论文部分内容阅读
Near eutectic Sn-Ag-Cu alloy,which is a promising lead-free solder coating,was electrodeposited from weakly acidic bath.As the interconnect density increases and the circuit current decreases in electronic systems,the reliability of electronic connectors has become more critical and it is important to investigate reliability of the Sn-Ag-Cu alloy coating.Corrosion resistances of Sn-Ag-Cu alloy coatings and growth of tin whiskers were studied.Corrosion current densities and corrosion potentials of Sn-Ag-Cu alloy coatings and Sn-37Pb alloy coating in 3.5mass% NaCl solutions were obtained from potentiodynamic polarization curves.Constant temperature and humidity experiments were employed to accelerate growth of tin whiskers.Scanning electron microscopy (SEM) was used to observe tin whiskers.The results of investigation indicate that corrosion resistances of Sn-Ag-Cu alloy coatings are as good as that of Sn-37Pb alloy,and tin whiskers easily grow on surface of Cu/Sn-Ag-Cu alloy coating.Two methods can inhibit the growth of tin whiskers,which are nickel preplating and electrodeposition of Sn-Ag-Cu-Al2O3 nano-composite coating.