Fused Silica Micro Shell Resonators by a Wafer-Level Thermal Reflow Process

This article demonstrates a low-cost micro shell resonator forming by the wafer-level negative pressure driven reflow process. Negative pressure in the sealed mold cavity of the bonded fused silica (FS) wafers is used as the driving force of the micro shell structure at reflow temperature. Geometry influence on the resonator’s frequencies and physical parameters is analyzed by Finite Element Modeling (FEM). The micro FS shell resonator with a radius of 1.430 mm was demonstrated, which is now the smallest blown FS shell resonator. Laser Doppler Vibrometer (LDV) measurement shows that the maximum quality factor (Q -factor) at the n = 2 mode frequency of the fabricated resonator is 546.5k, and the minimum n = 2 mode frequency split is 6.6 Hz. The shell also provides low assembly errors by directly anchoring at the center of the mold during bonding process. Our preliminary results provide a possibility for obtaining micro high-performance, small-size, and low-cost 3-D shell gyroscopes. [2024-0101]