Photoacid generator, method for producing the same, and resist composition comprising the same
A photoacid generator represented by the following formula (1), a method for producing the photoacid generator, and a resist composition containing the photoacid generator are provided. wherein in the formula (1), Y, X, R 1 , R 2 , n 1 , n 2 and A + have the same meanings as defined in the detailed description of the invention. The photoacid generator can maintain an appropriate contact angle at the time of ArF liquid immersion lithography, can reduce defects occurring during liquid immersion lithography, and has excellent solubility in resist solvents and excellent compatibility with resins. Furthermore, the photoacid generator can be produced by an efficient and simple method using an epoxy compound that is industrially easily available.
1. A photoacid generator selected from the group consisting of compounds represented by the following formulas (3-1) to (3-12):
A + represents an organic counterion.
2. A method for producing the photoacid generator according to claim 1 , the method comprising:
a first step of allowing a hydroxysulfonic acid salt to react with an oxirane, and thereby producing a hydroxyethoxysulfonic acid salt; and
a second step of subjecting the hydroxyethoxysulfonic acid salt thus produced to a substitution reaction of the cation, and thereby producing the photoacid generator selected from the group consisting of compounds represented by formulas (3-1) to (3-12).
3. The method of claim 2 , wherein the first step is carried out by allowing the hydroxysulfonic acid salt and the oxirane to react in the presence of any one catalyst selected from the group consisting of an acidic catalyst and a basic catalyst.
4. The method of claim 2 , wherein the first step is carried out by mixing the hydroxysulfonic acid salt and the oxirane, and then allowing the mixture to react for 1 to 48 hours at 0° C. to 100° C. under stirring.
5. A resist composition comprising the photoacid generator according to claim 1 .