Research Progress on Electrochemical Migration Failure of Tin-based Solder Alloys

With the rapid advancement of electronic packaging technology toward high-density integration and fine-pitch interconnection, the drastic reduction in solder joint spacing leads to a significant increase in local electric field strength. Under the combined influence of environmental moisture and ionic contaminants, electrochemical migration (ECM) failure is readily triggered, posing a serious threat to the long-term service reliability of electronic devices. This paper first outlines the fundamental mechanism of ECM, compares the mechanistic differences between conductive anodic filament growth and dendrite formation, and summarizes the advantages and limitations of commonly used accelerated testing methods such as temperature-humidity bias testing and the water drop test. Subsequently, the effects of key factors including bias voltage, dust contaminants, flux residue, and alloy composition on the anodic dissolution, ion migration, and dendrite growth behavior of solder alloys are discussed in detail. Finally, the paper summarizes feasible strategies for suppressing the electrochemical migration of tin (Sn)-based solders, including alloy modification, the addition of corrosion inhibitors, and the use of pulsed or alternating voltage regulation. It also provides an outlook on future research priorities and trends in this field based on the current state of knowledge.