Silicon-Glass-Silicon Triple Stacked Structure for Fabrication of MEMS Resonator Accelerometer

This paper presents a silicon-glass-silicon triple stacked structure for fabrication of micromachined silicon resonator accelerometer. The triple stacked structure was achieved by two step anodic bonding with a low temperature, pressure and voltage. The glass layer is thinned to no more than 20μm thick and used as the insulating layer, where metal interconnection is present. The finite analysis results demonstrate that the triple structure has small resonant frequency variation under temperature load, -45°C
_~
60°C, and the parasitic capacitance is reduced by one tenth, comparing to that of SOI process. A gridded silicon substrate is designed to to avoid voids generation at the bonding interface. Optimized process parameters are achieved. The applied voltage is in a range of 350V-500V and pressure is in a range of 200N-350N. The wafer level packaged silicon resonator accelerometers are fabricated. This fabrication technique provides support for the design of next-generation high-performance silicon resonator accelerometers.