TWI634385B - Radiation-sensitive resin composition, method for forming photoresist pattern, acid generator, and compound - Google Patents

Abstract

An object of the present invention is to provide a radiation-sensitive resin composition having excellent LWR performance.

The solution of the present invention is a radiation-sensitive resin composition containing: a polymer having a structural unit containing an acid dissociable group; and an acid generator; the acid generator includes a sulfonate anion and a radiation-decomposable onium. A cation compound in which the sulfonate anion contains SO ₃ ^- and a carbon atom at the α position of SO ₃ ^- is bonded to a hydrogen atom or an electron donor group, and an electron withdrawing group is bonded to a carbon atom at the β position. Successor. It is preferred that the compound has a group represented by the following formula (1-1) or (1-2). In the following formulae (1-1) and (1-2), R ¹ and R ² are each independently a hydrogen atom or a monovalent electron-donating group. R ³ is a monovalent electron-withdrawing group. R ⁴ is a hydrogen atom or a monovalent hydrocarbon group.

Description

Radiation-sensitive resin composition, method for forming photoresist pattern, acid generator, and compound

The present invention relates to a radiation-sensitive resin composition, a method for forming a photoresist pattern, an acid generator, and a compound.

The radiation-sensitive resin composition used in microfabrication by lithography is irradiated with far-ultraviolet rays such as ArF excimer laser light, KrF excimer laser light, and charged particle rays such as electron rays. The exposed portion generates an acid, and by using a chemical reaction of the acid as a catalyst, a difference in the dissolution speed of the developing solution between the exposed portion and the unexposed portion is generated, and a photoresist pattern is formed on the substrate.

For this radiation-sensitive resin composition, it is required to improve the resolution required for the miniaturization of processing technology and the rectangularity of the cross-sectional shape of the photoresist pattern. In response to this request, the types or molecular structures of polymers, acid generators, and other components used in the composition have been investigated, and combinations of them have also been discussed in detail (see Japanese Patent Application Laid-Open No. 11-125907, Japanese Patent Application Laid-Open No. 8- No. 146610 and Japanese Patent Laid-Open No. 2000-298347).

Against this background, now that the photoresist pattern is gradually being refined, not only the resolution and the rectangular shape of the cross section are required, but also the line width roughness (LWR) that represents the line width change of the photoresist pattern. Excellent performance. However, the aforementioned radiation-sensitive resin composition cannot meet this requirement.

[Prior technical literature] [Patent Literature]

[Patent Document 1] Japanese Unexamined Patent Publication No. 11-125907

[Patent Document 2] Japanese Unexamined Patent Publication No. 8-146610

[Patent Document 3] Japanese Patent Laid-Open No. 2000-298347

The present invention has been made in view of the circumstances described above, and an object thereof is to provide a radiation-sensitive resin composition having excellent LWR performance.

The invention accomplished in order to solve the above-mentioned problems is a radiation-sensitive resin composition containing a polymer (hereinafter, also referred to as "[A] polymer") having a structural unit containing an acid dissociable group, and acid generation (hereinafter, also referred to as "[B] acid generator"); and the acid-generating compound with the sulfonate anion of the radiation decomposable composition comprising a cation of the sulfonate containing anionic SO ₃ ^-, and thereto SO _A hydrogen atom or an electron-donating group is bonded to a carbon atom at the α-position of _3- ^, and an electron-withdrawing group is bonded to a carbon atom at the β-position.

The method for forming a photoresist pattern of the present invention includes a step of forming a photoresist film, a step of exposing the photoresist film, and a step of developing the exposed photoresist film; and the photoresist film is radiation-sensitive. A resin composition is formed.

The acid generator of the present invention is a compound containing a sulfonate anion and a radiation-decomposable onium cation. The sulfonate anion is composed of SO ₃ ^- and a hydrogen atom is bonded to a carbon atom at the α position of the SO ₃ ^- or An electron donor group formed by bonding an electron withdrawing group to a carbon atom at the β position.

The present invention is a compound having a sulfonate anion and the radiation decomposable cations, the sulfonate containing anionic SO ₃ ^-, and thereto SO ₃ ^- bonded hydrogen atom or an electron-donating group on the α position of the carbon atom at A carbon atom at the β position is bonded with an electron withdrawing group.

According to the radiation-sensitive resin composition and the photoresist pattern of the present invention, a photoresist pattern having a small LWR can be formed. The acid generating system of the present invention can be suitably used as a component of a radiation-sensitive resin composition, and Among them, LWR performance is improved. The compound of the present invention can be suitably used as the acid generator. Therefore, these can be suitably used in a lithography step such as a semiconductor manufacturing process where further miniaturization is expected in the future.

<Radiation-sensitive resin composition>

This radiation-sensitive resin composition contains a [A] polymer and a [B] acid generator. This radiation-sensitive resin composition may also contain [C] an acid diffusion control body, [D] a fluorine atom-containing polymer (hereinafter, also referred to as "[D] polymer"), and [E] a solvent as suitable components, Other arbitrary components may be contained so long as the content of the effect range of the present invention is not impaired. Hereinafter, each component is demonstrated.

<[A] polymer>

[A] The polymer is a polymer having a structural unit (hereinafter, also referred to as a “structural unit (I)”) containing an acid dissociable group. The "acid-dissociable group" refers to a group that replaces a hydrogen atom in a carboxyl group, a phenolic hydroxyl group, and the like, and is a group that dissociates by the action of an acid. The [A] polymer in the radiation-sensitive resin composition is excellent in pattern formability due to the structural unit (I).

[A] In addition to the structural unit (I), the polymer also has a structural unit (II) having at least one member selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure, as described below. It is also possible to have other structural units other than the structural units (I) and (II). Hereinafter, each structural unit will be described.

[Construction unit (I)]

The structural unit (I) is a structural unit containing an acid dissociable group. The structural unit (I) is not particularly limited as long as it contains an acid-dissociable group, and examples thereof include a structural unit derived from an acid-dissociable ester of an unsaturated carboxylic acid, and an acid-dissociable group derived from hydroxystyrene. The structural unit of an ester, etc., but from the viewpoint of improving the pattern formability of the radiation-sensitive resin composition, the structural unit represented by the following formula (4) (hereinafter, also referred to as "structural unit (I-1)" ) Is better.

In the formula (4), R ⁷ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. R ⁸ is a monovalent hydrocarbon group having 1 to 20 carbon atoms. R ⁹ and R ¹⁰ each independently represent a monovalent chain hydrocarbon group having 1 to 10 carbon atoms or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or these groups are bonded to each other and bonded to each other The carbon atoms together form an alicyclic structure with 3 to 20 carbon atoms.

As said R <^7> , a hydrogen atom and a methyl group are preferable, and a methyl group is more preferable from a viewpoint of copolymerizability of the monomer which gives a structural unit (I).

Examples of the monovalent hydrocarbon group having 1 to 20 carbon atoms represented by the above R ⁸ include a chain hydrocarbon group having 1 to 10 carbon atoms, a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, and carbon number 6 A monovalent aromatic hydrocarbon group of ~ 20.

Examples of the chain hydrocarbon group having 1 to 10 carbon atoms represented by R ⁸ to R ¹⁰ include methyl, ethyl, n-propyl, i-propyl, n-butyl, and 2-methylpropane. Alkyl groups such as alkyl, 1-methylpropyl, t-butyl, etc .; alkenyl groups such as vinyl, propenyl, butenyl; alkynyl groups such as ethynyl, propynyl, butynyl, etc.

Examples of the alicyclic hydrocarbon group having 3 to 20 carbon atoms represented by R ⁸ to R ¹⁰ include monocyclic cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; Polycyclic cycloalkyl groups such as alkyl, adamantyl, tricyclodecyl, tetracyclododecyl, etc .; cycloalkenyl groups such as cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl, etc .; Polyalkenyl, tricyclodecenyl, tetracyclododecenyl and the like.

Examples of the monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms represented by R ⁸ include aryl groups such as phenyl, tolyl, stubyl, naphthyl, and anthracenyl; benzyl and phenethyl , Aralkyl groups such as naphthylmethyl and the like.

The R ^{8 is} preferably a chain hydrocarbon group having 1 to 10 carbon atoms and a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms.

Examples of the alicyclic structure having 3 to 20 carbon atoms, in which the chain hydrocarbon group and the alicyclic hydrocarbon group represented by R ⁹ and R ¹⁰ are bonded to each other and together with the carbon atoms bonded thereto, include, for example, cyclopropane Monocyclic cycloalkane structures such as structures, cyclobutane structures, cyclopentane structures, cyclohexane structures, cycloheptane structures, and cyclooctane structures; monocyclic rings such as cyclopentene structures, cyclohexene structures, etc. Polyenes; polycyclic cycloalkane structures such as norbornane structure, adamantane structure, tricyclodecane structure, and tetracyclododecane structure; polycyclic cycloolefins such as norbornene structure, tricyclodecane structure, etc. Construction, etc.

Among these, monocyclic and polycyclic cycloalkane structures are preferred.

Among these, R ⁸ is an alkyl group having 1 to 4 carbon atoms, and R ⁹ and R ¹⁰ are bonded to each other and the alicyclic ring constituted together with the carbon atoms bonded thereto is a polycyclic or monocyclic ring Alkanes are preferred.

Examples of the structural unit (I-1) include the structural units represented by the following formulae (4-1) to (4-4) (hereinafter, also referred to as "structural units (I-1-1) to ( I-1-4) ") and so on.

In the formulae (4-1) to (4-4), R ⁷ to R ¹⁰ are synonymous with the formula (4). i and j are each independently an integer of 1 to 4.

i and j are preferably 1.

Examples of the structural units (I-1-1) to (I-1-4) include a structural unit represented by the following formula.

In the formula, R ⁷ is synonymous with the formula (4).

As the structural unit (I), among these, the structural unit (I-1-1) and the structural unit (I-1-2) are preferred, and the structural unit having a cyclopentane structure and the adamantane structure are preferred. The structural unit is preferred, and the structural unit derived from 1-alkylcyclopentyl (meth) acrylate and the structural unit derived from 2-alkyladamantyl (meth) acrylate are preferred. The structural unit from 1-methylcyclohexyl (meth) acrylate and the structural unit derived from 2-ethyladamantyl (meth) acrylate are particularly preferred.

As the content ratio of the structural unit (I), relative to the entire structural unit constituting the [A] polymer, 5 mol% to 95 mol% is preferred, and 10 mol% to 90 mol% is preferred. 20 mol% to 80 mol% is more preferred, and 30 mol% to 70 mol% is particularly preferred. By setting the content ratio of the structural unit (I) within the above range, the pattern formability of the radiation-sensitive resin composition can be further improved.

[Structural unit (II)] The structural unit (II) is a structural unit including at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure. [A] The polymer has a structural unit (II) and can adjust the solubility in a developing solution. As a result, the radiation-sensitive resin composition can improve lithographic performance such as resolvability. In addition, the adhesion between the photoresist pattern formed by the [A] polymer and the substrate can be improved.

Examples of the structural unit (II) include a structural unit represented by the following formula.

In the above formula, R ^L1 is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

As the structural unit (II), among these, a structural unit including a lactone structure is preferable, a structural unit including a norbornane structure is more preferable, and a source derived from norbornane-yl group (formaldehyde) Base) The structural unit of acrylate is Better.

As the content ratio of the structural unit (II), in terms of the total structural unit constituting the [A] polymer, 20 mol% to 80 mol% is preferable, and 25 mol% to 70 mol% is Preferably, 30 mol% to 60 mol% is more preferred. By setting the content ratio of the structural unit (II) within the above range, the radiation-sensitive resin composition can further improve the lithographic performance such as resolvability, and the formed photoresist pattern and the adhesion of the substrate. .

[Other construction units]

[A] The polymer may have other structural units in addition to the structural units (I) and (II) described above. Examples of the other structural unit include a structural unit containing a polar group, and the like (except for the structural unit (II)). [A] The polymer has a structural unit containing a polar group, and the solubility in the developing solution can be adjusted. As a result, the lithographic performance of the radiation-sensitive resin composition can be improved. Examples of the polar group include a hydroxyl group, a carboxyl group, a cyano group, a nitro group, and a sulfonamido group. Among these, a hydroxyl group and a carboxyl group are preferable, and a hydroxyl group is more preferable.

Examples of the structural unit having this polar group include a structural unit represented by the following formula.

In the above formula, R ^A is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group.

As the content ratio of the above-mentioned structural unit having a polar group, 0 mol% to 40 mol% is preferable to 0 mol% to 30 mol relative to the entire structural unit constituting the [A] polymer. % Is more preferable, and 0 to 20 mole% is more preferable. By setting the content ratio of the structural unit having a polar group within the above range, the lithographic performance such as the resolvability of the radiation-sensitive resin composition can be further improved.

[A] The polymer may have a structural unit other than the above-mentioned structural unit having a polar group as another structural unit. The content ratio of such a structural unit is preferably 30 mol% or less, and more preferably 20 mol% or less, relative to the entire structural unit constituting the [A] polymer.

<[A] Synthesis method of polymer>

[A] The polymer system can be synthesized, for example, by using a radical polymerization initiator or the like to polymerize a monomer imparted to each structural unit in an appropriate solvent.

Examples of the radical polymerization initiator include azobisisobutyronitrile (AIBN), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile), and 2 , 2'-Azobis (2-cyclopropylpropionitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), dimethyl2,2'-azobisisobutyl Azo radical initiators such as acid esters; peroxide radical initiators such as benzamyl peroxide, t-butyl hydroperoxide and cumene peroxide. Among these are based on AIBN and dimethyl 2,2'-azobisisobutyrate, and AIBN is more preferred. These radical initiators may be used singly or in combination of two or more kinds.

Examples of the solvent used in the above polymerization include n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, etc .; cyclohexane, cycloheptane, cyclooctane, decalin, Naphthenes such as norbornane; aromatic hydrocarbons such as benzene, toluene, stubble, ethylbenzene, cumene; chlorobutane, bromohexane, dichloroethane, dibromide Methyl, chlorobenzene and other halogenated hydrocarbons; ethyl acetate, n-butyl acetate, i-butyl acetate, methyl propionate and other saturated carboxylic acid esters; acetone, methyl ethyl ketone, 4-methyl Ketones such as 2-pentanone and 2-heptanone; ethers such as tetrahydrofuran, dimethoxyethane, diethoxyethane; methanol, ethanol, 1-propanol, 2-propane Alcohols, alcohols such as 4-methyl-2-pentanol, and the like. These solvents used in the polymerization may be used singly or in combination of two or more kinds.

The reaction temperature in the above polymerization is usually 40 ° C to 150 ° C, and preferably 50 ° C to 120 ° C. The reaction time is usually 1 hour to 48 hours, and preferably 1 hour to 24 hours.

[A] The polystyrene-equivalent weight average molecular weight (Mw) of the polymer obtained by gel permeation chromatography (GPC) is not particularly limited, preferably 1,000 to 50,000, and more preferably 2,000 to 30,000. It is more preferably 3,000 to 15,000, and particularly preferably 4,000 to 12,000. [A] If the Mw of the polymer is less than the above lower limit In some cases, the heat resistance of the obtained photoresist film may decrease. [A] When the Mw of the polymer exceeds the above-mentioned upper limit, the developability of the photoresist film may decrease.

[A] The ratio (Mw / Mn) of the Mw of the polymer to the polystyrene-equivalent number average molecular weight (Mn) obtained by GPC is usually 1 or more and 5 or less, preferably 1 or more and 3 or less, and more than 1 2 or less is more preferable.

The Mw and Mn of the polymer in this specification are values measured using gel permeation chromatography (GPC) based on the following conditions.

GPC column: 2 G2000HXL, 1 G3000HXL, 1 G4000HXL (above, manufactured by Tosoh)

Column temperature: 40 ℃

Precipitation solvent: tetrahydrofuran (manufactured by Wako Pure Chemical Industries)

Flow rate: 1.0mL / min

Sample concentration: 1.0% by mass

Sample injection volume: 100 μL

Detector: Differential refractometer

Standard substance: monodisperse polystyrene

[A] The content of the polymer is preferably 70% by mass or more, more preferably 80% by mass or more, and more preferably 85% by mass or more relative to the solid content of the radiation-sensitive resin composition. .

<[B] acid generator>

[B] The acid generator is a compound containing a sulfonate anion (hereinafter, also referred to as "sulfonate anion (A)") and a radiation-decomposable onium cation (hereinafter, also referred to as "compound (I)"); the sulfonate anion containing SO ₃ ^- and this SO ₃ ^- of the α position of the carbon atom bonded to a hydrogen atom or an electron-donating group, the position on the β carbon atom bonded to a group formed by electron withdrawing. This radiation-sensitive resin composition is excellent in LWR performance by containing a [B] acid generator.

[Compound (I)]

The compound (I) is a compound having a sulfonate anion (A) and a radiation-decomposable onium cation. Hereinafter, description will be made in the order of the sulfonate anion (A) and the radiation-decomposable onium cation.

(Sulfonate anion (A))

Sulfonate anion (A) is a system comprising SO ₃ ^-, and thereto SO ₃ ^- bonded hydrogen atom or an electron-donating group at the α position of the carbon atom at the β position bonded to carbon atoms have an electron withdrawing Sulfonate anion. "SO ₃ ^- of the α position carbon atom" means SO ₃ ^- carbon atoms are bonded, the "SO ₃ ^- position of the β carbon atom" means in the position adjacent to the α carbon atom this carbon atom. The compound (I) of the [B] acid generator in the radiation-sensitive resin composition is excellent in LWR performance by having a sulfonate anion (A). The reason why the sulfonate anion (A) has the above-mentioned structure and that the radiation-sensitive resin composition is excellent in LWR performance is not sufficiently clear. For example, the sulfonate anion (A) is at the α position in the sulfonate anion (A). The electron-withdrawing group is not bonded, and only one electron-withdrawing group is bonded to the carbon atom at the β position, so that the [B] acid generator can exhibit more moderate acidity than the previous acid generator.

The electron-donating group is not particularly limited as long as it is a group which is easier to donate electrons to the bonding atom side than a hydrogen atom. The electron-donating group may be a monovalent group or a divalent or higher group. The base is better. In addition, the above-mentioned electron-donor system may be bonded to one carbon atom at the α-position, or may be bonded to two.

Examples of the electron-donating group include a hydrocarbon group, a hydroxyl group, an oxyhydrocarbon group, an oxycarbonyl hydrocarbon group, an amine group, a hydrocarbon-substituted amino group, a hydrocarbon-substituted amido group, and the like. From the viewpoint that the acidity of the acid generated from the compound (I) can be considered to be more moderate, among these, a hydrocarbon group, an oxyhydrocarbon group, and an amine group are preferred.

As the monovalent electron donating group, and examples include, -R ', - OH, -OR ', - OCOR ', - NH 2, -NR' 2, -NHR ', - NHCOR' and the like. R 'is a monovalent hydrocarbon group.

Examples of the monovalent hydrocarbon group represented by the aforementioned R ′ include alkyl groups such as methyl, ethyl, propyl, and butyl; alkenyl groups such as vinyl, propenyl, and butenyl; ethynyl, Monovalent chain hydrocarbon groups such as alkynyl such as propynyl, butynyl; cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, norbornyl, adamantyl, etc. cycloalkyl; cyclopropene Monovalent alicyclic hydrocarbon groups such as cycloalkenyl, cyclobutenyl, cyclopentenyl, norbornenyl, etc .; phenyl, tolyl, stubyl, podyl, naphthyl, methylnaphthyl , Aryl groups such as anthracenyl, methylanthryl, and the like; monovalent aromatic hydrocarbon groups such as aralkyl such as benzyl, phenethyl, phenylpropyl, naphthylmethyl, and anthrylmethyl; and the like.

Examples of the monovalent group of electron donor, the degree of acidity of the acid may be produced from the compound of (I) as the more modest view, among these lines to -R ', - OR', - NH 2, -NHR ' -NR ' _{2 is} preferred, -R' (monovalent hydrocarbon group) is preferred, monovalent chain hydrocarbon group is preferred, alkyl group is more preferred, methyl group is particularly preferred.

As the carbon atom bonded to the α-position, a hydrogen atom is preferred from the viewpoint of ease of synthesis of the compound (I).

The electron-withdrawing group is not particularly limited as long as it is a group that easily attracts electrons from the bonding atom side with the hydrogen atom. The electron-withdrawing group may be a monovalent group or a divalent group or more, but a monovalent group Better. The electron withdrawing group is bonded to one carbon atom at the β position.

Examples of the electron withdrawing group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a halogenated hydrocarbon group, a nitro group, a cyano group, a formamyl group, a carbonyl hydrocarbon group, a carbonyloxy hydrocarbon group, and a sulfonyl hydrocarbon group. , Carboxyl, sulfonic acid, etc. From the viewpoint of the ease of synthesis of the compound (I), among these, a cyano group, a halogen atom, and a halogenated hydrocarbon group are preferred, and the acidity of the acid generated from the compound (I) can be regarded as a more moderate point. A cyano group, a fluorine atom and a fluorinated hydrocarbon group are more preferred, a fluorine atom and a fluorinated hydrocarbon group are more preferred, and a fluorinated hydrocarbon is particularly preferred.

Examples of the monovalent electron-withdrawing group include a halogen atom, a monovalent halogenated hydrocarbon group, a nitro group, a cyano group, a methylamino group, -COR ', -CO ₂ R', -SO ₂ R ', a carboxyl group, Sulfonic group and so on. R 'is a monovalent hydrocarbon group.

Examples of the monovalent halogenated hydrocarbon group include the following, and examples of the monovalent fluorinated hydrocarbon group include the following: Fluoromethyl, difluoromethyl, trifluoromethyl, fluoroethyl, difluoroethyl, trifluoroethyl, pentafluoroethyl, trifluoropropyl, hexafluoropropyl, heptafluoropropyl, nonafluoro Butyl fluorinated alkyl groups; fluorinated alkenyl groups such as fluorovinyl and trifluorovinyl groups; fluorinated alkynyl groups such as fluoroethynyl; monovalent fluorinated chain hydrocarbon groups; fluorocyclopentyl; perfluoro Cyclopentyl, perfluorocyclohexyl, perfluoronorbornyl, perfluoroadamantyl, etc. fluorinated cycloalkyl; fluorocyclopentenyl, difluoronorbornyl, etc. Valent fluorinated alicyclic hydrocarbon groups, fluorophenyl, difluorophenyl, trifluorophenyl, pentafluorophenyl, fluorotolyl, trifluorotolyl, fluoronaphthyl, fluoroanthryl, etc. ; Fluorinated aralkyl groups such as fluorobenzyl, difluorobenzyl, fluoronaphthylmethyl, etc. Examples of monovalent chlorinated hydrocarbon groups include trichloromethyl, perchlorocyclohexyl, pentachlorophenyl, etc. Examples of monovalent brominated hydrocarbon groups include tribromomethyl, perbromocyclohexyl, and pentabromophenyl. Examples of monovalent iodinated hydrocarbon groups include triiodomethyl, periodocyclohexyl, pentabromo Iodophenyl and the like.

Examples of the monovalent hydrocarbon group represented by R 'include the same groups as those exemplified as the monovalent hydrocarbon group represented by R'.

As the monovalent electron-withdrawing group, among these, a cyano group, a fluorine atom, and a monovalent fluorinated hydrocarbon group are preferred, a fluorine atom and a monovalent fluorinated hydrocarbon group are more preferred, and a monovalent fluorinated hydrocarbon group is preferred. More preferably, it is characterized by perfluoroalkyl Preferably, trifluoromethyl is more preferred.

In addition to the above-mentioned one electron-withdrawing group, a carbon atom at the β-position of the SO ₃ ^- of the sulfonate anion (A) may be bonded to a group other than the electron-withdrawing group. Examples of the group other than the electron withdrawing group include a hydrogen atom and a hydrocarbon group.

(Radiodegradable onium cation)

The radiation-decomposable onium cation is a cation that is decomposed by irradiation of radiation. In the exposure section, sulfonic acid is generated from the protons generated by the decomposition of the radiation-decomposable onium cation and the sulfonate anion (A). Examples of the radiation include electromagnetic waves such as ultraviolet rays, extreme ultraviolet rays, extreme ultraviolet rays (EUV), X-rays, and gamma rays; and charged particle rays such as electron rays and alpha rays. Among these, far-ultraviolet rays, EUV and electron rays are preferred, far-ultraviolet rays are more preferred, KrF excimer laser light (248nm), ArF excimer laser light (193nm) are more preferred, and ArF excimer laser light is used as Extraordinary.

Examples of the radiation-decomposable onium cation include, for example, a radiation-decomposable onium cation containing elements such as S, I, O, N, P, Cl, Br, F, As, Se, Sn, Sb, Te, and Bi . Among these, the sulfonium cation containing element S (sulfur) and the sulfonium cation containing element I (iodine) are preferable. The cation represented by the following formula (X-1) and the following formula (X-2) The cation represented by the formula and the cation represented by the following formula (X-3) are preferred.

In the above formula (X-1), R ^a1 , R ^a2 and R ^a3 each independently represent a substituted or unsubstituted linear or branched alkyl group, substituted or unsubstituted carbon number of 1 to 12 6 to 12 aromatic hydrocarbon groups, -OSO ₂ -R ^P or -SO ₂ -R ^Q , or a ring structure in which two or more of these groups are bonded to each other. R ^P and R ^Q are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms or substituted or unsubstituted A substituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k1, k2 and k3 are each independently an integer of 0-5. When each of R ^a1 to R ^a3 and R ^P and R ^Q is plural, the plural R ^a1 to R ^a3 and R ^P and R ^Q may be the same or different.

In the formula (X-2), R ^b1 is a substituted or unsubstituted linear or branched alkyl group having 1 to 8 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 8 carbon atoms. k4 is an integer from 0 to 7. When R ^b1 is plural, the plural R ^b1 may be the same or different, and the plural R ^b1 may also represent a ring structure formed by combining with each other. R ^b2 is a substituted or unsubstituted linear or branched alkyl group having 1 to 7 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 or 7 carbon atoms. k5 is an integer from 0 to 6. When R ^b2 is plural, the plural R ^b2 may be the same or different, and the plural R ^b2 may also represent a ring structure formed by combining with each other. q is an integer from 0 to 3.

In the above formula (X-3), R ^c1 and R ^c2 each independently represent a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, and a substituted or unsubstituted carbon number 6 to 12 An aromatic hydrocarbon group, -OSO ₂ -R ^R or -SO ₂ -R ^S , or a ring structure in which two or more of these groups are bonded to each other. R ^R and R ^S are each independently a substituted or unsubstituted linear or branched alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted alicyclic hydrocarbon group having 5 to 25 carbon atoms or substituted or unsubstituted A substituted aromatic hydrocarbon group having 6 to 12 carbon atoms. k6 and k7 are each independently an integer of 0 ~ 5. When R ^c1 , R ^c2 , R ^R and R ^S are plural, each of R ^c1 , R ^c2 , R ^R and R ^S may be the same or different.

Examples of the unsubstituted linear alkyl group represented by the aforementioned R ^a1 to R ^a3 , R ^b1 , R ^b2 , R ^c1, and R ^c2 include, for example, methyl, ethyl, n-propyl, and n- Butyl and so on.

Examples of the unsubstituted branched alkyl group represented by the aforementioned R ^a1 to R ^a3 , R ^b1 , R ^b2 , R ^c1, and R ^c2 include, for example, i-propyl, i-butyl, and sec-butyl And t-butyl.

Examples of the non-substituted aromatic hydrocarbon group represented by the aforementioned R ^a1 to R ^a3 , R ^c1, and R ^c2 include aryl groups such as phenyl, tolyl, stub, mesityl, and naphthyl; Aralkyl groups such as benzyl and phenethyl.

Examples of the non-substituted aromatic hydrocarbon group represented by R ^b1 and R ^b2 include a phenyl group, a tolyl group, and a benzyl group.

Examples of the substituent that can substitute a hydrogen atom of the alkyl group and the aromatic hydrocarbon group include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, a hydroxyl group, a carboxyl group, a cyano group, and a nitro group , Alkoxy, alkoxycarbonyl, alkoxycarbonyloxy, fluorenyl, fluorenyl and the like.

Among these, a halogen atom is preferable, and a fluorine atom is more preferable.

The above R ^a1 to R ^a3 , R ^b1 , R ^b2 , R ^c1 and R ^c2 are unsubstituted linear or branched alkyl, fluorinated alkyl, unsubstituted monovalent aromatic hydrocarbon group,- OSO ₂ -R "and -SO ₂ -R" are preferred, and fluorinated alkyl groups and unsubstituted monovalent aromatic hydrocarbon groups are more preferred, and fluorinated alkyl groups are more preferred. R "is an unsubstituted monovalent alicyclic hydrocarbon group or an unsubstituted monovalent aromatic hydrocarbon group.

In the above formula (X-1), k1, k2, and k3 are preferably integers of 0 to 2, 0 or 1 is preferable, and 0 is more preferable.

K4 in the above formula (X-2) is preferably an integer of 0 to 2, 0 or 1 is more preferred, and 1 is more preferred. k5 is preferably an integer from 0 to 2, 0 or 1 is preferred, and 0 is more preferred.

K6 and k7 in the above formula (X-3) are preferably integers of 0 to 2, 0 or 1 is more preferred, and 0 is more preferred.

Examples of the sulfonium cation include cations represented by the following formulae (i-1) to (i-67).

Examples of the sulfonium cation include cations represented by the following formulae (ii-1) to (ii-39).

As the radiation-decomposable onium cation, a sulfonium cation represented by (i-1) and a sulfonium cation represented by (ii-1) are preferred, and a sulfonium cation represented by (i-1) is more preferable. good.

(Compound (I))

The compound (I) is not particularly limited as long as it is a compound having the sulfonate anion (A) and the radiation-decomposable onium cation, but has a group represented by the following formula (1-1) or (1-2) Those are better.

In the formulae (1-1) and (1-2), R ¹ and R ² are each independently a hydrogen atom or a monovalent electron-donating group. R ³ is a monovalent electron-withdrawing group. R ⁴ is a hydrogen atom or a monovalent hydrocarbon group. R ¹ to R ⁴ may also represent a ring structure in which two or more of these are bonded to each other and together with the carbon atoms bonded thereto. M ⁺ is a monovalent radiation-decomposable onium cation.

Examples of the monovalent electron-donating group represented by the aforementioned R ¹ and R ² include the same groups as those exemplified as the aforementioned monovalent electron-donating group.

The above R ¹ and R ² are preferably a hydrogen atom or a monovalent hydrocarbon group, more preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a methyl group, and particularly preferably a hydrogen atom.

Examples of the monovalent electron-withdrawing group represented by R ³ include the same groups as those exemplified as the monovalent electron-withdrawing group. Among them, a cyano group, a fluorine atom, and a monovalent fluorinated hydrocarbon group are preferable, a cyano group and a monovalent fluorinated hydrocarbon group are more preferable, a cyano group and a perfluoroalkyl group are more preferable, and a cyano group is more preferable. Trifluoromethyl is particularly preferred.

Examples of the monovalent hydrocarbon group represented by R ⁴ include a monovalent chain hydrocarbon group, a monovalent alicyclic hydrocarbon group, and a monovalent aromatic hydrocarbon group.

From the standpoint of ease of synthesis of the compound (I), the R ⁴ is preferably a hydrogen atom or a monovalent chain hydrocarbon group, more preferably a hydrogen atom or an alkyl group, and even more preferably a hydrogen atom.

Examples of the ring structure in which two of R ¹ to R ⁴ are combined with each other and together with the carbon atoms bonded thereto include, for example, a cyclobutane structure, a cyclopentane structure, and cyclohexane. Aliphatic structures such as structures, norbornane structures, and adamantane structures; aromatic ring structures such as benzene structures, toluene structures, naphthalene structures, and anthracene structures.

Among these, a ring structure composed of R ¹ and R ³ combined with each other is preferable, an aromatic ring structure is preferable, and a benzene structure is more preferable.

The compound (I) may, for example, be in the form of a low-molecular compound (hereinafter, appropriately referred to as "[B] acid generator"), or in the form of a polymer, or in the form of both.

Examples of the compound (I) of the low-molecular compound include a compound represented by the following formula (2) (hereinafter, also referred to as "compound (I-1)") and the like.

In the formula (2), Z is a group represented by the formula (1-1) or (1-2). X is a linking group of (n + 1) valence. n is an integer from 1 to 3. When n is 1, X may be a single bond. R ⁵ is a hydrogen atom or a monovalent organic group. When n is 2 or more, the plural R ⁵ may be the same or different. Z, X, and R ⁵ may also indicate a ring structure in which two or more of them are combined with each other.

Examples of the (n + 1) -valent linking group represented by X mentioned above include the following, and divalent linking groups (n = 1) include divalent hydrocarbon groups, -O-, -CO- , -COO-, -NR-, -CONH-, -S-, -SO _2- , -SO _3- , a combination of two or more of these, etc., a trivalent linking group (n = 2) Examples include a trivalent hydrocarbon group, and a combination of this hydrocarbon group with -O-, -CO-, -COO-, -NR-, -CONH-, -S-, -SO ₂ -or -SO _3- For example, a tetravalent linking group (n = 3) can be exemplified by a tetravalent hydrocarbon group, and a combination of this hydrocarbon group with -O-, -CO-, -COO-, -NR-, -CONH-, -S- , -SO ₂ -or -SO _3- .

The R is a monovalent hydrocarbon group.

The n is preferably 1 or 2, and more preferably 1.

When n is 1, X is preferably a single bond, a divalent hydrocarbon group, -O-, -COO-, -NR-, -CONH-, -S-, -SO _2- , -SO _3- Key, -COO- is preferred.

Examples of the monovalent organic group represented by the aforementioned R ⁵ include a monovalent hydrocarbon group, a heteroatom-containing group having a heteroatom group between carbon and carbon contained in the hydrocarbon group, and a substituent substituted therein. A heteroatom group is one in which a part or all of the hydrogen atoms are present.

Examples of the monovalent hydrocarbon group include a chain hydrocarbon group having 1 to 20 carbon atoms, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, and an aromatic hydrocarbon group having 6 to 20 carbon atoms.

Examples of the chain hydrocarbon group include alkyl groups such as methyl, ethyl, propyl, and butyl, alkenyl groups such as vinyl, propenyl, and butenyl, ethynyl, propynyl, and butyne Alkynyl and the like.

Examples of the alicyclic hydrocarbon group include monocyclic cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; norbornyl, adamantyl, and tricyclodecyl Ring cycloalkyl; monocyclic cycloalkenyl such as cyclopropenyl, cyclobutenyl, cyclopentenyl, cyclohexenyl; polycyclic cycloolefins such as norbornyl, tricyclodecenyl, etc. Base etc.

Examples of the aromatic hydrocarbon group include aryl groups such as phenyl, tolyl, stubyl, naphthyl, and anthracenyl; and aralkyl groups such as benzyl, phenethyl, and naphthylmethyl.

Examples of the above-mentioned group having a hetero atom include -O-, -CO-, -NH-, -S-, a combination of these, and the like.

Examples of the substituent include a hydroxyl group and a carboxyl group. Group, oxyhydrocarbyl, carbonyloxyhydrocarbyl, fluorenyl, fluorenyl, cyano, nitro, keto (= O), and the like.

The organic group may be an acid-dissociable group. By using this organic group as an acid-dissociable group, a carboxyl group is generated in the compound (I) in the exposed portion. As a result, the contrast between the exposed portion and the unexposed portion can be improved, and the radiation-sensitive resin composition can be improved. LWR performance. Examples of the acid-dissociable group include the same groups as those exemplified as the acid-dissociable group in the above-mentioned [A] polymer. Among them, a hydrocarbon group having a carbon atom of level 3 as a bond is preferable, and a cycloalkyl group having a carbon atom substituted at a bond is more preferable, and 2-alkyl-2-adamantane The base is better.

R ⁵ is preferably a monovalent organic group, more preferably a hydrocarbon group or a group containing a lactone structure, more preferably an alkyl group, a cycloalkyl group, or a group containing a lactone structure, more preferably an ethyl group, a cyclohexyl group, Adamantyl, 2-methyl-2-adamantyl, 2-oxo-3-lanthoxy-4,7,7-trimethylbicyclo [2.2.1] heptane-1-yl, norbornane Lactone-2-yl is particularly preferred.

Examples of the ring structure in which two or more of Z, X, and R ⁵ are combined with each other include, for example, the same as R ¹ to R ⁴ in the formulae (1-1) and (1-2). The rings that can be constructed are the same.

Examples of the compound (I-1) include compounds represented by the following formulae (2-1) to (2-13) (hereinafter, also referred to as "compounds (2-1) to (2-13)" )Wait.

In the formulae (2-1) to (2-13), M ⁺ is a monovalent radiation-decomposable onium cation.

Among these, compounds (2-1) to (2-7) are preferred.

Examples of the compound (I) as the polymer include polymers having a structural unit represented by the following formula (3) (hereinafter, also referred to as "structural unit (a)"). This structural unit (a) can also be introduced into the above-mentioned [A] polymer.

In the formula (3), Z is a group represented by the formula (1-1) or (1-2). Y is a divalent linking group. R ⁶ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group. Z and Y may also indicate a ring structure constituted by the combination of these.

Examples of the divalent linking group represented by Y include, for example, the linking group of X in the formula (2) as an example of the divalent linking group.

Among these, a single bond, a divalent hydrocarbon group, -O-, -COO-, and a divalent group formed by combining these are preferred.

As said R <^6> , a hydrogen atom and a methyl group are more preferable, and a methyl group is more preferable from a viewpoint of copolymerizability of the monomer which gives a structural unit (a).

Examples of the ring structure constituted by the combination of Z and Y described above include, for example, the same ring structure that can be constituted by R ¹ to R ⁴ in the formulae (1-1) and (1-2).

Examples of the structural unit (a) include the following formula (3- 1) Structural units represented by (3-8) (hereinafter also referred to as “structural units (3-1) to (3-8)”) and the like.

In the formulae (3-1) to (3-8), M ⁺ is a monovalent radiation-decomposable onium cation.

Among these, the structural units (3-1) to (3-4) are preferred.

<Synthesis method of compound (I)>

The above compound (I), for example, n lines in the above formula (2) is 1 and X is -COO- (R ⁵ bonded to a carbonyl group) of the compound (I-1) (hereinafter also referred to as "compound (2 ' ) "), Synthesis can be performed according to the following reaction scheme.

In the above reaction scheme, R ¹ and R ² are each independently a hydrogen atom or a monovalent electron-donating group. R ³ is a monovalent electron-withdrawing group. R ⁴ is a hydrogen atom or a monovalent hydrocarbon group. R ¹ to R ⁴ may also represent a ring structure in which two or more of these are bonded to each other and together with the carbon atoms bonded thereto. Z is a halogen atom. M ⁺ is a monovalent radiation-decomposable onium cation. E ^- is a monovalent anion. R ⁵ is a monovalent organic group. Q is a halogen atom, -OH or -OCOR ¹¹ . R ¹¹ is a monovalent hydrocarbon group.

Examples of the halogen atom represented by the Z and Q include a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like.

From the viewpoint of increasing the yield of the synthesis reaction, among these, chlorine atom and bromine atom are preferred, Z-based bromine atom, and Q-based chlorine atom are preferred. good.

The halogenated alcohol compound represented by the above formula (a) is reacted with sodium sulfate in a solvent such as water, and then the solvent represented by the above formula M ⁺ E ^- is contained in a solvent such as dichloromethane / water. The decomposable onium cation salt is reacted to obtain a sulfonic acid salt having a hydroxyl group represented by the formula (b). In a solvent such as dichloromethane, in the presence of a base such as triethylamine, N, N'-dimethyl-4-aminopyridine, and the like, the sulfonate is reacted with the above formula R ⁵ COQ. The compound represented by the formula is reacted to obtain the compound represented by the formula (2 ').

And, n-in the above formula (2) is 1 and X is -COO- (R ⁵ bonded to the -O-) of the compound (I-1) (hereinafter also referred to as "compound (2 ')") In this case, synthesis can be performed according to the following reaction scheme.

In the above reaction scheme, R ¹ and R ² are each independently a hydrogen atom or a monovalent electron-donating group. R ³ is a monovalent electron-withdrawing group. R ¹ to R ³ may also represent an alicyclic structure in which two or more of these are bonded to each other and together with the carbon atoms bonded thereto. M ⁺ is a monovalent radiation-decomposable onium cation. E ^- is a monovalent anion. R ⁵ is a monovalent organic group.

The compound represented by the above formula (c) is reacted with sodium bisulfite in a solvent such as methanol / acetonitrile / water to produce a sodium sulfonate represented by the above formula (d). Next, in a solvent such as dichloromethane, the sodium sulfonate salt is reacted with a salt containing a radiation-decomposable onium cation represented by the above formula M ⁺ E ^- to obtain the formula represented by the above formula (2 "). Compound.

The compound (I) other than the compound (2 ') and the compound (2 ") can also be synthesized by the same method as described above.

[Other acid generators]

[B] In addition to the compound (I), the acid generator may contain other acid generators other than the compound (I) as long as the effect of the present invention is not impaired. The form of containing other acid generators may be a form of a low-molecular compound (hereinafter, referred to as “other acid generator” as appropriate), a form of a polymer, or both forms.

The other acid generator is not particularly limited as long as it is other than the compound (I), and examples thereof include onium salt compounds and N-sulfonyloxy imide compounds.

Examples of the onium salt compound include a sulfonium salt, a tetrahydrothienium salt, a sulfonium salt, a sulfonium salt, a diazonium salt, and a pyridinium salt.

Examples of the sulfonium salt include triphenylsulfonium trifluoromethanesulfonate, triphenylsulfonium nonafluoro-n-butanesulfonate, triphenylsulfonium perfluoro-n-octanesulfonate, Triphenylphosphonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, triphenylphosphonium 2-bicyclo [2.2.1] hept-2- -1,1-difluoroethanesulfonate, triphenylsulfonium camphorsulfonate, 4-cyclohexylphenyldiphenylsulfonium trifluoromethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium Nonafluoro-n-butanesulfonate, 4-cyclohexylphenyldiphenylsulfonium perfluoro-n-octanesulfonate, 4-cyclohexylphenyldiphenylsulfonium 2-bicyclo [2.2.1] Hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-cyclohexylphenyldiphenylsulfonium camphorsulfonate, 4-methanesulfonylphenyldiphenylsulfonium Fluoromethanesulfonate, 4-Methanesulfonylphenyldiphenylfluorene nonafluoro-n-butanesulfonate, 4-Methanesulfonylphenyldiphenylfluorene perfluoro-n-octanesulfonic acid Salt, 4-methanesulfonylphenyldiphenylsulfonium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 4-methanesulfonyl Phenyldiphenylsulfonium camphorsulfonate, triphenylsulfonium 1,1,2,2-tetrafluoro-6- (1-adamantylcarbonyloxy) hexane-1-sulfonate Acid salts, triphenylphosphonium 1,1-difluoro-2- (adamantane-1-yl) ethane-1-sulfonate, and the like.

Examples of the tetrahydrothienium salt include 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothienium trifluoromethanesulfonate and 1- (4-n-butoxynaphthalene 1-yl) tetrahydrothienium nonafluoro-n-butanesulfonate, 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothienium perfluoro-n-octanesulfonate 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothienium 2-bicyclo [2.2.1] heptan-2-yl-1,1,2,2-tetrafluoroethanesulfonate , 1- (4-n-butoxynaphthalen-1-yl) tetrahydrothienium camphorsulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothienium trifluoromethanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothienium nonafluoro-n- Butanesulfonate, 1- (6-n-butoxynaphthalen-2-yl) tetrahydrothienium perfluoro-n-octanesulfonate, 1- (6-n-butoxynaphthalene-2 -Yl) tetrahydrothienium 2-bicyclo [2.2.1] heptan-2-yl-1,1,2,2-tetrafluoroethanesulfonate, 1- (6-n-butoxynaphthalene-2 -Yl) tetrahydrothienium camphorsulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothienium trifluoromethanesulfonate, 1- (3,5-dimethyl 4-hydroxyphenyl) tetrahydrothienium nonafluoro-n-butanesulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothienium perfluoro-n-octane Sulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothienium 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethyl Alkane sulfonate, 1- (3,5-dimethyl-4-hydroxyphenyl) tetrahydrothienium camphor sulfonate and the like.

Examples of the sulfonium salt include diphenylsulfonium trifluoromethanesulfonate, diphenylsulfonium nonafluoro-n-butanesulfonate, diphenylsulfonium perfluoro-n-octanesulfonate, and Phenylhydrazone 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, diphenylphosphonium camphorsulfonate, bis (4-t-butyl Phenyl) fluorene trifluoromethanesulfonate, bis (4-t-butylphenyl) fluorene nonafluoro-n-butanesulfonate, bis (4-t-butylphenyl) fluorene perfluoro-n -Octane sulfonate, bis (4-t-butylphenyl) fluorene 2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoroethanesulfonate, bis (4-t-butylphenyl) camphor sulfonate and the like.

Examples of the N-sulfonyloxyfluorenimine compound include N- (trifluoromethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dimethylfluorenimine, N -(Nonafluoro-n-butanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dimethylformimine, N- (perfluoro-n-octanesulfonyloxy) ) Bicyclo [2.2.1] hept-5-ene-2,3-dimethylformimine, N- (2-bicyclo [2.2.1] hept-2-yl-1,1,2,2-tetrafluoro ethane sulfonic yloxy) bicyclo [2.2.1] hept-5-ene-2,3-acyl imide, N- (2- (3- tetracyclo [4.4.0.1 ^2,5 .1 ^{7, 10} ] dodecyl-1,1-difluoroethanesulfonyloxy) bicyclo [2.2.1] hept-5-ene-2,3-dimethylformimine, N- (camphorsulfonyloxy) ) Bicyclo [2.2.1] hept-5-ene-2,3-dimethylformimine and the like.

As the content of the [B] acid generator, when the [B] acid generator is the [B] acid generator, it is preferably 0.1 to 30 parts by mass relative to 100 parts by mass of the [A] polymer. It is more preferably 0.5 to 20 parts by mass, and even more preferably 1 to 15 parts by mass. [B] By setting the content of the acid generator within the above range, the radiation-sensitive resin composition can improve sensitivity, and as a result, LWR performance can be improved.

As the content rate of the compound (I) in the [B] acid generator, when the [B] acid generator is the [B] acid generator, it is preferably 20% by mass to 100% by mass, and 25% by mass to 90%. Mass% is better, and 30% to 70% by mass is more preferred. By setting the content rate of the compound (I) within the above range, the radiation-sensitive resin composition can further improve LWR performance.

As the content of the compound (I) in the radiation-sensitive resin composition, when the [B] acid generator is a [B] acid generator, it is 0.1 mass based on 100 mass parts of the [A] polymer. 30 to 30 parts by mass is preferred, 1 to 15 parts by mass is preferred, and 2 to 10 parts by mass is more preferred. By setting the content of the compound (I) within the above range, the radiation-sensitive resin composition can further improve LWR performance.

<[C] acid diffusion control body>

The radiation-sensitive resin composition may contain [C] acid Scattered control body.

[C] Acid diffusion control system controls the diffusion of the acid generated from the [B] acid generator in the photoresist film due to exposure, achieves the effect of suppressing poor chemical reactions in the non-exposed area, and makes the acquired radiation feel The storage stability of the resin composition is further improved, and the resolution of the photoresist is further improved, and the change in the line width of the photoresist pattern caused by the change in the standing time from exposure to development processing can be suppressed, thereby obtaining Radiosensitive resin composition with excellent process stability. The content form of the [C] acid diffusion control body in the radiation-sensitive resin composition may be a form of a low-molecular compound (hereinafter, appropriately referred to as "[C] acid diffusion control agent"), or may be introduced. The form of a part of the polymer may be the form of both.

Examples of the [C] acid diffusion controlling agent include a compound represented by the following formula (5a) (hereinafter, also referred to as a "nitrogen-containing compound (I)") having two nitrogen atoms in the same molecule. Compounds (hereinafter, also referred to as "nitrogen-containing compound (II)"), compounds having three nitrogen atoms (hereinafter, also referred to as "nitrogen-containing compound (III)"), amido-containing compounds, urea compounds, Nitrogen heterocyclic compounds and the like.

In the formula (5a), R ¹² , R ^13, and R ¹⁴ are each independently a hydrogen atom, and may be substituted linear or branched alkyl, cycloalkyl, aryl, or aralkyl.

Examples of the nitrogen-containing compound (I) include monoalkylamines such as n-hexylamine; dialkylamines such as di-n-butylamine; and trialkylamines such as triethylamine Class; aromatic amines such as aniline.

Examples of the nitrogen-containing compound (II) include ethylenediamine, N, N, N ', N'-tetramethylethylenediamine, and the like.

Examples of the nitrogen-containing compound (III) include polyamine compounds such as polyethyleneimine and polyallylamine; polymers such as dimethylaminoethylacrylamide and the like.

Examples of the amido group-containing compound include formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N-methylacetamide, and N, N -Dimethylacetamide, propylamidine, benzamidine, pyrrolidone, N-methylpyrrolidone and the like.

Examples of the urea compound include urea, methylurea, 1,1-dimethylurea, 1,3-dimethylurea, 1,1,3,3-tetramethylurea, and 1,3- Diphenylurea, tributylthiourea and the like.

Examples of the nitrogen-containing heterocyclic compound include pyridines such as pyridine and 2-methylpyridine; morpholines such as N-propylmorpholine and N- (undecylcarbonyloxyethyl) morpholine ; Imidazoles such as 2-phenylbenzimidazole; pyrazine, pyrazole and the like.

As the nitrogen-containing organic compound, a compound having an acid-dissociable group can also be used. Examples of the nitrogen-containing organic compound having such an acid-dissociative group include Nt-butoxycarbonylpiperidine, Nt-butoxycarbonylimidazole, Nt-butoxycarbonylbenzimidazole, and Nt-butoxy Carbonyl- 2-phenylbenzimidazole, N- (t-butoxycarbonyl) di-n-octylamine, N- (t-butoxycarbonyl) diethanolamine, N- (t-butoxycarbonyl) di Cyclohexylamine, N- (t-butoxycarbonyl) diphenylamine, Nt-butoxycarbonyl-4-hydroxypiperidine, Nt-pentoxycarbonyl-4-hydroxypiperidine, and the like.

In addition, as the [C] acid diffusion controlling agent, a photo-disruptive base that is sensitive to light due to exposure and generates a weak acid may also be used. Examples of the photodegradable base include an onium salt compound that loses control of acid diffusion due to decomposition due to exposure. Examples of the onium salt compound include a sulfonium salt compound represented by the following formula (5b-1), a sulfonium salt compound represented by the following formula (5b-2), and the like.

In the formulae (5b-1) and (5b-2), R ¹⁵ to R ¹⁹ are each independently a hydrogen atom, an alkyl group, an alkoxy group, a hydroxyl group, or a halogen atom. E ^- and Q ^- are each independently based OH ^- or an anion of the following formula (5b-3) represented by the ^{-, R β -COO -, R} β -SO 3. However, R ^β is an alkyl group, an aryl group, or an aralkyl group.

[Chemical 26]

In the above formula (5b-3), R ²⁰ is a linear or branched alkyl group having 1 to 12 carbon atoms, or a straight chain having 1 to 12 carbon atoms, in which a part or all of a hydrogen atom may be substituted by a fluorine atom. Chain or branched alkoxy. u is an integer from 0 to 2.

Examples of the photo-disruptive base include a compound represented by the following formula.

As the photo-disintegrable base, among them, a sulfonium salt is preferred, a triarylsulfonium salt is more preferred, and a triphenylsulfonium salicylate and a triphenylsulfonium 10-camphorsulfonate are more preferred. .

As the content of the [C] acid diffusion control body, when the [C] acid diffusion control body is a [C] acid diffusion control agent, the content is 0 to 20 parts by mass relative to 100 parts by mass of the [A] polymer. It is preferably 0.1 parts by mass to 15 parts by mass, and more preferably 0.3 parts by mass to 10 parts by mass. When the content of the [C] acid diffusion control agent exceeds the above-mentioned upper limit, the sensitivity of the radiation-sensitive resin composition may decrease.

<[D] polymer>

[D] The polymer is a polymer containing fluorine atoms (except when it is equivalent to [A] polymer). The radiation-sensitive resin composition contains a [D] polymer. When the photoresist film is formed, its distribution may be unevenly distributed near the surface of the photoresist film due to the oil-repellent characteristics of the fluoropolymer in the film. Tends to suppress precipitation of an acid generator or an acid diffusion control agent to the liquid immersion medium during the liquid immersion exposure. In addition, by virtue of the water-repellent characteristics of the [D] polymer, the contact angle between the photoresist film and the liquid immersion medium can be controlled within a desired range, and the occurrence of bubble defects can be suppressed. In addition, the back contact angle between the photoresist film and the liquid immersion medium becomes high, and scanning exposure can be performed at high speed without leaving water droplets. Therefore, by including the [D] polymer in the radiation-sensitive resin composition, a photoresist film suitable for a liquid immersion exposure method can be formed.

The [D] polymer is not particularly limited as long as it is a polymer having a fluorine atom, and its fluorine atom content (mass%) is preferably higher than the [A] polymer in the radiation-sensitive resin composition. By having a higher fluorine atom content rate than the [A] polymer, the degree of the above-mentioned uneven distribution becomes higher, and the characteristics of the water repellency and precipitation suppression of the obtained photoresist film can be improved.

[D] The fluorine atom content rate of the polymer is preferably 1% by mass or more, more preferably 2% by mass to 60% by mass, more preferably 4% by mass to 40% by mass, and 7% by mass to 30% by mass % Is particularly good. [D] If the fluorine atom content of the polymer is less than the above lower limit, the hydrophobicity of the surface of the photoresist film may decrease. In addition, the fluorine atom content rate (mass%) of the polymer can be determined by ¹³ C-NMR spectrum measurement, and then calculated from the structure.

[D] The polymer preferably has at least one selected from the group consisting of the following structural units (Da) and structural units (Db). [D] The polymer may have one or two or more kinds of structural units (Da) and structural units (Db).

[Construction unit (Da)]

The structural unit (Da) is a structural unit represented by the following formula (6a). [D] The polymer has a structural unit (Da) and can adjust the fluorine atom content rate.

In the formula (6a), R ^D is a hydrogen atom, a methyl group, or a trifluoromethyl group. G is a single bond, an oxygen atom, a sulfur atom, -CO-O-, -SO ₂ -O-NH-, -CO-NH-, or -O-CO-NH-. R ^E is a monovalent chain hydrocarbon group having 1 to 6 carbon atoms having at least one fluorine atom or a monovalent aliphatic cyclic hydrocarbon group having 4 to 20 carbon atoms having at least one fluorine atom.

Examples of the monovalent chain hydrocarbon group having 1 to 6 carbon atoms having at least one fluorine atom represented by the above-mentioned R ^E include trifluoromethyl, 2,2,2-trifluoroethyl, and perfluoro Ethyl, 2,2,3,3,3-pentafluoropropyl, 1,1,1,3,3,3-hexafluoropropyl, perfluoro n-propyl, perfluoro i-propyl, perfluoro Fluorine n-butyl, perfluoro i-butyl, perfluoro t-butyl, 2,2,3,3,4,4,5,5-octafluoropentyl, perfluorohexyl, etc.

As represented by the above R ^E having at least one fluorine atom of carbon number 4 to 20 of the monovalent aliphatic cyclic hydrocarbon group include, for example, cyclopentyl monofluoromethyl, difluoromethyl cyclopentyl, perfluorocyclopentyl Base, monofluorocyclohexyl, difluorocyclopentyl, perfluorocyclohexylmethyl, fluoronorbornyl, fluoroadamantyl, fluorofluorenyl, fluoroisofluorenyl, fluorotricyclodecyl, fluorotetracyclo Decyl and others.

Examples of the monomer imparting the structural unit (Da) include trifluoromethyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, and 2,2,2 -Trifluoroethyloxycarbonyl methyl (meth) acrylate, perfluoroethyl (meth) acrylate, perfluoro n-propyl (meth) acrylate, perfluoro i-propyl (methyl) Acrylate, perfluoron-butyl (meth) acrylate, perfluoroi-butyl (meth) acrylate, perfluorot-butyl (meth) acrylate, 2- (1,1,1 , 3,3,3-hexafluoropropyl) (meth) acrylate, 1- (2,2,3,3,4,4,5,5-octafluoropentyl) (meth) acrylate, Perfluorocyclohexyl meth (meth) acrylate, 1- (2,2,3,3,3-pentafluoropropyl) (meth) acrylate, monofluorocyclopentyl (meth) acrylate, Difluorocyclopentyl (meth) acrylate, perfluorocyclopentyl (meth) acrylate, monofluorocyclohexyl (meth) acrylate, difluorocyclopentyl (meth) acrylate, perfluorocyclo Hexylmethyl (methyl Base) acrylate, fluorordinyl (meth) acrylate, fluoroadamantyl (meth) acrylate, fluoroamyl (meth) acrylate, fluoroisofluorenyl (meth) acrylate, fluorotrimethyl Cyclodecyl (meth) acrylate, fluorotetracyclodecyl (meth) acrylate, and the like.

Of these, 2,2,2-trifluoroethyloxycarbonylmethyl (meth) acrylate is preferred.

The content ratio of the structural unit (Da) is preferably 5 mol% to 95 mol%, and 10 mol% to 90 mol% relative to the total structural unit constituting the [D] polymer. Preferably, 25 mol% to 80 mol% is more preferred. By making such a content ratio, a higher dynamic contact angle can be found on the surface of the photoresist film during liquid immersion exposure.

[Construction unit (Db)]

The structural unit (Db) is a structural unit represented by the following formula (6b). [D] The polymer has a structural unit (Db) to improve hydrophobicity, so the dynamic contact angle of the surface of the photoresist film formed by the radiation-sensitive resin composition can be further improved.

In the formula (6b), R ^F is a hydrogen atom, a methyl group, or a trifluoromethyl group. R ²¹ is 1 to 20 carbon atoms of the hydrocarbon group (s + 1) valence, the key ²² also includes at the end side of the knot R ²¹ R & lt oxygen atom, a sulfur atom, -NR'-, carbonyl, -CO-O- Or the constructor of -CO-NH-. R 'is a hydrogen atom or a monovalent organic group. R ²² is a single bond, a divalent chain hydrocarbon group having 1 to 10 carbon atoms, or a divalent aliphatic cyclic hydrocarbon group having 4 to 20 carbon atoms. X ² is a divalent chain hydrocarbon group having 1 to 20 carbon atoms and having at least one fluorine atom. A ¹ is an oxygen atom, -NR "-, -CO-O- * or -SO ₂ -O- *. R" is a hydrogen atom or a monovalent organic group. * Indicates that the binding site is R ²¹ . R ²³ is a hydrogen atom or a monovalent organic group. s is an integer from 1 to 3. However, when s is 2 or 3, the plural R ²² , X ² , A ¹ and R ²³ may be the same or different.

When R ²³ is a hydrogen atom, it is preferable because the solubility of the [D] polymer in the alkali developing solution can be improved.

Examples of the monovalent organic group represented by R ²³ include a hydrocarbon group having 1 to 30 carbon atoms, which may have an acid dissociable group, a basic dissociable group, or a substituent.

Examples of the structural unit (Db) include a structural unit represented by the following formulae (6b-1) to (6b-3).

In the formulae (6b-1) to (6b-3), R ^{21 ′} is a divalent linear, branched, or cyclic saturated or unsaturated hydrocarbon group having 1 to 20 carbon atoms. R ^F , X ² , R ²³ and s are synonymous with those in the formula (6b). When s is 2 or 3, the plural X ² and R ²³ are respectively the same or different.

As the content ratio of the above-mentioned structural unit (6b), relative to the entire structural unit constituting the [D] polymer, 0 mol% to 90 mol% is preferable, and 5 mol% to 85 mol% is Preferably, 10 mol% to 80 mol% is more preferred. By making such a content ratio, the reduction in the dynamic contact angle of the photoresist film surface formed by the radiation-sensitive resin composition in alkali development can be improved.

[Construction unit (Dc)]

[D] In addition to the above-mentioned structural units (Da) and (Db), the polymer may also have a structural unit containing an acid-dissociable group (hereinafter, also referred to as a "structural unit (Dc)") (however, Except for units (Db)). [D] By having the structural unit (Dc), the shape of the obtained photoresist pattern becomes more favorable. Examples of the structural unit (Dc) include the structural unit (II) in the [A] polymer described above.

As the content ratio of the above-mentioned structural unit (Dc), relative to the entire structural unit constituting the [D] polymer, 5 mol% to 90 mol% is preferable, and 10 mol% to 80 mol% is Preferably, 15 mol% to 75 mol% is more preferred. If the content ratio of the structural unit (Dc) is less than the lower limit described above, the occurrence of development defects in the photoresist pattern may not be sufficiently suppressed. If the content ratio of the structural unit (Dc) exceeds the above upper limit, obtain The hydrophobicity of the surface of the photoresist film may decrease.

[Other construction units]

In addition, the [D] polymer may contain, in addition to the above-mentioned structural unit, for example, a structural unit containing an alkali-soluble group and having at least one selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure Other structural units, such as structural units, including alicyclic bases. Examples of the alkali-soluble group include a carboxyl group, a sulfonamido group, and a sulfonic acid group. Examples of the structural unit having at least one structure selected from the group consisting of a lactone structure, a cyclic carbonate structure, and a sultone structure include the structural unit (III) in the [A] polymer described above.

The content ratio of the other structural units is usually 30 mol% or less, and preferably 20 mol% or less, relative to the entire structural unit constituting the [D] polymer. When the content ratio of the other structural units exceeds the upper limit described above, the pattern-forming property of the radiation-sensitive resin composition may decrease.

The content of the [D] polymer in the radiation-sensitive resin composition is preferably 0 to 20 parts by mass, and 0.5 to 15 parts by mass relative to 100 parts by mass of the [A] polymer. It is more preferable to use 1 to 10 parts by mass. [D] When the content of the polymer exceeds the above-mentioned upper limit, the pattern-forming property of the radiation-sensitive resin composition may decrease.

<[E] Solvent>

This radiation-sensitive resin composition usually contains a [E] solvent. The [E] solvent is not particularly limited as long as it is a solvent capable of dissolving or dispersing at least the [A] polymer, the [B] acid generator, and the [C] acid diffusion control body contained as desired.

Examples of the [E] solvent include alcohol-based solvents, ether-based solvents, ketone-based solvents, amidine-based solvents, ester-based solvents, and hydrocarbon-based solvents.

Examples of the alcohol-based solvent include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol, n-pentanol, and iso -Pentanol, 2-methylbutanol, sec-pentanol, tert-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethyl Butanol, sec-heptanol, 3-heptanol, n-octanol, 2-ethylhexanol, sec-octanol, n-nonanol, 2,6-dimethyl-4-heptanol, n- Decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, furfuryl alcohol, phenol, cyclohexanol, methylcyclohexanol, 3,3 Mono-alcohol solvents such as 1,5-trimethylcyclohexanol, benzyl alcohol, diacetone alcohol; ethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 2,4-heptanediol, 2-ethyl-1,3-hexanediol, diethylene glycol, dipropylene glycol, Polyethylene glycol solvents such as triethylene glycol and tripropylene glycol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, and ethylene glycol Monohexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, diethyl Glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol monomethyl ether, propylene glycol mono Ethyl ether, Polyvalent alcohol partial ether solvents such as propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, and dipropylene glycol monopropyl ether.

Examples of the ether-based solvent include dialkyl ether-based solvents such as diethyl ether, dipropyl ether, and dibutyl ether; cyclic ether-based solvents such as tetrahydrofuran and tetrahydropyran; and diphenyl Aromatic ring-containing ether solvents such as ether, anisole (methylphenyl ether) and the like.

Examples of the ketone-based solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, diethyl ketone, methyl-iso-butyl ketone, and 2-heptane Ketone (methyl-n-pentyl ketone), ethyl-n-butyl ketone, methyl-n-hexyl ketone, di-iso-butyl ketone, trimethyl nonanone and other chain ketone solvents; Cyclic ketone solvents such as cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, methylcyclohexanone; 2,4-pentanedione, acetone, acetophenone, etc.

Examples of the amidine solvents include cyclic amidine solvents such as N, N'-dimethylimidazolinone and N-methylpyrrolidone; N-methylformamide, N, N -Dimethylformamide, N, N-diethylformamide, acetamide, N-methylacetamide, N, N-dimethylacetamide, N-methylpropylamine, etc. Chain-like amidine solvents.

Examples of the ester-based solvent include methyl acetate, ethyl acetate, n-propyl acetate, iso-propyl acetate, n-butyl acetate, iso-butyl acetate, sec-butyl acetate, and n-acetate. -E Ester, i-pentyl acetate, sec-pentyl acetate, 3-methoxybutyl acetate, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, acetic acid Acetate-based solvents such as cyclohexyl acetate, methyl cyclohexyl acetate, and n-nonyl acetate; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, and diethylene glycol Monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether ethyl Polyvalent alcohol partial ether acetates, such as esters, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether acetate, dipropylene glycol monoethyl ether acetate, and the like Solvents; lactone-based solvents such as γ-butyrolactone and valerolactone; carbonate-based solvents such as diethyl carbonate, ethyl carbonate, and propyl carbonate; glycol diacetate, methoxy acetate Triethylene glycol ester, ethyl propionate, n-butyl propionate, iso-pentyl propionate, diethyl oxalate, di-n-butyl oxalate, methyl ethyl acetate, ethyl ethyl acetate, lactic acid Methyl ester, ethyl lactate, milk n- butyl, n- amyl lactate, diethyl malonate, dimethyl phthalate, diethyl phthalate and the like.

Examples of the hydrocarbon-based solvent include n-pentane, iso-pentane, n-hexane, iso-hexane, n-heptane, iso-heptane, 2,2,4-trimethylpentane , N-octane, iso-octane, cyclohexane, methylcyclohexane and other aliphatic hydrocarbon solvents; benzene, toluene, stubble, mesitylene, ethylbenzene, trimethylbenzene, methylethyl Phenylbenzene, n-propylbenzene, iso-propylbenzene, diethylbenzene, iso-butylbenzene, Aromatic hydrocarbon solvents such as triethylbenzene, di-iso-propylbenzene, and n-pentylnaphthalene.

Among these, ester-based solvents and ketone-based solvents are preferred, polyvalent alcohol partial ether acetate-based solvents, cyclic ketone-based solvents, and lactone-based solvents are preferred. Propylene glycol monomethyl ether acetate is preferred. Esters, cyclohexanone and γ-butyrolactone are more preferred. The radiation-sensitive resin composition may contain one or two or more kinds of [E] solvents.

<Other optional ingredients>

This radiation-sensitive resin composition may contain other arbitrary components in addition to the above-mentioned [A] to [E]. Examples of the other optional components include a surfactant, an alicyclic skeleton-containing compound, a sensitizer, and the like. These other arbitrary components may be used individually by 1 type, and may use 2 or more types together.

(Surfactant)

The surfactant can achieve the effects of improving coating properties, streaks, and developability. Examples of the surfactant include polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene n-octylphenyl ether, and polyoxyethylene n-nonyl. Non-ionic surfactants such as phenyl ether, polyethylene glycol dilaurate, and polyethylene glycol distearate; commercially available products include KP341 (manufactured by Shin-Etsu Chemical Industry Co., Ltd.) and Polyflow No. 75. Same as No. 95 (above, manufactured by Kyoeisha Chemical), Eftop EF301, as EF303, as EF352 (above, manufactured by Tohkem Products), Megafac F171, and F173 (above, manufactured by DIC), Fluorad FC430, same FC431 (above, manufactured by Sumitomo 3M), Asahiguide AG710, Surflon S-382, same SC-101, same SC-102, same SC-103, same SC-104, same SC-105, same as SC-106 (above, manufactured by Asahi Glass Industry), etc. The content of the surfactant in the radiation-sensitive resin composition is usually 2 parts by mass or less based on 100 parts by mass of the [A] polymer.

(Compounds containing alicyclic skeleton)

The compound containing an alicyclic skeleton can achieve the effects of improving dry etching resistance, pattern shape, and adhesion to a substrate.

Examples of the alicyclic skeleton-containing compound include adamantane derivatives such as 1-adamantanecarboxylic acid, 2-adamantanone, and 1-adamantancarboxylic acid t-butyl ester; deoxycholic acid t-butyl Esters, deoxycholic acid t-butoxycarbonyl methyl ester, deoxycholic acid 2-ethoxyethyl deoxycholic acid esters; t-butyl lithocholic acid, t-butoxy carbonyl methyl ester And cholestyrates such as 2-ethoxyethyl lithocholic acid; 3- [2-hydroxy-2,2-bis (trifluoromethyl) ethyl] tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodecane, 2-hydroxy-9-methoxycarbonyl-5- pendant oxygen-4-oxa-tricyclo [4.2.1.0 ^3,7 ] nonane and the like. The content of the alicyclic skeleton-containing compound in the radiation-sensitive resin composition is usually 5 parts by mass or less based on 100 parts by mass of the [A] polymer.

(Sensitizer)

A sensitizer is an agent that appears to increase the amount of acid generated from the [B] acid generator and the like, and can achieve the effect of improving the "apparent sensitivity" of the radiation-sensitive resin composition.

Examples of the sensitizer include, for example, carbazoles, acetophenones, benzophenones, naphthalenes, phenols, diethylpyrene, eosin, bengal rose, perylene, anthracene, and phenothiazine Azines and so on. These sensitizers may be used alone or in combination of two or more kinds. The content of the sensitizer in the radiation-sensitive resin composition is usually 2 parts by mass or less based on 100 parts by mass of the [A] polymer.

<Method for preparing radiation-sensitive resin composition>

The radiation-sensitive resin composition can be mixed with, for example, [A] polymer, [B] acid generator, [C] acid diffusion control agent, [D] polymer, etc. in a predetermined ratio, and [ E] Solvent preparation. After mixing, the radiation-sensitive resin composition is preferably filtered using, for example, a filter having a pore size of about 0.05 μm. The solid content concentration of the radiation-sensitive resin composition is usually 0.1% to 50% by mass, preferably 0.5% to 30% by mass, and more preferably 1% to 20% by mass.

<Photoresist Pattern Forming Method>

The photoresist pattern forming method includes a step of forming a photoresist film with the radiation-sensitive resin composition (hereinafter, also referred to as a “photoresist film formation step”), and a step of exposing the above photoresist film (hereinafter, also referred to as "Exposure step Step "), and a step of developing the exposed photoresist film (hereinafter, also referred to as" developing step ").

According to this photoresist pattern formation method, since the radiation-sensitive resin composition described above is used, a photoresist pattern having a small LWR can be formed. Each step will be described below.

[Photoresist film formation step]

In this step, a photoresist film is formed from the radiation-sensitive resin composition. Examples of the substrate on which the photoresist film is formed include silicon wafers, wafers covered with silicon dioxide, and aluminum, which have been previously known. Further, for example, an organic or inorganic antireflection film disclosed in Japanese Patent Publication No. 6-12452 or Japanese Patent Application Publication No. 59-93448 may be formed on a substrate. Examples of the coating method include spin coating, cast coating, and roll coating. After coating, in order to volatilize the solvent in the coating film, pre-baking (PB) may be performed if necessary. PB temperature is usually 60 ° C ~ 140 ° C, preferably 80 ° C ~ 120 ° C. The PB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds. The thickness of the formed photoresist film is preferably 10 nm to 1,000 nm, and more preferably 10 nm to 500 nm.

In the case of performing liquid immersion exposure, the purpose of avoiding direct contact between the liquid immersion liquid and the photoresist film is to prevent the radiation-sensitive resin composition from containing the above-mentioned [D] polymer and other water-repellent polymer additives. A protective film for liquid immersion which is insoluble to a liquid immersion liquid may be provided on the formed photoresist film. Protective film for liquid immersion Solvent-peeling protective film (e.g., refer to Japanese Patent Application Laid-Open No. 2006-227632) and a developer-peeling protective film (e.g., refer to WO2005-069076, WO2006-069076) 035790). However, from the viewpoint of throughput, it is preferable to use a developing solution peeling-type protective film for liquid immersion.

[Exposure steps]

In this step, the photoresist film formed in the photoresist film forming step is irradiated with radiation through a photomask (via a liquid immersion medium such as water, as appropriate) for exposure. The radiation used for the exposure is the line width of the pattern according to the purpose, and examples include electromagnetic waves such as visible rays, ultraviolet rays, far ultraviolet rays, X-rays, and γ-rays; charged particle rays such as electron rays and α-rays. Among these, far-ultraviolet rays and electron rays are preferred. ArF excimer laser light (wavelength 193nm), KrF excimer laser light (wavelength 248nm), and electron beams are preferred. ArF excimer laser light and electron rays are preferred. Better.

When exposure is performed by liquid immersion exposure, examples of the liquid immersion liquid used include water, a fluorine-based inert liquid, and the like. The liquid immersion liquid is preferably a liquid that is transparent to the exposure wavelength and can minimize the distortion of the optical image projected on the film. The temperature coefficient of the refractive index is as small as possible, especially when the exposure light source is an ArF excimer mine. When light is emitted (wavelength 193 nm), it is preferable to use water in view of ease of acquisition and ease of operation by adding the above-mentioned viewpoints. In the case of using water, it is also possible to add additives in a small proportion to reduce the surface tension of the water and increase the interfacial activity. This additive is based on the fact that it does not dissolve the photoresist film on the wafer and can ignore the effects on the lens. The influence of the following optical coating is preferred. The water used is preferably distilled water.

After the above exposure, post-exposure baking (PEB) is performed to promote the [A] polymer caused by the acid generated from the [B] acid generator in the exposed portion of the photoresist film due to the exposure The dissociation of the acid dissociable group is preferred. With this PEB, there is a difference in solubility between the exposed portion and the unexposed portion with respect to the developing solution. The PEB temperature is usually 50 ° C to 180 ° C, based on 80 ° C to 130 ° C. PEB time is usually 5 seconds to 600 seconds, preferably 10 seconds to 300 seconds.

[Development steps]

This step is to develop the exposed photoresist film in the above exposure step. Thereby, a predetermined photoresist pattern can be formed. After development, it is generally washed with water or alcohol, and dried.

Examples of the developing solution used in the above-mentioned development include alkali hydroxide development, such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium silicate, sodium metasilicate, ammonia, ethylamine, n-propylamine, diethylamine, di-n-propylamine, triethylamine, methyldiethylamine, ethyldimethylamine, triethanolamine, tetramethylammonium hydroxide (TMAH) , Pyrrole, piperidine, choline, 1,8-diazine bicyclo- [5.4.0] -7-undecene, 1,5-diazine bicyclo- [4.3.0] -5-nonene and other bases An alkaline aqueous solution in which at least one of the sexual compounds is dissolved. Among these, a TMAH aqueous solution is preferable, and a 2.38 mass% TMAH aqueous solution is more preferable.

In the case of developing an organic solvent, examples thereof include hydrocarbon solvents and ethers. Organic solvents such as solvent, ester solvent, ketone solvent, alcohol solvent, etc., or solvents containing organic solvents. Examples of the organic solvent include one or two or more solvents listed as the [E] solvent in the radiation-sensitive resin composition. Among these, ester solvents and ketone solvents are preferred. The ester-based solvent is preferably an acetate-based solvent, and more preferably n-butyl acetate. The ketone solvent is preferably a chain ketone, and more preferably 2-heptanone. The content of the organic solvent in the developing solution is preferably 80% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, and particularly preferably 99% by mass or more. Examples of the components other than the organic solvent in the developing solution include water and silicone oil.

Examples of the developing method include a method of immersing a substrate in a tank filled with a developing solution for a predetermined period of time (immersion method), and developing the solution on the surface of the substrate by surface tension and floating for a predetermined period of time. The method of developing (puddle method), the method of spraying the developing solution on the surface of the substrate (spray method), scanning the developing solution at a certain speed on the substrate rotating at a certain speed The method of simultaneously ejecting the developing solution by the nozzle (dynamic distribution method) and the like.

<Acid generator>

The sulfonate acid generator decomposable compound anion and cation of the radiation system comprises a composition which contains a sulfonate anionic SO ₃ ^- and this SO ₃ ^- bonded hydrogen atom or an electron-donating group on the α position of the carbon atom, An electron-withdrawing group is bonded to a carbon atom at the β position.

This acid generating system can improve the radiation-sensitive resin composition containing this LWR performance. Therefore, the acid generating system can be suitably used as a component of the radiation-sensitive resin composition.

<Compound>

The compound having a sulfonic acid-based radiation decomposable anions and cations, the sulfonate containing anionic SO ₃ ^- and this SO ₃ ^- bonded hydrogen atom or an electron-donating group on the α position of the carbon atoms, the carbon in the position β An atom is bonded to an electron withdrawing group.

Since this compound has the above-mentioned properties, it can be suitably used as the acid generator.

The acid generator and the compound have been described in the item [B] Acid generator of the radiation-sensitive resin composition.

[Example]

Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited by these examples. The measurement methods of various physical properties are shown below.

[Mw and Mn]

The Mw and Mn of the polymers were measured using GPC columns (2 G2000HXL, 1 G3000HXL, 1 G4000HXL, manufactured by Tosoh) and gel permeation chromatography formed under the following conditions.

Column temperature: 40 ℃

Precipitation solvent: tetrahydrofuran (manufactured by Wako Pure Chemical Industries)

Flow rate: 1.0mL / min

Sample concentration: 1.0% by mass

Sample injection volume: 100 μL

Detector: Differential Inflection Meter

Standard substance: monodisperse polystyrene

[ ¹ H-NMR analysis and ¹³ C-NMR analysis]

^{The 1} H-NMR analysis and the ¹³ C-NMR analysis were performed using a nuclear magnetic resonance apparatus (JNM-EX270, manufactured by Nippon Denshi).

<Synthesis of compounds> [Example 1] (Synthesis of compound (B1-1))

The compound represented by the following formula (B1-1) was synthesized according to the following reaction scheme.

(Synthesis of compound (m-2))

In a 200 mL eggplant-type flask, 5.0 g (26 mmol) of 2-bromo-3,3,3-trifluoropropane-1-ol (the above-mentioned compound (m-1)), 6.5 g (52 mmol) of Na ₂ SO ₄ and H 40 mL of ₂ O was stirred at 85 ° C. for 48 hours under a nitrogen atmosphere. After cooling to room temperature, 7.5 g (25 mmol) of triphenylphosphonium chloride and 120 mL of dichloromethane were added to the reaction solution, and stirred at room temperature for 3 hours. After the reaction was completed, only the organic layer was separated and taken out. The separated organic layer was washed three times with 20 mL of water, and dried over anhydrous magnesium sulfate. Thereafter, the residue obtained by concentrating under reduced pressure was purified by silica gel column chromatography (developing solvent: dichloromethane / MeOH = 10/1 (volume ratio)) to obtain 6.2 g of a compound (m-2) ( Yield: 52%).

(Synthesis of Compound (B1-1))

In a 300 mL reaction flask, 5.0 g (11 mmol) of the compound (m-2) obtained above, 1.2 g (12 mmol) of triethylamine, and 0.13 g (1.1 mmol) of N, N-dimethyl-4-aminopyridine were added. And 100 mL of dichloromethane, the dichloromethane solution was cooled to 0 ° C., and a solution of 3.3 g (17 mmol) of 1-adamantanecarbonylsulfonium chloride in 30 mL of dichloromethane was slowly added dropwise thereto. Then, it stirred at 40 degreeC for 20 hours. After completion of the reaction, the reaction solution was washed with water and saturated saline, and the organic layer was dried over anhydrous magnesium sulfate. Thereafter, the residue obtained by concentrating under reduced pressure was purified by silica gel column chromatography (developing solvent: dichloromethane / MeOH = 12/1 (volume ratio)) to obtain 3.3 g of compound (B1-1) ( Yield: 49%).

The ¹ H-NMR data of the obtained compound (B1-1) are shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.63-1.93 (m, 15H), 3.20 (m, 2H, CH ₂ ), 6.00 (m, 1H, CH), 7.67-7.83 (m, 15H)

[Example 2] (Synthesis of compound (B1-2))

In Example 1, except that the compound represented by the following formula (m-3) was used instead of 1-adamantylcarbonylphosphonium chloride, it was performed in the same manner as in Example 1 to obtain the following formula (B1-2 ) (2.7 g, yield 45%).

The ¹ H-NMR data of the obtained compound (B1-2) are shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.00 (s, 6H, CH ₃ ), 1.25 (s, 3H, CH ₃ ), 1.70 (m, 1H, CH), 1.93 (m, 2H, CH), 2.16 ( m, 1H, CH), 3.20 (m, 2H, CH ₂ ), 6.00 (m, 1H, CH), 7.67-7.83 (m, 15H)

[Example 3] (Synthesis of compound (B1-3))

The compound represented by the following formula (B1-3) was synthesized according to the following reaction scheme.

In a 500 mL eggplant-shaped flask, 4.5 g (15.6 mmol) of the above compound (m-4), 2.1 g (20.3 mmol) of NaHSO ₃ , 75 mL of MeOH, 25 mL of CH ₃ CN, and 75 mL of H ₂ O 75 were added, and the mixture was stirred at 60 ° C. for 10 hours under a nitrogen environment. hour. After completion of the reaction, the solution was concentrated under reduced pressure until the amount of the reaction solution became about 1/4. Thereafter, 3.7 g (12.5 mmol) of triphenylphosphonium chloride and 100 mL of dichloromethane were added, and the mixture was stirred at room temperature for 5 hours. After the reaction was completed, only the organic layer was separated and taken out. The separated and taken out organic layer was washed three times with 30 mL of water, and dried with anhydrous magnesium sulfate. Thereafter, the residue obtained by concentrating under reduced pressure was purified by silica gel column chromatography (developing solvent: dichloromethane / MeOH = 12/1 (volume ratio)) to obtain 3.8 g of a compound (B1-3) ( Yield: 38%).

The ¹ H-NMR data of the obtained compound (B1-3) are shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.35 (s, 3H, CH ₃ ), 1.63-1.93 (m, 14H), 3.12 (m, 2H, CH ₂ ), 3.90 (m, 1H, CH), 7.67- 7.83 (m, 15H)

[Example 4] (Synthesis of compound (B1-4))

In Example 3, except that the compound (m-4) was replaced with a compound represented by the following formula (m-5), the same procedure as in Example 3 was performed to obtain the compound of the following formula (B1-4). 2.1 g of the indicated compound (yield: 34%).

[Chem 34]

The ¹ H-NMR data of the obtained compound (B1-4) are shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.65-1.81 (m, 2H), 2.06 (m, 2H), 2.59 (m, 2H), 3.20 (m, 3H), 3.90 (m, 1H, CH), 4.60 (m, 2H), 7.67-7.83 (m, 15H)

[Example 5] (Synthesis of compound (B1-5))

In Example 3, except that the compound (m-4) was replaced with a compound represented by the following formula (m-6), the same procedure as in Example 3 was performed to obtain the compound of the following formula (B1-5). 0.8 g of the indicated compound (yield: 19%).

The ¹ H-NMR data of the obtained compound (B1-5) are shown below.

¹ H-NMR (CDCl ₃ ) δ: 1.28 (s, 3H, CH ₃ ), 3.20 (m, 2H, CH ₂ ), 3.62 (m, 1H, CH), 4.21 (m, 2H, CH ₂ ), 7.67 -7.83 (m, 15H)

[Example 6] (Synthesis of compound (B1-6))

In Example 1, instead of 2-bromo-3,3,3-trifluoropropane-1-ol, 3-bromo-4,4,4-trifluorobutane-2-ol (the following formula (m-7)), and instead of 1-adamantanecarbonylsulfonium chloride and 1-cyclohexylcarbonylsulfonium chloride (a compound represented by the following formula (m-8)) 1 Performed in the same manner to obtain 1.2 g (yield 24%) of a compound represented by the following formula (B1-6).

The ¹ H-NMR data of the obtained compound (B1-6) are as follows.

¹ H-NMR (CDCl ₃ ) δ: 1.25 (m, 3H), 1.40-1.98 (m, 10H, CH ₂ ), 2.27 (m, 1H, CH), 3.09 (m, 1H, CH), 5.97 (m , 1H, CH), 7.67-7.83 (m, 15H)

[Example 7] (Synthesis of compound (B1-7))

5.0 g (20.4 mmol) of o- (trifluoromethyl) benzenesulfonyl chloride and 30 mL of dioxane were added to a 300 mL reaction flask, and cooled to 0 ° C. under a nitrogen environment. To this, an aqueous solution in which 1.0 g (24.5 mmol) of NaOH was dissolved in 60 mL of H ₂ O was slowly added dropwise. Then, it stirred at 0 degreeC for 1 hour. After completion of the reaction, an HCl aqueous solution of a predetermined concentration was slowly added dropwise so that the pH of the reaction solution became 7. Next, it concentrated under reduced pressure until the liquid amount of the reaction solution became about 2/3. To this was added 8.5 g (28.6 mmol) of triphenylphosphonium chloride and 150 mL of dichloromethane, and the mixture was stirred at room temperature for 5 hours. After the reaction was completed, only the organic layer was separated and taken out. The separated and taken out organic layer was washed three times with 40 mL of water, and dried with anhydrous magnesium sulfate. Thereafter, the residue obtained by concentrating under reduced pressure was purified by silica gel column chromatography (developing solvent: dichloromethane / MeOH = 12/1 (volume ratio)) to obtain 3.2 g of a compound (B1-7). (32% yield).

The ¹ H-NMR data of the obtained compound (B1-7) are as follows.

¹ H-NMR (CDCl ₃ ) δ: 7.32-7.40 (m, 3H), 7.62-7.83 (m, 16H)

<[A] Synthesis of polymer> [Synthesis Example 1] (Synthesis of Polymer (A-1))

14.2 g (35 mole%) of the following compound (m-9), 9.0 g (15 mole%) of compound (m-10), and 26.8 g (50 mole%) of compound (m-11) were dissolved in 100 g After 2-butanone, 1.98 g of 2,2'-azobisisobutyronitrile was dissolved to prepare a monomer solution. 50 g of 2-butanone was put into a 500 mL three-necked flask, and flushed with nitrogen for 30 minutes. After purging with nitrogen, the 2-butanone in the three-necked flask was stirred and simultaneously heated to 80 ° C. Next, using the dropping funnel, the prepared monomer solution was added dropwise over 3 hours. After completion of the dropping, the mixture was stirred at 80 ° C for 3 hours. After the polymerization was completed, the reaction liquid was cooled with water to cool it to 30 ° C or lower. Then, this polymerization reaction solution was put into 1,000 g of methanol to precipitate a white powder, and this was separated by filtration. The white powder that had been separated by filtration was washed twice with 200 g of each methanol, and then separated by filtration. Next, the obtained white powder polymer was dried at 50 ° C. for 17 hours to obtain a polymer (A-1) (yield: 38 g, yield: 76%). Mw of this polymer (A-1) was 7,300, and Mw / Mn was 1.42. As a result of ¹³ C-NMR analysis, the content ratio of the structural unit derived from the compound (m-9): the structural unit derived from the compound (m-10): the structural unit derived from the compound (m-11) was 36. : 11:53 (mol%).

<[D] Synthesis of Polymers> [Synthesis Example 2] (Synthesis of Polymer (D-1))

21.5 g (70 mole%) of the following compound (m-12) and 8.5 g (30 mole%) of the compound (m-13) were dissolved in 30 g of 2-butanone, and then 2,2'-coupling was added. 1.38 g of nitrogen diisobutyronitrile was prepared as a monomer solution. On the other hand, 30 g of 2-butanone was put into a 200 mL three-necked flask, and flushed with nitrogen for 30 minutes. After purging with nitrogen, the 2-butanone in the three-necked flask was stirred and simultaneously heated to 80 ° C. Next, using the dropping funnel, the prepared monomer solution was dropped into the above solution over 3 hours. After completion of the dropping, the mixture was stirred at 80 ° C for 3 hours. After the polymerization was completed, the reaction liquid was cooled with water to cool it to 30 ° C or lower. Then, this polymerization reaction solution was distilled under reduced pressure, and it was concentrated until the mass became 45 g. Thereafter, the concentrated polymerization reaction solution was put into 225 g of a methanol / water (1/1 volume ratio) mixed solution, and a white powder was precipitated and separated by decantation. The separated white powder was washed twice with 45 g of each methanol, and then separated by filtration. The obtained white powder polymer was dried at 50 ° C. for 17 hours to obtain a polymer (D-1) (yield: 13.5 g, yield: 45%). Mw of the polymer (D-1) was 7,700, and Mw / Mn was 1.44. As a result of ¹³ C-NMR analysis, the content ratio of the structural unit derived from the compound (m-12): the structural unit derived from the compound (m-13) was 69:31 (mole%).

<Preparation of radiation-sensitive resin composition>

The components used in the preparation of the radiation-sensitive resin composition are shown below.

[[B] Acid generator] (Compound (I))

Compounds (B1-1) to (B1-7) synthesized in Examples 1 to 7 above

(Other acid generators)

Compounds represented by the following formulae (B2-1) to (B2-5)

[[C] Acid diffusion control agent]

C-1: 2-phenylbenzimidazole (a compound represented by the following formula (C-1))

C-2: N-t-pentyloxycarbonyl-4-hydroxypiperidine (a compound represented by the following formula (C-2))

C-3: Triphenylsalicylate (compound represented by the following formula (C-3))

C-4: triphenylphosphonium 10-camphorsulfonate (compound represented by the following formula (C-4))

[[E] Solvent]

E-1: Propylene glycol monomethyl ether acetate

E-2: Cyclohexanone

E-3: γ-butyrolactone

[Example 8]

100 parts by mass of polymer (A-1) as the [A] polymer, 5 parts by mass of (B1-1) and (B2-4) 6 parts by mass as the [B] acid generator, and [C] acid 1.2 parts by mass of (C-1) as a diffusion control agent, 3 parts by mass of polymer (D-1) as a [D] polymer, and 2,400 parts by mass of (E-1) as a [E] solvent, (E- 2) 1,000 parts by mass and 30 parts by mass of (E-3) were mixed, and then filtered using a filter having a pore size of 0.05 μm to obtain a radiation-sensitive resin composition (J-1).

[Examples 9 to 20 and Comparative Examples 1 to 6]

Except that the components of the types and contents shown in Table 1 were used, the radiation-sensitive resin compositions (J-2) to (J-13) and (CJ-1) were obtained in the same manner as in Example 8. (CJ-6).

<Evaluation>

Using each of the prepared radiation-sensitive resin compositions, the following evaluations were performed. The evaluation results are systematically shown in Table 1.

[LWR performance]

A photoresist underlayer film-forming composition (ARC66, manufactured by Nissan Chemical Industries) was coated on the surface of a 12-inch silicon wafer by selective transfer coating. Next, baking was performed at 205 ° C. for 60 seconds to form a photoresist underlayer film having a film thickness of 105 nm. On the photoresist film, each of the radiation-sensitive resin compositions prepared as described above was spin-coated, and PB was performed at 100 ° C. for 50 seconds, and then cooled at 23 ° C. for 30 seconds to form a 90 nm-thick photoresist film. Next, using a ArF liquid immersion exposure device (S610C, manufactured by NIKON), under the optical conditions of NA: 1.30, Outerσ / innerσ = 0.977 / 0.782, Dipole, and v polarized illumination, a BrightField image of 40nm line / 80nm pitch is projected Use the mask for exposure. Thereafter, PEB was performed at 105 ° C for 50 seconds using a hot plate. Next, using a GP nozzle of a developing unit, a 2.38% by mass tetramethylammonium hydroxide aqueous solution was used as a developing solution to carry out liquid development for 10 seconds, and rinsed with ultrapure water. The substrate with the photoresist pattern formed was obtained by spin drying at 2,000 rpm and 15 seconds of shaking. At this time, the exposure amount that can form a photoresist pattern with a 40nm line / 80nm pitch is set as the optimal exposure amount, and this optimal exposure amount is set as the sensitivity (mJ / cm ² ). Using a length-measuring SEM (CG4000, manufactured by Hitachi), observe the photoresist pattern of the 40nm line / 80nm pitch that is resolved under the optimal exposure from the upper part of the pattern, and measure the line width at ten points at any given point. The distribution of this measured value is made into a value represented by 3σ, and it is set to LWR (nm). The smaller the value, the better the uniformity of the line width of the pattern after development.

It is clear from the results in Table 1 that the LWR of the photoresist pattern formed by the radiation-sensitive resin composition is excellent.

[Industrial availability]

According to the radiation-sensitive resin composition and the photoresist pattern forming method of the present invention, a photoresist pattern having a small LWR can be formed. The acid generating system of the present invention can be suitably used as a component of a radiation-sensitive resin composition and can improve its LWR performance. The compound of the present invention can be suitably used as the acid generator. Therefore, these can be suitably used in a lithography step such as a semiconductor manufacturing process where further miniaturization is expected in the future.

Claims (10)

A radiation-sensitive resin composition comprising a polymer having a structural unit containing an acid dissociable group and an acid generator; the acid generator includes a compound represented by the following formula (2), In formula (2), Z is a base represented by the following formula (1-1) or (1-2); X is a linking group of (n + 1) valence; n is an integer of 1 to 3; n is 1 When X is -O-, -COO-, -NR-, -CONH-, -S-, -SO ₂ -or -SO _3- , R is a monovalent hydrocarbon group; R ⁵ is selected from hydroxyl and carboxyl groups Heteroatom-containing groups substituted with at least one or more substituents of oxyalkyl, carbonyloxyhydrocarbyl, fluorenyl, fluorenyloxy, cyano, nitro, and keto (= O), or include a lactone structure When n is 2 or more, the plural R ⁵ may be the same or different; Z, X, and R ⁵ may also represent a ring structure formed by combining two or more of these; In the formulae (1-1) and (1-2), R ¹ and R ² are each independently a hydrogen atom or a monovalent electron-donating group; R ³ is a monovalent electron-withdrawing group; R ⁴ is a hydrogen atom or 1 R ¹ to R ⁴ may also represent a ring structure in which two or more of these are bonded to each other and together with the carbon atoms bonded thereto; M ⁺ is a monovalent radiation-decomposable onium cation. For example, the radiation-sensitive resin composition of claim 1, wherein n in the formula (2) is 1, and the linking group of the X is -O-, -COO-, -NR-, -CONH-, -S-, -SO ₂ -or -SO _3- , and R is a monovalent hydrocarbon group. The radiation-sensitive resin composition according to claim 1, wherein the compound is a polymer having a structural unit represented by the following formula (3). In formula (3), Z is a group represented by the above formula (1-1) or (1-2); Y is a divalent linking group; R ⁶ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group ; Z and Y can also represent the ring structure constituted by these mutual combinations. The radiation-sensitive resin composition according to any one of claim 1 to claim 3, wherein the aforementioned electron-donating group is a hydrocarbon group, an oxyhydrocarbon group, or an amine group. The radiation-sensitive resin composition according to claim 4, wherein the electron withdrawing group is a cyano group, a fluorine atom or a fluorinated hydrocarbon group. The radiation-sensitive resin composition according to any one of claim 1 to claim 3, wherein the radiation-decomposable onium cation is a sulfonium cation or a sulfonium cation. The radiation-sensitive resin composition according to any one of claim 1 to claim 3, wherein the structural unit containing the acid-dissociable group is represented by the following formula (4); In formula (4), R ⁷ is a hydrogen atom, a fluorine atom, a methyl group, or a trifluoromethyl group; R ⁸ is a monovalent hydrocarbon group having a carbon number of 1 to 20; R ⁹ and R ¹⁰ are each independently a carbon number of 1 to A monovalent chain hydrocarbon group of 10 or a monovalent alicyclic hydrocarbon group having 3 to 20 carbon atoms, or these groups are combined with each other to form an alicyclic carbon group with 3 to 20 carbon atoms. structure. A photoresist pattern forming method includes a step of forming a photoresist film, a step of exposing the photoresist film, and a step of developing the exposed photoresist film, and the photoresist film is as described in item 1 A radiation-sensitive resin composition according to any one of claims 7 to 7. An acid generator comprising a compound represented by the following formula (2), In formula (2), Z is a base represented by the following formula (1-1) or (1-2); X is a linking group of (n + 1) valence; n is an integer of 1 to 3; n is 1 When X is -O-, -COO-, -NR-, -CONH-, -S-, -SO ₂ -or -SO _3- , R is a monovalent hydrocarbon group; R ⁵ is selected from hydroxyl and carboxyl groups Heteroatom-containing groups substituted with at least one or more substituents of oxyalkyl, carbonyloxyalkyl, fluorenyl, fluorenyl, cyano, nitro, and keto (= O) When n is 2 or more, the plural R ⁵ may be the same or different; Z, X, and R ⁵ may also represent a ring structure formed by combining two or more of these; In the formulae (1-1) and (1-2), R ¹ and R ² are each independently a hydrogen atom or a monovalent electron-donating group; R ³ is a monovalent electron-withdrawing group; R ⁴ is a hydrogen atom or 1 R ¹ to R ⁴ may also represent a ring structure in which two or more of these are bonded to each other and together with the carbon atoms bonded thereto; M ⁺ is a monovalent radiation-decomposable onium cation. A compound which is shown in the following (2), In formula (2), Z is a base represented by the following formula (1-1) or (1-2); X is a linking group of (n + 1) valence; n is an integer of 1 to 3; n is 1 When X is -O-, -COO-, -NR-, -CONH-, -S-, -SO ₂ -or -SO _3- , R is a monovalent hydrocarbon group; R ⁵ is selected from hydroxyl and carboxyl groups Heteroatom-containing groups substituted with at least one or more substituents of oxyalkyl, carbonyloxyhydrocarbyl, fluorenyl, fluorenyloxy, cyano, nitro, and keto (= O), or include a lactone structure When n is 2 or more, the plural R ⁵ may be the same or different; Z, X, and R ⁵ may also represent a ring structure formed by combining two or more of these; In the formulae (1-1) and (1-2), R ¹ and R ² are each independently a hydrogen atom or a monovalent electron-donating group; R ³ is a monovalent electron-withdrawing group; R ⁴ is a hydrogen atom or 1 R ¹ to R ⁴ may also represent a ring structure in which two or more of these are bonded to each other and together with the carbon atoms bonded thereto; M ⁺ is a monovalent radiation-decomposable onium cation.