In situ preparation of lithographic resists containing glutarimide groups

Abstract

Poly(acrylic acid) and poly(methacrylic acid) homopolymers, copolymers, and 1‐μ‐thick films have been converted in high yield to their corresponding cyclic imide derivatives by an in situ gas–solid phase reaction at 200°C with ammonia, methylamine, and ethylamine, respectively. Under similar reaction conditions with H2S or CH3SH as the reactive gas, sulfur was incorporated into the polymers in low yield. Under UV and electron beam irradiation, these cyclic derivatives degraded with main chain scission to eliminate isocyanic acid or alkyl isocyanate and to form olefins and ketenes. Poly(diacrylimide) was the exception and crosslinked. The poor solubility in organic solvents and the very high solubility in aqueous solutions of base limited the use of these films as positive resists. However, poly(methyl methacrylate) copolymers, containing 20%–25% cyclic groups, exhibited adequate solubility and sensitivity to be utilized as lithographic resists. Copyright © 1978 John Wiley & Sons, Inc.