Study on the thermal stress of MEMS high-g accelerometer in the package

Thermal stress in the package is one of factors that lead to the failure of MEMS device. A MEMS highg accelerometer was designed, at the same time, thermal stress and the factors which effect thermal stress was simulated during the sensor packaging prosess in this paper. According to packaging technology, the finite element model of high-g accelerometer package was built by ANSYS software and thermal stress was simulated in the different joining technology. The results show that thermal stress can be reduced from 135 MPa to 33 MPa by comparison with directly patch to the bottom of the shell when it bonded with the glass. In the joining technology, the thermal expansion coefficient of the substrate and elastic modulus, thermal expansion coefficient and the thickness of the adhesive are the main factors that would effect the thermal stress ; In the bonding process, the substrate and the bonding temperature mainly effect the thermal stress.