Pathways to high-performance extreme ultra-violet lithography resists: Dissociative electron attachment to pentafluoro-phenyl triflate

To fully enfold the significant advantage of extreme ultraviolet lithography (EUVL) in the high-volume realization of the next generation technology nodes, high sensitivity EUVL resist formulations, tailored to the electron driven chemistry triggered in EUVL are essential. Here we address this by studying low energy electron-driven chemistry of pentafluorophenyl triflate, a neutral phenyl ester photo acid generator (PAG), i.e., a critical component of the commonly used chemically amplified resist (CAR) formulations. We present an experimental and theoretical study on dissociative electron attachment (DEA) to this compound, and we show that DEA rather quenches, than promotes its intended acid generation. We argue that these findings are general to currently proposed neutral ester PAGs for EUVL, and we propose an approach where this may be upturned, and DEA may contribute significantly to the critical acid generation in CARs up on EUV exposure and thus the sensitivity of these resists.