ZEP520A (1 : 1 copolymer of α-chloromethacrylate and α-methylstyrene, ZEON) is a main-chain scission-type positive-tone resist used for electron beam (EB) lithography and is known for its high sensitivity and high resolution. In this study, ZEP520A was irradiated using a 100 kV EB, and the decomposition mechanisms were analyzed by gel permeation chromatography, Fourier transform IR spectroscopy, NMR spectroscopy, and pulse radiolysis. Chlorines were confirmed to easily dissociate as Cl - ions (dissociative electron attachment, DEA) and ZEP520A underwent β-scission. Multiple channels could be considered for the main-chain scission, including DEA and the charge transfer complex between phenyl radical cations and Cl - ions.
ASJC Scopus subject areas
- Physics and Astronomy(all)