Effects of silver doping on electromigration of eutectic SnBi solder

Effects of silver doping on electromigration behavior of the eutectic SnBi solder are investigated. Electromigration can induce the Bi migration along with the direction of electron flow in the eutectic SnBi solder, thus Bi depletes at the cathode side but accumulates at the anode side. Plate-like Ag3Sn compound is formed as 0.5 wt% silver is doped into the solder. The Ag3Sn plates behave like roadblocks which can intercept the Bi migration from the cathode side to the anode side. Consequently, a great inconsistency is found between the Bi depletion at the cathode side and the Bi accumulation at the anode side.