A method of fabricating a semiconductor device including a metal interconnect structure with a conductive region formed in a first dielectric layer, and an overlying, low-k, dielectric layer. A via and trench are formed in a dual damascene structure in the overlying dielectric layer, the via aligned with the conductive region and the trench. A sacrificial liner to release organic residues is deposited in the via and over the upper surface of the wafer, over which an organic planarization layer is deposited. The organic planarization layer is removed with a dry plasma etch, followed by a wet clean to remove the sacrificial liner. A diffusion barrier to separate the conductive material from the dielectric layers is deposited over the dual damascene structure and over the upper surface of the wafer. A conductive structure is formed over the diffusion barrier and polished to form an even surface for further processing steps.