Effect of electric pulse auxiliary reflow soldering on the microstructure and properties of Sn58Bi/Cu solder joints

The demand for high-computing-power AI chips in the consumer electronics market is driving the development of electronic packaging technology toward high-reliability packaging. The application of low melting point solder Sn58Bi in high-reliability 3D packages is currently facing issues of low toughness and poor in-service reliability. A new strategy differentiating the alloying of conventional solders has been proposed, which produced solder joints with improved microstructure and properties through electric pulse auxiliary reflow soldering of Sn58Bi/Cu solder joints. The electric pulse resulted in Bi-rich phases and different morphologies of pre-eutectic Sn in the solder joints via the incubation effect, improving the shear strength of the solder joints. This research provides a new strategy for improving the strength and reliability of Sn58Bi solder joints in advanced electronic interconnection.