Fine Pattern Fabrication by the Molded Mask Method (Nanoimprint Lithography) in the 1970s

Abstract

Nanoimprint lithography has recently been attracting the attention of many researchers in the field of nanofabrication technology. Although the study of nanoimprint lithography was initiated by Chou et al. around 1995, a fine-pattern fabrication technology, whose concept is similar to nanoimprint lithography, had been proposed and studied at NTT Laboratories in Japan as early as in the 1970s. The technology was based on the combination of the molding of plastic film on a substrate and dry etching of the molded film and substrate surface. It is considered that most of the basic concepts in current nanoimprint lithography were included in this early study. Some demonstration experiments using diffraction gratings, microsized test patterns, LSI patterns and microlenses were carried out to verify the feasibility of the technology at that time. The key point of the technology to fabricate fine patterns accurately was the fluidity of the plastic film. It was called the “Molded Mask Method” and this paper introduces the study on the molded mask method of those days.