Application of Electrochemical Impedance Spectroscopy (EIS) to Study the Effect of Temperature and Ion Concentration During Electroplating of Copper from an Acidic Bath

In the present investigation, copper electrodeposition from an acidic bath at low temperature and varying copper ion concentrations has been studied by using electrochemical impedance spectroscopy (EIS). A fitted equivalent circuit was utilized to determine EIS parameters. Double-layer capacitance ( C dl ) values for 0.1 M and 0.5 M Cu concentrations are 90 and 82 μF, whereas Gouy–Chapman capacitance ( C diff ) at constant potential values is 55 and 122 μF. The C dl values ranged from 44 to 87 µF as the temperature increased from 5 to 25 °C, while the C diff values extended from 112.76, 105.4, 98.66, 92.53 and 86.96 μF. It was found that the diffusion coefficient ( D ) values increased with temperature and low molar concentration of Cu. The value of electrochemical activation energy was obtained to be 35.19 kJ/mol. The obtained copper deposits were studied by atomic force microscopy (AFM) and scanning electron microscope (SEM). It was observed that the deposits were denser and adherent at low temperatures and all concentrations.