金属迁移致LED漏电失效实验研究

Experimental Study on Leakage Failure of LED Caused by Metal Migration

通过实验还原了失效LED产品,利用I-V曲线测试仪研究了失效LED产品的漏电规律,通过X-Ray探测仪和光学显微镜(OM)检测了失效LED产品内部形貌差异,采用扫描电子显微分析仪(SEM)和能量色谱X射线光谱仪(EDX)测试分析了失效LED产品的微观组织形貌以及组成成分,确定了LED产品失效原因。实验结果表明:在外加电压作用下,金属元素在PN结之间会发生迁移,造成LED漏电失效;PN结由于漏电发热,导致Au电极和芯片结合力变差,发生电极脱落和芯片烧伤现象。因此可对芯片表面进行纳米涂层设计,能有效地防止金属迁移。

In this experiment,the failed LED products were reproduced.The leakage law of the failed LED products was studied by I-V curve tester.The difference of the internal morphology of the failed LED products was detected by X-ray detector and optical microscope(OM).The microstructure and composition of the failed LED products were analyzed by scanning electron microscope(SEM)with energy dispersive X-ray spectrometer(EDX).The failure causes of LED products were determined.The experimental results show that:under the action of the applied voltage,metal elements migrated between the PN junctions,resulting in LED leakage failure.Owing to the leakage heat,the PN junction deteriorated the bonding force between the Au electrode and the chip,and the electrode fell off and the chip burned.Therefore,nano coating can be designed on the chip surface,which can effectively prevent metal migration.