Selective etching of CoFeNiCu/Cu multilayers was investigated with different solutions: HNO3/alcohol, FeCl3/HCl, K2Cr2O7/H2SO4 and dilutions of FeCl3/HCl, K2Cr2O7/H2SO4. Polarization curves on a rotating disk electrode were used to assess the corrosion potential and current density of Cu, and Co-rich alloys. Preferential etching of the Co-rich alloy was attributed to either a less positive corrosion potential or a higher corrosion current density compared to the Cu layer. A dilution of the aqueous K2Cr2O7/H2SO4 solution was considered most promising for submicron structure development.