Investigation of Potting-Adhesive-Induced Thermal Stress in MEMS Pressure Sensor

Sensors

卷:21

Feng Li¹  Wentao Ni²  Bowen Li²  Yunfan Zhang³  Hui Li³  Shengnan Shen³  Wan Cao⁴ 

[1] School of Electrical and Electronic Engineering, Wuhan Polytechnic University, Wuhan 430023, China;

[2] School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072, China;

[3] The Institute of Technological Sciences, Wuhan University, Wuhan 430072, China;

[4] Wuhan FineMEMS Inc., Wuhan 430075, China;

关键词: MEMS pressure sensor;    potting adhesive;    thermal stress;    output error;   

DOI  :  10.3390/s21062011

来源: DOAJ

【 摘 要 】

Thermal stress is one of the main sources of micro-electro-mechanical systems (MEMS) devices error. The Wheatstone bridge is the sensing structure of a typical piezoresistive MEMS pressure sensor. In this study, the thermal stress induced by potting adhesive in MEMS pressure sensor was investigated by experiments, calculated by analytics and analyzed by simulations. An experiment system was used to test the sensor at different air pressures and temperatures. The error becomes greater with the decrease in pressure. A set of novel formulas were proposed to calculate the stress–strain on Wheatstone bridge. The error increases with the temperature deviating from 25 °C. A full-scale geometric model was developed, and finite element simulations were performed, to analyze the effect of the stress on MEMS pressure sensor induced by different temperatures and thicknesses of potting adhesive. Simulation results agree well with the experiments, which indicated that there is a 3.48% to 6.50% output error in 0.35 mm potting adhesive at 150 °C. With the thickness of potting adhesive increasing, the variations of output error of the Wheatstone bridge present an N-shaped curve. The output error meets a maximum of 5.30% in the potting adhesive of 0.95 mm and can be reduced to 2.47%, by increasing the potting adhesive to 2.40 mm.

【 授权许可】

Unknown