Embodiments of the invention generally provide methods and apparatuses for electroprocessing a substrate. In one embodiment, an apparatus for electrochemically processing the substrate includes a conductive processing surface adapted for processing a substrate thereon, and a polishing head for retaining the substrate against the processing surface. At least one drive mechanism provides relative motion between the conductive processing surface and the substrate. A first electrode is disposed below the conductive processing surface and is comprised of a first material. A second electrode is disposed radially inward of the first electrode and comprised of a second material.