New, deep UV resist (LMR) for lift-off technique

Abstract

A new, deep UV resist, LMR (low molecular weight resist) has been developed. LMR is a quinone–diazide ester of a novolak resin whose molecular weight is about 1000. It has strong absorption in the deep UV region (12 μm−1 at 250 nm). LMR is negative working upon irradiation with deep UV light and forms an overhung structure with a single development step. The sensitivity of LMR is 30 mJ/cm2 and 0.3 μm wide spaces are clearly resolved. By use of LMR, a simple and reliable lift-off process is realized. Submicron wide metal patterns having a thickness twice that of the resist can be formed by this process.