Negative Electron Beam Resists Using Ring-Chain Tautomerism of Benzoic Acid Derivatives

Abstract

New negative electron-beam (EB) resists based on ring-chain tautomerism of benzoic acid derivatives have been developed. o-Acetylbenzoic acid (ABA), which converts into the ring-tautomer through a hydrogen transfer from the carboxyl group to the carbonyl group, was selected as the precursor of dissolution inhibitor for the new resist. The resist composed of ABA, diphenyliodonium triflate, and m,p-cresol novolak resin enables us to define 300-nm line and 500-nm space patterns with a dose of 75 µ,C/cm2 at 70kV. Spectroscopic studies show that the acid-catalyzed protection of hydroxyl groups of novolak resin brought about by ABA is responsible for the resist insolubilization.