Patent ID: 8057985

Claim:
A sulfonium salt having the general formula (1): wherein R 1 is hydrogen, fluorine, methyl or trifluoromethyl, R 2 , R 3 and R 4 are each independently a substituted or unsubstituted, straight or branched C 1 -C 10 alkyl, alkenyl or oxoalkyl group or a substituted or unsubstituted C 6 -C 18 aryl, aralkyl or aryloxoalkyl group, or at least two of R 2 , R 3 and R 4 may bond together to form a ring with the sulfur atom to which they are attached, A is a divalent C 1 -C 20 organic group which may contain a heteroatom, and n is 0 or 1.