Imido-Based Non-Ionic Photoacid Generators Targeted for Double Amplification EUV Resists

In the semiconductor industry, extreme ultraviolet (EUV) lithography is a critical technology to achieve smaller feature sizes for next-generation nodes. Conventional EUV photoresists typically contain photoacid generators (PAGs), which form strong acid catalysts after exposure to EUV photons. While onium salt-based ionic PAGs are the most widely used in the field, nonionic PAGs may offer improved miscibility and homogeneity in organic polymer matrices. In this study, we designed a series of trimellitimide-based nonionic PAGs, guided by density functional theory (DFT) calculations to predict key photophysical properties. This combined computational and experimental approach offers valuable insights into structure–property relationships. The PAGs were evaluated under both EUV (13.5 nm) and deep ultraviolet (DUV, KrF) exposure, incorporated within either a conventional chemically amplified resist (CAR) or a double amplification resist (DAR) polymer matrix. It was demonstrated that these PAGs are sensitive to both DUV and EUV exposure. The observed high contrast and fast photospeed in the DAR system highlight N-hydroxy trimellitimide (TMI) PAG’s potential for next-generation photoresist materials in semiconductor manufacturing.