Reliability analysis on electromigration and electro-thermo-mechanical for Sn4.0Ag0.5Cu solder ball

An electro-thermo coupling finite element model for lead free Sn4.0Ag0.5Cu (SAC405) solder ball is developed to investigate the electromigration and electro-thermo-mechanical effects on electronic packaging in the present paper. SAC405 alloy solder ball are commonly used on BGA package and POP package. In this research, a single solder ball (bump) used on flip chip package is established to evaluate electro-thermo response as the electricity is connected. Preliminary results shown that current density arising in the Copper trace above SAC405 solder ball implies the hot spot where results in an electromigration along the current flow direction. Finite element predictions reveal the peak electro-thermo-mechanical effective stress is located at the regions where electromigration potentially occurred. Current crowding, temperature distribution and electro-thermo induced effective stress distribution are predicted. A submodel scheme is applied for evaluation of equivalent life time of these lead free solder balls. In this paper, reliability analysis on electro-thermo-mechanical for SAC405 solder ball is also evaluated.