A study on protection behavior of inorganic coating prepared by magnetron sputtering technology for electrochemical migration corrosion failure of SAC305 alloy

Abstract The electrochemical migration (ECM) problem caused by corrosion is one of the most serious threats to the reliability of electronic equipments in a harsh condition. In this paper, the Al2O3, TiO2 and ZrO2 inorganic coating with a thickness of 1 μm deposited by magnetron sputtering technique are used to protect SAC305 solder alloy against ECM corrosion failure. Then the surface topographies, surface roughness and thickness of the coating are observed through atomic force microscopy and scanning electron microscopy. The thin electrolyte film containing chloride experiments are used to simulate the marine atmospheric environment to inspect the protection performance of the coatings. The results show that these coatings can inhibit ECM process and extend the time to short circuit to some extent. Specifically, TiO2 has the most excellent protective properties, followed by ZrO2. Moreover, the protection performances of these coatings are also further compared through adsorption energy of chloride on the coatings surface calculation, and the result indicates that Cl− is more easily absorbed on the surface of Al2O3, which also implies that the Al2O3 has poorer protection property than TiO2 and ZrO2.