Co-P and Co-W-P alloy films were deposited by the electroless plating method on Cu foil or on Cu deposited by sputtering on a Ta/SiO2/Si/substrate. Dicarboxylic acids, used as buffering additives, increase the deposition rate and P quantity in the films. The cobalt deposition rate and P quantity in the films decrease with incorporation of tungsten into the films. AFM, XRD and XPS data indicate the differences between the structure of Co-P and Co-W-P films and confirm that Co-W-P films deposited from glycine containing solutions can serve as a perfect diffusion barrier layer to prevent Cu diffusion. (C) 2009 Elsevier B.V. All rights reserved.