Wafer-level vacuum-encapsulated rate gyroscope with high quality factor in a commercial MEMS process

We report the design and fabrication of a rate gyroscope sensor that is characterized by a high quality factor (52,300), unmatched resonance mode and low noise performance. The gyroscope dimensions are 1800 µm × 850 µm with 30 µm device thickness. The gyroscope comprises of a symmetrical resonator for the drive mode oscillation and uses differential capacitance measurement for inertial sensing. The gyroscope is fabricated using MEMS Integrated Design for Inertial Sensors process, which is a new microfabrication process developed by Teledyne DALSA Semiconductor Inc. This new microfabrication technology offers wafer-level encapsulation under high vacuum pressure of 10 mTorr and includes Through Silicon Vias that allows flip-chip bonding with an integrated circuit for signal detection and processing. The fabricated gyroscope was tested and it exhibited a sensitivity of 0.8 fF/°/s with excellent linearity over a wide input angular velocity range of ±1000°/s and a high rate resolution of 0.71°/s.

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