Changes in molecular weight distribution caused by main-chain scission of electron beam resists

Abstract Main-chain-scission-type resists have attracted much attention as the next-generation electron beam (EB) resist used for photomask fabrication. In this study, the gel permeation chromatography (GPC) charts of irradiated EB resists (ZEP series of ZEON) were analyzed by simulation to clarify the changes in the molecular weight distribution caused by the main-chain scission of a resist polymer. In the low-exposure-dose region, the molecular weight distribution obtained by GPC was well reproduced by the simulation using a random-scission model. In the high-exposure-dose region, the calculated molecular weight distribution deviated from the experimental one because of crosslinking and the generation of stable components.