A semiconductor structure having a pore sealed portion of a dielectric layer is provided. Exposed pores of the dielectric material are sealed using an anisotropic plasma so that pores along the bottom of the opening are sealed, and pores along sidewalls of the opening remain relatively untreated by the plasma. Thereafter, one or more barrier layers may be formed and the opening may be filled with a conductive material. The barrier layers formed over the sealing layer exhibits a more continuous barrier layer. The pores may be partially or completely sealed by plasma bombardment or ion implantation using a gas selected from one of O.sub.2, an O.sub.2/N.sub.2 mixture, H.sub.2O, or combinations thereof.