基于MEMS技术的金属应变式压力传感器优化设计

Optimization Design of Mental Strain Pressure Sensor Based on MEMS Technology

文中从金属应变式压力传感器的基本理论出发，以硅弹性膜铂应变电阻压力传感器为原型，推导了圆形和方形弹性膜片上电阻的变化率（dR／R）公式。通过比较，选用方形弹性膜为压力承压膜，以优化承压膜的宽厚比为出发点，用有限元方法对不同厚度方形膜片（宽度为2mm）进行应力分析。由硅材料的屈服应力与最大位移的限制，确定了最优的膜厚范围；根据有限元仿真的结果对压力传感器进行优化设计，对所做压力传感器芯片进行测试，在6．00×10^4-1．06×10^5Pa的范围内，其精度优于50Pa．

According to the basic theory of mental strain pressure sensors, this paper selected the flexible silicon membrane platinum resistance strain pressure sensor as a prototype, deducing the formulas of resistance change rate （dR/R） of circular and square elastic membrane. By comparing, this paper adopted square elastic membrane as pressure accepted membrane and used finite element method to analyze stress of different thick membrane in order to optimize the wideness-thickness-rate of pressure accepted membrane. Because of the limitation of yield stress of silicon material and maximum displacement, it obtained the optimal range of thickness. According to the result of finite element simulation, the design of pressure sensor was optimized. The pressure sensor chip is tested from 6.00 × 10^4 Pa to 1.06 × 10^5 Pa,its precision range is within 50 Pa.