Mn based self-aligned diffusion barriers are promising for incorporation in the copper interconnects designed for the ≤22 nm technology node. However, in the current metallization scheme of chemical mechanical planarization (CMP), the processing of these barrier lines presents a specific challenge, which is rooted in the intrinsic corrosion characteristics of the Cu-Mn bimetallic couple. Since the Mn component of the self-aligned barrier film is electrochemically active compared to its adjacent Cu lines, the Cu-barrier interface of such a device tends to galvanically corrode in the chemical slurries used for CMP. Employing electrochemical techniques and a model galvanic system of polycrystalline Mn and Cu electrodes, the present work focuses on developing a strategic chemical approach to controlling this corrosion. The results demonstrate that, in the alkaline slurry environment (pH = 9–12, frequently used for barrier-CMP), a relatively low concentration (0.5 mM) of salicylaldehyde can minimize the galvanic corrosion of Mn while maintaining the latter's CMP-specific surface activity. The underlying mechanisms of these effects are probed with open circuit potential measurements, voltammetry and impedance spectroscopy.