Effect of Nd on whiskers growth behavior of SnAgCu solders in electronic packaging

The effects of rare earth Nd on the whisker growth were investigated, it is found that the presence of Nd causes the risk of whisker growth due to the oxidation of RE-rich NdSn3 intermetallic compounds. The relationships between average diameters of NdSn3, Nd contents, storage time, storage temperature and the whisker were tested, the oxidation mechanisms were selected to expound the whisker growth behavior. The compressive stress induced by volume expansion during oxidation procedure was suggested as the driving force for the growth of whisker in SnAgCu-xNd lead-free solders.