Glass reflow process for microsystem applications

Abstract

This paper reports on a glass reflow process and its applications to microsystems. Glass compounded silicon structures are achieved using a silicon mold under a high temperature environment, a long process time and assistance of enhancement of the surface wettability. Three applications employing the glass reflow process have been proposed and investigated. Firstly, the silicon through-wafer interconnects, embedded inside the Tempax glass, have been successfully demonstrated and show a resistance of about 10 Ω per feed-through. Secondly, a thick glass layer for thermal isolations is reported. The compounded glass can thermally isolate the heated silicon with a temperature difference of more than 100 °C when the temperature of the silicon part is 140 °C at an input power of 200 mW. Additionally, the silicon micro-heater is also evaluated for its reliability. Lastly, glass capillaries and pillars with and without liquid penetration have been proposed for obtaining the high resolution light field information. The optical windows integrated with an image sensor for an optical modulator are clearly demonstrated and a light modulation effect dependent on liquid penetration is observed.