Patent ID: 8921025

Claim:
A positive resist composition comprising: (A) a resin component which becomes soluble in an alkaline developer under the action of an acid and (B) a compound capable of generating an acid in response to actinic light or radiation, wherein said resin component (A) is a polymer comprising recurring units represented by the general formula (2): wherein R 1 is each independently hydrogen, methyl or trifluoromethyl, R 2 and R 4 each are an acid labile group, R 3 is CO 2 CH 3 , X is O, S, CH 2 or CH 2 CH 2 , m is 1 or 2, n is 1 or 2, a, b, c, d and e are indicative of ratios of the respective units incorporated, 0.05≦a≦0.4, 0.05≦b≦0.4, 0≦c≦0.4, 0.05≦d≦0.3, 0.05≦e≦0.4, and a+b+c+d+e=1, and the acid labile group of R 2 is one or more group selected from groups having the following formulae (a-1) to (a-3): wherein the broken line denotes a valence bond, and R 9 , R 10 , R 11 , and R 12 are each independently a straight or branched alkyl group of 1 to 4 carbon atoms, and said compound (B) is a sulfonium salt compound selected from the group consisting of those represented by the following formulae: