The effect of chloride ion concentration on electrochemical migration of copper

The effect of chloride ion concentration of electrochemical migration (ECM) was investigated on copper applying in situ electrochemical, optical and scanning electron microscopy—energy dispersive X-ray spectroscopy methods. An unexpected phenomenon was found: copper dendrite grows not only at low chloride concentration, but also at high and even saturated chloride concentrations, although it is generally suggested that the growth of copper dendrite through ECM does not take place in high chloride concentration solutions. Reactions have been proposed to explain the ECM of copper under different chloride concentration levels.