To improve the wear resistance of Cu/Ni multilayer films, a Cu-Sn-Ni alloy boundary layer was formed between Cu/Ni layers through repeated electrochemical deposition of Cu, Sn, and Ni, and by annealing of the Cu/Sn/Ni/Sn multilayer film. The wear resistance of the annealed Cu/Sn/Ni/Sn film was higher than that of the Cu/Ni film, but the wear resistance of a single layer of Sn is much lower than those of Cu and Ni. The XRD and XPS measurements of the annealed Cu/Sn/Ni/Sn film indicated that the Cu-Sn-Ni alloy was Cu2
alloy, with Sn atoms distributed at the interface of Cu/Ni layers. Results suggest that an increase in adhesion of Cu and Ni layers with the boundary layers improved the wear resistance of multilayer films.