The behavior of impurities during copper electrodeposition

Abstract

The behavior of impurities (in particular arsenic, antimony and bismuth) on copper electrodeposition was investigated using several non-steady state techniques at a temperature of 63°C in cupric sulfate solution (Cu 45 g/l, H₂SO₄ 200 g/l). As a result, group-V elements work as depolarizers against copper deposition and hydrogen evolution. From the result of cyclic voltammetry, copper reduction was subject to an irreversible reaction with a preceding chemical reaction. In general, copper deposition is not significantly effected by group-V impurities at the compositions investigated. Basic electrochemical parameters, except for the transfer coefficient, were also insensitive to these impurity constituents. However, there is a peak due to arsenic reduction (at -0.330 V) in cyclic voltammogram for the As-containing electrolyte. In addition, the effect of impurities on morphologies were investigated by SEM observation and X-ray diffractometry. As a result, group-V promoted truncated deposits and the (110) crystallographic orientation.