Low Ea chemical amplification resists for 193nm lithography

193 nm lithography including immersion lithography is drawing attention as the successor of optical lithography for the technology nodes of 65 nm, 45 nm, and possibly even beyond 32 nm (Kishimura, 2005). Therefore, there have been many researches for the base polymer and monomer materials for 193nm chemical amplification positive-tone resists. However, in the 193nm resists systems, previous reports of protecting group of carboxylic acid have been limited to alkoxy-ethyl acetal type, tertiary alkyl, tert-butoxycarbonyl, or tert-butoxycarbonylmethyl (Ito, 2005).