JP2013006827A - Salt, resist composition and method for producing resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide production of a resist pattern having more superior line width roughness (LWR) based on the more miniaturization of design dimension of semiconductor microfabrication.SOLUTION: There are provided a salt having each one of a tertiary sulfur atom and a carboxylate group in the molecule, a resist composition containing the salt, and a production method for resist patterns, using the resist composition. As the salt, a salt represented by formula (I) is preferable. [In formula (I), Aand Aare each independently a 1-18C univalent organic group; Ais a 1-18C bivalent organic group; and Aand Amay be bonded to each other to form a heterocycle with a sulfur atom bonded therewith, and Aand Amay be bonded to each other to form a heterocycle with a sulfur atom bonded therewith].

Description

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

  Resist compositions for ArF exposure (hereinafter sometimes referred to as “resist compositions”) that are actively being developed for semiconductor microfabrication are insoluble or hardly soluble in an aqueous alkali solution, A resin that can be dissolved in an aqueous solution and an acid generator are contained. In addition to the resin and the acid generator, the resist composition may contain additives such as a basic compound in order to adjust the characteristics. Such basic compounds are referred to in the art as “quenchers”.

As such a resist composition, Patent Document 1 discloses:
A resin obtained from methacrylic acid = 2-isopropyl-2-adamantyl, 3-hydroxy-1-adamantyl methacrylate, methacrylic acid = 1-ethyl-1-cyclohexyl, and α-methacryloyloxy-γ-butyrolactone; 4-methylphenyl) sulfonium 1-((3-hydroxyadamantyl) methoxycarbonyl) difluoromethanesulfonate acid generator;
A resist composition comprising a quencher comprising 2,6-diisopropylaniline is described.

JP 2010-152341 A

  As the design dimensions of semiconductor microfabrication continue to become finer, there is a demand for the production of resist patterns having better line width roughness (LWR). In order to produce such a resist pattern, the resist composition described in Patent Document 1 still has room for improvement.

［式（Ｉ）中、
Ａ^１及びＡ^２は、それぞれ独立に炭素数１〜１８の１価の有機基であり、
Ａ^３は炭素数１〜１８の２価の有機基である。Ａ^１及びＡ^２が互いに結合して、これらが結合している硫黄原子とともに複素環を形成していてもよく、Ａ^１及びＡ^３が互いに結合して、これらが結合している硫黄原子とともに複素環を形成していてもよい。］
〔３〕前記式（Ｉ）のＡ^１及びＡ^２が、それぞれ独立に、以下の置換基群Ｐ１から選ばれる基を有していてもよい１価の脂肪族炭化水素基、又は、以下の置換基群Ｐ２から選ばれる基を有していてもよい１価の芳香族炭化水素基である、前記〔２〕記載の塩。
〔置換基群Ｐ１〕
ヒドロキシ基及び炭素数６〜１２のアリール基
〔置換基群Ｐ２〕
ヒドロキシ基、炭素数１〜６のアルキル基及び炭素数１〜６のアルコキシ基
〔４〕前記式（Ｉ）のＡ^１及びＡ^２が、それぞれ独立に、炭素数１〜６のアルキル基である、前記〔２〕記載の塩。
〔５〕前記式（Ｉ）のＡ^３が、芳香環を含む２価の有機基である、前記〔２〕記載の塩。
〔６〕前記式（Ｉ）のＡ^３が、２価の芳香族炭化水素基である、前記〔２〕記載の塩。
〔７〕レジスト組成物用添加剤として用いられる、前記〔１〕〜〔６〕のいずれか記載の塩。
〔８〕前記〔１〕〜〔７〕のいずれか記載の塩と、
アルカリ水溶液に不溶又は難溶であり、酸の作用によりアルカリ水溶液に溶解し得る樹脂と、
酸発生剤と
を含有するレジスト組成物。
〔９〕（１）請求項８記載のレジスト組成物を基板上に塗布する工程、
（２）塗布後の組成物を乾燥させて組成物層を形成する工程、
（３）組成物層を露光する工程、
（４）露光後の組成物層を加熱する工程、及び
（５）加熱後の組成物層を現像する工程、
を含むレジストパターンの製造方法。 The present invention includes the following inventions.
[1] A salt having one tertiary sulfur atom and one carboxylate group in the molecule.
[2] The salt according to [1], which is represented by the formula (I).

[In the formula (I),
A ¹ and A ² are each independently a monovalent organic group having 1 to 18 carbon atoms,
A ³ is a divalent organic group having 1 to 18 carbon atoms. A ¹ and A ² may be bonded to each other to form a heterocyclic ring together with the sulfur atom to which they are bonded, and A ¹ and A ³ are bonded to each other, together with the sulfur atom to which they are bonded A heterocycle may be formed. ]
[3] A ¹ and A ^{2 in} the formula (I) each independently represent a monovalent aliphatic hydrocarbon group which may have a group selected from the following substituent group P1, or The salt according to [2] above, which is a monovalent aromatic hydrocarbon group which may have a group selected from substituent group P2.
[Substituent group P1]
Hydroxy group and aryl group having 6 to 12 carbon atoms [Substituent group P2]
Hydroxy group, alkyl group having 1 to 6 carbon atoms, and alkoxy group having 1 to 6 carbon atoms [4] A ¹ and A ^{2 in} formula (I) are each independently an alkyl group having 1 to 6 carbon atoms. The salt of [2] above.
[5] The salt according to [2], wherein A ^{3 in the} formula (I) is a divalent organic group containing an aromatic ring.
[6] The salt according to [2], wherein A ^{3 in the} formula (I) is a divalent aromatic hydrocarbon group.
[7] The salt according to any one of [1] to [6], which is used as an additive for a resist composition.
[8] The salt according to any one of [1] to [7],
A resin that is insoluble or hardly soluble in an aqueous alkaline solution and that can be dissolved in an aqueous alkaline solution by the action of an acid;
A resist composition containing an acid generator.
[9] (1) A step of applying the resist composition according to claim 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 step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including:

  If the resist composition containing the salt of the present invention is used, a resist pattern having excellent line width roughness (LWR) can be produced.

The present invention
A salt having a specific atom and a specific group in the molecule;
The salt, a resin that is insoluble or hardly soluble in an alkaline aqueous solution and can be dissolved in an alkaline aqueous solution by the action of an acid (hereinafter sometimes referred to as “resin (A)”), and an acid generator (hereinafter sometimes referred to as “ A resist composition (hereinafter referred to as “the present resist composition”);
A method for producing a resist pattern using the present resist composition is provided.
First, such a salt will be described with a focus on suitable ones, and components of the resist composition other than the salt and a method for preparing the resist composition using these components will be described. Finally, a method for producing a resist pattern using the present resist composition will be described.

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

  In this specification, an organic group means a group containing a carbon atom, and includes a hydrocarbon group and a group in which a hetero atom such as an oxygen atom, a nitrogen atom, or a halogen atom is contained in part of the hydrocarbon group. .

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.
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 ), a heptyl group ( C ₇ ), octyl group (C ₈ ), decyl group (C ₁₀ ), dodecyl group (C ₁₂ ), hexadecyl group (C ₁₄ ), pentadecyl group (C ₁₅ ), hexyldecyl group (C ₁₆ ), heptadecyl group ( C ₁₇ ) and octadecyl group (C ₁₈ ).
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.
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, and 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, methylidene group, ethylidene group, propylidene group, 2-propylidene group, 1-methyl-1,3-propylene group, 2-methyl-1,3-propylene group, 2- Chill-1,2-propylene group, a 1-methyl-1,4-butylene group and 2-methyl-1,4-butylene group.

  The cyclic aliphatic hydrocarbon group (hereinafter sometimes referred to as “alicyclic hydrocarbon group”) typically means a cycloalkyl group, and is any of the monocyclic and polycyclic groups shown below. 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-19) 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-19).

The aliphatic hydrocarbon group may have a substituent. Such a substituent is defined each time, and examples of the substituent 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, acetyl group (C ₂ ), propionyl group (C ₃ ), butyryl group (C ₄ ), valeryl group (C ₅ ), hexylcarbonyl group (C ₆ ), heptylcarbonyl group (C ₇ ), octyl An alkyl group such as a carbonyl group (C ₈ ), a decylcarbonyl group (C ₁₀ ) and a dodecylcarbonyl group (C ₁₂ ) and a carbonyl group, and an aryl group such as a benzoyl group (C ₇ ) and a carbonyl group Combined are included.
Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, and an isobutyryloxy group.
Examples of the aralkyl group include benzyl group (C ₇ ), phenethyl group (C ₈ ), phenylpropyl group (C ₉ ), naphthylmethyl group (C ₁₁ ), and naphthylethyl group (C ₁₂ ).
The aryloxy group includes phenyloxy group (C ₆ ), naphthyloxy group (C ₁₀ ), antonyloxy group (C ₁₄ ), biphenyloxy group (C ₁₂ ), phenanthryloxy group (C ₁₄ ) and full A combination of an aryl group such as an oleenyloxy group (C ₁₃ ) and an oxygen atom is exemplified.

A 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 antonyl group (C ₁₄ ), a biphenyl group (C ₁₂ ), a phenanthryl group (C ₁₄ ), and a fluorenyl group (C ₁₃ ). . An arylene group obtained by further removing one hydrogen atom from the aryl group shown here corresponds to a divalent aromatic hydrocarbon group.

  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.

<Salt>
The salt of the present invention has one tertiary sulfur atom and one carboxylate group in its molecule. The tertiary sulfur atom refers to a sulfur atom (-S ⁺ =) having a positive charge by bonding three groups. The carboxylate group is a group formed by dissociating a hydrogen ion from a carboxyl group, represented by * —COO ⁻ (* is a bond), and has a negative charge. The salt of the present invention is electrically neutralized by the positive charge of the tertiary sulfur atom and the negative charge of the carboxylate group. When such a salt of the present invention is used as an additive for a resist composition to be described later, a resist composition capable of producing a resist pattern having excellent line width roughness (LWR) can be obtained. The salt of the present invention that can realize such a resist composition is useful and novel, and has been obtained by the inventors' original knowledge.

［式（Ｉ）中、
Ａ^１及びＡ^２は、それぞれ独立に炭素数１〜１８の１価の有機基であり、
Ａ^３は炭素数１〜１８の２価の有機基である。Ａ^１及びＡ^２が互いに結合して、これらが結合している硫黄原子とともに複素環を形成していてもよく、Ａ^１及びＡ^３が互いに結合して、これらが結合している硫黄原子とともに複素環を形成していてもよい。］ The salt of the present invention is preferably represented by the formula (I). Such salts are hereinafter sometimes referred to as “salts (I)”.

[In the formula (I),
A ¹ and A ² are each independently a monovalent organic group having 1 to 18 carbon atoms,
A ³ is a divalent organic group having 1 to 18 carbon atoms. A ¹ and A ² may be bonded to each other to form a heterocyclic ring together with the sulfur atom to which they are bonded, and A ¹ and A ³ are bonded to each other, together with the sulfur atom to which they are bonded A heterocycle may be formed. ]

The organic group of A ¹ and A ² may be any of an aliphatic hydrocarbon group, an aromatic hydrocarbon group, and a combination of an aliphatic hydrocarbon group and an aromatic hydrocarbon group. Moreover, as long as it is a range of 18 or less carbon atoms, a part thereof may contain a hetero atom, but the organic group of A ¹ and A ² includes a tertiary sulfur atom and a carboxylate group. Absent. Specific examples of the aliphatic hydrocarbon group and the aromatic hydrocarbon group include those already exemplified in the range of 18 or less carbon atoms. Moreover, the combination of an aliphatic hydrocarbon group and an aromatic hydrocarbon group can also be arbitrarily combined if it is the range of 18 or less carbon atoms. The organic groups of A ¹ and A ² are each independently selected from a monovalent aliphatic hydrocarbon group which may have a substituent selected from the substituent group P1, or the following substituent group P2. A monovalent aromatic hydrocarbon group which may have a substituent is preferable.
[Substituent group P1]
Hydroxy group and aryl group having 6 to 12 carbon atoms [Substituent group P2]
Hydroxy group, alkyl group having 1 to 6 carbon atoms, and alkoxy group having 1 to 6 carbon atoms

Here, a monovalent aliphatic hydrocarbon group that may have a group selected from the substituent group P1, and a monovalent aromatic hydrocarbon group that may have a group selected from the substituent group P2. Preferable examples are given for the group.
Preferred examples of the monovalent aliphatic hydrocarbon group which may have a group selected from the substituent group P1 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. Alkyl groups such as a group, nonyl group, decyl group, undecyl group and dodecyl group; cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, norbornyl group, 1- Cycloalkyl groups such as adamantyl group, 2-adamantyl group and isobornyl group; arylalkyl groups such as benzyl group and naphthylmethyl group; hydroxymethyl group, hydroxyethyl group, hydroxypropyl group, hydroxybutyl group, hydroxypentyl group, hydroxyhexyl Group, heptyl group and hydride And the like hydroxyalkyl groups such Kishiokuchiru group.

  Preferred examples of the monovalent aromatic hydrocarbon group that may have a group selected from the substituent group P2 include aryl groups such as a phenyl group, a naphthyl group, an anthranyl group, a biphenyl group, an anthryl group, and a phenanthryl group; alkylaryl groups such as p-methylphenyl, p-butylphenyl, tolyl, xylyl, cumenyl, mesityl, 2,6-diethylphenyl and 2-methyl-6-ethylphenyl; phenoxy and hydroxy Hydroxyaryl groups such as naphthyl group; alkoxyaryl groups such as methoxyphenyl group, ethoxyphenyl group, dimethoxyphenyl group, methoxynaphthyl group, ethoxynaphthyl group and dimethoxynaphthyl group.

で示される部分構造が、以下のいずれかの構造となった場合を挙げることができる。

これらの式においては、
Ｒ^ｓ１、Ｒ^ｓ２、Ｒ^ｓ３及びＲ^ｓ４は、それぞれ独立に、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炭素数３〜１２の脂環式炭化水素基を表す。また、ｔ１は、０〜４の整数、ｔ２は、０〜５の整数、ｔ３は、０〜８の整数、ｔ４は、０〜８の整数をそれぞれ表す。なお、ここでいうアルキル基、アルコキシ基及び脂環式炭化水素基の具体例は、炭素数が各々の範囲において、すでに例示したものを含む。また、これらのうちの

は、環を構成するメチレン基の１つ乃至２つが、酸素原子又はカルボニル基に置き換わっていてもよい。 Specific examples in which A ¹ and A ² are bonded to each other to form a heterocyclic ring with the sulfur atom to which they are bonded are included in the salt (I).

The case where the partial structure shown by any one of the following structures can be mentioned.

In these equations,
R ^s1 , R ^s2 , R ^s3 and R ^s4 are each independently a hydroxy group, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group having 3 to 12 carbon atoms. Represents. T1 represents an integer of 0 to 4, t2 represents an integer of 0 to 5, t3 represents an integer of 0 to 8, and t4 represents an integer of 0 to 8, respectively. In addition, the specific example of an alkyl group, an alkoxy group, and an alicyclic hydrocarbon group here contains what was already illustrated in carbon number in each range. Also of these

In the ring, one or two of the methylene groups constituting the ring may be replaced with an oxygen atom or a carbonyl group.

As described above, specific examples of the heterocyclic ring formed by bonding A ¹ and A ² to each other have been shown. The heterocyclic ring preferably has 4 to 6 carbon atoms.

Although the organic group of A ¹ and A ^2, has been described with reference to specific examples and preferred examples among these, organic groups of A ¹ and A ² are each independently alkyl having 1 to 10 carbon atoms Group, a phenyl group or a naphthyl group, and more preferably an alkyl group having 1 to 6 carbon atoms. The salt (I) in which A ¹ and A ² are each independently an alkyl group having 1 to 10 carbon atoms, a phenyl group, or a naphthyl group, particularly a salt (I) that is an alkyl group having 1 to 6 carbon atoms, is described later. This manufacturing method has an advantage that it can be easily manufactured.

The organic group for A ³ may be any of a divalent aliphatic hydrocarbon group, a divalent aromatic hydrocarbon group, and a divalent group of a combination of an aliphatic hydrocarbon group and an aromatic hydrocarbon group. Moreover, if it is the range of 18 or less carbon atoms, a hetero atom may be included in a part thereof, but the tertiary sulfur atom and the carboxylate group are not included in the organic group of A ³ . Specific examples of the divalent aliphatic hydrocarbon group and the divalent aromatic hydrocarbon group include those already exemplified in the range of 18 or less carbon atoms. In addition, a divalent group of a combination of an aliphatic hydrocarbon group and an aromatic hydrocarbon group can be arbitrarily combined as long as it has a carbon number of 18 or less.

Examples of the organic group for A ³ include an alkanediyl group, an alicyclic hydrocarbon group, an arylene group, or a divalent group in which these are arbitrarily combined. Specific examples of the alkanediyl group, alicyclic hydrocarbon group, and arylene group mentioned here include those already exemplified in the respective ranges of the carbon number. Moreover, the divalent group which combined the alkanediyl group and alicyclic hydrocarbon group here, and the alkanediyl group and alicyclic hydrocarbon group is 1 thru | or three of the methylene groups which comprise this group. , Oxygen atom or carbonyl group may be substituted.

式（Ｘ^１−Ａ）〜式（Ｘ^１−Ｃ）中において、
Ｘ^１Ａ及びＸ^１Ｂは、それぞれ独立に、炭素数１〜６のアルカンジイル基を表す。式（Ｘ^１−Ａ）〜式（Ｘ^１−Ｃ）で表される基の総炭素数の上限は１７である。このＸ^１Ａ及びＸ^１Ｂのアルカンジイル基を構成するメチレン基も、酸素原子又はカルボニル基に置き換わることもある。 Examples of the organic group in which the alkanediyl group and the alicyclic hydrocarbon group are combined include groups represented by any of the formulas (X ¹ -A) to (X ¹ -C).

In the formula (X ¹ -A) to the formula (X ¹ -C),
X ^1A and X ^1B each independently represent an alkanediyl group having 1 to 6 carbon atoms. The upper limit of the total carbon number of the groups represented by the formula (X ¹ -A) to the formula (X ¹ -C) is 17. The methylene group constituting the alkanediyl group of X ^1A and X ^1B may also be replaced with an oxygen atom or a carbonyl group.

Here, specific examples of groups in which one to three methylene groups constituting the alkanediyl group are replaced with oxygen atoms or carbonyl groups will be given. For example, as a group in which an methylene group constituting an alkanediyl group is replaced with an oxygen atom, * —X ⁷ —O—X ⁸ — * (wherein one of two * is a bond to a carboxylate group) And the other is a bond with a tertiary sulfur atom). Here, X ⁷ and X ⁸ represent a single bond or an alkanediyl group having 1 to 15 carbon atoms, and the upper limit of the total carbon number of X ⁷ and X ⁸ is 17. In addition, the specific example of an alkanediyl group here includes what was already illustrated in the range of C1-C15.

More specifically, examples of groups in which one to three methylene groups constituting an alkanediyl group and an organic group of a combination of an alkanediyl group and a cycloalkanediyl group are replaced with an oxygen atom or a carbonyl group are given. It is as follows.

The case where A ³ is an alkanediyl group, an alicyclic hydrocarbon group, or a combination of an alkanediyl group and an alicyclic hydrocarbon group has been described above. A ³ is a divalent aromatic hydrocarbon. A divalent organic group containing a group or an aromatic ring is preferred. When A ³ is an aromatic hydrocarbon group, it is typically an arylene group, and specific examples of the arylene group include those already exemplified in the range of 18 or less carbon atoms. Incidentally, the group containing an aromatic ring, ^{typically, * - X 10 -Ar-X} 11 - * ( provided, however, that the two *, one is bond to the carboxylate group, the other 3 A bond with a secondary sulfur atom). Here, X ¹⁰ and X ¹¹ each independently represent a single bond or an alkanediyl group, and neither of them is a single bond. Ar represents a divalent aromatic hydrocarbon group. Then, ^Ar, the upper limit of the total number of carbon atoms of ^{X 10} and ^{X 11} is 18.

Of the groups containing an aromatic hydrocarbon group and an aromatic ring, an aromatic hydrocarbon group, particularly an arylene group, is preferable as A ³ . More preferably, the arylene group has 12 or less carbon atoms.

As described above, A ¹ , A ^2, and A ³ constituting the salt (I) have been described with specific examples. However, these are prepared using raw materials that are easily available from the market, for example, by the production method of the salt (I) described later. It is also possible to select from the points that can be easily manufactured. In view of the easily prepared salt (I), A ¹ and A ² are preferably a monovalent aliphatic hydrocarbon group, and more preferably an alkyl group having 1 to 6 carbon atoms as described above. As described above, A ³ is preferably an arylene group, and more preferably a phenylene group.

Specific examples of the salt (I) are shown below.

上式中、
Ａ^１、Ａ^２及びＡ^３はそれぞれ上記と同じ意味である。Ｘ^ｈａlは脱離基を表し、典型的にはハロゲン原子である。
この反応により、式（Ｉ−Ａ）で表される化合物と、式（Ｉ−Ｂ）で表される化合物とを反応させることにより塩（Ｉ）は製造できる。かかる反応は、酸化銀又は過塩素酸銀の存在下、有機溶媒中で実施できる。該有機溶媒としてはクロロホルム、ジクロロメタン、ジクロロエタン、メタノール、ジメチルホルムアミド及びアセトニトリルなどが用いられる。 Then, the manufacturing method of salt (I) is demonstrated. For example, the salt (I) is prepared by preparing a compound having a sulfide bond and a carboxyl group in the molecule, and tertiaryizing a sulfur atom (secondary sulfur atom) forming a sulfide bond in the compound to form a tertiary compound. It can be produced by using sulfur atoms. Such a production method is shown in the form of a reaction formula as follows.

In the above formula,
A ¹ , A ² and A ³ each have the same meaning as described above. X ^hal represents a leaving group, and is typically a halogen atom.
By this reaction, the salt (I) can be produced by reacting the compound represented by the formula (IA) with the compound represented by the formula (IB). Such a reaction can be carried out in an organic solvent in the presence of silver oxide or silver perchlorate. As the organic solvent, chloroform, dichloromethane, dichloroethane, methanol, dimethylformamide, acetonitrile and the like are used.

<This resist composition>
By containing the salt (I), the present resist composition makes it possible to produce a resist pattern having excellent line width roughness (LWR). The resist composition contains a resin (A) and an acid generator (B) in addition to the salt (I). Furthermore, it is preferable to contain a solvent (hereinafter sometimes referred to as “solvent (D)”). Further, the resist composition may contain a basic compound (hereinafter, “basic compound (C)” in some cases), which is a quencher well known in the art, as necessary. Hereinafter, the constituent components of the resist composition other than the salt (I) will be described in the order of the acid generator (B) and the resin (A), and the basic compound (C) and the solvent (D) as optional components. .

<Acid generator (B)>
The acid generator (B) contained in the resist composition is preferably one that generates sulfonic acid, but is not limited thereto, and even if it is a nonionic acid generator, it is an ionic acid generator. Or a combination thereof. Nonionic acid generators include organic halides, sulfonate esters (for example, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, N-sulfonyloxyimide, sulfonyloxyketone, DNQ 4− Sulfonate) and sulfones (for example, disulfone, ketosulfone, sulfonyldiazomethane) and the like. Examples of the ionic acid generator include onium salts containing onium cations (for example, diazonium salts, phosphonium salts, sulfonium salts, iodonium salts) and the like. Examples of the anion of the onium salt include a sulfonate anion, a sulfonylimide anion, and a sulfonylmethide anion.

  Examples of the acid generator (B) include JP-A 63-26653, JP-A 55-164824, JP-A 62-69263, JP-A 63-146038, JP-A 63-163452, JP 62-153853, JP 63-146029, U.S. Pat. No. 3,779,778, U.S. Pat.No. 3,849,137, German Patent 3914407 and European Patent 126,712. Compounds that generate an acid by radiation described in the above can also be used.

［式（Ｂ１）中、
Ｑ¹及びＱ²は、それぞれ独立に、フッ素原子又は炭素数１〜６のペルフルオロアルキル基を表す。
Ｌ^b1は、単結合又は炭素数１〜１７の２価の脂肪族飽和炭化水素基を表し、該２価の脂肪族飽和炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。
Ｙは、置換基を有していてもよい炭素数１〜１８の１価の脂肪族炭化水素基を表し、該１価の脂肪族炭化水素基を構成するメチレン基は、酸素原子、スルホニル基又はカルボニル基に置き換わっていてもよい。
Ｚ⁺は、有機カチオンを表す。］ Among these, an acid generator that generates a suitable sulfonic acid will be described. Among the acid generators that generate sulfonic acid, more preferred are fluorine-containing acid generators, and more preferred are sulfonates represented by formula (B1) (hereinafter sometimes referred to as “acid generator (B1)”. It is said.)

[In the formula (B1),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a single bond or a divalent aliphatic saturated hydrocarbon group having 1 to 17 carbon atoms, and the methylene group constituting the divalent aliphatic saturated hydrocarbon group is replaced with an oxygen atom or a carbonyl group. May be.
Y represents a monovalent aliphatic hydrocarbon group having 1 to 18 carbon atoms which may have a substituent, and the methylene group constituting the monovalent aliphatic hydrocarbon group includes an oxygen atom, a sulfonyl group Alternatively, it may be replaced with a carbonyl group.
Z ⁺ represents an organic cation. ]

Specific examples of the perfluoroalkyl group of Q ¹ and Q ² are those in which all of the hydrogen atoms constituting the alkyl group are replaced with fluorine atoms in the alkyl group having 1 to 6 carbon atoms among the already exemplified alkyl groups. Applicable. Specifically, for example, a perfluoromethyl group, a perfluoroethyl group, a perfluoropropyl group, a perfluoroisopropyl group, a perfluorobutyl group, a perfluorosec-butyl group, a perfluorotert-butyl group, a perfluoropentyl group, a perfluorohexyl group, etc. It is done.
As the acid generator (B1) contained in the resist composition, Q ¹ and Q ² are each independently preferably a trifluoromethyl group or a fluorine atom acid generator (B1). Q ¹ and Q ² An acid generator (B1) in which both are fluorine atoms is more preferred.

Specific examples of the aliphatic hydrocarbon group represented by L ^b1 include the removal of two hydrogen atoms from the alkanediyl group exemplified above and the alicyclic hydrocarbons of the above formulas (KA-1) to (KA-19). Group.

式（ｂ１−１）〜式（ｂ１−６）中、
Ｌ^b2は、単結合又は炭素数１〜１５の脂肪族炭化水素基を表し、この脂肪族炭化水素基は脂肪族飽和炭化水素基が好ましい。
Ｌ^b3は、単結合又は炭素数１〜１２の脂肪族炭化水素基を表し、この脂肪族炭化水素基は脂肪族飽和炭化水素基が好ましい。
Ｌ^b4は、炭素数１〜１３の脂肪族炭化水素基を表し、この脂肪族炭化水素基は脂肪族飽和炭化水素基が好ましい。但しＬ^b3及びＬ^b4の合計炭素数の上限は１３である。
Ｌ^b5は、炭素数１〜１５のの脂肪族炭化水素基を表し、この脂肪族炭化水素基は脂肪族飽和炭化水素基が好ましい。
Ｌ^b6及びＬ^b7は、それぞれ独立に、炭素数１〜１５の脂肪族炭化水素基を表し、これらの脂肪族炭化水素基は脂肪族飽和炭化水素基が好ましい。但しＬ^b6及びＬ^b7の合計炭素数の上限は１６である。
Ｌ^b8は、炭素数１〜１４の脂肪族炭化水素基を表し、この脂肪族炭化水素基は脂肪族飽和炭化水素基が好ましい。
Ｌ^b9及びＬ^b10は、それぞれ独立に、炭素数１〜１１の脂肪族炭化水素基を表し、これらの脂肪族炭化水素基は脂肪族飽和炭化水素基が好ましい。但しＬ^b9及びＬ^b10の合計炭素数の上限は１２である。
本レジスト組成物に用いる酸発生剤としては、これらの中でも、式（ｂ１−１）で表される２価の基をＬ^b1として有する酸発生剤（Ｂ１）が好ましく、Ｌ^b2が単結合又はメチレン基である式（ｂ１−１）で表される２価の基を、Ｌ^b1として有する酸発生剤（Ｂ１）がより好ましい。 Examples of those in which the methylene group constituting the aliphatic hydrocarbon group of L ^b1 is replaced with an oxygen atom or a carbonyl group include the following formulas (b1-1), (b1-2), and (b1-3) ), Formula (b1-4), Formula (b1-5), and Formula (b1-6) [Formula (b1-1) to Formula (b1-6)]. Incidentally, the formula (b1-1) ~ formula represents a bond in (b1-6) * is described in conjunction the right in equation (B1), the left bond is, C (Q ¹⁾ ( Q ² ) is bonded to the carbon atom, and the right bond is bonded to Y. The same applies to specific examples of the following formulas (b1-1) to (b1-6).

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

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

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

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

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

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

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

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

As above-mentioned, Y represents the C1-C18 monovalent | monohydric aliphatic hydrocarbon group which may have a substituent. Among these aliphatic hydrocarbon groups, Y is preferably an alkyl group or an alicyclic hydrocarbon group, and is an alkyl group having 1 to 6 carbon atoms or an alicyclic hydrocarbon group having 3 to 12 carbon atoms, More preferred is an alicyclic hydrocarbon group having 3 to 12 carbon atoms.
When the aliphatic hydrocarbon group of Y has a substituent, the substituent is, for example, a halogen atom (excluding a fluorine atom), a hydroxy group, an alkoxy group having 1 to 12 carbon atoms, an aromatic having 6 to 18 carbon atoms. Group hydrocarbon group, aralkyl group having 7 to 21 carbon atoms, acyl group having 2 to 4 carbon atoms, glycidyloxy group, group represented by — (CH ₂ ) _j2 —O—CO—R ^b1 (wherein R ^b1 represents a hydrocarbon group having 1 to 16 carbon atoms, j2 represents an integer of 0 to 4, and an oxo group. The aromatic hydrocarbon group and aralkyl group referred to here may further have, for example, an alkyl group, a halogen atom or a hydroxy group.
The methylene group constituting the aliphatic hydrocarbon group for Y may be replaced with a group selected from the group consisting of an oxygen atom, a sulfonyl group and a carbonyl group. Examples of the group in which the methylene group constituting the alicyclic hydrocarbon group is replaced with an oxygen atom, a sulfonyl group or a carbonyl group include, for example, a cyclic ether group (one or two of the methylene groups constituting the alicyclic hydrocarbon group are A group in which an oxygen atom is substituted), a cyclic ketone group (a group in which one or two methylene groups constituting an alicyclic hydrocarbon group are replaced by a carbonyl group), a sultone ring group (which constitutes an alicyclic hydrocarbon group) Two adjacent methylene groups in the methylene group are replaced with oxygen atoms and sulfonyl groups, respectively, and a lactone ring group (two methylene groups adjacent in the methylene group constituting the alicyclic hydrocarbon group, A group in which an oxygen atom and a carbonyl group are substituted, respectively).

これらの中でも、好ましくは式（Ｙ１）〜式（Ｙ１９）のいずれかで表される基であり、より好ましくは式（Ｙ１１）、式（Ｙ１４）、式（Ｙ１５）又は式（Ｙ１９）で表される基であり、さらに好ましくは式（Ｙ１１）又は式（Ｙ１４）で表される基である。 In particular, as the group in which —CH ₂ — in the alicyclic hydrocarbon group of Y is replaced by —O—, —SO ₂ — or —CO—, groups represented by the formula (Y12) to the formula (Y26) are included. Can be mentioned.
In particular, examples of the alicyclic hydrocarbon group for Y include groups represented by formulas (Y1) to (Y26).

Among these, Preferably it is group represented by either of Formula (Y1)-Formula (Y19), More preferably, it is represented by Formula (Y11), Formula (Y14), Formula (Y15) or Formula (Y19). And more preferably a group represented by formula (Y11) or formula (Y14).

Examples of Y include the following.

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

Specific examples of the sulfonate anion include sulfonate anions represented by any one of the formulas (b1-1-1) to (b1-1-1-9). In the sulfonate anion represented by any one of formulas (b1-1-1) to (b1-1-1-9), L ^b1 is preferably a group represented by formula (b1-1). Hereinafter, such a sulfonate anion is sometimes referred to as “anion (b1-1-1)” depending on the formula number.

  Specific examples of the sulfonate anion represented by any one of the formulas (b1-1-1) to (b1-1-9) include sulfonate anions described in JP 2010-204646 A, for example. be able to.

Examples of the organic cation (Z ⁺ ) in the acid generator (B1) include an onium cation, 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 organic cation represented by any one of the following formulas (b2-1) to (b2-4) [hereinafter referred to as the number of each formula in some cases]. Depending on the case, it is referred to as “cation (b2-1)”. ].

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

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

The alkylcarbonyloxy group for R ^b12 is a group in which the acyl group already exemplified 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-alkyl-2-adamantyl group, 1- (1 -Adamantyl) -1-alkyl group and isobornyl group.
Preferred examples of the aromatic hydrocarbon group for R ^b12 include phenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-cyclohexylphenyl group, 4-methoxyphenyl group, And biphenylyl and naphthyl groups.
A group in which an aromatic hydrocarbon group of R ^b12 and an alkyl group are bonded is typically an aralkyl group.
Examples of the ring formed by combining the combination of R ^b9 and R ^b10 include, for example, a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium ring. Etc.
Examples of the ring formed by combining the combination of R ^b11 and R ^b12 include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

  Specific examples of the cation (b2-1), cation (b2-2), cation (b2-3), and cation (b2-4) include those described in JP 2010-204646 A.

式（ｂ２−１−１）中、
Ｒ^b19、Ｒ^b20及びＲ^b21は、それぞれ独立に、ハロゲン原子（より好ましくはフッ素原子）、ヒドロキシ基、炭素数１〜１８の脂肪族炭化水素基又は炭素数１〜１２のアルコキシ基を表す。
この脂肪族炭化水素基の炭素数は１〜１２の範囲であると好ましく、炭素数１〜１２のアルキル基及び炭素数４〜１８の脂環式炭化水素基がより好ましく、さらには置換基として、ハロゲン原子、ヒドロキシ基、炭素数１〜１２のアルコキシ基、炭素数６〜１８の芳香族炭化水素基、炭素数２〜４のアシル基又はグリシジルオキシ基を有していてもよい。
ｖ２、ｗ２及びｘ２は、それぞれ独立に０〜５の整数（好ましくは０又は１）を表す。
ｖ２が２以上のとき、複数のＲ^b19は同一でも異なっていてもよく、ｗ２が２以上のとき、複数のＲ^b20は同一でも異なっていてもよく、ｘ２が２以上のとき、複数のＲ^b21は同一でも異なっていてもよい。
なかでも、Ｒ^b19、Ｒ^b20及びＲ^b21は、それぞれ独立に、好ましくは、ハロゲン原子（より好ましくはフッ素原子）、ヒドロキシ基、炭素数１〜１２のアルキル基、又は炭素数１〜１２のアルコキシ基である。 Among the exemplified organic cations, those represented by the formula (b2-1) are preferable, and organic cations represented by the following formula (b2-1-1) [hereinafter referred to as “cation (b2-1-1)” That's it. ], More preferably a triphenylsulfonium cation (in formula (b2-1-1), v2 = w2 = x2 = 0) or a tolylsulfonium cation (in formula (b2-1-1), v2 = w2 = X2 = 1, and R ¹⁹ , R ²⁰ and R ²¹ are all methyl groups).

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

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

  More preferred acid generator (B1) is specifically shown. Such an acid generator (B1) is represented by any of the following formulas (B1-1) to (B1-17). Among them, formula (B1-2), formula (B1-3), formula (B1-6), formula (B1-7), formula (B1-11), formula (B1-12), formula (B1-13) And (B1-14) are more preferred.

<Resin (A)>
As described above, the resin (A) contained in the resist composition is insoluble or hardly soluble in an alkaline aqueous solution, and can be dissolved in an alkaline aqueous solution by the action of an acid (hereinafter, sometimes referred to as “acid action characteristic”). ). By containing this resin (A), this resist composition can manufacture a resist pattern by the effect | action of the acid generate | occur | produced from the acid generator (B) mentioned later. Note that “can be dissolved in an alkaline aqueous solution by the action of an acid” means “insoluble or hardly soluble in an alkaline aqueous solution before contact with an acid, but soluble in an alkaline aqueous solution after contact with an acid”. Means.

  The resin (A) having acid action characteristics has an acid labile group (hereinafter, sometimes referred to as “acid labile group”) in 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), the monomer (a1) may be used alone or in combination of two or more.

［式（１）中、
Ｒ^a1〜Ｒ^a3は、それぞれ独立に、炭素数１〜８のアルキル基又は炭素数３〜２０の脂環式炭化水素基を表すか、Ｒ^a1及びＲ^a2は互いに結合して、これらが結合する炭素原子とともに炭素数３〜２０の環を形成する。＊は結合手を表す。］

［式（２）中、
Ｒ^a1’及びＲ^a2’は、それぞれ独立に、水素原子又は炭素数１〜１２の１価の炭化水素基を表し、Ｒ^a3’は、炭素数１〜２０の炭化水素基を表すか、Ｒ^a2’及びＲ^a3’は互いに結合して、これらが結合する炭素原子とともに炭素数３〜２０の環を形成する。該１価の炭化水素基及び該２価の炭化水素基を構成するメチレン基は、酸素原子又は硫黄原子に置き換わってもよい。＊は結合手を表す。］ <Acid labile group>
The “acid labile group” means a group having a leaving group and capable of leaving the leaving group upon contact with an acid to give 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 to} R ^a3 each independently represents an alkyl group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R ^a1 and R ^a2 are bonded to each other, and these are bonded A ring having 3 to 20 carbon atoms is formed together with carbon atoms to be formed. * Represents a bond. ]

[In Formula (2),
R ^{a1 ′} and R ^{a2 ′} each independently represent a hydrogen atom or a monovalent hydrocarbon group having 1 to 12 carbon atoms, and R ^{a3 ′} represents a hydrocarbon group having 1 to 20 carbon atoms, or R ^{a3 ′ a2 ′} and R ^{a3 ′} are bonded to each other to form a ring having 3 to 20 carbon atoms together with the carbon atom to which they are bonded. The monovalent hydrocarbon group and the methylene group constituting the divalent hydrocarbon group may be replaced with an oxygen atom or a sulfur atom. * Represents a bond. ]

The alkyl group of R ^{a1 to} R ^a3 and the alicyclic hydrocarbon group of the acid labile group (1) include those already exemplified in the above-mentioned range. The alicyclic hydrocarbon group preferably has 5 to 16 carbon atoms.

The case where R ^a1 and R ^a2 are bonded to each other to form a ring is when the group represented by —C (R ^a1 ) (R ^a2 ) (R ^a3 ) is any of the following groups: is there. The number of carbon atoms in the ring formed by combining R ^a1 and R ^a2 is preferably in the range of 3-12.

Examples of the acid labile group (1) include a 1,1-dialkylalkoxycarbonyl group (in the formula (1), groups in which R ^{a1 to} R ^a3 are alkyl groups, preferably a tert-butoxycarbonyl group), 2- Alkyl-2-adamantyloxycarbonyl group (in formula (1), R ^a1 and R ^a2 combine to form an adamantyl ring and R ^a3 is an alkyl group) and 1- (1-adamantyl)- 1-alkylalkoxycarbonyl group (in the formula (1), R ^a1 and R ^a2 are alkyl groups, and R ^a3 is an adamantyl group).

Examples of the R ^{a1 ′} and R ^{a2 ′} hydrocarbon groups of the acid 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, at least one of R ^{a1 ′} and R ^{a2 ′} is preferably a hydrogen atom.

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

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

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

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

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

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

Examples of the monomer (a1) capable of deriving the structural unit (a1-1) include those described in JP-A No. 2010-204646. Of the structural units (a1-1) derived from these, the structural unit (a1-1) represented by any of the following formulas (a1-1-1) to (a1-1-8) is preferable, The structural unit (a1-1) represented by any one of formula (a1-1-1) to formula (a1-1-3) is more preferable.

  On the other hand, examples of the monomer (a1) capable of deriving the structural unit (a1-2) include 1-ethyl-1-cyclopentyl (meth) acrylate, 1-ethyl-1-cyclohexyl (meth) acrylate, and 1-ethyl- Examples include 1-cycloheptyl (meth) acrylate, 1-methyl-1-cyclopentyl (meth) acrylate, and 1-isopropyl-1-cyclopentyl (meth) acrylate.

As the structural unit (a1-2), those represented by any of the following formulas (a1-2-1) to (a1-2-6) are preferable. Among these, the structural unit (a1-2) represented by the formula (a1-2-3) or (a1-2-4) is more preferable, and the structural unit represented by the formula (a1-2-3) (A1-2) is more preferable.

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

  The structural unit (a1-1) and the structural unit (a1-2), which are preferable structural units (a1), have been described above, but the resin (A) is a structural unit having an acid labile group other than these ( a1) [Other structural units (a1)] may be included. In this case, the total content of the structural unit (a1-1) and / or the structural unit (a1-2) in the resin (A) already described is changed to the structural unit (a1-1) and the structural unit (a1-2). ) And / or the total content of other structural units (a1).

<Acid stable structural unit>
Resin (A) is a structural unit not having an acid labile group in addition to a structural unit (a1) having an acid labile group (hereinafter, sometimes referred to as “acid stable structural unit”). The derivatizable monomer is preferably referred to as “acid-stable monomer”). In the resin (A), the acid stable structural unit may have only one type, or may have a plurality of types. 1 type may be sufficient as the acid stable structural unit in resin (A), and 2 or more types may be sufficient as it.
When the resin (A) has the structural unit (a1) and the acid stable structural unit, the acid stable structural unit is obtained by subtracting the content of the acid stable structural unit from 100 mol%. The ratio between 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% / It is 90-20 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 referred to as “acid stable structural unit (a2)”) and / or an acid stable structural unit having a lactone ring (hereinafter referred to as “acid stable structural unit (a3)”). When the present resist composition containing the resin (A) is applied to a substrate, the resin (A) having the coating film formed on the substrate or the composition layer obtained from the coating film is between the substrate It becomes easy to express excellent adhesion, and this resist composition can 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 hydroxyl group into the resin (A). When using exposure using a short wavelength ArF excimer laser (wavelength: 193 nm) as an exposure source, an acid stable structural unit represented by the formula (a2-1) described later is used as a resin ( It is preferable to introduce into A). Thus, each of the acid stable structural units (a2) possessed by the resin (A) can be selected according to the exposure source used for producing the resist pattern, but the acid stable structural units possessed by the resin (A) ( a2) may have only one type of acid stable structural unit (a2) suitable for the type of exposure source, and two or more types of acid stable structural unit (a2) suitable for the type of exposure source. Or an acid stable structural unit (a2) suitable for the type of exposure source and a combination of other acid stable structural units (a2).

式（ａ２−１）中、
Ｌ^a3は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k2−ＣＯ−Ｏ−（ｋ２は１〜７の整数を表す。）を表し、＊はカルボニル基（−ＣＯ−）との結合手を表す。
Ｒ^a14は、水素原子又はメチル基を表す。
Ｒ^a15及びＲ^a16は、それぞれ独立に、水素原子、メチル基又はヒドロキシ基を表す。
ｏ１は、０〜１０の整数を表す。 One specific example of the acid stable structural unit (a2) is one represented by the following formula (a2-1) (hereinafter sometimes referred to as “acid stable structural unit (a2-1)”).

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

L ^a3 is preferably an oxygen atom or a group represented by —O— (CH ₂ ) _k2 —CO—O—, wherein k2 is an integer of 1 to 4, more preferably an oxygen atom or — O—CH ₂ —CO—O—, more preferably an oxygen atom.
R ^a14 is preferably a methyl group.
R ^a15 is preferably a hydrogen atom.
R ^a16 is preferably a hydrogen atom or a hydroxy group.
o1 is preferably an integer of 0 to 3, more preferably 0 or 1.

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

  As described above, the exemplified acid stable structural unit (a2-1) is derived from, for example, an acid stable monomer described in JP 2010-204646 A. Among these, the acid stable structural unit represented by any one of formula (a2-1-1), formula (a2-1-2), formula (a2-1-3) and formula (a2-1-4) (A2-1) is more preferable, and the acid stable structural unit (a2-1) represented by the formula (a2-1-1) or (a2-1-3) is more preferable.

  When the resin (A) has an acid stable structural unit (a2-1), the content ratio is preferably in the range of 3 to 40 mol% with respect to all the structural units of the resin (A), and 5 to 35 The range of mol% is more preferable, and the range of 5 to 30 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 hydroxyl group among the acid stable structural units which have a hydroxy group is demonstrated. The acid stable structural unit is preferably one represented by the following formula (a2-0) (hereinafter sometimes referred to as “acid stable structural unit (a2-0)”).

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

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

Among the acid stable structural units (a2-0), those represented by any of the following formulas (a2-0-1) and (a2-0-2) are preferable. The monomer (a1) capable of deriving such a structural unit is described in, for example, JP 2010-204634 A.

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

  When the resin (A) has an acid stable structural unit (a2-0), the content ratio may be 90 mol% or less with respect to the total structural unit of the resin (A), preferably It is the range of 10-85 mol%, More preferably, it is the range of 15-80 mol%.

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

［式（ａ３−１）中、
Ｌ^a4は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）を表す。＊はカルボニル基との結合手を表す。
Ｒ^a18は、水素原子又はメチル基を表す。
ｐ１は０〜５の整数を表す。
Ｒ^a21は炭素数１〜４の脂肪族炭化水素基を表し、ｐ１が２以上の場合、複数のＲ^a21は同一でも異なっていてもよい。
式（ａ３−２）中、
Ｌ^a5は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）を表す。＊はカルボニル基との結合手を表す。
ｑ１は、０〜３の整数を表す。
Ｒ^a22は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表し、ｑ１が２以上の場合、複数のＲ^a22は同一でも異なっていてもよい。
式（ａ３−３）中、
Ｌ^a6は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）を表す。＊はカルボニル基との結合手を表す。
Ｒ^a20は、水素原子又はメチル基を表す。
ｒ１は、０〜３の整数を表す。
Ｒ^a23は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表し、ｒ１が２以上の場合、複数のＲ^a23は同一でも異なっていてもよい。］ The acid stable structural unit (a3) is preferably one represented by the following formula (a3-1), formula (a3-2) or formula (a3-3). Resin (A) may have only 1 type among these, and may have 2 or more types. In the following description, what is represented by the formula (a3-1) is referred to as “acid-stable structural unit (a3-1)”, and what is represented by the formula (a3-2) is “acid-stable structural unit ( a3-2) ”, and the compound represented by formula (a3-3) is referred to as“ acid-stable structural unit (a3-3) ”.

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

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

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

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

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

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

  As an acid stable monomer which can derive | lead an acid stable structural unit (a3-3), what was described in Unexamined-Japanese-Patent No. 2010-204646 can be mentioned, for example.

  When the resin (A) has an acid stable structural unit (a3-3), the content ratio is preferably in the range of 5 to 50 mol% with respect to all the structural units of the resin (A). The range of mol% is more preferable, and the range of 15 to 40 mol% is more preferable.

  As described above, the structural unit (a1-1) or the structural unit (a1-2) suitable as the structural unit (a1) of the resin (A), the acid stable structural unit (a2) and the acid stable structure suitable as the acid stable structural unit. Although the unit (a3) has been described in detail, structural units other than these may be included, and examples of the structural unit include structural units well known in the art.

<Method for producing resin (A)>
The resin (A) is obtained by copolymerizing the monomer (a1) for deriving the structural unit (a1), more preferably the monomer (a1) and an acid stable monomer for deriving the acid stable structural unit. More preferably, the monomer (a1), the acid stable structural unit (a2) and / or the acid stable structural unit (a3) for deriving the structural unit (a1-1) and / or the structural unit (a1-2) are derived. It is a copolymer of an acid stable monomer.
The resin (A) further preferably has a structural unit (a1-1) having an adamantyl group as the structural unit (a1). As the acid stable structural unit (a2), it is preferable to use a structural unit (a2-1) having a hydroxyadamantyl group. The acid stable structural unit (a3) includes at least an acid stable structural unit (a3-1) having a γ-butyrolactone ring and an acid stable structural unit (a3-2) having a condensed ring of a γ-butyrolactone ring and a norbornane ring. It is preferable to have one. 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)>
As already described, the present resist composition may contain a basic compound (C).

  The basic compound (C) is preferably a basic amine, an ammonium salt or a combination thereof, and the amine and the ammonium salt preferably have no sulfur atom in the molecule. Examples of amines include aliphatic amines and aromatic amines. Aliphatic amines include primary amines, secondary amines and tertiary amines. As the basic compound (C), preferably, a compound represented by any one of the formulas (C1) to (C8) is exemplified, and a compound represented by the formula (C1-1) is more preferred.

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

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

［式（Ｃ１−１）中、
Ｒ^c2及びＲ^c3は、前記と同義である。
Ｒ^c4は、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数５〜１０の脂環式炭化水素又は炭素数６〜１０の芳香族炭化水素基を表す。
ｍ３は０〜３の整数を表し、ｍ３が２以上のとき、複数のＲ^c4は、互いに同一でも異なってもよい。］

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

［式（Ｃ２）、式（Ｃ３）及び式（Ｃ４）中、
Ｒ^c5、Ｒ^c6、Ｒ^c7及びＲ^c8は、それぞれ独立に、Ｒ^c1と同義である。
Ｒ^c9は、炭素数１〜６のアルキル基、炭素数３〜６の脂環式炭化水素基又は炭素数２〜６のアルカノイル基を表す。
ｎ３は０〜８の整数を表し、ｎ３が２以上のとき、複数のＲ^c9は、互いに同一でも異なってもよい。］

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

［式（Ｃ５）及び式（Ｃ６）中、
Ｒ^c10、Ｒ^c11、Ｒ^c12、Ｒ^c13及びＲ^c16は、それぞれ独立に、Ｒ^c1と同義である。
Ｒ^c14、Ｒ^c15及びＲ^c17は、それぞれ独立に、Ｒ^c4と同義である。
ｏ３及びｐ３は、それぞれ独立に０〜３の整数を表し、ｏ３が２以上であるとき、複数のＲ^c14は互いに同一でも異なってもよい。ｐ３が２以上であるとき、複数のＲ^c15は互いに同一でも異なってもよい。
Ｌ^c1は、炭素数１〜６のアルカンジイル基、−ＣＯ−、−Ｃ（＝ＮＨ）−、−Ｓ−又はこれらを組合せた２価の基を表す。］

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

［式（Ｃ７）及び式（Ｃ８）中、
Ｒ^c18、Ｒ^c19及びＲ^c20は、それぞれ独立に、Ｒ^c4と同義である。
ｑ３、ｒ３及びｓ３は、それぞれ独立に０〜３の整数を表し、ｑ３が２以上であるとき、複数のＲ^c18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 represents an integer of 0 to 3, and when q3 is 2 or more, the plurality of R ^c18 may be the same or different from each other. When r3 is 2 or more, the plurality of R ^c19 may be the same as or different from each other. When s3 is 2 or more, the plurality of R ^c20 may be the same as or different from each other.
L ^c2 represents a single bond or an 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-diphenyl Examples include ethane, 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 and 2,2′-dipiconylamine, bipyridine and the like.

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

<Solvent (D)>
As already described, the resist composition preferably contains a solvent (D).
The solvent (D) contained in the resist composition contains the resist composition on the substrate in the production of a resist pattern, which will be described later, and the solubility according to the type and amount of the salt (I) and the resin (A). An optimal one can be appropriately selected from the viewpoint that the applicability at the time of applying an object is improved.

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

  The resist composition is a salt (I), an acid generator (B) [preferably an acid generator that generates sulfonic acid, and more preferably a fluorine-containing acid generator. And a resin (A). It is preferable to contain a solvent (D). Moreover, a basic compound (C) may be contained as needed. Furthermore, the resist composition may contain additives (additives for resist compositions) other than the salt (I) and the basic compound (C) as long as the characteristics are not significantly impaired. Such an additive is hereinafter referred to as “component (F)”. Examples of the component (F) include additives widely used in the art, and examples include a sensitizer, a dissolution inhibitor, a surfactant, a stabilizer, and a dye.

<This resist composition and its preparation method>
Then, the preparation method of this resist composition containing salt (I), an acid generator (B), and resin (A) is demonstrated.
The resist composition is preferably prepared by mixing the salt (I), the acid generator (B) and the resin (A) in the presence of the solvent (D).
Or
It can be prepared by mixing the salt (I), the acid generator (B), the resin (A) and the basic compound (C). Moreover, a component (F) may be mixed as needed. In such mixing, the mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can select the suitable temperature range from the range of 10-40 degreeC according to the solubility with respect to solvent (D), such as a kind (resin (A)), such as resin (A). An appropriate mixing time can be selected from 0.5 to 24 hours depending on the mixing temperature. The mixing means is not particularly limited, and stirring and mixing can be used.

  A preferable range of the content of the salt (I) in the resist composition is determined based on the content of the acid generator (B). Specifically, the total content of the salt (I) and the acid generator (B) is preferably about 0.1 to 35% by mass with respect to the mass of the solid content of the resist composition. Preferably it is about 1-30 mass%, Especially preferably, it is about 10-25 mass%. In addition, the ratio of the content of the salt (I) and the acid generator (B) is represented by [salt (I)] / [acid generator (B)] and is in the range of 5/95 to 95/5. Is preferable, the range of 10/90 to 90/10 is more preferable, and the range of 15/85 to 85/15 is more preferable. However, when the salt (I) works as an acid generator, the resist composition may not contain the acid generator (B). In addition, the mass of the “solid content” here means the total of components obtained by removing the solvent (D) from the resist composition. The solid content can be measured by a known analysis means such as liquid chromatography or gas chromatography.

  A preferable range of the content ratio of the resin (A) in the resist composition is determined based on the solid content of the resist composition. Specifically, the resin (A) is preferably 80% by mass or more based on the mass of the solid content.

  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.

  When the solvent (D) is contained in the resist composition, the content 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 resist composition. For example, it is 99.9 mass% or less, Preferably it is 99 mass% or less.

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

  Thus, each of the salt (I), the resin (A), the acid generator (B), and the solvent (D), the basic compound (C), or the component (F) that is used as necessary is preferably contained. After mixing in an amount, the resist composition can be prepared by filtration using a filter having a pore size of about 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 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 composition for semiconductor microfabrication, such as a spin coater. Thus, a coating film made of the present resist composition is formed on the substrate. The film thickness of the coating film can be adjusted by variously adjusting the conditions (coating conditions) of the coating apparatus, and by applying an appropriate preliminary experiment, the coating film can be applied to have a desired film thickness. You can choose the conditions. Various substrates to be subjected to microfabrication can be selected as the substrate before applying the resist composition. The substrate can be washed or an antireflection film can be formed before applying the resist composition. For example, a commercially available composition for an organic antireflection film can be used for forming the antireflection film.

In the step (2), the solvent [solvent (D)] is removed from the resist composition coated on the substrate, that is, the coated film. Such solvent removal is performed, for example, by evaporating the solvent (D) from the coating film by a heating means using a heating device such as a hot plate, a decompression means using a decompression device, or a combination of these means. Is done. The conditions for the heating means and the decompression means are adjusted according to the type of the solvent (D) contained in the resist composition. For example, in the heating means (hot plate heating) using a hot plate, What is necessary is just to make surface temperature into the range of about 50-200 degreeC. 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, by removing the solvent (D) from the coating film, a composition layer is formed on the substrate.

Step (3) is a step of exposing the composition layer, and preferably the composition layer is exposed using an exposure machine. At this time, exposure is performed through a mask corresponding to a desired pattern to be finely processed. 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 laser (wavelength 157 nm), a solid-state laser light source (YAG or Various types of laser light such as a semiconductor laser or the like that converts wavelength of laser light to 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.
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 part, the acid generator (salt (I) and / or acid generator (B)) contained in the composition layer receives exposure energy to generate an acid, and further by the action of the generated acid. The acid labile group in the resin (A) undergoes a deprotection reaction, and as a result, the resin (A) in the composition layer of the exposed portion becomes soluble in the aqueous alkali 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, the composition layer in the exposed portion and the composition layer in the unexposed portion are significantly different in solubility in the alkaline aqueous solution.

  In step (4), a heat treatment for further promoting the progress of the deprotecting group reaction that may occur in the exposed portion is performed. For the heat treatment, a heating means using a hot plate shown in the step (2) is employed. In the hot plate heating in step (4), the surface temperature of the hot plate is preferably about 50 to 200 ° C, more preferably about 70 to 150 ° C.

Step (5) is a step of developing the heated composition layer, and preferably the heated composition layer is developed with a developing device. By contacting the heated composition layer with an aqueous alkali solution, the exposed composition layer is dissolved in the alkaline aqueous solution, and leaving the unexposed composition layer on the substrate, a resist pattern is formed on the substrate. Is manufactured.
The alkaline aqueous solution used here is referred to as “alkaline developer”, and those used in this technical field can be used. Examples of the alkaline aqueous solution include an aqueous solution of tetramethylammonium hydroxide and an aqueous solution of (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline).

  The resist pattern manufactured on the substrate as described above is preferably rinsed with ultrapure water or the like to further remove moisture remaining on the substrate and the resist pattern.

  According to the resist pattern manufacturing method including the steps (1) to (5) as described above, the present resist composition can manufacture a resist pattern having excellent line width roughness (LWR).

<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 EB, or a resist composition for EUV exposure machines.

Hereinafter, the present invention will be described more specifically with reference to examples.
In Examples and Comparative Examples, “%” and “part” representing the content or amount used are based on mass unless otherwise specified.
Further, the weight average molecular weight is a value obtained by gel permeation chromatography (HLC-8120GPC type manufactured by Tosoh Corporation, column is TSKgel Multipore HXL-M3, solvent is tetrahydrofuran) using polystyrene as a standard product.
The structure of the compound was confirmed by NMR (GX-270 type or EX-270 type; manufactured by JEOL), mass spectrometry (LC; Agilent 1100 type, MASS; Agilent LC / MSD type or LC / MSD TOF type). did.

式（Ｉ−１−ａ）で表される化合物４．０部とメタノール２０部とを混合した溶液に、酸化銀（Ｉ）２．７部を加え、室温（約２３℃程度）下、１８時間攪拌した。反応混合溶液に、ヨウ化メチル３．３８部を加えて、さらに室温下、１８時間攪拌した。反応混合液を濾過し、得られたろ液を濃縮した。得られた残渣を、メタノール及び酢酸エチルの混合溶液により再結晶を行い、式（Ｉ−１）で表される塩（Ｉ）２．０部を得た。 Example 1: Synthesis of salt (I) represented by formula (I-1)

To a solution obtained by mixing 4.0 parts of the compound represented by the formula (I-1-a) and 20 parts of methanol, 2.7 parts of silver (I) oxide was added, and the mixture was added at room temperature (about 23 ° C.) at 18 ° C. Stir for hours. To the reaction mixture, 3.38 parts of methyl iodide was added, and the mixture was further stirred at room temperature for 18 hours. The reaction mixture was filtered and the resulting filtrate was concentrated. The obtained residue was recrystallized with a mixed solution of methanol and ethyl acetate to obtain 2.0 parts of the salt (I) represented by the formula (I-1).

¹ H-NMR (DMSO-d ₆ ): δ = 8.12-8.02 (1H, m), 7.83-7.74 (1H, m), 7.71-7.59 (2H, m ), 3.10 (6H, s)

式（Ｉ−１９−ａ）で表される化合物１０．０部とメタノール５０部とを混合した溶液に、酸化銀（Ｉ）６．９部を加え、室温（約２３℃程度）下、１８時間攪拌した。反応混合溶液に、ヨウ化ブチル１６．４部を加えて、さらに室温下、１８時間攪拌した。反応混合液を濾過し、得られたろ液を濃縮した。得られた残渣を、メタノール及び酢酸エチルの混合溶液により再結晶を行い、式（Ｉ−１９）で表される塩（Ｉ）４．１部を得た。 Example 2: Synthesis of salt (I) represented by formula (I-19)

To a solution obtained by mixing 10.0 parts of the compound represented by the formula (I-19-a) and 50 parts of methanol, 6.9 parts of silver (I) oxide is added, and the mixture is added at room temperature (about 23 ° C.) at 18 ° C. Stir for hours. To the reaction mixture, 16.4 parts of butyl iodide was added, and the mixture was further stirred at room temperature for 18 hours. The reaction mixture was filtered and the resulting filtrate was concentrated. The obtained residue was recrystallized with a mixed solution of methanol and ethyl acetate to obtain 4.1 parts of the salt (I) represented by the formula (I-19).

¹ H-NMR (DMSO-d ₆ ): δ = 8.10-8.01 (1H, m), 7.84-7.74 (1H, m), 7.72-7.55 (2H, m ), 3.54 (2H, t, J = 7.75 Hz), 3.08 (3H, s), 1.78-1.26 (4H, m), 0.87 (3H, t, J = 7) .09Hz)

以下、これらのモノマーを、その式番号に応じて、「モノマー（Ｍ−２）」などという。 Synthesis Example: Resin Synthesis The compounds (monomers) used in the resin synthesis are shown below.

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

Synthesis Example 1: Synthesis of Resin A1 Monomer (M-5) 18.00 parts, monomer (M-4) 3.85 parts, monomer (M-2) 2.78 parts, and monomer (M-3) 16. 34 parts were charged into the reactor (molar ratio; monomer (M-5): monomer (M-4): monomer (M-2): monomer (M-3) = 35: 10: 6: 49), all monomers 1.5 times the amount of propylene glycol monomethyl ether acetate was added to make a solution. 0.90 mol% and 2.70 mol% of azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) as initiators were added to the total monomer amount, respectively, and heated at 75 ° C for about 5 hours. . Thereafter, the obtained reaction mixed solution was poured into a large amount of methanol / water mixed solvent to precipitate a resin, and this resin was filtered. The resin thus obtained was again dissolved in propylene glycol monomethyl ether acetate, and the resulting solution was poured into a methanol / water mixed solvent to precipitate the resin. A resin having an average molecular weight of about 8.4 × 10 ³ was obtained with a yield of 72%. This resin has the following structural units, and this resin is referred to as resin A1.

Examples 3 and 4 and Comparative Example 1
A mixture obtained by mixing and dissolving the components shown in Table 1 was filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition. In the table, “-” indicates that the content is 0.

＜塩（Ｉ）＞
Ｉ−１：式（Ｉ−１）で表される塩
＜塩基性化合物：クエンチャー＞
Ｃ１：２，６−ジイソプロピルアニリン
＜溶剤（Ｄ）＞
Ｄ１：
プロピレングリコールモノメチルエーテルアセテート １３０．０部
プロピレングリコールモノメチルエーテル ２００．０部
γ−ブチロラクトン ２０．０部 <Resin (A)>
A1: Resin A1
<Acid generator (B)>
B1: Acid generator represented by formula (B1-3)

<Salt (I)>
I-1: salt represented by formula (I-1) <basic compound: quencher>
C1: 2,6-Diisopropylaniline <Solvent (D)>
D1:
Propylene glycol monomethyl ether acetate 130.0 parts Propylene glycol monomethyl ether 200.0 parts γ-butyrolactone 20.0 parts

An organic antireflection coating composition [ARC-29SR-309; manufactured by Nissan Chemical Co., Ltd.] was applied onto a 12-inch silicon wafer and baked at 205 ° C. for 60 seconds to obtain a thickness. A 75 nm organic antireflection coating was formed.
Next, the above resist composition was spin-coated on the organic antireflection film so that the film thickness after drying was 80 nm.
The obtained silicon wafer was pre-baked (PB) at 100 ° C. for 60 seconds on a direct hot plate. The obtained wafer was exposed using an ArF excimer scanner for immersion exposure [XT: 1900 Gi; manufactured by ASML, NA = 1.35, Dipole35, σout / in = 0.97 / 0.77, Y deflection]. The line and space pattern was subjected to immersion exposure by changing the amount stepwise.
After exposure, post-exposure baking (PEB) was performed at 80 ° C. for 60 seconds on a hot plate, and paddle development was further performed with a 2.38 mass% tetramethylammonium hydroxide aqueous solution for 60 seconds.

  In each resist film, the exposure amount at which the 42 nm line and space pattern becomes an exposure amount of 1: 1 was defined as the effective sensitivity.

Line width roughness evaluation (LWR): The line width of the resist pattern after the lithography process is observed with a scanning electron microscope. good), 2.1 nm or more was designated as “b” (bad). The results are shown in Table 2.

  If the resist composition containing the salt of the present invention is used, a resist pattern having excellent line width roughness (LWR) can be produced. Therefore, the salt of the present invention and the resist composition containing the salt are industrially useful.

Claims (9)

  A salt having one tertiary sulfur atom and one carboxylate group in the molecule. The salt according to claim 1 represented by formula (I).

[In the formula (I),
A ¹ and A ² are each independently a monovalent organic group having 1 to 18 carbon atoms,
A ³ is a divalent organic group having 1 to 18 carbon atoms. A ¹ and A ² may be bonded to each other to form a heterocyclic ring together with the sulfur atom to which they are bonded, and A ¹ and A ³ are bonded to each other, together with the sulfur atom to which they are bonded A heterocycle may be formed. ] A ¹ and A ^{2 in} the formula (I) are each independently a monovalent aliphatic hydrocarbon group which may have a group selected from the following substituent group P1, or the following substituent group: The salt according to claim 2, which is a monovalent aromatic hydrocarbon group which may have a group selected from P2.
[Substituent group P1]
Hydroxy group and aryl group having 6 to 12 carbon atoms [Substituent group P2]
Hydroxy group, alkyl group having 1 to 6 carbon atoms, and alkoxy group having 1 to 6 carbon atoms The salt according to claim 2, wherein A ¹ and A ^{2 in} the formula (I) are each independently an alkyl group having 1 to 6 carbon atoms. The salt according to claim 2, wherein A ^{3 in the} formula (I) is a divalent organic group containing an aromatic ring. The salt according to claim 2, wherein A ^{3 in the} formula (I) is a divalent aromatic hydrocarbon group.   The salt according to any one of claims 1 to 6, which is used as an additive for a resist composition. A salt according to any one of claims 1 to 7;
A resin that is insoluble or hardly soluble in an aqueous alkaline solution and that can be dissolved in an aqueous alkaline solution by the action of an acid;
A resist composition containing an acid generator. (1) The process of apply | coating the resist composition of Claim 8 on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer,
(4) a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating,
A method for producing a resist pattern including: