High-current Oxygen Ion Implanter for SIMOX

OVERVIEW: SOI (silicon on insulator) technology* has attracted a lot of attention as a promising breakthrough technology for high-speed, low-power LSIs. Research and development aimed at its practical use are now being conducted over a wide range of fields, including circuit design, device, process, and SOI wafer manufacturing. The key to the practical use of SIMOX (separation by implanted oxygen) technology, an important SOI technology, depends on how satisfactory performance we can obtain in ion implanters which are used for implanting oxygen ions into Si to form a buried oxide layer. In ion implanters for SIMOX, practical productivity as well as wafer quality enabling manufacture of advanced LSIs must be ensured at the same time. This requirement leads to the necessity of higher performance implanters enabling high current (50 – 100 mA), high temperature (– 550°C), uniform, low contamination and low particle level implantation, exceeding the concept of conventional ion implantation. Hitachi, Ltd. has developed UI-5000, a high-current oxygen ion implanter for SIMOX. Its basic design concepts are the use of a microwave ion source and a mechanical scanning scheme. The implanter has already been applied to SIMOX wafer production and has shown good performance — it has an implant current of 70 mA during regular operation and an implantation uniformity of 2% or better (determined by film thickness uniformity). This implanter will potentially lead to volume production of SIMOX wafers. Akira Yoshikawa Isao Hashimoto Kazuo Mera Katsumi Tokiguchi, D. Eng.