JP7764385B2 - Active energy ray-sensitive acid generator - Google Patents

Description

First, the present invention relates to an actinic ray-sensitive acid generator, more specifically a sulfonium salt-based actinic ray-sensitive acid generator. Second, the present invention relates to an actinic ray-curable composition, a chemically amplified positive-tone photoresist composition, and a chemically amplified negative-tone photoresist composition that contain the acid generator.

Onium salts such as sulfonium salts have been known as cationic polymerization initiators that cure cationic polymerizable compounds upon exposure to active energy rays such as light or electron beams. Photoacid generators that generate acid are also known (Patent Documents 1 to 3). These onium salts are also called acid generators because they generate acid upon exposure to active energy rays, and are used in resists and photosensitive materials (Patent Documents 4 to 6).

The actinic ray-sensitive acid generators described in these specifications, particularly the sulfonium salts, are produced using known methods (Patent Documents 1 and 3). However, the sulfonium salts produced by these methods have problems with their reactivity to actinic rays (i.e., the amount of acid generated), and when incorporated into actinic ray-curable compositions, they suffer from poor long-term storage stability due to the by-product bissulfonium salt and decomposition over time. To solve these problems, improvements to the production method have been reported that suppress the by-production of bissulfonium salt, which was a cause of poor storage stability, but even these improvements did not achieve sufficient long-term storage stability (Patent Document 7).

Japanese Unexamined Patent Publication No. 55-125105 Japanese Unexamined Patent Publication No. 61-190524 Japanese Patent Application Laid-Open No. 61-212554 Japanese Patent Application Laid-Open No. 2002-193925 Japanese Patent Application Publication No. 2001-354669 Japanese Patent Application Publication No. 2001-294570 WO2005/000801 publication

Against this background, the first object of the present invention is to provide a highly active actinic ray-sensitive acid generator that exhibits cationic polymerization and crosslinking reaction properties upon exposure to actinic ray, and in which curable compositions using this acid generator have good storage stability. The second object of the present invention is to provide an actinic ray-curable composition, a chemically amplified positive-tone photoresist composition, and a chemically amplified negative-tone photoresist composition that utilize the acid generator.

The present inventors have discovered an actinic ray-sensitive acid generator suitable for the above-mentioned purpose. Specifically, the present invention relates to an actinic ray-sensitive acid generator (hereinafter referred to as a photoacid generator or acid generator) that contains a sulfonium salt (A) represented by the following general formula (1) and a sulfonium salt (B) represented by the following general formula (2), in which the content of sulfonium salt (B) is 0.01 to 2 mol % relative to the total number of moles of sulfonium salt (A) and sulfonium salt (B).

[In formula (1), R ¹ to R ⁴ are organic groups bonded to a benzene ring; the number of R ² is 0 to 4, the numbers of R ¹ , R ³ , and R ⁴ are 0 to 5, and when R 2 is 0, a hydrogen atom is bonded; when a plurality of R ¹ to R ⁴ are bonded, they may be the same or different; and R ¹ to R ⁴ may form a ring structure either directly or via —O—, —S—, —SO—, —SO ₂ —, —NH—, —CO—, —COO—, —CONH—, an alkylene group, or a phenylene group; and X ⁻ is a monovalent anion having an element of Group 13 or 15 of the periodic table and having a halogen atom]

[In formula (2), R ¹ to R ⁴ are organic groups bonded to a benzene ring, the number of R ² is 0 to 4, the numbers of R ¹ , R ³ , and R ⁴ are 0 to 5, and when R 2 is 0, a hydrogen atom is bonded, and when a plurality of R ¹ to R ⁴ are bonded, they may be the same or different, and R ¹ to R ⁴ may form a ring structure with each other directly or via -O-, -S-, -SO-, -SO ₂ -, -NH-, -CO-, -COO-, -CONH-, an alkylene group, or a phenylene group, and Y ^- is a monovalent anion selected from the group consisting of anions not having a halogen]

The present invention also relates to an active energy ray-curable composition containing the above-mentioned acid generator and a cationically polymerizable compound; a cured product obtained by curing the above-mentioned active energy ray-curable composition; a chemically amplified positive photoresist composition containing the above-mentioned acid generator and component (B), which is a resin whose solubility in alkali increases under the action of acid; a chemically amplified negative photoresist composition containing the above-mentioned acid generator, component (F), which is an alkali-soluble resin having a phenolic hydroxyl group, and crosslinker component (G); and a cured product obtained by curing the above-mentioned chemically amplified negative photoresist composition.

The acid generator of the present invention has high activity against active energy rays, and also has cationic polymerization and crosslinking reaction properties, and compositions using this have good storage stability.

The following describes in detail an embodiment of the present invention.

R ¹ to R ⁴ in formula (1) or (2) represent organic groups bonded to a benzene ring and may be the same or different. R ¹ to R ⁴ represent an aryl group having 6 to 30 carbon atoms, a heterocyclic group having 4 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, or an alkynyl group having 2 to 30 carbon atoms, which may be substituted with at least one group selected from the group consisting of alkyl, hydroxy, alkoxy, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aryloxycarbonyl, arylthiocarbonyl, acyloxy, arylthio, alkylthio, aryl, heterocyclic, aryloxy, alkylsulfinyl, arylsulfinyl, alkylsulfonyl, arylsulfonyl, alkyleneoxy, amino, cyano, nitro, and halogen.

In the above, aryl groups having 6 to 30 carbon atoms include monocyclic aryl groups such as phenyl and biphenylyl groups, and condensed polycyclic aryl groups such as naphthyl, anthracenyl, phenanthrenyl, pyrenyl, chrysenyl, naphthacenyl, benzanthracenyl, anthraquinonyl, naphthoquinonyl, and fluorenyl.

Heterocyclic groups having 4 to 30 carbon atoms include rings containing 1 to 3 heteroatoms, such as oxygen, nitrogen, or sulfur, which may be the same or different. Specific examples include monocyclic heterocyclic groups such as thienyl, furanyl, pyranyl, pyrrolyl, oxazolyl, thiazolyl, pyridyl, pyrimidyl, and pyrazinyl, and fused polycyclic heterocyclic groups such as indolyl, benzofuranyl, isobenzofuranyl, benzothienyl, isobenzothienyl, quinolyl, isoquinolyl, quinoxalinyl, quinazolinyl, carbazolyl, acridinyl, phenothiazinyl, phenazinyl, xanthenyl, thianthrenyl, phenoxazinyl, phenoxathiinyl, chromanyl, isochromanyl, dibenzothienyl, xanthonyl, thioxanthonyl, and dibenzofuranyl.

Examples of the alkyl group having 1 to 30 carbon atoms include linear alkyl groups such as methyl, ethyl, propyl, butyl, hexadecyl, and octadecyl; branched alkyl groups such as isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, and isohexyl; and cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl.
Examples of the alkenyl group having 2 to 30 carbon atoms include straight-chain or branched ones such as vinyl, allyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, and 1-methyl-1-propenyl.
Furthermore, examples of the alkynyl group having 2 to 30 carbon atoms include straight-chain or branched ones such as ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-methyl-1-propynyl, and 1-methyl-2-propynyl.

The above-mentioned aryl groups having 6 to 30 carbon atoms, heterocyclic groups having 4 to 30 carbon atoms, alkyl groups having 1 to 30 carbon atoms, alkenyl groups having 2 to 30 carbon atoms, or alkynyl groups having 2 to 30 carbon atoms may have at least one substituent. Examples of the substituent include linear alkyl groups having 1 to 18 carbon atoms, such as methyl, ethyl, propyl, butyl, and octadecyl; isopropyl, isobutyl, etc. branched alkyl groups having 1 to 18 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; cycloalkyl groups having 3 to 18 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; hydroxy groups; linear or branched alkoxy groups having 1 to 18 carbon atoms such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, and dodecyloxy; linear or branched alkylcarbonyl groups having 2 to 18 carbon atoms such as acetyl, propionyl, butanoyl, 2-methylpropionyl, heptanoyl, 2-methylbutanoyl, 3-methylbutanoyl, and octanoyl; arylcarbonyl groups having 7 to 11 carbon atoms such as benzoyl and naphthoyl; linear or branched alkoxycarbonyl groups having 2 to 19 carbon atoms, such as alkoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, and tert-butoxycarbonyl; aryloxycarbonyl groups having 7 to 11 carbon atoms, such as phenoxycarbonyl and naphthoxycarbonyl; arylthiocarbonyl groups having 7 to 11 carbon atoms, such as phenylthiocarbonyl and naphthoxythiocarbonyl; acetoxy, ethylcarbonyloxy, propylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, tert-butylcarbonyloxy, and octadecylcarbonyloxy; linear or branched acyloxy groups having 2 to 19 carbon atoms, such as phenylthio, biphenylylthio, methylphenylthio, chlorophenylthio, bromophenylthio, fluorophenylthio, hydroxyphenylthio, methoxyphenylthio, naphthylthio, 4-[4-(phenylthio)benzoyl]phenylthio, 4-[4-(phenylthio)phenoxy]phenylthio, 4-[4-(phenylthio)phenyl]phenylthio, 4-(phenylthio)phenylthio, 4-benzoylphenylthio, 4-benzoyl-chlorophenylthio, 4-benzoyl-methylthiophenylthio, 4-(methylthiobenzoyl)phenylthio, 4-(p-tert-butylbenzoyl)phenylthio, and other arylthio groups having 6 to 20 carbon atoms, such as methylthio, ethylthio, propylthio, tert-butylthio, neopentylthio, dodecylthio, and the like; linear or branched alkylthio groups having 1 to 18 carbon atoms, such as ruthio; aryl groups having 6 to 10 carbon atoms, such as phenyl, tolyl, dimethylphenyl, and naphthyl; heterocyclic groups having 4 to 20 carbon atoms, such as thienyl, furanyl, pyranyl, xanthenyl, chromanyl, isochromanyl, xanthonyl, thioxanthonyl, and dibenzofuranyl; aryloxy groups having 6 to 10 carbon atoms, such as phenoxy and naphthyloxy; linear or branched alkylthio groups having 1 to 18 carbon atoms, such as methylsulfinyl, ethylsulfinyl, propylsulfinyl, tert-pentylsulfinyl, and octylsulfinyl. or branched alkylsulfinyl groups; arylsulfinyl groups having 6 to 10 carbon atoms such as phenylsulfinyl, tolylsulfinyl, and naphthylsulfinyl; linear or branched alkylsulfonyl groups having 1 to 18 carbon atoms such as methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl, and octylsulfonyl; arylsulfonyl groups having 6 to 10 carbon atoms such as phenylsulfonyl, tolylsulfonyl (tosyl group), and naphthylsulfonyl; alkyleneoxy groups; cyano groups; nitro groups; and halogens such as fluorine, chlorine, bromine, and iodine.

When multiple R ¹ to R ⁴ are bonded together, they may form a ring structure either directly or via -O-, -S-, -SO-, -SO ₂ -, -NH-, -CO-, -COO-, -CONH-, an alkylene group or a phenylene group. For example, when there are two or more R ^1s , it means that two of the R ^1s form a ring structure either directly or via -O-, -S-, -SO-, -SO ₂ -, -NH-, -CO-, -COO-, -CONH-, an alkylene group or a phenylene group.

Of these organic groups, preferred are alkyl groups having 1 to 6 carbon atoms, aryl groups having 6 to 14 carbon atoms, hydroxy groups, alkoxy groups having 1 to 6 carbon atoms, alkylthio groups having 1 to 6 carbon atoms, arylthio groups having 6 to 14 carbon atoms, aryloxy groups having 6 to 10 carbon atoms, chlorine atoms, and fluorine atoms, and more preferred are alkyl groups having 1 to 6 carbon atoms, aryl groups having 6 to 14 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms.

The number of R ¹ to R ^4, which are the substituents in formula (1) or (2), is 0 to 5, and when the number is 0, a hydrogen atom is bonded. The number of R ¹ to R ⁴ is preferably 0 to 3, and more preferably 0 or 1. When the numbers of ^{R 1} to R ⁴ are within these preferred ranges, the photosensitivity and solubility of the sulfonium salt are good.

Specific examples of preferred cation moieties among the sulfonium salts represented by formula (1) or (2) are shown below.

In formula (1), ^X- is an atom (group) capable of becoming a monovalent anion, i.e., an anion corresponding to an acid (HX) generated by irradiating a sulfonium salt with active energy rays (visible light, ultraviolet light, electron beam, X-ray, etc. ⁾ . ^X- is not limited except that it is a monovalent polyatomic anion containing an element of Group 13 or 15 of the periodic table and a halogen atom, but anions represented by _MZ- , (Rf) _{bPF6 -b-} ^{, R8cBZ4} _{-c- ,} ^{R8cGaZ4 -} _{c- ,} ^or ( ^R9SO2 _{) 2N-} ^are preferred from the viewpoint of photosensitivity.

M represents a phosphorus atom, a boron atom, or an antimony atom.
Z represents a halogen atom (preferably a fluorine atom).

Rf represents an alkyl group (preferably an alkyl group having 1 to 8 carbon atoms) in which 80 mol % or more of the hydrogen atoms have been substituted with fluorine atoms. Examples of alkyl groups that are substituted with fluorine atoms to form Rf include linear alkyl groups (methyl, ethyl, propyl, butyl, pentyl, octyl, etc.), branched alkyl groups (isopropyl, isobutyl, sec-butyl, tert-butyl, etc.), and cycloalkyl groups (cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.). The proportion of hydrogen atoms in these alkyl groups substituted with fluorine atoms in Rf is preferably 80 mol % or more, more preferably 90% or more, and particularly preferably 100%, based on the number of moles of hydrogen atoms originally possessed by the alkyl group. When the substitution ratio with fluorine atoms is within these preferred ranges, the photosensitivity of the sulfonium salt is further improved. Particularly preferred Rf's include _CF3- , _CF3CF2- , ( _CF3 ) _2CF- , _{CF3CF2CF2- , CF3CF2CF2CF2-} , _{( CF3 ) 2CFCF2- , CF3CF2} ( _{CF3 ) CF-} and ( _CF3 ) _3C- . The b Rf's _are independent of each other and _may therefore be the same or different.

P represents a phosphorus atom and F represents a fluorine atom.

^R8 represents a phenyl group in which a portion of the hydrogen atoms is substituted with at least one element or electron-withdrawing group. Examples of such an element include a halogen atom, such as a fluorine atom, a chlorine atom, and a bromine atom. Examples of the electron-withdrawing group include a trifluoromethyl group, a nitro group, and a cyano group. Of these, a phenyl group in which one hydrogen atom is substituted with a fluorine atom or a trifluoromethyl group is preferred. The c ^R8s are mutually independent and may therefore be the same or different.

B represents a boron atom and Ga represents a gallium atom.

R ⁹ represents a perfluoroalkyl group having 1 to 20 carbon atoms or a perfluoroaryl group having 6 to 20 carbon atoms, and the perfluoroalkyl group may be straight-chain, branched-chain or cyclic.

S represents a sulfur atom, O represents an oxygen atom, C represents a carbon atom, and N represents a nitrogen atom. a represents an integer from 4 to 6. b is preferably an integer from 1 to 5, more preferably 2 to 4, and particularly preferably 2 or 3. c is preferably an integer from 1 to 4, more preferably 4.

Examples of the anion represented by MZ _a ^- include anions represented by SbF ₆ ^- , PF ₆ ^- and BF ₄ ^- .

Examples of the anion represented by (Rf) _b PF _6-b ^- include (CF ₃ CF ₂ ) ₂ PF ₄ ^- , (CF ₃ CF ₂ ) ₃ PF ₃ ^- , ((CF ₃ ) ₂ CF) ₂ PF ₄ ^- , ((CF ₃ ) ₂ CF) ₃ PF ₃ ^- , (CF ₃ CF ₂ CF ₂ ) ₂ PF ₄ ^- , (CF ₃ CF ₂ CF ₂ ) ₃ PF ₃ ^- , ((CF ₃ ) ₂ CFCF ₂ ) ₂ PF ₄ ^- , ((CF ₃ ) ₂ CFCF ₂ ) ₃ PF ₃ ^- , (CF ₃ CF ₂ CF ₂ CF ₂ ) ₂ PF ₄ ^-- and (CF ₃ CF ₂ CF ₂ CF ₂ ) ₃ PF ₃ ^-- . Among these, anions represented by (CF ₃ CF ₂ ) ₃ PF ₃ ^-- , (CF ₃ CF ₂ CF ₂ ) ₃ PF ₃ ^-- , ((CF ₃ ) ₂ CF) ₃ PF ₃ ^-- , ((CF ₃ ) ₂ CF) ₂ PF ₄ ^-- , ((CF ₃ ) ₂ CFCF ₂ ) ₃ PF ₃ ^-- and ((CF ₃ ) ₂ CFCF ₂ ) ₂ PF ₄ ^-- are preferred.

Examples of the anion represented by R ⁸ _c BZ _4-c ^- include anions represented by (C ₆ F ₅ ) ₄ B ^- , ((CF ₃ ) ₂ C ₆ H ₃ ) ₄ B ^- , (CF ₃ C ₆ H ₄ ) ₄ B ^- , (C ₆ F ₅ ) ₂ BF ₂ ^- , C ₆ F ₅ BF ₃ ^- and (C ₆ H ₃ F ₂ ) ₄ B ^- . Of these, anions represented by (C ₆ F ₅ ) ₄ B ^- and ((CF ₃ ) ₂ C ₆ H ₃ ) ₄ B ^- are preferred.

Examples of the anion represented by R ⁸ _c GaZ _4-c ^- include anions represented by (C ₆ F ₅ ) ₄ Ga ^- , ((CF ₃ ) ₂ C ₆ H ₃ ) ₄ Ga ^- , (CF ₃ C ₆ H ₄ ) ₄ Ga ^- , (C ₆ F ₅ ) ₂ GaF ₂ ^- , C ₆ F ₅ GaF ₃ ^- and (C ₆ H ₃ F ₂ ) ₄ Ga ^- . Of these, anions represented by (C ₆ F ₅ ) ₄ Ga ^- and ((CF ₃ ) ₂ C ₆ H ₃ ) ₄ Ga ^- are preferred.

Of these X ^{− s} , anions represented by MZ _a ⁻ , (Rf) _b PF _6-b ⁻ , R ⁸ _c BZ _4-c ⁻ , R ⁸ _c GaZ _4-c ⁻ , R ⁹ SO ₃ ⁻ , or (R ⁹ SO ₂ ) ₂ N ⁻ are preferred, and SbF ₆ ⁻ , PF ₆ ⁻ , (CF ₃ CF ₂ ) ₃ PF ₃ ⁻ , ((CF ₃ ) ₂ CF) ₃ PF ₃ ⁻ , (CF ₃ CF ₂ CF ₂ ) ₃ PF ₃ ⁻ , (C ₆ F ₅ ) ₄ B ⁻ , ((CF ₃ ) ₂ C ₆ H ₃ ) ₄ B ⁻ , (C ₆ F ₅ ) ₄ Ga ⁻ , ((CF ₃ ) ₂ C ₆ H ₃ ) ₄ Ga ⁻ , and (CF ₃ SO ₂ ) ₂ N ⁻ are more preferred in that they improve the resist resolution and pattern shape, and (CF ₃ CF ₂ ) ₃ PF ₃ ⁻ , ((CF ₃ ) ₂ CF) ₃ PF ₃ ⁻ , (CF ₃ CF ₂ CF ₂ ) ₃ PF ₃ ⁻ , (C ₆ F ₅ ) ₄ B ⁻ and ((CF ₃ ) ₂ C ₆ H ₃ ) ₄ B ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ are particularly preferred because they have better compatibility with the resist composition.

In formula (2), Y ⁻ is a monovalent anion selected from the group consisting of anions containing no halogen, and the atom (group) that can become the monovalent anion is preferably selected from the group consisting of HSO ₄ ⁻ , HNO ₃ ⁻ , H ₂ PO ₄ ⁻ , a methanesulfonate anion, a carboxylate anion containing no halogen, and an anion represented by the following general formula (3):

[In formula (3), R ⁵ and R ⁶ are hydrogen atoms or organic groups, the number of R 5 and R ⁶ is 0 to 5, and when R ⁵ and R ⁶ are 0, a hydrogen atom is bonded, and when a plurality of R ⁵ and R 6 are bonded, they may be the same or different, and R ⁵ and R ⁶ may form a ring structure with each other directly or via -O-, -S-, -SO-, -SO ₂ -, -NH-, -CO-, -COO-, -CONH-, an alkylene group or a phenylene group, and m and n are each 0 or 1, and m+n=1.]

Examples of halogen-free carboxylic acids include formic acid, glycolic acid, acetic acid, propionic acid, butyric acid, valeric acid, octylic acid, 2-ethylhexanoic acid, cyanoacetic acid, trimethylacetic acid, methoxyacetic acid, cyclopentanecarboxylic acid, mercaptoacetic acid, lactic acid, pyruvic acid, levulinic acid, acrylic acid, crotonic acid, vinylacetic acid, methacrylic acid, anisic acid, benzoic acid, cinnamic acid, naphthoic acid, phenylacetic acid, phenoxyacetic acid, and mandelic acid.

^R5 and ^R6 in formula (3) represent organic groups bonded to the benzene ring and may be the same or different. ^R5 and ^R6 represent an aryl group having 6 to 30 carbon atoms, a heterocyclic group having 4 to 30 carbon atoms, an alkyl group having 1 to 30 carbon atoms, an alkenyl group having 2 to 30 carbon atoms, or an alkynyl group having 2 to 30 carbon atoms, which may be substituted with at least one selected from the group consisting of alkyl, hydroxy, alkoxy, alkylcarbonyl, arylcarbonyl, alkoxycarbonyl, aryloxycarbonyl, arylthiocarbonyl, acyloxy, arylthio, alkylthio, aryl, heterocyclic, aryloxy, alkylsulfinyl, arylsulfinyl, alkylsulfonyl, arylsulfonyl, alkyleneoxy, amino, cyano, nitro, and halogen.

The aryl group having 6 to 30 carbon atoms is the same as the specific examples of the aryl group having 6 to 30 carbon atoms given above as R ¹ to R ⁴ .

Examples of the heterocyclic group having 4 to 30 carbon atoms are the same as the specific examples of the heterocyclic group having 4 to 30 carbon atoms given above as R ¹ to R ⁴ .

The alkyl group having 1 to 30 carbon atoms is the same as the specific examples of the alkyl group having 1 to 30 carbon atoms given above as R ¹ to R ⁴ .
Furthermore, the alkenyl group having 2 to 30 carbon atoms is the same as the specific examples of the alkenyl group having 2 to 30 carbon atoms given as R ¹ to R ⁴ above.
Furthermore, examples of the alkynyl group having 2 to 30 carbon atoms are the same as the specific examples of the alkynyl group having 2 to 30 carbon atoms given as R ¹ to R ⁴ above.

The above-mentioned aryl groups having 6 to 30 carbon atoms, heterocyclic groups having 4 to 30 carbon atoms, alkyl groups having 1 to 30 carbon atoms, alkenyl groups having 2 to 30 carbon atoms, and alkynyl groups having 2 to 30 carbon atoms may have at least one substituent. Examples of the substituent include linear alkyl groups having 1 to 18 carbon atoms, such as methyl, ethyl, propyl, butyl, and octadecyl; isopropyl, and isobutyl. branched alkyl groups having 1 to 18 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; cycloalkyl groups having 3 to 18 carbon atoms such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl; hydroxy groups; linear or branched alkoxy groups having 1 to 18 carbon atoms such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, and dodecyloxy; linear or branched alkylcarbonyl groups having 2 to 18 carbon atoms such as acetyl, propionyl, butanoyl, 2-methylpropionyl, heptanoyl, 2-methylbutanoyl, 3-methylbutanoyl, and octanoyl; arylcarbonyl groups having 7 to 11 carbon atoms such as benzoyl and naphthoyl; linear or branched alkoxycarbonyl groups having 2 to 19 carbon atoms, such as alkoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, and tert-butoxycarbonyl; aryloxycarbonyl groups having 7 to 11 carbon atoms, such as phenoxycarbonyl and naphthoxycarbonyl; arylthiocarbonyl groups having 7 to 11 carbon atoms, such as phenylthiocarbonyl and naphthoxythiocarbonyl; acetoxy, ethylcarbonyloxy, propylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, tert-butylcarbonyloxy, and octadecylcarbonyloxy; linear or branched acyloxy groups having 2 to 19 carbon atoms, such as phenylthio, biphenylylthio, methylphenylthio, chlorophenylthio, bromophenylthio, fluorophenylthio, hydroxyphenylthio, methoxyphenylthio, naphthylthio, 4-[4-(phenylthio)benzoyl]phenylthio, 4-[4-(phenylthio)phenoxy]phenylthio, 4-[4-(phenylthio)phenyl]phenylthio, 4-(phenylthio)phenylthio, 4-benzoylphenylthio, 4-benzoyl-chlorophenylthio, 4-benzoyl-methylthiophenylthio, 4-(methylthiobenzoyl)phenylthio, 4-(p-tert-butylbenzoyl)phenylthio, and other arylthio groups having 6 to 20 carbon atoms, such as methylthio, ethylthio, propylthio, tert-butylthio, neopentylthio, dodecylthio, and the like; linear or branched alkylthio groups having 1 to 18 carbon atoms, such as ruthio; aryl groups having 6 to 10 carbon atoms, such as phenyl, tolyl, dimethylphenyl, and naphthyl; heterocyclic groups having 4 to 20 carbon atoms, such as thienyl, furanyl, pyranyl, xanthenyl, chromanyl, isochromanyl, xanthonyl, thioxanthonyl, and dibenzofuranyl; aryloxy groups having 6 to 10 carbon atoms, such as phenoxy and naphthyloxy; linear or branched alkylthio groups having 1 to 18 carbon atoms, such as methylsulfinyl, ethylsulfinyl, propylsulfinyl, tert-pentylsulfinyl, and octylsulfinyl; arylsulfinyl groups having 6 to 10 carbon atoms, such as phenylsulfinyl, tolylsulfinyl, and naphthylsulfinyl; linear or branched alkylsulfonyl groups having 1 to 18 carbon atoms, such as methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl, and octylsulfonyl; arylsulfonyl groups having 6 to 10 carbon atoms, such as phenylsulfonyl, tolylsulfonyl (tosyl group), and naphthylsulfonyl; alkyleneoxy groups; cyano groups; and nitro groups.

R ⁵ and R ⁶ may form a ring structure either directly or via —O—, —S—, —SO—, —SO ₂ —, —NH—, —CO—, —COO—, —CONH—, an alkylene group or a phenylene group.

Of these organic groups, preferred are alkyl groups having 1 to 6 carbon atoms, aryl groups having 6 to 14 carbon atoms, hydroxy groups, alkoxy groups having 1 to 6 carbon atoms, alkylthio groups having 1 to 6 carbon atoms, arylthio groups having 6 to 14 carbon atoms, aryloxy groups having 6 to 10 carbon atoms, chlorine atoms, and fluorine atoms, and more preferred are alkyl groups having 1 to 6 carbon atoms, aryl groups having 6 to 14 carbon atoms, and alkoxy groups having 1 to 6 carbon atoms.

In formula (3), m and n are each 0 or 1, and m+n=1.

Of these Y 1 ^- groups, HSO ₄ ^- and the compounds represented by general formula (3) are preferred from the viewpoint of storage stability.

From the viewpoint of storage stability, ^R5 or ^R6 in formula (3) is preferably an arylthio group or an arylsulfinyl group.

From the viewpoint of solubility in resist, the following structure is even more preferred for formula (3).

The content of sulfonium salt (B) is 0.01 to 2 mol% relative to the total number of moles of sulfonium salt (A) represented by general formula (1) and sulfonium salt (B) represented by general formula (2). A content of 0.01 mol% or more improves storage stability, while a content exceeding 2 mol% degrades the curability of cationic polymerization and the sensitivity of the resist. From the standpoint of storage stability, 0.1 to 2 mol% is preferable.

Sulfonium salt (A) represented by general formula (1) and sulfonium salt (B) represented by general formula (2) can be produced by known production methods, such as reacting diaryl sulfide with chlorine, reacting diaryl sulfide with chlorine and an aromatic hydrocarbon such as benzene, or reacting diaryl sulfide with diaryl sulfoxide in the presence of a dehydrating agent.

There are no particular limitations on the dehydrating agent, and any agent that is used as a dehydrating agent in organic chemical reactions can be used. Examples include concentrated sulfuric acid, phosphoric anhydride, methanesulfonic acid, acetic anhydride, trifluoromethanesulfonic acid, or its anhydride. Two or more of these may be mixed and used. A solvent may also be used as appropriate.

When diaryl sulfoxide and diaryl sulfide are reacted in the presence of a dehydrating agent, the molar ratio of sulfoxide to sulfide is 10:1 to 1:1, more preferably 7:1 to 2:1, and most preferably 5:1 to 2.5:1. The reaction temperature is -10°C to 50°C, preferably -5°C to 30°C, and most preferably 0°C to 10°C. By carrying out the reaction under these conditions, the sulfonium salt of the present invention can be produced with high purity.

After the reaction, sulfonium salts can be efficiently produced by exchanging the anion with an acid (HX) and salt (AXn) having the anion represented by X in formula (1). Here, A is the counter cation of the anion X-, and n represents the number of anions X relative to the valence of the cation A. A represents an alkali metal such as Na, K, or Li, an alkaline earth metal such as Mg or Ca, or an ammonium cation. Alkali metals are more preferred due to the ease of obtaining raw materials and the ease of purifying the sulfonium salt produced.

Similarly, sulfonium salts can be efficiently produced by exchanging anions with an acid (HY) and a salt (AYn) having an anion represented by Y in general formula (2).

The acid generator of the present invention can be produced by mixing sulfonium salts of general formulas (1) and (2), and the content of sulfonium salt (B) is 0.01 to 2 mol % relative to the total number of moles of sulfonium salt (A) represented by general formula (1) and sulfonium salt (B) represented by general formula (2).

In addition to the sulfonium salts listed above, the acid generator of the present invention may contain other conventionally known acid generators, if necessary. Note that, below, the acid generator of the present invention consists of the sulfonium salts represented by formulas (1) and (2), and does not include other acid generators.

When other acid generators are contained, the content of the other acid generators is preferably 0.1 to 100 moles, more preferably 0.5 to 50 moles, relative to the total number of moles of the sulfonium salts represented by formulas (1) and (2) of the present invention.

Other acid generators include conventionally known onium salts (sulfonium, iodonium, selenium, ammonium, phosphonium, etc.) and salts of transition metal complex ions and anions.

In order to facilitate dissolution of the acid generator of the present invention in a cationically polymerizable compound or a chemically amplified resist composition, it may be dissolved in advance in a solvent that does not inhibit polymerization, crosslinking, deprotection reactions, etc.

Solvents include carbonates such as propylene carbonate, ethylene carbonate, 1,2-butylene carbonate, dimethyl carbonate, and diethyl carbonate; ketones such as acetone, methyl ethyl ketone, cyclohexanone, methyl isoamyl ketone, and 2-heptanone; polyhydric alcohols and their derivatives such as ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol, and the monomethyl ether, monoethyl ether, monopropyl ether, monobutyl ether, or monophenyl ether of dipropylene glycol monoacetate; cyclic ethers such as dioxane; Examples of the ester include ethyl formate, methyl lactate, ethyl lactate, methyl acetate, ethyl acetate, butyl acetate, methyl pyruvate, methyl acetoacetate, ethyl acetoacetate, ethyl pyruvate, ethyl ethoxyacetate, methyl methoxypropionate, ethyl ethoxypropionate, methyl 2-hydroxypropionate, ethyl 2-hydroxypropionate, ethyl 2-hydroxy-2-methylpropionate, methyl 2-hydroxy-3-methylbutanoate, 3-methoxybutyl acetate, and 3-methyl-3-methoxybutyl acetate; and aromatic hydrocarbons such as toluene and xylene.

When a solvent is used, the proportion of the solvent used is preferably 15 to 1,000 parts by weight, and more preferably 30 to 500 parts by weight, per 100 parts by weight of the acid generator of the present invention. The solvents used may be used alone or in combination of two or more types.

The active energy ray-curable composition of the present invention comprises the above-described acid generator and a cationically polymerizable compound. From the viewpoint of preventing coloration of the cured product, the alkali metal content in the active energy ray-curable composition is preferably 1.5 ppm or less.

Examples of cationically polymerizable compounds that are components of active energy ray-curable compositions include cyclic ethers (epoxides, oxetanes, etc.), ethylenically unsaturated compounds (vinyl ethers, styrenes, etc.), bicycloorthoesters, spiroorthocarbonates, and spiroorthoesters (see JP-A-11-060996, JP-A-09-302269, JP-A-2003-026993, JP-A-2002-206017, JP-A-11-349895, JP-A-10-212343, JP-A-2000-119306, JP-A-10-67812, JP-A-2000-186071, JP-A-08-85775, JP-A-08-134405, JP-A- 2008-20838, JP 2008-20839, JP 2008-20841, JP 2008-26660, JP 2008-26644, JP 2007-277327, "Photopolymer Handbook" edited by the Photopolymer Forum (1989, Industrial Research Institute), "UV/EB Curing Technology" edited by the General Technology Center (1982, General Technology Center), "UV/EB Curing Materials" edited by the RadTech Research Group (1992, CMC), "Causes of Curing Defects and Inhibitions in UV Curing and Countermeasures Therefor" edited by the Technical Information Association (2003, Technical Information Association), Color Materials, 68, (5), 286-293 (1995), Fine Chemicals, 29, (19), 5-14 (2000), etc.

As epoxides, known epoxides can be used, including aromatic epoxides, alicyclic epoxides, and aliphatic epoxides.

Aromatic epoxides include glycidyl ethers of mono- or polyhydric phenols having at least one aromatic ring (phenol, bisphenol A, phenol novolac, and their alkylene oxide adducts).

Examples of alicyclic epoxides include compounds obtained by epoxidizing a compound having at least one cyclohexene or cyclopentene ring with an oxidizing agent (e.g., 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate).

Examples of aliphatic epoxides include polyglycidyl ethers of aliphatic polyhydric alcohols or their alkylene oxide adducts (1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, etc.), polyglycidyl esters of aliphatic polybasic acids (diglycidyl tetrahydrophthalate, etc.), and epoxidized products of long-chain unsaturated compounds (epoxidized soybean oil, epoxidized polybutadiene, etc.).

As the oxetane, known compounds can be used, such as 3-ethyl-3-hydroxymethyloxetane, 2-ethylhexyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxyethyl (3-ethyl-3-oxetanylmethyl) ether, 2-hydroxypropyl (3-ethyl-3-oxetanylmethyl) ether, 1,4-bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, oxetanylsilsesquioxetane, and phenol novolac oxetane.

As the ethylenically unsaturated compound, known cationically polymerizable monomers can be used, including aliphatic monovinyl ethers, aromatic monovinyl ethers, polyfunctional vinyl ethers, styrene, and cationically polymerizable nitrogen-containing monomers.

Aliphatic monovinyl ethers include methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, and cyclohexyl vinyl ether.

Examples of aromatic monovinyl ethers include 2-phenoxyethyl vinyl ether, phenyl vinyl ether, and p-methoxyphenyl vinyl ether.

Examples of polyfunctional vinyl ethers include butanediol-1,4-divinyl ether and triethylene glycol divinyl ether.

Examples of styrene include styrene, α-methylstyrene, p-methoxystyrene, and p-tert-butoxystyrene.

Examples of cationically polymerizable nitrogen-containing monomers include N-vinylcarbazole and N-vinylpyrrolidone.

Bicyclo orthoesters include 1-phenyl-4-ethyl-2,6,7-trioxabicyclo[2.2.2]octane and 1-ethyl-4-hydroxymethyl-2,6,7-trioxabicyclo-[2.2.2]octane.

Examples of spiro orthocarbonates include 1,5,7,11-tetraoxaspiro[5.5]undecane and 3,9-dibenzyl-1,5,7,11-tetraoxaspiro[5.5]undecane.

Examples of spiro orthoesters include 1,4,6-trioxaspiro[4.4]nonane, 2-methyl-1,4,6-trioxaspiro[4.4]nonane, and 1,4,6-trioxaspiro[4.5]decane.

Furthermore, polyorganosiloxanes having at least one cationically polymerizable group per molecule can be used (such as those described in JP 2001-348482 A, JP 2000-281965 A, JP 7-242828 A, JP 2008-195931 A, Journal of Polym. Sci., Part A, Polym. Chem., Vol. 28, 497 (1990)). These polyorganosiloxanes may be linear, branched, or cyclic, or may be mixtures of these.

Of these cationically polymerizable compounds, epoxides, oxetanes, and vinyl ethers are preferred, epoxides and oxetanes are more preferred, and alicyclic epoxides and oxetanes are particularly preferred. These cationically polymerizable compounds may be used alone or in combination of two or more.

The content of the acid generator of the present invention in the active energy ray-curable composition is preferably 0.05 to 20 parts by weight, and more preferably 0.1 to 10 parts by weight, per 100 parts by weight of the cationically polymerizable compound. Within this range, polymerization of the cationically polymerizable compound is more sufficient, resulting in better physical properties of the cured product. Note that this content is determined by taking into consideration various factors such as the properties of the cationically polymerizable compound, the type and dose of active energy rays, temperature, curing time, humidity, and coating thickness, and is not limited to the above range.

The active energy ray-curable composition of the present invention may contain, if necessary, known additives (sensitizers, pigments, fillers, antistatic agents, flame retardants, antifoaming agents, flow control agents, light stabilizers, antioxidants, adhesion promoters, ion scavengers, color inhibitors, solvents, non-reactive resins, and radically polymerizable compounds, etc.).

As a sensitizer, known sensitizers (such as those disclosed in JP-A-11-279212 and JP-A-09-183960) can be used, such as anthracene {anthracene, 9,10-dibutoxyanthracene, 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, 9,10-dipropoxyanthracene, etc.}; pyrene; 1,2-benzanthracene; perylene; tetracene; coronene; thioxanthone {thioxanthone, 2 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, 2,4-diethylthioxanthone, etc.}; phenothiazines {phenothiazine, N-methylphenothiazine, N-ethylphenothiazine, N-phenylphenothiazine, etc.}; xanthone; naphthalenes {1-naphthol, 2-naphthol, 1-methoxynaphthalene, 2-methoxynaphthalene, 1,4-dihydroxynaphthalene, 4-methoxy-1-naphthol, etc.}; ketones {dimethoxyacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4'-isopropyl-2-hydroxy-2-methylpropiophenone, 4-benzoyl-4'-methyldiphenyl sulfide, etc.} carbazole {N-phenylcarbazole, N-ethylcarbazole, poly-N-vinylcarbazole, N-glycidylcarbazole, etc.}; chrysene {1,4-dimethoxychrysene, 1,4-di-α-methylbenzyloxychrysene, etc.}; phenanthrene {9-hydroxyphenanthrene, 9-methoxyphenanthrene, 9-hydroxy-10-methoxyphenanthrene, 9-hydroxy-10-ethoxyphenanthrene, etc.}.

If a sensitizer is contained, the content of the sensitizer is preferably 1 to 300 parts by weight, more preferably 5 to 200 parts by weight, per 100 parts of the acid generator.

Pigments that can be used include known pigments, such as inorganic pigments (titanium oxide, iron oxide, and carbon black) and organic pigments (azo pigments, cyanine pigments, phthalocyanine pigments, and quinacridone pigments).

If a pigment is contained, the pigment content is preferably 0.5 to 400,000 parts by weight per 100 parts of acid generator, and more preferably 10 to 150,000 parts by weight.

As fillers, known fillers can be used, such as fused silica, crystalline silica, calcium carbonate, aluminum oxide, aluminum hydroxide, zirconium oxide, magnesium carbonate, mica, talc, calcium silicate, and lithium aluminum silicate.

If a filler is contained, the content of the filler is preferably 50 to 600,000 parts by weight per 100 parts of acid generator, and more preferably 300 to 200,000 parts by weight.

As the antistatic agent, known antistatic agents can be used, and examples thereof include nonionic antistatic agents, anionic antistatic agents, cationic antistatic agents, amphoteric antistatic agents, and polymeric antistatic agents.

When an antistatic agent is contained, the content of the antistatic agent is preferably 0.1 to 20,000 parts by weight, more preferably 0.6 to 5,000 parts by weight, per 100 parts of the acid generator.

As flame retardants, known flame retardants can be used, such as inorganic flame retardants (antimony trioxide, antimony pentoxide, tin oxide, tin hydroxide, molybdenum oxide, zinc borate, barium metaborate, red phosphorus, aluminum hydroxide, magnesium hydroxide, calcium aluminate, etc.); bromine flame retardants (tetrabromophthalic anhydride, hexabromobenzene, decabromobiphenyl ether, etc.); and phosphate ester flame retardants (tris(tribromophenyl)phosphate, etc.).

If a flame retardant is contained, the content of the flame retardant is preferably 0.5 to 40,000 parts by weight per 100 parts of acid generator, and more preferably 5 to 10,000 parts by weight.

As flame retardants, known flame retardants can be used, such as inorganic flame retardants (antimony trioxide, antimony pentoxide, tin oxide, tin hydroxide, molybdenum oxide, zinc borate, barium metaborate, red phosphorus, aluminum hydroxide, magnesium hydroxide, calcium aluminate, etc.); bromine flame retardants (tetrabromophthalic anhydride, hexabromobenzene, decabromobiphenyl ether, etc.); and phosphate ester flame retardants (tris(tribromophenyl)phosphate, etc.).

If a flame retardant is contained, the content of the flame retardant is preferably 0.5 to 40,000 parts by weight per 100 parts of acid generator, and more preferably 5 to 10,000 parts by weight.

As the defoaming agent, known defoaming agents can be used, such as alcohol defoaming agents, metal soap defoaming agents, phosphate ester defoaming agents, fatty acid ester defoaming agents, polyether defoaming agents, silicone defoaming agents, and mineral oil defoaming agents.

As the flow modifier, known flow modifiers can be used, and examples thereof include hydrogenated castor oil, oxidized polyethylene, organic bentonite, colloidal silica, amide wax, metal soap, and acrylic ester polymer.
As the light stabilizer, known light stabilizers can be used, and examples thereof include ultraviolet absorbing stabilizers (benzotriazole, benzophenone, salicylate, cyanoacrylate, derivatives thereof, etc.); radical scavenging stabilizers (hindered amines, etc.); and quenching stabilizers (nickel complexes, etc.).
As the antioxidant, known antioxidants can be used, and examples thereof include phenol-based antioxidants (monophenol-based, bisphenol-based, polymeric phenol-based, etc.), sulfur-based antioxidants, and phosphorus-based antioxidants.
As the adhesion promoter, known adhesion promoters can be used, and examples thereof include coupling agents, silane coupling agents, and titanium coupling agents.
As the ion scavenger, known ion scavenger agents can be used, and examples thereof include organic aluminum (alkoxy aluminum, phenoxy aluminum, etc.).
As the coloring inhibitor, known coloring inhibitors can be used, and generally, antioxidants are effective, and examples thereof include phenol-based antioxidants (monophenol-based, bisphenol-based, polymeric phenol-based, etc.), sulfur-based antioxidants, and phosphorus-based antioxidants, but they are almost ineffective in preventing coloring during heat resistance tests at high temperatures.

When an antifoaming agent, flow adjuster, light stabilizer, antioxidant, adhesion promoter, ion scavenger, or coloring inhibitor is contained, the content of each is preferably 0.1 to 20,000 parts by weight, more preferably 0.5 to 5,000 parts by weight, per 100 parts of acid generator.

There are no restrictions on the solvent as long as it can be used to dissolve the cationic polymerizable compound and adjust the viscosity of the active energy ray-curable composition, and those listed above as solvents for the acid generator can be used.

If a solvent is contained, the content of the solvent is preferably 50 to 2,000,000 parts by weight per 100 parts of acid generator, and more preferably 200 to 500,000 parts by weight.

Non-reactive resins include polyester, polyvinyl acetate, polyvinyl chloride, polybutadiene, polycarbonate, polystyrene, polyvinyl ether, polyvinyl butyral, polybutene, hydrogenated styrene-butadiene block copolymer, (meth)acrylic acid ester copolymer, and polyurethane. The number average molecular weight of these resins is preferably 1,000 to 500,000, and more preferably 5,000 to 100,000 (the number average molecular weight is a value measured by a common method such as GPC).

When a non-reactive resin is contained, the content of the non-reactive resin is preferably 5 to 400,000 parts by weight per 100 parts of acid generator, and more preferably 50 to 150,000 parts by weight.

When a non-reactive resin is contained, it is desirable to dissolve the non-reactive resin in a solvent in advance so that the non-reactive resin can be easily dissolved in the cationically polymerizable compound or the like.

Radically polymerizable compounds that can be used include known radically polymerizable compounds such as those described in "Photopolymer Handbook" edited by the Photopolymer Forum (1989, Industrial Research Institute), "UV/EB Curing Technology" edited by the General Technology Center (1982, General Technology Center), "UV/EB Curing Materials" edited by the RadTech Research Group (1992, CMC), and "Causes of Curing Failure and Inhibition in UV Curing and Countermeasures" edited by the Technical Information Association (2003, Technical Information Association), including monofunctional monomers, difunctional monomers, polyfunctional monomers, epoxy (meth)acrylates, polyester (meth)acrylates, and urethane (meth)acrylates.

When a radically polymerizable compound is contained, the content of the radically polymerizable compound is preferably 5 to 400,000 parts by weight per 100 parts of acid generator, and more preferably 50 to 150,000 parts by weight.

When containing radically polymerizable compounds, it is preferable to use a radical polymerization initiator that starts polymerization by heat or light in order to increase the molecular weight of these compounds through radical polymerization.

As the radical polymerization initiator, known radical polymerization initiators can be used, including thermal radical polymerization initiators (organic peroxides, azo compounds, etc.) and photoradical polymerization initiators (acetophenone-based initiators, benzophenone-based initiators, Michler's ketone-based initiators, benzoin-based initiators, thioxanthone-based initiators, acylphosphine-based initiators, etc.).

When a radical polymerization initiator is contained, the content of the radical polymerization initiator is preferably 0.01 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, per 100 parts of the radical polymerizable compound.

The active energy ray-curable composition of the present invention can be prepared by uniformly mixing and dissolving a cationically polymerizable compound, an acid generator, and, if necessary, additives at room temperature (approximately 20 to 30°C) or, if necessary, under heating (approximately 40 to 90°C), or by further kneading using a three-roll mill or the like.

The active energy ray-curable composition of the present invention can be cured by irradiation with active energy rays to give a cured product.
The active energy rays may be any rays as long as they have energy sufficient to induce decomposition of the acid generator of the present invention, but are preferably active energy rays in the ultraviolet to visible light region (wavelength: about 100 to about 800 nm) obtained from low-pressure, medium-pressure, high-pressure, or ultra-high-pressure mercury lamps, metal halide lamps, LED lamps, xenon lamps, carbon arc lamps, fluorescent lamps, semiconductor solid-state lasers, argon lasers, He—Cd lasers, KrF excimer lasers, ArF excimer lasers, F2 lasers, etc. High-energy radiation such as electron beams or X-rays can also be used as the active energy rays.

The irradiation time for active energy rays is affected by the intensity of the active energy rays and the permeability of the active energy ray-curable composition, but approximately 0.1 to 10 seconds at room temperature (approximately 20 to 30°C) is sufficient. However, if the permeability of the active energy ray is low or the film thickness of the active energy ray-curable composition is thick, it may be preferable to apply a longer time. Most active energy ray-curable compositions cure by cationic polymerization 0.1 seconds to several minutes after irradiation with active energy rays, but if necessary, they can be post-cured by heating at room temperature (approximately 20 to 30°C) to 200°C for several seconds to several hours after irradiation with active energy rays.

Specific applications of the active energy ray-curable composition of the present invention include paints, coating agents, various coating materials (hard coats, stain-resistant coatings, anti-fogging coatings, contact-resistant coatings, optical fibers, etc.), backside treatment agents for adhesive tapes, release coating materials for release sheets for adhesive labels (release paper, release plastic films, release metal foils, etc.), printing plates, dental materials (dental compounds, dental composites), inks, inkjet inks, positive resists (connection terminals and wiring pattern formation in the manufacture of electronic components such as circuit boards, CSPs, and MEMS elements), resist films, liquid resists, negative resists (permanent film materials such as surface protective films for semiconductor elements, interlayer insulating films, and planarizing films), MEMS resists, positive photosensitive resins, etc. Examples of applications of the present invention include photosensitive materials, negative photosensitive materials, various adhesives (temporary fixing agents for various electronic components, adhesives for HDDs, adhesives for pickup lenses, adhesives for functional films for FPDs (polarizing plates, anti-reflection films, etc.)), holographic resins, FPD materials (color filters, black matrices, partition materials, photospacers, ribs, alignment films for liquid crystals, sealants for FPDs, etc.), optical members, molding materials (for construction materials, optical components, lenses), casting materials, putty, glass fiber impregnation agents, fillers, sealing materials, encapsulants, optical semiconductor (LED) encapsulants, optical waveguide materials, nanoimprint materials, materials for stereolithography and microstereolithography, and the like. In particular, the resulting cured products have little coloring and excellent transparency, making them ideal for optical applications.

Since the photoacid generator of the present invention generates a strong acid upon exposure to light, it can also be used as a photoacid generator for known chemically amplified resist materials (see, for example, JP 2003-267968 A, JP 2003-261529 A, and JP 2002-193925 A).

Chemically amplified resist materials include: (1) two-component chemically amplified positive resists, the essential components of which are a resin that becomes soluble in alkaline developer under the action of acid and a photoacid generator; (2) three-component chemically amplified positive resists, the essential components of which are a resin that is soluble in alkaline developer, a dissolution inhibitor that becomes soluble in alkaline developer under the action of acid, and a photoacid generator; and (3) chemically amplified negative resists, the essential components of which are a resin that is soluble in alkaline developer, a crosslinker that crosslinks the resin when heated in the presence of acid, making it insoluble in alkaline developer, and a photoacid generator.

The chemically amplified positive photoresist composition of the present invention is characterized by containing component (A) containing the photoacid generator of the present invention, which is a compound that generates acid upon exposure to light, and resin component (B) whose solubility in alkali increases due to the action of acid.

In the chemically amplified positive photoresist composition of the present invention, component (A) may be used in combination with other conventionally known photoacid generators. Examples of other photoacid generators include onium salt compounds, sulfone compounds, sulfonate ester compounds, sulfonimide compounds, disulfonyldiazomethane compounds, disulfonylmethane compounds, oxime sulfonate compounds, hydrazine sulfonate compounds, triazine compounds, and nitrobenzyl compounds, as well as organic halides and disulfones.

Other conventionally known photoacid generators are preferably one or more of the group consisting of onium compounds, sulfonimide compounds, diazomethane compounds, and oxime sulfonate compounds.

When such other conventionally known photoacid generators are used in combination, the proportions used may be arbitrary, but typically the proportion of the other photoacid generators is 10 to 900 parts by weight, preferably 25 to 400 parts by weight, per 100 parts by weight of the total weight of the photoacid generators of the present invention.

The content of the above component (A) is preferably 0.05 to 5% by weight of the solids content of the chemically amplified positive photoresist composition.

<Resin Component (B) Having Increased Solubility in Alkali by the Action of Acid>
The "resin (B) whose solubility in alkali increases under the action of an acid" (referred to herein as "component (B)") used in the thick-film chemically amplified positive photoresist composition of the present invention is at least one resin selected from the group consisting of novolak resins (B1), polyhydroxystyrene resins (B2), and acrylic resins (B3), or a mixed resin or copolymer thereof.

[Novolac resin (B1)]
As the novolak resin (B1), a resin represented by the following general formula (b1) can be used.

In the above general formula (b1), R ^1b represents an acid dissociable, dissolution inhibiting group, R ^2b and R ^3b each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and n represents the number of repeating units of the structure in parentheses.

Furthermore, the acid dissociable, dissolution inhibiting group represented by R ^1b above is preferably a linear alkyl group having 1 to 6 carbon atoms, a branched alkyl group having 3 to 6 carbon atoms, a cyclic alkyl group having 3 to 6 carbon atoms, a tetrahydropyranyl group, a tetrahydrofuranyl group, or a trialkylsilyl group.

Specific examples of the acid dissociable, dissolution inhibiting group represented by R ^1b include a methoxyethyl group, an ethoxyethyl group, an n-propoxyethyl group, an isopropoxyethyl group, an n-butoxyethyl group, an isobutoxyethyl group, a tert-butoxyethyl group, a cyclohexyloxyethyl group, a methoxypropyl group, an ethoxypropyl group, a 1-methoxy-1-methylethyl group, a 1-ethoxy-1-methylethyl group, a tert-butoxycarbonyl group, a tert-butoxycarbonylmethyl group, a trimethylsilyl group, and a tri-tert-butyldimethylsilyl group.

[Polyhydroxystyrene resin (B2)]
As the polyhydroxystyrene resin (B2), a resin represented by the following general formula (b4) can be used.

In the above general formula (b4), R ^8b represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, R ^9b represents an acid dissociable, dissolution inhibiting group, and n represents the number of repeating units of the structure in parentheses.

The alkyl group having 1 to 6 carbon atoms is a linear alkyl group having 1 to 6 carbon atoms, a branched alkyl group having 3 to 6 carbon atoms, or a cyclic alkyl group having 3 to 6 carbon atoms, such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, or a neopentyl group. Examples of cyclic alkyl groups include a cyclopentyl group and a cyclohexyl group.

As the acid dissociable, dissolution inhibiting group represented by R ^9b , the same acid dissociable, dissolution inhibiting groups as those exemplified for R ^1b can be used.

Furthermore, polyhydroxystyrene resin (B2) may contain other polymerizable compounds as structural units in order to appropriately control the physical and chemical properties. Examples of such polymerizable compounds include known radically polymerizable compounds and anionically polymerizable compounds. Examples include monocarboxylic acids such as acrylic acid; dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; methacrylic acid derivatives having a carboxyl group and an ester bond, such as 2-methacryloyloxyethyl succinic acid; (meth)acrylic acid alkyl esters such as methyl (meth)acrylate; (meth)acrylic acid hydroxyalkyl esters such as 2-hydroxyethyl (meth)acrylate; dicarboxylic acid diesters such as diethyl maleate; vinyl group-containing aromatic compounds such as styrene and vinyltoluene; vinyl group-containing aliphatic compounds such as vinyl acetate; conjugated diolefins such as butadiene and isoprene; nitrile group-containing polymerizable compounds such as acrylonitrile; chlorine-containing polymerizable compounds such as vinyl chloride; and amide bond-containing polymerizable compounds such as acrylamide.

[Acrylic resin (B3)]
As the acrylic resin (B3), resins represented by the following general formulas (b5) to (b10) can be used.

In the above general formulae (b5) to (b7), R ^10b to R ^17b each independently represent a hydrogen atom, a linear alkyl group having 1 to 6 carbon atoms, a branched alkyl group having 3 to 6 carbon atoms, a fluorine atom, or a linear fluorinated alkyl group having 1 to 6 carbon atoms or a branched fluorinated alkyl group having 3 to 6 carbon atoms; X ^b forms a hydrocarbon ring having 5 to 20 carbon atoms together with the carbon atom to which it is bonded; Y ^b represents an aliphatic cyclic group or alkyl group which may have a substituent; n represents the number of repeating units of the structure in parentheses; p is an integer of 0 to 4; and q is 0 or 1.

In general formula (b8), general formula (b9), and general formula (b10), R ^18b , R ^20b , and R ^21b each independently represent a hydrogen atom or a methyl group; in general formula (b8), each R ^19b each independently represent a hydrogen atom, a hydroxyl group, a cyano group, or a COOR ^23b group (wherein R ^23b represents a hydrogen atom, a linear alkyl group having 1 to 4 carbon atoms, a branched alkyl group having 3 to 4 carbon atoms, or a cycloalkyl group having 3 to 20 carbon atoms); in general formula (b10), each R ^22b each independently represent a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, or a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms; and at least one of R ^22b is the alicyclic hydrocarbon group or a derivative thereof, or any two R ^22b are bonded to each other to form, together with the common carbon atom to which they are bonded, a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, and the remaining R ^22b represents a linear alkyl group having 1 to 4 carbon atoms or a branched alkyl group having 3 to 4 carbon atoms, or a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof.

Among the above components (B), it is preferable to use acrylic resin (B3).

The polystyrene-equivalent weight-average molecular weight of component (B) is preferably 10,000 to 600,000, more preferably 50,000 to 600,000, and even more preferably 230,000 to 550,000. By achieving such a weight-average molecular weight, the resist resin will have excellent physical properties.

Furthermore, component (B) is preferably a resin with a polydispersity of 1.05 or greater. Here, "polydispersity" refers to the weight-average molecular weight divided by the number-average molecular weight. Achieving this polydispersity results in excellent plating resistance and resin physical properties for the resist.

The content of the above component (B) is preferably 5 to 60% by weight of the solid content of the chemically amplified positive photoresist composition.

<Alkali-soluble resin (C)>
In order to improve the resin properties of the resist, the chemically amplified positive photoresist composition of the present invention preferably further contains an alkali-soluble resin (herein referred to as "component (C)"). Component (C) is preferably at least one resin selected from the group consisting of novolak resins, polyhydroxystyrene resins, acrylic resins, and polyvinyl resins.

The content of component (C) is preferably 5 to 95 parts by weight, and more preferably 10 to 90 parts by weight, per 100 parts by weight of component (B). A content of 5 parts by weight or more can improve the resin properties of the resist, while a content of 95 parts by weight or less tends to prevent film loss during development.

<Acid Diffusion Controller (D)>
The chemically amplified positive photoresist composition for thick films of the present invention preferably further contains an acid diffusion controller (D) (referred to herein as "component (D)") in order to improve the resist pattern shape, deposition stability, etc. Component (D) is preferably a nitrogen-containing compound, and may further contain an organic carboxylic acid or a phosphorus oxo acid or a derivative thereof, as necessary.

The chemically amplified positive photoresist composition of the present invention may further contain an adhesion promoter to improve adhesion to the substrate. The adhesion promoter used is preferably a functional silane coupling agent.

In addition, the chemically amplified positive photoresist composition of the present invention may further contain a surfactant to improve coating properties, defoaming properties, leveling properties, etc.

In addition, the chemically amplified positive photoresist composition of the present invention may further contain an acid, an acid anhydride, or a high-boiling point solvent to finely adjust the solubility in alkaline developers.

The chemically amplified positive photoresist composition of the present invention does not generally require a sensitizer, but can contain a sensitizer to enhance sensitivity, if necessary. Such sensitizers can be any of the conventionally known sensitizers, including those listed above.

The amount of these sensitizers used is 5 to 500 parts by weight, preferably 10 to 300 parts by weight, per 100 parts by weight of the total weight of the photoacid generator of the present invention.

The chemically amplified positive photoresist composition of the present invention can also contain an organic solvent to adjust viscosity. Specific examples of organic solvents include those listed above.

The amount of these organic solvents used is preferably in the range of 30% by weight or more solids concentration so that the film thickness of the photoresist layer obtained using the chemically amplified positive photoresist composition of the present invention (e.g., by spin coating) is 5 μm or more.

The thick-film chemically amplified positive photoresist composition of the present invention can be prepared, for example, by simply mixing and stirring the above-mentioned components using a conventional method. If necessary, the components may be dispersed and mixed using a dispersing machine such as a dissolver, homogenizer, or triple-roll mill. After mixing, the components may be further filtered using a mesh or membrane filter.

The chemically amplified positive photoresist composition of the present invention is suitable for forming a photoresist layer having a thickness of typically 5 to 150 μm, more preferably 10 to 120 μm, and even more preferably 10 to 100 μm, on a support. This photoresist laminate comprises a photoresist layer made of the chemically amplified positive photoresist composition of the present invention laminated on a support.

The substrate is not particularly limited and can be any conventional substrate, such as a substrate for electronic components or a substrate on which a predetermined wiring pattern is formed. Examples of such substrates include metal substrates such as silicon, silicon nitride, titanium, tantalum, palladium, titanium tungsten, copper, chromium, iron, and aluminum, as well as glass substrates. In particular, the chemically amplified positive photoresist composition of the present invention can successfully form a resist pattern even on copper substrates. Examples of materials that can be used for the wiring pattern include copper, solder, chromium, aluminum, nickel, and gold.

The photoresist laminate can be produced, for example, as follows. That is, a solution of the chemically amplified positive photoresist composition prepared as described above is applied to a substrate, and the solvent is removed by heating to form the desired coating film. Methods that can be used to apply the composition to the substrate include spin coating, slit coating, roll coating, screen printing, and applicator methods. Pre-baking conditions for the coating film of the composition of the present invention vary depending on the type and proportion of each component in the composition, the coating film thickness, etc., but are typically 70 to 150°C, preferably 80 to 140°C, for approximately 2 to 60 minutes.

The thickness of the photoresist layer is typically in the range of 5 to 150 μm, preferably 10 to 120 μm, and more preferably 10 to 100 μm.

To form a resist pattern using the photoresist laminate obtained in this manner, the obtained photoresist layer is selectively irradiated (exposed) to light or radiation, for example, ultraviolet light or visible light with a wavelength of 300 to 500 nm, through a mask with a predetermined pattern.

Here, "light" is synonymous with active energy rays and may be any light that activates a photoacid generator to generate an acid, including ultraviolet light, visible light, and far ultraviolet light. "Radiation" refers to X-rays, electron beams, ion beams, etc. Examples of light or radiation sources that can be used include low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, argon gas lasers, and LED lamps. The radiation dose varies depending on the type and amount of each component in the composition, the coating film thickness, and other factors, but is, for example, 50 to 10,000 mJ/ ^cm2 when an ultra-high-pressure mercury lamp is used.

After exposure, the photoresist layer is heated using a known method to promote the diffusion of the acid and change the alkaline solubility of the exposed areas. Then, for example, a specific alkaline aqueous solution is used as a developer to dissolve and remove the unwanted areas, yielding the desired resist pattern.

The development time varies depending on the type and ratio of each component of the composition and the dry film thickness of the composition, but is usually 1 to 30 minutes. The development method can be any of the following: puddle, dipping, puddle, or spray development. After development, the film is washed with running water for 30 to 90 seconds and then dried using an air gun or oven.

Connecting terminals such as metal posts and bumps can be formed by embedding a conductor such as metal, for example by plating, into the non-resist portions of the resist pattern thus obtained (portions removed with alkaline developer). There are no particular restrictions on the plating method, and various conventionally known methods can be used. Suitable plating solutions include solder plating, copper plating, gold plating, and nickel plating. Finally, the remaining resist pattern is removed using a stripper or similar solution according to standard procedures.

The chemically amplified positive photoresist composition of the present invention can also be used as a dry film. This dry film has a protective film formed on both sides of a layer of the chemically amplified positive photoresist composition of the present invention. The film thickness of the layer of the chemically amplified positive photoresist composition is typically in the range of 10 to 150 μm, preferably 20 to 120 μm, and more preferably 20 to 80 μm. The protective film is not particularly limited, and any resin film conventionally used in dry films can be used. For example, one film can be a polyethylene terephthalate film, and the other film can be one selected from the group consisting of polyethylene terephthalate film, polypropylene film, and polyethylene film.

The above-mentioned chemically amplified positive dry film can be produced, for example, as follows. That is, a solution of the chemically amplified positive photoresist composition prepared as described above is applied to one of the protective films, and the solvent is removed by heating to form the desired coating film. Drying conditions vary depending on the type and ratio of each component in the composition, the coating film thickness, etc., but typically require drying at 60 to 100°C for about 5 to 20 minutes.

To form a resist pattern using the chemically amplified dry film obtained in this manner, one protective film of the chemically amplified positive dry film is peeled off, and the exposed surface is laminated onto a support with the support facing the above-mentioned support to obtain a photoresist layer. After that, the resist is pre-baked to dry it, and then the other protective film is peeled off.

A resist pattern can be formed on the photoresist layer thus obtained on the support in the same manner as described above for the photoresist layer formed by applying it directly onto the support.

The chemically amplified negative photoresist composition of the present invention is characterized by containing component (E) containing the photoacid generator of the present invention, which is a compound that generates acid upon exposure to light or radiation, alkali-soluble resin (F) having a phenolic hydroxyl group, and crosslinker (G).

In the chemically amplified negative photoresist composition of the present invention, component (E) may be used in combination with other conventionally known photoacid generators. Examples of other photoacid generators include onium salt compounds, sulfone compounds, sulfonate ester compounds, sulfonimide compounds, disulfonyldiazomethane compounds, disulfonylmethane compounds, oxime sulfonate compounds, hydrazine sulfonate compounds, triazine compounds, and nitrobenzyl compounds, as well as organic halides and disulfones.

Other conventionally known photoacid generators are preferably one or more selected from the group consisting of onium compounds, sulfonimide compounds, diazomethane compounds, and oxime sulfonate compounds.

When such other conventionally known photoacid generators are used in combination, the proportions used may be arbitrary, but typically the proportion of the other photoacid generators is 10 to 900 parts by weight, preferably 25 to 400 parts by weight, per 100 parts by weight of the total weight of the photoacid generators of the present invention.

The content of the above component (E) is preferably 0.01 to 10% by weight of the solids content of the chemically amplified negative photoresist composition.

Alkali-soluble resin having a phenolic hydroxyl group (F)
Examples of the "alkali-soluble resin having a phenolic hydroxyl group" (hereinafter referred to as "phenolic resin (F)") used in the present invention include novolak resins, polyhydroxystyrenes, copolymers of polyhydroxystyrenes, copolymers of hydroxystyrene and styrene, copolymers of hydroxystyrene, styrene and a (meth)acrylic acid derivative, phenol-xylylene glycol condensation resins, cresol-xylylene glycol condensation resins, and phenol-dicyclopentadiene condensation resins. Among these, novolak resins, polyhydroxystyrenes, copolymers of polyhydroxystyrenes, copolymers of hydroxystyrene and styrene, copolymers of hydroxystyrene, styrene and a (meth)acrylic acid derivative, and phenol-xylylene glycol condensation resins are preferred. These phenolic resins (F) may be used alone or in combination of two or more.

The phenolic resin (F) may contain a low molecular weight phenolic compound as part of its components.
Examples of the phenolic low molecular weight compound include 4,4'-dihydroxydiphenylmethane and 4,4'-dihydroxydiphenyl ether.

Crosslinking agent (G)
The "crosslinking agent" (hereinafter also referred to as "crosslinking agent (G)") in the present invention is not particularly limited as long as it acts as a crosslinking component (curing component) that reacts with the phenolic resin (F). Examples of the crosslinking agent (G) include compounds having at least two alkyl-etherified amino groups in the molecule, compounds having at least two alkyl-etherified benzene groups in the molecule as a skeleton, oxirane ring-containing compounds, thiirane ring-containing compounds, oxetanyl group-containing compounds, and isocyanate group-containing compounds (including blocked compounds).

Among these crosslinking agents (G), compounds having at least two alkyl-etherified amino groups in the molecule and oxirane ring-containing compounds are preferred. Furthermore, it is even more preferred to use a compound having at least two alkyl-etherified amino groups in the molecule and an oxirane ring-containing compound in combination.

The amount of the crosslinking agent (G) in the present invention is preferably 1 to 100 parts by weight, more preferably 5 to 50 parts by weight, per 100 parts by weight of the phenolic resin (F). When the amount of the crosslinking agent (G) is 1 to 100 parts by weight, the curing reaction proceeds sufficiently, and the resulting cured product has a high resolution and a good pattern shape, and is excellent in heat resistance and electrical insulation, which is preferable.
Furthermore, when a compound having an alkyl-etherified amino group and an oxirane ring-containing compound are used in combination, the content of the oxirane ring-containing compound is preferably 50% by weight or less, more preferably 5 to 40% by weight, and particularly preferably 5 to 30% by weight, relative to 100% by weight of the total of the compound having an alkyl-etherified amino group and the oxirane ring-containing compound.
In this case, the resulting cured film is preferable because it has excellent chemical resistance without impairing high resolution.

Crosslinked fine particles (H)
The chemically amplified negative photoresist composition of the present invention may further contain crosslinked fine particles (hereinafter also referred to as "crosslinked fine particles (H)") in order to improve the durability and thermal shock resistance of the resulting cured product.

The average particle size of the crosslinked fine particles (H) is usually 30 to 500 nm, preferably 40 to 200 nm, and more preferably 50 to 120 nm.
The method for controlling the particle size of the crosslinked microparticles (H) is not particularly limited. For example, when the crosslinked microparticles are synthesized by emulsion polymerization, the particle size can be controlled by controlling the number of micelles during emulsion polymerization through the amount of emulsifier used.
The average particle size of the crosslinked fine particles (H) is a value measured by diluting a dispersion of the crosslinked fine particles in a conventional manner using a light scattering flow distribution measuring device or the like.

The amount of crosslinked fine particles (H) blended is preferably 0.5 to 50 parts by weight, and more preferably 1 to 30 parts by weight, per 100 parts by weight of the phenolic resin (F). When the amount of crosslinked fine particles (H) blended is 0.5 to 50 parts by weight, excellent compatibility or dispersibility with other components can be achieved, and the thermal shock resistance and heat resistance of the resulting cured film can be improved.

Adhesion Aid The chemically amplified negative photoresist composition of the present invention may contain an adhesion aid in order to improve adhesion to a substrate.
Examples of the adhesion aid include functional silane coupling agents having a reactive substituent such as a carboxyl group, a methacryloyl group, an isocyanate group, or an epoxy group.

The amount of adhesion aid blended is preferably 0.2 to 10 parts by weight, more preferably 0.5 to 8 parts by weight, per 100 parts by weight of the phenolic resin (F). A blending amount of this adhesion aid of 0.2 to 10 parts by weight is preferred because it provides excellent storage stability and good adhesion.

Solvent The chemically amplified negative photoresist composition of the present invention may contain a solvent in order to improve the handleability of the resin composition and to adjust the viscosity and storage stability.
The solvent is not particularly limited, but specific examples include those described above.

Other Additives The chemically amplified negative photoresist composition of the present invention may contain other additives as needed, provided that the additives do not impair the properties of the present invention. Examples of such additives include inorganic fillers, sensitizers, quenchers, leveling agents, surfactants, etc.

The method for preparing the chemically amplified negative photoresist composition of the present invention is not particularly limited, and it can be prepared by known methods. It can also be prepared by stirring a fully stoppered sample bottle containing each component on a wave rotor.

The cured product of the present invention is characterized by being obtained by curing the chemically amplified negative photoresist composition.
The chemically amplified negative photoresist composition according to the present invention has a high film retention rate and excellent resolution, and the cured product thereof has excellent electrical insulation properties, thermal shock resistance, etc., and therefore the cured product thereof can be suitably used as a surface protection film, a planarizing film, an interlayer insulating film material, etc. for electronic components such as semiconductor elements and semiconductor packages.

To form the cured product of the present invention, the aforementioned chemically amplified negative photoresist composition of the present invention is first applied to a support (such as a resin-coated copper foil, a copper-clad laminate, a silicon wafer or an alumina substrate with a metal sputtered film, etc.), and then dried to volatilize the solvent, forming a coating film. The resulting film is then exposed to light through a desired mask pattern and heat-treated (hereinafter, this heat treatment is referred to as "PEB") to promote the reaction between the phenolic resin (F) and the crosslinking agent (G). The resulting film is then developed with an alkaline developer to dissolve and remove the unexposed areas, yielding the desired pattern. A heat treatment is then performed to develop the insulating film properties, yielding a cured film.

The resin composition can be applied to a support by a coating method such as dipping, spraying, bar coating, roll coating, spin coating, etc. The thickness of the coating film can be appropriately controlled by adjusting the coating means and the solids concentration and viscosity of the composition solution.
Examples of radiation used for exposure include ultraviolet rays from low-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, g-line steppers, h-line steppers, i-line steppers, gh-line steppers, ghi-line steppers, etc., electron beams, laser beams, etc. The exposure dose is appropriately selected depending on the light source used, the resin film thickness, etc., but for example, in the case of ultraviolet irradiation from a high-pressure mercury lamp, the exposure dose is about 100 to 50,000 J/ ^m2 for a resin film thickness of 1 to 50 μm.

After exposure, the above-mentioned PEB treatment is carried out to promote the curing reaction of the phenolic resin (F) and crosslinking agent (G) due to the generated acid. PEB conditions vary depending on the amount of resin composition and the film thickness used, but are typically 70 to 150°C, preferably 80 to 120°C, for approximately 1 to 60 minutes. The film is then developed with an alkaline developer to dissolve and remove the unexposed areas, forming the desired pattern. Development methods in this case include shower development, spray development, immersion development, and paddle development. Development conditions are typically 20 to 40°C for approximately 1 to 10 minutes.

Furthermore, after development, the composition can be sufficiently cured by heat treatment to fully develop its insulating film properties. While there are no particular limitations on the curing conditions, the composition can be cured by heating at a temperature of 50-250°C for approximately 30 minutes to 10 hours, depending on the intended use of the cured product. Furthermore, to fully promote curing and prevent deformation of the resulting pattern, the composition can be heated in two stages. For example, in the first stage, the composition can be heated at a temperature of 50-120°C for approximately 5 minutes to 2 hours, and then further heated at a temperature of 80-250°C for approximately 10 minutes to 10 hours to achieve curing. Under these curing conditions, a typical oven, infrared furnace, or other heating equipment can be used.

The present invention will be explained in detail below using examples and comparative examples, but the present invention is not limited thereto.

Production Example 1 (Production of PAG-1)
36 g of potassium hexafluorophosphate, 100 mL of acetonitrile, 40 g of diphenyl sulfoxide, 60 g of acetic anhydride, and 30 g of concentrated sulfuric acid were charged and mixed uniformly. 36 g of diphenyl sulfide was added dropwise to the mixture, ensuring the temperature did not exceed 40°C. After stirring at 40°C for 1 hour, the mixture was cooled to room temperature, 200 mL of water was added, and the mixture was stirred for 10 minutes, resulting in the separation of an oily substance. 200 mL of ethyl acetate was added to dissolve the oily substance, and the organic layer was separated. This organic layer was washed with 90 mL of 20% caustic soda and then 100 mL of water three times. The acetonitrile and ethyl acetate were then distilled off under reduced pressure to obtain 90 g of a pale yellow solid (yield 94%).
Analysis by H-NMR, C-NMR, F-NMR, IR, IC, and HPLC (using a high performance liquid chromatograph L-7000 manufactured by Hitachi, Ltd., trade name; the same applies hereinafter) revealed that the obtained product contained 99.0% hexafluorophosphate salt having a cation (C-1) and 1.0% salt of an anion having a structure (Y-1) and a cation (C-1).

Production Example 2 (Production of PAG-2)
The same procedure as in Production Example 1 was repeated except that 43 g of potassium hexafluorophosphate was changed to 55 g of potassium hexafluoroantimonate, and 96 g of a white solid was obtained (yield 85%).
Analysis similar to that in Production Example 1 revealed that the product contained 99.1% hexafluoroantimony salt having the cation (C-1) and 0.9% salt of an anion having the structure (Y-1) and the cation (C-1).

Production Example 3 (Production of PAG-3)
The same procedure as in Production Example 1 was repeated except that 43 g of potassium hexafluorophosphate was changed to 160 g of lithium tetrakispentafluorophenylborate, and 121 g of a white solid was obtained (yield 85%).
As a result of analysis carried out in the same manner as in Production Example 1, it was found that the product contained 99.1% of tetrakispentafluorophenyl borate salt having the cation (C-1) and 0.9% of a salt having the anion structure (Y-1) and the cation (C-1).

Production Example 4 (Production of PAG-4)
43 g of potassium hexafluorophosphate, 100 mL of acetonitrile, 40 g of diphenyl sulfoxide, 60 g of acetic anhydride, and 23 g of concentrated sulfuric acid were charged and mixed uniformly. 36 g of diphenyl sulfide was added dropwise to the mixture, ensuring the temperature did not exceed 40°C. After stirring at 40°C for 1 hour, the mixture was cooled to room temperature, 200 mL of water was added, and the mixture was stirred for 10 minutes, resulting in the separation of an oily substance. 200 mL of ethyl acetate was added to dissolve the oily substance, and the organic layer was separated. This organic layer was washed with 90 mL of 20% caustic soda and then once with 100 mL of water. The acetonitrile and ethyl acetate were then distilled off under reduced pressure to yield a pale yellow solid. Washing with methanol yielded 90 g of a white solid (94% yield).
As a result of carrying out the same analysis as in Production Example 1, the obtained product was found to contain 99.6% of hexafluorophosphate having a cation (C-1) and 0.4% of sulfate having a cation (C-1).

Production Example 5 (Production of PAG-5)
43 g of potassium hexafluorophosphate, 100 ml of acetonitrile, 40 g of diphenyl sulfoxide, 60 g of acetic anhydride, and 20 g of methanesulfonic acid were charged and mixed uniformly. 36 g of diphenyl sulfide was added dropwise thereto, ensuring that the temperature did not exceed 40°C. After stirring at 40°C for 1 hour, the mixture was cooled to room temperature, and 200 mL of water was added and stirred for 10 minutes, resulting in the separation of an oily substance. 200 mL of ethyl acetate was added to dissolve the oily substance, and the organic layer was separated. This organic layer was washed once with 90 mL of 20% caustic soda and 100 mL of water, after which the acetonitrile and ethyl acetate were distilled off under reduced pressure to obtain a pale yellow solid. After washing with methanol, 88 g of a white solid (yield 92%) was obtained. Analysis similar to that in Production Example 1 revealed that the resulting product contained 99.7% hexafluorophosphate salt with the cation (C-1) and 0.3% methanesulfonate salt with the cation (C-1).

Production Example 6 (Production of PAG-6)
Except for changing 43 g of potassium hexafluorophosphate to 177 g of sodium tetrakispentafluorophenyl gallate, 130 g of a white solid was obtained (yield 63%) in the same manner as in Production Example 5. As a result of carrying out the same analysis as in Production Example 1, the obtained product was found to contain 99.8% of tetrakispentafluorophenyl gallate salt having a cation (C-1) and 0.2% of methanesulfonate salt having a cation (C-1).

Production Example 7 (Production of PAG-7)
Except for changing 43 g of potassium hexafluorophosphate to 101 g of potassium trispentafluoroethyl trifluorophosphate, 106 g of a white solid (yield 70%) was obtained in the same manner as in Production Example 5. As a result of carrying out the same analysis as in Production Example 1, the obtained product was found to contain 99.7% trispentafluoroethyl trifluorophosphate having a cation (C-1) and 0.3% methanesulfonate having a cation (C-1).

Production Example 8 (Production of PAG-8)
43 g of potassium hexafluorophosphate, 100 mL of acetonitrile, 55 g of 4-[(phenyl)sulfinyl]biphenyl, 60 g of acetic anhydride, and 20 g of methanesulfonic acid were charged and mixed uniformly. 51 g of 4-(phenylthio)biphenyl was added dropwise thereto, ensuring the temperature did not exceed 40°C. After stirring at 40°C for 1 hour, the mixture was cooled to room temperature, 200 mL of water was added, and the mixture was stirred for 10 minutes, resulting in the separation of an oily substance. 200 mL of ethyl acetate was added to dissolve the oily substance, and the organic layer was separated. This organic layer was washed once with 90 mL of 20% caustic soda and 100 mL of water. The acetonitrile and ethyl acetate were then distilled off under reduced pressure to obtain a pale yellow solid. After washing with methanol, 100 g of a white solid was obtained (yield: 94%).
As a result of carrying out the same analysis as in Production Example 1, the obtained product was found to contain 99.5% of the hexafluorophosphate salt having the cation (C-2) and 0.5% of the methanesulfonate salt having the cation (C-2).

Production Example 9 (Production of PAG-9)
55 g of potassium hexafluoroantimonate, 100 mL of acetonitrile, 55 g of 4-[(phenyl)sulfinyl]biphenyl, 60 g of acetic anhydride, and 23 g of concentrated sulfuric acid were charged and mixed uniformly. 51 g of 4-(phenylthio)biphenyl was added dropwise thereto, ensuring the temperature did not exceed 40°C. After stirring at 40°C for 1 hour, the mixture was cooled to room temperature, 200 mL of water was added, and the mixture was stirred for 10 minutes, resulting in the separation of an oily substance. 200 mL of ethyl acetate was added to dissolve the oily substance, and the organic layer was separated. This organic layer was washed once with 90 mL of 20% caustic soda and 200 mL of water. The acetonitrile and ethyl acetate were then distilled off under reduced pressure to obtain a pale yellow solid. After washing with methanol, 100 g of a white solid (83% yield) was obtained.
As a result of analysis similar to that in Production Example 1, the obtained product was found to contain 99.5% hexafluoroantimonate salt having the cation (C-2) and 0.5% salt of an anion having the structure (Y-2) and the cation (C-2).

Production Example 10 (Production of PAG-10)
Except for changing 55 g of potassium hexafluoroantimonate to 160 g of lithium tetrakispentafluorophenylborate, 145 g of a pale yellow solid was obtained (yield 76%) in the same manner as in Production Example 9. As a result of carrying out the same analysis as in Production Example 1, the obtained product was found to contain 99.6% of a tetrakispentafluorophenylborate salt in which the cation was (C-2) and 0.4% of a salt in which the cation was (C-2) and the anion had the structure (Y-2).

Production Example 11 (Production of PAG-11)
Except for changing 55 g of potassium hexafluoroantimonate to 177 g of lithium tetrakispentafluorophenyl gallate, 152 g of a pale yellow solid was obtained (yield 76%) in the same manner as in Production Example 9. As a result of carrying out the same analysis as in Production Example 1, the obtained product was found to contain 99.5% of a tetrakispentafluorophenyl gallate salt in which the cation was (C-2) and 0.5% of a salt in which the cation was (C-2) and the anion had the structure (Y-2).

Production Example 12 (Production of PAG-12)
Except for changing 55 g of potassium hexafluoroantimonate to 101 g of potassium trispentafluoroethyl trifluorophosphate, 105 g of a pale yellow solid (yield 69%) was obtained in the same manner as in Production Example 9. As a result of carrying out the same analysis as in Production Example 1, the obtained product was found to contain 99.6% trispentafluoroethyl trifluorophosphate having the cation (C-2) and 0.4% of a salt of an anion having the structure (Y-2) and the cation (C-2).

Production Example 13 (Production of PAG-13)
43 g of potassium hexafluorophosphate, 100 mL of acetonitrile, 55 g of 2-(phenylsulfinyl)thioxanthone, 60 g of acetic anhydride, and 46 g of concentrated sulfuric acid were charged and mixed uniformly. 51 g of 2-(phenylthio)thioxanthone was added dropwise. The temperature rose due to heat generation during the reaction, but the mixture was cooled so as not to exceed 40°C. After stirring at 40°C for 1 hour, the mixture was cooled to room temperature, 200 mL of water was added, and the mixture was stirred for 10 minutes, resulting in the separation of an oily substance. 200 mL of ethyl acetate was added to dissolve the oily substance, and the organic layer was separated. This organic layer was washed once with 90 mL of 20% caustic soda and 200 mL of water. The acetonitrile and ethyl acetate were then distilled off under reduced pressure to obtain a pale yellow solid. Washing with methanol yielded 132 g of a yellow solid (91% yield).
As a result of carrying out the same analysis as in Production Example 1, the obtained product was found to contain 99.6% of a hexafluorophosphate salt having a cation (C-3) and 0.4% of a salt of an anion having a structure of (Y-3) and a cation (C-3).

Production Example 14 (Production of PAG-14)
Except for changing 43 g of potassium hexafluorophosphate to 55 g of potassium hexafluoroantimonate, 126 g of a yellow solid was obtained (yield: 78%) in the same manner as in Production Example 13. As a result of carrying out the same analysis as in Production Example 1, the obtained product was found to contain 99.6% hexafluoroantimonate salt having the cation (C-3) and 0.4% salt of an anion having the structure (Y-3) and the cation (C-3).

Production Example 15 (Production of PAG-15)
151 g of a pale yellow solid (71% yield) was obtained in the same manner as in Production Example 4, except that 40 g of diphenyl sulfoxide was replaced with 47 g of 4,4'-difluorodiphenyl sulfoxide and 43 g of potassium hexafluorophosphate was replaced with 177 g of sodium tetrakispentafluorophenyl gallate. As a result of analysis similar to that in Production Example 1, the obtained product contained 99.5% of tetrakispentafluorophenyl gallate salt having a cation (C-4) and 0.5% of sulfate salt having a cation (C-4).

Production Example 16 (Production of PAG-16)
87 g of a pale yellow solid (73% yield) was obtained in the same manner as in Production Example 15, except that 177 g of sodium tetrakispentafluorophenyl gallate was changed to 55 g of potassium hexafluoroantimonate. As a result of carrying out the same analysis as in Production Example 1, the obtained product was found to contain 99.5% hexafluoroantimonate having a cation (C-4) and 0.5% sulfate having a cation (C-4).

Production Example 17 (Production of PAG-17)
Except for changing the amount of diphenyl sulfoxide (40 g) to 66 g of 2-phenylsulfenyl anthraquinone and the amount of diphenyl sulfide (36 g) to 61 g of 2-phenylthioanthraquinone in Production Example 1, 101 g of a yellow solid was obtained (yield: 70%) in the same manner as in Production Example 1. As a result of carrying out the same analysis as in Production Example 1, the obtained product was found to contain 98.8% hexafluorophosphate salt having a cation (C-5) and 1.2% salt of an anion having a structure (Y-5) and a cation (C-5).

Production Example 18 (Production of PAG-18)
Except for changing the amount of diphenyl sulfoxide (40 g) to 67 g of 2-phenylsulfenylthianthrene and the amount of diphenyl sulfide (36 g) to 62 g of 2-phenylthiothianthrene in Production Example 1, 47 g of a yellow solid was obtained (yield 32%) in the same manner as in Production Example 1. As a result of carrying out the same analysis as in Production Example 1, the obtained product was found to contain 98.4% of a hexafluorophosphate salt having a cation (C-6) and 1.6% of a salt of an anion having a structure (Y-6) and a cation (C-6).

Comparative Production Examples 1 to 6 (Production of PAG-H1 to H6)
(Production of PAG-H1)
The pale yellow solid obtained in Production Example 1 was repeatedly recrystallized from dichloromethane/methanol to obtain a white solid. As a result of carrying out the same analysis as in Production Example 1, it was confirmed that the obtained product contained substantially 100% of a hexafluorophosphate salt of a cation having the structure (C-1).
(Production of PAG-H2 to H6)
As with PAG-H1, PAG-H2 to PAG-H6 were purified by recrystallization of the solids obtained in Production Examples 8, 13, 16, 17, and 18, respectively. The compositions are as shown in Table 2.

Comparative Production Examples 7 to 15 (Production of PAG-H7 to H15)
(Production of PAG-H7)
The crystallization filtrate obtained by the recrystallization procedure in Comparative Production Example 1 was collected and concentrated, and the resulting oil was washed with methanol and hexane to obtain a pale yellow solid. Analysis similar to that in Production Example 1 revealed that the resulting solid contained 95.2% of the hexafluorophosphate salt of a cation having the structure (C-1) and 4.8% of the salt of the anion having the structure (Y-1).
(Production of PAG-H8 to H15)
Similarly, the same procedure was carried out for PAG-H8 to H15 using the solids obtained in Production Examples 4, 5, 8, 9, 13, 16, 17, and 18, respectively, to give pale yellow to yellow solids. The compositions of the obtained solids are shown in Table 2.

Production Examples 19 to 27 (Production of PAG-19 to 27)
Appropriate amounts of PAG-H7 to PAG-H15 obtained in Comparative Production Examples 7 to 15 were mixed with PAG-1, 4, 5, 8, 9, 13, 16, 17, and 18 to obtain solid photoacid generators PAG-19 to 27. The compositions of the obtained solids are shown in Table 1.

<Preparation and Evaluation of Photocurable Composition>
The above photoacid generator was dissolved in propylene carbonate (solvent-1) in advance to a concentration of 50% by weight, and then uniformly mixed with an epoxy resin (described below), a cationically polymerizable compound, in the amounts shown in Tables 3 and 4 to prepare photocurable compositions (Examples 1 to 51 and Comparative Examples 1 to 27). The compositions were placed in light-shielding bottles and stored at the specified temperature for the specified period (storage conditions described below), and their storage stability and photo (UV) curability (cationic polymerization performance) were evaluated using the following methods. The results are shown in Tables 3 and 4.
<Epoxy resin>
EP-1: 2,2-bis(4-glycidyloxyphenyl)propane EP-2: 3',4'-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate EP-3: 3-ethyl-3-{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane

<Storage conditions>
Storage conditions: 40°C x 3 months <Storage stability>
A portion of the composition was taken out of the light-shielding bottle and evaluated for changes in viscosity and the presence or absence of precipitation.
(Evaluation criteria)
Good: The change in viscosity of the composition before and after storage was less than 1.5 times.
×: The viscosity of the composition changed by 1.5 times or more before and after storage.
<Photocuring (cationic polymerization performance) evaluation>
The composition obtained above was applied to a polyethylene terephthalate (PET) film with an applicator to a film thickness of 25 μm. The coated PET film was irradiated with light of a wavelength limited by a filter using an ultraviolet irradiation device. The filter used was an IRCF02 filter (manufactured by iGraphics Co., Ltd., a filter that cuts light of less than 340 nm). The hardness of the coating film 40 minutes after irradiation was measured using pencil hardness (JIS K5600-5-4:1999), and the results evaluated according to the following criteria are shown in Tables 3 and 4. A higher pencil hardness indicates better sensitivity (cationic polymerization curability) of the photocurable composition.

(Evaluation criteria)
◎: Pencil hardness is 2H or more ○: Pencil hardness is H to B
△: Pencil hardness is 2B to 4B
×: Liquid to tacky, pencil hardness cannot be measured

(Light irradiation conditions)
- Ultraviolet irradiation device: Belt conveyor type UV irradiation device (manufactured by iGraphics Co., Ltd.)
Lamp: 1.5kW high-pressure mercury lamp Filter: IRCF02 filter (manufactured by iGraphics Co., Ltd.)
Illuminance (measured with a 365 nm head illuminometer): 150 mW/cm ²
Accumulated light intensity (measured with a 365 nm head illuminometer): 200 mJ/cm ²

As shown in Tables 3 and 4, Examples 1 to 51 and Comparative Examples 1 to 27 demonstrate that compositions containing the photoacid generators of the present invention exhibit excellent UV curability and a good balance of storage stability. Comparative Examples 1 to 6 demonstrate that extremely high-purity photoacid generators exhibit excellent UV curability but poor storage stability. Using a photoacid generator containing a small amount of anion Y, as in the examples, improves storage stability. Furthermore, comparing Examples 20 to 27 and Comparative Examples 7 to 15 reveals that a molar ratio of anion Y of 2 mol% or less is preferable, since a high content of anion Y affects UV curability. Furthermore, Examples 28 to 51 and Comparative Examples 16 to 27 demonstrate that this tendency is independent of the type of cationically polymerizable epoxy resin used.

<Evaluation of Positive Photoresist Compositions>
(Preparation of evaluation samples)
One part of a photoacid generator, 40 parts of a resin represented by the following chemical formula (Resin-1) as resin component (B), and 60 parts of a novolak resin obtained by addition condensation of m-cresol and p-cresol in the presence of formaldehyde and an acid catalyst as resin component (C) were uniformly dissolved in 150 parts of 2-methoxy-1-methylethyl acetate (solvent-2), and the solution was filtered through a membrane filter with a pore size of 1 μm to prepare positive photoresist compositions with a solids concentration of 40 wt % (Examples 52 to 78). Positive photoresist compositions (Comparative Examples 28 to 42) were also prepared for the comparative examples in the same manner as in the above examples.
These compositions were stored at a predetermined temperature for a predetermined period of time, and the positive photoresist compositions were evaluated by the following method and compared with those immediately after blending. The results are shown in Table 5.

<Storage conditions>
Storage conditions: 20°C x 3 months

<Sensitivity evaluation>
The positive resist composition was spin-coated onto a silicon wafer substrate and then dried to obtain a photoresist layer having a film thickness of approximately 20 μm. This resist layer was pre-baked on a hot plate at 130°C for 6 minutes. After pre-baking, a pattern exposure (i-line) was performed using a TME-150RSC (manufactured by Topcon Corporation), followed by post-exposure baking (PEB) on a hot plate at 75°C for 5 minutes. The resist layer was then developed for 5 minutes by immersion using a 2.38 wt% aqueous solution of tetramethylammonium hydroxide, rinsed with running water, and blown with nitrogen to obtain a 10 μm line and space (L&S) pattern. Furthermore, the minimum exposure dose below which no residue of this pattern was observed, i.e., the minimum required exposure dose (corresponding to sensitivity) required to form a resist pattern, was measured.

<Pattern shape evaluation>
The dimension La of the lower side and the dimension Lb of the upper side of the cross section of the 10 μm L&S pattern formed on the silicon wafer substrate by the above operation were measured using a scanning electron microscope, and the pattern shape was evaluated according to the following criteria.
○: 0.85≦Lb/La≦1
×: Lb/La<0.85

As shown in Table 5, Examples 52-78 and Comparative Examples 28-42 demonstrate that chemically amplified positive photoresist compositions containing the photoacid generators of the present invention exhibit excellent resist sensitivity and excellent storage stability. Comparative Examples 28-33 demonstrate that although very high-purity photoacid generators provide excellent resist sensitivity, they also affect storage stability. It can be seen that using a photoacid generator containing a small amount of anion Y, as in the examples, improves storage stability. Furthermore, a comparison of Examples 70-78 and Comparative Examples 34-42 demonstrates that a molar ratio of anion Y of 2 mol % or less is preferable, since too high a content affects resist sensitivity and pattern shape.

<Preparation and Evaluation of Negative Photoresist Composition>
(Preparation of evaluation samples)
1 part of a photoacid generator, 100 parts of a copolymer (Mw=10,000) consisting of p-hydroxystyrene/styrene=80/20 (molar ratio) as component (F) which is a phenolic resin, 20 parts of hexamethoxymethylmelamine (manufactured by Sanwa Chemical Co., Ltd., trade name "Nikarak MW-390") as component (G) which is a crosslinking agent, and 1 part of butadiene/acrylonitrile/hydroxybutyl methacrylate/ Negative photoresist compositions of the present invention (Examples 79 to 105, Comparative Examples 43 to 57) were prepared by uniformly dissolving 10 parts of a copolymer (average particle size: 65 nm, Tg: -38°C) consisting of methacrylic acid/divinylbenzene = 64/20/8/6/2 (wt %), and 5 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Chisso Corporation, trade name "S510") as an adhesion aid component (J) in 145 parts of ethyl lactate (solvent-2).
These compositions were stored at a predetermined temperature for a predetermined period of time, and the negative photoresist compositions were evaluated by the following method and compared with those immediately after blending. The results are shown in Table 6.

<Storage conditions>
Storage conditions: 20°C x 3 months <Sensitivity evaluation>
Each composition was spin-coated onto a silicon wafer substrate and then heated and dried at 110°C for 3 minutes using a hot plate to obtain a resin coating film having a film thickness of approximately 20 μm. Subsequently, pattern exposure (i-line) was performed using a TME-150RSC (manufactured by Topcon Corporation), followed by post-exposure baking (PEB) for 3 minutes at 110°C using a hot plate. Subsequently, development was performed for 2 minutes by immersion using a 2.38 wt% aqueous solution of tetramethylammonium hydroxide, followed by rinsing with running water and blowing with nitrogen to obtain a 10 μm line-and-space pattern. Furthermore, the minimum required exposure dose (corresponding to sensitivity) required to form a pattern with a residual film ratio of 95% or more, which indicates the ratio of the residual film before and after development, was measured.

<Pattern shape evaluation>
The dimension La of the lower side and the dimension Lb of the upper side of the cross section of the 20 μm L&S pattern formed on the silicon wafer substrate by the above operation were measured using a scanning electron microscope, and the pattern shape was evaluated according to the following criteria.
○: 0.85≦Lb/La≦1
×: Lb/La<0.85

As shown in Table 6, Examples 79-105 and Comparative Examples 43-57 demonstrate that chemically amplified negative photoresist compositions containing the photoacid generators of the present invention exhibit excellent resist sensitivity and excellent storage stability. Comparative Examples 43-48 demonstrate that although a very high-purity photoacid generator provides excellent resist sensitivity, it also affects storage stability. It can also be seen that using a photoacid generator containing a small amount of anion Y, as in the examples, improves storage stability. Furthermore, a comparison of Examples 97-105 and Comparative Examples 49-57 demonstrates that a molar ratio of anion Y of 2 mol% or less is preferable, since too high a content affects resist sensitivity and pattern shape.

Activin energy ray-curable compositions using the activation energy ray-sensitive acid generator of the present invention are useful in paints, coating agents, various coating materials (hard coats, stain-resistant coatings, anti-fogging coatings, contact-resistant coatings, optical fibers, etc.), backside treatment agents for adhesive tapes, release coating materials for release sheets for adhesive labels (release paper, release plastic film, release metal foil, etc.), printing plates, dental materials (dental compounds, dental composites), inks, inkjet inks, resist films, liquid resists, negative resists (permanent film materials such as surface protective films for semiconductor elements, interlayer insulating films, planarizing films, etc.), resists for MEMS, negative resists, etc. The present invention is suitable for use in mold photosensitive materials, various adhesives (temporary fixing agents for various electronic components, adhesives for HDDs, adhesives for pickup lenses, adhesives for functional films for FPDs (deflectors, anti-reflection films, etc.)), holographic resins, FPD materials (color filters, black matrices, partition materials, photospacers, ribs, alignment films for liquid crystals, sealants for FPDs, etc.), optical members, molding materials (for construction materials, optical components, lenses), casting materials, putty, glass fiber impregnation agents, fillers, sealing materials, encapsulants, optical semiconductor (LED) encapsulants, optical waveguide materials, nanoimprint materials, materials for stereolithography, and materials for micro stereolithography.

Claims (10)

An actinic ray-sensitive acid generator comprising a sulfonium salt (A) represented by the following general formula (1) and a sulfonium salt (B) represented by the following general formula (2), wherein the content of the sulfonium salt (B) is 0.01 to 2 mol % relative to the total number of moles of the sulfonium salt (A) and the sulfonium salt (B):
[In formula (1), R ¹ to R ⁴ are organic groups bonded to a benzene ring; the number of R ² is 0 to 4, the numbers of R ¹ , R ³ , and R ⁴ are 0 to 5, and when R 2 is 0, a hydrogen atom is bonded; when a plurality of R ¹ to R ⁴ are bonded, they may be the same or different; and R ¹ to R ⁴ may form a ring structure either directly or via —O—, —S—, —SO—, —SO ₂ —, —NH—, —CO—, —COO—, —CONH—, an alkylene group, or a phenylene group; and X ⁻ is a monovalent anion having an element of Group 13 or 15 of the periodic table and having a halogen atom]
[In formula (2), R ¹ to R ⁴ are organic groups bonded to a benzene ring, the number of R ² is 0 to 4, the numbers of R ¹ , R ³ , and R ⁴ are 0 to 5, and when R 2 is 0, a hydrogen atom is bonded, and when a plurality of R ¹ to R ⁴ are bonded, they may be the same or different, and R ¹ to R ⁴ may form a ring structure either directly or via -O-, -S-, -SO-, -SO ₂ -, -NH-, -CO-, -COO-, -CONH-, an alkylene group, or a phenylene group, and Y ^- is a monovalent anion selected from the group consisting of HSO ₄ ^- and anions represented by the following general formula (3) ]
[In formula (3), R ⁵ and R ⁶ are hydrogen atoms or organic groups, the number of R 5 and R ⁶ is 0 to 5, and when R ⁵ and R ⁶ are 0, a hydrogen atom is bonded, and when a plurality of R ⁵ and R 6 are bonded, they may be the same or different, and R ⁵ and R ⁶ may form a ring structure with each other directly or via -O-, -S-, -SO-, -SO ₂ -, -NH-, -CO-, -COO-, -CONH-, an alkylene group or a phenylene group, and m and n are each 0 or 1, and m+n=1.] X ⁻ is SbF ₆ ⁻ , PF ₆ ⁻ , BF ₄ ⁻ , (CF ₃ CF ₂ ) ₃ PF ₃ ⁻ , ((CF ₃ ) ₂ CF) ₃ PF ₃ ⁻ , (CF ₃ CF ₂ CF ₂ ) ₃ PF ₃ ⁻ , (C ₆ F ₅ ) ₄ B ⁻ , ((CF ₃ ) ₂ C ₆ H ₃ ) ₄ B ⁻ , (C ₆ F ₅ ) ₄ Ga ⁻ , ((CF ₃ ) ₂ C ₆ H ₃ ) ₄ Ga ⁻ , trifluoromethanesulfonate anion, nonafluorobutanesulfonate anion, (CF ₃ SO ₂ ) ₃ C ⁻ , and (CF ₃ 2. The active energy ray-sensitive acid generator according to claim 1, wherein the acid generator is selected from the group consisting of anions represented by the formula SO ₂ ) ₂ N ^— . 3. An active energy ray-curable composition comprising the active energy ray-sensitive acid generator according to claim 1 or 2 and a cationically polymerizable compound. A cured product obtained by curing the active energy ray-curable composition according to claim 3 . A chemically amplified positive photoresist composition comprising: a component (A) containing the actinic ray-sensitive acid generator according to any one of claims 1 to 4 ; and a component (B) which is a resin whose solubility in alkali increases under the action of an acid. 6. The chemically amplified positive photoresist composition according to claim 5 , wherein the component (B) comprises at least one resin selected from the group consisting of a novolak resin (B1), a polyhydroxystyrene resin (B2), and an acrylic resin (B3). 7. The chemically amplified positive photoresist composition according to claim 5 , further comprising an alkali-soluble resin (C) and an acid diffusion controller (D). 3. A chemically amplified negative photoresist composition comprising: a component (E) containing the actinic ray-sensitive acid generator according to claim 1; a component (F) which is an alkali-soluble resin having a phenolic hydroxyl group; and a crosslinker component (G). 9. The chemically amplified negative photoresist composition according to claim 8 , further comprising a crosslinked fine particle component (H). A cured product obtained by curing the chemically amplified negative photoresist composition according to claim 8 or 9 .