A New Type of Eco-Friendly Resist Based on Nonchemically Amplified System

Abstract

Novel water-processable photopolymers were designed to be useful as environment-friendly photolithographic materials. By copolymerization of 2-(2-diazo-3-oxo-butyryloxy)ethyl methacrylate (DOBEMA), hydroxyethyl methacrylate (HEMA), methacryllic acid (NLAA), and sodium 4-vinylbenzenesulfonate (SVBS), two kinds of polymers, poly(DOBEMA-co-HENIA-co-SVBS) for negative-tone resist and poly(DOBEMA-co-MAA) for positive-tone resist, were synthesized and their photolithographic properties were investigated. The single component negative-tone resist produced 0.8 mu m line and space patterns using a mercury-xenon lamp in a contact printing mode using pure water as casting and developing solvent at a exposure dose of 25 mJ cm(-2). On the other hand, the single component positive-tone resist produced 0.8 mu m line and space patterns at a much higher dose of 150 mJ cm(-2). Thus, the negative resist showed much improved sensitivity when compared with the positive resist and the reported nonchemically amplified resists. This sensitivity is comparable with those of typical chemically amplified resists. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7534-7542, 2008