Effect of Incorporation of Ceramic Nanoparticles in Bismuth-Tin Solder Paste on Electrochemical Migration

This work aimed to investigate the susceptibility of novel nanocomposite solder paste to electrochemical migration (ECM). Bismuth-tin solder paste was filled with 0.1 wt.% of $\mathrm{T}\mathrm{i}\mathrm{O}_{2}$ nanoparticles. The electrochemical migration behavior was evaluated using a water drop (WD) test. High-purity water and 10 VDC bias voltage were applied. The experiments were performed on two types of samples differing in the surface finish of conductive pattern- bare copper without surface protection and copper with applied galvanic gold finish. The results revealed a trend when the mean time to failure decreased for samples with deposited nanocomposite solder paste, regardless of the surface finish. Thus, the electronics’ reliability may be lowered when using Bi-Sn paste doped with $\mathrm{T}\mathrm{i}\mathrm{O}_{2}$ nanoparticles, at least in terms of ECM. This deterioration of the solder paste should be considered a significant drawback for further development. However, the nanoparticles could improve other properties related to modified microstructure, such as mechanical or thermal. These aspects will be the subject of further research.