MEMS加速度计在振动环境下的可靠性分析

Reliability Analysis of MEMS Accelerometer in Vibration Environment

摘要:

以电容式MEMS加速度计的悬臂梁结构为研究对象,分析了振动环境下MEMS加速度计的典型失效模式及失效机理；在Miner理论的基础上,引入了应力-寿命曲线,建立了疲劳可靠性模型；在考虑强度退化前提下,基于应力强度干涉理论建立了塑性形变可靠性模型；运用蒙特卡洛法验证了两种可靠性模型的准确性,并分析了模型关键参数对可靠度的影响。结果显示,振动应力水平和材料的屈服强度对可靠度有显著的影响,减小应力幅值,增大屈服强度,可以提高MEMS加速度计的可靠性。

Abstract:

Taking the cantilever structure of capacitive MEMS accelerometer as the research object, the typical failure mode and failure mechanism of MEMS accelerometer in vibration environment were analyzed. Based on Miner's theory, the stress-life curve was introduced to establish the fatigue reliability model. The reliability model of plastic deformation was established based on stress intensity interference theory considering strength degradation. The Monte Carlo method was used to verify the accuracy of the two reliability models, and the influence of the key parameters of the model on the reliability was analyzed. The results show that the vibration stress level and the yield strength of the material had significant influence on the reliability. Reducing the stress amplitude and increasing the yield strength can improve the reliability of the MEMS accelerometer.