Patent ID: 8216766

Claim:
A polymer having a rate of dissolution in an alkaline developer that increases under the action of acid, represented by the general formula [1]: wherein a, b, c and d indicative of proportions of the respective recurring units relative to the overall number of recurring units are in the range: 0<a<1, 0b≦1, 0≦c<1, 0≦d<1, and a+b+c+d=1; j is each independently 0 or 1; k is 0 or 1; R 1 is each independently hydrogen or methyl; R 2 is hydrogen or a single bond; R 3 is a straight, branched and/or cyclic C 1 -C 20 alkyl group which may have an oxygen functional group; when R 2 is a single bond, R 2 bonds with R 3 wherein —R 2 —R 3 — is a straight, branched or cyclic C 1 -C 20 alkylene group which may have an oxygen functional group; R 4 is each independently methylene or oxygen; and R 5 is a C 2 -C 20 acid labile group.