JP2013083957A - Resist composition and method of manufacturing resist pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resist composition to manufacture a resist pattern with excellent line edge roughness.SOLUTION: A resist composition contains a compound represented by the formula (I), resin and an acid generation agent. The resin contains a structural unit represented by the formula (a1-0) and is insoluble or poorly soluble in an aqueous alkali solution but becomes soluble in the aqueous alkali solution by the action of acid.

Description

  The present invention relates to a resist composition and a method for producing a resist pattern.

  As a semiconductor microfabrication technique, an optical lithography technique using short wavelength light as an exposure source has been studied, and a resist composition is used for the optical lithography technique. As such a resist composition, for example, Patent Document 1 describes a resist composition containing 1,2,4,5-tetrafluoro-3,6-diiodobenzene as an additive.

JP 2005-508527A

  However, when the conventionally known resist composition is used in lithography technology using an electron beam or extreme ultraviolet (EUV) as an exposure source, the line edge roughness (LER) of the resulting resist pattern is not necessarily satisfactory. There was no case.

[式（Ｉ）中、
ｚ１は１〜４の整数を表す。
Ｒ^１は、カルボキシ基、ヒドロキシ基、カルボキシ基を有する脂肪族炭化水素基又はヒドロキシ基を有する脂肪族炭化水素基を表す。
ｚ２は、１〜３の整数を表す。ｚ２が２以上のとき、複数のＲ^１は、互いに同一又は相異なる。
Ａは、置換基を有していてもよい炭素数６〜２０の芳香族炭化水素基を表す。］

［式（ａ１−０）中、
Ｌ^aaは、酸素原子又は^＊−Ｏ−（ＣＨ₂）_ｇ1−ＣＯ−Ｏ−（ｇ１は１〜７の整数を表し、＊はカルボニル基との結合手を表す。）を表す。
Ｒ^aｄは、水素原子又はメチル基を表す。
Ｒ^aa、Ｒ^ab及びＲ^acは、それぞれ独立に、炭素数１〜８のアルキル基、炭素数３〜２０の脂環式炭化水素基又はこれらを組み合わせた基を表すか、Ｒ^aa及びＲ^abは互いに結合して炭素数２〜２０の２価の炭化水素基を形成する。］ The present invention includes the following inventions.
[1] containing a compound represented by formula (I), a resin and an acid generator,
A resist composition, which is a resin in which the resin contains a structural unit represented by the formula (a1-0), is insoluble or hardly soluble in an alkaline aqueous solution, and becomes soluble in an alkaline aqueous solution by the action of an acid.

[In the formula (I),
z1 represents the integer of 1-4.
R ¹ represents a carboxy group, a hydroxy group, an aliphatic hydrocarbon group having a carboxy group or an aliphatic hydrocarbon group having a hydroxy group.
z2 represents an integer of 1 to 3. When z2 is 2 or more, the plurality of R ¹ are the same or different from each other.
A represents an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent. ]

[In the formula (a1-0),
L ^aa represents an oxygen atom or ^* —O— (CH ₂ ) _g1 —CO—O— (g1 represents an integer of 1 to 7, and * represents a bond to a carbonyl group).
R ^ad represents a hydrogen atom or a methyl group.
R ^aa , R ^ab and R ^ac each independently represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a combination thereof, or R ^aa and R ^ab Combine with each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms. ]

[式（ＩＩ）中、
ｚ３は、１〜４の整数を表す。
Ｒ^１は、前記と同じ意味を表す。
ｚ４は、１〜３の整数を表す。ｚ４が２以上のとき、複数のＲ^１は、互いに同一又は相異なる。
Ｒ^２は、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基又はアミノ基を表す。
ｚ５は、０又は１を表す。
ただし、ｚ３＋ｚ４＋ｚ５は、６以下である。］ [2] The resist composition according to [1], wherein the compound represented by the formula (I) is a compound represented by the formula (II).

[In the formula (II),
z3 represents an integer of 1 to 4.
R ¹ represents the same meaning as described above.
z4 represents an integer of 1 to 3. When z4 is 2 or more, the plurality of R ¹ are the same or different from each other.
R ² represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an amino group.
z5 represents 0 or 1.
However, z3 + z4 + z5 is 6 or less. ]

［式（ａ１−１）中、
Ｌ^a1は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−を表し、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。
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。］ [3] The resist composition according to [1] or [2], wherein the structural unit represented by the formula (a1-0) is a structural unit represented by the formula (a1-1).

[In the formula (a1-1),
L ^a1 represents an oxygen atom or ^* —O— (CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, and * represents a bond with a carbonyl group.
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. ]

［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のアルキル基又は置換基を有していてもよい炭素数３〜１８の脂環式炭化水素基を表し、該アルキル基及び該脂環式炭化水素基を構成するメチレン基は、酸素原子、スルホニル基又はカルボニル基に置き換わっていてもよい。
Ｚ⁺は、有機カチオンを表す。］ [4] The resist composition according to any one of [1] to [3], wherein the acid generator is an acid generator represented by the formula (B1).

[In the formula (B1),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a 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 an alkyl group having 1 to 18 carbon atoms which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent. The methylene group constituting the alicyclic hydrocarbon group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group.
Z ⁺ represents an organic cation. ]

[5] The resist composition according to any one of [1] to [4], further containing a solvent.
[6] (1) A step of applying the resist composition according to any one of [1] to [5] on a substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) A method for producing a resist pattern, comprising a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating.
[7] The method for producing a resist pattern according to [6], wherein (3) is a step of exposing the composition layer to an electron beam or EUV.

[式（Ｉ）中、
ｚ１は１〜４の整数を表し、ｚ２は１〜３の整数を表す。
Ｒ^１は、群ＲＸから選ばれる基であり、ｍが２以上の場合、複数存在するＲ^１はそれぞれ独立に群ＲＸから選ばれる基である。
Ａは、（ｚ１＋ｚ２）価の炭素数６〜２０の芳香族炭化水素基を表す。
群ＲＸは、カルボキシ基、ヒドロキシ基、カルボキシ基を有する脂肪族炭化水素基及び、ヒドロキシ基を有する脂肪族炭化水素基からなる。］
（Ａ）式（ａ１−１）又は式（ａ１−２）で表される構造単位を含み、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可溶となる樹脂

［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。］
（Ｂ）酸発生剤
〔９〕電子線又はＥＵＶを露光源とする露光に用いられる、前記〔１〕〜〔５〕及び〔８〕のいずれか一つ記載のレジスト組成物。 Furthermore, the present invention includes the following inventions.
[8] A resist composition containing the following (X), (A) and (B).
(X) Compound represented by formula (I)

[In the formula (I),
z1 represents an integer of 1 to 4, and z2 represents an integer of 1 to 3.
R ¹ is a group selected from group RX, and when m is 2 or more, a plurality of R ¹ are each independently a group selected from group RX.
A represents a (z1 + z2) valent aromatic hydrocarbon group having 6 to 20 carbon atoms.
Group RX consists of an aliphatic hydrocarbon group having a carboxy group, a hydroxy group, a carboxy group, and an aliphatic hydrocarbon group having a hydroxy group. ]
(A) Resin that contains the structural unit represented by formula (a1-1) or formula (a1-2), is insoluble or hardly soluble in alkaline aqueous solution, and is soluble in alkaline aqueous solution by the action of acid

[In the formula (a1-1),
L ^a1 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k1 —CO—O— (k1 represents an integer of 1 to 7, and * represents a bond to a carbonyl group). Represent.
R ^a4 represents a hydrogen atom or a methyl group.
R ^a6 represents an aliphatic hydrocarbon group having 1 to 10 carbon atoms.
m1 represents the integer of 0-14.
In formula (a1-2),
L ^a2 is an oxygen atom or ^* —O— (CH ₂ ) _k1 —CO—O— (k1 is as defined above).
) Represents a group represented by
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. ]
(B) Acid generator [9] The resist composition according to any one of [1] to [5] and [8], which is used for exposure using an electron beam or EUV as an exposure source.

  According to the resist composition of the present invention, a resist pattern having excellent line edge roughness (LER) can be produced, for example, when used in an optical lithography technique using an electron beam or EUV as an exposure source.

The resist composition of the present invention (hereinafter sometimes referred to as “the present resist composition”)
A compound represented by formula (I) (hereinafter sometimes referred to as “compound (I)”),
A resin (hereinafter referred to as “resin (A)”) containing a structural unit represented by the formula (a1-0), insoluble or hardly soluble in an alkaline aqueous solution, and soluble in an alkaline aqueous solution by the action of an acid. And acid generator (B).
Furthermore, the resist composition of the present invention preferably contains a quencher (C) and / or a solvent (D).

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

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

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

  The cyclic aliphatic hydrocarbon group (hereinafter sometimes referred to as “alicyclic hydrocarbon group”) includes both monocyclic and polycyclic.

The monovalent monocyclic aliphatic hydrocarbon group is, for example, a group obtained by removing one hydrogen atom from a cycloalkane represented by the following formulas (KA-1) to (KA-7).

The monovalent polycyclic aliphatic hydrocarbon group is, for example, a group obtained by removing one hydrogen atom from an alicyclic hydrocarbon represented by the following formulas (KA-8) to (KA-19). .

  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 thereof include a halogen atom, a hydroxy group, an alkoxy group, an acyl group, an acyloxy group, an aryl group, an aralkyl group, and an aryloxy group.

Examples of alkoxy groups include methoxy group (C ₁ ), ethoxy group (C ₂ ), propoxy group (C ₃ ), butoxy group (C ₄ ), pentyloxy group (C ₅ ), hexyloxy group (C ₆ ), heptyl Examples thereof include an oxy group (C ₇ ), an octyloxy group (C ₈ ), a decyloxy group (C ₁₀ ), and a dodecyloxy group (C ₁₂ ).
Examples of the acyl group include acetyl group (C ₂ ), propionyl group (C ₃ ), butyryl group (C ₄ ), valeryl group (C ₅ ), hexanoyl group (C ₆ ), heptanoyl group (C ₇ ), octanoyl group ( C ₈ ), decanoyl group (C ₁₀ ) and dodecanoyl group (C ₁₂ ) and other alkyl groups and carbonyl groups bonded, and benzoyl group (C ₇ ) and other aryl groups and carbonyl groups bonded Can be mentioned.
Examples of the acyloxy group include an acetyloxy group, a propionyloxy group, a butyryloxy group, and an isobutyryloxy group.
Examples of the aralkyl group include benzyl group (C ₇ ), phenethyl group (C ₈ ), phenylpropyl group (C ₉ ), naphthylmethyl group (C ₁₁ ), and naphthylethyl group (C ₁₂ ).
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.

The monovalent aromatic hydrocarbon group typically includes an aryl group.
As an aryl group, 1 hydrogen atom is obtained from an aromatic compound such as benzene (C ₆ ), naphthalene (C ₁₀ ), anthracene (C ₁₄ ), biphenyl (C ₁₂ ), phenanthrin (C ₁₄ ), and fluorene (C ₁₃ ). A group that has been removed is listed. Examples of the divalent aromatic hydrocarbon group include an arylene group in which one hydrogen atom is further removed from the aryl group exemplified here. Thus, the valence of the aromatic hydrocarbon group is set according to the number of hydrogen atoms removed from the aromatic compound.

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

[式（Ｉ）中、
ｚ１は１〜４の整数を表す。
Ｒ^１は、カルボキシ基、ヒドロキシ基、カルボキシ基を有する脂肪族炭化水素基又はヒドロキシ基を有する脂肪族炭化水素基を表す。
ｚ２は、１〜３の整数を表す。ｚ２が２以上のとき、複数のＲ^１は、互いに同一又は相異なる。
Ａは、置換基を有していてもよい炭素数６〜２０の芳香族炭化水素基を表す。］ <Compound (I)>
Compound (I) is represented by formula (I).

[In the formula (I),
z1 represents the integer of 1-4.
R ¹ represents a carboxy group, a hydroxy group, an aliphatic hydrocarbon group having a carboxy group or an aliphatic hydrocarbon group having a hydroxy group.
z2 represents an integer of 1 to 3. When z2 is 2 or more, the plurality of R ¹ are the same or different from each other.
A represents an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent. ]

  The aromatic hydrocarbon group having 6 to 20 carbon atoms of A is preferably an aromatic hydrocarbon group having 6 to 14 carbon atoms, more preferably benzene which may have a substituent, or a substituent. It is a group obtained by removing (z1 + z2) hydrogen atoms from an aromatic ring of a good naphthalene, an optionally substituted biphenyl, or an optionally substituted anthracene. More preferably, it is a group obtained by removing (z1 + z2) hydrogen atoms from the benzene ring of benzene which may have a substituent.

  The aromatic hydrocarbon group of A may have a substituent, and the substituent includes an alkyl group (preferably having 1 to 6 carbon atoms), an alkoxy group (preferably having 1 to 6 carbon atoms), or an amino group. Can be mentioned. When the aromatic hydrocarbon group of A has these substituents, the number of carbon atoms of the aromatic hydrocarbon group of A including the carbon number of the substituent is preferably 20 or less.

[式（ＩＩ）中、
ｚ３は、１〜４の整数を表す。
Ｒ^１は、前記と同じ意味を表す。
ｚ４は、１〜３の整数を表す。ｚ４が２以上のとき、複数のＲ^１は、互いに同一又は相異なる。
Ｒ^２は、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基又はアミノ基を表す。
ｚ５は、０又は１を表す。
ただし、ｚ３＋ｚ４＋ｚ５は、６以下である。］
Ｒ^２は、好ましくは、炭素数１〜６のアルキル基又はアミノ基である。 Compound (I) is preferably a compound represented by formula (II).

[In the formula (II),
z3 represents an integer of 1 to 4.
R ¹ represents the same meaning as described above.
z4 represents an integer of 1 to 3. When z4 is 2 or more, the plurality of R ¹ are the same or different from each other.
R ² represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an amino group.
z5 represents 0 or 1.
However, z3 + z4 + z5 is 6 or less. ]
R ² is preferably an alkyl group having 1 to 6 carbon atoms or an amino group.

Specific examples of compound (I) are shown below.

  Compound (I) may be a commercially available product that can be easily obtained from the market, or a product produced by a known production technique. Among these, the formula (I-1) to the formula (I-7), the formula (I-12) to the formula (I-15), and the formula are easier to obtain or easier to produce. Compounds represented by (I-17) and formula (I-18), respectively, are preferred.

<Resin (A)>
As described above, the resin (A) is insoluble or hardly soluble in an alkaline aqueous solution and has a characteristic of being soluble in an alkaline aqueous solution by the action of an acid. 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) has the above-described characteristics by having a group (hereinafter, sometimes referred to as “acid-decomposable group”) that decomposes under the action of an acid in the molecule. Such a resin (A) is a monomer having an acid-decomposable 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. When manufacturing resin (A), monomer (a1) may use 1 type and may use 2 or more types together.

［式（１）中、
Ｒ^a1、Ｒ^ａ２及びＲ^a3は、それぞれ独立に、炭素数１〜８のアルキル基又は炭素数３〜２０の脂環式炭化水素基を表すか、Ｒ^a1及びＲ^a2は互いに結合して炭素数２〜２０の２価の炭化水素基を形成する。＊は結合手を表す。］ <Acid-decomposable group>
The “acid-decomposable group” means a group that has a leaving group and forms a hydrophilic group (for example, a hydroxy group or a carboxy group) by leaving the leaving group upon contact with an acid. Examples of the acid-decomposable group include a group represented by the formula (1) (hereinafter referred to as “acid-decomposable group (1)” in some cases) and a group represented by the formula (2) (hereinafter, sometimes represented by And “acid-decomposable group (2)”).

[In Formula (1),
R ^a1 , R ^a2 and R ^a3 each independently represent an alkyl group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R ^a1 and R ^a2 are bonded to each other to form carbon A divalent hydrocarbon group of 2 to 20 is formed. * Represents a bond. ]

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

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

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

Examples of the group represented by —C (R ^a1 ) (R ^a2 ) (R ^a3 ) when R ^a1 and R ^a2 are bonded to each other to form a divalent hydrocarbon group include the following groups: Can be mentioned. The divalent hydrocarbon group preferably has 3 to 12 carbon atoms.

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

Examples of the hydrocarbon group of R ^{a1 ′ to} R ^{a3 ′} of the acid-decomposable group (2) include an alkyl group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or a group in which two or more of these are combined. It is.
At least one of R ^{a1 ′} and R ^{a2 ′} is preferably a hydrogen atom.

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

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

  Especially, the monomer (a1) which has an acid-decomposable group (1) and / or an acid-decomposable group (2) is preferable, and has an acid-decomposable group (1) and / or an acid-decomposable group (2). A (meth) acrylic monomer is particularly preferred.

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

［式（ａ１−０）中、
Ｌ^aaは、酸素原子又は^＊−Ｏ−（ＣＨ₂）_ｇ1−ＣＯ−Ｏ−（ｇ１は１〜７の整数を表し、＊はカルボニル基との結合手を表す。）を表す。
Ｒ^aｄは、水素原子又はメチル基を表す。
Ｒ^aa、Ｒ^ab及びＲ^acは、それぞれ独立に、炭素数１〜８のアルキル基、炭素数３〜２０の脂環式炭化水素基又はこれらを組み合わせた基を表すか、Ｒ^aa及びＲ^abは互いに結合して炭素数２〜２０の２価の炭化水素基を形成する。］
Ｒ^aa、Ｒ^ab及びＲ^acとしては、式（１）のＲ^a1〜Ｒ^a3におけるものと同様の基が挙げられる。アルキル基と脂環式炭化水素基とを組み合わせた基としては、メチルシクロヘキシル基、ジメチルシクロヘキシル基、シクロヘキシルメチル基、イソボルニル基等が挙げられる。
Ｒ^aa、Ｒ^ab及びＲ^acは、好ましくは、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^aa及びＲ^abは互いに結合して炭素数２〜２０の２価の炭化水素基を形成する。 <Structural Unit Represented by Formula (a1-0)>
The resin (A) includes a structural unit represented by the formula (a1-0) (hereinafter, sometimes referred to as “structural unit (a1-0)”) as the structural unit (a1).

[In the formula (a1-0),
L ^aa represents an oxygen atom or ^* —O— (CH ₂ ) _g1 —CO—O— (g1 represents an integer of 1 to 7, and * represents a bond to a carbonyl group).
R ^ad represents a hydrogen atom or a methyl group.
R ^aa , R ^ab and R ^ac each independently represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a combination thereof, or R ^aa and R ^ab Combine with each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms. ]
^{Examples of} R ^aa , R ^ab and R ^ac include the same groups as those in R ^{a1 to} R ^a3 of formula (1). Examples of the group in which an alkyl group and an alicyclic hydrocarbon group are combined include a methylcyclohexyl group, a dimethylcyclohexyl group, a cyclohexylmethyl group, and an isobornyl group.
R ^aa , R ^ab and R ^ac preferably each independently represent an alkyl group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or R ^aa and R ^ab are bonded to each other. Thus, a divalent hydrocarbon group having 2 to 20 carbon atoms is formed.

［式（ａ１−１）中、
Ｌ^a1は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−（ｋ１は１〜７の整数を表し、＊はカルボニル基との結合手を表す。）で表される基を表す。
Ｒ^a4は、水素原子又はメチル基を表す。
Ｒ^a6は、炭素数１〜１０の脂肪族炭化水素基を表す。
ｍ１は０〜１４の整数を表す。
式（ａ１−２）中、
Ｌ^a2は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k1−ＣＯ−Ｏ−（ｋ１は前記と同義である。
）で表される基を表す。
Ｒ^a5は、水素原子又はメチル基を表す。
Ｒ^a7は、炭素数１〜１０の脂肪族炭化水素基を表す。
ｎ１は０〜１０の整数を表す。
ｎ１’は０〜３の整数を表す。］ The structural unit (a1-0) is a structural unit represented by the formula (a1-1) (hereinafter sometimes referred to as “structural unit (a1-1)”) and a structure represented by the formula (a1-2). At least one selected from the group consisting of units (hereinafter sometimes referred to as “structural units (a1-2)”) is preferable. The resin (A) may have the structural unit (a1-1) as a single species, may have a plurality of types, or may have the structural unit (a1-2) as a single species. A plurality of types may be included, and the structural unit (a1-1) and the structural unit (a1-2) may be combined.

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

L ^a1 and L ^a2 are preferably an oxygen atom or a group represented by * —O— (CH ₂ ) _k1 —CO—O—, wherein k1 is an integer of 1 to 4, more preferably an oxygen atom. or * -O-CH ₂ -CO-O- and, still more preferably an oxygen atom.
R ^a4 and R ^a5 are preferably methyl groups.
The aliphatic hydrocarbon groups represented by R ^a6 and R ^a7 include linear and cyclic aliphatic hydrocarbon groups and a combination thereof, and preferably an alkyl group having 1 to 8 carbon atoms or 3 to 10 carbon atoms. More preferably an alkyl group having 1 to 8 carbon atoms or an alicyclic hydrocarbon group having 3 to 8 carbon atoms, still more preferably an alkyl group having 1 to 6 carbon atoms or carbon. It is an alicyclic hydrocarbon group of number 3-6.
m1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 is preferably an integer of 0 to 3, more preferably 0 or 1.
n1 ′ is preferably 0 or 1.

As the structural unit (a1-1), structural units respectively represented by formulas (a1-1-1) to (a1-1-8) are preferable, and formulas (a1-1-1) to (a1-1) are preferable. -4) is more preferred.

  Examples of the monomer capable of deriving these structural units (a1-1) include those described in JP 2010-204646 A.

The structural unit (a1-2) is preferably a structural unit represented by each of the formulas (a1-2-1) to (a1-2-12)], more preferably the formula (a1- 2-3), structural units (a1-2) represented by (a1-2-4), (a1-2-7) and (a1-2-8), respectively, more preferably 2-3) and structural units represented by (a1-2-7), respectively.

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

  The structural unit (a1-0) is preferably at least one selected from the group consisting of the structural unit (a1-1) and the structural unit (a1-2), and more preferably the structural unit (a1-1).

The content of the structural unit (a1-0) contained in the resin (A) is preferably 10 to 95 mol%, and preferably 15 to 90 mol% with respect to all the structural units (100 mol%) of the resin (A). More preferably, 20-85 mol% is further more preferable, and 20-60 mol% is especially preferable.
When structural unit (a1-0) is structural unit (a1-1) and / or structural unit (a1-2), the preferable range of the total content is the same as described above.
When the resin (A) has a structural unit (a1) having an adamantyl group (particularly preferably, the structural unit (a1-1)), the sum of the structural units (a1) in the resin (A) ( 100 mol%), the structural unit (a1) having an adamantyl group is preferably 15 mol% or more. Resin (A) having a structural unit (a1) having an adamantyl group at such a content ratio tends to have good dry etching resistance of a resist pattern produced from a resist composition containing the resin (A). is there.

式（ａ１−３）中、
Ｒ^a9は、水素原子、置換基（例えばヒドロキシ基）を有していてもよい炭素数１〜３の脂肪族炭化水素基、カルボキシ基、シアノ基、又は−ＣＯＯＲ^a13で表される基を表し、Ｒ^a13は、炭素数１〜８の脂肪族炭化水素基を表し、該脂肪族炭化水素基に含まれる水素原子はヒドロキシ基などに置換されていてもよく、該脂肪族炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。Ｒ^a10、Ｒ^a11及びＲ^a12は、それぞれ独立に、炭素数１〜１２の脂肪族炭化水素基を表すか、或いはＲ^a10及びＲ^a11は互いに結合して環を形成している。該脂肪族炭化水素基及に含まれる水素原子はヒドロキシ基などで置換されていてもよく、該脂肪族炭化水素基を構成するメチレン基は、酸素原子又はカルボニル基に置き換わっていてもよい。 <Other structural unit (a1)>
The resin (A) may have a structural unit (a1) other than the structural unit (a1-0).
Examples of the other structural unit (a1) include a structural unit derived from a monomer represented by the following formula (a1-3) (hereinafter sometimes referred to as “monomer (a1-3)”). When the resin (A) has a structural unit derived from the monomer (a1-3), the main chain contains a rigid norbornane ring. Therefore, the resist composition containing such a resin (A) is There is a tendency that a resist pattern having excellent dry etching resistance can be produced.

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

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

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

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

  When the resin (A) has a structural unit derived from the monomer (a1-3), the content ratio is preferably 10 to 95 mol% with respect to all the structural units of the resin (A), and 15 to 90 mol. % Is more preferable, and 20 to 85 mol% is more preferable.

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

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

Among “an alkyl group having 1 to 6 carbon atoms which may have a halogen atom”, the alkyl group includes those already exemplified in the range of 1 to 6 carbon atoms. As the alkyl group having a halogen atom, an alkyl group having a fluorine atom is preferable. Examples of the alkyl group having a fluorine atom include a perfluoroalkyl group.
R ¹⁰ is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and particularly preferably a hydrogen atom or a methyl group.
The alkoxy group of R ¹¹ includes those already exemplified in the range of 1 to 6 carbon atoms. Among them, an alkoxy group having 1 to 4 carbon atoms is preferable, a methoxy group and an ethoxy group are more preferable, and a methoxy group is particularly preferable. preferable.
The acyl group and acyloxy group of R ¹¹ include those already exemplified in the range of 2 to 4 carbon atoms.
The hydrocarbon groups of R ¹² and R ¹³ are those having 1 to 12 carbon atoms, and the hydrocarbon group of Y ^a3 is the aliphatic hydrocarbon group exemplified above in the range of 1 to 18 carbon atoms. Contains any of the aromatic hydrocarbon groups.
The aliphatic hydrocarbon group of X ^a2 is a divalent chain hydrocarbon group, a divalent alicyclic hydrocarbon group, or a divalent group in which a chain hydrocarbon group and an alicyclic hydrocarbon group are combined. And groups obtained by appropriately combining the groups already exemplified in the range of 1 to 17 carbon atoms.

As a monomer (a1-4), the monomer described in Unexamined-Japanese-Patent No. 2010-204646 is mentioned, for example. Especially, the monomer respectively represented by Formula (a1-4-1)-Formula (a1-4-7) is preferable, and each is represented by Formula (a1-4-1)-Formula (a1-4-5). Monomers are more preferred.

  When the resin (A) has a structural unit derived from the monomer (a1-4), the content ratio is preferably 10 to 95 mol% with respect to all the structural units of the resin (A), and 15 to 90 mol%. Is more preferable, and 20-85 mol% is especially preferable.

式（ａ１−３）中、
Ｒ^a8は、水素原子又はメチル基を表す。
Ａ^１は、単結合、酸素原子又はカルボニル基を表す。
Ａ^２は炭素数１〜６のアルカンジイル基を表す。
Ｒ^a1〜Ｒ^a3は、前記と同義である。 Examples of the other structural unit (a1) include a structural unit derived from a monomer represented by the following formula (a1-5) (hereinafter sometimes referred to as “monomer (a1-5)”).

In formula (a1-3),
R ^a8 represents a hydrogen atom or a methyl group.
A ¹ represents a single bond, an oxygen atom or a carbonyl group.
A ² represents an alkanediyl group having 1 to 6 carbon atoms.
R ^{a1 to} R ^a3 are as defined above.

R ^a1 to R ^a3 of the structural unit (a1-5) are each independently a alkyl group having 1 to 8 carbon atoms, a divalent 2-11 carbon atoms bonded R ^a1 and R ^a2 each other preferably forms a hydrocarbon group. Ring R ^a1 and R ^a2 are formed by bound be a divalent hydrocarbon group having 2 to 11 carbon atoms with each other, such as an adamantane ring or cyclohexane ring.
An alkyl group having 1 to 8 carbon atoms, a methyl group, an ethyl group, a propyl group, a butyl group, a linear alkyl group such as heptyl or hexyl group.
Specific examples of the alkanediyl group of A ² include those already exemplified in the range of 1 to 6 carbon atoms.

Specific examples of the structural unit (a1-5) are shown below, for example.

  When the resin (A) has the structural unit (a1-5), the content is preferably 3 to 80 mol%, more preferably 5 to 70 mol%, based on all the structural units of the resin (A). 5 to 60 mol% is particularly preferable.

<Structural unit not having acid-decomposable group>
Resin (A) is a structural unit having no acid-decomposable group in addition to the structural unit (a1-0) (hereinafter sometimes referred to as “acid-stable structural unit”, a monomer capable of deriving the acid-stable structural unit) Are preferably referred to as “acid-stable monomers”). Resin (A) may have only 1 type of acid stable structural units, and may have multiple types.

  When the resin (A) has an acid stable structural unit, the content ratio of the acid stable structural unit may be determined based on the content ratio of the structural unit (a1). The molar ratio ([structural unit (a1)] / [acid-stable structural unit]) between the content of the structural unit (a1) and the content of the acid-stable structural unit is preferably 10:90 to 80:20. More preferably, it is 20: 80-60: 40. 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.

The acid stable structural unit is preferably a structural unit having a hydroxy group or a lactone ring. An acid stable structural unit having a hydroxy group (hereinafter, sometimes referred to as “acid stable structural unit (a2)”.
) And / or an acid-stable structural unit having a lactone ring (hereinafter, sometimes referred to as “acid-stable structural unit (a3)”) is used as the resist composition containing the resin (A). When applied to a substrate, the coating film formed on the substrate, or the composition layer obtained from the coating film, easily develops excellent adhesion to the substrate, and this resist composition has good resolution. A resist pattern can be manufactured.

<Acid stable structural unit (a2)>
The acid stable structural unit (a2) can be selected according to the type of exposure source used when producing a resist pattern from the resist composition. 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 as an exposure source, the acid stable structural unit (a2) is The acid stable structural unit (a2) having a phenolic hydroxy group is preferred. When exposure using a short wavelength ArF excimer laser (wavelength: 193 nm) as an exposure source is used, the acid stable structural unit (a2) is preferably an acid stable structural unit (a2) having an alcoholic hydroxy group. Thus, each of the acid stable structural units (a2) possessed by the resin (A) can be selected according to the exposure source used for producing the resist pattern, but the acid stable structural units possessed by the resin (A) ( a2) may have only one type of acid stable structural unit (a2) suitable for the type of exposure source, and two or more types of acid stable structural unit (a2) suitable for the type of exposure source. Or an acid stable structural unit (a2) suitable for the type of exposure source and a combination of other acid stable structural units (a2).

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

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

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

  A monomer for deriving the acid stable structural unit (a2-1) is described in, for example, JP-A No. 2010-204646. Among these, the acid stable structural units represented by formula (a2-1-1), formula (a2-1-2), formula (a2-1-3) and formula (a2-1-4) are more preferable. The acid stable structural unit represented by formula (a2-1-1) or (a2-1-3) is more preferable.

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

式（ａ２−０）中、
Ｒ^a30は、ハロゲン原子を有してもよい炭素数１〜６のアルキル基、水素原子又はハロゲン原子を表す。
Ｒ^a31は、ハロゲン原子、ヒドロキシ基、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシ基、炭素数２〜４のアシル基、炭素数２〜４のアシルオキシ基、アクリロイルオキシ基又はメタクリロイルオキシ基を表す。
ｍａは０〜４の整数を表す。ｍａが２以上の整数である場合、複数のＲ^a31は同一でも異なっていてもよい。 Examples of the acid stable structural unit having a phenolic hydroxy group include those represented by the following formula (a2-0) (hereinafter referred to as “acid stable structural unit (a2-0)” in some cases).

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

^Examples of the “C 1-6 alkyl group ^optionally having a halogen atom for R ^a30 ” include groups similar to those represented by the formula (a1-4) R ¹⁰ .
R ^a30 is preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, more preferably a hydrogen atom, a methyl group or an ethyl group, and particularly preferably a hydrogen atom or 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), in the following formula (a2-0-1), formula (a2-0-2), formula (a2-0-3) and formula (a2-0-4) Those represented respectively are preferred. An acid stable monomer capable of deriving such a structural unit is described in, for example, JP 2010-204634 A.

  The resin (A) containing the acid stable structural unit (a2-0) is obtained by protecting the phenolic hydroxy group of the monomer that induces the acid stable structural unit (a2-0) with a protective group such as an acetyl group, It is preferable to produce by polymerizing using this protected monomer and then deprotecting the protecting group. Further, it is more preferable to carry out the deprotection treatment with a base so that the acid-decomposable group of the structural unit (a1) is not significantly impaired.

  When resin (A) has an acid stable structural unit (a2-0), the content is preferably 5 to 90 mol%, more preferably 10 to 85 mol%, based on all structural units of resin (A). Preferably, 15 to 80 mol% is more preferable.

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

［式（ａ３−１）中、
Ｌ^a4は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a18は、水素原子又はメチル基を表す。
ｐ１は０〜５の整数を表す。
Ｒ^a21は炭素数１〜４の脂肪族炭化水素基を表し、ｐ１が２以上の場合、複数のＲ^a21は互いに同一又は相異なる。
式（ａ３−２）中、
Ｌ^a5は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
ｑ１は、０〜３の整数を表す。
Ｒ^a19は、水素原子又はメチル基を表す。
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は互いに同一又は相異なる。
式（ａ３−３）中、
Ｌ^a6は、酸素原子又は^＊−Ｏ−（ＣＨ₂）_k3−ＣＯ−Ｏ−（ｋ３は１〜７の整数を表す。）で表される基を表す。＊はカルボニル基との結合手を表す。
Ｒ^a20は、水素原子又はメチル基を表す。
ｒ１は、０〜３の整数を表す。
Ｒ^a23は、カルボキシ基、シアノ基又は炭素数１〜４の脂肪族炭化水素基を表し、ｒ１が２以上の場合、複数のＲ^a23は互いに同一又は相異なる。］ 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 a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a18 represents a hydrogen atom or a methyl group.
p1 represents an integer of 0 to 5.
R ^a21 represents an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and when p1 is 2 or more, the plurality of R ^a21 are the same or different from each other.
In formula (a3-2),
L ^a5 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
q1 represents an integer of 0 to 3.
R ^a19 represents a hydrogen atom or a methyl group.
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, the plurality of R ^a22 are the same or different from each other.
In formula (a3-3),
L ^a6 represents an oxygen atom or a group represented by ^* —O— (CH ₂ ) _k3 —CO—O— (k3 represents an integer of 1 to 7). * Represents a bond with a carbonyl group.
R ^a20 represents a hydrogen atom or a methyl group.
r1 represents an integer of 0 to 3.
R ^a23 represents a carboxy group, a cyano group, or an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and when r1 is 2 or more, the plurality of R ^a23 are the same or different from each other. ]

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 are the same or different from each other, when q1 is 2, two R ^a22 are the same or different from each other, and when r1 is 2, two R ^a23 are The same or different from each other.

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

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

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

  Monomers for deriving the acid stable structural unit (a3-1), the acid stable structural unit (a3-2), and the acid stable structural unit (a3-3) are described in, for example, JP-A No. 2010-204646. Among the specific examples of the acid stable structural unit (a3), the formula (a3-1-1) to the formula (a3-1-2), the formula (a3-2-3) to the formula (a3-2-4) Is more preferable, and the acid stable structural unit represented by Formula (a3-1-1) or Formula (a3-2-3) is more preferable.

  When the resin (A) has an acid stable structural unit (a3), the content is preferably from 5 to 70 mol%, more preferably from 10 to 65 mol%, based on all structural units of the resin (A). 10 to 60 mol% is more preferable.

Examples of other acid stable structural units include hydrophobic acid stable structural units.
Specifically, for example, styrene monomers such as styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene; isobornyl acrylate, tricyclodecyl (meth) acrylate, or tetracyclodone. Examples include structural units derived from alicyclic hydrocarbon group-containing (meth) acrylic monomers such as decenyl (meth) acrylate. Of these, structural units derived from styrene monomers are preferred.

  When the resin (A) has such a hydrophobic acid-stable structural unit, the content is preferably 1 to 60 mol%, and 3 to 50 mol% with respect to all the structural units of the resin (A). Is more preferable, and 5-40 mol% is further more preferable.

  The resin (A) may further have a structural unit well known in the resist field in addition to the above structural unit.

<Method for producing resin (A)>
The resin (A) includes a structural unit (a1-0), and preferably includes a structural unit (a1-0) and an acid stable structural unit.
When the resin (A) is a resin containing the structural unit (a1-0) and the acid stable structural unit, the resin (A) copolymerizes the monomer that derives the structural unit (a1-0) and the acid stable monomer. Can be manufactured.
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 content rate of each structural unit contained in resin (A) can be adjusted with the usage rate of each monomer used in order to manufacture resin (A).

When specific examples of the resin (A) are exemplified by a combination of structural units, the following resins (A-1) to (A-18) may be mentioned.

  The weight average molecular weight of the resin (A) is preferably 2,500 or more and 50,000 or less, and more preferably 3,000 or more and 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.

<Acid generator (B)>
The acid generator (B) contained in the resist composition may be either nonionic or ionic, or a mixture thereof. Nonionic acid generators include organic halides, sulfonate esters (for example, 2-nitrobenzyl ester, aromatic sulfonate, oxime sulfonate, N-sulfonyloxyimide, N-sulfonyloxyimide, sulfonyloxyketone, diazonaphthoquinone 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.

  The acid generator (B) includes not only acid generators (particularly photoacid generators) used in the resist field, but also photocationic polymerization initiators, photodecolorants of dyes, photochromic agents, and the like. Known compounds that generate acids by radiation (light) and mixtures thereof can also be used as appropriate. For example, JP-A 63-26653, JP-A 55-164824, JP-A 62-69263, JP-A 63-146038, JP-A 63-163452, JP-A 62-153853, Acid is generated by radiation described in Japanese Utility Model Publication No. 63-146029, US Pat. No. 3,779,778, US Pat. No. 3,849,137, German Patent No. 3914407, European Patent No. 126,712, etc. Can 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のアルキル基又は置換基を有していてもよい炭素数３〜１８の脂環式炭化水素基を表し、該アルキル基及び該脂環式炭化水素基を構成するメチレン基は、酸素原子、スルホニル基又はカルボニル基に置き換わっていてもよい。
Ｚ⁺は、有機カチオンを表す。］ The acid generator (B) is preferably a fluorine-containing acid generator, more preferably an acid generator represented by the following formula (B1) (hereinafter sometimes referred to as “acid generator (B1)”. ). In the following description, among the acid generators (B1), Z ⁺ having a positive charge is referred to as “organic cation”, and a negative charge obtained by removing the organic cation is referred to as “sulfonate anion”. There is.

[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 an alkyl group having 1 to 18 carbon atoms which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent. The methylene group constituting the alicyclic hydrocarbon group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group.
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.
Q ¹ and Q ² are each independently preferably a trifluoromethyl group or a fluorine atom, more preferably a fluorine atom.

Specific examples of the divalent aliphatic saturated hydrocarbon group of L ^b1 include hydrogen from the alkanediyl group exemplified above and the alicyclic saturated hydrocarbons of the above formulas (KA-1) to (KA-19). For example, a group with two atoms removed.

式（ｂ１−１）〜式（ｂ１−６）中、
Ｌ^b2は、単結合又は炭素数１〜１５の脂肪族飽和炭化水素基を表す。
Ｌ^b3は、単結合又は炭素数１〜１２の脂肪族飽和炭化水素基を表す。
Ｌ^b4は、炭素数１〜１３の脂肪族飽和炭化水素基を表す。但しＬ^b3及びＬ^b4の合計炭素数の上限は１３である。
Ｌ^b5は、炭素数１〜１５のの脂肪族飽和炭化水素基を表す。
Ｌ^b6及びＬ^b7は、それぞれ独立に、炭素数１〜１５の脂肪族飽和炭化水素基を表す。但しＬ^b6及びＬ^b7の合計炭素数の上限は１６である。
Ｌ^b8は、炭素数１〜１４の脂肪族飽和炭化水素基を表す。
Ｌ^b9及びＬ^b10は、それぞれ独立に、炭素数１〜１１の脂肪族飽和炭化水素基を表す。
但しＬ^b9及びＬ^b10の合計炭素数の上限は１２である。
Ｌ^b1は、式（ｂ１−１）で表される基が好ましく、＊−ＣＯ−Ｏ−＊又は＊−ＣＯ−Ｏ−ＣＨ_２−＊がより好ましい。 Examples of the methylene group constituting the aliphatic saturated hydrocarbon group of L ^b1 replaced by an oxygen atom or a carbonyl group include groups represented by formulas (b1-1) to (b1-6), respectively. Can be mentioned. In addition, Formula (b1-1)-Formula (b1-6) has described the right and left according to Formula (B1), and the left hand is out of two joints each represented by *. , C (Q ¹ ) (Q ² ), and the right bond is bonded to Y. The same applies to specific examples of the following formulas (b1-1) to (b1-6).

In formula (b1-1) to formula (b1-6),
L ^b2 represents a single bond or an aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b3 represents a single bond or an aliphatic saturated hydrocarbon group having 1 to 12 carbon atoms.
L ^b4 represents an aliphatic saturated hydrocarbon group having 1 to 13 carbon atoms. However, the upper limit of the total carbon number of L ^b3 and L ^b4 is 13.
L ^b5 represents an aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms.
L ^b6 and L ^b7 each independently represent an aliphatic saturated hydrocarbon group having 1 to 15 carbon atoms. However, the upper limit of the total carbon number of L ^b6 and L ^b7 is 16.
L ^b8 represents an aliphatic saturated hydrocarbon group having 1 to 14 carbon atoms.
L ^b9 and L ^b10 each independently represent an aliphatic saturated hydrocarbon group having 1 to 11 carbon atoms.
However, the upper limit of the total carbon number of L ^b9 and L ^b10 is 12.
L ^b1 is preferably a group represented by the formula (b1-1), more preferably * —CO—O— * or * —CO—O—CH ₂ — *.

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

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

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

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

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

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

The alkyl group of Y includes those already exemplified in the range of 1 to 18 carbon atoms. Among them, the alkyl group of 1 to 6 carbon atoms is preferable. The alicyclic hydrocarbon group of Y is also 3 to 18 carbon atoms. Examples include groups represented by the following formulas (Y1) to (Y11), including those already exemplified in the range.
As described above, the methylene group constituting the alkyl group and the alicyclic hydrocarbon group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group. Examples of the group in which the methylene group constituting the alicyclic hydrocarbon group is replaced with an oxygen atom or a carbonyl group include groups represented by the following formulas (Y12) to (Y26), respectively.

  The alicyclic hydrocarbon group of Y is preferably a group represented by each of the formulas (Y1) to (Y19), more preferably the formula (Y11), the formula (Y14), the formula (Y15), or the formula ( Y19), more preferably a group represented by formula (Y11) or formula (Y14).

Examples of the substituent that the alkyl group of Y may have include, for example, a halogen atom, a hydroxy group, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, an aromatic hydrocarbon group having 6 to 18 carbon atoms, and carbon. number 2-4 acyl group, a glycidyl group or a _{- (CH 2) j2 -O-} CO-R b1 group (wherein, R ^b1 represents an alkyl group having 1 to 16 carbon atoms, fat 3 to 16 carbon atoms Represents a cyclic hydrocarbon group or an aromatic hydrocarbon group having 6 to 18 carbon atoms, j2 represents an integer of 0 to 4).
Examples of the substituent that the alicyclic hydrocarbon group of Y may have include, for example, a halogen atom, a hydroxy group, an alkyl group having 1 to 12 carbon atoms that may have a hydroxy group, and 3 to 3 carbon atoms. 16 alicyclic hydrocarbon groups, alkoxy groups having 1 to 12 carbon atoms, aromatic hydrocarbon groups having 6 to 18 carbon atoms, aralkyl groups having 7 to 21 carbon atoms, acyl groups having 2 to 4 carbon atoms, glycidyloxy Group or — (CH ₂ ) _j2 —O—CO—R ^b1 group (wherein R ^b1 is an alkyl group having 1 to 16 carbon atoms, an alicyclic hydrocarbon group having 3 to 16 carbon atoms, or 6 to 6 carbon atoms). Represents an aromatic hydrocarbon group of 18. j2 represents an integer of 0 to 4). Of the substituents shown here, the alkyl group, alicyclic hydrocarbon group, aromatic hydrocarbon group, and aralkyl group may further have a substituent.

The halogen atom may be any of those already exemplified.
Specific examples of the alkyl group, the alicyclic hydrocarbon group, the alkoxy group, the aromatic hydrocarbon group, the aralkyl group, and the acyl group include those already exemplified in each carbon number range. In addition, examples of the alkyl group having a hydroxy group include a hydroxymethyl group and a hydroxyethyl group.

In the alicyclic hydrocarbon group which is preferable Y, examples of the alicyclic hydrocarbon group having a substituent include the following.

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

The sulfonate anion constituting the acid generator (B1) is preferably an anion represented by each of the formulas (b1-1-1) to (b1-1-9). In the following formula, L ^b2 has the same meaning as described above, and is preferably a group represented by the formula (b1-1). R ^b2 and R ^b3 are each independently defined as a substituent that may optionally be present in the aliphatic hydrocarbon group of Y, preferably an alkyl group having 1 to 4 carbon atoms, and particularly preferably a methyl group. .

  The sulfonate anion represented by the formula (b1-1-1) to the formula (b1-1-9) is described in, for example, Japanese Patent Application Laid-Open No. 2010-204646.

Examples of the organic cation (Z ⁺ ) constituting the acid generator (B1) include organic onium cations such as organic sulfonium cation, organic iodonium cation, organic ammonium cation, benzothiazolium cation, and organic phosphonium cation. Are an organic sulfonium cation and an organic iodonium cation, and more preferably an arylsulfonium cation.

The organic cation (Z ⁺ ) is preferably a cation represented by each of the formulas (b2-1) to (b2-4).

In formula (b2-1) to formula (b2-4),
R ^b4 , R ^b5 and R ^b6 each independently represents a hydrocarbon group having 1 to 30 carbon atoms. This hydrocarbon group is preferably an alkyl group having 1 to 30 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms. 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 ^b4 and R ^b5 may together form a 3- to 12-membered ring (preferably a 3- to 7-membered ring) with the sulfur atom to which they are bonded.
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 ^b9 and R ^b10 may together form a 3- to 12-membered ring (preferably a 3- to 7-membered ring) with the sulfur atom to which they are bonded. —CH ₂ — contained in the ring may be replaced by —O—, —SO— or —CO—.
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 ^b12 represents an alkyl group having 1 to 12 carbon atoms, an alicyclic hydrocarbon group having 3 to 18 carbon atoms, or an aromatic hydrocarbon group having 6 to 18 carbon atoms, and the aromatic hydrocarbon group has You may have a C1-C12 alkyl group, a C1-C12 alkoxy group, a C3-C18 alicyclic hydrocarbon group, or a C1-C12 alkylcarbonyloxy group.
R ^b11 and R ^b12 may form a 3- to 12-membered ring (preferably a 3- to 7-membered ring) together with —CH—CO— to which they are bonded, May be replaced by an oxygen atom, a sulfur atom or a carbonyl group.

^{R b13, R b14, R b15} , R b16, R b17 and R ^b18 each independently represent a hydroxy group, an alkyl group or an alkoxy group having 1 to 12 carbon atoms 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 are the same or different from each other, when p2 is 2 or more, the plurality of R ^b14 are the same or different from each other, and when s2 is 2 or more, a plurality of R ^{b15 Are} the same or different from each other, and when t2 is 2 or more, the plurality of R ^b18 are the same or different from each other.

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. The alkyl group for R ^{b9 to} R ^b11 preferably has 1 to 12 carbon atoms.
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. The alicyclic hydrocarbon group of R ^{b9 to} R ^b11 preferably has 3 to 18 carbon atoms, and more preferably 4 to 12 carbon atoms.
Preferable examples of the aromatic hydrocarbon group for R ^b12 include a phenyl group, a biphenylyl group, and a naphthyl group. Preferred examples of the aromatic hydrocarbon group having an alkyl group or an alicyclic hydrocarbon group include 4-methylphenyl group, 4-ethylphenyl group, 4-tert-butylphenyl group, 4-cyclohexylphenyl group and 4 -Methoxyphenyl group and the like.
A group in which an aromatic hydrocarbon group of R ^b12 and an alkyl group are bonded is typically an aralkyl group.

The ring containing a sulfur atom which may be formed by combining R ^b4 and R ^b5 is any of monocyclic, polycyclic, aromatic, non-aromatic, saturated and unsaturated rings. If it contains one or more sulfur atoms, it may further contain one or more sulfur atoms and / or one or more oxygen atoms. As the ring, a ring having 3 to 18 carbon atoms is preferable, and a ring having 4 to 18 carbon atoms is more preferable.
Examples of the ring formed together with the sulfur atom to which R ^b9 and R ^b10 are bonded include, for example, a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and 1,4-oxathian-4-ium. A ring etc. are mentioned.
Examples of the ring formed with —CH—CO— in which R ^b11 and R ^b12 are bonded include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

  Specific examples of the organic cation represented by the formulas (b2-1) to (b2-4) include those described in JP2010-204646A.

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は、炭素数１〜１２が好ましく、炭素数１〜１２のアルキル基又は炭素数４〜１８の脂環式炭化水素基がより好ましい。
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は互いに同一又は相異なり、ｗ２が２以上のとき、複数のＲ^b20は互いに同一又は相異なり、ｘ２が２以上のとき、複数のＲ^b21は互いに同一又は相異なる。
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, the cation (b2-1) is preferable, and an organic cation represented by the following formula (b2-1-1) [hereinafter referred to as “cation (b2-1-1)” in some cases. ], 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 ^b19 , R ^b20 and R ^b21 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.
This aliphatic hydrocarbon group preferably has 1 to 12 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms or an alicyclic hydrocarbon group having 4 to 18 carbon atoms.
v2, w2 and x2 each independently represent an integer of 0 to 5 (preferably 0 or 1).
When v2 is 2 or more, the plurality of R ^b19 are the same or different from each other. When w2 is 2 or more, the plurality of R ^b20 are the same or different from each other. When x2 is 2 or more, the plurality of R ^b21 are 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. These can be arbitrarily combined, and preferably a combination of any one of anion (b1-1-1) to anion (b1-1-9) and a cation (b2-1-1), and an anion (b1-1) -3) to (b1-1-5) and a combination of a cation (b2-3).

Examples of the acid generator (B1) include salts represented by formulas (B1-1) to (B1-20). Preferably, Formula (B1-1), Formula (B1-2), Formula (B1-3), Formula (B1-6), Formula (B1-11), Formula (B1-12) containing a triarylsulfonium cation And (B1-13), (B1-14), (B1-18), (B1-19) and (B1-20).

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

［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、互いに同一又は相異なる。］

[In the formula (C1-1),
R ^c2 and R ^c3 are as defined above.
R ^c4 represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alicyclic hydrocarbon having 5 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms.
m3 represents an integer of 0 to 3, and when m3 is 2 or more, the plurality of R ^c4 are the same 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、互いに同一又は相異なる。］

[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 are the same 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は互いに同一又は相異なる。ｐ３が２以上であるとき、複数のＲ^c15は互いに同一又は相異なる。
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, the plurality of R ^c14 are the same or different from each other. When p3 is 2 or more, the plurality of R ^c15 are the same 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は互いに同一又は相異なる。ｒ３が２以上であるとき、複数のＲ^c19は互いに同一又は相異なる。ｓ３が２以上であるとき、複数のＲ^c20は互いに同一又は相異なる。
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 are the same or different from each other. When r3 is 2 or more, the plurality of R ^c19 are the same or different from each other. When s3 is 2 or more, the plurality of R ^c20 are the same 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. ]

In Formula (C1) to Formula (C8) and Formula (C1-1), specific examples of the alkyl group, alicyclic hydrocarbon group, aromatic hydrocarbon group, alkoxy group, and alkanediyl group are the number of carbon atoms. Those already exemplified in the scope of.
Examples of the alkanoyl group include acetyl group, 2-methylacetyl group, 2,2-dimethylacetyl group, propionyl group, butyryl group, isobutyryl group, pentanoyl group, and 2,2-dimethylpropionyl group.

  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 Ethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, and the like are preferable. Ropiruanirin. Particularly preferred include 2,6-diisopropylaniline.

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

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

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

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

<Other ingredients>
The resist composition may further contain other components in addition to the components described above (hereinafter sometimes referred to as “component (F)”). The component (F) is not particularly limited, and examples include additives commonly used in the resist field, such as sensitizers, dissolution inhibitors, surfactants, stabilizers, and dyes.

<Preparation method of the present resist composition>
It can be prepared by mixing compound (I), resin (A) and acid generator (B), and solvent (D), basic compound (C) and component (F) used as necessary. it can. The mixing order is arbitrary and is not particularly limited. The temperature at the time of mixing can select an appropriate temperature range from the range of 10-40 degreeC according to the kind with respect to solvent (D), such as a kind, such as compound (I), and compound (I). 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.
The content of each component used when preparing the resist composition can be adjusted by the amount of use thereof.
After mixing each component, it is preferable to filter using a filter having a pore size of about 0.003 to 0.2 μm.

  As for the content rate of resin (A) in this resist composition, 80 mass% or more and 99 mass% or less are preferable with respect to the total amount of solid content of a resist composition. In the present specification, the “solid content of the resist composition” means the total of components excluding the solvent (D) from the total amount of the resist composition. The solid content of the resist composition and the content of each component contained in the resist composition can be measured by known analysis means such as liquid chromatography or gas chromatography.

  The content of the compound (I) is preferably 0.5 to 30% by mass, more preferably 1 to 20% by mass, and further preferably 3 to 15% by mass with respect to 100 parts by mass of the resin (A). It is.

  The content of the acid generator (B) is preferably 1 part by mass or more and 35 parts by mass or less, and more preferably 3 parts by mass or more and 30 parts by mass or less with respect to 100 parts by mass of the resin (A).

  When the basic composition (C) is contained in the resist composition, the content is preferably about 0.01 to 3% by mass with respect to the total solid content of the resist composition.

The content of the solvent (D) can be appropriately adjusted depending on the type of the compound (I), but is preferably 90% by mass or more, more preferably 92% by mass or more, and still more preferably based on the total mass of the resist composition. Is 94% by mass or more, preferably 99.9% by mass or less, more preferably 99.5% by mass or less, and still more preferably 99% by mass or less. Here, in the resist composition in which the content of the solvent (D) is 90% by mass, the solid content in the composition corresponds to 10% by mass.
When the content of the solvent (D) is within the above range, for example, in the method for producing a resist pattern described later, there is an advantage that a composition layer having a thickness of about 30 to 300 nm can be easily formed. In addition, content of this solvent (D) is controllable by the usage-amount of the solvent (D) at the time of preparing this resist composition.

  In addition, when using a component (F) for this resist composition, suitable content can also be adjusted according to the kind of the said component (F).

<Method for producing resist pattern>
A method for producing a resist pattern using the resist composition is as follows:
(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;
(4) A manufacturing method including a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating. Hereinafter, each of the steps shown here is referred to as “step (1)” to “step (5)”.

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

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

In step (3), the composition layer is preferably exposed using an exposure machine. At this time, exposure is performed through a mask (photomask) on which a desired pattern to be finely processed is formed. As an exposure light source of the exposure machine, an ultraviolet light source such as a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), an F ₂ excimer laser (wavelength 157 nm), or an ultra-ultraviolet light (EUV) ) (Wavelength: 13.5 nm), a laser beam from a solid-state laser light source (such as YAG or a semiconductor laser) is used to convert the wavelength and emit a harmonic laser beam in the far ultraviolet region or the vacuum ultraviolet region. be able to. When the exposure light source is an electron beam, direct drawing may be performed without using a mask. In this specification, the irradiation of these radiations may be collectively referred to as “exposure”. Further, the exposure machine may be an immersion exposure machine (ultra pure water or the like is used as the immersion medium). Among these exposure methods, when a resist pattern is produced by exposure to extreme ultraviolet light (EUV) or an electron beam, a resist pattern having a very good line edge roughness (LER) can be produced from the resist composition. Therefore, the present resist composition is particularly suitable as a resist composition for electron beam irradiation or extreme ultraviolet (EUV) exposure.

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

By selecting the type of developer, a positive resist pattern or a negative resist pattern can be produced.
When producing a positive resist pattern from the resist composition, an alkaline aqueous solution is used as a developer. As the alkaline aqueous solution, those known in this technical field called “alkaline developer” can be used. Examples of the alkaline aqueous solution include an aqueous solution of tetramethylammonium hydroxide and an aqueous solution of (2-hydroxyethyl) trimethylammonium hydroxide (commonly called choline). The alkaline developer may contain an additive such as a surfactant.
After development, it is preferable to rinse the resist pattern with ultrapure water or the like to wash the resist pattern, and to further remove moisture remaining on the substrate and the resist pattern.

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

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

<Application>
This resist composition is a resist composition for KrF excimer laser exposure, a resist composition for ArF excimer laser exposure, a resist composition for electron beam (EB) irradiation (resist composition for electron beam) or EUV exposure. It is useful for resist compositions (resist compositions for EUV) and the like. In particular, when it is used for photolithography using an electron beam or EUV as an exposure source, a resist pattern with extremely good line edge roughness can be produced.

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

以下、これらの化合物（モノマー）をその式符号に応じて、「モノマーＡ」などという。 Synthesis of Resin (A) The compound (monomer) used for the synthesis of resin (A) is shown below.

Hereinafter, these compounds (monomers) are referred to as “monomer A” or the like according to their formula symbols.

Synthesis Example 1 [Synthesis of Resin A1]
28.82 parts of 1,4-dioxane was added to 11.18 parts of monomer B, 14.60 parts of p-acetoxystyrene and 3.55 parts of monomer C, and this solution was heated to 87 ° C. 2.96 parts of azobisisobutyronitrile was added as an initiator, and the mixture was kept at 87 ° C. for 6 hours. After cooling, the reaction solution was poured into a mixed solvent of 291.41 parts of methanol and 124.89 parts of ion-exchanged water to precipitate a resin, which was filtered. The obtained resin and 2.93 parts of 4-dimethylaminopyridine were added to the same amount of methanol as the resin and heated to reflux for 15 hours. After cooling, the resulting reaction solution was neutralized by adding 2.16 parts of glacial acetic acid, and then poured into a large amount of water to precipitate a resin. The precipitated resin was filtered off. A resin (resin A1) having a weight average molecular weight of about 3.4 × 10 ³ is purified by repeating the reprecipitation operation of dissolving the filtered resin in acetone and then pouring it into a large amount of water for precipitation three times. 71 parts were obtained. Resin A1 has the following structural units.

Synthesis Example 2 [Synthesis of Resin A2]
A 4-necked flask equipped with a condenser and a stirrer was charged with 92.8 parts of 1,4-dioxane and 16.7 parts of monomer A, and the temperature was raised to 85 ° C. Thereto, 60.0 parts of p- (1-ethoxyethoxy) styrene, 39.0 parts of monomer A, 9.22 parts of monomer C, 4.06 parts of styrene, 26.6 parts of monomer D and 11.5 parts of azobisisobutyronitrile. Was dissolved dropwise in 138.5 parts of 1,4-dioxane over 1 hour. Thereafter, stirring was continued for 6 hours while maintaining 85 ° C. After the reaction solution was cooled to 40 ° C., a mixed solution of 1609 parts of methanol and 402 parts of water was sufficiently cooled, and the reaction solution was poured therein to precipitate a resin. The obtained resin was dissolved in methyl isobutyl ketone, and 3.09 parts of p-toluenesulfonic acid and 309.4 parts of water were added and stirred for 6 hours. The organic layer recovered by standing and liquid separation was washed with water about three times, and then the washed organic layer was poured into 2010 parts of n-heptane to precipitate a resin. The precipitated resin was collected by filtration and dried under reduced pressure to obtain 129 parts of a resin (resin A2) having a weight average molecular weight of 5.2 × 10 ³ . Resin A2 has the following structural units.

Synthesis Example 3 [Synthesis of Resin A3]
A four-necked flask equipped with a condenser and a stirrer was charged with 15.1 parts of 1,4-dioxane and heated to 85 ° C. Thereto 12.0 parts of p- (1-ethoxyethoxy) styrene, 4.65 parts of monomer B, 5.85 parts of monomer E, 1.39 parts of monomer F, 1.30 parts of styrene and 1.84 parts of azobisisobutyronitrile. A solution dissolved in 22.7 parts of 1,4-dioxane was added dropwise over 1 hour. Thereafter, stirring was continued for 6 hours while maintaining 85 ° C. After cooling the reaction solution to 40 ° C., a mixed solution of 262 parts of methanol and 65 parts of water was sufficiently cooled, and the reaction solution was poured into this to precipitate a resin. The obtained resin was dissolved in methyl isobutyl ketone, 0.50 parts of p-toluenesulfonic acid and 50.4 parts of water were added and stirred for 6 hours. The organic layer recovered by standing and liquid separation was washed with water about three times, and then the washed organic layer was poured into 327 parts of n-heptane to precipitate a resin. The precipitated resin was collected by filtration and dried under reduced pressure to obtain 18.1 parts of a resin (resin A3) having a weight average molecular weight of 4.9 × 10 ³ . Resin A3 has the following structural units.

Examples 1 to 10, Comparative Examples 1 and 2
(Preparation of resist composition)
Each component shown in Table 1 was mixed and dissolved, and further dissolved in a solvent described later, and then filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a resist composition.

＜樹脂＞
Ａ１：樹脂Ａ１
Ａ２：樹脂Ａ２
Ａ３：樹脂Ａ３
＜塩基性化合物（Ｃ）：クエンチャー＞
塩基性化合物Ｃ１：（東京化成工業（株）製）

＜溶剤＞
プロピレングリコールモノメチルエーテルアセテート ４００．０部
プロピレングリコールモノメチルエーテル １５０．０部
γ−ブチロラクトン ５．０部
＜化合物（Ｉ）＞
Ｉ−５：２，３，５−トリヨード安息香酸；東京化成工業（株）製

Ｉ−６：３−ヨード−４−メチル安息香酸；東京化成工業（株）製

Ｉ−１７：２-アミノ−５−ヨード安息香酸；東京化成工業（株）製

Ｉ−１２：２−ヨードフェニルメタノール；アルドリッチ社製

Ｉ−１５：２-ヨードフェノール；アルドリッチ社製

Ｘ１：１，２，４，５-テトラフルオロ−３，６−ジヨードベンゼン；アルドリッチ社製

<Acid generator (B)>
B1-11: synthesized by the method described in JP-A-2008-74843

<Resin>
A1: Resin A1
A2: Resin A2
A3: Resin A3
<Basic compound (C): quencher>
Basic compound C1: (manufactured by Tokyo Chemical Industry Co., Ltd.)

<Solvent>
Propylene glycol monomethyl ether acetate 400.0 parts Propylene glycol monomethyl ether 150.0 parts γ-butyrolactone 5.0 parts <Compound (I)>
I-5: 2,3,5-triiodobenzoic acid; manufactured by Tokyo Chemical Industry Co., Ltd.

I-6: 3-iodo-4-methylbenzoic acid; manufactured by Tokyo Chemical Industry Co., Ltd.

I-17: 2-amino-5-iodobenzoic acid; manufactured by Tokyo Chemical Industry Co., Ltd.

I-12: 2-iodophenylmethanol; manufactured by Aldrich

I-15: 2-iodophenol; manufactured by Aldrich

X1: 1,2,4,5-tetrafluoro-3,6-diiodobenzene; manufactured by Aldrich

(Production of resist pattern by electron beam exposure; evaluation as a resist composition for electron beam)
The silicon wafer was processed at 90 ° C. for 60 seconds using hexamethyldisilazane on a direct hot plate. This silicon wafer was spin-coated with a resist composition so that the film thickness of the composition layer was 0.04 μm. Thereafter, the composition layer was formed by pre-baking on a direct hot plate for 60 seconds at the temperature indicated in the “PB” column of Table 1. The composition layer formed on the wafer is directly drawn with a line and space pattern by using an electron beam drawing machine ["HL-800D 50keV" manufactured by Hitachi, Ltd. Exposed.
After exposure, post exposure bake on the hot plate at the temperature indicated in the “PEB” column of Table 1 for 60 seconds, followed by paddle development for 60 seconds with 2.38% tetramethylammonium hydroxide aqueous solution to form a resist pattern Got.
The obtained resist pattern (line and space pattern) was observed with a scanning electron microscope.

Line edge roughness evaluation (LER): The wall surface of a resist pattern produced by exposure with an exposure amount at which the space width and the line width of a 100 nm line-and-space pattern are 1: 1 is observed with a scanning electron microscope. The fluctuation width (unit: nm) of the unevenness on the side wall of the pattern was measured to obtain line edge roughness. The results are shown in Table 2.

(Production of resist pattern by EUV exposure; evaluation as a resist composition for EUV)
The silicon wafer was processed at 90 ° C. for 60 seconds using hexamethyldisilazane on a direct hot plate. This silicon wafer was spin-coated with the resist composition of Example 1 so that the film thickness of the composition layer was 0.04 μm.
Thereafter, the composition layer was formed by pre-baking on a direct hot plate for 60 seconds at the temperature indicated in the “PB” column of Table 1. The composition layer formed on the wafer was exposed to a line and space pattern using an EUV exposure machine while changing the exposure amount stepwise.
After exposure, post exposure bake on the hot plate at the temperature indicated in the “PEB” column of Table 1 for 60 seconds, followed by paddle development for 60 seconds with 2.38% tetramethylammonium hydroxide aqueous solution to form a resist pattern Got.

Line edge roughness evaluation (LER): The wall surface of a resist pattern produced by exposure with an exposure amount at which the space width and the line width of a 30 nm line-and-space pattern are 1: 1 is observed with a scanning electron microscope. The fluctuation width (unit: nm) of the unevenness on the side wall of the pattern was measured to obtain line edge roughness. The results are shown in Table 3.

  If this resist composition is used, a resist pattern having excellent line edge roughness (LER) can be produced. Therefore, this resist composition is extremely useful for fine processing of semiconductors and has high industrial value.

Claims (7)

Containing a compound represented by formula (I), a resin and an acid generator;
A resist composition, which is a resin in which the resin contains a structural unit represented by the formula (a1-0), is insoluble or hardly soluble in an alkaline aqueous solution, and becomes soluble in an alkaline aqueous solution by the action of an acid.

[In the formula (I),
z1 represents the integer of 1-4.
R ¹ represents a carboxy group, a hydroxy group, an aliphatic hydrocarbon group having a carboxy group or an aliphatic hydrocarbon group having a hydroxy group.
z2 represents an integer of 1 to 3. When z2 is 2 or more, the plurality of R ¹ are the same or different from each other.
A represents an aromatic hydrocarbon group having 6 to 20 carbon atoms which may have a substituent. ]

[In the formula (a1-0),
L ^aa represents an oxygen atom or ^* —O— (CH ₂ ) _g1 —CO—O— (g1 represents an integer of 1 to 7, and * represents a bond to a carbonyl group).
R ^ad represents a hydrogen atom or a methyl group.
R ^aa , R ^ab and R ^ac each independently represents an alkyl group having 1 to 8 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, or a combination thereof, or R ^aa and R ^ab Combine with each other to form a divalent hydrocarbon group having 2 to 20 carbon atoms. ] The resist composition according to claim 1, wherein the compound represented by formula (I) is a compound represented by formula (II).

[In the formula (II),
z3 represents an integer of 1 to 4.
R ¹ represents the same meaning as described above.
z4 represents an integer of 1 to 3. When z4 is 2 or more, the plurality of R ¹ are the same or different from each other.
R ² represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an amino group.
z5 represents 0 or 1.
However, z3 + z4 + z5 is 6 or less. ] The resist composition according to claim 1, wherein the structural unit represented by the formula (a1-0) is a structural unit represented by the formula (a1-1).

[In the formula (a1-1),
L ^a1 represents an oxygen atom or ^* —O— (CH ₂ ) _k1 —CO—O—, k1 represents an integer of 1 to 7, and * represents a bond with a carbonyl group.
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. ] The resist composition according to claim 1, wherein the acid generator is an acid generator represented by the formula (B1).

[In the formula (B1),
Q ¹ and Q ² each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group.
L ^b1 represents a 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 an alkyl group having 1 to 18 carbon atoms which may have a substituent or an alicyclic hydrocarbon group having 3 to 18 carbon atoms which may have a substituent. The methylene group constituting the alicyclic hydrocarbon group may be replaced with an oxygen atom, a sulfonyl group or a carbonyl group.
Z ⁺ represents an organic cation. ]   Furthermore, the resist composition as described in any one of Claims 1-4 containing a solvent. (1) The process of apply | coating the resist composition as described in any one of Claims 1-5 on a board | substrate,
(2) The process of drying the composition after application | coating and forming a composition layer,
(3) a step of exposing the composition layer;
(4) A method for producing a resist pattern, comprising a step of heating the composition layer after exposure, and (5) a step of developing the composition layer after heating.   The method for producing a resist pattern according to claim 6, wherein (3) is a step of exposing the composition layer to an electron beam or EUV.