Electrochemical migration failure mechanism and dendrite composition characteristics of Sn96.5Ag3.0Cu0.5 alloy in thin electrolyte films.

The effects of chloride ions on electrochemical migration (ECM) of Sn96.5Ag3.0Cu0.5 (SAC 305) solder alloy are studied through in situ electrochemical observation device and ex situ transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS) techniques. The results show that the time to short circuit is the longest at intermediate NaCl concentration, which is related to the precipitates between two electrodes. The composition of dendrite inspected by TEM-EDS and XPS techniques shows that dendrites do not contain elements Ag and Cu, which suggests that Sn is the only migration element in SAC 305 alloy. [ABSTRACT FROM AUTHOR]