Fluidity dependence of deprotonation kinetics of chemically amplified resist

Chemically amplified resists have been widely used in the mass production line. An acid generation mechanism induced by ionizing radiation with extreme ultraviolet (EUV) and electron beam is an important issue for improvement of the resist performance such as sensitivity, roughness, and resolution below 16 nm. However, the details of deprotonation kinetics from the ionized resist solid film immediately after the ionization have been still unclear. In this study, pulse radiolysis of highly concentrated poly(4-hydroxystylene) (PHS) solutions was performed. The viscosity dependence on the deprotonation dynamics of the ionized concentrated solutions was investigated to clarify the proton generation of ionized PHS in a medium with low mobility. The deprotonation from the PHS radical cation becomes slower with increasing PHS concentration. It is suggested that the deprotonation reaction is slower in a less mobile medium because of decrease of the molecular motions.