Effect of Al-trace degradation on Joule heating during electromigration in flip-chip solder joints

Abstract

This study investigates the mechanism for the abrupt increase in temperature at later stages of electromigration in flip-chip solder joints. It is found that electromigration also occurs in Al traces when stressed by 0.6A at 100°C. Three-dimensional thermoelectrical simulation by finite element analysis was carried out to simulate the temperature distribution in solder joints with and without degradation of the Al trace. It is found that the degradation of the Al trace has substantial effect on the Joule heating of solder joints. This model can explain the serious Joule heating effect in the later stages of electromigration.