Copolymers for photoresists and processes therefor

Abstract

Fluoroolefin/acid group or protected acid group-containing copolymers for photoresist compositions and microlithography methods employing the photoresist compositions are described. These copolymer compositions comprise 1) at least one fluoroolefin, preferably hexafluoroisobutylene, and 2) an acid group or a protected acid group (e.g., a t-alkyl ester, preferably a t-butyl ester), which together impart high ultraviolet (UV) transparency and developability in basic media to these materials. The materials of this invention have high UV transparency, particularly at short wavelengths, e.g., 157 nm and 193 nm, which makes them useful for lithography at these short wavelengths.

Dependencies are inferred from the claim text.