Cavity-Through Deep Reactive Ion Etching of Directly-Bonded Silicon Wafers

摘要

Etched silicon wafers were directly bonded, and then the bonded silicon wafers were deeply etched by Bosch process through etched cavities. This cavity-through DRIE (deep reactive ion etching) was investigated after systematic study on plasma-assisted silicon direct bonding. The first half of this paper mainly reports the generation of voids in wafers directly bonded with N2 or O2 plasma treatment due to H2O release from hydroxy groups in low and high temperature annealing. The second half reports etch profiles and etch rates for cavity-through DRIE using different recipes. Cavity-through DRIE in conjunction with silicon direct bonding is practical and useful for multi-layer MEMS.