Interface reaction and properties of Sn3.5Ag0.5Cu-xNd solder joints subjected to isothermal aging

Abstract

In this paper, rare earth Nd with various contents (0, 0.04 and 0.5 wt.%) was incorporated into Sn3.5Ag0.5Cu (SAC) solder. The influence of rare earth Nd on the interface reaction, microstructure development, mechanical behavior and wettability were investigated by scanning electron microscopy (SEM), joint strength measuring instrument, and wetting balance method. Adding a small amount of Nd can suppress the growth of interface IMC layer and subdivide the joint microstructure. The mechanical behavior and wettability were also improved efficiently. In the N2 atmosphere, the wettability of solder is better. In addition, the mechanical behavior of three kinds of solder joints decreases with increasing aging time, but the degree of decline of 0.04Nd solder joint is relatively slow.