Effect of Ga/Nd composite additive on the wettability and microstructure of low silver Sn-Ag-Cu solder

The effect of Ga/Nd composite additive on the wettability and microstructure of n-0.3Ag-0.7Cu solder were investigated.The results indicated that the composite additive of Ga and Nd could greatly improve the wettability of solder, the optimal wettability of solder was obtained when the addition of Nd reached 0.1 wt.%. After adding moderate amount of Ga and Nd, the microstructure of solder was refined andthe shear strength of soldered joint was improved by 15%. Compared with the previous results that excessive amount of Nd was added, no obviously Sn-Nd phase observed in the solder, indicating that the composite additive of Ga and Nd could inhibit the formation of Sn-Nd phase to a certain extent.