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.