Patent ID: 8048610

Claim:
A polymer comprising recurring units having the general formulae (1), (2) and (3): wherein R 1 is hydrogen, fluorine, methyl or trifluoromethyl, Rf is each independently hydrogen, fluorine, trifluoromethyl or pentafluoroethyl, both Rf's are not hydrogen, A is a divalent C 1 -C 10 organic group which may have fluorine or oxygen substituted thereon, provided that A is not —CH 2 —, 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, N is an integer of 0 to 2, R 8 is hydrogen or C 1 -C 10 alkyl, B is a single bond or a divalent C 1 -C 10 organic group which may have oxygen substituted thereon, a is an integer of 0 to 3, b is an integer of 1 to 3, and X is an acid labile group.