Fabrication of packaged thin beam structures by an improved drying method

Abstract

Fabrication of a silicon thin beam structure bonded to a glass with a very narrow gap is needed to make highly sensitive sensors. In fabrication process of the thin beam structure, rinsing and drying process using Fluorinert, which indicates small surface tension, has been investigated to reduce stiction and collapse. Drying after rinsing in ethyl ether and Fluorinert successively was found effective to keep the silicon wafer surface clean. With this method, glass could be bonded to the silicon wafer and packaged thin beam structures were obtained. The narrow achieved gap between silicon thin (1.2 /spl mu/m) beam and bonded glass was 0.7 /spl mu/m. Owing to the improvement of the wafer holder and the interferometric thickness measurement, silicon thin beam of 0.27 /spl mu/m in thickness was achieved.