KrF TRILAYER RESIST SYSTEM USING AZIDE-PHENOL RESIN RESIST

Abstract

Azide-phenol resin resist is applied to a trilayer resist system for KrF excimer lithography. It was found that smaller size patterning below 0.2-μm-level limit the film thickness to 0.5μm of bottom layer due to pattern collapse and micro-loading during the dry etching processes. Under such condition, the analysis of multi-interference effect for trilayer resist system leads to a photoabsorptive resist as a top layer. The photoabsorptive resist with extinction coefficient of 0.045 for trilayer resist system gives linewidth variation less than 0.005μm, resolution limit of 0.15-μm L/S and depth of focus of ±0.8μm for 0.16-μm L/S pattern.