An electrochemical apparatus is provided which deposits material onto or removes material from the surface of a workpiece. The apparatus comprises a polishing pad and a platen which is in turn comprised of a first conductive layer in contact with the polishing pad and coupled to a first potential, a second conductive layer coupled to a second potential, and a first insulating layer disposed between the first and second conductive layers. At least one electrical contact is positioned within the polishing pad and is electrically coupled to the second conductive layer. A reservoir is provided which places an electrolyte solution in contact with the polishing pad and the workpiece. A carrier positions and/or presses the workpiece against the polishing pad.