Design of wide temperature range resonant-mode absolute MEMS pressure sensor

We describe the design and fabrication of a resonant absolute MEMS pressure sensor using a semi-custom fabrication process. We selected a double anchored Double-Ended Tuning Fork (DETF) resonator for this work. The pressure sensor design is based on fabricating two resonant structures side by side using MEMS Integrated Design for Inertial Sensors (MIDIS) process, a commercial pure-play MEMS process recently introduced by Teledyne DALSA Semiconductor Inc. (TDSI). The fabricated devices from MIDIS process are then post-processed to etch the handle wafer below one of the resonator devices (sensor) down to a pre-determined thickness that bends in response to the external ambient pressure. The second resonator is used as the reference where the handle wafer is left untouched. The proposed differential setup enables the pressure sensor to operate over a wide temperature range from -55°C to 225°C.