Self-Packaging Fabrication of Silicon–Glass-Based Piezoresistive Pressure Sensor

Abstract

A self-packaged piezoresistive pressure sensor was fabricated using a silicon-glass anodic bonding technique. The Wheatstone bridge piezoresistive sensing configuration was located on the lower surface of the silicon diaphragm and was vacuum sealed in a Si-glass cavity, and the embedded Al feedthrough lines at the Si-glass interface were used to realize the electrical connections between the piezoresistive sensing elements and hybrid metal electrode pads through Al vias and heavily doped diffusion zones. The pressure sensors demonstrate comparable performance characteristics, but a more simple process and low cost in comparison with the commercial Si-based piezoresistive pressure sensor. Due to the self-packaging protection, the pressure sensors are capable of handling harsh environments.