Electrochemical impedance spectroscopic studies of copper dissolution in arginine-hydrogen peroxide solutions

Anodic dissolution of copper in arginine and hydrogen peroxide-based medium suitable for chemical mechanical planarization slurry formulation was investigated using electrochemical impedance spectroscopy. Potentiodynamic polarization and impedance data were acquired for copper dissolving in hydrogen peroxide and arginine solution. Reaction mechanism analysis (RMA) was employed to determine the mechanistic pathway of copper dissolution. RMA analysis indicates that a stable passivating film does not form on the copper surface, and the direct dissolution of copper was also ruled out. A two-step mechanism involving cupric oxide as an intermediate species is proposed. The data were also fit to an electrical equivalent circuit to obtain insight into the variation of the parameters with the overpotential. The modeled data for the two-step mechanism captures the essential features of the impedance spectra at various overpotentials.