Simulation and reliability assessment on high-g MEMS accelerometer under thermal stress

For high-g MEMS accelerometer in harsh temperature environment, the output failure due to large drift of piezoresistor is one of the main failure modes. In this paper, by simulating the thermal stress distribution of cantilever, chip structure and whole model after packaged, the structure beam was determined to be the most prone-to-failure area, and its maximum value was about 10⁷ N/m². By using the designed high-temperature accelerated constant stress test, the temperature dependence of silicon MEMS accelero- meter was verified. According to the characteristics of the testing data, three reliability assessment methods were used to quantitatively extrapolate its reliability index. The assessment results show that the accelerated degradation test and the reliability assessment method based on degradation amount are suitable for the high-g MEMS accelerometer in the temperature environmental, which can obtain high creditable assessment results only by using a part of test data.