Patent ID: 7862693

Claim:
An electroplating apparatus for electroplating a surface of a wafer, the surface of the wafer capable of being electrically charged as a cathode, comprising: a plating head capable of being positioned either over or under the surface of a wafer and capable of being electrically charged as an anode, the plating head capable of enabling metallic plating between the surface of the wafer and the plating head when the wafer and plating head are charged, the plating head further including, a reservoir for holding an electrolytic solution and a plating chemistry; a porous applicator coupled to the reservoir at a location that is proximate to the surface of the wafer, the porous applicator defined to deliver the electrolytic solution and the plating chemistry for metallic plating the surface of the wafer; a first voltage sensor pair defined between the porous applicator at a first side of the plating head, the first voltage sensor defined to sense a voltage between the plating head and the surface of the wafer; a second voltage sensor pair defined between the porous applicator at a second side of the plating head, the second voltage sensor pair defined to sense the voltage between the plating head and the surface of the wafer; a pair of electrical contacts charged as a cathode defined to make contact with the surface of the wafer when the plating head is active, the electrical contacts being movable, and wherein one of the electrical contacts is defined to be placed apart from the surface of wafer when plating near the one of the pair of electrical contacts; and a controller processing data from the first and second voltage sensor pairs, the data being used by the controller to maintain a substantially constant voltage between the surface of the wafer and the plating head, and wherein the controller changes a voltage applied by the anode in response to sensing voltage changes from either the first voltage sensor pair or the second voltage sensor pair.