Wirebond Corrosion Failure of Plastic Packages in Extreme Environments: Theory and Experiment

Since the 1950s, and continuing to the present day, wirebond (WB) has remained the most popular interconnection technology. WB is known for its cost-effectiveness, proven reliability, and ease of processing. WB process has advanced significantly with modern developments, such as full automation and optimization of epoxy mold compounds (EMCs). However, mainstream CuAl WB contacts are susceptible to corrosion failures, triggered by the transport and localization of ionic species within the EMCs. The failure is primarily driven by applied bias but exacerbated by environmental factors, such as high relative humidity (RH) and temperature (T). In this scenario, a physics-based generalized failure model for WB corrosion has the potential to offer a robust and standardized qualification approach, streamline the testing process, and facilitate any future WB scaling. In this study, we: i) investigate the in situ ion migration behavior in the EMC using our proposed leakage current-based strategy; ii) simulate and analytically approximate the transient space charge accumulation in the WB-EMC interface; iii) integrate the insights from the simulations and the assumption of a first-order redox reaction into a failure distribution model; and iv) validate the model with integrated circuit (IC) failure data from accelerated tests. The resulting model would serve as a versatile predictive tool for qualifying WB technology.