Plastic characterization and performance of SnAgCuBiNi/Cu lead-free BGA solder joints

Nanoindentation test is performed on study the plastic and creep properties of the Sn-Ag-Cu（SAC） lead-free ball grid array（BGA） solder joints.The dynamic hardness of two kinds of solder joints decreases with indentation depth increase.SAC0705BiNi/Cu exhibits a higher ultimate dynamic hardness and a smaller indentation depth than SAC305/Cu.Then the strain hardening phenomenon of SAC305/Cu is more obvious compared to that of SAC0705BiNi/Cu.The indentation creep of SAC0705BiNi/Cu solder joint is lower than that of SAC305/Cu solder joint before and after thermal shock.The creep rate sensitive index of SACBiNi/Cu solder joint is lower than that of solder joint.SAC0705BiNi/Cu solder joint is superior to SAC305/Cu solder joint in the anti-creep property.The plasticity of SAC0705BiNi/Cu and SAC305/Cu solder joints are similar.Compared with SAC305 solder,the SAC0705 BiNi solder performs higher hardness and solder creep resistance and still maintains a good plasticity.