ESD与短脉冲EOS失效的微观形态分析及验证

静电放电(ESD)和过电应力(EOS)是引起芯片现场失效的最主要原因,这两种相似的失效模式使得对它们的失效机理的判断十分困难,尤其是短EOS脉冲作用时间只有几毫秒,造成的损坏与ESD损坏很相似。因此,借助扫描电子显微镜(SEM)和聚焦离子束(FIB)等成像仪器以及芯片去层处理技术分析这两种失效机理的差别非常重要。通过实例分析这两种失效的机理及微观差别,从理论角度解释ESD和EOS的失效机理,分析这两种失效在发生背景、失效位置、损坏深度和失效路径方面的差异,同时对这两种失效进行模拟验证。这种通过失效微观形态进行研究的方法,可以实现失效机理的甄别,对于提高ESD防护等级和EOS防护能力有着重要的参考作用。

Micromorphology Analysis and Verification on ESD and Short Pulse EOS Failure

Electrostatic discharge (ESD)and electrical overstress (EOS)are major causes for field failures in integrated circuits.The similarity between EOS and ESD makes it very difficult to judge their failure mechanisms,especially for short EOS pulse duration of only a few milliseconds,resulting in damage similar to that of ESD.Therefore,it is very important to analyze the differences between the two failure mechanisms by means of advanced imaging equipment such as SEM and FIB,and advanced die delayering technology.The two failure mechanisms and the micro-differences between the two failure mechanisms were revealed through the analysis of practical examples.The failure mechanisms of ESD and EOS were explained theoretically,and the differences between the two failure mechanisms in the occurrence background,failure location,damage depth and failure path were analyzed,and then the two failures were simulated and verified.This method of failure micro-morphology study can realize the identification of failure mechanism and has an important reference for the improvement of the ESD protection grade and EOS protection capability.