a method for forming metallization in a workpiece includes electrochemically depositing a second metallization layer on the workpiece comprising a nonmetallic substrate having a dielectric layer disposed over a substrate and a continuous first metallization layer disposed on the dielectric layer and having at least one microfeature comprising a recessed structure , wherein the first metallization layer at least partially fills a feature on the workpiece , where the first metallization layer is a cobalt or nickel metal layer , and wherein the second metallization layer is a cobalt or nickel metal layer that is different from the metal of the first metallization layer , electrochemically depositing a copper cap layer after filling the feature , and annealing the workpiece to diffuse the metal of the second metallization layer into the metal of the first metallization layer .