Patent ID: 8012319

Claim:
An apparatus for electroplating a semiconductor substrate, the apparatus comprising: a first chamber having an inlet port that is adapted to provide a plating solution; a second chamber having a drain port that is adapted to drain the plating solution, wherein the first chamber is substantially adjacent to the first chamber; a shield that is located between the first and second chambers; a first electrode that is located in the first chamber; a second electrode that is located in the second chamber, wherein the semiconductor substrate is adapted to be electrically coupled to the second electrode and be separated from the shield by a distance; and a plurality of openings formed in the shield that allow for fluid communication between the first and second chambers, wherein the plurality of openings are arranged in a pattern area such that an electric field formed between the first electrode and the semiconductor substrate through the plating solution produces a substantially uniform current density across a target area of the semiconductor substrate at the distance, and wherein the pattern area is substantially oval having a major axis, a minor axis, and a center, and wherein the plurality of openings includes: a first opening formed along at least a portion of the major axis of the pattern area, wherein the first opening is elongated; a second opening formed along at least a portion of the minor axis of the pattern area, wherein the second opening is elongated, and wherein the first and second openings intersect at the center of the pattern area; a third opening that is substantially adjacent to the periphery of the pattern area along the minor axis of the pattern area, wherein the third opening is substantially circular; and a set of fourth openings arranged in a symmetrical pattern, wherein each fourth opening is substantially adjacent to the periphery of the pattern area, and wherein each fourth opening is substantially circular.