Fabrication of a monolithic microdischarge-based pressure sensor for harsh environments

This paper presents a 6-mask monolithic fabrication process for a pressure sensor that uses a differential microdischarge signal to sense diaphragm deflection. Microdischarge-based transduction is potentially advantageous for device miniaturization and harsh environments because of inherently large signals and immunity to temperature. This work reports a monolithic fabrication process that successfully addresses a number of challenges for microdischarge-based pressure sensors, such as three-dimensional (3D) electrical connection by electroplating laser-drilled through-glass vias (TGVs), and backside terminals for appropriate packages. The device has an exterior volume of 585×540×200 μm3 (0.05 mm3). Preliminary results show an estimated average sensitivity equivalent to 9,800 ppm/MPa over 0-40 MPa pressure range.