Resistance characterization of Cu stress-induced void migration at narrow metal finger connected with wide lead

In this work, copper stress-induced voiding (SIV) at narrow metal finger connected with wide lead is investigated. Three failure modes are explored and discussed with different failure sites. A driving force for void migration resulted from hydrostatic stress gradient is also studied. Meanwhile, in order to assess the impact of copper void on multi-level interconnects, a model based on finite element analysis (FEA) is developed to simulate the resistance change with regard to voiding location, void morphology and interconnect scenario. Finally, a correlation between SIV and resistance change is obtained, which can serve as references for reliability evaluation and risk assessment.