Photoinitiated Cross-Linking and Image Formation in Thin Polymer Films Containing a Transition Metal Compound

Films spin-coated from solutions containing the copolymer of glycidyl methacrylate and ethyl acrylate and the transition metal salt CO(NH3)5Br2 undergo cross-linking upon irradiation at 254 nm and subsequent heating at 70°C. The mechanism of cross-linking proceeds in two distinct stages: (i) the primary photochemical process involving redox decomposition of the cobalt salt; (ii) one or more thermally activated reaction(s) between the decomposition products and the pendant epoxide groups of the copolymer. Half-micron films retain 50% of their thickness at a dose of 35–40 mJ/cm2, and the system possesses a contrast near two. Preliminary lithographic evaluation of this material reveals that images with features in the 1–2 μm range can be resolved. © 1987, The Electrochemical Society, Inc. All rights reserved.