We observed abnormal electromigration-induced Cu depletion in a traditional line-bump-line (Cu/Sn/Cu) solder joint with extremely high Cu depletion away from the current crowding region (CCR). Electron backscatter diffraction analyses showed that the beta-Sn crystallographic orientation of the solder alloy is responsible for this abnormal electromigration phenomenon. A pronounced depletion in Cu occurred when the Cu neighbored the Sn grains with c-axes parallel to electron flow, despite the fact that the current density distributed in this type of area was one order-of-magnitude lower than that of the CCR. This observation indicated that the current stress and beta-Sn crystallographic orientation played dominant roles in Cu depletion during electron current stressing. Finally, a new failure mechanism is proposed for electromigration in solder joints. (C) 2015 Elsevier B.V. All rights reserved.