Effect of surface pad finish on fracture mode of flip chip package under electro-migration

Electro-migration effect in Cu-OSP and ENIG pad finish in flip chip package were investigate. A temperature of 398 K with a current density of 1.5×10
⁴
A/cm2 was applied. For EM phenomena were investigated using SAC solder composition of different pad finish. The diameter of the bumps was about 100 mm. Through this research, the main fracture types can be represented by two types : 1) failure caused by voids in the solder; 2) failure caused by Cu wiring. And the movement of Sn, Ag and Cu atoms in solder bump were able to confirm.