Patent ID: 7105269

Claim:
A copolymer having recurring units of the following formulas (1), (2), and (3), wherein R 1, represents a hydrogen atom, R 2 and R 3 individually represent a monovalent organic group, k is an integer of 1 or 2, and 1 is an integer of 0 to 4, wherein R 4 represents a hydrogen atom or a methyl group, R 5 represents a monovalent organic group, n is an integer of 1 to 3, and m is an integer of 0 to 3, and wherein R 6 represents a hydrogen atom or a methyl group, R 7 represents a monovalent organic group, R 8 indicates a substituted methyl group, 1-substituted ethyl group, 1-branched alkyl group, triorganosilyl group, triorganogermyl group, alkoxycarbonyl group, acyl group, or cyclic acid-dissociable group, with two or more R 8 groups being either the same or different, q is an integer of 1 to 3, and p is an integer of 0 to 3, the copolymer having a polystyrene-reduced weight average molecular weight determined by gel permeation chromatography (GPC) of 3,000–100,000.