Improved 0.12 /spl mu/m EB direct writing for Gbit DRAM fabrication

Abstract

Recently, electron beam (EB) direct writing has been put to practical use in advanced device fabrication, using for example, a cell projection (CP) method, a variably continuous moving stage, a high current density EB, and high speed deflector amplifier, all of which increase the writing throughput of the EB direct writing system. However, for EB direct writing to be used for advanced DRAMs, the following three techniques must each be improved and then combined successfully: (1) a resist process for obtaining reliable fine patterns, (2) a proximity effect correction for the CP method, and (3) CP EB direct writing (CP mask pattern selection) for improving the writing throughput. This article describes improved 0.12 /spl mu/m EB direct writing for Gbit DRAM fabrication.