Composition and method for manufacturing device using same

Abstract

An onium salt and a composition having high sensitivity and excellent pattern characteristics such as LWR, which is preferably used for a resist composition for a lithography process using two active energy rays of a first active energy ray such as an electron beam or an extreme ultraviolet and a second active energy ray such as UV.

Claims

1. An onium salt represented by any one selected from a following general formula (1), a following general formula (2), a following general formula (11), and a following general formula (12), ##STR00137## wherein: in the general formula (1), each of R.sup.11 and R.sup.12 is any one independently selected from the group consisting of: a linear, branched or cyclic alkyl group which may have a substituent (A), the alkyl group having 1 to 12 carbon atoms; a linear, branched or cyclic alkenyl group which may have the substituent (A), the alkenyl group having 1 to 12 carbon atoms; an aryl group which may have a substituent (B), the aryl group having 6 to 10 carbon atoms; and a heteroaryl group which may have the substituent (A), the heteroaryl group having 4 to 12 carbon atoms; a number of carbon atoms of each of the alkyl group, the alkenyl group and the heteroaryl group does not include a number of carbon atoms of the substituent (A); a number of carbon atoms of the aryl group does not include a number of carbon atoms of the substituent (B); when the aryl group of R.sup.11 and R.sup.12 may have the substituent (B), the substituent (B) is selected from the group consisting of a hydroxy group, a cyano group, a mercapto group, a carboxy group, a carbonyl group, an alkoxy group (—OR), an acyl group (—COR), an alkoxycarbonyl group (—COOR), an amino group, an alkylamino group (—NHR), a dialkylamino group (—N(R).sub.2), a phosphino group, a silyl group, a halogen atom, a trialkylsilyl group (—Si—(R).sub.3); and a main chain of a polymer; the R in the substituent (B) is the alkyl group having 1 to 20 carbon atoms; when the alkyl group, the alkenyl group and the heteroaryl group may have the substituent (A), the substituent (A) is selected from the group consisting of group (—OR), an acyl group (—COR), an alkoxycarbonyl group (—COOR), an aryl group (—Ar), an aryloxy group (—OAr), an amino group, an alkylamino group (—NHR), a dialkylamino group (—N(R).sub.2), an arylamino group (—NHAr), a diarylamino group (—N(Ar).sub.2), an N-alkyl-N-arylamino group (—NRAr), a phosphino group, a silyl group, a halogen atom, a trialkylsilyl group (—Si—(R).sub.3), a silyl group substituting at least one alkyl group of the trialkylsilyl group with Ar, an alkylsulfanyl group (—SR), an arylsulfanyl group (—SAr) and a main chain of a polymer; the R in the substituent (A) is the alkyl group having 1 to 20 carbon atoms; the Ar in the substituent (A) is the aryl group having 1 to 20 carbon atoms; any two or more of R.sup.11, R.sup.12 and an aryl group bonded to a sulfonium group may be bonded each other directly with a single bond, or through any one selected from the group consisting of: an oxygen atom; a sulfur atom; a nitrogen atom-containing group; and a methylene group to form a ring structure with a sulfur atom bonded to R.sup.11, R.sup.12 and the aryl group bonded to the sulfonium group are bonded; at least one methylene group in R.sup.11 and R.sup.12 may be substituted with a divalent hetero atom-containing group; each of R.sup.13 and R.sup.14 is any one independently selected from the group consisting of: an alkyl group; a hydroxy group; a mercapto group; an alkoxy group; an alkylcarbonyl group; an arylcarbonyl group; an alkoxycarbonyl group; an aryloxycarbonyl group; an arylsulfanylcarbonyl group; an arylsulfanyl group; an alkylsulfanyl group; an aryl group; a heteroaryl group; an aryloxy group; an alkylsulfinyl group; an arylsulfinyl group; an alkylsulfonyl group; an arylsulfonyl group; a (meth)acryloyloxy group; a hydroxy(poly)alkyleneoxy group; an amino group; a cyano group; a nitro group; and a halogen atom, where R.sup.13 and R.sup.14 have 1 to 12 carbon atoms when R.sup.13 and R.sup.14 have a carbon atom, and these groups may have the substituent (A); the substituent (A) of R.sup.13 and R.sup.14 is the same as the substituent (A) of R.sup.11 and R.sup.12, each of R.sup.15 and R.sup.16 is any one independently selected from the group consisting of: a linear, branched or cyclic alkyl group which may have the substituent (A), the alkyl group having 1 to 12 carbon atoms; a linear, branched or cyclic alkenyl group which may have the substituent (A), the alkenyl group having 1 to 12 carbon atoms; an aryl group which may have the substituent (A), the aryl group having 6 to 14 carbon atoms; and a heteroaryl group which may have the substituent (A), the heteroaryl group having 4 to 12 carbon atoms; R.sup.15 and R.sup.16 may be bonded each other directly with a single bond or through any one selected from the group consisting of: an oxygen atom; a sulfur atom; and an alkylene group to form a ring structure; at least one methylene group in R.sup.15 and R.sup.16 may be substituted with a divalent hetero atom-containing group; the substituent (A) of R.sup.15 and R.sup.16 is the same as the substituent (A) of R.sup.11 and R.sup.12, L.sup.2 is any one selected from the group consisting of: a direct bond; a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms; an alkenylene group having 1 to 12 carbon atoms; an arylene group having 6 to 14 carbon atoms; a heteroarylene group having 4 to 12 carbon atoms; and a group in which these groups are bonded through an oxygen atom, a sulfur atom or a nitrogen atom-containing group; L.sup.3 is selected from the group consisting of: a direct bond; a methylene group; a sulfur atom; a nitrogen atom-containing group; and an oxygen atom; Y is an oxygen atom or a sulfur atom; each of h and i is independently an integer of 1 to 3; j is an integer of 0 to 4 when his 1, 0 to 6 when h is 2, and 0 to 8 when his 3; k is an integer of 0 to 5 when i is 1, 0 to 7 when i is 2, and 0 to 9 when i is 3; X.sup.− is a monovalent counter anion; in the general formula (2), each of R.sup.13 to R.sup.16, L.sup.2, L.sup.3, Y, h to k and X.sup.− is independently selected from a same option as each of R.sup.13 to R.sup.16, L.sup.2, L.sup.3, Y, h to k and X.sup.− in the formula (1); R.sup.17 is any one selected from the group consisting of: an aryl group which may have the substituent (A); and a heteroaryl group which may have the substituent (A); and R.sup.17 and an aryl group bonded to an iodonium group may be bonded each other to form a ring structure with an iodine atom bonded to R.sup.17 and the aryl group bonded to the iodonium group; in the general formula (11), each of R.sup.11 to R.sup.16, L.sup.2, Y, h to k and X.sup.− is independently selected from a same option as each of R.sup.11 to R.sup.16, L.sup.2, Y, h to k and X.sup.− in the formula (1); and each of L.sup.4 and L.sup.5 is any one independently selected from the group consisting of: a direct bond; an alkenylene group having 2 carbon atoms; an alkynylene group having 2 carbon atoms; and a carbonyl group; in the general formula (12), each of R.sup.13 to R.sup.17, L.sup.2, Y, h to k and X.sup.− is independently selected from a same option as each of R.sup.13 to R.sup.17, L.sup.2, Y, h to k and X.sup.− in the formula (2); and each of L.sup.4 and L.sup.5 is any one independently selected from the group consisting of: a direct bond; an alkenylene group having 2 carbon atoms; an alkynylene group having 2 carbon atoms; and a carbonyl group.

2. The onium salt of claim 1, wherein the onium salt is represented by any one selected from the general formula (11) and the general formula (12).

3. The onium salt of claim 1, wherein the onium salt is represented by a following general formula (6), ##STR00138## where: in the general formula (6), each of R.sup.11 to R.sup.16, X.sup.− and Y is independently selected from a same option as each of R.sup.11 to R.sup.16, X.sup.− and Y in the general formula (1); R.sup.18 is any one selected from the group consisting of: an alkyl group; a hydroxy group; a mercapto group; an alkoxy group; an alkylcarbonyl group; an arylcarbonyl group; an alkoxycarbonyl group; an aryloxycarbonyl group; an arylsulfanylcarbonyl group; an arylsulfanyl group; an alkylsulfanyl group; an aryl group; a heteroaryl group; an aryloxy group; an alkylsulfinyl group; an arylsulfinyl group; an alkylsulfonyl group; an arylsulfonyl group; a (meth)acryloyloxy group; a hydroxy(poly)alkyleneoxy group; an amino group; a cyano group; a nitro group; and a halogen atom, where R.sup.18 has 1 to 12 carbon atoms when R.sup.18 has a carbon atom; e is an integer of 0 to 4; f is an integer of 0 to 4; and g is an integer of 0 to 5.

4. A photoacid generator comprising at least the onium salt of claim 1.

5. A composition comprising: the photoacid generator of claim 4; and an acid reactive compound.

6. The composition of claim 5, further comprising an acid-diffusion controller.

7. The composition of claim 5, wherein the acid reactive compound is a resin (B) whose solubility in a developing solution changes by an acid, the resin (B) having at least one of units represented by following formulas (3a) to (3d), ##STR00139## where: in the formulas (3a) to (3d), R.sup.1 is any one selected from the group consisting of: a hydrogen atom; an alkyl group; and a halogenated alkyl group; each of R.sup.2 and R.sup.3 is independently a linear, branched or cyclic alkyl group; R.sup.4 is a linear, branched or cyclic alkyl group which may have a substituent (C); the substituent (C) is selected from the group consisting of a hydroxyl group, an alkoxy group, an oxo group, an amino group and an alkylamino group; two or more of R.sup.2, R.sup.3 and R.sup.4 may be bonded each other directly with a single bond or through any one selected from the group consisting of a methylene group to form a ring structure; each of R.sup.5 and R.sup.6 is any one independently selected from the group consisting of: a hydrogen atom,; and a linear, branched or cyclic alkyl group; R.sup.7 is a linear, branched or cyclic alkyl group which may have the substituent (D); the substituent (D) is selected from the group consisting of a hydroxyl group, an alkoxy group, an oxo group, an amino group and an alkylamino group; two or more of R.sup.5, R.sup.6, and R.sup.7 may be bonded to each other directly with a single bond or through any one selected from the group consisting of a methylene group to form a ring structure; L.sup.1 is any one selected from the group consisting of: a direct bond; a carbonyloxy group; a carbonylamino group; a linear, branched or cyclic alkylenecarbonyloxy group; and a linear, branched or cyclic alkylenecarbonylamino group; each of R.sup.8 is any one independently selected from the group consisting of: an alkyl group; a hydroxy group; an alkoxy group; an alkylcarbonyl group; an alkylsulfanyl group; an alkylsulfinyl group; an alkylsulfonyl group; an amino group; a cyano group; a nitro group; and a halogen atom; 1 is an integer of 1 to 2; m is an integer of 0 to 4 when l is 1, and an integer of 0 to 6 when l is 2; n is an integer of 1 to 5 when l is 1, and an integer of 1 to 7 when l is 2; and m+n is 1 to 5 when l is 1, and 1 to 7 when l is 2.

8. The composition of claim 7, wherein: the resin (B) has at least one of units represented by following general formulas (4a) to (4b); or the composition further comprises a resin (C) having at least one of units represented by following general formulas (4a) to (4b), ##STR00140## where: in the general formulas (4a) and (4b), each of R.sup.1, R.sup.8 and L.sup.1 is independently selected from a same option as each of R.sup.1, R.sup.8 and L.sup.1 in the formulas (3a)-(3d); R.sup.9 is a cyclic group having at least one selected from the group consisting of —C(O)—O—, —SO.sub.2— and —O—SO.sub.2—; p is an integer of 0 to 4; and q is an integer of 1 to 5.

9. The composition of claim 5, wherein the photoacid generator is an acid-generator unit-containing resin in which X.sup.− in the onium salt has a unit represented by a following general formula (5), ##STR00141## where: in the general formula (5), R.sup.1 is any one selected from the group consisting of: a hydrogen atom; an alkyl group; and a halogenated alkyl group; L.sup.1 is any one selected from the group consisting of: a direct bond; a carbonyloxy group; a carbonylamino group; a linear, branched or cyclic alkylene carbonyloxy group; and a linear, branched or cyclic alkylenecarbonylamino group; Z.sup.1 is any one selected from the group consisting of: a linear or branched alkylene group having 1 to 12 carbon atoms; a linear or branched alkenylene group having 1 to 12 carbon atoms; and an arylene group having 6 to 14 carbon atoms; a part or all of hydrogen atoms of the alkylene group, the alkenylene group and the arylene group may be substituted with a fluorine atom; and at least one methylene group in the alkylene group, the alkenylene group and the arylene group may be substituted with a divalent hetero atom-containing group.

10. A method of manufacturing a device, comprising: forming a resist film by applying the composition of claim 5 to a substrate; irradiating the resist film with a first active energy ray; irradiating a resist film after irradiating with the first active energy ray, with a second active energy ray; and obtaining a pattern by developing a resist film after irradiating with the second active energy ray.

11. The method of claim 10, wherein a wavelength of the first active energy ray is shorter than a wavelength of the second active energy ray.

12. The method of claim 11, wherein the first active energy ray is an electron beam or an extreme ultraviolet.

13. The method of claim 10, further comprising heating with a heating wire or a laser between irradiating with the first active energy ray and irradiating with the second active energy ray.

14. The method of claim 10, wherein the method further comprises: generating a first active species from the composition in the resist film by irradiating with the first active energy ray; changing a structure of the photoacid generator by the first active species; and generating a second active species from a structure-changed photoacid generator by irradiating with the second active energy ray.

15. The method of claim 14, wherein the structure-changed photoacid generator is a ketone derivative.

Description

EXAMPLES

(1) Hereinafter, the present invention will be described in more detail by examples, but the present invention is not limited by these examples at all.

(2) <1>Synthesis of Sulfonium Salt

(3) <Synthesis of Sulfonium Salt 1>

Synthesis Example 1

Synthesis of 4-fluoro-4′-methylsulfanylbenzophenone

(4) 4-Bromothioanisole (8.0 g) is dissolved in tetrahydrofuran (32 g), and a 1 mol/L THF solution (39 ml) of methylmagnesium bromide is added dropwise thereto at 5° C. or lower. After dropwise addition, a mixture is stirred at 35° C. for 30 minutes to obtain a THF solution of 4-methylsulfanylphenylmagnesium bromide. 4-Fluorobenzoyl chloride (7.0 g) is dissolved in THF (15 g), the THF solution of 4-methylsulfanylphenylmagnesium bromide is added dropwise thereto at 10° C. or lower, and a mixture is stirred at 25° C. for 1 hour. After stirring, 10% by mass of aqueous solution (50 g) of ammonium chloride is added thereto at 20° C. or lower, a mixture is further stirred for 10 minutes, and an organic layer is extracted with ethyl acetate (80 g). An extract is washed with water, and then ethyl acetate and tetrahydrofuran are evaporated to obtain a crude crystal. The crude crystal is recrystallized with ethanol (120 g) to obtain 4-fluoro-4′-methylsulfanylbenzophenone (6.1 g).

(5) ##STR00047##

Synthesis Example 2

Synthesis of 4-methylsulfanyl-4′-phenylsulfanylbenzophenone

(6) 4-Fluoro-4′-methylsulfanylbenzophenone (6.0 g) obtained in Synthesis Example 1 is dissolved in DMF (30 g), thiophenol (3.2 g) and potassium carbonate (4.0 g) are added thereto, and a mixture is stirred at 70° C. for 4 hours. After stirring, pure water (90 g) is added thereto, a mixture is further stirred for 10 minutes, and an organic layer is extracted with toluene (60 g). An extract is washed three times with water, and then toluene is evaporated to obtain a crude crystal. The crude crystal is recrystallized with ethanol (40 g) to obtain 4-methylsulfanyl-4′-phenylsulfanylbenzophenone (5.6 g).

(7) ##STR00048##

Synthesis Example 3

Synthesis of dimethyl-[4-(4-phenylsulfanyl) benzoylphenyl]sulfonium-nonafluorobutanesulfonate

(8) 4-Methylsulfanyl-4′-phenylsulfanylbenzophenone (3.0 g) obtained in Synthesis Example 2 is dissolved in acetonitrile (20 g), dimethyl sulfate (2.8 g) is added thereto, and a mixture is stirred at 70° C. for 4 hours. After stirring, pure water (60 g) is added thereto, a mixture is further stirred for 10 minutes, and washed with toluene (40 g). To an obtained aqueous layer, potassium nonafluorobutanesulfonate (3.0 g) and methylene chloride (30 g) are added, and a mixture is stirred for about 1 hour. A stirred mixture is phase-separated, washed three times with water, and then methylene chloride is evaporated to obtain a crude crystal. The crude crystal is purified by silica gel column chromatography (methylene chloride/methanol=90/10 (volume ratio)) to obtain dimethyl-[4-(4-phenylsulfanyl) benzoylphenyl]sulfonium-nonafluorobutanesulfonate (4.9 g).

(9) ##STR00049##

Synthesis Example 4

Synthesis of {4-[dimethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}dimethylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 1)

(10) Dimethyl-[4-(4-phenylsulfanyl) benzoylphenyl]sulfonium-nonafluorobutanesulfonate (1.0 g) obtained in Synthesis Example 3 is dissolved in methanol (2.5 g), trimethyl orthoformate (1.0 g) and concentrated sulfuric acid (4.0 mg) are added thereto, and a mixture is stirred at 60° C. for 2 hours. After stirring, a reaction solution is added to a mixed solution of methylene chloride (30 g) and 3% by mass of aqueous solution (10 g) of sodium hydrogen carbonate, a mixture is stirred for 10 minutes, and an organic layer is recovered. The obtained organic layer is washed three times with water, and then methylene chloride is evaporated to obtain {4-[dimethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}dimethylsulfonium-nonafluorobutanesulfonate (1.0 g).

(11) ##STR00050##
<Synthesis of Sulfonium Salt 2>

Synthesis Example 5

Synthesis of {4-[diethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}dimethylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 2)

(12) {4-[Diethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}dimethylsulfonium-nonafluorobutanesulfonate (1.2 g) is obtained in the same procedure as Synthesis Example 4 except that ethanol is used instead of methanol and triethyl orthoformate is used instead of trimethyl orthoformate.

(13) ##STR00051##
<Synthesis of Sulfonium Salt 3>

Synthesis Example 6

Synthesis of ethyl-[4-(4-phenylsulfanylbenzoyl) phenyl]methylsulfonium-4-(3-hydroxyadamantylcarbonyloxy)-1,1,2-trifluorobutanesulfonate

(14) Ethyl-[4-(4-phenylsulfanylbenzoyl) phenyl]methylsulfonium-4-(3-hydroxyadamantylcarbonyloxy)-1,1,2-trifluorobutanesulfonate (5.1 g) is obtained in the same procedure as Synthesis Example 3 except that diethyl sulfate is used instead of dimethyl sulfate and sodium 4-(3-hydroxyadamantylcarbonyloxy)-1,1,2-trifluorobutanesulfonate is used instead of potassium nonafluorobutanesulfonate. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.6 cm.sup.2/mol or greater.

(15) ##STR00052##

Synthesis Example 7

Synthesis of {4-[dimethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}ethylmethylsulfnoium-4-(3-hydroxyadamantylcarbonyloxy)-1,1,2-trifluorobutanesulfonate (Sulfonium Salt 3)

(16) {4-[Dimethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}ethylmethylsulfonium-4-(3-hydroxyadamantylcarbonyloxy)-1,1,2-trifluorobutanesulfonate (1.1 g) is obtained in the same procedure as Synthesis Example 4 except that ethyl-[4-(4-phenylsulfanylbenzoyl) phenyl]methylsulfonium-4-(3-hydroxyadamantylcarbonyloxy)-1,1,2-trifluorobutanesulfonate is used instead of {4-[dimethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}dimethylsulfonium-nonafluorobutanesulfonate. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller, which is one-tenth or smaller in comparison with that of ethylmethyl-[4-(4-phenylsulfanyl-benzoyl) phenyl]sulfonium-4-(3-hydroxyadamantylcarbonyloxy)-1,1,2-trifluorobutanesulfonate obtained in Synthesis Example 6.

(17) ##STR00053##
<Synthesis of Sulfonium Salt 4>

Synthesis Example 8

Synthesis of 4-methylsulfanyl-4′-(4-methoxyphenylsulfanyl)benzophenone

(18) 4-Methylsulfanyl-4′-(4-methoxyphenylsulfanyl)benzophenone (4.6 g) is obtained in the same procedure as Synthesis Example 2 except that 4-methoxythiophenol is used instead of thiophenol.

(19) ##STR00054##

Synthesis Example 9

Synthesis of {4-[4-(4-methoxyphenylsulfanyl)benzoyl]phenyl}-dimethyl-sulfonium-camphorsulfonate

(20) Dimethyl-{4-[4-(4-methoxyphenylsulfanyl) benzoyl]phenyl}sulfonium-camphorsulfonate (4.3 g) is obtained in the same procedure as Synthesis Example 3 except that 4-methylsulfanyl-4′-(4-methoxyphenylsulfanyl)benzophenone is used instead of 4-methylsulfanyl-4′-phenylsulfanylbenzophenone and sodium (±)-10-camphorsulfonate is used instead of potassium nonafluorobutanesulfonate. A molar absorption coefficient at 365 nm of the obtained compound is 3.0×10.sup.6 cm.sup.2/mol or greater.

(21) ##STR00055##

Synthesis Example 10

Synthesis of {4-{dimethoxy-[4-(4-methoxyphenylsulfanyl)phenyl]methyl}phenyl}dimethylsulfonium-camphorsulfonate (Sulfonium Salt 4)

(22) Dimethyl-{4-[4-(4-methoxyphenylsulfanyl) benzoyl]phenyl}sulfonium-camphorsulfonate (1.0 g) is dissolved in methanol (2.5 g), trimethyl orthoformate (1.0 g) and (+/−)-10-camphorsulfonic acid (50 mg) are added thereto, and a mixture is stirred at 60° C. for 6 hours. After stirring, a reaction solution is added to a mixed solution of methylene chloride (30 g) and 3% by mass of aqueous solution (10 g) of sodium hydrogen carbonate, a mixture is stirred for 10 minutes, and an organic layer is recovered. The obtained organic layer is washed three times with water, and then methylene chloride is evaporate to obtain {4-{dimethoxy-[4-(4-methoxyphenylsulfanyl)phenyl]methyl}phenyl}dimethylsulfonium-camphorsulfonate (1.0 g). A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller, which is one-tenth or smaller in comparison with that of dimethyl-{4-[4-(4-methoxyphenylsulfanyl)benzoyl]phenyl}-sulfonium-camphorsulfonate obtained in Synthesis Example 9.

(23) ##STR00056##
<Synthesis of Sulfonium Salt 5>

Synthesis Example 11

Synthesis of 2-phenylsulfanylbenzoic acid

(24) 2-Mercaptobenzoic acid (9.2 g) is dissolved in DMF (60 g), bromobenzene (9.4 g), potassium carbonate (10 g) and copper (I) chloride (6.0 g) are added thereto, and a mixture is stirred at 90° C. for 6 hours. After stirring, pure water (180 g) is added thereto, a mixture is further stirred for 10 minutes, and an organic layer is extracted with methylene chloride (120 g). An extract is washed three times with water, and then methylene chloride is evaporated to obtain a crude crystal. The crude crystal is recrystallized with ethanol (80 g) to obtain 2-phenylsulfanylbenzoic acid (10.6 g).

(25) ##STR00057##

Synthesis Example 12

Synthesis of 2-phenylsulfanylbenzoyl chloride

(26) Thionyl chloride (60 g) is added to 2-phenylsulfanylbenzoic acid (10.0 g) obtained in Synthesis Example 11, and a mixture is stirred at 60° C. for 4 hours. After stirring, thionyl chloride is evaporated under reduced pressure to obtain 2-phenylsulfanylbenzoyl chloride (10.8 g).

(27) ##STR00058##

Synthesis Example 13

Synthesis of 4-methylsulfanyl-2′-phenylsulfanylbenzophenone

(28) 4-Methylsulfanyl-2′-phenylsulfanylbenzophenone (6.5 g) is obtained in the same procedure as Synthesis Example 1 except that 2-phenylsulfanylbenzoyl chloride is used instead of 4-fluorobenzoyl chloride.

(29) ##STR00059##

Synthesis Example 14

Synthesis of dimethyl-[4-(2-phenylsulfanylbenzoyl) phenyl]sulfonium-methylsulfate

(30) 4-Methylsulfanyl-2′-phenylsulfanylbenophenone (3.0 g) is dissolved in acetonitrile (10 g), dimethyl sulfate (2.8 g) is added thereto, and a mixture is stirred at 70° C. for 4 hours. After stirring, a reaction solution is added dropwise to ethyl acetate (40 g) to precipitate a solid. The solid is filtered, washed with ethyl acetate (10 g), and then dried to obtain dimethyl-[4-(2-phenylsulfanylbenzoyl) phenyl]sulfonium-methylsulfate (4.1 g). A molar absorption coefficient at 365 nm of the obtained compound is 5.0×10.sup.5 cm.sup.2/mol or greater.

(31) ##STR00060##

Synthesis Example 15

Synthesis of {4-[dimethoxy-(2-phenylsulfanylphenyl)methyl]phenyl}dimethylsulfonium-benzoate (Sulfonium Salt 5)

(32) Dimethyl-[4-(2-phenylsulfanyl-benzoyl) phenyl]sulfonium-methylsulfate (3.0 g) obtained in Synthesis Example 14 is dissolved in methanol (7.5 g), trimethyl orthoformate (3.0 g) and concentrated sulfuric acid (12.0 mg) are added thereto, and a mixture is stirred at 60° C. for 2 hours. After stirring, a reaction solution is added dropwise to 3% by mass of aqueous solution (30 g) of sodium hydrogen carbonate. Then, methylene chloride (30 g) and sodium benzoate (3.0 g) are added thereto, and a mixture is further stirred for 3 hours. After stirring, phase separation is performed to recover an organic layer, the organic layer is washed three times with water, and then methylene chloride is evaporated to obtain a crude crystal. The crude crystal is purified by silica gel column chromatography (methylene chloride/methanol=90/10 (volume ratio), addition of 0.1% by mass triethylamine) to obtain {4-[dimethoxy-(2-phenylsulfanylphenyl)methyl]phenyl}dimethylsulfonium-benzoate (1.2 g). A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller, which is one-fifth or smaller in comparison with that of dimethyl-[4-(2-phenylsulfanyl-benzoyl) phenyl]sulfonium-methylsulfate obtained in Synthesis Example 14.

(33) ##STR00061##
<Synthesis of Sulfonium Salt 6>

Synthesis Example 16

Synthesis of 2,4-dimethoxy-4′-fluorobenzophenone

(34) Aluminum chloride (3.0 g) is added to methylene chloride (28 g), and set to 0° C. 2,4-Dimethoxybenzene (3.0 g) is added thereto, and then 4-fluorobenzoyl chloride (3.4 g) is dissolved in methylene chloride (6.8 g) to add dropwise thereto over 30 minutes. After dropwise addition, a mixture is stirred at 25° C. for 1 hour, pure water (60 g) is added thereto, a mixture is further stirred for 5 minutes, and extracted twice with toluene (20 g). A mixture is phase-separated to obtain an organic layer, and a solvent is evaporated. An obtained residue is purified by recrystallization with ethanol (30 g) to obtain 2,4-dimethoxy-4′-fluorobenzophenone (5.2 g).

(35) ##STR00062##

Synthesis Example 17

Synthesis of 2,4-dimethoxy-4′-(n-propylsulfanyl)benzophenone

(36) 2,4-Dimethoxy-4′-fluorobenzophenone obtained (5.0 g) in Synthesis Example 16 is dissolved in DMF (30 g), 1-propanethiol (1.6 g) and potassium carbonate (3.2 g) are added thereto, and a mixture is stirred 70° C. for 4 hours. After stirring, pure water (90 g) is added thereto, a mixture is further stirred for 10 minutes, and an organic layer is extracted with toluene (60 g). An extract is washed three times with water, and then toluene is evaporated to obtain a crude product. The crude product is purified by silica gel column chromatography (hexane/ethyl acetate=75/25 (volume ratio)) to obtain 2,4-dimethoxy-4′-(n-propylsulfanyl)benzophenone (4.8 g).

(37) ##STR00063##

Synthesis Example 18

Synthesis of [4-(2,4-dimethoxybenzoyl) phenyl]ethyl-n-propylsulfonium-nonaflurobutanesulfonate

(38) [4-(2, 4-Dimethoxybenzoyl)phenyl]ethyl-n-propylsulfonium-nonaflurobutanesulfonate (5.0 g) is obtained in the same procedure as Synthesis Example 3 except that 2,4-dimethoxy-4′-(n-propylsulfanyl)benzophenone is used instead of 4-methylsulfanyl-4′-phenylsulfanylbenzophenone and diethyl sulfate is used instead of dimethyl sulfate. A molar absorption coefficient at 365 nm of the obtained compound is 5.0×10.sup.5 cm.sup.2/mol or greater.

(39) ##STR00064##

Synthesis Example 19

Synthesis of {4-[(2,4-dimethoxyphenyl)-dimethoxy-methyl]phenyl}ethyl-n-propylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 6)

(40) {4-[(2,4-Dimethoxyphenyl) dimethoxymethyl]phenyl}ethyl-n-propylsulfonium-nonafluorobutanesulfonate (5.1 g) is obtained in the same procedure as Synthesis Example 4 except that [4-(2,4-dimethoxybenzoyl) phenyl]ethyl-n-propylsulfonium-nonaflurobutanesulfonate is used instead of dimethyl-[4-(4-phenylsulfanylbenzoyl) phenyl]sulfonium-nonafluorobutanesulfonate. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller, which is one-fifth or smaller in comparison with that of {4-(2,4-dimethoxybenzoyl)phenyl}ethyl-n-propylsulfonium-nonafluorobutanesulfonate obtained in Synthesis Example 18.

(41) ##STR00065##
<Synthesis of Sulfonium Salt 7>

Synthesis Example 20

Synthesis of 4-bromo-4′-phenylsulfanylbenzophenone

(42) Aluminum chloride (3.0 g) is dissolved in methylene chloride (28 g), and set to 0° C. Diphenyl sulfide (4.0 g) is added thereto, and then 4-bromobenzoyl chloride (3.4 g) is dissolved in methylene chloride (6.8 g) to add dropwise thereto over 30 minutes. After dropwise addition, a mixture is stirred at 25° C. for 1 hour, pure water (60 g) is added thereto, a mixture is further stirred for 5 minutes, and then washed twice with toluene (20 g). A mixture is phase-separated to obtain an organic layer, and a solvent is evaporated. An obtained residue is purified by recrystallization with isopropyl alcohol (30 g) to obtain 4-bromo-4′-phenylsulfanylbenzophenone (5.2 g).

(43) ##STR00066##

Synthesis Example 21

Synthesis of 4-bromo-4′-phenylsulfanylbenzophenone dimethyl acetal

(44) 4-Bromo-4′-phenylsulfanylbenzophenone (5.0 g) obtained in Synthesis Example 20 is dissolved in methanol (30 g), trimethyl orthoformate (5.0 g) and concentrated sulfuric acid (30 mg) are added thereto, and a mixture is stirred at 60° C. for 4 hours. After stirring, 3% by mass of aqueous solution (150 g) of sodium bicarbonate is added thereto, and a mixture is further stirred for 10 minutes to precipitate a solid. The precipitated solid is filtered, and re-dissolved in methylene chloride (30 g). A solution is washed three times with water, and then methylene chloride is evaporated to obtain 4-bromo-4′-phenylsulfanylbenzophenone dimethyl acetal (5.0 g).

(45) ##STR00067##

Synthesis Example 22

Synthesis of {4-[dimethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}diphenylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 7)

(46) To a flask dried in advance, tetrahydrofuran (2.0 g), magnesium (0.4 g) and 1,2-dibromoethane are added to activate magnesium. After check of the activation, a solution is heated to 50° C., and then 4-bromo-4′-phenylsulfanylbenzophenone dimethyl acetal (4.0 g) obtained in Synthesis Example 20 is dissolved in THF (6.0 g) to add dropwise thereto. After dropwise addition, a mixture is stirred at 50° C. for 5 hours to obtain a THF solution of 4-[dimethoxy-(4-phenylsulfanylphenyl)methyl]phenylmagnesium bromide. To a solution of diphenyl sulfoxide (1.9 g), trimethylsilyl chloride (1.8 g) and triethylamine (0.8 g) dissolved in methylene chloride (9.5 g), the THF solution of 4-[dimethoxy-(4-phenylsulfanylphenyl)methyl]phenylmagnesium bromide is added dropwise at 10° C. or lower, and then a mixture is stirred at 25° C. for 1 hour. After stirring, 10% by mass of aqueous solution (30 g) of ammonium chloride is added thereto at 5° C. or lower, a mixture is further stirred for 10 minutes, and washed twice with isopropyl ether (5.0 g). Thereafter, methylene chloride (40 g) and potassium nonafluorobutanesulfonate (3.1 g) are added thereto, and a mixture is stirred at 25° C. for about 2 hours. A stirred mixture is phase-separated, washed three times with water, and then methylene chloride is evaporated to obtain a crude crystal. The crude crystal is purified by silica gel column chromatography (methylene chloride/methanol=90/10 (volume ratio)) to obtain {4-[dimethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}diphenylsulfonium-nonafluorobutanesulfonate (3.2 g). A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller.

(47) ##STR00068##
<Synthesis of Sulfonium Salt 8>

Synthesis Example 23

Synthesis of 2-(4-bromophenyl)-2-(4-phenylsulfanylphenyl)-[1,3]dioxolane

(48) 2-(4-Bromophenyl)-2-(4-phenylsulfanylphenyl)-[1,3]dioxolane (5.0 g) is obtained in the same procedure as Synthesis Example 21 except that ethylene glycol is used instead of methanol.

(49) ##STR00069##

Synthesis Example 24

Synthesis of diphenyl-{4-[2-(4-phenylsulfanylphenyl)-[1,3]dioxolan-2-yl]phenyl}sulfonium-nonafluorobutanesulfonate (Sulfonium Salt 8)

(50) Diphenyl-{4-[2-(4-phenylsulfanylphenyl)-[1,3]dioxolan-2-yl]phenyl}sulfonium-nonafluorobutanesulfonate (4.3 g) is obtained in the same procedure as Synthesis Example 22 except that 2-(4-bromophenyl)-2-(4-phenylsulfanylphenyl)-[1,3]dioxolane is used instead of 4-bromo-4′-phenylsulfanylbenzophenone dimethyl acetal. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller.

(51) ##STR00070##
<Synthesis of Sulfonium Salt 9>

Synthesis Example 25

Synthesis of dibenzothiophene-5-oxide

(52) Dibenzothiophene (15 g) is dissolved in formic acid (75 g), and 35% by mass of aqueous solution (8.7 g) of hydrogen peroxide is added dropwise with ice cooling. Then, a mixture is allow to reach room temperature, and stirred for 5 hours. After stirring, pure water (200 g) is added dropwise to a reaction mixture to precipitate a solid. The precipitated solid is filtered, washed three times with pure water (40 g), and then dried to obtain a crude crystal. The crude crystal is recrystallized with acetone (100 g) and ethanol (200 g) to obtain dibenzothiophene-5-oxide (12 g).

(53) ##STR00071##

Synthesis Example 26

Synthesis of 5-{4-[dimethoxy-(4-phenylsulfanylphenyl) methyl]phenyl}dibenzothiophenium-nonafluorobutanesulfonate (Sulfonium Salt 9)

(54) 5-{4-[Dimethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}dibenzothiophenium-nonafluorobutanesulfonate (4.0 g) is obtained in the same procedure as Synthesis Example 22 except that dibenzothiophene-5-oxide is used instead of diphenyl sulfoxide. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller.

(55) ##STR00072##
<Synthesis of Sulfonium Salt 10>

Synthesis Example 27

Synthesis of {4-[dimethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}(di-p-tolyl)sulfonium-p-toluenesulfonate (Sulfonium Salt 10)

(56) {4-[Dimethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}(di-p-tolyl)sulfonium-p-toluenesulfonate (3.8 g) is obtained in the same procedure as Synthesis Example 22 except that p-tolyl sulfoxide is used instead of diphenyl sulfoxide and sodium p-toluenesulfonate is used instead of potassium nonafluorobutanesulfonate. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller.

(57) ##STR00073##
<Synthesis of Sulfonium Salt 11>

Synthesis Example 28

Synthesis of (6-methoxynaphthalen-2-yl)-(4-methylsulfanylphenyl)methanone

(58) (6-Methoxynaphthalen-2-yl)-(4-methylsulfanylphenyl)methanone (4.5 g) is obtained in the same procedure as Synthesis Example 1 except that 2-bromo-6-methoxynaphthalene is used instead of 4-bromoanisole and 4-(methylthio)benzoyl chloride is used instead of 4-fluorobenzoyl chloride.

(59) ##STR00074##

Synthesis Example 29

Synthesis of [4-(6-methoxynaphthalen-2-ylcarbonyl)phenyl]dimethylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 11)

(60) [4-(6-Methoxynaphthalen-2-ylcarbonyl)phenyl]dimethylsulfonium-nonafluorobutanesulfonate (4.5 g) is obtained in the same procedure as Synthesis Example 3 except that (6-methoxynaphthalen-2-yl)-(4-methylsulfanylphenyl)methanone is used instead of 4-methylsulfanyl-4′-phenylsulfanylbenzophenone. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.6 cm.sup.2/mol or greater.

(61) ##STR00075##

Synthesis Example 30

Synthesis of {4-[dimethoxy-(6-methoxynaphthalen-2-yl) methyl]phenyl}dimethylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 11)

(62) {4-[Dimethoxy-(6-methoxynaphthalen-2-yl)methyl]phenyl}dimethylsulfonium-nonafluorobutanesulfonate (1.0 g) is obtained in the same procedure as Synthesis Example 4 except that {4-(6-methoxynaphthalen-2-ylcarbonyl)phenyl}dimethylsulfonium-nonafluorobutanesulfonate is used instead of dimethyl-[4-(4-phenylsulfanyl-benzoyl)phenyl]-sulfonium-nonafluorobutanesulfonate. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller, which is one-tenth or smaller in comparison with that of {4-(6-methoxynaphthalen-2-ylcarbonyl)phenyl}dimethylsulfonium-nonafluorobutanesulfonate obtained in Synthesis Example 29.

(63) ##STR00076##
<Synthesis of Sulfonium Salt 12>

Synthesis Example 31

Synthesis of 6-bromonaphthoyl-2-chloride

(64) 6-Bromonaphthoyl-2-chloride (10.8 g) is obtained in the same procedure as Synthesis Example 12 except that 6-bromo-2-naphthalenecarboxylic acid is used instead of 2-phenylsulfanylbenzoic acid.

(65) ##STR00077##

Synthesis Example 32

Synthesis of (6-bromonaphthalen-2-yl)-(4,7-dimethoxynaphthalen-1-yl)methanone

(66) (6-Bromonaphthalen-2-yl)-(4,7-dimethoxynaphthalen-1-yl)methanone (5.4 g) is obtained in the same procedure as Synthesis Example 20 except that 1,6-dimethoxynaphthalene is used instead of diphenyl sulfide and 6-bromonaphthoyl-2-chloride is used instead of 4-bromobenzoyl chloride.

(67) ##STR00078##

Synthesis Example 33

Synthesis of 4-[(6-bromonaphthalen-2-yl) dimethoxymethyl]-1,6-dimethoxynaphthalene

(68) 4-[(6-Bromonaphthalen-2-yl)dimethoxymethyl]-1,6-dimethoxynaphthalene (5.1 g) is obtained in the same procedure as Synthesis Example 21 except that (6-bromonaphthalen-2-yl)-(4,7-dimethoxynaphthalen-1-yl)methanone is used instead of 4-bromo-4′-phenylsulfanylbenzophenone.

(69) ##STR00079##

Synthesis Example 34

Synthesis of {6-[(4,7-dimethoxynaphthalen-1-yl) dimethoxymethyl]naphthalen-2-yl}diphenylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 12)

(70) {6-[(4,7-Dimethoxynaphthalen-1-yl)dimethoxymethyl]naphthalen-2-yl}diphenylsulfonium-nonafluorobutanesulfonate (4.0 g) is obtained in the same procedure as Synthesis Example 22 except that 4-[(6-bromonaphthalen-2-yl)-dimethoxy-methyl]-1,6-dimethoxynaphthalene is used instead of 4-bromo-4′-phenylsulfanylbenzophenone dimethyl acetal. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller.

(71) ##STR00080##
<Synthesis of Sulfonium Salt 13>

Synthesis Example 35

Synthesis of 4-(4-bromophenylsulfanyl)benzophenone

(72) 4-(4-Bromophenylsulfanyl)benzophenone (5.8 g) is obtained in the same procedure as Synthesis Example 2 except that 4-fluorobenzophenone is used instead of 4-fluoro-4′-methylsulfanylbenzophenone and 4-bromothiophenol is used instead of thiophenol.

(73) ##STR00081##

Synthesis Example 36

Synthesis of 4-(4-bromophenylsulfanyl)benzophenone dimethyl acetal

(74) 4-(4-Bromophenylsulfanyl)benzophenone dimethyl acetal (5.1 g) is obtained in the same procedure as Synthesis Example 21 except that

(75) 4-(4-bromophenylsulfanyl)benzophenone is used instead of 4-bromo-4′-phenylsulfanylbenzophenone.

(76) ##STR00082##

Synthesis Example 37

Synthesis of {4-[4-(dimethoxy-phenyl-methyl)phenylsulfanyl]phenyl}diphenylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 13)

(77) {4-[4-(Dimethoxy-phenyl-methyl)phenylsulfanyl]phenyl}diphenylsulfonium-nonafluorobutanesulfonate (4.0 g) is obtained in the same procedure as Synthesis Example 22 except that 4-(4-bromophenylsulfanyl)benzophenone dimethyl acetal is used instead of 4-bromo-4′-phenylsulfanylbenzophenone dimethyl acetal. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller.

(78) ##STR00083##
<Synthesis of Sulfonium Salt 14>

Synthesis Example 38

Synthesis of (4-fluorophenyl)-(6-methoxynaphthalen-2-yl)methanone

(79) (4-Fluorophenyl)-(6-methoxynaphthalen-2-yl)methanone (4.3 g) is obtained in the same procedure as Synthesis Example 1 except that 2-bromo-6-methoxynaphthalene is used instead of 4-bromothioanisole.

(80) ##STR00084##

Synthesis Example 39

Synthesis of [4-(4-bromophenoxy)phenyl]-(6-methoxynaphthalen-2-yl)methanone

(81) [4-(4-Bromophenoxy)phenyl]-(6-methoxynaphthalen-2-yl)methanone (5.9 g) is obtained in the same procedure as Synthesis Example 2 except that (4-fluorophenyl)-(6-methoxynaphthalen-2-yl)methanone is used instead of 4-fluoro-4′-methylsulfanylbenzophenone and 4-bromophenol is used instead of thiophenol.

(82) ##STR00085##

Synthesis Example 40

Synthesis of 2-{[4-(4-bromophenoxy)phenyl]-dimethoxymethyl}-6-methoxynaphthalene

(83) 2-{[4-(4-Bromophenoxy)phenyl]-dimethoxymethyl}-6-methoxynaphthalene (5.0 g) is obtained in the same procedure as Synthesis Example 20 except that [4-(4-bromophenoxy)phenyl]-(6-methoxynaphthalen-2-yl)methanone is used instead of 4-bromo-4′-phenylsulfanylbenophenone.

(84) ##STR00086##

Synthesis Example 41

Synthesis of {4-{4-[dimethoxy-(6-methoxynaphthalen-2-yl)methyl]phenoxy}phenyl}diphenylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 14)

(85) {4-{4-[Dimethoxy-(6-methoxynaphthalen-2-yl)methyl]phenoxy}phenyl}diphenylsulfonium-nonafluorobutanesulfonate (4.0 g) is obtained in the same procedure as Synthesis Example 22 except that 2-{[4-(4-bromophenoxy)phenyl]-dimethoxymethyl}-6-methoxynaphthalene is used instead of 4-bromo-4′-phenylsulfanylbenzophenone dimethyl acetal. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller.

(86) ##STR00087##
<Synthesis of Iodonium Salt 1>

Synthesis Example 42

Synthesis of 2,4-dimethoxy-4′-iodobenzophenone

(87) 2,4-Dimethoxy-4′-iodobenzophenone (5.3 g) is obtained in the same procedure as Synthesis Example 16 except that 4-iodobenzoyl chloride is used instead of 4-fluorobenzoyl chloride.

(88) ##STR00088##

Synthesis Example 43

Synthesis of (4-t-butylphenyl)[4-(2,4-dimethoxybenzoyl)phenyl]iodonium-nonafluorobutanesulfonate

(89) 2,4-Dimethoxy-4′-iodobenzophenone (4 g) obtained in Synthesis Example 41 is added to sulfuric acid (16 g), then potassium persulfate (10 g) is added thereto in small portions at 10° C. or lower, and a mixture is stirred for 30 minutes. After stirring, t-butylbenzene (18 g) is added thereto, and a mixture is further stirred at 25° C. for 3 hours. After stirring, pure water (30 g) is added thereto at 10° C. or lower, then methylene chloride (40 g) and potassium nonafluorobutanesulfonate (3.7 g) is added thereto, and a mixture is stirred at 25° C. for about 2 hours. A stirred mixture is phase-separated, washed three times with water, and then methylene chloride is evaporated to obtain a crude product. The crude product is purified by silica gel column chromatography (methylene chloride/methanol=90/10 (volume ratio)) to obtain (4-t-butylphenyl)[4-(2,4-dimethoxybenzoyl)phenyl]iodonium-nonafluorobutanesulfonate (3.5 g). A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.6 cm.sup.2/mol or greater.

(90) ##STR00089##

Synthesis Example 44

Synthesis of (4-t-butylphenyl){4-[(2,4-dimethoxyphenyl)dimethoxymethyl]phenyl}iodonium-nonafluorobutanesulfonate (Iodonium Salt 1)

(91) (4-t-Butylphenyl)[4-[(2,4-dimethoxyphenyl)dimethoxymethyl]phenyl]iodonium-nonafluorobutanesulfonate (1.0 g) is obtained in the same procedure as Synthesis Example 4 except that (4-t-butylphenyl)[4-(2,4-dimethoxybenzoyl)phenyl]iodonium-nonafluorobutanesulfonate is used instead of dimethyl-[4-(4-phenylsulfanyl-benzoyl) phenyl]sulfonium-nonafluorobutanesulfonate. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller, which is one-tenth or smaller in comparison with that of (4-t-butylphenyl)[4-(2,4-dimethoxybenzoyl)phenyl]iodonium-nonafluorobutanesulfonate obtained in Synthesis Example 43.

(92) ##STR00090##
<Synthesis of Iodonium Salt 2>

Synthesis Example 45

Synthesis of (4, 7-dimethoxynaphthalen-1-yl)-(4-iodophenyl)methanone

(93) (4,7-Dimethoxynaphthalen-1-yl)-(4-iodophenyl)methanone (5.4 g) is obtained in the same procedure as Synthesis Example 19 except that 1,6-dimethoxynaphthalene is used instead of diphenyl sulfide and 4-iodobenzoyl chloride is used instead of 4-bromobenzoyl chloride.

(94) ##STR00091##

Synthesis Example 46

Synthesis of [4-(4,7-dimethoxynaphthalen-1-ylcarbonyl)phenyl]phenyliodonium-nonafluorobutanesulfonate

(95) [4-(4,7-Dimethoxynaphthalen-1-ylcarbonyl)phenyl]phenyliodonium-nonafluorobutanesulfonate (3.3 g) is obtained in the same procedure as Synthesis Example 42 except that (4,7-dimethoxynaphthalen-1-yl)-(4-iodophenyl)methanone is used instead of 2,4-dimethoxy-4′-iodobenzophenone. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.6 cm.sup.2/mol or greater.

(96) ##STR00092##

Synthesis Example 47

Synthesis of {4-[(4,7-dimethoxynaphthalen-1-yl)dimethoxymethyl]phenyl}phenyliodonium-nonafluorobutanesulfonate (Iodonium Salt 2)

(97) {4-[(4,7-Dimethoxynaphthalen-1-yl)-dimethoxy-methyl]phenyl}phenyliodonium-nonafluorobutanesulfonate (1.0 g) is obtained in the same procedure as Synthesis Example 4 except that {4-(4,7-dimethoxynaphthalene-1-carbonyl)phenyl}phenyliodonium-nonafluorobutanesulfonate is used instead of dimethyl-[4-(4-phenylsulfanylbenzoyl)phenyl]sulfonium-nonafluorobutanesulfonate. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller, which is one-tenth or smaller in comparison with that of {4-(4,7-dimethoxynaphthalen-1-ylcarbonyl)phenyl}phenyliodonium-nonafluorobutanesulfonate obtained in Synthesis Example 46.

(98) ##STR00093##
<Synthesis of Sulfonium Salt 15>

Synthesis Example 48

Synthesis of {4-[dimethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}diphenylsulfonium-p-styrenesulfonate (Sulfonium Salt 15)

(99) {4-[Dimethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}diphenylsulfonium-p-styrenesulfonate (2.8 g) is obtained in the same procedure as Synthesis Example 22 except that sodium p-styrenesulfonate hydrate is used instead of potassium nonafluorobutanesulfonate. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller.

(100) ##STR00094##
<Synthesis of Sulfonium Salt 16>

Synthesis Example 49

Synthesis of {4-[dimethoxy-(4-phenylsulfanylphenyl) methyl]phenyl}diphenylsulfonium-(4-methacryloyl-1,1,2-trifluorobutanesulfonate) (Sulfonium Salt 16)

(101) {4-[Dimethoxy-(4-phenylsulfanylphenyl)methyl]phenyl}diphenylsulfonium-(4-methacryloyl-1,1,2-trifluorobutanesulfonate) (3.0 g) is obtained in the same procedure as Synthesis Example 22 except that sodium 4-methacryloyloxy-1,1,2-trifluorobutanesulfonate is used instead of potassium nonafluorobutanesulfonate. A molar absorption coefficient at 365 nm of the obtained compound is 1.0×10.sup.5 cm.sup.2/mol or smaller.

(102) ##STR00095##
<Synthesis of Sulfonium Salt 17>

Synthesis Example 50

Synthesis of 4-bromo-4′-phenylsulfinylbenzophenone

(103) Formic acid (53.3 g) is added to 4-bromo-4′-phenylsulfanylbenzophenone (10.1 g) obtained in Synthesis Example 20, a mixture is stirred at 50° C., then 35% by mass of aqueous solution (2.9 g) of hydrogen peroxide is added dropwise thereto in small portions, and a mixture is stirred at 50° C. After 1 hour, a reaction solution is cooled with ice cooling, and pure water (28.2 g) and toluene (80.3 g) are added thereto. A mixture is phase-separated, an organic layer is washed three times with pure water (30 g), and then an organic solvent is evaporated to obtain 4-bromo-4′-phenylsulfinylbenzophenone (10.0 g).

(104) ##STR00096##

Synthesis Example 51

Synthesis of 4-(4-hydroxyphenylsulfanyl)-4′-phenylsulfinylbenzophenone

(105) 4-Bromo-4′-phenylsulfinylbenzophenone (7.7 g), potassium carbonate (3.6 g) and 4-hydroxybenzenethiol (3.0 g) are dissolved in DMF (23.1 g), and a mixture is stirred at 60° C. After 2 hours, a reaction solution is cooled with ice cooling, and pure water (70 g) is added dropwise thereto to precipitate a solid. The precipitated solid is filtered, and re-dissolved in methylene chloride (40 g). A solution is washed three times with pure water (40 g), and then methylene chloride is evaporated to obtain a crude crystal. The crude crystal is purified by silica gel column chromatography (hexane/ethyl acetate=2/1 (volume ratio)) to obtain 4-(4-hydroxyphenylsulfanyl)-4′-phenylsulfinylbenzophenone (6.4 g).

(106) ##STR00097##

Synthesis Example 52

Synthesis of 4-(4-hydroxyphenylsulfanyl)-4′-phenylsulfinylbenzophenone dimethyl acetal

(107) 4-(4-Hydroxyphenylsulfanyl) -4′-phenylsulfinylbenzophenone dimethyl acetal (5.0 g) is obtained in the same procedure as Synthesis Example 21 except that 4-(4-hydroxyphenylsulfanyl)-4′-phenylsulfinylbenzophenone is used instead of 4-bromo-4′-phenylsulfanylbenzophenone.

(108) ##STR00098##

Synthesis Example 53

Synthesis of (4-{dimethoxy-[4-(4-hydroxyphenylsulfanyl)phenyl]methyl}phenyl)diphenylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 17)

(109) 4-(4-Hydroxyphenylsulfanyl)-4′-phenylsulfinylbenzophenone dimethyl acetal (5.0 g) is dissolved in dehydrated methylene chloride (30.0 g), and a 2 M THF solution (6.8 mL) of phenylmagnesium chloride is added dropwise thereto with ice cooling. Then, trichlorosilane (1.7 g) is added dropwise thereto, and a mixture is stirred for 1 hour. After stirring, 10% by mass of aqueous solution (30 g) of ammonium chloride is added thereto at 5° C. or lower, a mixture is further stirred, and washed twice with isopropyl ether (5.0 g). Then, methylene chloride (40 g) and potassium nonafluorobutanesulfonate (3.4 g) are added thereto, and a mixture is stirred at 25° C. for 2 hours. A stirred mixture is phase-separated, washed three times with pure water (20 g), and then methylene chloride is evaporated to obtain a crude crystal. The crude crystal is purified by silica gel column chromatography (methylene chloride/methanol=90/10 (volume ratio)) to obtain (4-{dimethoxy-[4-(4-hydroxyphenylsulfanyl)phenyl]methyl}phenyl) diphenylsulfonium-nonafluorobutanesulfonate (3.4 g).

(110) ##STR00099##
<Synthesis of Sulfonium Salt 18>

Synthesis Example 54

Synthesis of (2-hydroxy-9-oxo-9H-fluoren-3-yl)diphenylsulfonium-nonafluorobutanesulfonate

(111) 2-Hydroxy-9-fluorenone (1.0 g), diphenyl sulfoxide (1.0 g) and diphosphorus pentaoxide (0.4 g) are added to methanesulfonic acid (6.0 g), and a mixture is stirred with ice cooling. After 18 hours, pure water (20 g) is added dropwise to a reaction solution, and a mixture is washed twice with isopropyl ether (5.0 g). Then, methylene chloride (20 g) and potassium nonafluorobutanesulfonate (1.7 g) are added thereto, and a mixture is stirred at 25° C. for 2 hours. A stirred mixture is phase-separated, wash three times with pure water (10 g), and then methylene chloride is evaporated to obtain a crude crystal. The crude crystal is purified by silica gel column chromatography (methylene chloride/methanol=90/10 (volume ratio)) to obtain (2-hydroxy-9-oxo-9H-fluoren-3-yl)diphenylsulfonium-nonafluorobutanesulfonate (2.1 g).

(112) ##STR00100##

Synthesis Example 55

Synthesis of (2-hydroxy-9,9-dimethoxy-9H-fluoren-3-yl)diphenylsulfonium-nonafluorobutanesulfonate

(113) (2-Hydroxy-9,9-dimethoxy-9H-fluoren-3-yl)diphenylsulfonium-nonafluorobutanesulfonate (2.1 g) is obtained in the same procedure as Synthesis Example 21 except that (2-hydroxy-9-oxo-9H-fluoren-3-yl)diphenylsulfonium-nonafluorobutanesulfonate is used instead of 4-bromo-4′-phenylsulfanylbenzophenone.

(114) ##STR00101##

Synthesis Example 56

Synthesis of [spiro(1,3-dioxolane-2,9′-[9H]fluorene), 2′-hydrox-3′-yl]diphenylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 18)

(115) (2-Hydroxy-9,9-dimethoxy-9H-fluoren-3-yl) diphenylsulfonium-nonafluorobutanesulfonate (2.0 g) and ethylene glycol (0.7 g) are dissolved in dehydrated THF (16.0 g). Then, p-toluenesulfonic acid (48.0 mg) is added thereto, and a mixture is stirred at room temperature under nitrogen atmosphere. After 18 hours, triethylamine (0.2 g) was added to the reaction solution. THF is evaporated, then methylene chloride (20 g) and pure water (20 g) are added thereto. A mixture is phase-separated, washed twice with pure water (20 g), and then methylene chloride is evaporated to obtain {spiro(1,3-dioxolane-2,9′-[9H]fluorene),2′-hydrox-3′-yl}diphenylsulfonium-nonafluorobutanesulfonate (1.8 g).

(116) ##STR00102##
<Synthesis of Sulfonium Salt 19>

Synthesis Example 57

Synthesis of 1-(6-methoxy-2-naphthalenyl)-3-(4-methylphenyl)-2-propen-1-one.

(117) 2-Acetyl-6-methoxynaphthalene (1.6 g) and 4-methylbenzaldehyde (1.1) are dissolved in ethanol (16 g), and a mixture is stirred. 10% by mass of aqueous solution (0.4 g) of sodium hydroxide is added dropwise thereto with ice cooling, and a mixture is further stirred. After 3 hours, a precipitated solid in a reaction solution is filtered, and washed with ethanol (8 g). A recovered solid is dried to obtain 1-(6-methoxy-2-naphthalenyl)-3-(4-methylphenyl)-2-propen-1-one (2.2 g).

(118) ##STR00103##

Synthesis Example 58

Synthesis of {6-[3-(4-methylphenyl)-1-oxo-2-propenyl]-2-methoxynaphthalen-1-yl}diphenylsulfonium-nonafluorobutanesulfonate

(119) 1-(6-Methoxy-2-naphthalenyl)-3-(4-methylphenyl)-2-propen-1-one (0.8 g) and diphosphorus pentaoxide (0.3 g) are added to methanesulfonic acid (2.4 g), and a mixture is stirred. Diphenyl sulfoxide (0.4 g) is added thereto in small portions with ice cooling, and a mixture is further stirred. After 3 hours, pure water (20 g) is added dropwise thereto with ice cooling, a mixture is further stirred, and washed twice with isopropyl ether (5.0 g). Then, methylene chloride (20 g) and potassium nonafluorobutanesulfonate (0.7 g) are added thereto, and a mixture is stirred for 2 hours. A stirred mixture is phase-separated, washed three times with pure water (10 g), and then methylene chloride is evaporated to obtain a crude crystal. The crude crystal is purified by silica gel column chromatography (methylene chloride/methanol=90/10 (volume ratio)) to obtain {6-[3-(4-methylphenyl)-1-oxo-2-propenyl]-2-methoxynaphthalen-1-yl}diphenylsulfonium-nonafluorobutanesulfonate (0.9 g).

(120) ##STR00104##

Synthesis Example 59

Synthesis of {6-[3-(4-methylphenyl)-1,1-dimethoxy-2-propenyl]-2-methoxynaphthalen-1-yl}diphenylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 19)

(121) {6-[3-(4-Methylphenyl)-1,1-dimethoxy-2-propenyl]-2-methoxynaphthalen-1-yl}diphenylsulfonium-nonafluorobutanesulfonate (0.9 g) is obtained in the same procedure as Synthesis Example 4 except that {6-[3-(4-methylphenyl)-1-oxo-2-propenyl]-2-methoxynaphthalen-1-yl}diphenylsulfonium-nonafluorobutanesulfonate is used instead of dimethyl-[4-(4-phenylsulfanyl)benzoylphenyl]sulfonium-nonafluorobutanesulfonate.

(122) ##STR00105##
<Synthesis of Sulfonium Salt 20>

Synthesis Example 60

Synthesis of 2,3-dibromo-1-(6-methoxy-2-naphthalenyl)-3-(4-methylphenyl)-1-propanone

(123) 1-(6-Methoxy-2-naphthalenyl)-3-(4-methylphenyl)-2-propen-1-one (1.2 g) obtained in Synthesis Example 57 is dissolved in methylene chloride (9.6 g). Bromine (1.0 g) is dissolved in methylene chloride (2.0 g) to add dropwise thereto with ice cooling, and a mixture is stirred. After 2 hours, pure water (5 g) is added to a reaction solution, and a mixture is further stirred. A stirred mixture is phase-separated, an organic layer is washed twice with pure water (5 g), and then an organic solvent is evaporated to obtain 2,3-dibromo-1-(6-methoxy-2-naphthalenyl)-3-(4-methylphenyl)-1-propanone (1.8 g).

(124) ##STR00106##

Synthesis Example 61

Synthesis of 1-(6-methoxy-2-naphthalenyl)-3-(4-methylphenyl)-2-propyn-1-one

(125) 2,3-Dibromo-1-(6-methoxy-2-naphthalenyl)-3-(4-methylphenyl)-1-propanone (1.8 g) and diazabicycloundecene (0.8 g) is added to acetonitrile (14 g), and a mixture is stirred at room temperature. After 2 hours, potassium t-butoxide (1.6 g) is added thereto, and a mixture is further stirred. After 2 hours, pure water (36 g) is added to a reaction solution to precipitate a solid. The precipitated solid is filtered, washed with pure water (20 g), and then dried to obtain 1-(6-methoxy-2-naphthalenyl)-3-(4-methylphenyl)-2-propyn-1-one (1.0 g).

(126) ##STR00107##

Synthesis Example 62

Synthesis of {6-[3-(4-methylphenyl)-1-oxo-2-propynyl]-2-methoxynaphthalen-1-yl}diphenylsulfonium-nonafluorobutanesulfonate

(127) {6-[3-(4-Methylphenyl)-1-oxo-2-propynyl]-2-methoxynaphthalen-1-yl}diphenylsulfonium-nonafluorobutanesulfonate (0.8 g) is obtained in the same procedure as Synthesis Example 58 except that 1-(6-methoxy-2-naphthalenyl)-3-(4-methylphenyl)-2-propyn-1-one is used instead of 1-(6-methoxy-2-naphthalenyl)-3-(4-methylphenyl)-2-propen-1-one.

(128) ##STR00108##

Synthesis Example 63

Synthesis of {6-[3-(4-methylphenyl)-1,1-dimethoxy-2-propynyl]-2-methoxynaphthalen-1-yl}diphenylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 20)

(129) {6-[3-(4-Methylphenyl)-1,1-dimethoxy-2-propynyl]-2-methoxynaphthalen-1-yl}diphenylsulfonium-nonafluorobutanesulfonate (0.8 g) is obtained in the same procedure as Synthesis Example 4 except that {6-[3-(4-methylphenyl)-1-oxo-2-propynyl]-2-methoxynaphthalen-1-yl}diphenylsulfonium-nonafluorobutanesulfonate is used instead of dimethyl-[4-(4-phenylsulfanyl)benzoylphenyl]sulfonium-nonafluorobutanesulfonate.

(130) ##STR00109##
<Synthesis of Sulfonium Salt 21>

Synthesis Example 64

Synthesis of 4-phenylsulfanylbenzil

(131) 4-Phenylsulfanylbenzil (0.8 g) is obtained in the same procedure as Synthesis Example 2 except that 4-chlorobenzil (1 g) is used instead of 4-fluoro-4′-methylsulfanylbenzophenone.

(132) ##STR00110##

Synthesis Example 65

Synthesis of [4-(benzoylcarbonyl)phenyl]dimethylsulfonium-nonafluorobutanesulfonate

(133) 4-Phenylsulfanylbenzil (0.8 g), diphenyliodonium-nonafluorobutanesulfonate (1.6 g) and copper (II) acetate dihydrate (55 mg) are added to chlorobenzene (8.0 g), and a mixture is stirred at 80° C. After 2 hours, a reaction solution is cooled to 25° C., and pure water (5.0 g) is added thereto. A mixture is phase-separated, an organic layer is washed twice with pure water (5.0 g), and then an organic solvent is evaporated to obtain a crude crystal. The crude crystal is purified by silica gel column chromatography (methylene chloride/methanol=90/10 (volume ratio)) to obtain [4-(benzoylcarbonyl)phenyl]dimethylsulfonium-nonafluorobutanesulfonate (1.0 g).

(134) ##STR00111##

Synthesis Example 66

Synthesis of [4-(benzoyldimethoxymethyl)phenyl]dimethylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 21)

(135) [4-(Benzoyldimethoxymethyl)phenyl]dimethylsulfonium-nonafluorobutanesulfonate (0.9 g) is obtained in the same procedure as Synthesis Example 4 except that [4-(benzoylcarbonyl)phenyl]dimethylsulfonium-nonafluorobutanesulfonate is used instead of dimethyl-[4-(4-phenylsulfanyl) benzoylphenyl]sulfonium-nonafluorobutanesulfonate.

(136) ##STR00112##
<Synthesis of Sulfonium Salt 22>

Synthesis Example 67

Synthesis of 4-bromo-4′-(4-methoxyphenyl)benzophenone

(137) 4-Bromo-4′-(4-methoxyphenyl)benzophenone (3.1 g) is obtained in the same procedure as Synthesis Example 16 except that 4-bromobenzoyl chloride is used instead of 4-fluorobenzoyl chloride, 4-phenylanisole is used instead of 2,4-dimethoxybenzene, and as purification method, silica gel column chromatography (hexane/ethyl acetate=80/20 (volume ratio)) is performed instead of recrystallization with ethanol.

(138) ##STR00113##

Synthesis Example 68

Synthesis of 4-bromo-4′-(4-methoxyphenyl)benzophenone dimethyl acetal

(139) 4-Bromo-4′-(4-methoxyphenyl)benzophenone (3.0 g) is obtained in the same procedure as Synthesis Example 21 except that 4-bromo-4′-(4-methoxyphenyl)benzophenone is used instead of 4-bromo-4′-phenylsulfanylbenophenone.

(140) ##STR00114##

Synthesis Example 69

Synthesis of [4-(4′-methoxybiphenyl-4-carbonyl)phenyl]-diphenylsulfonium-nonafluorobutanesulfonate

(141) [4-(4′-Methoxybiphenyl-4-carbonyl)phenyl]-diphenylsulfonium-nonafluorobutanesulfonate (4.7 g) is obtained in the same procedure as Synthesis Example 22 except that 4-bromo-4′-(4-methoxyphenyl)benzophenone dimethyl acetal is used instead of 4-bromo-4′-phenylsulfanylbenzophenone dimethyl acetal and 10% by mass of aqueous solution of hydrochloric acid is used instead of 10% by mass of aqueous solution of ammonium chloride.

(142) ##STR00115##

Synthesis Example 70

Synthesis of [4-(4′-hydroxybiphenyl-4-carbonyl)phenyl]-diphenylsulfonium-nonafluorobutanesulfonate

(143) [4-(4′-Methoxybiphenyl-4-carbonyl)phenyl]-diphenylsulfonium-nonafluorobutanesulfonate (4.7 g) is obtained in the same procedure as Synthesis Example 22 except that 4-bromo-4′-(4-methoxyphenyl)benzophenone dimethyl acetal is used instead of 4-bromo-4′-phenylsulfanylbenzophenone dimethyl acetal and 10% by mass of aqueous solution of hydrochloric acid is used instead of 10% by mass of aqueous solution of ammonium chloride.

(144) [4-(4′-Methoxybiphenyl-4-carbonyl)phenyl]-diphenylsulfonium-nonafluorobutanesulfonate (4.0 g) is added to acetic acid (40 ml). 48% by mass of aqueous solution (10.2 g) of HBr is added dropwise thereto at 70° C. After dropwise addition, a mixture is stirred at 110° C. for 20 hours. Then, water (150 g) is added thereto, methylene chloride (40 g) is added thereto, and a mixture is stirred. A stirred mixture is phase-separated, washed three times with water, and then methylene chloride is evaporated to obtain a crude crystal. The crude crystal is purified by silica gel column chromatography (methylene chloride/methanol=90/10 (volume ratio)) to obtain [4-(4′-hydroxybiphenyl-4-carbonyl)phenyl]-diphenylsulfonium-nonafluorobutanesulfonate (2.4 g).

(145) ##STR00116##

Synthesis Example 71

Synthesis of {4-[(4′-hydroxybiphenyl-4-yl)dimethoxymethyl]-phenyl}-diphenylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 22)

(146) [4-(4′-Hydroxybiphenyl-4-carbonyl)phenyl]-diphenylsulfonium-nonafluorobutanesulfonate (1.0 g) obtained in Synthesis Example 70 is dissolved in methanol (2.5 g), trimethyl orthoformate (1.0 g) and concentrated sulfuric acid (4.0 mg) are added thereto, and a mixture is stirred at 60° C. for 2 hours. After stirring, triethylamine (0.5 g) is added thereto, a reaction solution is added to a mixed solution of methylene chloride (30 g) and pure water (10 g), a mixture is stirred for 10 minutes, and an organic layer is recovered. An obtained organic layer is washed three times with water, and then methylene chloride is evaporated to obtain {4-[(4′-hydroxybiphenyl-4-yl) dimethoxymethyl]-phenyl}-diphenylsulfonium-nonafluorobutanesulfonate (1.0 g).

(147) ##STR00117##
<Synthesis of Sulfonium Salt 23>

Synthesis Example 72

Synthesis of (6-bromo-naphthalen-2-yl)-(4-methoxyphenyl)methanone

(148) (6-Bromo-naphthalen-2-yl)-(4-methoxyphenyl)methanone (4.1 g) is obtained in the same procedure as Synthesis Example 16 except that 6-bromonaphthalenecarbonyl chloride is used instead of 4-fluorobenzoyl chloride and anisole is used instead of 2,4-dimethoxybenzene.

(149) ##STR00118##

Synthesis Example 73

Synthesis of (6-bromo-naphthalen-2-yl)-(4-methoxyphenyl)methanone dimethyl acetal

(150) (6-Bromo-naphthalen-2-yl)-(4-methoxyphenyl)methanone dimethyl acetal (3.0 g) is obtained in the same procedure as Synthesis Example 21 except that (6-bromo-naphthalen-2-yl)-(4-methoxyphenyl)methanone is used instead of 4-bromo-4′-phenylsulfanylbenzophenone.

(151) ##STR00119##

Synthesis Example 74

Synthesis of [6-(4-methoxybenzoyl)naphthalen-2-yl]diphenylsulfonium-nonafluorobutanesulfonate

(152) [6-(4-Methoxybenzoyl)naphthalen-2-yl]diphenylsulfonium-nonafluorobutanesulfonate (4.5 g) is obtained in the same procedure as Synthesis Example 69 except that (6-bromo-naphthalen-2-yl)-(4-methoxyphenyl)methanone dimethyl acetal is used instead of 4-bromo-4′-(4-methoxyphenyl)benzophenone dimethyl acetal.

(153) ##STR00120##

Synthesis Example 75

Synthesis of [6-(4-hydroxybenzoyl)naphthalen-2-yl]diphenylsulfonium-nonafluorobutanesulfonate

(154) [6-(4-Hydroxybenzoyl) naphthalen-2-yl]diphenylsulfonium-nonafluorobutanesulfonate (3.8 g) is obtained in the same procedure as Synthesis Example 70 except that [6-(4-methoxybenzoyl) naphthalen-2-yl]diphenylsulfonium-nonafluorobutanesulfonate is used instead of [4-(4 ′-methoxybiphenyl-4-carbonyl)phenyl-diphenylsulfonium-nonafluorobutanesulfonate.

(155) ##STR00121##

Synthesis Example 76

Synthesis of {6-[dimethoxy-(4-methoxyphenyl)methyl]naphthalen-2-yl}diphenylsulfonium-nonafluorobutanesulfonate (Sulfonium Salt 23)

(156) {6-[Dimethoxy-(4-methoxyphenyl)methyl]naphthalen-2-yl}diphenylsulfonium-nonafluorobutanesulfonate (3.6 g) is obtained in the same procedure as Synthesis Example 71 except that [6-(4-hydroxybenzoyl)naphthalen-2-yl]diphenylsulfonium-nonafluorobutanesulfonate is used instead of {4-[(4′-hydroxybiphenyl-4-yl)dimethoxymethyl]-phenyl}-diphenylsulfonium-nonafluorobutanesulfonate.

(157) ##STR00122##
<Synthesis of Polymer A>

Synthesis Example 50

Synthesis of Polymer A

(158) Polyhydroxystyrene (8.0 g) with weight-average molecular weight of 8000 and 35% by mass of aqueous solution (0.010 g) of hydrochloric acid are dissolved in dehydrated dioxane (28 g). Cyclohexyl vinyl ether (2.73 g) is dissolved in dehydrated dioxane (2.80 g), and a mixture is added dropwise to the solution of polyhydroxystyrene over 30 minutes. After dropwise addition, a mixture is set to 40° C., and stirred for 2 hours. After stirring, a mixture is cooled, and then dimethylaminopyridine (0.014 g) is added thereto. Thereafter, an obtained solution is added dropwise to pure water (260 g) to precipitate a polymer. The precipitated polymer is separated by filtration under reduced pressure to obtain a solid, the solid is washed twice with pure water (300 g), and then dried under vacuum to obtain Polymer A (9.2 g), represented below, as a white solid. A monomer ratio of unit of the polymer in the present invention is not limited to the below.

(159) ##STR00123##
<Synthesis of Polymer C>

Synthesis Example 51

Synthesis of Polymer B

(160) Acetoxystyrene (7.0 g), t-butyl methacrylate (3.1 g), butyl mercaptan (0.022 g) and dimethyl-2,2′-azobis(2-methylpropionate) (AIBN) (0.40 g) are dissolved in tetrahydrofuran (THF) (35 g), and a mixture is deoxygenated. A deoxygenated mixture is added dropwise over 4 hours to THF (20 g) which is set to reflux temperature under nitrogen flow in advance. After dropwise addition, a mixture is stirred for 2 hours, and then cooled to room temperature. A cooled mixture is added dropwise to a mixed solvent of hexane (149 g) and THF (12 g) to precipitate a polymer. The precipitated polymer is separated by filtration under reduced pressure to obtain a solid, the solid is washed with hexane (52 g), and then dried under vacuum to obtain Polymer B (10.3 g), represented by the following formula, as a white solid. A weight-average molecular weight calculated by polystyrene conversion using a gel permeation chromatography is 9200. A monomer ratio of unit of the polymer in the present invention is not limited to the below.

(161) ##STR00124##

Synthesis Example 52

Synthesis of Polymer C

(162) Polymer B (6.0 g), triethylamine (6.0 g), methanol (6.0 g) and pure water (1.5 g) are dissolved in propylene glycol monomethyl ether (30 g), and a mixture is stirred at reflux temperature for 6 hours. Then, a mixture is cooled to 25° C., and an obtained solution is added dropwise to a mixed liquid of acetone (30 g) and pure water (30 g) to precipitate a polymer. The precipitated polymer is separated by filtration under reduced pressure to obtain a solid, the solid is washed twice with pure water (30 g), and then dried under vacuum to obtain Polymer C (4.3 g), represented by the following formula, as a white solid. A weight-average molecular weight calculated by polystyrene conversion using a gel permeation chromatography is 9100. A monomer ratio of unit of the polymer in the present invention is not limited to the below.

(163) ##STR00125##
<Synthesis of Polymer D>

Synthesis Example 53

Synthesis of Polymer D

(164) α-Methacryloxy-γ-butyrolactone (5.0 g), 2-methyladamantane-2-methacrylate (6.0 g), 3-hydroxyadamantane-1-methacrylate (4.3 g) and dimethyl-2,2′-azobis(2-methylpropionate) (0.51 g) are dissolved in propylene glycol-1-monomethyl ether acetate (PGMEA) (26 g), and a mixture is deoxygenated. A deoxygenated mixture is added dropwise over 4 hours to PGMEA (7.5 g) which is heated to 85° C. in advance. A mixture is stirred for 2 hours, and then cooled. After cooling, a mixture is added dropwise to hexane (180 g) to reprecipitate. A reprecipitated solid is filtered, dispersion-washed with hexane (70 g), filtered again, and then dried under vacuum to obtain Polymer D (8.5 g), represented by the following formula, as a compound to react with an acid. A monomer ratio of unit of the polymer in the present invention is not limited to the below.

(165) ##STR00126##
<Synthesis of Polymer F>

Synthesis Example 54

Synthesis of Polymer E

(166) Polymer E (10.1 g), represented by the following formula, is obtained in the same procedure as Synthesis Example 51 except that p-t-butoxystyrene is used instead of t-butyl methacrylate. A monomer ratio of unit of the polymer in the present invention is not limited to the below.

(167) ##STR00127##

Synthesis Example 55

Synthesis of Polymer F

(168) Polymer F (4.1 g), represented by the following formula, is obtained in the same procedure as Synthesis Example 52 except that Polymer E is used instead of Polymer B. A monomer ratio of unit of the polymer in the present invention is not limited to the below.

(169) ##STR00128##
<Synthesis of Polymer G>

Synthesis Example 56

Synthesis of Polymer G

(170) Polymer G (8.0 g), represented by the following formula, is obtained in the same procedure as Synthesis Example 53 except that 5-methacryloyloxynorbornane 2,6-lactone (5.5 g), 4-(1-ethoxyethoxy)phenyl methacrylate (6.2 g) and 4-hydroxyphenyl methacrylate (4.4 g) are used as monomers. A monomer ratio of unit of the polymer in the present invention is not limited to the below.

(171) ##STR00129##
<Synthesis of Polymer I>

Synthesis Example 57

Synthesis of Polymer H

(172) Polymer H (10.5 g), represented by the following formula, is obtained in the same procedure as Synthesis Example 51 except that 1-acetoxy-4-vinylnaphthalene is used instead of acetoxystyrene and 1-(2-tetrahydropyranyloxy)-4-vinylnaphthalene is used instead of t-butyl methacrylate. A monomer ratio of unit of the polymer in the present invention is not limited to the below.

(173) ##STR00130##

Synthesis Example 58

Synthesis of Polymer I

(174) Polymer I (4.3 g), represented by the following formula, is obtained in the same procedure as Synthesis Example 52 except that Polymer H is used instead of Polymer B. A ratio of monomer unit of the polymer is not limited to the below.

(175) ##STR00131##
<Synthesis of Polymer J>

Synthesis Example 59

Synthesis of Polymer J

(176) Polymer J (8.0 g), represented by the following formula, is obtained in the same procedure as Synthesis Example 53 except that 2-methacryloyloxy-1,3-propanesultone is used instead of α-methacryloxy-γ-butyrolactone. A monomer ratio of unit of the polymer in the present invention is not limited to the below.

(177) ##STR00132##
<Synthesis of Polymer K>

Synthesis Example 60

Synthesis of Polymer K

(178) Polymer K (8.2 g), represented by the following formula, is obtained in the same procedure as Synthesis Example 53 except that 2-methacryloyloxy-1,3-propanesultone is used instead of α-methacryloxy-γ-butyrolactone and 1-ethoxyethyl methacrylate is used instead of 2-methyladamantane-2-methacrylate. A monomer ratio of unit of the polymer in the present invention is not limited to the below.

(179) ##STR00133##
<Synthesis of Polymer L>

Synthesis Example 61

Synthesis of Polymer L

(180) Polymer L (8.0 g), represented by the following formula, is obtained in the same procedure as Synthesis Example 53 except that 5-methacryloyloxynorbornane 2,6-sultone (7.2 g), 2-(1-ethoxyethoxy)-6-vinylnaphthalene (5.9 g) and 2-hydroxy-6-vinylnaphthalene (3.0 g) are used as polymers. A monomer ratio of unit of the polymer in the present invention is not limited to the below.

(181) ##STR00134##
<Synthesis of Polymer M>

Synthesis Example 62

Synthesis of Polymer M

(182) Polymer M (7.8 g), represented by the following formula, is obtained in the same procedure as Synthesis Example 53 except that Sulfonium Salt 16 (4.7 g) obtained in Synthesis Example 49, 5-methacryloyloxynorbornane 2,6-lactone (3.9 g), 4-(1-ethoxyethoxy)phenyl methacrylate (4.2 g) and 4-hydroxyphenyl methacrylate (3.2 g) are used as polymers. A monomer ratio of unit of the polymer in the present invention is not limited to the below.

(183) ##STR00135##

Examples 1 to 32 and Comparative Examples 1 to 6

(184) <Evaluation of Electron Beam Sensitivity 1>

(185) Each sample was prepared as follows. To cyclohexanone (3000 mg), any one of resin (500 mg) selected from Polymers A, C and D, each compound (0.036 mmol) appropriately selected solely or plurally from a photoacid generator (PAG) and a sensitizer compound, and an acid-diffusion controller (0.0012 mmol) were added in the ratio, to prepare Sample.

(186) As the photoacid generator (PAG), Sulfonium Salts 1 to 23, Sulfonium Salt 24 represented below and Iodonium Salts 1 to 2 were used. As the sensitizer compound, Sensitizer Compound 1 and Comparative Sensitizer Compounds 1′ to 2′ represented below were used.

(187) Sensitizer Compound 1 was synthesized as follows. 4-Methylsulfanyl-4′-phenylsulfanylbenzophenone (5.0 g) obtained in Synthesis Example 2, sulfuric acid (47 mg), and trimethyl orthoformate (13.5 g) are dissolved in methanol (12.5 g), and a mixture is stirred at reflux temperature for 3 hours. Then, a mixture is cooled to room temperature, 5% by mass of aqueous solution (50 g) of sodium hydrogen carbonate is added thereto, a mixture is further stirred for 10 minutes, and a precipitated crystal is filtrated. The crystal is recovered, re-dissolved in ethyl acetate (50 g), and a solution is washed with water. Thereafter, ethyl acetate is evaporated to obtain 4-methylsulfanyl-4′-phenylsulfanylbenzophenone dimethyl acetal (3.1 g).

(188) ##STR00136##

(189) Evaluation of electron beam sensitivity is performed as follows. The resist composition sample 1 is spin-coated on a silicon wafer modified with hexamethylenedisilazane in advance. A spin-coated sample is prebaked on a hot plate at 110° C. for 1 minute to obtain a substrate on which a coating film having a thickness of 200 nm forms. To the coating film on the substrate, a line and space pattern of 200 nm is drawn by an electron beam of 30 keV using an electron beam lithography system. After irradiation with the electron beam, the entire surface of the substrate is exposed with exposure dose of 500 mJ/cm.sup.2 using a UV exposure system, and then the substrate was heated on a hot plate at 110° C. for 1 minute. The substrate is developed with a developing solution, product name: NMD-3, 2.38% by mass of aqueous solution of tetramethylammonium hydroxide, manufactured by Tokyo Ohka Kogyo Co., Ltd., for 1 minute, and then rinsed with pure water to obtain a line and space pattern of 200 nm. An irradiation dose of the electron beam at this time is defined as E.sub.size [μC/cm.sup.2], and a sensitivity to the irradiation with the electron beam is evaluated. In addition, the obtained fine pattern is observed to measure LWR. The sensitivity evaluation and LWR measurement are also performed on the other samples in the same procedure as above. The sample compositions and results are described in Tables 1 to 3.

(190) In Table 1, sensitivity and LWR of each sample of Examples 1 to 17 and Comparative Example 2 were calculated as relative values with sensitivity of sample of Comparative Sample 1 being 100 and with LWR of that being 1, and Sulfonium Salt 24 and Comparative Sensitizer Compound 1′ being added to Comparative Sample 1. The smaller a value of sensitivity and LWR, the more effective.

(191) In Table 2, evaluation results of samples of Examples 18 to 24 and Comparative Example 4 were calculated as relative values with sensitivity of Comparative Example 3 being 100 and with LWR of that being 1.

(192) In Table 3, evaluation results of samples of Examples 25 to 32 and Comparative Example 6 were calculated as relative value, with sensitivity of Comparative Example 5 being 100 and with LWR of that being 1.

(193) TABLE-US-00001 TABLE 1 Sensitivity Resist Composition (E.sub.size) LWR Copolymer Photoacid Generator Sensitizer Compound (Rel.) (Rel.) Example 1 Polymer A Sulfonium Salt 1 Sulfonium Salt 24 — 75 0.95 Example 2 Polymer A Sulfonium Salt 7 Sulfonium Salt 24 — 60 0.95 Example 3 Polymer A Sulfonium Salt 9 Sulfonium Salt 24 — 55 0.95 Example 4 Polymer A Sulfonium Salt 11 Sulfonium Salt 24 — 70 0.98 Example 5 Polymer A Sulfonium Salt 12 Sulfonium Salt 24 — 53 0.98 Example 6 Polymer A Iodonium Salt 1 Sulfonium Salt 24 — 53 0.98 Example 7 Polymer A Sulfonium Salt 1 — — 85 0.93 Example 8 Polymer A Sulfonium Salt 7 — — 70 0.93 Example 9 Polymer A Sulfonium Salt 9 — — 65 0.93 Example 10 Polymer A Sulfonium Salt 11 — — 80 0.95 Example 11 Polymer A Sulfonium Salt 12 — — 60 0.95 Example 12 Polymer A Iodonium Salt 1 — — 63 0.98 Example 13 Polymer A Sulfonium Salt 9 — Sensitizer Compound 1 58 0.95 Example 14 Polymer A Iodonium Salt 1 — Sensitizer Compound 1 55 0.99 Example 15 Polymer A Sulfonium Salt 17 — — 68 0.93 Example 16 Polymer A Sulfonium Salt 22 — — 86 0.97 Example 17 Polymer A Sulfonium Salt 23 — — 62 0.93 Comparative Polymer A — Sulfonium Salt 24 Comparative Sensitizer 100 1 Example 1 Compound 1′ Comparative Polymer A — Sulfonium Salt 24 Comparative Sensitizer 140 1 Example 2 Compound 2′

(194) TABLE-US-00002 TABLE 2 Sensitivity Resist Composition (E.sub.size) LWR Copolymer Photoacid Generator Sensitizer Compound (Rel.) (Rel.) Example 18 Polymer C Sulfonium Salt 1 Sulfonium Salt 24 — 75 0.95 Example 19 Polymer C Sulfonium Salt 2 Sulfonium Salt 24 — 80 0.95 Example 20 Polymer C Sulfonium Salt 3 Sulfonium Salt 24 — 78 0.88 Example 21 Polymer C Sulfonium Salt 9 — — 65 0.93 Example 22 Polymer C Sulfonium Salt 13 — — 70 0.95 Example 23 Polymer C Sulfonium Salt 18 — — 63 0.98 Example 24 Polymer C Sulfonium Salt 20 — — 73 0.97 Comparative Polymer C — Sulfonium Salt 24 Comparative Sensitizer 100 1 Example 3 Compound 1′

(195) TABLE-US-00003 TABLE 3 Sensitivity Resist Composition (E.sub.size) LWR Copolymer Photoacid Generator Sensitizer Compound (Rel.) (Rel.) Example 25 Polymer D Sulfonium Salt 1 Sulfonium Salt 24 — 75 0.95 Example 26 Polymer D Sulfonium Salt 6 Sulfonium Salt 24 — 83 0.95 Example 27 Polymer D Sulfonium Salt 8 — — 90 0.93 Example 28 Polymer D Sulfonium Salt 9 — — 65 0.93 Example 29 Polymer D Sulfonium Salt 14 — — 60 0.98 Example 30 Polymer D Sulfonium Salt 19 — — 63 0.95 Example 31 Polymer D Sulfonium Salt 21 — — 62 0.98 Example 32 Polymer D Sulfonium Salt 23 — — 58 0.98 Comparative Polymer D — Sulfonium Salt 24 Comparative Sensitizer 100 1 Example 5 Compound 1′ Comparative Polymer D — Sulfonium Salt 24 Comparative Sensitizer 140 1 Example 6 Compound 2′

(196) It is found that: the sensitivities of Examples 1 to 17, which are samples containing onium salts according to some embodiments of the present invention, are higher than those of Comparative Examples 1 and 2; the sensitivities of Examples 18 to 24 are higher than those of Comparative Examples 3 and 4; and the sensitivities of Examples 25 to 32 are higher than those of Comparative Examples 5 and 6, respectively.

(197) The reason might be as follows. Deprotection of the acetal group occurs in the onium salt according to some embodiments of the present invention by an acid generated in the resist film by irradiation with the electron beam as the first active energy ray, and the onium salt becomes a ketone derivative. Since the ketone derivative has absorption in UV as the second active energy ray, it can directly generate an acid by excitation by irradiation with UV. On the other hand, in Comparative Examples 1 to 6, a reaction involving electron transfer such as photoinduced electron transfer reaction like photosensitization is utilized. That is, it is assumed that since a sensitization reaction between molecules is utilized, the sensitivity is not good and decreases compared with the case when the acid is directly generated by excitation.

(198) Furthermore, by using the onium salt according to some embodiments of the present invention, since acid diffusion involving electron transfer does not occur in the acid generation by irradiation with the second active energy ray, LWR can be suppressed as compared with Comparative Examples 1 to 6 utilizing the sensitization reaction between molecules.

(199) The reason why the sensitivities of Example 13 and Example 14 become higher than that of Example 9 and Example 12 respectively might be as follows. In Example 13 and Example 14, at the time of irradiation with the second active energy ray, an acid is generated by the excitation of the ketone derivative having the absorption in the second active energy ray, and then an acid is generated by photosensitization occurring between the photosensitizer derived from the Sensitizing Compound 1 and Sulfonium Salt 9 or Iodonium Salt 1 having a high electron accepting property at the time of irradiation with the first active energy ray.

Examples 1, 33 to 39 and Comparative Examples 1 and 7 to 8

(200) <Electron Beam Sensitivity Evaluation 2>

(201) A line and space pattern of 200 nm is obtained by the same operation as in the above example <Electron Beam Sensitivity Evaluation 1>, except that PEB is performed for 30 seconds on a hot plate at 60 ° C. after the electron beam irradiation. An irradiation dose of the electron beam at this time is defined as E.sub.size [μC/cm.sup.2], and a sensitivity when PEB is performed after the irradiation with the electron beam is evaluated. In addition, the obtained pattern is observed to measure LWR. The sample compositions and results are described in Table 4. Sensitivity and LWR of each sample (Examples 33 to 39 and Comparative Example 8) were calculated as relative values with sensitivity of sample of Comparative Sample 7 being 100 and with LWR of that being 1, and Sulfonium Salt 24 and Comparative Sensitizer Compound 1′ being added to Comparative Sample 7. In order to compare the effects of PEB, the sensitivity and LWR of the samples of Example 1 and Comparative Example 1 were calculated as relative values with the ones of Comparative Example 7, and evaluated. That is, in Table 4, in order to compare the effects of PEB, the evaluation of the Example 1, as evaluation of the sample in which Sulfonium Salt 1 and Sulfonium Salt 24 are added without PEB; and the evaluation of the Comparative Example 1 as evaluation of the sample in which Sulfonium Salt 24 and Comparative Sensitizing Compound 1′ are added without PEB; are described.

(202) The smaller a value of sensitivity and LWR, the more effective.

(203) TABLE-US-00004 TABLE 4 Sensitivity Resist Composition (E.sub.size) LWR Copolymer Photoacid Generator Sensitizer Compound (Rel.) (Rel.) Example 33 Polymer A Sulfonium Salt 1 Sulfonium Salt 24 — 75 0.95 Example 34 Polymer A Sulfonium Salt 1 — — 85 0.93 Example 35 Polymer A Sulfonium Salt 7 — — 70 0.93 Example 36 Polymer A Sulfonium Salt 9 — — 65 0.93 Example 37 Polymer A Sulfonium Salt 12 — — 60 0.95 Example 38 Polymer A Sulfonium Salt 1 — — 63 0.98 Example 39 Polymer A Sulfonium Salt 7 — — 78 0.90 Comparative Polymer A — Sulfonium Salt 24 Comparative Sensitizer 100 1 Example 7 Compound 1′ Comparative Polymer A — Sulfonium Salt 24 Comparative Sensitizer 140 1 Example 8 Compound 2′ Example 1 Polymer A Sulfonium Salt 1 Sulfonium Salt 24 — 90 0.93 Comparative Polymer A — Sulfonium Salt 24 Comparative Sensitizer 120 0.98 Example 1 Compound 1′

(204) Even when PEB is performed at 60 ° C. after the irradiation with the electron beam in the pattern forming step, in Examples 33 to 39, which are samples containing the onium salts according to some embodiments of the present invention, the sensitivity is higher and the LWR can be suppressed like the Examples 1 to 32, more than that in Comparative Examples 7 and 8 utilizing the sensitization reaction between molecules. In addition, comparing Example 33, Example 1 and Comparative Example 1, it is assumed that since in Example 33, PEB after the irradiation with the electron beam diffuses the acid generated by the electron beam as the first active energy ray, more ketone derivatives having absorption in the second active energy ray are generated in the resist film, the sensitivity is improved as compared with Example 1 and Comparative Example 1, which do not have PEB step after the irradiation with the electron beam.

(205) In Example 33, the LWR is somewhat deteriorated as compared with Example 1 due to the effect of acid diffusion by PEB, but since the acid diffusion involving electron transfer does not occur in the acid generation by the irradiation with the second energy ray, the LWR can be suppressed as compared with Comparative Example 1 in which the sensitization reaction is utilized.

(206) The polymer A has a higher proportion, than the polymer C, of hydroxystyrene and its derivative, which having a lower ionization potential, than the polymer C, and the polymer A has slightly higher secondary electron generation efficiency than the polymer C, so that the acid generation efficiency is improved by the irradiation with the electron beam as the first active energy ray and activation energy of a reactive group to an acid is lower, and the deprotection reaction progresses efficiently. Therefore, comparing Example 35 and Example 39, the sensitivity of Example 35 is higher than that of Example 39.

Examples 40 to 44 and Comparative Example 9

(207) <Electron Beam Sensitivity Evaluation 3>

(208) A line and space pattern of 200 nm is obtained by the same operation as in the above example <Electron Beam Sensitivity Evaluation 2>. An irradiation dose of the electron beam at this time is defined as E.sub.size [μC/cm.sup.2], and a sensitivity when PEB is performed by the irradiation with the electron beam is evaluated. In addition, the obtained fine pattern is observed to measure LWR. The sample compositions and results are described in Table 5. Sensitivity and LWR of each sample (Examples 40 to 44) were calculated as relative values with sensitivity of sample of Comparative Sample 9 being 100 and with LWR of that being 1, and Sulfonium Salt 24 and Comparative Sensitizer Compound 1′ being added to Comparative Sample 9.

(209) The smaller a value of sensitivity and LWR, the more effective.

(210) TABLE-US-00005 TABLE 5 Sensitivity Resist Composition (E.sub.size) LWR Copolymer Photoacid Generator Sensitizer Compound (Rel.) (Rel.) Example 40 Polymer D Sulfonium Salt 7 — — 70 0.90 Example 41 Polymer J Sulfonium Salt 7 — — 65 0.93 Example 42 Polymer K Sulfonium Salt 7 — — 60 0.95 Example 43 Polymer G Sulfonium Salt 7 — — 63 0.98 Example 44 Polymer M — — — 58 0.85 Comparative Polymer D — Sulfonium Salt 24 Comparative Sensitizer 100 1 Example 9 Compound 1′

(211) In Examples 40 to 43, which are samples containing the onium salts according to some embodiments of the present invention, the sensivity is higher and the LWR can be suppressed as in Examples 1 to 32 more than Comparative Example 9 utilizing a sensitization reaction between molecules. It is found that even when the onium salt of the present invention is contained in the polymer as in Example 44, the same function as the sample to which the onium salt is added can be obtained, so that the sensitivity is higher than Comparative Example 9 and the LWR can be suppressed.

(212) Comparing Examples 40 to 42, it is assumed that by using a polymer containing a sultone compound as in Examples 41 and 42, an acid generated by decomposition of the sultone compound after irradiation with the electron beam as the first active energy ray contributes to deprotection reaction of the acetal of the onium salt according to some embodiments of the present invention. As a result, more ketone derivatives having absorption in the second active energy ray can be produced, so that the sensitivities of Examples 41 and 42 are higher than those of Example 40. Further, in Example 42, it is assumed that since the acid reactive compound is an acid dissociable protecting group having low activation energy, the acid generated by the decomposition of the sultone compound after the irradiation with the electron beam as the first active energy ray also contributes to polarity conversion by reaction with the acid reactive compound. Then, the solubility of the resin in the developing solution changes more. Therefore, the sensitivity of Examples 42 is higher than those of Example 41.

(213) Comparing Examples 43 and 44, in Example 44, it is assumed since an anion moiety of the onium salt according to the present invention is copolymerized with a polymer, an acid generated upon irradiation with the electron beam as the first active energy ray and the second active energy ray hardly diffuse, and the LWR can be suppressed more than Example 43.

INDUSTRIAL APPLICABILITY

(214) According to some embodiments of the present invention, a resin composition containing an onium salt can be provided. A structure of the onium salt changes to a ketone derivative by an active species generated by irradiation with a first active energy ray such as an electron beam or an extreme ultraviolet, and the ketone derivative generates an active species by irradiation with a second active energy ray.

(215) By using the above resin composition, a resist composition having high sensitivity and excellent pattern characteristics such as LWR can be obtained.