An apparatus (300) capable of assisting in controlling an electrolyte flow and an electric field distribution used for processing a substrate (10) is provided. It includes a rigid member (320) having a top surface of a predetermined shape and a bottom surface. The rigid member (320) contains a plurality of channels (324), each forming a passage from the top surface to the bottom surface, and each allowing the electrolyte and electric field flow therethrough. A pad (330) is attached to the rigid member via a fastener. The pad also allows for electrolyte and electric field flow therethrough to the substrate (10). |