Enhanced Shear Strength of Sn-Bi/(111)Cu Joints by Refined Distribution of Bi in the Composite Solder.

In recent years, Sn-Bi solder has been widely used in the electronic packaging industry due to its low melting point. However, the segregation and coarsening of Bi will degrade the mechanical properties of solder joints. In this paper, the shear strength of Sn-Bi/(111)Cu joints is enhanced by refining the distribution of Bi in the composite solder. Bi diffuses in the Sn-Sn58Bi layered composite structure in the reflow process, resulting in inhibition of coarsening. In addition, the growth behavior and orientation of Cu₆Sn₅ in Sn58Bi/(111)Cu and Sn-Sn58Bi/(111)Cu solder joints are also investigated. [ABSTRACT FROM AUTHOR]