Abstract: A method for forming a self-aligned capping layer over a metal filled feature in a multi-layer semiconductor device including providing an anisotropically etched feature included in a substrate; blanket depositing a first barrier layer over the anisotropically etched feature to prevent diffusion of a metal species into the substrate; filling the anisotropically etched feature with a metal to form a metal filled feature substantially filled with metal; planarizing the substrate surface to include forming an exposed surface of the metal filled feature; and, selectively depositing a second barrier layer to cover the exposed surface of the metal filled feature to form a capping layer.