Disclosed are a method and a system for processing a semiconductor structure of the type including a substrate, a dielectric layer, and a TaN--Ta liner on the dielectric layer. The method comprises the step of using XeF2 to remove at least a portion of the TaN--Ta liner completely to the dielectric layer. In the preferred embodiments, the present invention uses XeF2 selective gas phase etching as alternatives to Ta--TaN Chemical Mechanical Polishing (CMP) as a basic "liner removal process" and as a "selective cap plating base removal process." In this first use, XeF2 is used to remove the metal liner, TaN--Ta, after copper CMP. In the second use, the XeF2 etch is used to selectively remove a plating base (TaN--Ta) that was used to form a metal cap layer over the copper conductor.