Effect of Phase Evolution on Inhomogeneous Deformation and Fracture Behavior in Sn-Bi Solder Alloys

Sn-Bi based low-temperature solders used for high-density heterogeneous integration has attracted widespread attention in recent years due to its many advantages and low-cost. However, the microstructure characteristic of the Sn-Bi solder matrix has an increasingly significant impact on the interconnect performance and reliability as the packaging density increases. In this study, a developed phase field model is employed to study the deformation and fracture behavior of Sn-Bi eutectic solder alloy. It is found that the phase distribution characteristics greatly affect the fracture path and crack growth rate, and the cracks mainly propagate along the Bi-rich phase. The phase segregation and separation of Sn-Bi solder have an important impact on the mechanical properties and failure characteristics.