Stochastic simulation of electromigration failure of flip chip solder bumps
Stochastic simulations are performed for the first time to explore the nature of electromigration failure of SnPb flip chip solder bumps at room temperature. Treating the SnPb flip chip solder bump as a random resistor network and electromigration as a diffusion-controlled depletionaccumulation process, the main features of limited experimental observations are well reproduced. The microstructure and current density dependence of the time to failure, the median time to failure and the dynamics of void/hillock growth, as well as the electromigration-induced resistance fluctuations are obtained to provide a comprehensive interpretation of electromigration process and failure in terms of physical parameters in SnPb solder bumps. The approach introduced in the present work can be used for elucidating the most important factors in controlling the electromigration and its rate of flip chip solder bumps, and thus contribute to their optimal design.
stochastic simulations electromigration flip chip snpb solder bumps