A process and reactor for electrochemical processing of at least one surface of a microelectronic workpiece is set forth. The reactor comprises a reactor head including a workpiece support that has one or more electrical contacts positioned to make electrical contact with the microelectronic workpiece. The reactor also includes a processing container (37) having a plurality of anodes (1095) disposed at different elevation in the principal fluid flow chamber so as to place them at different distances from a microelectronic workpiece under the process. One or more of the plurality of anodes may be in close proximity to the workpiece during the process. Still further, one or more of the plurality of anodes may be a virtual anode.