2005DHH

黃鐙輝 (Deng-Huei Hwang)

Structure Design of a 2D Freqeuncy Shift Microaccelerometer

二維頻率偏移式微型加速度計結構設計

This research proposes a structure of a 2D frequency shift microaccelerometer with good characteristics on linear response to respond the detected acceleration, high structure rigidity to resist influence from non-sensing axis acceleration, geometry symmetry to decouple a planar acceleration, and high sensitivity for sensing acceleration. In this design, the frequency shift principle, structure with symmetry geometry and also high-aspect ratio and the dimension optimization are adopted to fulfill the mentioned advantages. The results show that, the response linearity error for the simulated illustration is less than 4%, the deformation of the proof mass along gravitation direction is smaller than 0.01 µm, the cross-axis sensitivity is negligible less than 0.002%, and the sensitivity could be raised to 8%/G after dimension optimization. In addition, owing to the superior decoupling capability, the derived 1D analytical model can successfully calculate the sensed 2D planar acceleration. On the other side, the fabrication result of the adopted UV-LIGA process shows that, a 4 (w) × 20 (h) × 500 (l) µm nickel microbeam with high-aspect ratio 5 and slender ratio larger than 100 can be electroplated. In contrast to the previous design, the proposed 2D frequency shift microaccelerometer structure has a significant performance promotion and can be fabricated by using a simple and economic process.

[1] D.-H. Hwang, K.-P. Chin, Y.-C. Lo, and W. Hsu, "Structure Design of A 2D High-Aspect-Ratio Resonant MicrobeamAccelerometer." SPIE Journal of Microlithography, Microfabrication, and Microsystems 2005, 4, 033009.