Electromigration in eutectic tin-lead solder lines at the device temperature

Electromigration in eutectic SnPb has been studied at the device temperature i.e. 100°C and at three different current densities viz. 5×10³ A/cm², 5×10⁴ A/cm² and 5×10⁴ A/cm². The test samples are prepared by reflowing solder into V-grooves etched on [001] Si wafer. The accumulation of a large lump of solder is observed at the anode for 5×10³ A/cm² and 5×10⁴ A/cm² current densities. The dominant diffusing species is found to be Pb in both cases. At 5×10³ A/cm², the electromigration doesn´t occur. The effects of current stressing on microstructure of eutectic SnPb solder have also been reported. Grain coarsening is observed, which becomes very significant with increasing current density.