JP2011052212A - Resin and resist composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin for a resist composition capable of preparing a resist pattern having an excellent line edge roughness and an excellent top shape. <P>SOLUTION: The resin is provided which has a structure unit originating in a compound expressed by formula (a1) wherein R<SP>a1</SP>represents a hydrogen atom, a halogen atom or an alkyl group, R<SP>a2</SP>represents a perfluoro adamantyl group, a monohydroxy-tetradecafluoro adamantyl group, a perfluoro cyclohexyl group or a monohydroxy-deca fluoro cyclohexyl group. L<SP>a1</SP>represents a single bond or an alicyclic hydrocarbon group, and L<SP>a2</SP>represents a single bond, an alkanediyl group or the like. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a resin having a structural unit derived from a fluorine-containing compound, a resist composition containing the resin, and a method for producing a resist pattern.

  Conventionally, various resist compositions have been proposed, for example, structural units derived from 2-ethyl-2-adamantyl methacrylate, 3-hydroxy-1-adamantyl methacrylate, and α-methacryloyloxy-γ-butyrolactone. And a resist composition containing the resin (see Patent Document 1 (see paragraphs [0088], [0092], and [Table 1])).

JP 2006-257078 A

  In conventional resins, defects may occur in a resist pattern obtained from a resist composition containing the resin, and line edge roughness and top shape may not always be satisfied.

The present invention includes the following inventions.
[1] A resin having a structural unit derived from the compound represented by the formula (a1).

[In the formula (a1), R ^a1 represents a hydrogen atom, a halogen atom, or a linear or branched C _1-6 alkyl group which may have a halogen atom. R ^a2 represents a perfluoroadamantyl group, a monohydroxy-tetradecafluoroadamantyl group, a perfluorocyclohexyl group, or a monohydroxy-decafluorocyclohexyl group. L ^a1 represents a divalent C _4-36 alicyclic hydrocarbon group which may have a single bond or a fluorine atom. L ^a2 represents a single bond or a linear or branched C _1-17 alkanediyl group, and the methylene group of the alkanediyl group is an oxygen atom (—O—) or a carbonyl group (—CO—). May be substituted. ]

[2] L ^a1 is a resin according to a single bond or a fluorine atom is also good adamantane-diyl group [1].

[3] Furthermore, it has a structural unit derived from at least one selected from the group consisting of a compound represented by the formula (a2-1) and a compound represented by the formula (a2-2) [1] or [2 ].

[In Formula (a2-1) and Formula (a2-2), L ^a3 and L ^a4 each independently represent an oxygen atom, a carbonyl group, —N (R ^a14 ) —, a linear or branched chain, A C _1-17 alkanediyl group or a combination thereof; R ^a14 represents a hydrogen atom or a linear or branched C _1-6 aliphatic hydrocarbon group; R ^a3 and R ^a4 each independently represents a hydrogen atom or a methyl group. R ^a7 represents a linear or branched C _1-6 aliphatic hydrocarbon group, and n1 represents an integer of 0-14. R ^a8 represents a linear or branched C _1-6 aliphatic hydrocarbon group or a linear or branched C _1-4 alkoxy group, and o1 is an integer of 0 to 10 Represents. However, n1 or o1 being 0 means that R ^a7 or R ^a8 does not exist, respectively, and when n1 or o1 is 2 or more, each of a plurality of R ^a7 or R ^a8 is the same or different from each other. May be. R ^a10 and R ^a11 each independently represent a linear or branched C _1-8 aliphatic hydrocarbon group or a C _3-10 alicyclic hydrocarbon group. ]

[4] A resist composition comprising the resin according to any one of [1] to [3] and an acid generator.

[5] The resist composition according to [4], further containing a basic compound.

[6] A step of applying a resist composition according to [4] or [5] onto a substrate to obtain a resist film;
A step of pre-baking the resist film;
Exposing the pre-baked resist film;
A step of post-exposure baking of the exposed resist film;
And a step of developing a post-exposure baked resist film with an alkali developer to obtain a resist pattern.

[7] A compound represented by formula (a1-3), formula (a1-4), formula (a1-6) or formula (a1-7).

  According to the resin of the present invention, a resist pattern having few defects, excellent line edge roughness, and excellent top shape can be obtained from a resist composition containing the resin.

<Compound (a1)>
The resin of the present invention has a structural unit derived from the compound represented by the formula (a1). First, the compound represented by formula (a1) will be described. Hereinafter, the “compound represented by the formula (a1)” may be abbreviated as “compound (a1)” or “monomer (a1)”. Similarly, compounds or monomers represented by other formulas may also be abbreviated. The chemical formula in this specification includes stereoisomerism. In the present specification, “C _xy ” means “the number of carbon atoms is x or more and y or less”.

[In the formula (a1), R ^a1 represents a hydrogen atom, a halogen atom, or a linear or branched C _1-6 alkyl group which may have a halogen atom. R ^a2 represents a perfluoroadamantyl group, a monohydroxy-tetradecafluoroadamantyl group, a perfluorocyclohexyl group, or a monohydroxy-decafluorocyclohexyl group. L ^a1 represents a divalent C _4-36 alicyclic hydrocarbon group which may have a single bond or a fluorine atom. L ^a2 represents a single bond or a linear or branched C _1-17 alkanediyl group, and the methylene group of the alkanediyl group is an oxygen atom (—O—) or a carbonyl group (—CO—). May be substituted. ]

The compound (a1) has an acrylate skeleton and easily undergoes radical polymerization to form a polymer (resin). Furthermore, since R ^a2 (and optionally L ^a1 ) of the compound (a1) is a fluorinated alicyclic hydrocarbon group, a fluorinated alicyclic hydrocarbon group can be introduced into the side chain of the resin. Resin with flexible main chain derived from acrylate skeleton and side chain of fluorine-containing alicyclic hydrocarbon group can suppress the occurrence of defects during immersion exposure, and also has excellent line edge roughness and top shape A resist pattern can be formed.

The compound (a1) is highly compatible with a (meth) acrylic monomer having an alicyclic hydrocarbon group or a lactone ring as described later, and can form a copolymer exhibiting good characteristics together with these. High compatibility with other monomers is also considered to be one of the reasons that good line edge roughness can be realized. In the present specification, "(meth) acrylic monomer", collectively a monomer having a structure of "CH ₂ = CH-CO-" or _{"CH 2 = C (CH 3)} -CO- ".

  Hereinafter, the structure of the compound (a1), that is, the group described in the formula (a1) will be described in order.

In the formula (a1), R ^a1 represents a hydrogen atom, a halogen atom, or a linear or branched C _1-6 alkyl group which may have a halogen atom. The halogen atom is preferably a fluorine atom. The number of carbon atoms of the alkyl group is preferably 4 or less, more preferably 2 or less. R ^a1 is preferably a hydrogen atom or a methyl group.

In the formula (a1), R ^a2 represents a perfluoroadamantyl group, a monohydroxy-tetradecafluoroadamantyl group, a perfluorocyclohexyl group, or a monohydroxy-decafluorocyclohexyl group.

L ^a1 represents a single bond or a divalent C _4-36 alicyclic hydrocarbon group. The divalent alicyclic hydrocarbon group may be monocyclic or polycyclic. Monocyclic alicyclic hydrocarbon groups include cycloalkanediyl groups (eg cyclopentanediyl group, cyclohexanediyl group, cycloheptanediyl group, cyclooctanediyl group) and cycloalkenediyl groups (eg cyclopentenediyl group, cyclohexenediyl group). Group, cycloheptenediyl group, cyclooctenediyl group) and the like. The polycyclic alicyclic hydrocarbon group includes a group obtained by hydrogenating a condensed aromatic hydrocarbon group (for example, hydronaphthalenediyl group), a bridged cyclic hydrocarbon group (for example, adamantanediyl group, norbornanediyl group, norbornene). Diyl group) and the like. In addition, a group having a shape in which a bridged ring (for example, norbornane ring) and a single ring (for example, cycloheptane ring or cyclohexane ring) or a polycycle (for example, decahydronaphthalene ring) are condensed, or group fused shapes also included in the divalent alicyclic hydrocarbon group having L ^a1.

Divalent alicyclic hydrocarbon group L ^a1 may have a fluorine atom. The divalent alicyclic hydrocarbon group represented by L ^a1 is preferably one in which one or more hydrogen atoms, more preferably two or more hydrogen atoms, more preferably all hydrogen atoms are substituted with fluorine atoms. . L ^a1 is preferably an adamantanediyl group which may have a single bond or a fluorine atom. Of the adamantanediyl groups, perfluoroadamantanediyl groups are preferred.

In the formula (a1), L ^a2 represents a single bond or a linear or branched C _1-17 (preferably C _1-8 ) alkanediyl group. The methylene group of the alkanediyl group may be substituted with an oxygen atom or a carbonyl group. When L ^a1 is a single bond, L ^a2 is preferably a single bond, — (CH ₂ ) _m1 —, or — (CH ₂ ) _m1 —CO—O—; L ^a1 is a divalent alicyclic ring When it is a hydrocarbon group, L ^a2 is preferably —O— (CH ₂ ) _m1 — or —O— (CH ₂ ) _m1 —O—; m1 is an integer from 1 to 4, preferably 1. Or 2.

Among the compounds (a1), at least one of L ^a1 and R ^a2 has an adamantane skeleton, and R ^a2 is a perfluoroadamantyl group, a monohydroxy-tetradecafluoroadamantyl group, a perfluorocyclohexyl group, or a monohydroxy-decafluorocyclo Compounds that are xyl groups are preferred. Preferred combinations of L ^a1 and R ^a2 are (1) L ^a1 : single bond, R ^a2 : perfluoroadamantyl group, (2) L ^a1 : adamantanediyl group, R ^a2 : perfluoroadamantyl group or perfluorocyclohexyl group, (3) L ^{a1 is a} perfluoroadamantanediyl group, R ^{a2 is a} perfluoroadamantyl group or a perfluorocyclohexyl group. In addition, in the perfluoroadamantyl group and the perfluorocyclohexyl group in the above (1) to (3), one of the fluorine atoms may be substituted with a hydroxy group.

  The compound (a1) is preferably a compound represented by any one of the formulas (a1-1) to (a1-7), more preferably the formula (a1-3), the formula (a1-4), and the formula It is a compound represented by (a1-6) or formula (a1-7).

Compound (a1) can be produced by an esterification reaction between an acid halide: CH ₂ ═CH (R ^a1 ) —COX ^a1 and an alcohol: HO—L ^a1 —L ^a2 —R ^a2 (wherein X ^a1 is A halogen atom, preferably Cl, wherein R ^a1 , R ^a2 , L ^a1 and L ^a2 are as defined above. Carboxylic acid: CH ₂ ═CH (R ^a1 ) —COOH may be used in place of the acid halide.

  The esterification reaction using alcohol is usually about 20 to 200 ° C. (preferably 50 to 150) with stirring in an aprotic solvent such as dichloroethane, toluene, ethylbenzene, monochlorobenzene, acetonitrile, N, N-dimethylformamide and the like. It may be performed in a temperature range of about ℃.

  In the esterification reaction using alcohol, an acid catalyst may be used. Examples of the acid catalyst include organic acids such as p-toluenesulfonic acid and inorganic acids such as sulfuric acid. Although an acid catalyst may be used in excess, it is usually about 0.001 to 5 moles per mole of carboxylic acid.

  In order to shorten the reaction time, an esterification reaction using alcohol may be performed while dehydrating using a Dean Stark apparatus or the like. Furthermore, in the esterification reaction using alcohol, a dehydrating agent may be added. Examples of the dehydrating agent include dicyclohexylcarbodiimide; 1-alkyl-2-halopyridinium salt; 1,1′-carbonyldiimidazole; bis (2-oxo-3-oxazolidinyl) phosphine chloride; 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride; di-2-pyridyl carbonate; di-2-pyridylthiono carbonate; 6-methyl-2-nitrobenzoic anhydride in the presence of 4- (dimethylamino) pyridine; Etc. Although the dehydrating agent may be used in excess, the amount is usually about 0.5 to 5 mol, preferably about 1 to 3 mol, per 1 mol of carboxylic acid.

Compound (a1) can be produced by an esterification reaction between a carboxylate salt: CH ₂ ═CH (R ^a1 ) —COOM and an alkyl halide: X—L ^a1 —L ^a2 —R ^a2 (wherein M is Represents an alkali metal, X represents a halogen, and R ^a1 , R ^a2 , L ^a1 and L ^a2 are as defined above.

  As M, Cs, K and Na showing high reactivity are preferable, and K and Na which are easily available are more preferable. X is preferably I, Br, or Cl in consideration of reactivity and availability. The reaction between the carboxylate and the alkyl halide may be performed in the presence of an alkali metal iodide.

  The esterification reaction using an alkyl halide is usually performed in a temperature range of about 50 to 150 ° C. while stirring in an aprotic polar solvent such as N, N-dimethylformamide or dimethyl sulfoxide.

  The compound (a1) obtained by the esterification reaction can be purified by liquid separation or a column.

<resin>
The resin of the present invention is obtained by polymerizing one or more compounds (a1). The resin of the present invention is preferably a copolymer of the compound (a1) and another monomer. However, the resin of the present invention may be a homopolymer only of the compound (a1). The total amount of the compound (a1) used in the polymerization is preferably 0.1 mol% or more (more preferably 0.2 mol% or more, further preferably 0.5 mol% or more) with respect to the total number of moles of monomers. , Preferably 10 mol% or less (more preferably 8 mol% or less, still more preferably 6 mol% or less).
In addition, the resin of this invention may mix the polymer containing a compound (a1), and another polymer. In this case, the content of the structural unit derived from the compound (a1) in the resin is preferably 0.1 mol% or more (more preferably 0.2 mol% or more, more preferably 0.5 mol%) in all units of the resin. Mol% or more), preferably 10 mol% or less (more preferably 8 mol% or less, still more preferably 6 mol% or less).

  The polymerization is usually radical polymerization. The radical polymerization is usually performed at 0 to 150 ° C. (preferably 40 to 100) while stirring in a solvent of dioxane, toluene, tetrahydrofuran, methyl isobutyl ketone, isopropyl alcohol, γ-butyrolactone, propylene glycol monomethyl ether acetate and ethyl lactate. It may be performed in a temperature range of about ° C. Examples of the polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylvaleronitrile), 1 , 1′-azobis (cyclohexane-1-carbonitrile), dimethyl-2,2′-azobis (2-methylpropionate) and the like can be used in the polymerization field. A polymerization initiator may be used individually by 1 type, and may use 2 or more types together. The total amount of the polymerization initiator is preferably about 0.01 to 10 mol% (more preferably about 0.1 to 5 mol%) based on the total number of moles of monomers.

  For radical polymerization, one or more chain transfer agents may be used. As the chain transfer agent, those known in the polymerization field such as thiol and disulfide can be used. The total amount used is preferably about 0.01 to 10 mol% (more preferably about 0.1 to 5 mol%) with respect to the total number of moles of monomers.

  The weight average molecular weight of the resin of the present invention obtained as described above is preferably 2,500 or more (more preferably 3,000 or more), preferably 100,000 or less (more preferably 50,000 or less). .

  The resin of the present invention is preferably a resin that becomes alkali-soluble by the action of an acid (hereinafter sometimes abbreviated as “resin (A)”). Note that “becomes soluble in an alkali by the action of an acid” means “insoluble or hardly soluble in an aqueous alkali solution before contact with an acid but becomes soluble in an aqueous alkali solution after contact with an acid”. To do. The resin (A) can be synthesized by copolymerizing the compound (a1) and a monomer that becomes alkali-soluble by the action of an acid.

The resin (A) is preferably a (meth) acrylic monomer (a2) (hereinafter referred to as “acid-capable”) which becomes alkali-soluble by the action of the compound (a1) and an acid and has a C _5-20 alicyclic hydrocarbon group. And a copolymer with a solubilized monomer (a2) ”. More preferable resin (A) is at least compound (a1), acid-solubilizing monomer (a2), (meth) acrylic monomer (a3) having a hydroxy group-containing adamantyl group (hereinafter referred to as “hydroxyadamantyl monomer (a3)”) And a copolymer obtained by polymerizing a (meth) acrylic monomer (a4) having a lactone ring (hereinafter abbreviated as “lactone type monomer (a4)”). The hydroxyadamantyl monomer (a3) may have a group (for example, an alkylcarbonyloxy group) that forms a hydroxy group by the action of an acid instead of the hydroxy group.

  In this specification, “(meth) acrylate” and “(meth) acrylic acid” collectively refer to “acrylate or methacrylate” and “acrylic acid or methacrylic acid”, respectively. Below, each monomer other than a compound (a1) is demonstrated in order.

<Acid solubilizing monomer (a2)>
Examples of the alicyclic hydrocarbon group of the acid solubilizing monomer (a2) include the alicyclic hydrocarbon group described in R ^a1 of the compound (a1). Among these, an adamantyl group, a cyclohexyl group, a cycloheptyl group, and a norbornyl group (including a group having a shape in which two or more norbornyl rings are condensed) are preferable.

  The acid-solubilizing monomer (a2) is preferably a monomer having an alicyclic hydrocarbon group whose bonding position is a tertiary carbon atom (excluding the bridge-head carbon atom of the bridged cyclic hydrocarbon group), more preferably A compound represented by any one of formula (a2-1) to formula (a2-4), more preferably a compound represented by formula (a2-1) or formula (a2-2). These may be used alone or in combination of two or more.

In the above formula, each of L ^{a3 to} L ^a6 independently represents an oxygen atom, a carbonyl group, —N (R ^a14 ) —, a linear or branched C _1-17 alkanediyl group, or a combination thereof. R ^a14 represents a hydrogen atom or a linear or branched C _1-6 aliphatic hydrocarbon group. R ^{a3 to} R ^a6 each independently represents a hydrogen atom or a methyl group. R ^a7 represents a linear or branched C _1-6 aliphatic hydrocarbon group, and n1 represents an integer of 0-14. R ^a8 and R ^a9 each independently represent a linear or branched C _1-6 aliphatic hydrocarbon group, or a linear or branched C _1-4 alkoxy group, and o1 And p1 each independently represents an integer of 0 to 10. However, n1, o1 or p1 being 0 means that R ^a7 , R ^a8 or R ^a9 does not exist, respectively, and when n1, o1 or p1 is 2 or more, a plurality of R ^a7 , R 1, respectively. ^a8 or R ^a9 may be the same as or different from each other. R ^{a10 to} R ^a12 each independently represents a linear or branched C _1-8 aliphatic hydrocarbon group or a C _3-10 alicyclic hydrocarbon group. R ^a13 represents a norbornyl group or a condensed norbornyl group represented by the following formula. Hereinafter, “norbornyl group and condensed norbornyl group” may be abbreviated as “(condensed) norbornyl group”.

In the above formula, R ^a15 represents a linear or branched C _1-8 aliphatic hydrocarbon group or a C _3-10 alicyclic hydrocarbon group. R ^a16 and R ^a17 each independently represent a hydrogen atom or a C _1-8 aliphatic hydrocarbon group that may contain a hetero atom; or R ^a16 and R ^a17 are bonded to each other to form a hydrocarbon A ring or a heterocyclic ring may be formed, or a double bond may be formed between the carbon atom to which R ^a16 is bonded and the carbon atom to which R ^a17 is bonded.

When L ^{a3 to} L ^a6 are a combination of a C _1-17 alkanediyl group and an oxygen atom, the number of atoms constituting the main chain is preferably 17 or less. When an adamantyl group, a cyclohexyl group, a cycloheptyl group, or a (condensed) norbornyl group is expressed as Ad in order to indicate the bonding direction, the combined shape L ^{a3 to} L ^a6 may be, for example, —O—C _1-16 alkanediyl -Ad, -C _1-16 alkanediyl-O-Ad, -C _k1 alkanediyl-O-C _j1 alkanediyl-Ad (wherein 1≤k1, 1≤j1, k1 + j1≤16, and so on);
-CO-C _1-16 alkanediyl -Ad, -C _1-16 alkanediyl -CO-Ad, -C _k1 alkanediyl -CO-C _j1 alkanediyl -Ad;
-N (R ^a14 ) -C _1-16 alkanediyl-Ad, -C _1-16 alkanediyl-N (R ^a14 ) -Ad, -C _k1 alkanediyl-N (R ^a14 ) -C _j1 alkanediyl-Ad ;
-CO-O-Ad, -CO-O-C _1-15 alkanediyl-Ad, -C _1-15 alkanediyl-CO-O-Ad, -C _i1 alkanediyl-CO-O- _Ch1 alkanediyl- Ad (wherein 1 ≦ i1, 1 ≦ h1, i1 + h1 ≦ 15, and so on);
-O-CO-Ad, -O-CO-C _1-15 alkanediyl-Ad, -C _1-15 alkanediyl-O-CO-Ad, -C _i1 alkanediyl-O-CO- _Ch1 alkanediyl- Ad;
-CO-O-C _1-14 alkanediyl-O-Ad, -CO-O-C _1-13 alkanediyl-CO-O-Ad;
Etc.

Preferred L ^{a3 to} L ^a6 are —O—Ad, —O— (CH ₂ ) _g1 —CO—O—Ad, —N (R ^a19 ) — (CH ₂ ) _g1 —CO—O—Ad (described above) In the formula, g1 is 1 to 7, more preferably 1 to 4, and still more preferably 1. R ^a19 is a hydrogen atom, a methyl group, or an ethyl group. With such L ^{a3 to} L ^a6 , the compound (a2-1) to compound (a2-4) are such that the tertiary carbon atom of the alicyclic hydrocarbon group is a carbonyloxy group (—CO—O—). This corresponds to an ester having a structure bonded to an oxygen atom, that is, an ester having a tertiary alcohol residue. A resin containing an ester having a tertiary alcohol residue as a structural unit is preferable because it is easily cleaved by the catalytic action of an acid generated from an acid generator and the solubility in a developer (alkaline aqueous solution) is improved.

R ^{a3 to} R ^a6 are preferably methyl groups. R ^{a7 to} R ^a9 are each independently preferably a C _1-4 aliphatic hydrocarbon group, more preferably a methyl group; n1 to p1 are each independently preferably an integer of 0 to 3, more preferably Is 0 or 1.

The carbon number of the aliphatic hydrocarbon group of R ^{a10 to} R ^a12 and R ^a15 is preferably 6 or less, and the carbon number of the alicyclic hydrocarbon group is preferably 8 or less, more preferably 6 or less. Examples of the linear or branched aliphatic hydrocarbon group include a methyl group, an ethyl group, a 1-methylethyl group (i-propyl group), and a 1,1-dimethylethyl group (tert-butyl group). 2,2-dimethylethyl group, propyl group, 1-methylpropyl group, 2,2-dimethylpropyl group, 1-ethylpropyl group, butyl group, 1-methylbutyl group, 2-methylbutyl group, 3-methylbutyl group, Examples include 1-propylbutyl group, pentyl group, 1-methylpentyl group, hexyl group, 1,4-dimethylhexyl group, heptyl group, 1-methylheptyl group, octyl group and the like. Examples of the alicyclic hydrocarbon group include a cycloheptyl group, a methylcycloheptyl group, a cyclohexyl group, a methylcyclohexyl group, a dimethylcyclohexyl group, a norbornyl group, and a methylnorbornyl group.

R ^a13 is preferably a norbornyl group having one norbornane ring, and R ^a16 and R ^a17 are preferably hydrogen atoms.

  Examples of the acid solubilizing monomer (a2-1) having an adamantyl group include the following.

  Examples of the acid-solubilizing monomer (a2-2) having a cyclohexyl group include the following.

  Examples of the acid solubilizing monomer (a2-3) having a cycloheptyl group include the following.

  Examples of the acid-solubilizing monomer (a2-4) having a (condensed) norbornyl group include the following.

  Among the acid solubilizing monomers (a2), a monomer (a2-1) having an adamantyl group and a monomer (a2-2) having a cyclohexyl group are preferable. 1-ethyl-1-cyclohexyl (meth) acrylate, 2-ethyl-2-adamantyl (meth) acrylate, 2-isopropyl-2-adamantyl (meth) acrylate, 2-methyl-2- (meth) acrylate Adamantyl and 1- (2-methyl-2-adamantyloxycarbonyl) methyl methacrylate (particularly in the form of methacrylate) are more preferred because they improve the sensitivity of the resist composition and the heat resistance of the resist film.

  The content of the structural unit derived from the acid-solubilizing monomer (a2) in the resin is preferably 10 mol% or more (more preferably 20 mol% or more, more preferably 30 mol% or more), preferably in the total unit of the resin. Is 70 mol% or less (more preferably 60 mol% or less, still more preferably 50 mol% or less).

<Hydroxyadamantyl monomer (a3)>
The hydroxyadamantyl monomer (a3) may have a hydroxy-containing substituent such as a hydroxymethyl group (—CH ₂ OH) on the adamantane ring, but the hydroxy group (—OH) itself is present on the adamantane ring. It is preferable to have. The number of hydroxy groups may be one or two or more.

  The hydroxyadamantyl monomer (a3) is preferably represented by the formula (a3-1). A monomer (a3-1) may be used individually by 1 type, and may use 2 or more types together.

In formula (a3-1), L ^a7 represents an oxygen atom, a carbonyl group, —N (R ^a24 ) —, a linear or branched C _1-17 alkanediyl group, or a combination thereof; R ^a24 represents a hydrogen atom or a linear or branched C _1-6 aliphatic hydrocarbon group. R ^a20 represents a hydrogen atom or a methyl group. R ^a21 represents a hydroxy group or a group that forms a hydroxy group by the action of an acid. R ^a22 and R ^a23 each independently represent a hydrogen atom, a methyl group, a hydroxy group, or a group that forms a hydroxy group by the action of an acid. q1 represents the integer of 0-10. However, q1 being 0 means that no methyl group is present.

The group that forms a hydroxy group by the action of an acid of R ^{a21 to} R ^a23 is not particularly limited as long as it has a structure of —O—C and can be hydrolyzed to form a hydroxy group by the action of an acid. No. Examples of such a group include an alkoxy group (—O—R), an alkylcarbonyloxy group (—O—CO—R), an alkyloxycarbonyloxy group (—O—CO—O—R) and the like (described above). In the formula, R represents an alkyl group).

The description of L ^a7 is the same as L ^{a3 to} L ^a6 . Preferred R ^a20 is a methyl group. Preferred R ^a21 is a hydroxy group. Preferred R ^a22 is a hydrogen atom. Preferred R ^a23 is a hydrogen atom or a hydroxy group. q1 is preferably an integer of 0 to 3, more preferably 0 or 1.

  Examples of the hydroxyadamantyl monomer (a3-1) include the following.

  Among the hydroxyadamantyl monomers (a3-1), 3-hydroxy-1-adamantyl (meth) acrylate, 3,5-dihydroxy-1-adamantyl (meth) acrylate, 1- (3-hydroxy-1 methacrylate) -Adamantyloxycarbonyl) methyl and 1- (3,5-dihydroxy-1-adamantyloxycarbonyl) methyl methacrylate are preferred, and those in the form of methacrylate are more preferred.

  The content of the structural unit derived from the hydroxyadamantyl-type monomer (a3) in the resin is preferably 3 mol% or more (more preferably 4 mol% or more, more preferably 5 mol% or more), preferably in all units of the resin. Is 30 mol% or less (more preferably 20 mol% or less, still more preferably 10 mol% or less).

<Lactone type monomer (a4)>
The lactone ring contained in the lactone type monomer (a4) may be a single ring such as a β-propiolactone ring, γ-butyrolactone ring, or δ-valerolactone ring. It may be a condensed ring with an alkane ring or a norbornane ring. Preferred lactone rings are γ-butyrolactone rings and condensed rings of γ-butyrolactone rings and other rings as shown below.

  The lactone type monomer (a4) is preferably represented by the formula (a4-1), the formula (a4-2) or the formula (a4-3). These may be used alone or in combination of two or more.

In formulas (a4-1) to (a4-3), L ^{a8 to} L ^a10 each independently represent an oxygen atom, a carbonyl group, —N (R ^a31 ) —, linear or branched C _1-17 represents an alkanediyl group or a combination thereof, and R ^a31 represents a hydrogen atom or a linear or branched C _1-6 aliphatic hydrocarbon group. R ^{a25 to} R ^a27 each independently represent a hydrogen atom or a methyl group. R ^a28 represents a C _1-4 aliphatic hydrocarbon group, and r1 represents an integer of 0 to 5. R ^a29 and R ^a30 each independently represent a carboxy group, a cyano group or a C _1-4 aliphatic hydrocarbon group, and s1 and t1 each independently represent an integer of 0 to 3. However, r1, s1, or t1 being 0 means that R ^a28 , R ^a29, or R ^a30 does not exist, respectively, and when r1, s1, or t1 is 2 or more, a plurality of R ^a28 , R 1, respectively. ^{Either a29} or R ^a30 may be the same as or different from each other.

The explanation of L ^{a8 to} L ^a10 is the same as that of L ^{a3 to} L ^a6 . Preferred R ^{a25 to} R ^a27 are methyl groups. Preferred R ^a28 is a methyl group. R ^a29 and R ^a30 are each independently preferably a carboxy group, a cyano group or a methyl group. r1, s1, or t1 is preferably independently 0 to 2, more preferably 0 or 1.

  Examples of the lactone monomer (a4-1) having a γ-butyrolactone ring include the following.

  Examples of the lactone type monomer (a4-2) having a condensed ring of γ-butyrolactone ring and norbornane ring include the following.

  Examples of the lactone type monomer (a4-3) having a condensed ring of γ-butyrolactone ring and cyclohexane ring include the following.

Among lactone type monomers (a4), (meth) acrylic acid (5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yl, (meth) acrylic acid tetrahydro-2 -Oxo-3-furyl and (meth) acrylic acid 2- (5-oxo-4-oxatricyclo [4.2.1.0 ^3,7 ] nonan-2-yloxy) -2-oxoethyl are preferred, A methacrylate form is more preferable.

  The content of the structural unit derived from the lactone type monomer (a4) in the resin is preferably 25 mol% or more (more preferably 35 mol% or more, more preferably 45 mol% or more), preferably in the total unit of the resin. It is 75 mol% or less (more preferably 65 mol% or less, still more preferably 55 mol% or less).

<Other monomers>
<Monomer (a5)>
The resin (A) may have a structural unit derived from another monomer. Other monomers include maleic anhydride represented by formula (a5-1), itaconic anhydride represented by formula (a5-2), norbornene represented by formula (a5-3), and the like. The compound which has a polymerizable carbon-carbon double bond is mentioned.

Wherein (A5-3), R ^a34 and R ^a35 are each independently a hydrogen atom, a substituent (e.g. hydroxy groups) which may have a C _1-3 aliphatic hydrocarbon group, a cyano group, a carboxy Group or an alkoxycarbonyl group (—COOR ^a36 ). Provided that when both R ^a34 and R ^a35 is a carboxy group, bonded R ^a34 and R ^a35 each other, may form a carboxylic acid anhydride. R ^a36 represents a linear or branched C _1-8 aliphatic hydrocarbon group or a C _4-36 alicyclic hydrocarbon group; the methylene group of the alicyclic hydrocarbon group is an oxygen atom Alternatively, it may be substituted with a carboxy group.

Examples of the aliphatic hydrocarbon group of R ^a34 and R ^a35, for example a methyl group, an ethyl group, a propyl group, a hydroxymethyl group, 2-hydroxyethyl group, and -COOR ^a36. Examples of R ^a36 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.

  Examples of norbornene (a5-3) include 2-norbornene, 2-hydroxy-5-norbornene, 5-norbornene-2-carboxylic acid, methyl 5-norbornene-2-carboxylate, 5-norbornene-2-carboxylic acid 2 -Hydroxy-1-ethyl, 5-norbornene-2-methanol, 5-norbornene-2,3-dicarboxylic acid anhydride and the like.

Acid labile group, for example, norbornene having an alkoxycarbonyl group -COOR ^a36 oxy group (-O-) is bonded to the tertiary carbon atoms (excluding the bridgehead carbon atoms bridged cyclic hydrocarbon group) (A5- 3) (that is, an ester having a tertiary alcohol residue) can be easily cleaved with an acid despite having a bulky norbornene ring structure to improve the solubility of the copolymer. Examples of norbornene (a5-3) having an acid labile group include 5-norbornene-2-carboxylic acid-t-butyl, 5-norbornene-2-carboxylic acid 1-cyclohexyl-1-methylethyl, 5 -1-methylcyclohexyl norbornene-2-carboxylate, 2-methyl-2-adamantyl 5-norbornene-2-carboxylate, 2-ethyl-2-adamantyl 5-norbornene-2-carboxylate, 5-norbornene-2- Carboxylic acid 1- (4-methylcyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1- (4-hydroxycyclohexyl) -1-methylethyl, 5-norbornene-2-carboxylic acid 1-methyl- 1- (4-oxocyclohexyl) ethyl, 5-norbornene-2-carboxylic acid 1- (1-adama Chill) -1-methylethyl and the like.

<Monomer (a6)>
As another monomer, a monomer having a group represented by the following formula (3) and a polymerizable double bond group (preferably a group having a carbon-carbon double bond, more preferably a (meth) acryloyl group) ( a6).

[In the formula (3), Ra ³⁷ represents a fluorinated alkyl group having 1 to 6 carbon atoms. ]

Examples of the fluorinated alkyl group for Ra ³⁷ include a difluoromethyl group, a perfluoromethyl group, a 1,1-difluoroethyl group, a 2,2-difluoroethyl group, a 2,2,2-trifluoroethyl group, and a perfluoro group. Ethyl group, 1,1,2,2-tetrafluoropropyl group, 1,1,2,2,3,3-hexafluoropropyl group, perfluoroethylmethyl group, 1- (trifluoromethyl) -1,2 , 2,2-tetrafluoroethyl group, perfluoropropyl group, 1,1,2,2-tetrafluorobutyl group, 1,1,2,2,3,3-hexafluorobutyl group, 1,1,2 , 2,3,3,4,4-octafluorobutyl group, perfluorobutyl group, 1,1-bis (trifluoro) methyl-2,2,2-trifluoroethyl group, 2- (perfluoropro E) Ethyl group, 1,1,2,2,3,3,4,4-octafluoropentyl group, 1,1,2,2,3,3,4,4,5,5-decafluoropentyl group 1,1-bis (trifluoromethyl) -2,2,3,3,3-pentafluoropropyl group, perfluoropentyl group, 2- (perfluorobutyl) ethyl group, 1,1,2,2, 3,3,4,4,5,5-decafluorohexyl group, 1,1,2,2,3,3,4,4,5,5,6,6-dodecafluorohexyl group, perfluoropentylmethyl Groups and perfluorohexyl groups.

The fluorinated alkyl group of Ra ³⁷ preferably has 1 to 4 carbon atoms, more preferably a perfluoromethyl group, a perfluoroethyl group, and a perfluoropropyl group, and particularly preferably a perfluoromethyl group.

  As a monomer (a6) which has group represented by Formula (3), what is represented by the following formula | equation (a6-1)-Formula (a6-5) is mentioned, for example. Among these, what is represented by Formula (a6-1) is preferable.

In the above formula, R ^a37 is the same as described above. R ^{a38 to} R ^a41 each independently represents a hydrogen atom or a methyl group. L ^{a11 to} L ^a15 each independently represents a single bond or a linear or branched C _1-4 alkanediyl group.

^Examples of the alkanediyl group represented by L ^{a11 to} L ^a15 include a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, and a butane-1,3. -A diyl group, a dimethylmethylene group, etc. are mentioned.

  As a monomer (a6-1), the following are mentioned, for example.

  As a monomer (a6-2), the following are mentioned, for example.

  As a monomer (a6-3), the following are mentioned, for example.

  As a monomer (a6-4), the following are mentioned, for example.

  As a monomer (a6-5), the following are mentioned, for example.

  The content of the structural unit derived from the other monomer (a5) and monomer (a6) in the resin is preferably 0.3 mol% or more (more preferably 0.5 mol% or more, even more preferably) in all units of the resin. Is 1 mol% or more), preferably 15 mol% or less (more preferably 10 mol% or less, still more preferably 5 mol% or less).

<Resist composition>
The present invention also provides a resist composition containing a resin having a structural unit derived from the compound (a1) (preferably a resin (A) that becomes alkali-soluble by the action of an acid) and an acid generator. The resist composition of the present invention is suitable as a chemically amplified positive resist composition for immersion exposure. A general chemically amplified positive resist composition usually contains an acid generator (B) and a solvent (D) in addition to a resin that becomes alkali-soluble by the action of an acid, and in some cases, a basic compound ( C). Hereinafter, each of these components will be described in order.

<Acid generator (B)>
In the resist composition of the present invention, the acid generator (B) (preferably a photoacid generator) is preferably 1 part by mass or more (preferably 3 parts by mass or more), preferably 20 parts per 100 parts by mass of the resin. It is contained in an amount of not more than part by mass (more preferably not more than 15 parts by mass, still more preferably not more than 10 parts by mass).

Acid generators are classified into nonionic systems (for example, organic halides, sulfonate esters, sulfones, etc.) and ionic systems, with ionic systems being preferred. Ionic acid generators include those having inorganic anions (for example, BF ₄ ⁻ , PF ₆ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ ) and those having organic anions (for example, sulfonate anion, bissulfonylamine anion). Among them, those having a sulfonate anion are preferable. The acid generator (B) is preferably a sulfonate represented by the formula (B1).

In formula (B1), Q ¹ and Q ² each independently represent a fluorine atom or a C _1-6 perfluoroalkyl group. L ^b1 is selected from the group consisting of a single bond, an oxygen atom, a carbonyl group, a linear or branched C _1-17 alkanediyl group, or an oxygen atom, a carbonyl group, and a C _1-17 alkanediyl group. Two or more combinations are represented. Y represents a _C3-36 alicyclic hydrocarbon group which may have a substituent, and the methylene group contained in the alicyclic hydrocarbon group may be substituted with an oxygen atom or a carbonyl group. Good. Z ⁺ represents an organic cation.

Examples of the C _1-6 perfluoroalkyl group for Q ¹ and Q ² include a perfluoromethyl group, a perfluoroethyl group, a perfluoro-n-propyl group, a perfluoroisopropyl group, a perfluoro-n-butyl group, a perfluoro-sec-butyl group, Examples include a perfluoro-tert-butyl group, a perfluoro-n-pentyl group, and a perfluoro-n-hexyl group. Q ¹ and Q ² are preferably a perfluoromethyl group and a fluorine atom, and more preferably a fluorine atom.

  Examples of the alicyclic hydrocarbon group for Y include those described above, and among them, an adamantyl group which may have a substituent and an oxoadamantyl group which may have a substituent are preferable.

Examples of the substituent for Y include a halogen atom, a hydroxy group, a linear or branched C _1-12 aliphatic hydrocarbon group, a C _3-12 alicyclic hydrocarbon group, and a hydroxy group-containing C _{1- 12} aliphatic hydrocarbon group, C _1-12 alkoxy group, C _6-20 aromatic hydrocarbon group, C _7-21 aralkyl group, C _2-4 acyl group, glycidoxy group, or — (CH ₂ ) _m2 —O —CO—R ^b1 group (wherein R ^b1 is a linear or branched C _1-16 aliphatic hydrocarbon group, C _3-16 alicyclic hydrocarbon group, or C _6-20 aromatic M2 represents an integer of 0 to 4, provided that m2 is 0 means that no methylene group is present. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Examples of the linear or branched aliphatic hydrocarbon group or alicyclic hydrocarbon group include those described for the resin (A). Examples of the hydroxy group-containing aliphatic hydrocarbon group include a hydroxymethyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, and a butoxy group. Examples of the aromatic hydrocarbon group include a phenyl group, a naphthyl group, an antonyl group, a p-methylphenyl group, a p-tert-butylphenyl group, and a p-adamantylphenyl group. Examples of the aralkyl group include benzyl group, phenethyl group, phenylpropyl group, trityl group, naphthylmethyl group, naphthylethyl group, and the like. Examples of the acyl group include an acetyl group, a propionyl group, and a butyryl group. The plurality of substituents may be the same as or different from each other.

  Examples of the alicyclic hydrocarbon group include those represented by the formula (W1) to the formula (W24). Among these, Formula (W11) (adamantane ring), Formula (W14) (2-oxoadamantane ring), Formula (W15) (γ-butyrolactone ring) and Formula (W19) (condensation of γ-butyrolactone ring and norbornane ring) Ring) is preferable, and Formula (W11) and Formula (W14) are more preferable.

  Examples of the alicyclic hydrocarbon group having an aliphatic hydrocarbon group include the following.

  Examples of the alicyclic hydrocarbon group having a hydroxy group or a hydroxy group-containing aliphatic hydrocarbon group include the following.

  Examples of the alicyclic hydrocarbon group having an aromatic hydrocarbon group include the following.

Examples of the alicyclic hydrocarbon group having a — (CH ₂ ) _m2 —O—CO—R ^b1 group include the following.

As the alkanediyl group of L ^b1 , a methylene group, an ethylene group, a propane-1,3-diyl group, a propane-1,2-diyl group, a butane-1,4-diyl group, a butane-1,3-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, Examples include a hexadecane-1,16-diyl group and a heptadecane-1,17-diyl group.

The alkanediyl group of L ^b1 is a linear or branched aliphatic hydrocarbon group or an alicyclic hydrocarbon group (preferably a linear or branched C _1-4 aliphatic hydrocarbon group. ) Side chain. Examples of the side chain of the alkanediyl group 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, an n-pentyl group, an n-hexyl group, and a heptyl group. Octyl group, 2-ethylhexyl group, nonyl group, decyl group, undecyl group, dodecyl group and the like.

L ^b1 may be a combination of two or more selected from the group consisting of an oxygen atom, a carbonyl group and a C _1-17 alkanediyl group. Examples of such combinations include those described for L ^{a1 to} L ^a4 .

L ^b1 is preferably any one of the connecting parts represented by the formulas (b1-1) to (b1-4). In formulas (b1-1) to (b1-4), Y is also shown to indicate the direction of coupling.

In formula (b1-1) to formula (b1-4), L ^b2 represents a single bond or a linear or branched C _1-15 alkanediyl group. L ^b3 represents a single bond, a linear or branched C _1-15 alkanediyl group, or a combination of a linear or branched C _1-15 alkanediyl group and an oxygen atom. L ^{b4 to} L ^b7 each independently represent a linear or branched C _1-15 alkanediyl group. The carbon number of the alkanediyl group of L ^{b2 to} L ^b7 is preferably 1 to 6, more preferably 1 to 4, and further preferably 1 or 2. Among these, the connecting portion (b1-1) is preferable, connecting portion L ^b2 is a single bond or a methylene group (b1-1) is preferable.

  Among the sulfonate anions having the connecting portion (b1-1), those represented by the formula (b1-1-1) to the formula (b1-1-9) are preferable.

In formula (b1-1-1) to formula (b1-1-9), Q ¹ , Q ² and L ^b2 are the same as described above. R ^b2 and R ^b3 each independently represent a C _1-4 aliphatic hydrocarbon group (preferably a methyl group).

  Next, specific sulfonate anions are exemplified. First, a sulfonate anion containing an unsubstituted alicyclic hydrocarbon group and a linking part (b1-1); or an alicyclic hydrocarbon group having an aliphatic hydrocarbon group as a substituent and a linking part (b1-1) Examples of sulfonic acid anions including) include the following.

Examples of the sulfonate anion containing an alicyclic hydrocarbon group having a — (CH ₂ ) _m2 —O—CO—R ^b1 group as a substituent and the linking part (b1-1) include the following.

  Examples of the sulfonate anion containing an alicyclic hydrocarbon group having a hydroxy group or a hydroxy group-containing aliphatic hydrocarbon group as a substituent and the linking part (b1-1) include the following.

  Examples of the sulfonate anion containing an alicyclic hydrocarbon group having an aromatic hydrocarbon group or an aralkyl group as a substituent and the linking part (b1-1) include the following.

  Examples of the sulfonic acid anion containing the cyclic ether and the connecting part (b1-1) include the following.

  Examples of the sulfonate anion containing the lactone ring and the connecting part (b1-1) include the following.

  Examples of the sulfonate anion containing the alicyclic hydrocarbon group having an oxo group and the connecting portion (b1-1) include the following.

  A sulfonate anion containing an unsubstituted alicyclic hydrocarbon group and a linking part (b1-2); or an alicyclic hydrocarbon group having an aliphatic hydrocarbon group as a substituent and a linking part (b1-2); Examples of the sulfonate anion containing: include the following.

Examples of the sulfonate anion containing an alicyclic hydrocarbon group having a — (CH ₂ ) _m2 —O—CO—R ^b1 group as a substituent and a linking part (b1-2) include the following.

  Examples of the sulfonate anion containing an alicyclic hydrocarbon group having a hydroxy group or a hydroxy group-containing aliphatic hydrocarbon group as a substituent and the linking part (b1-2) include the following.

  Examples of the sulfonate anion containing the lactone ring and the connecting portion (b1-2) include the following.

  Examples of the sulfonate anion containing the alicyclic hydrocarbon group having an oxo group and the connecting portion (b1-2) include the following.

  Examples of the sulfonate anion containing the alicyclic hydrocarbon group having an aromatic hydrocarbon group as a substituent and the linking part (b1-2) include the following.

  A sulfonate anion containing an unsubstituted alicyclic hydrocarbon group and a linking part (b1-3); or an alicyclic hydrocarbon group having an aliphatic hydrocarbon group as a substituent and a linking part (b1-3); Examples of the sulfonate anion containing: include the following.

  Examples of the sulfonate anion containing the alicyclic hydrocarbon group having an alkoxy group as a substituent and the linking part (b1-3) include the following.

  Examples of the sulfonate anion containing the alicyclic hydrocarbon group having a hydroxy group or a hydroxy group-containing aliphatic hydrocarbon group as a substituent and the linking part (b1-3) include the following.

  Examples of the sulfonate anion containing the alicyclic hydrocarbon group having an oxo group and the linking part (b1-3) include the following.

  Examples of the sulfonate anion containing an alicyclic hydrocarbon group having an aliphatic hydrocarbon group as a substituent and the connecting portion (b1-4) include the following.

  As a sulfonate anion containing the alicyclic hydrocarbon group which has an alkoxy group as a substituent, and a connection part (b1-4), the following are mentioned, for example.

  Examples of the sulfonate anion containing the alicyclic hydrocarbon group having a hydroxy group or a hydroxy group-containing aliphatic hydrocarbon group as a substituent and the linking part (b1-4) include the following.

  Examples of the sulfonate anion containing the alicyclic hydrocarbon group having an oxo group and the linking part (b1-4) include the following.

  Among the above-mentioned ones, the following sulfonate anions having the connecting portion (b1-1) are preferable.

  Next, the cation contained in the acid generator (B) will be described. Examples of the cation of the acid generator include onium cations such as sulfonium cations, iodonium cations, ammonium cations, benzothiazolium cations, and phosphonium cations. Among these, a sulfonium cation and an iodonium cation are preferable, and an arylsulfonium cation is more preferable.

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

In formula (b2-1), R ^{b4 to} R ^b6 each independently represent a linear or branched C _1-30 aliphatic hydrocarbon group, a C _3-30 alicyclic hydrocarbon group, or C _6-20 represents an aromatic hydrocarbon group. The aliphatic hydrocarbon group, alicyclic hydrocarbon group and aromatic hydrocarbon group may be substituted with a hydroxy group or a linear or branched C _1-12 alkoxy group; The aromatic hydrocarbon group and the alicyclic hydrocarbon group may be substituted with a C _6-20 aromatic hydrocarbon group; the aliphatic hydrocarbon group and the aromatic hydrocarbon group may be a C _3-30 alicyclic carbon group. The alicyclic hydrocarbon group and the aromatic hydrocarbon group may be substituted with a linear or branched C _1-12 aliphatic hydrocarbon group. .

In formula (b2-2), R ^b7 and R ^b8 each independently represent a hydroxy group, a linear or branched C _1-12 aliphatic hydrocarbon group, or a linear or branched chain C _1-12 alkoxy group, and n2 and o2 each independently represent 0 or 1. However, n2 or o2 being 0 means that each substituent does not exist.

In formula (b2-3), R ^b9 and R ^b10 are each independently a linear or branched C _1-12 aliphatic hydrocarbon group, C _3-36 (preferably C _4-12 ) fat. Represents a cyclic hydrocarbon group. R ^b11 represents a hydrogen atom, a linear or branched C _1-12 aliphatic hydrocarbon group, a C _4-36 alicyclic hydrocarbon group, or a C _6-20 aromatic hydrocarbon group, preferably Is a hydrogen atom. R ^b12 represents a linear or branched C _1-12 aliphatic hydrocarbon group, a C _3-12 alicyclic hydrocarbon group, or a C _6-20 aromatic hydrocarbon group. However, the aromatic hydrocarbon group of R ^b11 and R ^b12 is a linear or branched C _1-12 aliphatic hydrocarbon group, C _3-12 alicyclic hydrocarbon group, hydroxy group, or linear chain Or a branched C _1-12 alkoxy group or the like. R ^b9 and R ^b10 and R ^b11 and R ^b12 may be bonded to each other to form a 3- to 12-membered ring (preferably a 3- to 6-membered ring). The methylene group may be substituted with an oxygen atom, a sulfur atom (-S-), or a carbonyl group.

In formula (b2-4), R ^{b13 to} R ^b18 each independently represent a hydroxy group, a linear or branched C _1-12 aliphatic hydrocarbon group, a linear or branched chain C _1-12 represents an alkoxy group. L ^b8 represents a sulfur atom or an oxygen atom. p2 to u2 each independently represents an integer of 0 to 2, and v2 represents 0 or 1. However, when any one of p2 to v2 is 0, it means that each substituent does not exist. When any one of p2 to u2 is 2, any one of a plurality of R ^{b13 to} R ^b18 is present. May be the same as or different from each other.

Next, substituents included in the formulas (b2-1) to (b2-4) will be described. What was mentioned above can be illustrated as an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. Preferred aliphatic hydrocarbon groups are methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, and 2-ethylhexyl. It is a group. Preferred alicyclic hydrocarbon groups are cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclodecyl group, 2-alkyl-2-adamantyl group, 1- (1-adamantyl) -1-alkyl group. And an isobornyl group. Preferred aromatic hydrocarbon groups are phenyl group, 4-methylphenyl group, 4-ethylphenyl group, 4-t-butylphenyl group, 4-cyclohexylphenyl group, 4-methoxyphenyl group, biphenylyl group, naphthyl group. It is. Examples of the aliphatic hydrocarbon group (aralkyl group) having an aromatic hydrocarbon group as a substituent include a benzyl group. Examples of the alkoxy group include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, tert-butoxy group, n-pentyloxy group, n-hexyloxy group, heptyloxy Group, octyloxy group, 2-ethylhexyloxy group, nonyloxy group, decyloxy group, undecyloxy group, dodecyloxy group and the like. Examples of the ring formed by R ^b9 and R ^b10 include a thiolane-1-ium ring (tetrahydrothiophenium ring), a thian-1-ium ring, and a 1,4-oxathian-4-ium ring. ^Examples of the ring formed by R ^b11 and R ^b12 include an oxocycloheptane ring, an oxocyclohexane ring, an oxonorbornane ring, and an oxoadamantane ring.

  Among cation (b2-1) to cation (b2-4), cation (b2-1) is preferable, one represented by formula (b2-1-1) is more preferable, triphenylsulfonium cation, tris (p -Tolyl) sulfonium cation is more preferred.

In formula (b2-1-1), R ^{b19 to} R ^b21 each independently represent a hydroxy group, a linear or branched C _1-12 aliphatic hydrocarbon group, or a linear or branched group. A chain C _1-12 alkoxy group is represented. w2 to y2 each independently represents 0 or 1. However, any one of w2 to y2 is 0 means that each substituent is not present. w2 to y2 each independently represents an integer of 0 to 3 (preferably 0 or 1). However, when any of w2 to y2 is 0, it means that R ^{b19 to} R ^b21 do not exist, respectively, and when any of w2 to y2 is 2 or more, each of a plurality of R ^{b19 to} R ^{b21 is present.} May be the same as or different from each other.

Further, R ^{b19 to} R ^b21 in formula (b2-1-1) may each independently be a C _4-36 alicyclic hydrocarbon group. Preferred alicyclic hydrocarbon groups are an adamantyl group and an isobornyl group. The hydrogen atom of the alicyclic hydrocarbon group is a halogen atom, a hydroxy group, a linear or branched C _1-12 aliphatic hydrocarbon group, a linear or branched C _1-12. It may be substituted with an alkoxy group, a C _6-12 aryl group, a C _7-12 aralkyl group, a glycidoxy group, or a C _2-4 acyl group.

  Next, specific cations contained in the acid generator (B) are exemplified. First, specific examples of the cation (b2-1-1) include the following.

  Specific examples of the cation (b2-2) include the following.

  Specific examples of the cation (b2-3) include the following.

  Specific examples of the cation (b2-4) include the following.

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

  Preferred acid generators (B1) are those represented by formulas (B1-1) to (B1-16), and among these, acid generators (B1-1) and (B1) containing a triphenylsulfonium cation. -2), (B1-6), (B1-11), (B1-12), (B1-13) and (B1-14) are more preferred.

Acid generator (B1), for example, by the following equation, the cation M _a ⁺ sulfonate (b3-1), can be prepared by exchanging a cation Z ⁺ of the salt (b3-2) (the following formula In the formula, M _a ⁺ represents Li ⁺ , Na ⁺ , K ⁺ or Ag ⁺ , and An ⁻ represents F ⁻ , Cl ⁻ , Br ⁻ , I ⁻ , BF ₄ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , PF. ₆ ^- or ClO ₄ ^- represents a)..

  The cation exchange reaction can usually be carried out in an inert solvent such as acetonitrile, water, methanol, chloroform, methylene chloride and the like in a temperature range of about 0 to 150 ° C. (preferably about 0 to 100 ° C.). The usage-amount of a sulfonate (b3-2) is about 0.5-2 mol normally with respect to 1 mol of salts (b3-1). The obtained acid generator (B1) can be purified by washing with water, recrystallization and the like.

  The sulfonate (b3-1), which is a starting material for the cation exchange reaction, can be produced by various reaction routes. For example, the sulfonate (b3-1-1) having a linking part (b1-1) is an ester of a sulfonate (b4-1) having a carboxy group and an alcohol (b4-2) as shown in the following formula. (The symbols in the following formula are the same as above.)

Moreover, the sulfonate (b3-1-1) was obtained after the esterification reaction of the sulfonyl fluoride (b4-3) having a carboxy group and the alcohol (b4-2) as shown in the following formula. It can also be produced by hydrolyzing sulfonyl fluoride with M _b OH (in the following formula, M _b represents an alkali metal such as Li, Na, K, etc., preferably Li or Na. Is the same.)

  The amount of the sulfonate (b4-1) or sulfonyl fluoride (b4-3) used is usually about 0.2 to 3 mol, preferably 0.5 to 2 with respect to 1 mol of the alcohol (b4-2). It is about a mole.

  The esterification reaction is usually about 20 to 200 ° C. (preferably about 50 to 150 ° C.) while stirring in an aprotic solvent such as dichloroethane, toluene, ethylbenzene, monochlorobenzene, acetonitrile, N, N-dimethylformamide and the like. In the temperature range.

  In the esterification reaction, an acid catalyst may be used. Examples of the acid catalyst include organic acids such as p-toluenesulfonic acid and inorganic acids such as sulfuric acid. Although an acid catalyst may be used in excess, it is usually about 0.001 to 5 mol with respect to 1 mol of the compound having a carboxy group (carboxylic acid).

  In order to shorten the reaction time, the esterification reaction may be performed while dehydrating using a Dean Stark apparatus or the like. Further, a dehydrating agent may be added to the esterification reaction. Examples of the dehydrating agent include dicyclohexylcarbodiimide; 1-alkyl-2-halopyridinium salt; 1,1′-carbonyldiimidazole; bis (2-oxo-3-oxazolidinyl) phosphine chloride; 1-ethyl-3- (3-dimethylaminopropyl) carbodiimide hydrochloride; di-2-pyridyl carbonate; di-2-pyridylthiono carbonate; 6-methyl-2-nitrobenzoic anhydride in the presence of 4- (dimethylamino) pyridine; Etc. Although the dehydrating agent may be used in excess, the amount is usually about 0.5 to 5 mol, preferably about 1 to 3 mol, per 1 mol of carboxylic acid.

  The sulfonate having the connecting part (b1-2) can be produced by the same method as the sulfonate (b3-1-1) having the connecting part (b1-1).

The sulfonate (b3-1-3) having the connecting portion (b1-3) includes, for example, a sulfonate (b4-4) having a hydroxy group and a carboxylic acid (b4-5) or It can be produced by an esterification reaction with an acid halide (b4-6) (in the following formula, X ¹ represents a halogen. Other symbols are the same as above).

In addition, as shown in the following formula, the sulfonate (b3-1-3) is a sulfonyl fluoride (b4-7) having a hydroxy group and a carboxylic acid (b4-5) or acid halide (b4-6). After the esterification reaction, the resulting sulfonyl fluoride can also be produced by hydrolysis with M _b OH (the symbols in the following formula are the same as above).

  The amount of the sulfonate (b4-4) or sulfonyl fluoride (b4-7) used is usually 0.5 to 3 mol per 1 mol of the carboxylic acid (b4-5) or acid halide (b4-6). The degree, preferably about 1-2 mol. Other reaction conditions are the same as in the above esterification reaction. However, in the esterification reaction using acid halide (b4-6), a deoxidizing agent may be used. Examples of the deoxidizer include organic bases such as triethylamine and pyridine, or inorganic bases such as sodium hydroxide and potassium carbonate. Although the deoxidizer may be used in excess, the amount thereof is usually about 0.001 to 5 mol, preferably about 1 to 3 mol, per 1 mol of acid halide (b4-6).

  The acid halide (b4-6) can be synthesized by reacting the carboxylic acid (b4-5) with thionyl chloride, thionyl bromide, phosphorus trichloride, phosphorus pentachloride, phosphorus tribromide and the like. The acid halide synthesis reaction is usually about 20 to 200 ° C. (preferably about 50 to 150 ° C.) with stirring in an aprotic solvent such as dichloroethane, toluene, ethylbenzene, monochlorobenzene, N, N-dimethylformamide and the like. In the temperature range. In this acid halide synthesis reaction, an amine compound may be used as a catalyst.

The sulfonate (b3-1-4) having a connecting portion (b1-4) is prepared by combining a sulfonate (b4-8) having a hydroxy group with an alcohol (b4-9) It can be produced by an etherification reaction with a compound (b4-10) having a leaving group X ² (in the following formula, X ² represents a chlorine atom, a bromine atom, an iodine atom, a mesyloxy group, a tosyloxy group or a trifluoromethanesulfonyloxy group. Other symbols are the same as above.)

In addition, as shown in the following formula, the sulfonate (b3-1-4) includes a sulfonyl fluoride (b4-11) having a hydroxy group and an alcohol (b4-9) or a leaving group-containing compound (b4- After the etherification reaction with 10), the obtained sulfonyl fluoride can also be produced by hydrolysis with M _b OH (the symbols in the following formula are the same as above).

  The amount of the sulfonate (b4-8) or the sulfonyl fluoride (b4-11) used is usually 0.5 to 1 mol of the alcohol (b4-9) or the leaving group-containing compound (b4-10). About 3 mol, preferably about 1-2 mol.

  The etherification reaction is usually about 20 to 200 ° C. (preferably about 50 to 150 ° C.) while stirring in an aprotic solvent such as dichloroethane, toluene, ethylbenzene, monochlorobenzene, acetonitrile, N, N-dimethylformamide and the like. In the temperature range.

  In the etherification reaction, an acid catalyst may be used. Examples of the acid catalyst include organic acids such as p-toluenesulfonic acid and inorganic acids such as sulfuric acid. Although an acid catalyst may be used in excess, it is usually about 0.001 to 5 moles per mole of alcohol (b4-9) or leaving group-containing compound (b4-10).

  In order to shorten the reaction time, the etherification reaction may be performed while dehydrating using a Dean Stark apparatus or the like. Further, a dehydrating agent may be added to the etherification reaction. Examples of the dehydrating agent include 1,1'-carbonyldiimidazole, N, N'-dicyclohexylcarbodiimide and the like. An excessive amount of the dehydrating agent may be used, but the amount is usually about 0.5 to 5 mol, preferably 1 mol with respect to 1 mol of the alcohol (b4-9) or leaving group-containing compound (b4-10). About 1 to 3 moles.

  In the etherification reaction using the leaving group-containing compound (b4-10), a deoxidizing agent may be used. Examples of the deoxidizer include organic bases such as triethylamine and pyridine, or inorganic bases such as sodium hydroxide and potassium carbonate. Although the deoxidizer may be used in excess, the amount is usually about 0.001 to 5 mol, preferably about 1 to 3 mol, per 1 mol of the leaving group-containing compound (b4-10). is there.

  The leaving group-containing compound (b4-10) comprises alcohol (b4-9), thionyl chloride, thionyl bromide, phosphorus trichloride, phosphorus pentachloride, phosphorus tribromide, mesyl chloride, tosyl chloride, trifluoromethanesulfonic acid. It can be synthesized by reacting with an anhydride or the like. The synthesis reaction is usually about −70 to 200 ° C. (preferably about −50 to 150 ° C.) with stirring in an aprotic solvent such as dichloroethane, toluene, ethylbenzene, monochlorobenzene, N, N-dimethylformamide and the like. In the temperature range. In the synthesis reaction, a deoxidizing agent may be used. Examples of the deoxidizer include organic bases such as triethylamine and pyridine, and inorganic bases such as sodium hydroxide and potassium carbonate. An excessive amount of a deoxidizer may be used in the synthesis reaction, but the amount is usually about 0.001 to 5 mol, preferably 1 to 3 mol per 1 mol of alcohol (b4-9). It is about a mole.

<Basic compound (C)>
A basic compound (C) may be added as a quencher to the resist composition of the present invention. For example, the performance deterioration of the resist film caused by the acid deactivation accompanying the holding after exposure can be suppressed by using the basic compound (C). When the basic compound (C) is used, the amount thereof is preferably 0.01 parts by mass or more (more preferably 0.05 parts by mass or more, further preferably 0.1 parts by mass) with respect to 100 parts by mass of the resin. Above, preferably 5 parts by mass or less (more preferably 3 parts by mass or less, and still more preferably 2 parts by mass or less).

  The basic compound (C) is preferably a nitrogen-containing basic compound. Nitrogen-containing basic compounds include amines and ammonium hydroxides. The amine may be an aliphatic amine or an aromatic amine. As the aliphatic amine, any of primary amine to tertiary amine can be used. The aromatic amine may be any of an amino group bonded to an aromatic ring such as aniline and a heteroaromatic amine such as pyridine. A preferred basic compound (C) is an aromatic amine represented by the formula (C1), particularly an aniline represented by the formula (C1-1).

In the formula (C1), Ar ^c1 represents a C _6-20 aromatic hydrocarbon group. R ^c1 and R ^c2 each independently represent a hydrogen atom, a linear or branched C _1-6 aliphatic hydrocarbon group, a C _5-10 alicyclic hydrocarbon group, or a C _6-20 aromatic Represents a group hydrocarbon group. However, the aliphatic hydrocarbon group and the aromatic hydrocarbon group may be substituted with a hydroxy group, an amino group, or a linear or branched C _1-6 alkoxy group. Further, the aliphatic hydrocarbon group may be substituted with a C _6-20 aromatic hydrocarbon group, and the aromatic hydrocarbon group is a linear or branched C _1-6 aliphatic hydrocarbon group, C _It may be substituted with a _5-10 alicyclic hydrocarbon group. The alkoxy group may be substituted with a hydroxy group, an amino group, or a linear or branched C _1-6 alkoxy group, and the amino group is substituted with a C _1-4 aliphatic hydrocarbon group. It may be.

In formula (C1-1), R ^c1 and R ^c2 are the same as described above. R ^c3 represents a linear or branched C _1-6 aliphatic hydrocarbon group, a C _5-10 alicyclic hydrocarbon group, a linear or branched C _1-6 alkoxy group, Alternatively, it represents a C _6-20 aromatic hydrocarbon group. However, the aliphatic hydrocarbon group, the alkoxy group, and the aromatic hydrocarbon group may have the substituent described in the formula (C1). m3 represents an integer of 0 to 3. However, m3 being 0 means that R ^c3 does not exist. When m3 is 2 or more, a plurality of R ^{c3 s} may be the same as or different from each other.

  Examples of the aromatic amine (C1) include 1-naphthylamine and 2-naphthylamine. Examples of aniline (C1-1) include aniline, diisopropylaniline, 2-, 3- or 4-methylaniline, 4-nitroaniline, N-methylaniline, N, N-dimethylaniline, diphenylamine and the like. Of these, diisopropylaniline (particularly 2,6-diisopropylaniline) is preferable.

  Another preferred basic compound (C) is quaternary ammonium hydroxide represented by the formula (C2).

In formula (C2), R ^{c4 to} R ^c6 each independently represent a hydrogen atom, a linear or branched C _1-6 aliphatic hydrocarbon group, a C _5-10 alicyclic hydrocarbon group, Alternatively, it represents a C _6-20 aromatic hydrocarbon group. R ^c7 represents a linear or branched C _1-6 aliphatic hydrocarbon group or a C _5-10 alicyclic hydrocarbon group. However, the aliphatic hydrocarbon group and the aromatic hydrocarbon group may have the substituent described in the formula (C1).

  Examples of the quaternary ammonium hydroxide (C2) include tetramethylammonium hydroxide, tetraisopropylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide (eg, tetra-n-hexylammonium hydroxide), and tetraoctylammonium. Examples thereof include hydroxide (for example, tetra-n-octylammonium hydroxide), phenyltrimethylammonium hydroxide, 3- (trifluoromethyl) phenyltrimethylammonium hydroxide, choline, and the like. Among these, tetramethylammonium hydroxide, tetrabutylammonium hydroxide, tetrahexylammonium hydroxide, tetraoctylammonium hydroxide, phenyltrimethylammonium hydroxide, and 3-trifluoromethyl-phenyltrimethylammonium hydroxide are preferable.

  Examples of other basic compounds (C) include compounds represented by formulas (C3) to (C11).

R ^c8 in formula (C3) represents a linear or branched C _1-6 aliphatic hydrocarbon group or a C _5-10 alicyclic hydrocarbon group, and R ^c9 and R ^c10 are: A hydrogen atom, a linear or branched C _1-6 aliphatic hydrocarbon group, or a C _5-10 alicyclic hydrocarbon group is represented. R ^{c11 to} R ^c14 , R ^{c16 to} R ^c19 and R ^c22 bonded to the nitrogen atom in formulas (C4) to (C8) are each independently a hydrogen atom, linear or branched C _{1. -6 represents an} aliphatic hydrocarbon group, a C _5-10 alicyclic hydrocarbon group, or a C _6-20 aromatic hydrocarbon group. R ^c15 in formula (C6) represents a linear or branched C _1-6 aliphatic hydrocarbon group, a C _3-6 alicyclic hydrocarbon group, or a C _2-6 alkanoyl group, n3 represents an integer of 0 to 8. However, n3 being 0 means that R ^c15 does not exist. When n3 is 2 or more, a plurality of R ^{c15 s} may be the same as or different from each other. R ^c23 bonded to the aromatic carbon in formula (C8) is a hydrogen atom, a linear or branched C _1-6 aliphatic hydrocarbon group, a C _5-10 alicyclic hydrocarbon group, A chain or branched C _1-6 alkoxy group or a C _6-20 aromatic hydrocarbon group is represented. Formula (C7) and R ^{c 20,} R ^c21 and R ^c24 to R ^{c 28} to bind to aromatic carbon of formula (C9) ~ formula (C11) in each independently, C ₁ linear or branched _-6 aliphatic hydrocarbon group, C _5-10 alicyclic hydrocarbon group, linear or branched C _1-6 alkoxy group, or C _6-20 aromatic hydrocarbon group, u3 represents an integer of 0 to 3 independently. However, when any of o3 to u3 is 0, it means that each substituent does not exist. When any of o3 to u3 is 2 or more, any of a plurality of R ^{c20 to} R ^c28 is present. May be the same or different. L ^c1 and L ^{c2 in} formula (C7) and formula (C10) are each independently a C _2-6 alkylene group, a carbonyl group, —N (R ^c29 ) —, a thio group (—S—), a dithio group ( -S-S-) or a combination thereof, and R ^c29 represents a hydrogen atom or a linear or branched C _1-6 aliphatic hydrocarbon group. In addition, the aliphatic hydrocarbon group, the alkoxy group, and the aromatic hydrocarbon group in the formulas (C3) to (C11) may have the substituent described in the formula (C1).

  Examples of the compound (C3) include hexylamine, heptylamine, octylamine, nonylamine, decylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, dinonylamine, didecylamine, triethylamine, trimethylamine, tripropylamine, Tributylamine, tripentylamine, trihexylamine, triheptylamine, trioctylamine, trinonylamine, tridecylamine, methyldibutylamine, methyldipentylamine, methyldihexylamine, methyldicyclohexylamine, methyldiheptylamine, methyldioctyl Amine, methyl dinonyl amine, methyl didecyl amine, ethyl dibutyl amine, ethyl dipentyl amine, ethyl di Silamine, ethyldiheptylamine, ethyldioctylamine, ethyldinonylamine, ethyldidecylamine, dicyclohexylmethylamine, tris [2- (2-methoxyethoxy) ethyl] amine, triisopropanolamine, ethylenediamine, tetramethylenediamine, hexa Examples include methylenediamine, 4,4′-diamino-1,2-diphenylethane, 4,4′-diamino-3,3′-dimethyldiphenylmethane, 4,4′-diamino-3,3′-diethyldiphenylmethane, and the like. .

  Examples of the compound (C4) include piperazine. Examples of the compound (C5) include morpholine. Examples of the compound (C6) include piperidine and hindered amine compounds having a piperidine skeleton described in JP-A No. 11-52575. Examples of the compound (C7) include 2,2′-methylenebisaniline.

  Examples of the compound (C8) include imidazole and 4-methylimidazole. Examples of the compound (C9) include pyridine and 4-methylpyridine. Examples of the compound (C10) include 1,2-di (2-pyridyl) ethane, 1,2-di (4-pyridyl) ethane, 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′-dipicolylamine and the like Can be mentioned. Examples of the compound (C11) include bipyridine.

<Solvent (D)>
Resin (preferably resin (A) that becomes alkali-soluble by the action of an acid), acid generator (B), basic compound (C), and other optional components (E) described below are usually solvent (D ). Examples of the solvent (D) include glycol ether esters such as ethyl cellosolve acetate, methyl cellosolve acetate and propylene glycol monomethyl ether acetate; esters such as ethyl lactate, butyl acetate, amyl acetate and ethyl pyruvate; acetone, Mention may be made of ketones such as methyl isobutyl ketone, 2-heptanone and cyclohexanone; cyclic esters such as γ-butyrolactone; propylene glycol monomethyl ether.

  The content of the solvent (D) is usually 50% by mass or more (preferably 70% by mass or more, more preferably 90% by mass or more), 99% by mass or less (preferably 97% by mass) with respect to the entire resist composition. The following).

<Other optional components (E)>
The resist composition of the present invention may contain other optional component (E) as necessary. The optional component (E) is not particularly limited, and additives known in the resist field, such as sensitizers, dissolution inhibitors, other resins, surfactants, stabilizers, dyes and the like can be used.

  The resist composition of the present invention is suitable as a chemically amplified positive resist composition for immersion exposure. However, the resist composition of the present invention may be used for dry exposure. Furthermore, the resist composition of the present invention can also be used for double imaging. Hereinafter, a method for producing a resist pattern from the resist composition of the present invention will be described.

<Method for producing resist pattern>
The resist pattern manufacturing method is:
(1) A step of applying a resist composition of the present invention on a substrate to obtain a resist film (hereinafter abbreviated as “application step 1”);
(2) a step of pre-baking the resist film (hereinafter abbreviated as “pre-baking step 2”);
(3) a step of exposing the pre-baked resist film (hereinafter abbreviated as “exposure step 3”);
(4) a step of post-exposure baking of the exposed resist film (hereinafter abbreviated as “post-exposure baking step 4”);
(5) a step of developing a post exposure baked resist film with an alkali developer to obtain a resist pattern (hereinafter referred to as “development step 5”). Hereinafter, each process is demonstrated in order.

<Application process 1>
In applying the resist composition, it is desirable to previously mix the components of the resist composition in a solvent, and then filter through a filter having a pore size of about 0.2 μm or less. By filtering, the uniformity when applying the resist composition is improved.

  The substrate to which the resist composition is applied can be appropriately set depending on the application, and examples thereof include silicon wafers and quartz wafers on which sensors, circuits, transistors and the like are formed.

  A method for forming a coating film of the resist composition on the substrate is not particularly limited, and a normal coating method such as a spin coating method can be appropriately employed.

<Pre-baking process 2>
By pre-baking, the mechanical strength of the resist film can be increased and the degree of diffusion of active species (H ⁺ ) in the resist film after exposure can be adjusted. The pre-bake temperature (T _PB ) is about 50 to 200 ° C., for example.

<Exposure process 3>
The resist film after pre-baking is exposed through a mask corresponding to a target pattern (for example, a contact hole). As the exposure machine, for example, a reduction projection type exposure apparatus is used. Exposure light sources include those that emit laser light in the ultraviolet region such as KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ excimer laser (wavelength 157 nm), solid-state laser light source (YAG or semiconductor laser) Etc.) can be used, such as those that convert the wavelength of the laser light from the above and radiate the harmonic laser light in the far ultraviolet region or the vacuum ultraviolet region. What is necessary is just to select an exposure amount suitably according to the kind and content of each component.

<Post-exposure baking process 4>
In order to promote the diffusion of active species (H ⁺ ) and the reaction by the active species in the resist film after exposure, post-exposure baking is performed. The post-exposure bake temperature (T _PEB ) is usually about 50 to 200 ° C., preferably about 70 to 150 ° C.

<Development step 5>
The development may be performed by bringing a substrate provided with a resist film into contact with an ordinary developer using a developing device. As the developer, for example, an alkaline aqueous solution (specifically, an aqueous solution of tetramethylammonium hydroxide or (2-hydroxyethyl) trimethylammonium hydroxide (commonly known as choline)) is used. A surfactant may be added to the developer as necessary. It is preferable to form a resist pattern by shaking off the developer, washing with water, and then removing the water.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by the following examples, and appropriate modifications are made within a range that can meet the above and the following purposes. Of course, it is possible to implement them, and they are all included in the technical scope of the present invention.
In addition,% and part showing content thru | or the usage-amount are mass references | standards unless there is special mention.

  The weight average molecular weight (hereinafter abbreviated as “Mw”) of the resin is a value determined by gel permeation chromatography.

Apparatus: HLC-8120GPC (manufactured by Tosoh Corporation)
Column: 3 "TSKgel Multipore H _XL- M" + "guard column" (manufactured by Tosoh Corporation)
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min
Detector: RI detector Column temperature: 40 ° C
Injection volume: 100 μL
Molecular weight standard: Standard polystyrene (manufactured by Tosoh Corporation)

  The structure of the compound is NMR (GX-270 type or EX-270 type; manufactured by JEOL Ltd.), mass spectrometry (LC: Agilent 1100 type, MASS: Agilent LC / MSD type or LC / MSD TOF type) It confirmed using.

1. Synthesis and acquisition of fluorine-containing monomer Example 1
(1) Synthesis of Compound (a1-3) After charging 63.4 parts of Compound (a1-3a) and 200 parts of THF (tetrahydrofuran), stirring at room temperature and confirming dissolution of Compound (a1-3a), pyridine was added. 14.3 parts were charged and the temperature was raised to 40 ° C. Further, a mixed solution of 25.5 parts of chloroacetyl chloride and 50 parts of THF was added dropwise over 80 minutes. After dropping, the mixture was stirred at 40 ° C. for 8 hours, and the temperature was lowered to 5 ° C. 100 parts of ion-exchanged water cooled to 5 ° C. was added and stirred, and the aqueous layer was recovered by liquid separation. To the recovered aqueous layer, 100 parts of ethyl acetate was added and the layers were separated to recover the organic layer. 60 parts of 10% potassium carbonate aqueous solution at 5 ° C. was added to the recovered organic layer, washed, and separated to recover the organic layer, and then 60 parts of ion-exchanged water was further added to the recovered organic layer. The organic layer was recovered by washing with water and liquid separation. This washing operation was repeated 3 times. The recovered organic layer was concentrated to obtain 66.8 parts of compound (a1-3b).

4.48 parts of methacrylic acid, 100 parts of N, N-dimethylformamide, 3.56 parts of potassium carbonate and 0.89 parts of potassium iodide were added, and the temperature was raised to 50 ° C. After stirring at 50 ° C. for 1 hour, the temperature was raised to 100 ° C. A mixed solution of 25.93 parts of compound (a1-3b) and 77.78 parts of N, N-dimethylformamide was added to the obtained mixture over 60 minutes, and the mixture was stirred at 100 ° C. for 3 hours. After returning the obtained mixture to room temperature, 200 parts of ion-exchanged water and 400 parts of ethyl acetate were added, stirred and separated to recover the organic layer. To the recovered organic layer, 85 parts of 5% aqueous potassium carbonate solution was added, washed, and separated to recover the organic layer. To the recovered organic layer, 200 parts of ion-exchanged water was further added, washed, and separated to recover the organic layer. This washing operation was repeated 5 times. 1 part of magnesium sulfate was added to the recovered organic layer, and the mixture was stirred and then filtered to recover the organic layer. The collected organic layer is concentrated and separated by column (developing medium: silica gel 60-200 mesh manufactured by Merck & Co., developing solvent: n-heptane / ethyl acetate = 10/1), compound (a1-3) 22 .3 parts were obtained.
MASS of compound (a1-3): 548.0

Example 2
(2) Synthesis of Compound (a1-4) 4.85 parts of Compound (a1-4b) and 15.00 parts of N, N-dimethylformamide were charged and stirred at 23 ° C. for 30 minutes. To the obtained mixture, 1.04 part of potassium carbonate and 0.33 part of potassium iodide were charged and stirred at 50 ° C. for 1 hour. The obtained mixture was cooled to 40 ° C., and 2.65 parts of compound (a1-4a) (manufactured by Idemitsu Kosan Co., Ltd .: “adamantate (registered trademark) HM”) was added to N, N-dimethylformamide 15.00. The solution dissolved in the part was added dropwise over 1 hour and stirred at 75 ° C. for 5 hours. The obtained mixture was cooled to 23 ° C., 30.00 parts of chloroform and 30.00 parts of 1N (1 mol / L) hydrochloric acid were added, stirred and separated. The recovered organic layer was repeatedly washed with 30.00 parts of ion-exchanged water until the aqueous layer became neutral. To the collected organic layer, 1.2 parts of activated carbon was added, stirred and filtered. After concentrating the obtained filtrate, column separation (developing medium: silica gel 60-200 mesh manufactured by Merck & Co., developing solvent: n-heptane / ethyl acetate = 10/1), compound (a1-4) 3 .11 parts were obtained.
MASS of compound (a1-4): 684.1

Example 3
(3) Synthesis of Compound (a1-6) 3.31 parts of Compound (a1-6a) and 15.00 parts of N, N-dimethylformamide were charged and stirred at 23 ° C. for 30 minutes. To the obtained mixture, 1.04 part of potassium carbonate and 0.33 part of potassium iodide were charged and stirred at 50 ° C. for 1 hour. The obtained mixture was cooled to 40 ° C., and a solution prepared by dissolving 5.47 parts of the compound (a1-1) manufactured by Idemitsu Kosan Co., Ltd. in 15.00 parts of N, N-dimethylformamide was added dropwise over 1 hour. And stirred at 75 ° C. for 5 hours. The obtained mixture was cooled to 23 ° C., 30.00 parts of chloroform and 30.00 parts of 1N (1 mol / L) hydrochloric acid were added, stirred and separated. The recovered organic layer was repeatedly washed with 30.00 parts of ion-exchanged water until the aqueous layer became neutral. To the collected organic layer, 1.2 parts of activated carbon was added, stirred and filtered. After concentrating the obtained filtrate, by separating the column (developing medium: silica gel 60-200 mesh manufactured by Merck & Co., developing solvent: n-heptane / ethyl acetate = 10/1), compound (a1-6) 1 .84 parts were obtained.
MASS of compound (a1-6): 782.0

Example 4
(4) Synthesis of Compound (a1-7) 4.48 parts of methacrylic acid, 100 parts of N, N-dimethylformamide, 3.56 parts of potassium carbonate and 0.89 parts of potassium iodide were added, and the temperature was raised to 50 ° C. did. After further stirring for 1 hour, the temperature was raised to 100 ° C. To the resulting mixture, 17.19 parts of compound (a1-7a) and 51.56 parts of N, N-dimethylformamide were added over 60 minutes, and the mixture was stirred at 100 ° C. for 3 hours. After returning the obtained mixture to room temperature, 100 parts of ion-exchanged water and 200 parts of ethyl acetate were added, stirred and separated to recover the organic layer. To the collected organic layer, 80 parts of 5% aqueous potassium carbonate solution was added, washed and separated to recover the organic layer. To the recovered organic layer, 100 parts of ion exchange water was further added, washed, and separated to recover the organic layer. This washing operation was repeated 4 times. 1 part of magnesium sulfate was added to the recovered organic layer, and the mixture was stirred and then filtered to recover the organic layer. The collected organic layer is concentrated and separated by column (developing medium: silica gel 60-200 mesh manufactured by Merck & Co., developing solvent: n-heptane / ethyl acetate = 10/1), compound (a1-7) 4 .23 parts were obtained.
MASS of compound (a1-7): 380.0

(5) Obtaining Compound (a1-1), Compound (a1-2) and Compound (a1-5) Compound (a1-1), Compound (a1-2) and Compound (a1-5) are manufactured by Idemitsu Kosan Co., Ltd. ).
MASS of compound (a1-1): 488.0
MASS of compound (a1-2): 534.0
MASS of compound (a1-5): 530.1

Example 5
2. Synthesis of chain transfer agent (I) 15.00 parts of compound (Ia) and 45.00 parts of dioxane were charged, and 1.82 parts of sodium hydroxide was dissolved in 30.00 parts of ion-exchanged water while stirring at 23 ° C. The aqueous solution was added dropwise over 30 minutes and stirred at 100 ° C. for 5 hours. The reaction mixture was concentrated, and 50.00 parts of 1N (1 mol / L) hydrochloric acid and 200.0 parts of ethyl acetate were added to the concentrated mixture, followed by stirring and liquid separation. After concentrating the organic layer, column separation (developing medium: silica gel 60-200 mesh manufactured by Merck & Co., developing solvent: n-heptane / ethyl acetate = 3/1) was performed to obtain 9.70 parts of compound (Ib) ( Purity 100%, yield 79.6%).

  1.04 parts of thioglycolic acid, 3.42 parts of compound (Ib), 0.21 part of p-toluenesulfonic acid, and 10.40 parts of toluene were charged and stirred at 110 ° C. for 4 hours. After cooling to 23 ° C., 6.90 parts of ion exchange water and 10.40 parts of toluene were added and stirred, followed by liquid separation. 10 parts of ion-exchanged water was added to the organic layer, followed by liquid separation washing. This operation was performed three times. After concentrating the organic layer, column transfer (developing medium; silica gel 60-200 mesh manufactured by Merck & Co., developing solvent: n-heptane / ethyl acetate = 4/1) is performed to thereby obtain chain transfer agent (I) 2.88. Part (purity 100%, yield 70.0%).

Physical property data of chain transfer agent (I) MASS: 368.1
¹ H-NMR (CDCl ₃ , internal standard substance: tetramethylsilane): δ (ppm) 0.93-1.43 (m, 5H), 1.56-1.88 (m, 6H), 2.00 -2.18 (m, 3H), 3.29 (m, 2H), 4.98 (m, 1H), 5.15 (brs, 1H)

3. Synthesis of Resin (A) Resin (A1) to Resin (A14) were synthesized using the monomers (a1-1) to (a1-7) and the following monomers. Table 1 shows the types of fluorine-containing monomers used in the resins (A1) to (A14), the molar ratio of the monomers, and Mw.

Reference example 1
(1) Synthesis of Resin A1 Monomer (a2-1-1), monomer (a2-2-1), monomer (a3-1-1), monomer (a4-1-1) and monomer (a4-2-1) ) At a molar ratio of 30: 14: 6: 20: 30, and then 1.5 mass times dioxane was added to the total mass of the monomers. 1 mol of 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile) as polymerization initiators were each added to the obtained mixture with respect to the total number of moles of monomers. % And 3 mol% were added and heated at 73 ° C. for about 5 hours. Thereafter, the reaction solution is purified by pouring it into a large amount of methanol / water mixed solvent (4: 1) and precipitating three times to obtain a copolymer having an Mw of about 8100 in a yield of 45%. It was. The obtained copolymer has a structural unit derived from each monomer, and this was made into resin (A1).

Example 6
(2) Synthesis of Resin (A2) Monomer (a1-1), Monomer (a2-1-1), Monomer (a2-2-1), Monomer (a3-1-1), Monomer (a4-1-1) ) And monomer (a4-2-1) at a molar ratio of 4: 30: 10: 6: 20: 30, and the reaction temperature was 75 ° C., the same as in the synthesis of resin (A1). , A copolymer having an Mw of about 7800 was obtained in a yield of 48%. The obtained copolymer had a structural unit derived from each monomer, and this was made into resin (A2).

Example 7
(3) Synthesis of Resin (A3) Copolymer with Mw of about 7800 as in the synthesis of Resin (A2) except that monomer (a1-2) was used instead of monomer (a1-1) The coalescence was obtained in 48% yield. The obtained copolymer has a structural unit derived from each monomer, and this was made into resin (A3).

Example 8
(4) Synthesis of Resin (A4) Copolymer with Mw of about 7900, similar to the synthesis of Resin (A2), except that monomer (a1-3) was used instead of monomer (a1-1) The coalescence was obtained in 52% yield. The obtained copolymer has a structural unit derived from each monomer, and this was made into resin (A4).

Example 9
(5) Synthesis of Resin (A5) Copolymer with Mw of about 7800, similar to the synthesis of Resin (A2), except that monomer (a1-4) was used instead of monomer (a1-1) The coalescence was obtained in 48% yield. The obtained copolymer had a structural unit derived from each monomer, and this was made into resin (A5).

Example 10
(6) Synthesis of Resin (A6) Copolymer with Mw of about 8000, similar to the synthesis of Resin (A2), except that monomer (a1-5) was used instead of monomer (a1-1) The coalescence was obtained with a yield of 55%. The obtained copolymer had a structural unit derived from each monomer, and this was made into resin (A6).

Example 11
(7) Synthesis of resin (A7) 2,2′-azobisisobutyronitrile and 2,2′-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator, and chain transfer agent (I) as monomers The synthesis of the resin (A6) is performed except that 0.06 mol%, 0.18 mol%, and 4.00 mol% are added to the total number of mols, respectively, and the reaction temperature is 73 ° C. Similarly, a copolymer having an Mw of about 7900 was obtained with a yield of 74%. The obtained copolymer has a structural unit derived from each monomer, and this was made into resin (A7).

Example 12
(8) Synthesis of Resin (A8) Copolymer with Mw of about 7800 as in the synthesis of Resin (A2) except that monomer (a1-6) was used instead of monomer (a1-1) The coalescence was obtained in 48% yield. The obtained copolymer has a structural unit derived from each monomer, and this was made into resin (A8).

(9) Synthesis Example 13 of Resin (A9)
A copolymer having an Mw of about 7800 was obtained in a yield of 50% in the same manner as in the synthesis of the resin (A2) except that the monomer (a1-7) was used instead of the monomer (a1-1). . The obtained copolymer has a structural unit derived from each monomer, and this was made into resin (A9).

Comparative Example 1
(10) Synthesis of Resin (A10) Monomer (a2-1-2), monomer (a3-1-1) and monomer (a4-1-1) are charged in a molar ratio of 50:25:25, and the reaction temperature The copolymer having an Mw of about 9200 was collected in the same manner as the synthesis of the resin (A1) except that the mixture was heated to 80 ° C. and a large amount of a mixed solvent of methanol and water (3: 1) was used for purification. Obtained at a rate of 60%. This copolymer has a structural unit derived from each monomer, and this was designated as resin (A10).

Example 14
(11) Synthetic monomer (a1-1) and monomer (a6-1-1) of resin (A11) were charged at a molar ratio of 30:70, and 1.5 mass times dioxane of the total monomer amount was added to form a solution. . As initiators, azobisisobutyronitrile and azobis (2,4-dimethylvaleronitrile) were added in an amount of 0.8 mol% and 2.4 mol%, respectively, based on the total amount of monomers, and the mixture was heated at 75 ° C. for about 5 hours. Heated. Thereafter, the reaction solution was purified by pouring it into a mixed solvent of a large amount of methanol and water three times to obtain a copolymer having a Mw of 1.5 × 10 ^{4 in} a yield of 70%. This copolymer has a structural unit derived from each monomer, and this was designated as resin (A11).

Example 15
(12) Synthesis of Resin (A12) Mw is 1.4 × 10 ^{4 in the same} manner as the synthesis of Resin (A11) except that the monomer (a1-3) is used instead of the monomer (a1-1). A copolymer having a yield of 65% was obtained. The obtained copolymer has a structural unit derived from each monomer, and this was made into resin (A12).

Example 16
(13) Synthesis of Resin (A13) Mw is 1.6 × 10 ^{4 in the same} manner as the synthesis of Resin (A11) except that the monomer (a1-4) is used instead of the monomer (a1-1). A copolymer having a yield of 58% was obtained. The obtained copolymer has a structural unit derived from each monomer, and this was made into resin (A13).

Example 17
(14) Synthesis of Resin (A14) Mw is 1.3 × 10 ^{4 in the same} manner as the synthesis of Resin (A11) except that the monomer (a1-5) is used instead of the monomer (a1-1). A copolymer having a yield of 64% was obtained. The obtained copolymer has a structural unit derived from each monomer, and this was made into resin (A14).

4). Synthesis of acid generator (B1-2) To 100 parts of difluoro (fluorosulfonyl) acetic acid methyl ester and 150 parts of ion-exchanged water, 230 parts of a 30% aqueous sodium hydroxide solution was added dropwise in an ice bath. The resulting mixture was refluxed at 100 ° C. for 3 hours, cooled, and neutralized with 88 parts of concentrated hydrochloric acid. The obtained solution was concentrated to obtain 164.4 parts of sodium difluorosulfoacetate (containing inorganic salt, purity 62.7%). To 1.9 parts (purity 62.7%) of difluorosulfoacetic acid sodium salt and 9.5 parts of N, N-dimethylformamide, 1.0 part of 1,1′-carbonyldiimidazole was added for 2 hours. A mixture was prepared by stirring.

  On the other hand, 0.2 part of sodium hydride was added to 1.1 parts of 3-hydroxy-1-adamantylmethanol and 5.5 parts of N, N-dimethylformamide and stirred for 2 hours. To this solution was added the above mixture. After the resulting mixture was stirred for 15 hours, the resulting solution containing difluorosulfoacetate-3-hydroxy-1-adamantylmethyl ester sodium salt was used as it was in the next reaction. To the obtained solution containing difluorosulfoacetate-3-hydroxy-1-adamantylmethyl ester sodium salt, 17.2 parts of chloroform and 2.9 parts of 14.8% aqueous triphenylsulfonium chloride were added. After stirring for 15 hours, the organic layer was recovered by liquid separation. The remaining aqueous layer was then extracted with 6.5 parts of chloroform to recover the organic layer. Further, the above extraction operation was repeated on the remaining aqueous layer, and the organic layer was further recovered. The organic layers were combined, washed with ion-exchanged water, and then the obtained organic layer was concentrated. To the concentrate, 5.0 parts of tert-butyl methyl ether was added, stirred, and filtered to give triphenylsulfonium 1-((3-hydroxy-1-adamantyl) methoxycarbonyl) difluoromethanesulfonate (B1) as a white solid. -2) 0.2 part was obtained.

5. Characteristic evaluation Each component and solvent described in Table 2 are mixed and dissolved, and further filtered through a fluororesin filter having a pore size of 0.2 μm to prepare a liquid resist composition. Roughness and top shape were evaluated. These results are shown in Table 3.

  In Table 1, the types and amounts of the resin (A), acid generator (B), basic compound (C), and solvent are as follows.

<Resin>
A1 to A14: Resin A1 to Resin A14
<Acid generator>
B1: Salt represented by formula (B1-2)

B2: salt represented by formula (B1-3)

<Basic compound>
C1: 2,6-diisopropylaniline <solvent>
Propylene glycol monomethyl ether acetate 265.0 parts Propylene glycol monomethyl ether 20.0 parts 2-heptanone 20.0 parts γ-butyrolactone 3.5 parts

(1) Defect Evaluation Defect generation during immersion exposure was evaluated by the following simulation test. The resist composition was spin-coated on a 12-inch silicon wafer so that the film thickness after pre-baking was 0.15 μm. After applying the resist composition, it was pre-baked on a direct hot plate at the temperature (T _PB ) shown in Table 2 for 60 seconds. Using a developing machine (ACT-12; manufactured by Tokyo Electron Ltd.), the wafer on which the pre-baked resist film was formed was rinsed with water for 60 seconds. Thereafter, the number of defects in the resist film dried after rinsing was measured using a defect inspection apparatus (KLA-2360; manufactured by KLA Tencor). On the entire surface of a resist film formed on a 12-inch silicon wafer, a defect number of more than 1,000 and less than 10,000 was evaluated as a standard (Δ) having no practical problem, and the number of defects was 1,000 or less. Some were evaluated as ◯ (good) and those having a defect count of 10,000 or more were evaluated as x (defective).

(2) Evaluation of line edge roughness (LER) By applying a composition for organic antireflection film (ARC-29; manufactured by Nissan Chemical Co., Ltd.) to a silicon wafer and baking it at 205 ° C. for 60 seconds. An organic antireflection film having a thickness of 780 mm was formed. Next, the resist composition was spin-coated on the organic antireflection film so that the film thickness after drying was 85 nm. After applying the composition, the resulting silicon wafer was pre-baked on a direct hot plate at the temperature (T _PB ) described in Table 2 for 60 seconds. A silicon wafer on which a pre-baked resist film is formed uses an immersion ArF excimer stepper (XT: 1900 Gi; manufactured by ASML, NA = 1.35), and has a 1: 1 line and space pattern having a line width of 70 nm. The pattern was exposed through the mask with an exposure amount (30 to 40 mJ / cm ² ) at which the line width of the post-baked line pattern described later becomes 70 nm.

After exposure, post-exposure baking was performed on a hot plate at the temperature (T _PEB ) described in Table 2 for 60 seconds, and then paddle development was performed for 60 seconds with a 2.38% tetramethylammonium hydroxide aqueous solution.

  Observe the wall surface of the resist pattern after the lithography process with a scanning electron microscope, and the contact width of the unevenness on the side wall of the resist pattern is 3.5 nm or less, ◎, more than 3.5 nm and 4 nm or less O: A value exceeding 4 nm and 4.5 nm or less was evaluated as Δ, and a value exceeding 4.5 nm was evaluated as ×.

(3) Top shape evaluation In the same manner as the line edge roughness evaluation, the 70 nm line and space pattern was exposed with an exposure amount of 1: 1, and the obtained resist pattern was scanned with an electron microscope (S-4100; ) Manufactured by Hitachi, Ltd.). Based on Reference Example 2, the top shape is closer to a rectangle than Reference Example 2 (good), the same shape as Reference Example 2 is Δ, and the top shape is more than Reference Example 2. Those that deteriorated and were close to a T-shape, round, or those in which many pattern collapses were observed were evaluated as x (defect).

  From the above results, Example 18 to Example 32 using the resin of the present invention having structural units derived from compound (a1-1) to compound (a1-7) are compared with Reference Example 2 and Comparative Example 2. Further, it is possible to suppress the occurrence of defects during immersion exposure, and it is possible to manufacture a resist pattern with excellent line edge roughness (LER) and top shape.

  According to the compound of the present invention, a resist pattern having few defects, excellent line edge roughness and excellent top shape can be obtained from a resist composition containing a resin having a structural unit derived from the compound.

Claims (7)

Resin which has a structural unit derived from the compound represented by a formula (a1).

[In the formula (a1), R ^a1 represents a hydrogen atom, a halogen atom, or a linear or branched C _1-6 alkyl group which may have a halogen atom. R ^a2 represents a perfluoroadamantyl group, a monohydroxy-tetradecafluoroadamantyl group, a perfluorocyclohexyl group, or a monohydroxy-decafluorocyclohexyl group. L ^a1 represents a divalent C _4-36 alicyclic hydrocarbon group which may have a single bond or a fluorine atom. L ^a2 represents a single bond or a linear or branched C _1-17 alkanediyl group, and the methylene group of the alkanediyl group is an oxygen atom (—O—) or a carbonyl group (—CO—). May be substituted. ] L ^a1 is a resin according to claim 1 which is good adamantanediyl group which may have a single bond or a fluorine atom. The resin according to claim 1 or 2, further comprising a structural unit derived from at least one selected from the group consisting of a compound represented by formula (a2-1) and a compound represented by formula (a2-2). .

[In Formula (a2-1) and Formula (a2-2), L ^a3 and L ^a4 each independently represent an oxygen atom, a carbonyl group, —N (R ^a14 ) —, a linear or branched chain, A C _1-17 alkanediyl group or a combination thereof; R ^a14 represents a hydrogen atom or a linear or branched C _1-6 aliphatic hydrocarbon group; R ^a3 and R ^a4 each independently represents a hydrogen atom or a methyl group. R ^a7 represents a linear or branched C _1-6 aliphatic hydrocarbon group, and n1 represents an integer of 0-14. R ^a8 represents a linear or branched C _1-6 aliphatic hydrocarbon group or a linear or branched C _1-4 alkoxy group, and o1 is an integer of 0 to 10 Represents. However, n1 or o1 being 0 means that R ^a7 or R ^a8 does not exist, respectively, and when n1 or o1 is 2 or more, each of a plurality of R ^a7 or R ^a8 is the same or different from each other. May be. R ^a10 and R ^a11 each independently represent a linear or branched C _1-8 aliphatic hydrocarbon group or a C _3-10 alicyclic hydrocarbon group. ]   A resist composition containing the resin according to claim 1 and an acid generator.   Furthermore, the resist composition of Claim 4 containing a basic compound. Applying the resist composition according to claim 4 or 5 onto a substrate to obtain a resist film;
A step of pre-baking the resist film;
Exposing the pre-baked resist film;
A step of post-exposure baking of the exposed resist film;
And a step of developing a post-exposure baked resist film with an alkali developer to obtain a resist pattern. A compound represented by formula (a1-3), formula (a1-4), formula (a1-6) or formula (a1-7).