Current stressing-induced growth of Cu3Sn in Cu/Sn/Cu solder joints

We investigated the influence of current stressing on a crystallographic microstructure of intermetallics in Cu/Sn/Cu solder joints using electron backscatter diffraction (EBSD). After direct current (DC) stressing at 150 °C for 10 d, the total Sn of the Cu/Sn/Cu was converted into a tri-layer structure of Cu3Sn/Cu6Sn5/Cu3Sn. The Cu3Sn layers that grew on the cathode and anode are asymmetrical during DC stressing. A preferred direction < 010> Cu3Sn along the current direction on the anode was found after current stressing.