SEM study on the mechanism of electromigration induced Sn alloy solder joints failure

Electromigration of a solder joint structure will cause the joint to fail, leading to a short or open circuit and reducing package life. It is important to clarify the damage mechanism of electromigration and explore ways to extend the life of solder joints to improve reliability of electronic packaging structures. Current research on solder joint failure mainly focuses on fracture, creep, and interface cracking caused by thermal cycling. There is relatively little research on the accumulation of solder joint vacancies caused by electromigration and the mechanism of crack nucleation. The formation of voids is important in the study of micro-solder joint failure. Meso-damage mechanics analysis combined with numerical simulation was applied to the analysis of electromigration failure, to establish the criterion for formation of electromigration voids in solder joints. The effectiveness of using this method was verified by comparison of the calculated time for formation of electromigration voids in the solder joints with that of experimental results.