Photoacid generator

Abstract

The present invention provides a useful photoacid generator which is contained in a photocurable composition, a chemically amplified positive photoresist composition and a chemically amplified negative photoresist composition, and which is useful for long-term storage stability of these compositions, especially for the achievement of a composition that has excellent long-term storage stability at low temperatures. The present invention is a photoacid generator which contains sulfonium salts represented by general formulae (1) to (3), and which is characterized in that the total area ratio of (2) and (3) is from 0.02 to 5.5 if the total area of (1) to (3) is taken as 100 when the contents of the sulfonium salts are determined by high-speed liquid chromatography (HPLC).

Description

Technical Field

[0001] The present invention relates to a photoacid generator useful as a photocurable composition, a chemically amplified positive photoresist composition, and a chemically amplified negative photoresist composition, and a photoacid generator useful for the long-term storage stability of these compositions.

Background Art

[0002] Onium salts such as sulfonium salts are known as photo cationic polymerization initiators for curing cationic polymerizable compounds such as epoxy compounds by irradiation with active energy rays such as light and electron beams (hereinafter referred to as light), or as photoacid generators because they generate acids upon light irradiation, and are widely used in photoresists, photosensitive materials, etc. (Patent Documents 1 to 6).

[0003] Incidentally, known methods are available for producing the photoacid generators described in these specifications, particularly sulfonium salts (Patent Documents 1 and 3). However, the sulfonium salts produced by such methods generate bissulfonium salts having two sulfonio groups in one molecule in addition to monosulfonium salts having one sulfonio group in one molecule. Generally, although bissulfonium salts have higher photoinitiation ability than monosulfonium salts, they have low solubility in cationic polymerizable monomers and dilution solvents used as necessary. Therefore, after adding and dissolving the sulfonium salts at the required concentration in these, there may be a problem that bissulfonium salts precipitate and settle over time from the sulfonium salt solution. In addition, cationic polymerizable compounds containing bissulfonium salts tend to thicken over time and have a problem that they cannot be stored for a long time. Therefore, the applicant of the present application has disclosed a production method capable of efficiently obtaining high-purity monosulfonium salts in order to solve the above problems (Patent Document 7). However, there are still problems with long-term storage stability for photocurable compositions and photoresist compositions that are becoming more sensitive. From the perspective of industrial use, it is disadvantageous to blend the above photoacid generator immediately before each use. For example, in the case of a composition that requires low-temperature storage, there has been a further need for improvement in the solubility of the photoacid generator at low temperatures and in the aggregation and precipitation during low-temperature storage.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above background, an object of the present invention is to provide a useful photoacid generator for use in a photocurable composition, a chemically amplified positive photoresist composition, and a chemically amplified negative photoresist composition, which is excellent in the long-term storage stability of these compositions, particularly in the long-term storage stability at low temperatures.

Means for Solving the Problems

[0006] The present inventor has found a photoacid generator suitable for the above object. That is, the present invention contains a sulfonium salt represented by general formulas (1) to (3), and when the content of the sulfonium salt is measured by high performance liquid chromatography (HPLC), the total area ratio of (2) and (3) when the total area of (1) to (3) is set to 100 is 0.02 or more and 5.5 or less. It is a photoacid generator characterized by the above.

[0007]

Chemical Formula

[0008] [In formulas (1) to (3), R 1 ~R 4 are organic groups bonded to the benzene ring, m, n, p, q each represent the number of R 1 ~R 4 , n is an integer from 0 to 4, m, p, q are integers from 0 to 5, in the case of 0, a hydrogen atom is bonded, and when m, n, p, q are 2 or more, they may be the same as or different from each other, and R 1 ~R 4may form a ring structure directly with each other or via -O-, -S-, -SO-, -SO2-, -NH-, -CO-, -COO-, -CONH-, an alkylene group or a phenylene group, and X is an atom (group) that can become a monovalent anion.

[0009] The present invention also relates to a photocurable composition characterized by containing the above photoacid generator and a cationic polymerizable compound; a cured body characterized by being obtained by curing the above photocurable composition; a chemically amplified positive photoresist composition characterized by containing the above photoacid generator and a component (B) which is a resin whose solubility in alkali increases by the action of an acid; a chemically amplified negative photoresist composition characterized by containing the above photoacid generator, a component (F) which is an alkali-soluble resin having a phenolic hydroxyl group, and a crosslinking agent component (G); and a cured body characterized by being obtained by curing the above chemically amplified negative photoresist composition.

Advantages of the Invention

[0010] The photoacid generator of the present invention has high activity with respect to light, has cationic polymerization performance and crosslinking reaction performance, and further, a photosensitive composition using the photoacid generator of the present invention has long-term storage stability, particularly even when stored at low temperature, no aggregation or precipitation of the photoacid generator occurs, and a stable composition without performance deterioration due to storage can be obtained.

Modes for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described in detail.

[0012] R in formulas (1) to (3) 1 ~R 4 represents an organic group bonded to the benzene ring, and they may be the same or different. R 1 ~R 4Examples of the organic group include aryl groups having 6 to 30 carbon atoms, heteroaryl 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, hydroxy groups, alkoxy groups having 1 to 18 carbon atoms, aryloxy groups having 6 to 10 carbon atoms, alkylcarbonyl groups having 2 to 19 carbon atoms, arylcarbonyl groups having 7 to 11 carbon atoms, alkoxycarbonyl groups having 2 to 19 carbon atoms, aryloxycarbonyl groups having 7 to 11 carbon atoms, arylthiocarbonyl groups having 7 to 11 carbon atoms, acyloxy groups having 2 to 19 carbon atoms, arylthio groups having 6 to 20 carbon atoms, alkylthio groups having 1 to 18 carbon atoms, alkylsulfinyl groups having 1 to 18 carbon atoms, arylsulfinyl groups having 6 to 10 carbon atoms, alkylsulfonyl groups having 1 to 18 carbon atoms, arylsulfonyl groups having 6 to 10 carbon atoms, alkyleneoxy groups, amino groups, cyano groups, nitro groups and halogen groups.

[0013] In the above, examples of the aryl group having 6 to 30 carbon atoms include monocyclic aryl groups such as phenyl group and biphenylyl group, and condensed polycyclic aryl groups such as naphthyl, anthracenyl, phenanthrenyl, pyrenyl, chrysenyl, naphthacenyl, benzanthracenyl, anthraquinolyl, fluorenyl, naphthoquinone, anthraquinone.

[0014] Examples of the heteroaryl group having 4 to 30 carbon atoms include cyclic ones containing 1 to 3 heteroatoms such as oxygen, nitrogen, sulfur, etc., and these may be the same or different. Specific examples include monocyclic heteroaryl groups such as thienyl, furanyl, pyranyl, pyrrolyl, oxazolyl, thiazolyl, pyridyl, pyrimidyl, pyrazinyl, and condensed polycyclic heteroaryl groups such as indolyl, benzofuranyl, isobenzofuranyl, benzothienyl, isobenzothienyl, quinolinyl, isoquinolinyl, quinoxalinyl, quinazolinyl, carbazolyl, acridinyl, phenothiazinyl, phenazinyl, xanthenyl, thianthrenyl, phenoxazinyl, phenoxathiinyl, chromanyl, isochromanyl, dibenzothienyl, xanthonyl, thioxanthonyl, dibenzofuranyl.

[0015] Examples of alkyl groups having 1 to 30 carbon atoms include linear alkyl groups such as methyl, ethyl, propyl, butyl, hexadecyl, octadecyl, etc., branched alkyl groups such as isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, neopentyl, tert-pentyl, isohexyl, etc., and cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc.

[0016] Examples of alkenyl groups having 2 to 30 carbon atoms include vinyl, allyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-methyl-1-propenyl, etc.

[0017] Examples of alkynyl groups having 2 to 30 carbon atoms include ethynyl, 1-propynyl, 2-propynyl, 1-butynyl, 2-butynyl, 3-butynyl, 1-methyl-1-propynyl, 1-methyl-2-propynyl, etc.

[0018] Examples of alkoxy groups having 1 to 18 carbon atoms include methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, dodecyloxy, etc.

[0019] Examples of aryloxy groups having 6 to 10 carbon atoms include phenoxy, naphthyloxy, etc.

[0020] Examples of alkylcarbonyl groups having 2 to 19 carbon atoms include acetyl, trifluoroacetyl, propionyl, butanoyl, 2-methylpropionyl, heptanoyl, 2-methylbutanoyl, 3-methylbutanoyl, octanoyl, etc.

[0021] Examples of arylcarbonyl groups having 7 to 11 carbon atoms include benzoyl, 4-tert-butylbenzoyl, naphthoyl, etc.

[0022] Examples of the alkoxycarbonyl group having 2 to 19 carbon atoms include methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, isobutoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, and the like.

[0023] Examples of the aryloxycarbonyl group having 7 to 11 carbon atoms include phenoxycarbonyl, naphthoxycarbonyl, and the like.

[0024] Examples of the arylthiocarbonyl group having 7 to 11 carbon atoms include phenylthiocarbonyl, naphthoxythiocarbonyl, and the like.

[0025] Examples of the acyloxy group having 2 to 19 carbon atoms include acetoxy, ethylcarbonyloxy, propylcarbonyloxy, isobutylcarbonyloxy, sec-butylcarbonyloxy, tert-butylcarbonyloxy, octadecylcarbonyloxy, and the like.

[0026] Examples of the arylthio group having 6 to 20 carbon atoms include 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 the like.

[0027] Examples of the alkylthio group having 1 to 18 carbon atoms include methylthio, ethylthio, propylthio, tert-butylthio, neopentylthio, dodecylthio, and the like.

[0028] Examples of the alkylsulfinyl group having 1 to 18 carbon atoms include methylsulfinyl, ethylsulfinyl, propylsulfinyl, tert-pentylsulfinyl, octylsulfinyl and the like.

[0029] Examples of the arylsulfinyl group having 6 to 10 carbon atoms include phenylsulfinyl, tolylsulfinyl, naphthylsulfinyl and the like.

[0030] Examples of the alkylsulfonyl group having 1 to 18 carbon atoms include methylsulfonyl, ethylsulfonyl, propylsulfonyl, isopropylsulfonyl, butylsulfonyl, octylsulfonyl and the like.

[0031] Examples of the arylsulfonyl group having 6 to 10 carbon atoms include phenylsulfonyl, tolylsulfonyl, naphthylsulfonyl and the like.

[0032] Examples of the halogen group include fluoro, chloro, bromo and iodo.

[0033] Among these organic groups, preferably an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, an arylcarbonyl group having 7 to 11 carbon atoms, an alkylthio group having 1 to 6 carbon atoms, an arylthio group having 6 to 14 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, a chloro group, and a fluoro group; more preferably an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms, a heteroaryl group having 4 to 14 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylcarbonyl group having 2 to 6 carbon atoms, a benzoyl group, an aryloxy group having 6 to 10 carbon atoms, and a fluoro group.

[0034] In formulas (1) to (3), m, n, p, and q each represent the number of R 1 ~R 4 and n is an integer of 0 to 4, and m, p, and q are integers of 0 to 5. When it is 0, a hydrogen atom is bonded. When m, n, p, and q are 2 or more, they may be the same as or different from each other, and also R1 ~R 4 may form a ring structure directly with each other or via -O-, -S-, -SO-, -SO2-, -NH-, -CO-, -COO-, -CONH-, an alkylene group or a phenylene group. It is preferable that n is 0 to 2, and m, p, and q are 0 to 3, and more preferably 0 or 1 respectively. When m, n, p, and q are within these preferable ranges, the photoresponsiveness and solubility of the sulfonium salt are improved.

[0035] Among the sulfonium salts represented by formula (1), specific examples of preferable cation moieties are shown below.

[0036]

Chemical formula

[0037]

Chemical formula

[0038] Among the sulfonium salts represented by formula (2), specific examples of preferable cation moieties are shown below.

[0039]

Chemical formula

[0040]

Chemical formula

[0041] Among the sulfonium salts represented by formula (3), specific examples of preferable cation moieties are shown below.

[0042]

Chemical formula

[0043]

Chemical formula

[0044] Among the sulfonium salts represented by formulas (1) to (3), more preferable specific examples from the viewpoints of sensitivity and solubility are shown below.

[0045]

Chemical formula

[0046]

Chemical formula

[0047]

Chemical formula

[0048] In formulas (1) to (3), X is an atom (group) that can become a monovalent anion, that is, X - is an anion corresponding to the acid (HX) generated by irradiating the sulfonium salt with light (visible light, ultraviolet light, electron beam, X-ray, etc.). X - is not limited except that it is a monovalent polyatomic anion, but MY a - , (Rf) b PF 6-b - , R 8 c BY 4-c - , R 8 c GaY 4-c - , R 9 SO3 - , (R 9 SO2)3C - or (R 9 SO2)2N - represented anions are preferred.

[0049] M represents a phosphorus atom, a boron atom, or an antimony atom. Y represents a halogen atom (a fluorine atom is preferred.).

[0050] Rf represents an alkyl group in which 80 mol% or more of the hydrogen atoms are substituted with fluorine atoms (preferably an alkyl group having 1 to 8 carbon atoms). Examples of the alkyl group to be Rf by fluorine substitution include linear alkyl groups (such as methyl, ethyl, propyl, butyl, pentyl, and octyl), branched alkyl groups (such as isopropyl, isobutyl, sec-butyl, and tert-butyl), and cycloalkyl groups (such as cyclopropyl, cyclobutyl, cyclopentyl, and cyclohexyl). The proportion of the hydrogen atoms of 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 the hydrogen atoms originally possessed by the alkyl group. When the substitution ratio by fluorine atoms is within these preferable ranges, the photosensitivity of the sulfonium salt becomes even better. Particularly preferable Rf includes CF3-, CF3CF2-, (CF3)2CF-, CF3CF2CF2-, CF3CF2CF2CF2-, (CF3)2CFCF2-, CF3CF2(CF3)CF-, and (CF3)3C-. The b Rf's are independent of each other, and thus may be the same or different from each other.

[0051] P represents a phosphorus atom, and F represents a fluorine atom.

[0052] R 8 represents a phenyl group in which a part of the hydrogen atoms are substituted with at least one element or electron-withdrawing group. Examples of such an element include halogen atoms, such as fluorine atom, chlorine atom, and bromine atom. Examples of the electron-withdrawing group include trifluoromethyl group, nitro group, and cyano group. Among these, a phenyl group in which one hydrogen atom is substituted with a fluorine atom or a trifluoromethyl group is preferable. The c R's are independent of each other, and thus may be the same or different from each other. 8 are independent of each other, and thus may be the same or different from each other.

[0053] B represents a boron atom, and Ga represents a gallium atom.

[0054] R 9represents an alkyl group having 1 to 20 carbon atoms, a perfluoroalkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a fluorine atom. The alkyl group and the perfluoroalkyl group may be linear, branched, or cyclic, and the aryl group may be unsubstituted or may have a substituent.

[0055] 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 of 4 to 6. b is preferably an integer of 1 to 5, more preferably 2 to 4, and particularly preferably 2 or 3. c is preferably an integer of 1 to 4, and more preferably 4.

[0056] MY a - Examples of the anion represented by - include anions represented by SbF6 - , PF6 - , and BF4

[0057] (Rf) b PF 6-b - Examples of the anion represented by - include anions represented by (CF3CF2)2PF4 - , (CF3CF2)3PF3 - , ((CF3)2CF)2PF4 - , ((CF3)2CF)3PF3 - , (CF3CF2CF2)2PF4 - , (CF3CF2CF2)3PF3 - , ((CF3)2CFCF2)2PF4 - , ((CF3)2CFCF2)3PF3 - , (CF3CF2CF2CF2)2PF4 - and anions represented by (CF3CF2CF2CF2)3PF3 - Among these, (CF3CF2)3PF3 - , (CF3CF2CF2)3PF3 - , ((CF3)2CF)3PF3 - , ((CF3)2CF)2PF4 -, ((CF3)2CFCF2)3PF3 - and an anion represented by ((CF3)2CFCF2)2PF4 - is preferred.

[0058] R 8 c BY 4-c - Examples of the anion represented by (C6F5)4B - , ((CF3)2C6H3)4B - , (CF3C6H4)4B - , (C6F5)2BF2 - , C6F5BF3 - and an anion represented by (C6H3F2)4B - etc. Among these, an anion represented by (C6F5)4B - and an anion represented by ((CF3)2C6H3)4B - is preferred.

[0059] R 8 c GaY 4-c - Examples of the anion represented by (C6F5)4Ga - , ((CF3)2C6H3)4Ga - , (CF3C6H4)4Ga - , (C6F5)2GaF2 - , C6F5GaF3 - and an anion represented by (C6H3F2)4Ga - etc. Among these, an anion represented by (C6F5)4Ga - and an anion represented by ((CF3)2C6H3)4Ga - is preferred.

[0060] R 9 SO3 -Examples of the anion represented by include trifluoromethanesulfonate anion, pentafluoroethanesulfonate anion, heptafluoropropanesulfonate anion, nonafluorobutanesulfonate anion, pentafluorophenylsulfonate anion, fluorosulfonate anion, p-toluenesulfonate anion, benzenesulfonate anion, camphorsulfonate anion, methanesulfonate anion, ethanesulfonate anion, propanesulfonate anion, butanesulfonate anion, octanesulfonate anion, and the like. Among these, trifluoromethanesulfonate anion, nonafluorobutanesulfonate anion, methanesulfonate anion, butanesulfonate anion, camphorsulfonate anion, benzenesulfonate anion, and p-toluenesulfonate anion are preferred.

[0061] (R 9 SO2)3C - Examples of the anion represented by include (FSO2)3C - , (CF3SO2)3C - , (C2F5SO2)3C - , (C3F7SO2)3C - and (C4F9SO2)3C - and the like.

[0062] (R 9 SO2)2N - Examples of the anion represented by include (FSO2)2N - , (CF3SO2)2N - , (C2F5SO2)2N - , (C3F7SO2)2N - and (C4F9SO2)2N - and the like.

[0063] Examples of the monovalent polyatomic anion include MY a - , (Rf) b PF 6-b - , R 8 c BY 4-c- , R 8 c GaY 4-c - , R 9 SO3 - , (R 9 SO2)3C - or (R 9 SO2)2N - In addition to the anions represented by, perhalate ions (ClO4 - , BrO4 - , etc.), halogenated sulfonate ions (FSO3 - , ClSO3 - , etc.), sulfate ions (CH3SO4 - , CF3SO4 - , HSO4 - , etc.), carbonate ions (HCO3 - , CH3CO3 - , etc.), aluminate ions (AlCl4 - , AlF4 - , Al(OC4F9)4 - , etc.), hexafluorobismuthate ions (BiF6 - ), carboxylate ions (CH3COO - , CF3COO - , C6H5COO - , CH3C6H4COO - , C6F5COO - , CF3C6H4COO - , etc.), arylborate ions (B(C6H5)4 - , CH3CH2CH2CH2B(C6H5)3 - , etc.), thiocyanate ions (SCN - ) and nitrate ions (NO3 - ) etc. can be used.

[0064] Among these X - , MY a - , (Rf) b PF 6-b - , R 8 c BY 4-c - , R 8 c GaY4-c - , R 9 SO3 - , (R 9 SO2)3C - or (R 9 SO2)2N - An anion represented by is preferred, and SbF6 - , PF6 - , (CF3CF2)3PF3 - , ((CF3)2CF)3PF3 - , (CF3CF2CF2)3PF3 - , (C6F5)4B - , ((CF3)2C6H3)4B - , (C6F5)4Ga - , ((CF3)2C6H3)4Ga - , trifluoromethanesulfonate anion, nonafluorobutanesulfonate anion, methanesulfonate anion, butanesulfonate anion, camphorsulfonate anion, benzenesulfonate anion, p - toluenesulfonate anion, (FSO2)3C - , (CF3SO2)3C - , (FSO2)2N - and (CF3SO2)2N - are more preferred in terms of improving the resolution and pattern shape of the resist, and (CF3CF2)3PF3 - , ((CF3)2CF)3PF3 - , (CF3CF2CF2)3PF3 - , nonafluorobutanesulfonate anion, (C6F5)4B - and ((CF3)2C6H3)4B - , (CF3SO2)3C - is particularly preferred because of its better compatibility with the resist composition.

[0065] The sulfonium salts represented by formulas (1) to (3) can be produced by known production methods. For example, there are a method of reacting a diaryl sulfide with chlorine, a method of reacting a diaryl sulfide with chlorine and an aromatic hydrocarbon such as benzene, a method of reacting a diaryl sulfide with a diaryl iodonium salt under a copper catalyst, and a method of reacting a diaryl sulfide and a diaryl sulfoxide in the presence of a dehydrating agent.

[0066] There is no particular limitation on the dehydrating agent, and any dehydrating agent used in organic chemical reactions may be used. For example, concentrated sulfuric acid, phosphoric anhydride, methanesulfonic acid, trifluoromethanesulfonic acid or its anhydride, etc. may be mentioned, and two or more of these may be mixed and used. Also, a solvent may be used as appropriate.

[0067] When reacting a diaryl sulfoxide and a diaryl sulfide in the presence of a dehydrating agent, the molar ratio is sulfoxide:sulfide = 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 70°C, preferably 0°C to 50°C, and most preferably 10°C to 30°C.

[0068] After the reaction, the sulfonium salt can be efficiently produced by exchanging the anion with an acid (HX) and a salt (AXn) having the anion represented by X in formulas (1) to (3). Here, A is the counter cation of anion X - and n represents the number of anions X with respect to the valence of cation A. A represents an alkali metal such as Na, K, Li, an alkaline earth metal such as Mg, Ca, or an ammonium cation. An alkali metal is more preferable in terms of the ease of obtaining raw materials and the ease of purifying the sulfonium salt to be produced.

[0069] As a method for analyzing the content of the sulfonium salts represented by formulas (1) to (3) of the present invention, high performance liquid chromatography (HPLC) is used. To determine the content, the ratio of the total peak area of components (2) to (3) may be determined when the total peak area of each of components (1) to (3) obtained by the HPLC method is totaled and taken as 100. The measurement conditions of HPLC are as follows. Equipment: Model name (L-2130), Manufacturer (Hitachi), Column: (Ph-3), Manufacturer (GL Sciences Inc), Mobile phase: A solution of methanol: water: sodium perchlorate monohydrate = 600:68:20, Detector: UV (210 nm), Injection volume 10 μl, Column temperature 40 °C.

[0070] The content of the sulfonium salts (1) to (3) of the present invention is such that when the total area of the sulfonium salts represented by formulas (1) to (3) is taken as 100 according to the above content measurement method, the total area ratio of (2) and (3) is 0.02 or more and 5.5 or less. By containing a certain amount of sulfonium salts (2) and (3) relative to sulfonium salt (1), the storage stability of the composition at low temperatures is particularly improved. It is considered that the aggregation and precipitation of sulfonium salt (1) during low-temperature storage in the composition are prevented by containing a small amount of sulfonium salts (2) and (3).

[0071] In addition to the sulfonium salts listed above, the photoacid generator of the present invention may contain other conventionally known photoacid generators as required and be used. In the following, the photoacid generator of the present invention consists of the sulfonium salts represented by formulas (1) to (3) and does not contain other photoacid generators.

[0072] When containing other photoacid generators, the content (mol%) of the other photoacid generators is preferably 0.1 to 100, more preferably 0.5 to 50, based on the total number of moles of the sulfonium salts represented by formulas (1) to (3) of the present invention.

[0073] Examples of other photoacid generators include conventionally known ones such as salts of onium salts (sulfonium, iodonium, selenium, ammonium, phosphonium, etc.) and transition metal complex ions with anions.

[0074] In order to facilitate the dissolution of the photoacid generator of the present invention in cationically polymerizable compounds and chemically amplified resist compositions, it may be dissolved in a solvent that does not inhibit polymerization, crosslinking, deprotection reactions, etc. in advance.

[0075] As the solvent, 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 such as ethylene glycol, ethylene glycol monoacetate, diethylene glycol, diethylene glycol monoacetate, propylene glycol, propylene glycol monoacetate, dipropylene glycol and dipropylene glycol monoacetate and their derivatives; cyclic ethers such as dioxane; esters such as 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-methylbutyrate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate; aromatic hydrocarbons such as toluene and xylene, etc. may be mentioned.

[0076] When using a solvent, the usage ratio of the solvent is preferably 15 to 1000 parts by weight, more preferably 30 to 500 parts by weight, based on 100 parts by weight of the photoacid generator of the present invention. The solvent used may be used alone or in combination of two or more.

[0077] The photocurable composition of the present invention comprises the above photoacid generator and a cationic polymerizable compound.

[0078] Examples of the cationic polymerizable compound which is a constituent of the photocurable composition include cyclic ethers (such as epoxides and oxetanes), ethylenically unsaturated compounds (such as vinyl ethers and styrenes), bicyclic orthoesters, spiro orthocarbonates, and spiro orthoesters, etc. {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-A-2008-20839, JP-A-2008-20841, JP-A-2008-26660, JP-A-2008-26644, JP-A-2007-277327, Photopolymer Discussion Group, "Photopolymer Handbook" (1989, Industrial Research Institute), General Technology Center, "UV·EB Curing Technology" (1982, General Technology Center), Radtech Research Group, "UV·EB Curing Materials" (1992, CMC), Technical Information Association, "Causes of Curing Failure and Inhibition in UV Curing and Countermeasures Therefor" (2003, Technical Information Association), Color Materials, 68, (5), 286-293 (1995), Fine Chemicals, 29, (19), 5-14 (2000), etc.}

[0079] As the epoxide, known ones etc. can be used, and aromatic epoxides, alicyclic epoxides, and aliphatic epoxides are included.

[0080] Examples of the aromatic epoxide include glycidyl ethers of monovalent or polyvalent phenols having at least one aromatic ring (such as phenol, bisphenol A, phenol novolak, and compounds obtained by adding alkylene oxides thereto).

[0081] Examples of the alicyclic epoxide include compounds obtained by epoxidizing a compound having at least one cyclohexene or cyclopentene ring with an oxidizing agent (such as 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, etc.).

[0082] Examples of the aliphatic epoxide include polyglycidyl ethers of aliphatic polyhydric alcohols or their alkylene oxide adducts (such as 1,4 - butanediol diglycidyl ether and 1,6 - hexanediol diglycidyl ether), polyglycidyl esters of aliphatic polybasic acids (such as diglycidyl tetrahydrophthalate), and epoxidized products of long - chain unsaturated compounds (such as epoxidized soybean oil and epoxidized polybutadiene).

[0083] As the oxetane, known ones can be used. For example, 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, oxetanyl silsesquioxetane, and phenol novolak oxetane, etc. can be mentioned.

[0084] As the ethylenically unsaturated compound, known cationically polymerizable monomers etc. can be used, and it includes aliphatic monovinyl ethers, aromatic monovinyl ethers, polyfunctional vinyl ethers, styrene, and cationically polymerizable nitrogen - containing monomers.

[0085] Examples of the aliphatic monovinyl ether include methyl vinyl ether, ethyl vinyl ether, butyl vinyl ether, and cyclohexyl vinyl ether, etc.

[0086] Examples of the aromatic monovinyl ether include 2 - phenoxyethyl vinyl ether, phenyl vinyl ether, and p - methoxyphenyl vinyl ether, etc.

[0087] Examples of the polyfunctional vinyl ether include 1,4 - butanediol divinyl ether and triethylene glycol divinyl ether, etc.

[0088] Examples of styrene include styrene, α-methylstyrene, p-methoxystyrene, and p-tert-butoxystyrene.

[0089] Examples of cationically polymerizable nitrogen-containing monomers include N-vinylcarbazole and N-vinylpyrrolidone.

[0090] Examples of bicyclic 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.

[0091] 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.

[0092] 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.

[0093] Furthermore, a polyorganosiloxane having at least one cationically polymerizable group in one molecule can be used (described in JP-A-2001-348482, JP-A-2000-281965, JP-A-7-242828, JP-A-2008-195931, Journal of Polym. Sci., Part A, Polym. Chem., Vol. 28, 497 (1990), etc.). These polyorganosiloxanes may be linear, branched, cyclic, or a mixture thereof.

[0094] Among these cationically polymerizable compounds, epoxides, oxetanes and vinyl ethers are preferred, more preferably epoxides and oxetanes, and particularly preferably alicyclic epoxides and oxetanes. These cationically polymerizable compounds may be used alone or in combination of two or more thereof.

[0095] The content of the photoacid generator of the present invention in the photocurable composition is preferably 0.05 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of the cationically polymerizable compound. Within this range, the polymerization of the cationically polymerizable compound becomes more sufficient and the physical properties of the cured body become better. Note that this content is determined by considering various factors such as the properties of the cationically polymerizable compound, the type of light (light source, wavelength, etc.) and irradiation amount, temperature, curing time, humidity, thickness of the coating film, etc., and is not limited to the above range.

[0096] The photocurable composition of the present invention may contain, if necessary, known additives (sensitizers, pigments, fillers, antistatic agents, flame retardants, defoaming agents, flow regulators, light stabilizers, antioxidants, adhesion promoters, ion scavengers, anti-coloring agents, solvents, non-reactive resins, radical polymerizable compounds, etc.).

[0097] As the sensitizer, known sensitizers (such as JP-A-11-279212 and JP-A-09-183960, etc.) can be used, and examples include 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-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, 2,4-diethylthioxanthone, etc.}; phenothiazine {phenothiazine, N-methylphenothiazine, N-ethylphenothiazine, N-phenylphenothiazine, etc.}; xanthone; naphthalene {1-naphthol, 2-naphthol, 1-methoxynaphthalene, 2-methoxynaphthalene, 1,4-dihydroxynaphthalene, and 4-methoxy-1-naphthol, etc.}; ketone {dimethoxyacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4'-isopropyl-2-hydroxy-2-methylpropiophenone, and 4-benzoyl-4'-methyldiphenyl sulfide, etc.}; carbazole {N-phenylcarbazole, N-ethylcarbazole, poly-N-vinylcarbazole, and N-glycidylcarbazole, etc.}; chrysene {1,4-dimethoxychrysene and 1,4-di-α-methylbenzyloxychrysene, etc.}; phenanthrene {9-hydroxyphenanthrene, 9-methoxyphenanthrene, 9-hydroxy-10-methoxyphenanthrene, and 9-hydroxy-10-ethoxyphenanthrene, etc.} and the like.

[0098] When containing a sensitizer, the content of the sensitizer is preferably 1 to 300 parts by weight, more preferably 5 to 200 parts by weight, based on 100 parts of the photoacid generator.

[0099] As the pigment, known pigments and the like can be used, and examples include inorganic pigments (such as titanium oxide, iron oxide, and carbon black) and organic pigments (such as azo pigments, cyanine pigments, phthalocyanine pigments, and quinacridone pigments).

[0100] When containing a pigment, the content of the pigment is preferably 0.5 to 400,000 parts by weight, more preferably 10 to 150,000 parts by weight, based on 100 parts of the photoacid generator.

[0101] As the filler, known fillers etc. can be used, and examples include fused silica, crystalline silica, calcium carbonate, aluminum oxide, aluminum hydroxide, zirconium oxide, magnesium carbonate, mica, talc, calcium silicate, and lithium aluminum silicate.

[0102] When containing a filler, the content of the filler is preferably 50 to 600,000 parts by weight, more preferably 300 to 200,000 parts by weight, based on 100 parts of the photoacid generator.

[0103] As the antistatic agent, known antistatic agents etc. can be used, and examples include nonionic antistatic agents, anionic antistatic agents, cationic antistatic agents, amphoteric antistatic agents, and polymeric antistatic agents.

[0104] When containing an antistatic agent, 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, based on 100 parts of the photoacid generator.

[0105] As the flame retardant, known flame retardants etc. can be used, and examples include inorganic flame retardants {antimony trioxide, antimony pentoxide, tin oxide, tin hydroxide, molybdenum oxide, zinc borate, barium metaborate, red phosphorus, aluminum hydroxide, magnesium hydroxide, and calcium aluminate etc.}; bromine flame retardants {tetrabromo phthalic anhydride, hexabromobenzene, and decabromodiphenyl ether etc.}; and phosphate ester flame retardants {tris(tribromophenyl) phosphate etc.} etc.

[0106] When containing a flame retardant, the content of the flame retardant is preferably 0.5 to 40,000 parts by weight, more preferably 5 to 10,000 parts by weight, based on 100 parts of the photoacid generator.

[0107] As the defoaming agent, known defoaming agents and the like can be used, and examples include 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.

[0108] As the flow regulator, known fluidity regulators and the like can be used, and examples include hydrogenated castor oil, polyethylene oxide, organic bentonite, colloidal silica, amide wax, metal soap, and acrylate polymer. As the light stabilizer, known light stabilizers and the like can be used, and examples include ultraviolet absorber type stabilizers {benzotriazole, benzophenone, salicylate, cyanoacrylate, and their derivatives, etc.}; radical scavenging type stabilizers {hindered amines, etc.}; and quenching type stabilizers {nickel complexes, etc.}. As the antioxidant, known antioxidants and the like can be used, and examples include phenolic antioxidants (monophenolic, bisphenolic, and high molecular phenolic, etc.), sulfur-based antioxidants, and phosphorus-based antioxidants. As the adhesion promoter, known adhesion promoters and the like can be used, and examples include coupling agents, silane coupling agents, and titanium coupling agents. As the ion supplement agent, known ion supplement agents and the like can be used, and examples include organic aluminum (alkoxy aluminum, phenoxy aluminum, etc.). As the anti-coloring agent, known anti-coloring agents can be used. Generally, antioxidants are effective, and examples include phenolic antioxidants (monophenolic, bisphenolic, and high molecular phenolic, etc.), sulfur-based antioxidants, and phosphorus-based antioxidants. However, they have little effect on preventing coloring during the heat resistance test at high temperatures.

[0109] When containing a defoaming agent, a flow regulator, a light stabilizer, an antioxidant, an adhesion promoter, an ion supplement agent, or an anti-coloring agent, the content of each is preferably 0.1 to 20,000 parts by weight, more preferably 0.5 to 5,000 parts by weight, based on 100 parts of the photoacid generator.

[0110] As the solvent, there is no limitation as long as it can be used for dissolving the cationically polymerizable compound and adjusting the viscosity of the photocurable composition, and those mentioned as the solvent for the above photoacid generator can be used.

[0111] When containing a solvent, the content of the solvent is preferably 50 to 2,000,000 parts by weight, more preferably 200 to 500,000 parts by weight, based on 100 parts by weight of the photoacid generator.

[0112] Examples of the non-reactive resin include polyester, polyvinyl acetate, polyvinyl chloride, polybutadiene, polycarbonate, polystyrene, polyvinyl ether, polyvinyl butyral, polybutene, hydrogenated styrene-butadiene block copolymer, copolymer of (meth)acrylate ester, and polyurethane. The number average molecular weight of these resins is preferably 1000 to 500,000, more preferably 5000 to 100,000 (the number average molecular weight is a value measured by a general method such as GPC).

[0113] When containing a non-reactive resin, the content of the non-reactive resin is preferably 5 to 400,000 parts by weight, more preferably 50 to 150,000 parts by weight, based on 100 parts by weight of the photoacid generator.

[0114] When adding a non-reactive resin, in order to make it easier to dissolve the non-reactive resin with the cationically polymerizable compound, etc., it is desirable to dissolve it in a solvent in advance.

[0115] As the radically polymerizable compound, known radically polymerizable compounds {such as those compiled by the Photopolymerization Symposium (Photopolymer Handbook, 1989, Industrial Research Society), the General Technology Center (UV / EB Curing Technology, 1982, General Technology Center), the Radtech Research Group (UV / EB Curing Materials, 1992, CMC), and the Technical Information Association (Causes of Curing Defects and Inhibitions in UV Curing and Their Countermeasures, 2003, Technical Information Association)} can be used, including monofunctional monomers, difunctional monomers, polyfunctional monomers, epoxy (meth)acrylate, polyester (meth)acrylate, and urethane (meth)acrylate.

[0116] When containing a radically polymerizable compound, the content of the radically polymerizable compound is preferably 5 to 400,000 parts by weight, more preferably 50 to 150,000 parts by weight, based on 100 parts of the photoacid generator.

[0117] When containing a radically polymerizable compound, in order to increase the molecular weight of these by radical polymerization, it is preferable to use a radical polymerization initiator that initiates polymerization by heat or light.

[0118] As the radical polymerization initiator, known radical polymerization initiators and the like can be used, and include thermal radical polymerization initiators (organic peroxides, azo compounds, etc.) and photo radical polymerization initiators (acetophenone-based initiators, benzophenone-based initiators, Michler's ketone-based initiators, benzoin-based initiators, thioxanthone-based initiators, acylphosphine-based initiators, etc.).

[0119] When containing a radical polymerization initiator, 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, based on 100 parts of the radically polymerizable compound.

[0120] The photocurable composition of the present invention can be prepared by uniformly mixing and dissolving a cationically polymerizable compound, a photoacid generator, and, if necessary, additives at room temperature (about 20 to 30 ° C) or, if necessary, by heating (about 40 to 90 ° C), or further kneading with a three-roll mill or the like.

[0121] The photocurable composition of the present invention can be cured by light irradiation to obtain a cured body. As the light used here, any light may be used as long as it has energy to induce the decomposition of the photoacid generator of the present invention. However, ultraviolet to visible light (wavelength: about 100 to about 800 nm) obtained from a low-pressure, medium-pressure, high-pressure or ultra-high-pressure mercury lamp, metal halide lamp, LED lamp, xenon lamp, carbon arc lamp, fluorescent lamp, semiconductor solid laser, argon laser, He-Cd laser, KrF excimer laser, ArF excimer laser or F2 laser, etc. is preferred. In addition, as the light, radiation having high energy such as electron beam or X-ray can also be used.

[0122] The irradiation time of light is affected by the intensity of the light source and the light transmittance of the photocurable composition. However, at room temperature (about 20 to 30 °C), about 0.1 second to about 10 seconds is sufficient. However, in the case of low light transmittance or thick film thickness of the photocurable composition, it may be preferable to take more time. Most photocurable compositions cure by cationic polymerization 0.1 second to several minutes after light irradiation. However, if necessary, after light irradiation, it is also possible to perform after-cure by heating at room temperature (about 20 to 30 °C) to 200 °C for several seconds to several hours.

[0123] Specific uses of the photocurable composition of the present invention include paints, coating agents, various coating materials (hard coats, stain-resistant coatings, anti-fog coatings, corrosion-resistant coatings, optical fibers, etc.), backside treatment agents for adhesive tapes, release coating materials for release sheets for adhesive labels (release papers, release plastic films, release metal foils, etc.), printed boards, dental materials (dental formulations, dental composites), inks, inkjet inks, positive resists (for forming connection terminals and wiring patterns in the manufacture of electronic components such as circuit boards, CSPs, MEMS elements, etc.), resist films, liquid resists, negative resists (permanent film materials such as surface protection films, interlayer insulating films, planarization films for semiconductor elements, etc.), resists for MEMS, positive 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 (such as deflection plates, antireflection films, etc.)), holographic resins, FPD materials (color filters, black matrices, partition materials, photo spacers, ribs, alignment films for liquid crystals, sealants for FPDs, etc.), optical members, molding materials (for building materials, optical parts, lenses), casting materials, putties, glass fiber impregnants, caulking materials, sealing materials, encapsulants for optical semiconductors (LEDs), optical waveguide materials, nanoimprint materials, materials for optical lithography, and materials for microstereolithography, etc. In particular, since the obtained cured product has little coloring and excellent transparency, it is most suitable for optical applications.

[0124] Since the photoacid generator of the present invention generates a strong acid upon light irradiation, it can also be used as a photoacid generator for known (Japanese Patent Application Laid-Open Nos. 2003-267968, 2003-261529, 2002-193925, etc.) chemically amplified resist materials.

[0125] As chemically amplified resist materials, there are included: (1) a two-component chemically amplified positive resist containing, as essential components, a resin which becomes soluble in an alkaline developer by the action of an acid and a photoacid generator; (2) a three-component chemically amplified positive resist containing, as essential components, a resin soluble in an alkaline developer, a dissolution inhibitor which becomes soluble in an alkaline developer by the action of an acid, and a photoacid generator; and (3) a chemically amplified negative resist containing, as essential components, a resin soluble in an alkaline developer, a crosslinking agent which crosslinks the resin by heat treatment in the presence of an acid to make it insoluble in an alkaline developer, and a photoacid generator.

[0126] The chemically amplified positive photoresist composition of the present invention is characterized by containing a component (A) comprising the photoacid generator of the present invention which is a compound that generates an acid upon light irradiation, and a resin component (B) whose solubility in alkali increases by the action of an acid.

[0127] 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, for example, onium salt compounds, sulfone compounds, sulfonic acid ester compounds, sulfonimide compounds, disulfonyldiazomethane compounds, disulfonylmethane compounds, oxime sulfonate compounds, hydrazine sulfonate compounds, triazine compounds, nitrobenzyl compounds, as well as organic halides, disulfones, and the like.

[0128] As other conventionally known photoacid generators, preferably, one or more of the group consisting of onium compounds, sulfonimide compounds, diazomethane compounds, and oxime sulfonate compounds are preferred.

[0129] When using such other conventionally known photoacid generators in combination, the usage ratio may be arbitrary, but usually, with respect to 100 parts by weight in total of the photoacid generator of the present invention, the other photoacid generator is 10 to 900 parts by weight, preferably 25 to 400 parts by weight.

[0130] The content of the above component (A) is preferably 0.05 to 5% by weight in the solid content of the chemically amplified positive photoresist composition.

[0131] <Resin component (B) whose solubility in alkali increases due to the action of an acid> The above-mentioned "resin (B) whose solubility in alkali increases due to the action of an acid" (hereinafter referred to as "component (B)") used in the chemically amplified positive photoresist composition for thick films of the present invention is at least one resin selected from the group consisting of novolak resin (B1), polyhydroxystyrene resin (B2), and acrylic resin (B3), or a mixed resin or copolymer thereof.

[0132] [Novolak resin (B1)] As the novolak resin (B1), a resin represented by the following general formula (b1) can be used.

[0133] [Chemical formula]

[0134] In the above general formula (b1), R 1b represents an acid-dissociable dissolution-inhibiting group, and R 2b , R 3b each independently represents 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.

[0135] Furthermore, as the acid-dissociable dissolution-inhibiting group represented by the above R 1b , 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 is preferable.

[0136] Here, the above R 1bSpecific examples of the acid-dissociable dissolution-inhibiting group represented by [the formula] 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, among others.

[0137] [Polyhydroxystyrene resin (B2)] As the polyhydroxystyrene resin (B2), a resin represented by the following general formula (b4) can be used.

[0138] [Chemical formula]

[0139] 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 repeating unit number of the structure within the parentheses.

[0140] The above 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, and examples include 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, a neopentyl group, etc. Examples of the cyclic alkyl group include a cyclopentyl group, a cyclohexyl group, etc.

[0141] As the acid-dissociable dissolution-inhibiting group represented by the above R 9b , the same acid-dissociable dissolution-inhibiting groups as those exemplified for the above R 1b can be used.

[0142] Furthermore, the polyhydroxystyrene resin (B2) can contain other polymerizable compounds as constituent units for the purpose of appropriately controlling physical and chemical properties. Examples of such polymerizable compounds include known radical-polymerizable compounds and anionic-polymerizable compounds. For example, 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; amide bond-containing polymerizable compounds such as acrylamide, and the like can be mentioned.

[0143] [Acrylic resin (B3)] As the acrylic resin (B3), resins represented by the following general formulas (b5) to (b10) can be used.

[0144] [Chemical formula]

[0145] [Chemical formula]

[0146] In the above general formulas (b5) to (b7), R 10b ~R 17b each independently represents 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, and X bforms a hydrocarbon ring having 5 to 20 carbon atoms together with the carbon atom to which it is attached, and Y b represents an aliphatic cyclic group or an 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.

[0147] 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 independently represents 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 independently represents a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof, 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 a divalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof together with the common carbon atom to which each is attached, and the remaining R 22b represents a linear alkyl group having 1 to 4 carbon atoms, a branched alkyl group having 3 to 4 carbon atoms, a monovalent alicyclic hydrocarbon group having 4 to 20 carbon atoms or a derivative thereof.

[0148] Among the above component (B), it is preferable to use an acrylic resin (B3).

[0149] In addition, the polystyrene-reduced weight average molecular weight of component (B) is preferably from 10,000 to 600,000, more preferably from 50,000 to 600,000, and still more preferably from 230,000 to 550,000. By setting the weight average molecular weight to such a value, the resin physical properties of the resist become excellent.

[0150] Furthermore, component (B) is preferably a resin having a dispersity of 1.05 or more. Here, the "dispersity" is the value obtained by dividing the weight average molecular weight by the number average molecular weight. By setting the dispersity to such a value, the plating resistance and resin physical properties of the resist become excellent.

[0151] The content of the above component (B) is preferably 5 to 60% by weight in the solid content of the chemically amplified positive photoresist composition.

[0152] <Alkali-soluble resin (C)> In the chemically amplified positive photoresist composition of the present invention, in order to improve the resin physical properties of the resist, it is preferable to further contain an alkali-soluble resin (hereinafter referred to as "component (C)" in this specification). As component (C), it is preferably at least one selected from the group consisting of novolak resins, polyhydroxystyrene resins, acrylic resins, and polyvinyl resins.

[0153] The content of the above component (C) is preferably 5 to 95 parts by weight, more preferably 10 to 90 parts by weight, based on 100 parts by weight of the above component (B). By setting it to 5 parts by weight or more, the resin physical properties of the resist can be improved, and by setting it to 95 parts by weight or less, there is a tendency to prevent film loss during development.

[0154] <Acid diffusion controller (D)> In the chemically amplified positive photoresist composition for thick films of the present invention, in order to improve the resist pattern shape, standing stability, etc., it is preferable to further contain an acid diffusion control agent (D) (referred to as "component (D)" in this specification). As the component (D), a nitrogen-containing compound is preferable, and if necessary, an organic carboxylic acid, an oxo acid of phosphorus or a derivative thereof can be further contained.

[0155] Further, the chemically amplified positive photoresist composition of the present invention can further contain an adhesion aid in order to improve the adhesion to the substrate. As the adhesion aid to be used, a functional silane coupling agent is preferable.

[0156] Further, the chemically amplified positive photoresist composition of the present invention can further contain a surfactant in order to improve coatability, defoaming property, leveling property, etc.

[0157] Further, the chemically amplified positive photoresist composition of the present invention can further contain an acid, an acid anhydride, or a high-boiling solvent in order to finely adjust the solubility in an alkaline developer.

[0158] Moreover, the chemically amplified positive photoresist composition of the present invention basically does not require a sensitizer, but a sensitizer can be contained as necessary to complement the sensitivity. As such a sensitizer, conventionally known ones can be used, and specifically, those described above can be mentioned.

[0159] The amount of these sensitizers used is 5 to 500 parts by weight, preferably 10 to 300 parts by weight, based on 100 parts by weight of the total weight of the photoacid generator of the present invention.

[0160] Further, an organic solvent can be appropriately blended in the chemically amplified positive photoresist composition of the present invention for viscosity adjustment. Specific examples of the organic solvent are those described above.

[0161] The amount of these organic solvents used is preferably in the range where the solid content concentration is 30% by weight or more so that the film thickness of the photoresist layer obtained by using the chemically amplified positive photoresist composition of the present invention (for example, by the spin coating method) is 5 μm or more.

[0162] The preparation of the chemically amplified positive photoresist composition for thick films of the present invention may be carried out, for example, by simply mixing and stirring the above components in a conventional manner, and if necessary, dispersing and mixing them using a disperser such as a dissolver, a homogenizer, or a three-roll mill. Further, after mixing, filtration may be carried out using a mesh, a membrane filter, or the like.

[0163] The chemically amplified positive photoresist composition of the present invention is suitable for forming a photoresist layer having a film thickness of usually 5 to 150 μm, more preferably 10 to 120 μm, and still more preferably 10 to 100 μm on a support. This photoresist laminate has a photoresist layer composed of the chemically amplified positive photoresist composition of the present invention laminated on a support.

[0164] The support is not particularly limited, and conventionally known ones can be used. For example, substrates for electronic components and those having a predetermined wiring pattern formed thereon can be exemplified. Examples of such substrates include metal substrates such as silicon, silicon nitride, titanium, tantalum, palladium, titanium tungsten, copper, chromium, iron, and aluminum, and glass substrates. In particular, the chemically amplified positive photoresist composition of the present invention can form a resist pattern well even on a copper substrate. Examples of the material for the wiring pattern include copper, solder, chromium, aluminum, nickel, and gold.

[0165] The above photoresist laminate can be manufactured, for example, as follows. That is, a solution of the chemically amplified positive photoresist composition prepared as described above is applied onto a support, and a desired coating film is formed by removing the solvent by heating. As a method for applying onto the support, methods such as spin coating method, slit coating method, roll coating method, screen printing method, applicator method, etc. can be adopted. The pre-bake conditions of the coating film of the composition of the present invention vary depending on the type, blending ratio, coating film thickness, etc. of each component in the composition, but usually it may be about 70 to 150 °C, preferably 80 to 140 °C, for about 2 to 60 minutes.

[0166] The film thickness of the photoresist layer is usually in the range of 5 to 150 μm, preferably 10 to 120 μm, more preferably 10 to 100 μm.

[0167] To form a resist pattern using the photoresist laminate thus obtained, the obtained photoresist layer may be selectively irradiated (exposed) with light or radiation, for example, ultraviolet light or visible light having a wavelength of 300 to 500 nm, through a mask having a predetermined pattern.

[0168] Here, "light" is synonymous with actinic energy ray, and any light that activates the photoacid generator to generate an acid may be used, including ultraviolet light, visible light, far ultraviolet light, and "radiation" means X-ray, electron beam, ion beam, etc. As a light source or radiation source, a low-pressure mercury lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, metal halide lamp, argon gas laser, LED lamp, etc. can be used. Also, the radiation dose varies depending on the type, blending amount, film thickness of the coating film, etc. of each component in the composition. For example, in the case of using an ultra-high-pressure mercury lamp, it is 50 to 10,000 mJ / cm 2 is.

[0169] After exposure, heating is performed using a known method to promote the diffusion of the acid, thereby changing the alkali solubility of the photoresist layer in the exposed portion. Then, for example, using a predetermined alkaline aqueous solution as a developer, unnecessary portions are dissolved and removed to obtain a predetermined resist pattern.

[0170] The development time varies depending on the type and blending ratio of each component of the composition and the dry film thickness of the composition, but is usually 1 to 30 minutes. Also, the development method may be any of the puddle method, dipping method, paddle method, spray development method, etc. After development, running water washing is performed for 30 to 90 seconds, and drying is performed using an air gun, an oven, or the like.

[0171] By embedding a conductor such as a metal, for example, by plating, etc. in the non-resist portion (the portion removed by the alkali developer) of the resist pattern thus obtained, connection terminals such as metal posts and bumps can be formed. The plating treatment method is not particularly limited, and various conventionally known methods can be adopted. As the plating solution, in particular, solder plating, copper plating, gold plating, and nickel plating solutions are preferably used. The remaining resist pattern is finally removed using a stripping solution or the like according to a conventional method.

[0172] The chemically amplified positive photoresist composition of the present invention can also be used as a dry film. This dry film has protective films formed on both sides of a layer made of the chemically amplified positive photoresist composition of the present invention. The film thickness of the layer made of the chemically amplified positive photoresist composition is usually in the range of 10 to 150 μm, preferably 20 to 120 μm, and more preferably 20 to 80 μm. Also, the protective film is not particularly limited, and a resin film conventionally used for dry films can be used. As an example, one side can be a polyethylene terephthalate film, and the other side can be one selected from the group consisting of a polyethylene terephthalate film, a polypropylene film, and a polyethylene film.

[0173] The chemically amplified positive dry film as described above can be manufactured, for example, in the following manner. That is, a solution of the chemically amplified positive photoresist composition prepared as described above is applied onto one of the protective films, and a desired coating film is formed by removing the solvent by heating. The drying conditions vary depending on the type of each component in the composition, the blending ratio, the coating film thickness, etc., but usually it may be at 60 to 100 °C for about 5 to 20 minutes.

[0174] To form a resist pattern using the chemically amplified dry film thus obtained, one of the protective films of the chemically amplified positive dry film is peeled off, and it is laminated onto the support with the exposed surface facing the support side as described above to obtain a photoresist layer. Then, after performing pre-baking to dry the resist, the other protective film may be peeled off.

[0175] For the photoresist layer obtained on the support in this way, a resist pattern can be formed in the same manner as described above for the photoresist layer formed by directly applying it onto the support.

[0176] The chemically amplified negative photoresist composition of the present invention is characterized by containing a component (E) comprising a photoacid generator of the present invention which is a compound that generates an acid upon irradiation with light or radiation, an alkali-soluble resin (F) having a phenolic hydroxyl group, and a crosslinking agent (G).

[0177] In the chemically amplified negative photoresist composition of the present invention, the component (E) may be used in combination with other conventionally known photoacid generators. Examples of other photoacid generators include, for example, onium salt compounds, sulfone compounds, sulfonic acid ester compounds, sulfonimide compounds, disulfonyldiazomethane compounds, disulfonylmethane compounds, oxime sulfonate compounds, hydrazine sulfonate compounds, triazine compounds, nitrobenzyl compounds, and in addition, organic halides, disulfones, etc.

[0178] As other conventionally known photoacid generators, preferably, one or more selected from the group consisting of onium compounds, sulfonimide compounds, diazomethane compounds, and oxime sulfonate compounds are preferred.

[0179] When such other conventionally known photoacid generators are used in combination, the usage ratio may be arbitrary, but usually, with respect to 100 parts by weight of the total weight of the photoacid generator of the present invention, the other photoacid generator is 10 to 900 parts by weight, preferably 25 to 400 parts by weight.

[0180] The content of the above component (E) is preferably 0.01 to 10% by weight in the solid content of the chemically amplified negative photoresist composition.

[0181] Alkali-soluble resin (F) having a phenolic hydroxyl group The "alkali-soluble resin having a phenolic hydroxyl group" (hereinafter referred to as "phenolic resin (F)") in the present invention includes, for example, novolak resin, polyhydroxystyrene, copolymer of polyhydroxystyrene, copolymer of hydroxystyrene and styrene, copolymer of hydroxystyrene, styrene and (meth)acrylic acid derivative, phenol-xylylene glycol condensation resin, cresol-xylylene glycol condensation resin, phenol-dicyclopentadiene condensation resin, etc. Among these, novolak resin, polyhydroxystyrene, copolymer of polyhydroxystyrene, copolymer of hydroxystyrene and styrene, copolymer of hydroxystyrene, styrene and (meth)acrylic acid derivative, phenol-xylylene glycol condensation resin are preferred. In addition, these phenolic resins (F) may be used alone or in combination of two or more.

[0182] Further, the above phenolic resin (F) may contain a phenolic low molecular compound as a part of the components. Examples of the above phenolic low molecular compound include 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl ether, etc.

[0183] Crosslinking agent (G) The "crosslinking agent" in the present invention (hereinafter also referred to as "crosslinking agent (G)") is not particularly limited as long as it acts as a crosslinking component (hardening component) that reacts with the phenol resin (F). Examples of the crosslinking agent (G) include compounds having at least two or more alkyl-etherified amino groups in the molecule, compounds having a benzene skeleton with at least two or more alkyl-etherified groups in the molecule, oxirane ring-containing compounds, thiirane ring-containing compounds, oxetanyl group-containing compounds, isocyanate group-containing compounds (including blocked ones), and the like.

[0184] Among these crosslinking agents (G), compounds having at least two or more alkyl-etherified amino groups in the molecule and oxirane ring-containing compounds are preferable. More preferably, a compound having at least two or more alkyl-etherified amino groups in the molecule and an oxirane ring-containing compound are used in combination.

[0185] The blending 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, based on 100 parts by weight of the phenol resin (F). When the blending amount of this crosslinking agent (G) is 1 to 100 parts by weight, the curing reaction proceeds sufficiently, and the obtained cured product has a good pattern shape with high resolution and is excellent in heat resistance and electrical insulation, which is preferable. When a compound having an alkyl-etherified amino group and an oxirane ring-containing compound are used in combination, the content ratio of the oxirane ring-containing compound is preferably 50% by weight or less, more preferably 5 to 40% by weight, particularly preferably 5 to 30% by weight, when the total of the compound having an alkyl-etherified amino group and the oxirane ring-containing compound is 100% by weight. In this case, the obtained cured film is preferable because it is excellent in chemical resistance without impairing high resolution.

[0186] Crosslinked fine particles (H) In the chemically amplified negative photoresist composition of the present invention, crosslinked fine particles (hereinafter, also referred to as "crosslinked fine particles (H)") can be further contained in order to improve the durability and thermal shock resistance of the obtained cured product.

[0187] 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 fine particles (H) is not particularly limited. For example, when synthesizing the crosslinked fine particles by emulsion polymerization, the number of micelles during emulsion polymerization can be controlled by the amount of emulsifier used, and the particle size can be controlled. The average particle size of the crosslinked fine particles (H) is a value measured by diluting a dispersion of the crosslinked fine particles according to a conventional method using a light scattering flow distribution measuring device or the like.

[0188] The compounding amount of the crosslinked fine particles (H) is preferably 0.5 to 50 parts by weight, more preferably 1 to 30 parts by weight, based on 100 parts by weight of the phenol resin (F). When the compounding amount of the crosslinked fine particles (H) is 0.5 to 50 parts by weight, the compatibility or dispersibility with other components is excellent, and the thermal shock resistance and heat resistance of the obtained cured film can be improved.

[0189] Adhesion aid In addition, the chemically amplified negative photoresist composition of the present invention can contain an adhesion aid in order to improve the adhesion to the substrate. Examples of the adhesion aid include functional silane coupling agents having reactive substituents such as carboxyl group, methacryloyl group, isocyanate group, epoxy group, etc.

[0190] The compounding amount of the adhesion aid is preferably 0.2 to 10 parts by weight, more preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the phenol resin (F). When the compounding amount of the adhesion aid is 0.2 to 10 parts by weight, it is preferable because it has excellent storage stability and can obtain good adhesion.

[0191] Solvent In addition, the chemically amplified negative photoresist composition of the present invention can contain a solvent in order to improve the handleability of the resin composition or to adjust the viscosity and storage stability. The solvent is not particularly limited, and specific examples include those described above.

[0192] Other additives Moreover, the chemically amplified negative photoresist composition of the present invention can contain other additives to such an extent that the characteristics of the present invention are not impaired, if necessary. Examples of such other additives include inorganic fillers, sensitizers, quenchers, leveling agents / surfactants, and the like.

[0193] The method for preparing the chemically amplified negative photoresist composition of the present invention is not particularly limited and can be prepared by a known method. Also, it can be prepared by placing each component in a sample bottle with a complete stopper and stirring it on a rotary shaker.

[0194] The cured product in the present invention is characterized in that the chemically amplified negative photoresist composition is cured. The chemically amplified negative photoresist composition according to the present invention described above has a high residual film ratio and excellent resolution, and its cured product is excellent in electrical insulation, thermal shock resistance, etc. Therefore, the cured product can be suitably used as a surface protective film, a planarization film, an interlayer insulating film material, etc. for electronic components such as semiconductor elements and semiconductor packages.

[0195] To form the cured product of the present invention, first, the chemically amplified negative photoresist composition according to the present invention described above is applied to a support (such as a copper foil with resin, a copper-clad laminate, a silicon wafer with a metal sputter film, an alumina substrate, etc.), dried to volatilize solvents and the like, and a coating film is formed. Then, it is exposed through a desired mask pattern, and heat treatment (hereinafter, this heat treatment is referred to as "PEB") is performed to promote the reaction between the phenolic resin (F) and the crosslinking agent (G). Next, development is carried out with an alkaline developer to dissolve and remove the unexposed portions, thereby obtaining a desired pattern. Furthermore, a cured film can be obtained by performing heat treatment to develop insulating film characteristics.

[0196] As a method for applying the resin composition to the support, for example, coating methods such as dipping method, spraying method, bar coating method, roll coating method, or spin coating method can be used. Also, the thickness of the coating film can be appropriately controlled by adjusting the coating means, the solid content concentration, and the viscosity of the composition solution. Examples of the radiation used for exposure include ultraviolet rays such as 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, electron beams, laser beams, etc. Also, the exposure amount is appropriately selected depending on the light source used, the resin film thickness, etc. For example, in the case of ultraviolet irradiation from a high-pressure mercury lamp, when the resin film thickness is 1 to 50 μm, it is about 100 to 50000 J / m 2 degree.

[0197] After exposure, the above PEB treatment is performed to promote the curing reaction between the phenolic resin (F) and the crosslinking agent (G) by the generated acid. The PEB conditions vary depending on the blending amount of the resin composition, the film thickness used, etc., but usually, it is at 70 to 150 °C, preferably 80 to 120 °C, for about 1 to 60 minutes. Then, development is carried out with an alkaline developer to dissolve and remove the unexposed portions to form a desired pattern. Examples of the development method in this case include shower development method, spray development method, immersion development method, paddle development method, etc. The development conditions are usually at 20 to 40 °C for about 1 to 10 minutes.

[0198] Furthermore, in order to fully exhibit the properties of the insulating film after development, it can be sufficiently cured by performing a heat treatment. Such curing conditions are not particularly limited, but depending on the use of the cured product, it can be cured by heating at a temperature of 50 to 250 ° C for about 30 minutes to 10 hours. In addition, in order to sufficiently advance the curing or prevent deformation of the obtained pattern shape, it is also possible to heat in two stages. For example, in the first stage, it is heated at a temperature of 50 to 120 ° C for about 5 minutes to 2 hours, and further at a temperature of 80 to 250 ° C for about 10 minutes to 10 hours to cure. Under such curing conditions, a general oven, an infrared furnace, etc. can be used as the heating equipment.

Examples

[0199] Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited thereto. In addition, parts in each example indicate parts by weight.

[0200] 〔Production Example 1〕 Synthesis of sulfonium salt mixture (PAG-1) 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 uniformly mixed. Then, 36 g of diphenyl sulfide was added dropwise. Although the temperature increased due to exotherm during the process, it was cooled so as not to exceed the temperature of 40 ° C. After stirring at 40 ° C for 1 hour, it was cooled to room temperature, 200 mL of water was added and stirred for 10 minutes, and then an oily substance was separated. 200 mL of ethyl acetate was added thereto to dissolve the oily substance, and the organic layer was separated. This organic layer was washed 3 times with 100 mL of 20% caustic soda and further 100 mL of water, and then acetonitrile and ethyl acetate were distilled off under reduced pressure to obtain a pale yellow solid. After washing with methanol and hexane, 90 g (yield 94%) of a white solid was obtained. By analysis using H-NMR, C-NMR, and HPLC, it was confirmed that this white solid was a mixture of hexafluorophosphates having the cation structures of (C1-1) to (C1-3), and the ratio thereof was 98.85:0.03:1.12.

[0201] Manufacturing Example 2: Synthesis of Sulfonium Salt Mixture (PAG-2) A white solid (96 g, yield 85%) was obtained in the same manner as in Manufacturing Example 1, except that 43 g of potassium hexafluorophosphate was changed to 55 g of potassium hexafluoroantimonate. Analysis by H-NMR, C-NMR, and HPLC confirmed that this white solid was a mixture of hexafluoroantimonate salts having the cation structures of (C1-1) to (C1-3), and the ratio was 99.81:0.02:0.17.

[0202] Manufacturing Example 3: Synthesis of Sulfonium Salt Mixture (PAG-3) A white solid (121 g, yield 68%) was obtained in the same manner as in Manufacturing Example 1, except that 43 g of potassium hexafluorophosphate was changed to 160 g of lithium tetrakis(pentafluorophenyl)borate. Analysis by H-NMR, C-NMR, and HPLC confirmed that this white solid was a mixture of tetrakis(pentafluorophenyl)borate salts having the cation structures of (C1-1) to (C1-3), and the ratio was 99.44:0.04:0.52.

[0203] Manufacturing Example 4: Synthesis of Sulfonium Salt Mixture (PAG-4) A white solid (94 g, yield 62%) was obtained in the same manner as in Manufacturing Example 1, except that 43 g of potassium hexafluorophosphate was changed to 101 g of potassium tris(pentafluoroethyl)trifluorophosphate. Analysis by H-NMR, C-NMR, and HPLC confirmed that this white solid was a mixture of tris(pentafluoroethyl)trifluorophosphate salts having the cation structures of (C1-1) to (C1-3), and the ratio was 99.64:0.02:0.34.

[0204] Manufacturing Example 5: Synthesis of Sulfonium Salt Mixture (PAG-5) Except that 43 g of potassium hexafluorophosphate was changed to 177 g of sodium tetrakis(pentafluorophenyl)gallate in Production Example 1, in the same manner as in Production Example 1, 113 g of a white solid (yield 55%) was obtained. By analysis using H-NMR, C-NMR, and HPLC, it was confirmed that this white solid was a mixture of each tetrakis(pentafluorophenyl)gallate salt having the cation structures of (C1-1) to (C1-3), and the ratio thereof was 99.01:0.02:0.97.

[0205] 〔Production Example 6〕Synthesis of sulfonium salt mixture (PAG-6) Except that 40 g of diphenyl sulfoxide was changed to 46 g of di-p-tolyl sulfoxide and 36 g of diphenyl sulfide was changed to 47 g of (4-tert-butylphenyl)phenyl sulfide in Production Example 1, in the same manner as in Production Example 1, 87 g of a pale yellow solid (yield 78%) was obtained. By analysis using H-NMR, C-NMR, and HPLC, it was confirmed that this pale yellow solid was a mixture of each hexafluorophosphate salt having the cation structures of (C2-1) to (C2-3), and the ratio thereof was 98.94:0.02:1.04.

[0206] 〔Production Example 7〕Synthesis of sulfonium salt mixture (PAG-7) Except that 40 g of diphenyl sulfoxide was changed to 46 g of di-p-tolyl sulfoxide, 36 g of diphenyl sulfide was changed to 47 g of (4-tert-butylphenyl)phenyl sulfide, and 43 g of potassium hexafluorophosphate was changed to 101 g of potassium tris(pentafluoroethyl)trifluorophosphate in Production Example 1, in the same manner as in Production Example 1, 80 g of a pale yellow solid (yield 48%) was obtained. By analysis using H-NMR, C-NMR, and HPLC, it was confirmed that this pale yellow solid was a mixture of each tris(pentafluoroethyl)trifluorophosphate salt having the cation structures of (C2-1) to (C2-3), and the ratio thereof was 99.14:0.02:0.83.

[0207] 〔Production Example 8〕Synthesis of sulfonium salt mixture (PAG-8) In Production Example 1, except that 40 g of diphenyl sulfoxide was changed to 46 g of di-p-tolyl sulfoxide, 36 g of diphenyl sulfide was changed to 47 g of (4-tert-butylphenyl)phenyl sulfide, and 43 g of potassium hexafluorophosphate was changed to 177 g of sodium tetrakispentafluorophenyl gallate, 89 g of a pale yellow solid (yield: 40%) was obtained in the same manner as in Production Example 1. Analysis by 1H-NMR, 13C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of each tetrakispentafluorophenyl gallate salt having a cation structure of (C2-1) to (C2-3), and the ratio thereof was 99.11:0.02:0.87.

[0208] [Production Example 9] Synthesis of Sulfonium Salt Mixture (PAG-9) In Production Example 1, except that 40 g of diphenyl sulfoxide was changed to 61 g of (3-benzoylphenyl)phenyl sulfoxide and 36 g of diphenyl sulfide was changed to 56 g of (3-benzoylphenyl)phenyl sulfide, 94 g of a yellow solid (yield: 70%) was obtained in the same manner as in Production Example 1. Analysis by 1H-NMR, 13C-NMR, and HPLC confirmed that this yellow solid was a mixture of each hexafluorophosphate salt having a cation structure of (C3-1) to (C3-3), and the ratio thereof was 99.22:0.01:0.77.

[0209] [Production Example 10] Synthesis of Sulfonium Salt Mixture (PAG-10) In Production Example 1, except that 40 g of diphenyl sulfoxide was changed to 61 g of (3-benzoylphenyl)phenyl sulfoxide, 36 g of diphenyl sulfide was changed to 56 g of (3-benzoylphenyl)phenyl sulfide, and 43 g of potassium hexafluorophosphate was changed to 160 g of lithium tetrakispentafluorophenyl borate, 119 g of a yellow solid (yield: 51%) was obtained in the same manner as in Production Example 1. Analysis by 1H-NMR, 13C-NMR, and HPLC confirmed that this yellow solid was a mixture of each tetrakispentafluorophenyl borate salt having a cation structure of (C3-1) to (C3-3), and the ratio thereof was 99.12:0.01:0.87.

[0210] [Production Example 11] Synthesis of Sulfonium Salt Mixture (PAG-11) In Production Example 1, except that 40 g of diphenyl sulfoxide was changed to 61 g of (3-benzoylphenyl)phenyl sulfoxide, 36 g of diphenyl sulfide was changed to 56 g of (3-benzoylphenyl)phenyl sulfide, and 43 g of potassium hexafluorophosphate was changed to 177 g of sodium tetrakispentafluorophenyl gallate, 137 g of a yellow solid (yield 56%) was obtained in the same manner as in Production Example 1. Analysis by H-NMR, C-NMR, and HPLC confirmed that this yellow solid was a mixture of each tetrakispentafluorophenyl gallate salt having the cation structures of (C3-1) to (C3-3), and the ratio was 98.82:0.02:1.16.

[0211] [Production Example 12] Synthesis of Sulfonium Salt Mixture (PAG-12) In Production Example 1, except that 36 g of diphenyl sulfide was changed to a solution of 41 g of thioxanthone dissolved in 100 mL of acetonitrile, 67 g of a yellow solid (yield 66%) was obtained in the same manner as in Production Example 1. Analysis by H-NMR, C-NMR, and HPLC confirmed that this yellow solid was a mixture of each hexafluorophosphate salt having the cation structures of (C9-1) to (C9-3), and the ratio was 99.71:0.03:0.26.

[0212] [Production Example 13] Synthesis of Sulfonium Salt Mixture (PAG-13) In Production Example 1, except that 36 g of diphenyl sulfide was changed to a solution of 41 g of thioxanthone dissolved in 100 mL of acetonitrile and 43 g of potassium hexafluorophosphate was changed to 55 g of potassium hexafluoroantimonate, 67 g of a yellow solid (yield 66%) was obtained in the same manner as in Production Example 1. Analysis by H-NMR, C-NMR, and HPLC confirmed that this yellow solid was a mixture of each hexafluoroantimonate salt having the cation structures of (C9-1) to (C9-3), and the ratio was 99.44:0.03:0.53.

[0213] [Production Example 14] Synthesis of Sulfonium Salt Mixture (PAG-14) In Production Example 1, except that 36 g of diphenyl sulfide was dissolved in 41 g of thioxanthone and 100 mL of acetonitrile, and 43 g of potassium hexafluorophosphate was changed to 101 g of potassium tris(pentafluoroethyl)trifluorophosphate, 111 g of a yellow solid (yield 71%) was obtained in the same manner as in Production Example 1. Analysis by H-NMR, C-NMR, and HPLC confirmed that this yellow solid was a mixture of each tris(pentafluoroethyl)trifluorophosphate having a cation structure of (C9-1) to (C9-3), and the ratio was 99.32:0.02:0.66.

[0214] [Production Example 15] Synthesis of Sulfonium Salt Mixture (PAG-15) In Production Example 1, except that 40 g of diphenyl sulfoxide was changed to 66 g of 2-phenylsulfenylanthraquinone, and 36 g of diphenyl sulfide was changed to 61 g of 2-phenylthioanthraquinone, 104 g of a yellow solid (yield 72%) was obtained in the same manner as in Production Example 1. Analysis by H-NMR, C-NMR, and HPLC confirmed that this yellow solid was a mixture of each hexafluorophosphate having a cation structure of (C10-1) to (C10-3), and the ratio was 99.23:0.01:0.67.

[0215] [Production Example 16] Synthesis of Sulfonium Salt Mixture (PAG-16) In Production Example 1, except that 40 g of diphenyl sulfoxide was changed to 61 g of 2-phenylthioanthraquinone, 36 g of diphenyl sulfide was changed to 66 g of 2-phenylsulfenylanthraquinone, and 43 g of potassium hexafluorophosphate was changed to 160 g of lithium tetrakis(pentafluorophenyl)borate, 195 g of a yellow solid (yield 80%) was obtained in the same manner as in Production Example 1. Analysis by H-NMR, C-NMR, and HPLC confirmed that this yellow solid was a mixture of each tetrakis(pentafluorophenyl)borate salt having a cation structure of (C10-1) to (C10-3), and the ratio was 99.12:0.01:0.87.

[0216] 〔Production Example 17〕Synthesis of Sulfonium Salt Mixture (PAG-17) In Production Example 1, except that 40 g of diphenyl sulfoxide was changed to 61 g of 2-phenylthioanthraquinone, 36 g of diphenyl sulfide was changed to 66 g of 2-phenylsulfenylanthraquinone, and 43 g of potassium hexafluorophosphate was changed to 177 g of sodium tetrakispentafluorophenyl gallate, a yellow solid of 195 g (yield 80%) was obtained in the same manner as in Production Example 1. Analysis by H-NMR, C-NMR, and HPLC confirmed that this yellow solid was a mixture of each tetrakispentafluorophenyl gallate salt having a cation structure of (C10-1) to (C10-3), and the ratio was 99.27:0.02:0.71.

[0217] 〔Production Example 18〕Synthesis of Sulfonium Salt Mixture (PAG-18) In Production Example 1, except that 40 g of diphenyl sulfoxide was changed to 67 g of 2-phenylsulfenylthioxanthone and 36 g of diphenyl sulfide was changed to 62 g of 2-phenylthiotioxanthone, a yellow solid of 128 g (yield 88%) was obtained in the same manner as in Production Example 1. Analysis by H-NMR, C-NMR, and HPLC confirmed that this yellow solid was a mixture of each hexafluorophosphate salt having a cation structure of (C11-1) to (C11-3), and the ratio was 98.52:0.03:1.45.

[0218] 〔Production Example 19〕Synthesis of Sulfonium Salt Mixture (PAG-19) In Production Example 1, except that 40 g of diphenyl sulfoxide was changed to 67 g of 2-phenylsulfenylthioxanthone, 36 g of diphenyl sulfide was changed to 62 g of 2-phenylthiothioxanthone, and 43 g of potassium hexafluorophosphate was changed to 160 g of lithium tetrakispentafluorophenylborate, a yellow solid (245 g, yield: 88%) was obtained in the same manner as in Production Example 1. Analysis by H-NMR, C-NMR, and HPLC confirmed that this yellow solid was a mixture of each tetrakispentafluorophenylborate salt having the cation structures of (C11-1) to (C11-3), and the ratio thereof was 98.11:0.04:1.85.

[0219] 〔Production Example 20〕Synthesis of sulfonium salt mixture (PAG-20) In Production Example 1, except that 40 g of diphenyl sulfoxide was changed to 67 g of 2-phenylsulfenylthioxanthone, 36 g of diphenyl sulfide was changed to 62 g of 2-phenylthiothioxanthone, and 43 g of potassium hexafluorophosphate was changed to 101 g of potassium tris(pentafluoroethyl)trifluorophosphate, a yellow solid (133 g, yield: 66%) was obtained in the same manner as in Production Example 1. Analysis by H-NMR, C-NMR, and HPLC confirmed that this yellow solid was a mixture of each tris(pentafluoroethyl)trifluorophosphate salt having the cation structures of (C11-1) to (C11-3), and the ratio thereof was 98.85:0.03:1.12.

[0220] 〔Production Example 21〕Synthesis of sulfonium salt mixture (PAG-21) 7.9 g of diphenyl sulfoxide, 8.9 g of 4-(phenylthio)acetophenone, and 22 g of acetic anhydride were dissolved therein. 16 parts of methanesulfonic acid was added dropwise thereto so as not to exceed 40°C, and the mixture was further reacted at 65°C for 3 hours. The reaction solution was cooled to room temperature, poured into 100 mL of ion-exchanged water, extracted with 100 g of dichloromethane, and washed with water until the pH of the aqueous layer became neutral. The dichloromethane layer was transferred to a rotary evaporator to distill off the solvent, whereby a brown solid was obtained. This was washed with ethyl acetate / hexane, and the organic solvent was concentrated to obtain (Intermediate-1). (Intermediate-1) 5.1 g was dissolved in 60 mL of dichloromethane, and 50 g of an aqueous solution of sodium hexafluorophosphate in an equimolar amount was mixed at room temperature. The mixture was stirred as it was for 3 hours, and the dichloromethane layer was washed 5 times with water by liquid separation operation. Then, it was transferred to a rotary evaporator to distill off the solvent, and 4.9 g of a pale yellow solid was obtained (yield 88%). Analysis by H-NMR, C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of hexafluorophosphate salts each having a cation structure of (C4-1) to (C4-3), and the ratio was 99.17:0.02:0.81.

[0221] 〔Production Example 22〕Synthesis of sulfonium salt mixture (PAG-22) In Production Example 21, except that 50 g of the aqueous solution of sodium hexafluorophosphate was changed to 100 g of an aqueous solution of lithium tetrakis(pentafluorophenyl)borate, 8.5 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield 78%). Analysis by H-NMR, C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of tetrakis(pentafluorophenyl)borate salts each having a cation structure of (C4-1) to (C4-3), and the ratio was 99.07:0.02:0.91.

[0222] 〔Production Example 23〕Synthesis of sulfonium salt mixture (PAG-23) In Production Example 21, except that 50 g of the aqueous solution of sodium hexafluorophosphate was changed to 50 g of an aqueous solution of potassium trifluoromethanesulfonate, 4.5 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield 80%). Analysis by H-NMR, C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of trifluoromethanesulfonate salts each having a cation structure of (C4-1) to (C4-3), and the ratio was 99.23:0.03:0.74.

[0223] 〔Production Example 24〕Synthesis of sulfonium salt mixture (PAG-24) In Production Example 21, 50 g of an aqueous sodium hexafluorophosphate solution was changed to 50 g of an aqueous potassium tris(pentafluoroethyl)trifluorophosphate solution, and 7.6 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield 89%). Analysis by 1H-NMR, 13C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of tris(pentafluoroethyl)trifluorophosphates having the cationic structures of (C4-1) to (C4-3), and the ratio thereof was 99.19:0.02:0.79.

[0224] 〔Production Example 25〕Synthesis of sulfonium salt mixture (PAG-25) In Production Example 21, 7.9 g of diphenyl sulfoxide was changed to 11 g of 4-[(phenyl)sulfinyl]biphenyl, and 8.9 g of 4-(phenylthio)acetophenone was changed to 12 g of 4-(phenylthio)biphenyl, and 5.5 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield 82%). Analysis by 1H-NMR, 13C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of hexafluorophosphates having the cationic structures of (C5-1) to (C5-3), and the ratio thereof was 98.32:0.03:1.65.

[0225] 〔Production Example 26〕Synthesis of sulfonium salt mixture (PAG-26) In Production Example 21, 7.9 g of diphenyl sulfoxide was changed to 11 g of 4-[(phenyl)sulfinyl]biphenyl, 8.9 g of 4-(phenylthio)acetophenone was changed to 12 g of 4-(phenylthio)biphenyl, and 50 g of an aqueous sodium hexafluorophosphate solution was changed to 50 g of an aqueous potassium tris(pentafluoroethyl)trifluorophosphate solution, and 7.8 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield 81%). Analysis by 1H-NMR, 13C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of tris(pentafluoroethyl)trifluorophosphates having the cationic structures of (C5-1) to (C5-3), and the ratio thereof was 99.86:0.04:0.10.

[0226] 〔Production Example 27〕Synthesis of sulfonium salt mixture (PAG-27) In Production Example 21, except that 7.9 g of diphenyl sulfoxide was changed to 11 g of 4-[(phenyl)sulfinyl]biphenyl, 8.9 g of 4-(phenylthio)acetophenone was changed to 12 g of 4-(phenylthio)biphenyl, and 50 g of an aqueous sodium hexafluorophosphate solution was changed to 50 g of an aqueous potassium trifluoromethanesulfonate solution, 5.1 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield 70%). Analysis by H-NMR, C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of trifluoromethanesulfonates each having a cation structure of (C5-1) to (C5-3), and the ratio thereof was 98.08:0.03:1.89.

[0227] 〔Production Example 28〕Synthesis of sulfonium salt mixture (PAG-28) In Production Example 21, except that 7.9 g of diphenyl sulfoxide was changed to 11 g of 3-[(phenyl)sulfinyl]biphenyl and 8.9 g of 4-(phenylthio)acetophenone was changed to 12 g of 4-(phenylthio)biphenyl, 5.6 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield 84%). Analysis by H-NMR, C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of hexafluorophosphate salts each having a cation structure of (C6-1) to (C6-3), and the ratio thereof was 99.44:0.01:0.55.

[0228] 〔Production Example 29〕Synthesis of sulfonium salt mixture (PAG-29) In Production Example 21, except that 7.9 g of diphenyl sulfoxide was changed to 11 g of 3-[(phenyl)sulfinyl]biphenyl, 8.9 g of 4-(phenylthio)acetophenone was changed to 12 g of 4-(phenylthio)biphenyl, and 50 g of an aqueous sodium hexafluorophosphate solution was changed to 50 g of an aqueous potassium tris(pentafluoroethyl)trifluorophosphate solution, 8.2 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield 85%). Analysis by H-NMR, C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of each tris(pentafluoroethyl)trifluorophosphate having the cation structures of (C6-1) to (C6-3), and the ratio was 99.51:0.01:0.48.

[0229] 〔Production Example 30〕Synthesis of sulfonium salt mixture (PAG-30) In Production Example 21, except that 7.9 g of diphenyl sulfoxide was changed to 11 g of 3-[(phenyl)sulfinyl]biphenyl, 8.9 g of 4-(phenylthio)acetophenone was changed to 12 g of 4-(phenylthio)biphenyl, and 50 g of an aqueous sodium hexafluorophosphate solution was changed to 50 g of an aqueous potassium trifluoromethanesulfonate solution, 5.3 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield 79%). Analysis by H-NMR, C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of each trifluoromethanesulfonate having the cation structures of (C6-1) and (C6-3), and the ratio was 99.74:0.26.

[0230] 〔Production Example 31〕Synthesis of sulfonium salt mixture (PAG-31) In Production Example 21, except that 7.9 g of diphenyl sulfoxide was changed to 12 g of 4-[(2-methoxyphenyl)sulfinyl]biphenyl and 8.9 g of 4-(phenylthio)acetophenone was changed to 11 g of 4-(2-methoxyphenylthio)biphenyl, 6.4 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield 88%). Analysis by H-NMR, C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of hexafluorophosphate salts each having a cation structure of (C7-1) to (C7-3), and the ratio thereof was 98.89:0.03:1.08.

[0231] Production Example 32: Synthesis of Sulfonium Salt Mixture (PAG-32) In Production Example 21, except that 7.9 g of diphenyl sulfoxide was changed to 12 g of 4-[(2-methoxyphenyl)sulfinyl]biphenyl, 8.9 g of 4-(phenylthio)acetophenone was changed to 11 g of 4-(2-methoxyphenylthio)biphenyl, and 50 g of an aqueous sodium hexafluorophosphate solution was changed to 50 g of an aqueous potassium tris(pentafluoroethyl)trifluorophosphate solution, 7.7 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield 75%). Analysis by H-NMR, C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of tris(pentafluoroethyl)trifluorophosphate salts each having a cation structure of (C7-1) to (C7-3), and the ratio thereof was 98.88:0.03:1.09.

[0232] Production Example 33: Synthesis of Sulfonium Salt Mixture (PAG-33) In Production Example 21, except that 7.9 g of diphenyl sulfoxide was changed to 12 g of (4 - phenoxyphenyl)phenyl sulfoxide, 8.9 g of 4 - (phenylthio)acetophenone was changed to 11 g of (4 - phenoxyphenyl)phenyl sulfide, and 50 g of an aqueous sodium hexafluorophosphate solution was changed to 50 g of an aqueous potassium trifluoromethanesulfonate solution, 6.1 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield 83%). Analysis by H - NMR, C - NMR, and HPLC confirmed that this pale yellow solid was a mixture of each trifluoromethanesulfonate having the cation structures of (C7 - 1) to (C7 - 3), and the ratio was 98.67:0.03:1.30.

[0233] 〔Production Example 34〕Synthesis of sulfonium salt mixture (PAG - 34) In Production Example 21, except that 7.9 g of diphenyl sulfoxide was changed to 12 g of (4 - phenoxyphenyl)phenyl sulfoxide, 8.9 g of 4 - (phenylthio)acetophenone was changed to 11 g of (4 - phenoxyphenyl)phenyl sulfide, 4.8 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield 69%). Analysis by H - NMR, C - NMR, and HPLC confirmed that this pale yellow solid was a mixture of each hexafluorophosphate having the cation structures of (C8 - 1) to (C8 - 3), and the ratio was 99.25:0.02:0.73.

[0234] 〔Production Example 35〕Synthesis of sulfonium salt mixture (PAG - 35) In Production Example 21, except that 7.9 g of diphenyl sulfoxide was changed to 12 g of (4-phenoxyphenyl)phenyl sulfoxide, 8.9 g of 4-(phenylthio)acetophenone was changed to 11 g of (4-phenoxyphenyl)phenyl sulfide, and 50 g of an aqueous sodium hexafluorophosphate solution was changed to 50 g of an aqueous potassium trifluoromethanesulfonate solution, 5.4 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield: 77%). Analysis by H-NMR, C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of each trifluoromethanesulfonate having the cationic structures of (C8-1) to (C8-3), and the ratio thereof was 99.21:0.02:0.77.

[0235] 〔Production Example 36〕Synthesis of Sulfonium Salt Mixture (PAG-36) In Production Example 21, except that 7.9 g of diphenyl sulfoxide was changed to 12 g of (4-phenoxyphenyl)phenyl sulfoxide, 8.9 g of 4-(phenylthio)acetophenone was changed to 11 g of (4-phenoxyphenyl)phenyl sulfide, and 50 g of an aqueous sodium hexafluorophosphate solution was changed to 100 g of an aqueous lithium tetrakispentafluorophenylborate solution, 10 g of a pale yellow solid was obtained in the same manner as in Production Example 21 (yield: 81%). Analysis by H-NMR, C-NMR, and HPLC confirmed that this pale yellow solid was a mixture of each tetrakispentafluorophenylborate salt having the cationic structures of (C8-1) to (C8-3), and the ratio thereof was 99.33:0.03:0.64.

[0236] 〔Production Example 37〕Synthesis of Sulfonium Salt Mixture (PAG-37) In Production Example 21, except that 7.9 g of diphenyl sulfoxide was changed to 13 g of 2-phenylsulfenylthianthrene and 8.9 g of 4-(phenylthio)acetophenone was changed to 13 g of 2-phenylthiothianthrene, 4.4 g of a yellow solid was obtained in the same manner as in Production Example 21 (yield 55%). Analysis by H-NMR, C-NMR, and HPLC confirmed that this yellow solid was a mixture of hexafluorophosphate salts each having a cation structure of (C12-1) to (C12-3), and the ratio was 99.62:0.01:0.37.

[0237] 〔Production Example 38〕Synthesis of sulfonium salt mixture (PAG-38) In Production Example 21, except that 7.9 g of diphenyl sulfoxide was changed to 13 g of 2-phenylsulfenylthianthrene, 8.9 g of 4-(phenylthio)acetophenone was changed to 13 g of 2-phenylthiothianthrene, and 50 g of an aqueous sodium hexafluorophosphate solution was changed to 50 g of an aqueous potassium trifluoromethanesulfonate solution, 6.2 g of a yellow solid was obtained in the same manner as in Production Example 21 (yield 55%). Analysis by H-NMR, C-NMR, and HPLC confirmed that this yellow solid was a mixture of trifluoromethanesulfonate salts each having a cation structure of (C12-1) and (C12-3), and the ratio was 99.67:0.33.

[0238] 〔Production Example 39〕Synthesis of sulfonium salt mixture (PAG-39) In Production Example 21, except that 7.9 g of diphenyl sulfoxide was changed to 13 g of 2-phenylsulfenylthianthrene, 8.9 g of 4-(phenylthio)acetophenone was changed to 13 g of 2-phenylthiothianthrene, and 50 g of an aqueous sodium hexafluorophosphate solution was changed to 100 g of an aqueous lithium tetrakispentafluorophenylborate solution, 11 g of a yellow solid was obtained in the same manner as in Production Example 21 (yield 83%). Analysis by H-NMR, C-NMR, and HPLC confirmed that this yellow solid was a mixture of tetrakispentafluorophenylborate salts each having a cation structure of (C12-1) to (C12-3), and the ratio was 99.68:0.01:0.31.

[0239] 〔Reference Production Example 1〕(PAG H-1 to H-12) The white solid obtained in Production Example 1 was repeatedly recrystallized with dichloromethane / methanol to obtain a hexafluorophosphate (PAG H-1) consisting essentially of only cation C1-1 (Cation C1-2 and C1-3 were below the detection limit (0.005% or less) by HPLC). Similarly, the solids obtained in Production Examples 6, 9, 12, 15, 18, 23, 27, 30, 33, 35, and 38 for PAG H-2 to H-12 were each purified by recrystallization. The compositions are as shown in Table 1 for PAG H-1 to H-6, and in Tables 2 and 3 for PAG H-7 to H12.

[0240] 〔Reference Production Example 2〕(PAG-40 to 41, PAG H-13) In Production Example 1, the washing liquid after washing with methanol and hexane was collected and concentrated with an evaporator, and the resulting solid was purified with chloroform / hexane to obtain a light brown solid. It was found by HPLC that this solid was a mixture of sulfonium salts C1-2 and C1-3. By adding an appropriate amount of this to PAG H-1 obtained in Reference Production Example 1, PAG-40 to 41 and PAG H-13 were obtained. Composition analysis was performed by HPLC for each. The compositions are as shown in Table 1.

[0241] 〔Reference Production Example 3〕(PAG-42 to 47, PAG H-14 to H18) In the same manner as in Reference Production Example 2, a mixture of sulfonium salts obtained by purifying the solids recovered from the washing liquid in Production Examples 6, 9, 12, 15, and 18 for PAG-42 to 47 and PAG H-14 to 18, respectively, was added in an appropriate amount to the corresponding PAG H-2 to H-6 obtained in Reference Production Example 1 to obtain PAG-42 to 47 and PAG H-14 to 18. Composition analysis was performed by HPLC for each. The compositions are as shown in Table 1.

[0242] 〔Reference Production Example 4〕(PAG-48 to 54, PAG H-19 to H24) In the same manner as in Reference Production Example 2, the sulfonium salt mixtures obtained by purifying the solids recovered from the cleaning liquid in Production Examples 23, 27, 30, 33, 35, and 38 for PAG-48 to 54 and PAG H-19 to 24, respectively, were added in appropriate amounts to PAG H-7 to H-12 obtained in the corresponding Reference Production Example 1 to obtain PAG-48 to 54 and PAG H-19 to 24. The composition analysis was performed by HPLC for each. The composition is as described in Tables 3 and 5.

[0243] <Preparation and Evaluation of Photocurable Composition> The above photoacid generator was previously dissolved in propylene carbonate (Solvent-1) to a concentration of 50% by weight, and uniformly mixed with the epoxy resin (described below), which is a cationic polymerizable compound, in the blending amounts shown in Table 1 to prepare photocurable compositions (Examples 1 to 40 and Comparative Examples 1 to 12). Each of these compositions was placed in a light-shielding bottle, stored at a predetermined temperature for a predetermined period (the following storage conditions), and the appearance and photocurability (cationic polymerization performance) were evaluated by the following methods and compared with those immediately after blending. The results are shown in Table 2. <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

[0244]

Table 1

[0245] <Storage Conditions> Storage Condition-1: 20°C × 3 months Storage Condition-2: 0°C × 3 months Storage Condition-3: -10°C × 3 months

[0246] <Appearance Evaluation> A part of the above composition was taken out from a light-shielding bottle, and the transparency and presence or absence of precipitation of the composition were evaluated. (Evaluation Criteria) ◎: The composition is transparent. △: Cloudiness was observed in the composition. ×: Precipitation and sedimentation were observed. (Evaluation of Photo-curing Property (Cationic Polymerization Performance)) The above composition was applied onto a polyethylene terephthalate (PET) film with a film thickness of 25 μm using an applicator. After the above application, the PET film was irradiated with light whose wavelength was limited by a filter using an ultraviolet irradiation device. Note that an IRCF02 filter (manufactured by Aigraphics Co., Ltd., a filter that cuts light with a wavelength of less than 340 nm) was used as the filter. After irradiation, the hardness of the coating film after 40 minutes was measured by pencil hardness (JIS K5600-5-4:1999), and the results evaluated according to the following criteria are shown in Table 2. The higher the pencil hardness, the better the sensitivity (cationic polymerization curability) of the photo-curing composition.

[0247] (Evaluation Criteria) ◎: Pencil hardness is 2H or higher ○: Pencil hardness is H to B △: Pencil hardness is 2B to 4B ×: Liquid to tacky, and pencil hardness cannot be measured

[0248] (Light Irradiation Conditions) · Ultraviolet irradiation device: Belt conveyor type UV irradiation device (manufactured by Aigraphics Co., Ltd.) · Lamp: 1.5 kW high-pressure mercury lamp · Filter: IRCF02 filter (manufactured by Aigraphics Co., Ltd.) · Illuminance (measured with a 365 nm head illuminance meter): 150 mW / cm 2 · Integrated light quantity (measured with a 365 nm head illuminance meter): 200 mJ / cm 2

[0249]

Table 2

[0250] As shown in Table 2, it can be seen that the compositions containing the photoacid generator of the present invention from Examples 1 to 40 and Comparative Examples 1 to 12 have excellent low-temperature storage stability. Also, from Comparative Examples 1 to 6, it can be seen that although the structure of formula (1) alone has excellent photocurability, its low-temperature storage stability is rather decreased. Further, as can be seen from Examples 21 to 28 and Comparative Examples 7 to 12, since the structures of formula (2) and formula (3) cause a decrease in photocurability when contained in a certain ratio or more, it can be seen that the total content of the structure of formula (2) and the structure of formula (3) needs to be 5.5% or less. Also, as shown by Examples 1 to 20 and Examples 29 to 40, it can be seen that the compositions containing the photoacid generator of the present invention have excellent low-temperature storage stability regardless of the type of anion structure or epoxy resin.

[0251] <Evaluation of Positive Photoresist Composition> (Preparation of Samples for Evaluation) As shown in Table 3, 1 to 1.5 parts of a photoacid generator, 40 parts of a resin represented by the following chemical formula (Resin-1) as the 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 the resin component (C) were uniformly dissolved in 150 parts of 2-methoxy-1-methylethyl acetate (Solvent-2), filtered through a membrane filter with a pore size of 1 μm, and a positive photoresist composition (Examples 41 to 66) with a solid content concentration of 40% by weight was prepared. For the comparative examples, the same procedure as the above examples was carried out to prepare positive photoresist compositions (Comparative Examples 13 to 24). These compositions were stored at a predetermined temperature for a predetermined period, and the positive photoresist compositions were evaluated by the following method and compared with those immediately after blending. The results are shown in Table 4.

[0252]

Table 3

[0253] <Sensitivity Evaluation> After spin-coating the positive resist composition on a silicon wafer substrate and drying it, a photoresist layer having a film thickness of about 20 μm was obtained. This resist layer was prebaked at 130 °C for 6 minutes using a hot plate. After prebaking, pattern exposure (i-line) was performed using TME-150RSC (manufactured by Topcon Corporation), and post-exposure baking (PEB) was performed at 75 °C for 5 minutes using a hot plate. Then, development treatment was carried out for 5 minutes by an immersion method using a 2.38 wt% aqueous solution of tetramethylammonium hydroxide, followed by washing with running water and blowing with nitrogen to obtain a 10-μm line and space (L&S) pattern. Furthermore, the minimum exposure amount at which no residue of this pattern was observed below that, that is, the minimum essential exposure amount required to form a resist pattern (corresponding to sensitivity) was measured.

[0254] <Pattern Shape Evaluation> By the above operation, the dimension La of the lower side and the dimension Lb of the upper side of the cross-section of the shape of the 10-μm L&S pattern formed on the silicon wafer substrate were measured using a scanning electron microscope, and the pattern shape was judged according to the following criteria. ◎: 0.90 ≦ Lb / La ≦ 1 ○: 0.85 ≦ Lb / La < 0.90 ×: Lb / La < 0.85

[0255]

Table 4

[0256]

Chemical Formula

[0257] As shown in Table 4, it can be seen that the chemically amplified positive photoresist composition containing the photoacid generator of the present invention has excellent low-temperature storage stability from Examples 41 to 66 and Comparative Examples 13 to 24. From Comparative Examples 13 to 18, it can be seen that although only the structure of formula (1) has excellent resist performance, the low-temperature storage stability is reduced. Further, as can be seen from Examples 60 to 66 and Comparative Examples 19 to 24, since the structures of formula (2) and formula (3) cause a decrease in resist performance when contained in a certain ratio or more, it can be seen that the total content of the structure of formula (2) and the structure of formula (3) needs to be 5.5% or less. Also, as shown in Examples 41 to 59, it can be seen that the composition containing the photoacid generator of the present invention has excellent low-temperature storage stability regardless of the anion structure.

[0258] <Preparation and Evaluation of Negative Photoresist Composition> (Preparation of Evaluation Samples) As shown in Table 5, 1 part of a photoacid generator, 100 parts of a copolymer (Mw = 10,000) composed of p-hydroxystyrene / styrene = 80 / 20 (molar ratio) as component (F) which is a phenol resin, 20 parts of hexamethoxymethylmelamine (manufactured by Sanwa Chemical Co., Ltd., trade name "Niclac MW-390") as component (G) which is a crosslinking agent, 10 parts of a copolymer composed of butadiene / acrylonitrile / hydroxybutyl methacrylate / methacrylic acid / divinylbenzene = 64 / 20 / 8 / 6 / 2 (weight%) (average particle size = 65 nm, Tg = -38 °C) as component (H) which is crosslinked fine particles, and 5 parts of γ-glycidoxypropyltrimethoxysilane (manufactured by Chisso Corporation, trade name "S510") as component (J) which is an adhesion aid were uniformly dissolved in 145 parts of ethyl lactate (solvent-3) to prepare the negative photoresist composition of the present invention (Examples 67 to 92, Comparative Examples 25 to 36). Further, the negative photoresist composition was evaluated by the following method. The results are shown in Table 6.

[0259]

Table 5

[0260] <Sensitivity Evaluation> After spin-coating each composition on a silicon wafer substrate, it was heated and dried at 110 °C for 3 minutes using a hot plate to obtain a resin coating film having a film thickness of about 20 μm. Then, pattern exposure (i-line) was performed using TME-150RSC (manufactured by Topcon Corporation), and post-exposure baking (PEB) was performed at 110 °C for 3 minutes using a hot plate. Then, development treatment was performed for 2 minutes by an immersion method using a 2.38 wt% aqueous solution of tetramethylammonium hydroxide, washed with running water, and blown with nitrogen to obtain a 10-μm line-and-space pattern. Furthermore, the minimum necessary exposure amount (corresponding to sensitivity) required to form a pattern with a remaining film ratio of 95% or more indicating the ratio of the remaining film before and after development was measured.

[0261] <Pattern shape evaluation> By the above operation, the dimension La of the lower side and the dimension Lb of the upper side of the cross-section of the shape of the 20-μm L&S pattern formed on the silicon wafer substrate were measured using a scanning electron microscope, and the pattern shape was judged according to the following criteria. ◎: 0.90 ≤ La / Lb ≤ 1 ○: 0.85 ≤ La / Lb < 0.90 ×: La / Lb < 0.85

[0262]

Table 6

[0263] As shown in Table 6, it can be seen that the low-temperature storage stability of the chemically amplified negative photoresist composition containing the photoacid generator of the present invention is excellent from Examples 67 to 92 and Comparative Examples 25 to 36. From Comparative Examples 25 to 30, it can be seen that although the resist performance is excellent only with the structure of formula (1), the low-temperature storage stability is deteriorated. Also, as can be seen from Examples 86 to 92 and Comparative Examples 31 to 36, since the structures of formula (2) and formula (3) cause a decrease in resist performance when contained in a certain ratio or more, it can be seen that the total content of the structures of formula (2) and formula (3) needs to be 5.5% or less. Also, as shown in Examples 67 to 85, it can be seen that the low-temperature storage stability of the composition containing the photoacid generator of the present invention is excellent regardless of the anion structure.

Industrial Applicability

[0264] The photoacid generator of the present invention is used in photoactive energy ray-curable compositions such as paints, coating agents, various coating materials (hard coats, stain-resistant coatings, anti-fog coatings, corrosion-resistant coatings, optical fibers, etc.), backside treatment agents for adhesive tapes, release coating materials for release sheets for adhesive labels (release papers, release plastic films, release metal foils, etc.), printing plates, dental materials (dental formulations, dental composites), inks, inkjet inks, positive resists (for forming connection terminals and wiring patterns in the manufacture of electronic components such as circuit boards, CSPs, MEMS elements, etc.), resist films, liquid resists, negative resists (permanent film materials such as surface protection films, interlayer insulating films, planarization films for semiconductor elements, etc.), resists for MEMS, positive 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 (deflection plates, antireflection films, etc.) for FPDs, etc.), holographic resins, FPD materials (color filters, black matrices, partition materials, photo spacers, ribs, alignment films for liquid crystals, sealants for FPDs, etc.), optical members, molding materials (for building materials, optical components, lenses), casting materials, putties, glass fiber impregnants, caulking materials, sealing materials, encapsulants for optical semiconductors (LEDs), optical waveguide materials, nanoimprint materials, materials for optical lithography, and materials for micro-optical lithography, etc.

Claims

1. A photoacid generator containing a sulfonium salt represented by the following general formulas (1) to (3), wherein when the total area of (1) to (3) is taken as 100 as measured by high performance liquid chromatography (HPLC), the total area ratio of (2) and (3) is 0.02 or more and 5.5 or less. 【Chemical 1】 [In formulas (1) to (3), R １ to R ４ are organic groups bonded to the benzene ring, m, n, p, and q each represent the number of R １ to R ４ , n is an integer from 0 to 4, m, p, and q are integers from 0 to 5. When it is 0, a hydrogen atom is bonded. When m, n, p, and q are 2 or more, they may be the same as or different from each other. Also, R １ to R ４ may form a ring structure directly or via -O-, -S-, -SO-, -SO ２ -, -NH-, -CO-, -COO-, -CONH-, an alkylene group or a phenylene group. X is an atom (group) that can become a monovalent anion.]

2. 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, methanesulfonate anion, butanesulfonate anion, camphorsulfonate anion, benzenesulfonate anion, p - toluenesulfonate anion, (CF ３ SO ２ ) ３ C － , and (CF ３ SO ２ ) ２ N － The photoacid generator according to claim 1, which is selected from the group consisting of anions represented by

3. A photocurable composition comprising the photoacid generator according to Claim 1 or 2 and a cationically polymerizable compound.

4. A cured body obtained by curing the photocurable composition according to Claim 3.

5. A chemically amplified positive photoresist composition comprising component (A) containing the photoacid generator according to Claim 1 or 2 and component (B) which is a resin whose solubility in alkali increases by the action of an acid.

6. The chemically amplified positive photoresist composition according to Claim 5, wherein 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 or 6, further comprising an alkali-soluble resin (C) and an acid diffusion control agent (D).

8. A chemically amplified negative photoresist composition comprising component (E) containing the photoacid generator according to Claim 1 or 2, component (F) which is an alkali-soluble resin having a phenolic hydroxyl group, and a crosslinking agent component (G).

9. The chemically amplified negative photoresist composition according to Claim 8, further comprising a crosslinked fine particle component (H).

10. A cured body obtained by curing the chemically amplified negative photoresist composition according to Claim 8 or 9.

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