Patent ID: 8450042

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): wherein R 1 and R 2 each are hydrogen, a C 1 -C 4 alkyl, alkoxy, alkanoyl or alkoxycarbonyl group, hydroxyl, C 6 -C 10 aryl group, halogen, or cyano group, R is a straight, branched or cyclic C 1 -C 12 alkyl group which may have an oxygen or sulfur atom, C 2 -C 12 alkenyl group, or C 2 -C 12 alkynyl group, R 3 to R 6 are hydrogen or a pair of R 3 and R 4 , R 4 and R 5 , or R 5 and R 6 may bond together to form a benzene ring, and m and n each are an integer of 1 to 4.