Capacitive pressure sensor with wafer-through silicon vias using SOI-Si direct wafer bonding and glass reflow technique

Abstract

A micromachined capacitive pressure sensor with a single crystal silicon membrane and wafer-through silicon via electrodes embedded in the glass substrate is demonstrated. SOI (silicon-on-insulator)-Si direct wafer bonding and reflow technique of the bonded glass wafer are combined to fabricate the pressure sensor. The proposed process enables to access the sensing capacitor easily from the backside of the substrate without bondwires on the front, and helps to achieve uniform sensor performances thanks to the uniform thickness of the SOI device layer. The fabricated sensors show an initial capacitance of 7.68±0.39pF with an averaged sensitivity of 1.29±0.06fF from 0 to 360 Torr.