Abstract:The morphology evolution of intermetallic compounds (IMC) in Cu/SnBi/Cu solder joint after current stressing at the current density of 8×103, 1×104 and 1.2×104 A/cm2 for 80 h was investigated. Results indicate that when the current density was 8×103 A/cm2, a lot of irregular-shaped IMCs were observed at the anode interface; however, there was no obvious IMC formation at the cathode interface. When the current density was 1×104 A/cm2, scallop-shaped IMC layer was formed at the cathode interface, and some of them had spalled from the interface; while at the anode interface, the lamellar IMC was formed, and it was thinner than that at the cathode interface. When the current density was 1.2×104 A/cm2, the thickness of the IMC layer at the anode interface increased. Nevertheless, the IMC at the cathode interface had diffused and migrated towards the solder matrix, which made the cathode interface uneven. It should be noted that, with the current density increasing, the thickness of Bi layer forming at the anode side increased greatly