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非硅MEMS惯性开关具有体积小、成本低、可批量生产以及强度和导电性能较好的优点,但其可靠性问题制约了其应用领域。通过开展非硅MEMS惯性开关的可靠性实验(包括温度循环实验和随机振动实验),找出其主要失效模式为分层。通过对失效部位进行分析,并利用有限元方法分析器件上的应力分布,研究了相应的失效机理。研究结果表明:引发惯性开关分层失效的主要原因是层间产生疲劳效应,温度循环应力会使惯性开关各层间由于热膨胀系数失配而产生疲劳,而振动应力则直接加载在惯性开关上而使其产生疲劳;惯性开关中铬层与铜层之间最易发生失效,而分析表明该层间界面处热应力最大;经历温度循环实验和振动实验的惯性开关相较只经历一种实验的样本更容易失效,进一步说明了温度循环应力会使开关层间发生疲劳,而振动应力则会引起应力集中而加速分层失效。
Non-silicon MEMS inertial switch with small size, low cost, mass production and good strength and conductivity advantages, but its reliability issues have restricted its application. Through the reliability experiment of non-silicon MEMS inertial switch (including temperature cycling experiment and random vibration experiment), the main failure mode of the non-silicon MEMS inertial switch is delamination. By analyzing the failure site and using finite element method to analyze the stress distribution on the device, the corresponding failure mechanism is studied. The results show that the main reason of inertia switch delamination delamination is fatigue between layers. Temperature cycling stress will cause fatigue of all layers of inertial switch due to mismatch of thermal expansion coefficient, while vibration stress is directly loaded on inertial switch The inertia switch is the most prone to failure between the chromium layer and the copper layer, and the analysis shows that the thermal stress at the interface between the layers is the largest. The inertia switch subjected to the temperature cycling experiment and the vibration experiment only experiences one kind of experiment Samples are more likely to fail, further illustrating that cyclic temperature stress causes fatigue between switch layers, whereas vibration stress causes stress concentration and accelerates delamination failure.