MEMS开关的失效模式及机理的分析

Failure mode and mechanism of a MEMS relay

主要探讨了微电子机械系统中普遍存在的失效模式及机理,对几种没有明确对应模式的失效机理也做了介绍。最后针对一种具体的微机械开关器件,研究了它的可靠性问题,给出了相应的可靠性提高措施。该微机械开关主要受限于两种失效模式,其中结构粘附主要发生在结构释放工艺,大大降低了成品率;而金属接触电极之间的压降引起的电弧现象,则对开关的工作寿命形成了严重限制。通过对几种结构释放工艺的比较,指出SCCO2是最佳的释放措施,并比较了几种不同的金属接触电极以降低电弧效应。该微机械开关的工作寿命已由初期的106开关次数提高到了普遍高于108开关次数。

The prevalent failure modes and mechanisms of MEMS are introduced in the paper,as well as some failure mechanisms with no counterpart modes.For the purpose of a high relia-bility and long lifetime micro relay,the failure modes and mechanisms of the relay are analyzed.Among them,two dominant failure modes are discussed.Stiction usually occurs during the struc-ture re lease process and constrains the yields very much,while arcs between contact pads caused by voltage drops impose a vital issue on lifetime of the relay.Several release processes are com-pared,as the results,SCCO2release is the best of all.Contact electrodes with different metals are com pared and tested to weaken arc effects.The lifetime of the relay is about 10 8 times now while it was about 10 6 times before.