Patent ID: 6964839

Claim:
A photosensitive copolymer having a weight-average molecular weight of 3,000 to 100,000 and consisting essentially of first and second monomers represented by the following formulae: wherein R 1 is a hydrogen atom or methyl, R 2 is an acid-labile tertiary alkyl group, and m/(m+n) is 0.5 to 0.8, and wherein R 2 is 2-methyl-2-norbornyl, 2-ethyl-2-norbornyl, 2-methyl-2 isobornyl, 2-ethyl-2-isobornyl, 8-methyl-8-tricyclo[5.2.1.0 2,6 ]decanyl, or 8-ethyl-8-tricyclo[5.2.1.0 2,6 ]decanyl.