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

Abstract

Electromigration in eutectic SnPb has been studied at the device temperature i.e. 100/spl deg/C and at three different current densities viz. 5/spl times/10/sup 3/ A/cm/sup 2/, 5/spl times/10/sup 4/ A/cm/sup 2/ and 5/spl times/10/sup 4/ A/cm/sup 2/. 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/spl times/10/sup 3/ A/cm/sup 2/ and 5/spl times/10/sup 4/ A/cm/sup 2/ current densities. The dominant diffusing species is found to be Pb in both cases. At 5/spl times/10/sup 3/ A/cm/sup 2/, 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.