Wafer-Level Fabrication Process for Micro Hemispherical Resonators

This paper reports a wafer-level fabrication process for micro hemispherical resonators. Three-dimensional (3-D) structures are formed by high-temperature glassblowing individually to further enhance the structural symmetry. And then these structures are aligned and mounted on a 4-inch jig wafer, following processes including ultrafast laser ablation, metallization and bonding to electrode wafer are accomplished on wafer level. 3-D fused silica resonators with extremely symmetry, easy-operation and compatibility to MEMS procedure are simultaneously realized in this process. Devices with capacitive gap ≈15µm and alignment error below 35 µm are realized. Finally, these devices are characterized through capacitive measurement in vacuum, with n=2 wineglass mode ranging from 8.9 kHz to 9.7 kHz and quality factors between 47,073 to 55,026. The process is promising for the manufacturing of high-performance MEMS devices such as micro hemispherical resonator gyroscopes (µHRG).