Preparation of a photoacid generating monomer and its application in lithography

A photoacid generating (PAG) monomer containing a sulfonium group was synth esized and its polymerization behavior was investigated by conducting homop olymerization and copolymerization with various methacrylates found in chem ically amplified photoresists. The PAG homopolymer itself acted as a high s ensitivity negative resist. The PAG/methacrylates copolymers functioned as novel chemically amplified (CA) resists with PAGs incorporated in the polym er chain. Due to absence of phase separation, the resists exhibited excelle nt film formation behavior. Preliminary results have shown that acid genera tion efficiency remained almost the same regardless of remarkably differing components and compositions in the PAG/methacrylates copolymers. Finally, their imaging properties were investigated by exposure to 248 nm deep-ultra violet (DUV) radiation.