Patent ID: 7622242

Claim:
A resist composition comprising a polymer which changes its alkali solubility under the action of an acid as a base resin, and a copolymer comprising recurring units (a) and (b) of the general formula (1) as an additive, wherein R 1 is fluorine or trifluoromethyl, R 2 and R 3 are hydrogen or a straight, branched or cyclic C 1 -C 20 alkyl group, or R 2 and R 3 may bond together to form a ring with the carbon atom to which they are attached, and in this case, R 2 and R 3 together represent a straight, branched or cyclic C 2 -C 20 alkylene group, R 4 is hydrogen or an acid labile group, R 5 to R 8 are independently selected from the group consisting of hydrogen, fluorine, and a straight, branched or cyclic C 1 -C 20 alkyl group, which may contain at least one ether or ester group, may be substituted with fluorine, and may contain a hydroxy group, or any two of R 5 to R 8 may bond together to form a ring with the carbon atom(s) to which they are attached, m is 0 or 1, a and b are numbers in the range: 0.2≦a≦0.8, and 0.1≦b≦0.6.