Electromigration Time to Failure Simulation for Solder Bumps of a Chip Scale Package

This paper studies the numerical simulation method for electromigration in the solder joint of a chip scale package. The three dimensional electromigration finite element model for solder joint reliability is developed. Numerical experiments are carried out to obtain the electrical, thermal and stress fields with the migration failure under high current density loads. The indirect coupled analysis that includes electrical, thermal and stress fields are investigated and discussed. The viscoplastic and constitutive material model with both SnPb and SnAgCu solder materials is considered in the paper. The sub-model technique is studied with indirect coupled multiple fields. The impacts of geometry parameters, which include ball shape, trace width and UBM diameter for void formation and electromigration time to failure (TTF) are finally investigated.