Patent ID: 8574817

Claim:
A positive resist composition comprising as a base resin a polymer having carboxyl groups whose hydrogen is substituted by an acid labile group having the general formula (1), (2) or (3): wherein R 1 , R 2 , R 5 , R 6 , R 8 , and R 9 are each independently a straight, branched or cyclic C 1 -C 8 alkyl, C 6 -C 10 aryl, or C 2 -C 10 alkenyl group, which may contain an oxygen or sulfur atom, R 3 , R 4 , R 7 , R 10 , and R 11 are each independently hydrogen, a straight, branched or cyclic C 1 -C 6 alkyl, alkoxy, acyloxy, halogen, cyano, nitro, hydroxyl, or trifluoromethyl group, M is methylene or ethylene, R is a single bond or a C 1 -C 2 linking group which may contain a double bond, oxygen atom or sulfur atom.