Novel sulfonylimide photo-acid generators for deep ultraviolet photoresist with improved acid diffusion inhibition performance through retarding the anion diffusion

A series of novel ionic photo-acid generators (PAGs) useful in chemically amplified photoresist formulations has been developed, which are salts comprising a photoactive triphenyl cation and a sulfonylimide anion containing an aromatic group. A styrene-based polymer resin is prepared by reversible addition-fragmentation chain transfer (RAFT) polymerization and blended with the novel PAGs as deep ultraviolet (DUV) photoresists. Furthermore, one of the novel PAGs is used as a monomer to be bound into the polymer resin through RAFT polymerization to obtain a photoresist-PAG copolymer. The prepared photoresists are exposed by a DUV light to study their sensitivity, acid diffusion length, and lithography pattern profile. The results show that both the photoresists blended with the novel PAGs and the photoresist-PAG copolymer exhibit good resistance to acid diffusion and low line sidewall roughness (LSR).