An integrated circuit device has a substrate including a dielectric layer patterned with a pattern which includes a set of features in the dielectric for a set of metal conductor structures. An adhesion promoting layer is disposed on the set of features in the patterned dielectric. A ruthenium layer is disposed on the adhesion promoting layer. A cobalt layer is disposed on the ruthenium layer filling a first portion of the set of features. The cobalt layer has a u-shaped cross section having a thicker bottom layer than side layers. The cobalt layer is formed using a physical vapor deposition process. A metal layer is disposed on the cobalt layer filling a second, remainder portion of the set of features.