A de-coupled vibratory gyroscope using a mixed micro-machining technology

This paper presents the highly reliable and wafer level vacuum packaged vertical micro-gyroscope with decoupled vibrating structures. In order to increase the sensitivity by exact tuning the resonant modes without instability problem, we devised two torsion springs for sensing mode in addition to four driving springs attached to outer gimbal. For the fabrication of the proposed gyroscope with high aspect ratio and wafer level vacuum packaging, we used the mixed micro-machining process which has the merits of a conventional surface and bulk micro-machining process. The measured vacuum level of the fabricated gyroscope was about 100 mTorr and the driving and sensing mode frequencies were tuned in 5 Hz. The gyroscope has the sensitivity of 0.013 deg./sec and bandwidth of 60 Hz. The output non-linearity is below than 2% in +100 deg./sec full scale.