Method for producing purified triarylsulfonium salts

Abstract

The present invention provides a photoacid generator from which metal ions, which are impurities, have been sufficiently removed. [Solution] The present invention provides a method for producing purified triarylsulfonium salt, comprising a processing step of contacting a solution (A) containing a triarylsulfonium salt with a resin (B) having an aminophosphate group, wherein the solution (A) containing the triarylsulfonium salt is either a post-reaction solution (A1) obtained after a dehydration condensation reaction between a diphenyl sulfoxide compound and a (substituted) benzene, or a post-reaction solution (A2) obtained after a Grignard reaction using a diphenyl sulfoxide compound and a (substituted) phenylmagnesium halide.

Description

Technical Field

[0001] The present invention relates to a method for producing a purified triarylsulfonium salt.

Background Art

[0002] Production of electronic components and formation of semiconductor elements are carried out by EUV and EB lithography using a photoacid generator such as triphenylsulfonium salt. In order to cope with circuit miniaturization, triphenylsulfonium salts in which a hydrogen atom on a phenyl group is substituted with a specific substituent (Patent Documents 1 to 3) are known as photoacid generators having high sensitivity to EUV, EB, X-rays and the like.

[0003] However, these photoacid generators have insufficient adaptability to higher resolution, for example, impurities such as metal ions are not sufficiently removed, which may cause defects in a part of miniaturized circuits.

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problem to be Solved by the Invention

[0005] An object of the present invention is to provide a triarylsulfonium salt from which metal ions have been sufficiently removed.

Means for Solving the Problem

[0006] The inventors, after diligent research, have discovered the present invention. Specifically, the present invention is a method for producing a purified triarylsulfonium salt, comprising a processing step of contacting a solution (A) containing a triarylsulfonium salt with a resin (B) having an aminophosphate group. [Effects of the Invention]

[0007] The present invention provides a method for producing purified triarylsulfonium salts from which impurities such as metal ions have been sufficiently removed. [Modes for carrying out the invention]

[0008] The present invention relates to a method for producing a purified triarylsulfonium salt, comprising a processing step of contacting a solution (A) containing a triarylsulfonium salt with a resin (B) having an aminophosphate group. Furthermore, purified triarylsulfonium salt refers to a triarylsulfonium salt from which impurities have been removed by a process in which impurities are removed from the triarylsulfonium salt obtained by a reaction or other means by contacting it with a resin (B) having an aminophosphate group.

[0009] The triarylsulfonium salt contained in the solution (A) is not particularly limited, but for example, triphenylsulfonium salt, diphenyl-(4-phenylthio)phenylsulfonium salt, diphenyl(4-methylphenyl)sulfonium salt, diphenyl-2,4,6-trimethylphenylsulfonium salt, and diphenyl(4-hydroxyphenyl)sulfonium salt can be preferably used.

[0010] The anion of the triarylsulfonium salt contained in the solution (A) is not particularly limited, but examples include fluorinated alkyl sulfonates such as methanesulfonate, trifluoromethanesulfonate, and nonafluorobutanesulfonate; sulfonate ions such as camphor sulfonate and p-toluenesulfonate ions; phosphate ions such as hexafluorophosphate ions; borate ions such as tetrafluoroborate ions; and antimonate ions such as hexafluoroantimonate ions. Of these, triarylsulfonium salts with a fluorinated alkyl sulfonate anion can be preferably used.

[0011] The solution (A) containing the triarylsulfonium salt in the processing step can be the post-reaction solution obtained after carrying out a known reaction to obtain the triarylsulfonium salt. Known reactions for obtaining triarylsulfonium salts include the dehydration condensation reaction of a diphenyl sulfoxide compound with a (substituted) benzene, and the Grignard reaction using a diphenyl sulfoxide compound with a (substituted) phenylmagnesium halide. Examples of halogen atoms in the (substituted) phenylmagnesium halide include chlorine, bromine, and iodine. Alternatively, a method involving the condensation of diphenyliodonium salt and diphenyl sulfide using a catalyst such as copper acetate can also be used. Furthermore, as the solution (A) containing the triarylsulfonium salt, a post-reaction solution obtained after carrying out a salt exchange reaction of the counterions of the triarylsulfonium salt following the known reaction described above can also be used.

[0012] Note that (substituted) benzene refers to benzene or substituted benzene. The substituted benzene is a compound in which a hydrogen atom of the benzene ring is replaced by another atom or group of atoms, and examples include toluene, xylene, and anisole. (Substitutive) phenyl means phenyl or substituted phenyl. The substituted phenyl is a compound in which a hydrogen atom of a phenyl group is replaced by another atom or group of atoms.

[0013] Examples of substituted phenylmagnesium halides include alkylphenylmagnesium halides, haloalkylphenylmagnesium halides, and alkoxyphenylmagnesium halides. The alkyl group of the alkylphenylmagnesium halide is preferably an alkyl group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. Examples of the alkylphenylmagnesium halide include methylphenylmagnesium halide and ethylphenylmagnesium halide. The alkyl group of the haloalkylphenylmagnesium halide is preferably an alkyl group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms. Examples of the aforementioned haloalkylphenylmagnesium halides include trifluoromethylphenylmagnesium halide and trifluoroethylphenylmagnesium halide. Examples of the alkoxyphenylmagnesium halide include methoxyphenylmagnesium halide.

[0014] As the solution (A) containing the triarylsulfonium salt used in the processing step, the post-reaction solution obtained after the dehydration condensation reaction between the diphenyl sulfoxide compound and (substituted) benzene [hereinafter referred to as post-reaction solution (A1)] is preferred.

[0015] As the solution (A) containing the triarylsulfonium salt used in the processing step, the post-reaction solution obtained after carrying out a Grignard reaction using a diphenyl sulfoxide compound and (substituted) phenylmagnesium halide [hereinafter referred to as post-reaction solution (A2)] is also preferred.

[0016] The present invention may further include a pretreatment step of mixing the solution (A) containing the triarylsulfonium salt with an acidic aqueous solution. Carrying out the pretreatment step is preferable because it facilitates the removal of impurities in the treatment step.

[0017] The acidic aqueous solution used in the pretreatment step is preferably an aqueous solution containing at least one Brønsted acid selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, phosphoric acid, and citric acid. The acid concentration of the acidic aqueous solution used in the pretreatment step is preferably 0.1 to 5% by weight based on the total weight of the acidic aqueous solution. The acidic aqueous solution preferably has a pH of 0 to 3.0 at 20°C. The pH of the acidic aqueous solution is measured in accordance with JIS Z8802 "Methods for pH measurement" using the temperature-controlled acidic aqueous solution itself adjusted to 20°C as a sample.

[0018] Mixing of the solution (A) containing the triarylsulfonium salt and the acidic aqueous solution can be carried out by mixing the solution (A) containing the triarylsulfonium salt and the acidic aqueous solution using a known liquid mixing apparatus. As the liquid mixing apparatus, a mixing vessel equipped with a stirrer, an in-line mixer, and the like can be preferably used.

[0019] Mixing of the solution (A) containing the triarylsulfonium salt and the acidic aqueous solution is preferably carried out at 10 to 40°C, and the mixing time of the solution (A) containing the triarylsulfonium salt and the acidic aqueous solution is preferably 0.5 to 1 hour.

[0020] After mixing the solution (A) containing the triarylsulfonium salt and the acidic aqueous solution, it is preferable to carry out a step of separating into a pretreated solution (AZ) containing the triarylsulfonium salt and an aqueous phase, that is, a liquid separation step. The liquid separation step can be carried out by a known method such as allowing the mixture to stand to separate into an organic solvent phase containing the triarylsulfonium salt and an aqueous phase.

[0021] At the end of the step of mixing the solution (A) containing the triarylsulfonium salt with the acidic aqueous solution, it is preferable that the amounts of sodium ions, potassium ions, and calcium ions in the pre-treated solution (AZ) containing the triarylsulfonium salt separated after mixing, or in the organic solvent phase containing the triarylsulfonium salt obtained after a liquid-liquid extraction step if necessary, are 5 ppb or less each, based on the weight of the sulfonium salt. The mixing of the solution (A) containing the triarylsulfonium salt with the acidic aqueous solution, and the separation step performed as needed, can be repeated until the endpoint is reached.

[0022] The process may include a pretreatment step of mixing a solution (A) containing the triarylsulfonium salt with an acidic aqueous solution, and a processing step of contacting the pretreated solution (AZ) obtained after the pretreatment step with a resin (B) having an aminophosphate group. Preferably, the post-reaction solution (AZ) is a pre-treated solution obtained after a pre-treatment step of mixing the post-reaction solution (A1) with an acidic aqueous solution [hereinafter referred to as pre-treated solution (AZ1)], and a pre-treated solution obtained after a pre-treatment step of mixing the post-reaction solution (A2) with an acidic aqueous solution [hereinafter referred to as pre-treated solution (AZ2)].

[0023] The processing step in the present invention is to bring a pre-treated solution (AZ) obtained after performing a pre-treatment step of mixing a solution (A) containing a triarylsulfonium salt with an acidic aqueous solution [hereinafter also referred to as the contacted liquid] into contact with a resin (B) having aminophosphate groups. Preferably, the liquid to be in contact with is the post-reaction solution (A1), the post-reaction solution (A2), the pre-treated solution (AZ1), and the pre-treated solution (AZ2). The aminophosphate groups of the resin (B) are coordinating groups that can form chelate bonds with metal ions, and can adsorb and detach metal ions from a solution (A) containing a sulfonium salt having a triphenylsulfonium skeleton. The resin (B) having aminophosphate groups is preferably in granular or fibrous form from the viewpoint of processing efficiency.

[0024] Examples of resins having an aminophosphate group (B) include resins having an aminophosphate group and resins having an aminomethylphosphate group. Examples of resins having the aforementioned aminophosphate group include S950 (manufactured by Purolite Co., Ltd.). Examples of resins having the aminomethyl phosphate group include OLLITE® DS-21 (manufactured by Organo Corporation) and AMBERCEP® IRC747UPS (manufactured by DuPont). As for the resin (B) having aminophosphate groups, from the viewpoint of highly accurate removal of metal ions from the solution (A) containing the triarylsulfonium salt, a resin having aminomethylphosphate groups is preferred.

[0025] The process of bringing the liquid to be contacted with the resin (B) having aminophosphate groups includes methods such as adding the resin (B) having aminophosphate groups to the liquid to be contacted and mixing them, and passing the liquid to be contacted through a cylindrical column containing the resin (B) having aminophosphate groups.

[0026] The temperature of the liquid to be contacted with the resin (B) having aminophosphate groups is preferably 10 to 40°C.

[0027] In the processing step of the present invention, the liquid to be contacted may be diluted with an organic solvent before being brought into contact with the resin (B) having aminophosphate groups. When diluting and bringing into contact with the resin (B) having aminophosphate groups, it is preferable to adjust the amount of organic solvent so that the viscosity of the diluted solution is 100 mPa·s or less.

[0028] In the step of bringing a liquid to be contacted with a resin (B) having aminophosphate groups, when the resin (B) having aminophosphate groups is added to the liquid to be contacted and mixed, the weight of the resin (B) having aminophosphate groups can be adjusted according to the weight of the liquid to be treated, preferably 5 to 20% by weight relative to the weight of the liquid to be contacted, and more preferably 10 to 15% by weight. The mixing time between the liquid to be contacted and the resin (B) having aminophosphate groups is preferably 1 to 3 hours, and more preferably 1 to 2 hours.

[0029] In the step of bringing a liquid to be contacted with a resin (B) having aminophosphate groups, when the resin (B) having aminophosphate groups is added to the liquid to be contacted and mixed, it is preferable to separate the resin (B) having aminophosphate groups after mixing using a known separation method such as filtration.

[0030] In the process of bringing a liquid to be contacted with a resin (B) having aminophosphate groups, when the liquid to be contacted is passed through a cylindrical column containing the resin (B) having aminophosphate groups, the weight and volume of the resin (B) having aminophosphate groups relative to the capacity of the cylindrical container constituting the column can be adjusted according to the volume and viscosity of the liquid to be treated.

[0031] The volume of the liquid to be contacted (also called the space velocity) passing through a column packed with the aminophosphate group-containing resin (B) within a unit time can be adjusted according to the weight and volume of the aminophosphate group-containing resin (B) relative to the capacity of the cylindrical container constituting the column, as well as the volume and viscosity of the liquid to be contacted. The space velocity is the value obtained by dividing the volume of solution that passed through the column in one hour by the volume of the packed aminophosphate-containing resin (B), and is preferably between 1 and 5.

[0032] At the end of the step of bringing the liquid to be contacted with the resin (B) having aminophosphate groups, it is preferable that the amounts of iron ions, zinc ions, and tin ions contained in the liquid to be contacted are 5 ppb or less, based on the weight of the sulfonium salt. The contact between the liquid to be contacted and the resin (B) having aminophosphate groups can be repeated until the endpoint is reached.

[0033] By performing the processing steps in the manufacturing method of the present invention, the amount of metal ions contained in the solution (A) containing the triarylsulfonium salt or the pre-treated solution (AZ) can be reduced to 5 ppb or less, not only for sodium ions, potassium ions, calcium ions, iron ions (Fe), zinc ions (Zn), and tin ions (Sn), but also for other metal ions, thereby obtaining a purified triarylsulfonium salt from which impurities such as metal ions have been sufficiently removed.

[0034] In the manufacturing method of the present invention, it is preferable to further carry out a double decomposition reaction step. In the double decomposition reaction, the anion of the triarylsulfonium salt obtained by the reaction is exchanged for another anion.

[0035] The double decomposition reaction step can be carried out by mixing and stirring an aqueous solution of an alkali metal (lithium, sodium, and potassium, etc.) salt with the solution that has undergone the treatment step. The triarylsulfonium salt, whose anions have been exchanged by the double decomposition reaction, can be obtained as a solid or a viscous liquid by filtering off the solid precipitated after the double decomposition reaction, or by extracting the separated oily substance with an organic solvent and removing the organic solvent. The resulting solid or viscous liquid can be washed with a suitable organic solvent as needed, or purified by recrystallization or column chromatography.

[0036] Furthermore, the liquid to be contacted in the processing step may be the solution obtained after performing the double decomposition reaction step on the aforementioned solution (A) or the pre-treated solution (AZ). It is also preferable to perform the double decomposition reaction on the solution containing the purified triarylsulfonium salt after the processing step. In other words, the aforementioned double decomposition reaction may be carried out after the processing step or before the processing step.

[0037] The triarylsulfonium salt obtained by the production method of the present invention has had impurities such as metal ions [sodium ions, potassium ions, calcium ions, iron ions (Fe), zinc ions (Zn), and tin ions (Sn), etc.] sufficiently removed, and can be preferably used as an acid generator. By using the sulfonium salt obtained by the production method of the present invention as an acid generator, high-resolution chemically amplified resists and the like can be obtained. [Examples]

[0038] The present invention will be further described below with reference to examples, but the present invention is not intended to be limited thereto. Unless otherwise specified below, % means weight percent.

[0039] <Example 1> 5.06 g (0.025 mol) of diphenyl sulfoxide was dissolved in 30 g (0.38 mol) of benzene, and 8.46 g (0.03 mol) of trifluoromethanesulfonic anhydride was added dropwise while the system temperature did not exceed -5°C.

[0040] After the dropwise addition was complete, the reaction was allowed to continue at room temperature for 1 hour to complete the dehydration condensation reaction between diphenyl sulfoxide and benzene. The supernatant was removed, and 50 g of deionized water was added to the oily precipitate at a temperature not exceeding 15°C. Then 75 g of tetrahydrofuran and 30 g of toluene were added, and the mixture was stirred for 1 hour. The upper layer was removed, and the remaining solution was washed twice with 30 g of toluene. 100 g of dichloromethane was added for extraction, the aqueous layer was removed, and the organic layer was washed three times with 50 g of deionized water to obtain post-reaction solution (1-1).

[0041] An ORLITE DS-21 (manufactured by Organo) was placed vertically inside a cylindrical column with an inner diameter of 10 mm and a volume of 30 mL, and filled to 20 mL. The post-reaction solution (1-1) was then passed through the column at room temperature at a space velocity of 3.2 to perform the processing step. The solution that had undergone the processing steps was desolvented, and when crystals began to precipitate, 150 g of methyl-tert-butyl ether was added to precipitate white crystals. By filtering and separating these crystals and drying them under reduced pressure, 5.08 g of triphenylsulfonium trifluoromethanesulfonate (purity 99.9% or higher), which is the sulfonium salt (A-1), was obtained.

[0042] <Example 2> 1.07 g (0.044 mol) of powdered magnesium was placed in a four-necked flask equipped with a dropping funnel, thermocouple, and stirrer. The contents of the flask were replaced with nitrogen, and the mixture was stirred at room temperature for 1 hour. Then, 6.28 g (0.040 mol) of bromobenzene was poured into the dropping funnel, and 30 ml of the solvent tetrahydrofuran was added to the reaction vessel. The temperature was raised to 40°C. Next, 0.3 g of bromobenzene was added dropwise from the dropping funnel. Once exothermic reaction was confirmed, bromobenzene was added dropwise over 1 hour, and the reaction was continued for another hour. After cooling to room temperature, a phenylmagnesium bromide solution was obtained. 5.06 g (0.025 mol) of diphenyl sulfoxide and 30 ml of tetrahydrofuran were placed in a four-necked flask, nitrogen was purged, and the mixture was dissolved and cooled to 10°C. The above phenylmagnesium bromide solution was added dropwise at a rate that did not exceed 15°C in the system.

[0043] After the dropwise addition was complete, the reaction was allowed to continue at room temperature for 1 hour to complete the reaction. Toluene and water were added, and the separated toluene was separated and collected. It was mixed with 4.3 g (0.025 mol) of sodium trifluoromethanesulfonate in acetonitrile solution, water was added, and the separated organic phase was collected. It was washed with water, concentrated, and diluted with dichloromethane to obtain a dichloromethane solution of triphenylsulfonium trifluoromethanesulfonate (1-2).

[0044] An ORLITE DS-21 (manufactured by Organo) was placed vertically inside a cylindrical column with an inner diameter of 10 mm and a volume of 30 mL, and filled to 20 mL. The post-reaction solution (1-2) was then passed through the column at room temperature at a space velocity of 3.2 to perform the processing step. The solution that had undergone the processing steps was desolvented, and when crystals began to precipitate, 150 g of methyl-tert-butyl ether was added to precipitate white crystals. By filtering and separating these crystals and drying them under reduced pressure, 5.08 g of triphenylsulfonium trifluoromethanesulfonate (purity 99.9% or higher), which is the sulfonium salt (A-1), was obtained.

[0045] <Example 3> Except for using the post-reaction solution (1-3) obtained by replacing 30 g of benzene in Example 1 with 30 g of toluene, 5.11 g of the target sulfonium salt (A-2), diphenyl(4-methylphenyl)sulfonium-trifluoromethanesulfonate (purity 99.9% or higher), was obtained by the same method as in Example 1.

[0046] <Example 4> To the post-reaction solution (1-1) obtained in Example 1, 50 g of 1% hydrochloric acid aqueous solution was added at room temperature and stirred for 30 minutes, then allowed to stand and the separated aqueous layer was removed. Furthermore, the process of adding 50 g of deionized water, stirring, standing, separation, and removal of the aqueous layer was repeated three times to perform a pretreatment step in which the post-reaction solution (1-1) and the acidic aqueous solution were mixed. Using the pre-treated solutions (1-4) obtained after the pre-treatment step, the same treatment step as in Example 1 was performed, in which the solutions were brought into contact with "ORLITE DS-21" (manufactured by Organo). The solution that had undergone the processing steps was desolvented, and when crystals began to precipitate, 150 g of methyl-tert-butyl ether was added to precipitate white crystals. This crystal was filtered and separated, and then dried under reduced pressure to obtain 4.95 g of triphenylsulfonium trifluoromethanesulfonate (A-1), which has a purity of 99.9% or higher.

[0047] <Example 5> To the post-reaction solution (1-3) obtained in Example 3, 50 g of 1% hydrochloric acid aqueous solution was added at room temperature and stirred for 30 minutes, then allowed to stand and the separated aqueous layer was removed. Furthermore, the process of adding 50 g of deionized water, stirring, standing, separation, and removal of the aqueous layer was repeated three times to perform a pretreatment step in which the post-reaction solution (1-3) and the acidic aqueous solution were mixed. Using the pre-treated solutions (1-5) obtained in the pre-treatment step, the process of contacting them with "ORLITE DS-21" (manufactured by Organo), which is the same as in Example 1, was carried out. The solution that had undergone the processing steps was desolvented, and when crystals began to precipitate, 150 g of methyl-tert-butyl ether was added to precipitate white crystals. This crystal was filtered and separated, and then dried under reduced pressure to obtain 4.99 g of diphenyl(4-methylphenyl)sulfonium trifluoromethanesulfonate (A-2), which is a sulfonium salt (purity of 99.9% or higher).

[0048] <Example 6> 5.06 g (0.025 mol) of diphenyl sulfoxide and 5.40 g (0.050 mol) of anisole were dissolved in 20 g of dichloromethane, and 8.46 g (0.03 mol) of trifluoromethanesulfonic anhydride was added dropwise while the system temperature did not exceed -5°C.

[0049] After the addition of the additives was complete, the reaction was allowed to continue at room temperature for 1 hour to complete the dehydration condensation reaction between diphenyl sulfoxide and anisole. 150 g of methyl-tert butyl ether was added to the reaction mixture to precipitate brown crystals. These crystals were filtered and separated, dissolved in 30 g of dichloromethane, and 100 g (0.075 mol) of a 17% dichloromethane solution of boron tribromide was added dropwise while the system temperature did not exceed 10°C. After the addition of the additives was complete, the reaction was allowed to continue at room temperature for 1 hour to complete the reaction. 50 g of deionized water was added to the reaction mixture to remove the aqueous layer, and the organic layer was washed twice with 50 g of deionized water to obtain the post-reaction solution (1-6).

[0050] A cylindrical column with an inner diameter of 10 mm and a volume of 30 mL, vertically mounted "ORLITE DS-21" (manufactured by Organo), was filled to 20 mL. The post-reaction solutions (1-6) were then passed through the column at room temperature at a space velocity of 3.2, bringing the post-reaction solutions (1-6) into contact with the resin (B) having aminophosphate groups. The solution that had undergone the processing steps was desolvented, and when crystals began to precipitate, 150 g of methyl-tert-butyl ether was added to precipitate white crystals. This crystal was filtered and separated, and dried under reduced pressure to obtain 5.11 g of diphenyl(4-hydroxyphenyl)sulfonium trifluoromethanesulfonate (A-3), which has a purity of 99.9% or higher.

[0051] <Example 7> To the post-reaction solution (1-6) obtained in Example 6, 50 g of 1% hydrochloric acid aqueous solution was added at room temperature and stirred for 30 minutes, then allowed to stand and the separated aqueous layer was removed. Furthermore, the process of adding 50 g of deionized water, stirring, standing, separation, and removal of the aqueous layer was repeated three times to perform a pretreatment step in which the post-reaction solution (1-6) and the acidic aqueous solution were mixed. Using the pre-treated solutions (1-7) obtained in the pre-treatment step, the process of contacting them with "ORLITE DS-21" (manufactured by Organo), which is the same as in Example 1, was carried out. The solution that had undergone the processing steps was desolvented, and when crystals began to precipitate, 150 g of methyl-tert-butyl ether was added to precipitate white crystals. This crystal was filtered and separated, and then dried under reduced pressure to obtain 5.01 g of diphenyl(4-hydroxyphenyl)sulfonium trifluoromethanesulfonate (A-3), which is a sulfonium salt (purity of 99.9% or higher).

[0052] <Comparative Example 1> In Example 1, 5.15 g of triphenylsulfonium trifluoromethanesulfonate (purity 99.9% or higher) was obtained in the same manner as in Example 1, except that the processing step of contacting the post-reaction solution (1-1) with the resin (B) having an aminophosphate group was omitted.

[0053] <Comparative Example 2> In Example 4, 5.09 g of triphenylsulfonium trifluoromethanesulfonate (purity 99.9% or higher) was obtained in the same manner as in Example 4, except that the processing step of contacting the pre-treated solution (1-4) with the resin (B) having an aminophosphate group was omitted.

[0054] <Comparative Example 3> In Example 3, 4.92 g of triphenylsulfonium trifluoromethanesulfonate (purity 99.9% or higher) was obtained in the same manner as in Example 3, except that the granular "ORLITE DS-21" with an aminomethyl phosphate functional group packed into the cylindrical column was changed to "ORLITE DS-22" (manufactured by Organo) with an iminodiacetic acid functional group.

[0055] Table 1 shows the steps taken in Examples 1-7 and Comparative Examples 1-3, as well as the concentrations of metal ions (Na, K, Ca, Fe, Zn, and Sn) contained in the resulting sulfonium salts. The metal ion concentration was measured by inductively coupled plasma mass spectrometry using an Agilent 8800 (product name of Agilent Technologies) as an inductively coupled plasma mass spectrometer.

[0056] [Table 1]

[0057] The results in Table 1 show that the sulfonium salts obtained in Examples 1-7 have a low content of metal ions, which are impurities. [Industrial applicability]

[0058] The sulfonium salt obtained by the manufacturing method of the present invention can be used in paints, coatings, various coating materials (hard coats, stain-resistant coatings, anti-fogging coatings, corrosion-resistant coatings, optical fibers, etc.), back treatment agents for adhesive tapes, release coatings for release sheets for adhesive labels (release paper, release plastic film, release metal foil, etc.), printing plates, dental materials (dental formulations, dental composites), inks, inkjet inks, chemically amplified resists for semiconductor integrated circuits (ultraviolet, deep-UV, KrF excimer laser, ArF excimer laser, electron beam, EUV, X-ray), positive resists (for forming connection terminals and wiring patterns in the manufacture of electronic components such as circuit boards, CSPs, and MEMS elements), resist films, liquid resists, and negative resists (for the surface of semiconductor elements, etc.). It is suitably used as a photoacid generator in permanent film materials such as protective films, interlayer insulating films, and planarization films, MEMS resists, positive-type photosensitive materials, negative-type photosensitive materials, various adhesives (temporary fixing agents for various electronic components, adhesives for HDDs, adhesives for pickup lenses, adhesives for functional films for FPDs (polarizing plates, anti-reflective films, etc.)), holographic resins, FPD materials (color filters, black matrices, partition materials, photospacers, ribs, alignment films for liquid crystals, sealants for FPDs, etc.), optical components, molding materials (for building materials, optical components, lenses), casting materials, putties, glass fiber impregnating agents, sealing materials, encapsulating materials, photoelectronic semiconductor (LED) encapsulating materials, optical waveguide materials, nanoimprint materials, materials for stereolithography, and materials for micro-photolithography.

Claims

1. A method for producing a purified triarylsulfonium salt, comprising a processing step of contacting a solution (A) containing a triarylsulfonium salt with a resin (B) having an aminophosphate group.

2. The method for producing a purified triarylsulfonium salt according to claim 1, wherein the solution (A) containing the triarylsulfonium salt is a post-reaction solution (A1) obtained after a dehydration condensation reaction between a diphenyl sulfoxide compound and a (substituted) benzene, or a post-reaction solution (A2) obtained after a Grignard reaction using a diphenyl sulfoxide compound and a (substituted) phenylmagnesium halide.

3. A pretreatment step of mixing a solution (A) containing the triarylsulfonium salt described in claim 1 with an acidic aqueous solution, A method for producing a purified triarylsulfonium salt, comprising a processing step of contacting a pre-treated solution (AZ) obtained after the above pre-treatment step with a resin (B) having an aminophosphate group.

4. A method for producing a purified triarylsulfonium salt according to claim 3, wherein the acid contained in the acidic aqueous solution is at least one Brønsted acid selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, phosphoric acid, and citric acid.

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