This paper presents the integration of ultra-thin (similar to25Angstrom) ALD WNxCy as a Cu barrier in a dual damascene structure for both oxide and porous low-k dielectrics. Data on 200mm oxide wafers include complete electrical probe and reliability performance. Preliminary oxide electrical data are also presented on 300mm wafers, demonstrating the extendibility of the ALD technique. Lastly, we present data on the integration of ALD WNxCy on a porous low-k material including an attempt to seal the pores using a CVD SiCN dielectric liner on 200mm wafers.