Patent ID: 8475644

Claim:
An apparatus for electroplating metal onto a substrate, the apparatus comprising: (a) a plating chamber configured to contain an electrolyte and an anode while electroplating metal onto the substrate; (b) a substrate holder configured to hold the substrate such that a plating face of the substrate is positioned at a defined distance from the anode during electroplating, the substrate holder having one or more electrical power contacts positioned around a substantially circular perimeter and arranged to contact an edge of the substrate and provide electrical current to the substrate during electroplating; (c) an ionically resistive ionically permeable element shaped and positioned between the substrate and the anode during electroplating, the ionically resistive ionically permeable element having a substantially flat surface that is substantially parallel to and separated from a plating face of the substrate, wherein the ionically resistive ionically permeable element has an ionically resistive body with a plurality of perforations made in the body such that the perforations do not form communicating channels within the body and wherein said perforations allow for transport of ions through the element; (d) a variable field shaping element positioned between the ionically resistive ionically permeable element and the position of the anode for electroplating; and (e) a first auxiliary cathode located between the anode and the ionically resistive ionically permeable element, and peripherally oriented to shape the current distribution from the anode, while the first auxiliary cathode is supplied with current during electroplating; and (f) a second auxiliary cathode positioned to be located between the ionically resistive ionically permeable element and the substrate during electroplating, wherein the second auxiliary cathode is adapted to divert a portion of ionic current from an edge region of the substrate.