Patent ID: 7691561

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 which generates an acid in response to actinic light or radiation, said resin component (A) comprising a polymer consisting of recurring units of the general formula (1): wherein R 1 is independently hydrogen, methyl or trifluoromethyl, R 2 and R 3 are each independently a straight or branched alkyl group of 1 to 4 carbon atoms, R 4 is a straight, branched or cyclic monovalent hydrocarbon group of 1 to 20 carbon atoms optionally containing a heteroatom, X 1 is O, S or CH 2 CH 2 , X 2 is O, S, CH 2 or CH 2 CH 2 , n is 1 or 2, a, b, c, d1 and d2 indicate ratios of the corresponding recurring units, a and b each are from 0.01 to less than 1, c, d1 and d2 each are from 0 to less than 1, with the proviso that d1 and d2 are not equal to 0 at the same time, and a+b+c+d1+d2=1.