Package reliability of MEMS sensors used in automotive under random vibration

The package and interconnection are critical concerns that influence the reliability of MEMS sensors applied in modern automotive under random vibration conditions. This paper conducts a research on this problem to reveal the reliability and influencing factors of MEMS on board level using finite element modelling and random vibration response simulation method. The ADXL78 MEMS chip is used as an example. Model analysis has been used to obtain the frequency character of MEME sensor. The loading is power spectral density of different pavement levels obtained from Belgium pavement test in GB/T 7031- 2005 (Mechanical vibration-road pavement spectrum measurement data report). Random Vibration analysis has been used to obtain the solder joint maximum equivalent stress of ADXL78.The results show that the MEMS package solder joint is the weakness point in the structure to fatigue failure. The engineering design and application suggestions for improving the packaging reliability of MEMS are presented through the sensitive factors analysis.