Optimization of photoacid generator in CA resist for EUVL

摘要

We succeed in developing beneficial photoacid generator (PAG) for EUV exposure. In a high annealing type resist system in which poly-hydroxystyrene employed as a base resin, we found that sulfonium salts which employed cyclo(1,3-perfluoropropanedisulfone) imidate employed as a anion of PAG is more sensitive than perfluorobutanesulfonate employed as an anion of PAG under extreme ultraviolet (EUV) exposure. However, the sensitivities were different under EUV and electron beam (EB) exposures. It indicates that the distinctive acid production reaction is occurred under EUV exposure in comparing under EB exposure. As results of the time dependency mass spectroscopy and the Fourier Transform Infrared Spectroscopy (FT-IR), EUV induced reaction of cyclo(1,3-perfluoropropanedisulfone) imidate employed as an anion of PAG occurred more efficiently than that of perfluorobutanesulfonate employed as an anion of PAG.