Reliability study in solder joint under electromigration and thermal-mechanical load

This paper presents a numerical study of electronic migration in solder joint under the interaction of high current density, thermal load and mechanical load. Three dimensional finite element model of a flip chip solder joint structure is developed and tested through numerical experiment. An improved algorithm of void formation and propagation in solder joints has been developed with consideration of electro-migration, thermo-migration and stress-migration. The improved algorithm is based on direct couple analysis that includes electrical, thermal and structural fields. The time to failure life predictions due to mass migration have been simulated based on the voids, current density, temperature and mechanical stress distribution. Numerical simulation has shown that the failure life of the electronic migration under the interaction of high direct current density, thermal loads and mechanical loads is far smaller than that of the electric-thermal coupling migration without considering stress-migration.