Patent ID: 8603728

Claim:
A copolymer, comprising the polymerized product of a base-soluble monomer of formula (I): wherein: R a is H, F, C 1-10 alkyl, or C 1-10 fluoroalkyl, L 1 is an m+1 valent C 2-30 alkylene, C 3-30 cycloalkylene, C 6-30 arylene, C 7-30 aralkylene group, m+1 is an integer of 2 to 5, each X 1 is independently wherein R b is C 1-20 alkyl; C 1-20 fluoroalkyl, C 3-20 cycloalkyl, C 6-20 aryl, C 7-20 aralkyl, or a combination comprising at least one of the foregoing, and an additional monomer copolymerizable with the base-soluble monomer of formula (I); wherein the additional monomer is a (meth)acrylate monomer having an acid deprotectable base soluble group, a (meth)acrylate monomer having a lactone functional group, a (meth)acrylate monomer having a base-soluble group not identical to that of formula (I), or a combination comprising at least one of the foregoing monomers.