A Dual-Mass Fused-Silica MEMS Gyroscope With High-Aspect-Ratio Comb Electrodes Based on ML-LIAE

Fused silica is an ideal material for manufacturing MEMS devices due to its excellent mechanical and thermal properties. However, processing fused silica, especially high-aspect-ratio and high-density comb structures, remains challenging. As the spacing of gaps decreases, the process will fail. In this study, we propose a method of multi-layer laser-induced assisted etching (ML-LIAE) that successfully fabricates high-density combs. Using this technique, we report for the first time a fused silica dual-mass MEMS gyroscope with comb electrodes having an aspect ratio of 50:1. The gyroscope has a frequency of about 9900 Hz and a Q-factor of over 80000 in a vacuum of 0.01Pa. The capacitance of a pair of comb electrodes reaches 2pF, with a total of 16 pairs in this gyroscope. ML-LIAE provides a feasible and reliable solution for fabricating MEMS structures with higher aspect ratio and denser combs.[2026-0154]