (a1-1-3): monomer (a1-2-9): monomer (a2-1-3): monomer (a3-2-3): monomer (a3-1-1)] It mixed so that it might become 45: 14: 2.5: 22: 16.5, and 1.5 mass times propylene glycol monomethyl ether acetate of the total monomer amount was added, and it was set as the solution. To this solution, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added in an amount of 0.95 mol% and 2.85 mol%, respectively, based on the total monomer amount, and these were added at 73 ° C. Heated for about 5 hours. The obtained reaction mixture was poured into a large amount of methanol / ion-exchanged water = 4/1 mixing solution to precipitate the resin, and the resin was filtered to obtain a resin A5 having a weight average molecular weight of 7.8 × 10 ³ (co-polymer). Polymer) with a yield of 73%. This resin A5 had the following structural units and was soluble in butyl acetate.

Examples 3 to 10, Comparative Example 1
<Preparation of resist composition>
As shown in Table 4, each component was mixed and dissolved, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

酸発生剤Ｉ−３１の５０ｍｇをジメチルスルホキサイド０．８０ｇに溶解し、２．３８質量％テトラメチルアンモニウムヒドロキシド水溶液０．２５ｇを添加し、１時間攪拌したあと、酸発生剤Ｉ−６２の分解物を確認したところ、開裂して以下の化合物が生成されていることを確認した。

<Acid generator>
I-31: salt represented by formula (I-31)

50 mg of the acid generator I-31 was dissolved in 0.80 g of dimethyl sulfoxide, 0.25 g of an aqueous 2.38 mass% tetramethylammonium hydroxide solution was added and stirred for 1 hour, and then the acid generator I-62. As a result, it was confirmed that the following compound was produced by cleavage.

酸発生剤Ｉ−４４の５０ｍｇをジメチルスルホキサイド０．８０ｇに溶解し、２．３８質量％テトラメチルアンモニウムヒドロキシド水溶液０．２５ｇを添加し、１時間攪拌したあと、酸発生剤Ｉ−４４の分解物を確認したところ、開裂して以下の化合物が生成されていることを確認した。

I-44: a salt represented by the formula (I-44)

50 mg of the acid generator I-44 was dissolved in 0.80 g of dimethyl sulfoxide, 0.25 g of an aqueous 2.38 mass% tetramethylammonium hydroxide solution was added, and the mixture was stirred for 1 hour, and then the acid generator I-44. As a result, it was confirmed that the following compound was produced by cleavage.

Acid generator B1-3:

Acid generator Z1:

<Resin>
A1: Resin A1
A2: Resin A2
A3: Resin A3
A4: Resin A4
<Basic compound: Quencher>
C1: 2,6-Diisopropylaniline

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

<Evaluation of alkaline aqueous solution development after immersion exposure of resist composition>
An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical Industries, Ltd.] was applied onto a 12-inch silicon wafer and baked at 205 ° C. for 60 seconds to obtain a thickness of 78 nm. An organic antireflection film was formed. Subsequently, the resist composition was spin-coated on the organic antireflection film so that the film thickness after drying (pre-baking) was 85 nm.
The obtained silicon wafer was pre-baked (PB) for 60 seconds on a direct hot plate at the temperature described in the “PB” column of Table 4. Using the ArF excimer stepper for immersion exposure [XT: 1900Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light] on the wafer on which the resist composition film is formed in this manner, the exposure amount is stepwise. The line and space pattern was subjected to immersion exposure. Note that ultrapure water was used as the immersion medium.
After the exposure, post-exposure baking (PEB) was performed for 60 seconds on a hot plate at the temperature described in the “PEB” column of Table 4, and then with an aqueous 2.38 mass% tetramethylammonium hydroxide solution for 60 seconds. Paddle development was performed to obtain a resist pattern.
In the obtained resist pattern, the exposure amount at which the 50 nm line and space pattern becomes an exposure amount of 1: 1 was defined as the effective sensitivity.

<Line edge roughness evaluation (LER)>
The wall surface of the resist pattern after the lithography process is observed with a scanning electron microscope.
What is 4.0 nm or less ○,
What exceeded 4.0 nm was set as x.
Table 5 shows the results of the line edge roughness evaluation (LER) obtained as described above. The numbers in parentheses indicate the touch width (nm) of the unevenness on the side wall.

<Development evaluation of organic solvent after immersion exposure of resist composition>
An organic antireflective coating composition [ARC-29; manufactured by Nissan Chemical Industries, Ltd.] was applied onto a 12-inch silicon wafer and baked at 205 ° C. for 60 seconds to obtain a thickness of 78 nm. An organic antireflection film was formed. Subsequently, the resist composition was spin-coated on the organic antireflection film so that the film thickness after drying (pre-baking) was 85 nm.
The obtained silicon wafer was pre-baked (PB) for 60 seconds on a direct hot plate at the temperature described in the “PB” column of Table 4. Using the ArF excimer stepper for immersion exposure [XT: 1900Gi; manufactured by ASML, NA = 1.35, 3/4 Annular XY polarized light] on the wafer on which the resist composition film is formed in this manner, the exposure amount is stepwise. The line and space pattern was subjected to immersion exposure. Note that ultrapure water was used as the immersion medium.
After exposure, on the hot plate, post exposure bake (PEB) is performed for 60 seconds at the temperature described in the “PEB” column of Table 4, and then paddle development is performed with butyl acetate for 30 seconds to obtain a resist pattern. It was.
In the obtained resist pattern, the exposure amount at which the 50 nm line and space pattern becomes an exposure amount of 1: 1 was defined as the effective sensitivity.

<Line edge roughness evaluation (LER)>
The wall surface of the resist pattern after the lithography process is observed with a scanning electron microscope.
What is 4.0 nm or less ○,
What exceeded 4.0 nm was set as x.
Table 6 shows the results of the line edge roughness evaluation (LER) obtained as described above. The numbers in parentheses indicate the touch width (nm) of the unevenness on the side wall.

  If a resist composition containing the salt of the present invention as an acid generator is used, a resist pattern can be produced with excellent line edge roughness (LER).

Claims (9)

A salt comprising an anion having a group that is cleaved by the action of an alkali developer and a cation having a group that is cleaved by the action of an alkali developer ,
An anion having a group that is cleaved by the action of an alkali developer is an anion represented by the formula (IAa) or an anion represented by the formula (IAb);

[In the formulas (IAa) and (IAb),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ¹ is a group represented by the formula (b1-1),

[In Formula (b1-1), L ^b2 represents a single bond or an alkanediyl group having 1 to 15 carbon atoms. * Represents a bond with a carbon atom of C (Q ¹ ) (Q ² ). ]
Y is any of the alicyclic hydrocarbon groups represented by the following [* represents a bond. ],

R ³ and R ⁴ each independently represents a C 1-6 alkyl group having a fluorine atom.
R ⁵ and R ⁶ each independently represents a hydrogen atom or a fluorine atom. ]
A cation having a group that is cleaved by the action of an alkali developer is a triarylsulfonium cation (provided that one of the three aryl groups constituting the cation is one group that is cleaved by the action of an alkali developer. And)
The group which is cleaved by the action of an alkali developer contained in the cation is a salt represented by the group represented by formula (Ba) or the group represented by formula (Bb).

[In Formula (Ba), R ³ represents a C 1-6 alkyl group having a fluorine atom.
* Represents a bond. ]

[In formula (Bb), R ⁴ represents a C 1-6 alkyl group having a fluorine atom.
R ⁵ and R ⁶ each independently represents a hydrogen atom or a fluorine atom.
* Represents a bond. ] The salt according to claim 1, wherein the anion having a group that is cleaved by the action of an alkali developer is an anion represented by any one of the following formulae .

[Wherein R ^{3 to} R ⁶ each have the same meaning as described above. ] The salt according to claim 1 or 2 , wherein the anion having a group that is cleaved by the action of an alkali developer is an anion represented by any one of the following formulae .

The salt according to any one of claims 1 to 3, wherein the cation having a group that is cleaved by the action of an alkali developer is a group represented by the following formula .

An anion having a group that is cleaved by the action of an alkali developer is an anion represented by any of the following formulae:

The salt according to claim 1 or 2 , wherein the cation having a group that is cleaved by the action of an alkali developer is a group represented by the following formula .

  The acid generator which contains the salt in any one of Claims 1-5 as an active ingredient.   The acid generator according to claim 6 and a resin, wherein the resin has an acid labile group and is insoluble or hardly soluble in an alkaline aqueous solution, and can be dissolved in an alkaline aqueous solution by acting with an acid. Resist composition which is resin.   The resist composition according to claim 7, further comprising a basic compound. (1) The process of apply | coating the resist composition of Claim 7 or 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.