Copolymers and terpolyers are used in chemically amplified resists. The terpolymers are of the formula: wherein R3 is selected from the group consisting of hydrogen and a C1 to C10 aliphatic hydrocarbon, wherein the aliphatic hydrocarbon contains substituents selected from the group consisting of hydrogen, hydroxy, carboxylic acid, carboxylic anhydride, and combinations thereof; R4 is selected from the group consisting of hydrogen and a C1 to C10 aliphatic hydrocarbon, wherein the aliphatic hydrocarbon contains substituents selected from the group consisting of hydrogen, hydroxy, carboxylic acid, carboxylic anhydride, and combinations thereof; R5 is selected from the group consisting of hydrogen and methyl; R6 is selected from the group consisting of t-butyl and tetrahydropyranyl; m and n are each integers; and wherein n/(m+n) ranges from about 0.1 to about 0.5.