The wettability and interfacial reaction between Sn-3.5Ag solders and Cu-substrate were examined as a function of alloying element (1Pb, 1Sb) and soldering time. Cu/solder joints were subjected to aging treatments for up to 60 days at 150˚C to observ...
The wettability and interfacial reaction between Sn-3.5Ag solders and Cu-substrate were examined as a function of alloying element (1Pb, 1Sb) and soldering time. Cu/solder joints were subjected to aging treatments for up to 60 days at 150˚C to observe interfacial compounds and changes of microstructure by optical microscopy, SEM and EDS. The addition of 1Pb to the Sn-3.5Ag solder improves the wetting characteristics of the alloy and lowers the melting temperature. The growth rate of the Cu_6Sn_5 layer in the Sn-3.5 Ag solder/Cu was faster than that in the Sn-3.5Ag-1Sb solder/Cu. The activation energy for Cu_6Sn_5 growth was estimated as 31∼35 kJ/mole. (Received January 15, 1999)