Simulations of the impact of single-grained lead-free solder joints on the reliability of ball Grid Array components

The microstructure of lead-free solder joints often consists of only one or a few randomly oriented tin grains as a result of a large degree of undercooling during solidification. Due to the severe anisotropy of single crystal Sn and the random nature of the microstructure, the stress state and microstructural evolution of each joint will be unique.