US Patent 8736056 Device for reducing contact resistance of a metal

A structure for an integrated circuit with reduced contact resistance is disclosed. The structure includes a substrate, a cap layer deposited on the substrate, a dielectric layer deposited on the cap layer, and a trench embedded in the dielectric layer. The trench includes an atomic layer deposition (ALD) TaN or a chemical vapor deposition (CVD) TaN deposited on a side wall of the trench, a physical vapor deposition (PVD) Ta or a combination of the PVD Ta and a PVD TaN deposited on the ALD TaN or CVD TaN, and a Cu deposited on the PVD Ta or the combination of the PVD Ta and the PVD TaN deposited on the ALD TaN or the CVD TaN. The structure further includes a via integrated into the trench at bottom of the filled trench.