Polymers, resist compositions and patterning process

摘要

Polymers comprising recurring units of formula (1) and recurring units having acid labile groups are novel.At least one of R1 and R2 is fluorine or a trifluoromethyl group, and the remainder is hydrogen or a C1-20 alkyl, R3 and R4 each are hydrogen or an unsubstituted or fluorine-substituted C1-20 alkyl, or R3 and R4 may form a ring. Using such polymers, resist compositions featuring transparency to excimer laser light and alkali solubility are obtained.