Patent ID: 7618764

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 having the general formula (I): wherein R 1 is each independently hydrogen, methyl or trifluoromethyl, R 2 is an acid labile group, R 3 is hydrogen or CO 2 R 4 , R 4 is a straight, branched or cyclic monovalent hydrocarbon group of 1 to 20 carbon atoms which may contain a heteroatom, X is O, S, CH 2 or CH 2 CH 2 , R 2 ′ is a fluorinated substituent group of 1 to 15 carbon atoms, m is 1 or 2, n is 1 or 2, a, b, c, d and e are indicative of ratios of the corresponding recurring units, a, b and c are each independently a number in the range from 0.01 to less than 1, one of d and e is a number in the range from 0.01 to less than 1 and another is 0, and a+b+c+d+e =1, and wherein R 5 , R 6 , and R 7 are each independently hydrogen or a straight, branched or cyclic monovalent hydrocarbon group of 1 to 20 carbon atoms which may contain a heteroatom, and R 8 is a straight, branched or cyclic monovalent hydrocarbon group of 7 to 30 carbon atoms which may contain a heteroatom.