Study on an Improved Wafer Level Fabrication Process to Achieve Size Uniformity for Micro Glass Shell Resonators

The size of the 3D micro glass shell resonator is one of the main factors affecting the performance of the micro shell resonator gyroscopes (μSRG) such as resonant frequency and quality factor. Different sizes result in different resonant frequencies, which will directly affect the performance of the μSRG. Therefore, for wafer-level fabrication process of micro shell resonators, ensuring size uniformity is an important issue that must be considered. The original wafer-level method for the preparation of micro shell resonators - chemical foaming process (CFP), cannot guarantee that all the resonators on the wafer have the same size. In this paper, an improved process is investigated to improve size uniformity of wafer level shell resonators. Through the measurement, the standard deviation of the height of micro shell resonators on the wafer is reduced from 0.12 to 0.08, and the range is reduced from 480 μm to 350 μm. The improved process shows potential for improving size uniformity.