Chemical Reaction Analysis of EUV CA Resist using SR Absorption Spectroscopy

It had been reported that tri-phenysulfonium cyclo(1,3-perfluoropropanedisulfone) imidate (TPS-IMIDATE) as a photo acid generator has approximately four times faster sensitive rather than tri-phenysulfonium perfluorobutanesulfonate (TPS-PFBS) under the EUV exposure. In this paper, we discussed the differences of the sensitivity and the chemical reaction between TPS-IMIDATE and TPS-PFBS, on the basis of the EUV-induced analysis of the SR absorption spectroscopy. From the analysis of the SR absorption spectroscopy, F and C atoms in the anion of TPS-IMIDATE decomposed rather than that of TPS-PFBS. The sensitivity advantage of TPS-IMIDATE might own to the anion decomposition reaction. The anion decomposition reaction might be originated to the photo-excitation of the photoacid generator. The anion of TPS-IMIDATE decomposed to smaller molecule and the sensitivity becomes higher.