A Character Projection Low Energy Electron Beam Direct Writing System for Device of Small Production Lot with a Variety of Design

摘要

A character projection (CP)-type, low energy, electron beam direct writing (EBDW) system, for quick-turn-around-time and mask-less device fabrications of small production lots featuring a variety of designs has been developed. This system, named the EBIS (Electron Beam Integrated System), can satisfy a set of requirements for EBDWs, including higher throughput and mask-less exposure. A standardized CP aperture method that enables reduction in the number of EB shots without frequent aperture making has been applied as a means for attaining effective CP and mask-less fabrication. This breakthrough was able to be realized only by using low energy EB with the advantage of the free proximity effect. To resolve critical low energy EB issues, a compact EB column, equipped with monolithic deflectors and lenses for restricting beam blur caused by Coulomb interaction, was developed and put to use. Sufficient resolution, corresponding to 100 nm L/S patterns, was attained by using a thin-layered resist process. As the mark detection method, voltage contrast imaging using a micro channel plate was used. This method made it possible to detect buried marks when using low energy EB. The authors are currently verifying the basic performance of this EBIS. This paper outlines and discusses geometrical details and performance data of this system.