Environmentally friendly negative resists based on acid-catalyzed acetalization for 193-nm lithography

Abstract

Novel water-developable negative resists were designed to induce both crosslinking and polarity change upon exposure and bake. The matrix polymers were synthesized by copolymerization of glyceryl methacrylate and methacrolein. The acid-catalyzed acetalization of the polymer induced crosslinking , polarity change, and an increase in dry-etch resistance. The resist formulated with this polymer and cast in a water/ethanol mixture showed 0.7 mum line and space patterns using a mercury-xenon lamp in a contact printing mode and pure water as a developer.