Controlled capacitive gaps for electrostatic actuation and tuning of 3D fused quartz micro wineglass resonator gyroscope

In this paper, we present the assembly process and an electrostatic actuation, detection, and tuning method of micro-glassblown wineglass resonators using an out-of-plane electrode architecture with controlled uniform capacitive gaps. This process is developed based on wafer-level deposition of a sacrificial layer on planar electrodes wafer to achieve a uniform electrostatic gap (<5µm). The materials, bonding type, etch selectivity, temperature and vacuum compatibility of the process are considered in the assembly process of the micro-glassblown fused quartz shell resonators. Tuning the frequency mismatch between two orthogonal (n=2) in-plane wineglass modes is demonstrated experimentally on a 7 mm micro-glassblown wineglass resonator using the out-of-plane electrodes. An open-loop rate response is demonstrated using out-of-plane capacitive actuation and detection. The proposed process enables a low-cost assembly with a high transduction efficiency toward wafer-scale fabrication of micro 3D wineglass gyroscopes.