对称体微机械电容加速度传感器的结构设计

STRUCTURE DESIGN OF SYMMETRIC BULK MICROMACHINING CAPACITIVE ACCELEROMETER

描述了一种用无掩模各向异性腐蚀技术制造对称体微机械梁质量块加速度传感器的结构。由于梁在质量块中心对称位置上，在结构上消除了加速度传感器的横向灵敏度效应。在对四梁结构及悬臂梁结构加速度计灵敏度及固有频率进行分析的基础上，用灵敏度频率积取优值的方法进行加速度计的结构参数优化。采用了一种新颖的微力微位移天平测试方法，初步测量了加速度计结构的静态特性。

OH silicon maskless anisotropic etching technology is adopted to fabricate a symmetric beammass structure accelerometer. Lateral sensitivity effect in conventional accelerometers is eliminated because the beams are located symmetrically to the middle of the seismic mass. Based on the calculation of sensitivity and basic resonant frequency of two kinds of bulk micromachining accelerometers, the structure parameters of cantilever and doublesidesupported accelerometer have been optimized by using the sensitivityfrequency product as the figure of merit of the structures. The different etching characteristics of 311 and 100 plane of silicon in KOH maskless anisotropic etching process have been utilized in the fabrication of the symmetric beammass structure. Preliminary measurement of the static characteristics of the structure has been performed with a forcedeflection balance measurement apparatus.