Electromigration Effects in Corroded BGA

Most reliability or qualification tests focus on a single type of failure mechanism, whereas in the field, the devices are submitted to sequential and superimposed loads. In this paper, the influence on electromigration sensitivity due to corrosion of SAC solder joints is evaluated by finite element simulations. In comparison to new solder joints, the corroded zones induce a change in the weakest part location. Moreover, the maximum electromigration mass flux divergence of corroded bumps is approximately 35% higher than the normal solder bump, which means the electromigration performance is getting worse because of the corrosion. Moreover, the thermomigration effect is also worsened by the corrosion.