The dissolution of copper in monoethanolamine (MEA)-complexed cupric ion solution containing different additives was studied. Bridging ligands, such as F-, Cl-, Br-, I-, SCN-, and oxidizers, including S2O82-, Cr2O72-, MnO4- were added to this nonammoniacal etching solution to increase the copper dissolution rate. Potentiodynamic methods were employed to elucidate the dissolution mechanism and the corrosion potential (E-corr) was found to shift from 10 to 90 mV as opposed to that of the original solution (0.045 M cupric sulfate and 0.225 M MEA) for bridging ligands. In contrast, some conventional oxidizers were also added in the etchant and the E-corr did not shift obviously. Therefore, we proposed that copper dissolution proceeds through an 'inner-sphere' pathway in solution containing bridging ligands. The electron is transferred from the copper surface into the cupric species through the ligands, which greatly influences the copper dissolution rate. The order of effectiveness of these ligands is SCN- > I- > Br- > Cl- > F-, which is related to their polarizability.