Hybrid e-beam/deep UV exposure using portable conformable masking (PCM) technique

Abstract

A thin dichroic resist or an opaque metal is directly applied to a deep-UV resist and is delineated with an e-Beam exposure tool conventionally. This intimately contacted pattern now serves as a portable mask that can be carried with the wafer to a deep-UV blanket exposure station for delineation of the deep-UV resist to produce high aspect ratio images with controlled profiles. In particular, AZ1350J/PMMA and AZ1350J/aluminum/PMMA systems are discussed. Sample results showing submicrometer PMMA images in thicknesses ranging from 1.6 to 1.9 μm using a 0.2 μm thick AZ PCM and 0.3-μm-thick aluminum PCM are presented.