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%.
Proc. SPIE. 6151, Emerging Lithographic Technologies X
KEYWORDS: Electron beams, Amplifiers, Control systems, Photomasks, Beam shaping, Optical alignment, Data conversion, Electron beam direct write lithography, Semiconducting wafers, Vestigial sideband modulation
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.