Photoresist material and method for lithography

Abstract

A photoresist composition comprises an acid-cleavable copolymer formed from oligomers in a backbone or an arm of the copolymer. Each oligomer comprises an acid-labile group; a first comonomer having an acidic leaving substituent; and at least one of a second comonomer having a proton donating substituent or a third comonomer having a polar substituent. The copolymer may also include a RAFT (Reversible Addition Fragmentation chain Transfer) chain transfer agent. Upon exposure to radiation, acid is generated that cleaves the copolymer. This improves the line edge roughness (LER) of the photoresist layer while maintaining good coating properties.

Dependencies are inferred from the claim text.