Hiroyuki Shinozaki

A character projection low energy electron beam direct writing system for device of small production lot with a variety of design

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.

Recent progress of a character projection-type low-energy electron-beam direct writing system

We have developed a Character Projection (CP)-type, low-energy Electron-Beam Direct Writing (EBDW) system for a quick turnaround time and mask-less device fabrication of small production lots with a variety of designs. The exposure time has been decreasing because the irradiation time of electrons is being reduced by development of high-sensitivity resist and by decrease in the number of EB shots with the CP method, and the amplifiers of the deflectors have attained specifications required by EBIS. In order to further increase the throughput, overhead time, that is, the exposure waiting time, must be shortened. This paper describes our strategy for reducing the exposure waiting time. The reduction ratio of the exposure waiting time was about 60% and the throughput was increased about 20%.