Interfacial Reactions between Sn-Ag-Cu-Fe Composite Solder and Cu Substrate

Abstract

The growth kinetics and morphology of intermetallic compound (IMC) between Sn-3Ag-0.5Cu -xFe (x= 0, 0.5wt.%, 1wt.%) composite solders and Cu substrate were investigated in the present work. The Sn-Ag-Cu-Fe/Cu solder joint were prepared by reflowing for various durations at 250°C. During soldering process, Fe particles quickly deposited in the vicinity of IMC, resulting in the formation of Fe-rich area. It was shown that Fe could effectively retard the growth of interfacial Cu6Sn5 and Cu3Sn layers during liquid-state reaction and reduce the size of Cu6Sn5 grains. Small cracks were observed in the Cu6Sn5 grains of Sn-Ag-Cu/Cu interface after reflowing for 30 min while they were not found in the other composite solders.