Patent ID: 7137867

Claim:
A thickness control method for a double side polisher, comprising: providing a double side polisher comprising, a machine base, a lower polishing plate rotatably supported on the machine base and comprising a polishing pad disposed on an upper surface thereof, a sun gear comprising external teeth and rotatably supported on the machine base, an internal gear comprising internal teeth and rotatably supported on the machine base, an electro-conductive carrier comprising external teeth for engaging with the external teeth of the sun gear and the internal teeth of the internal gear and having holes for work pieces to be inserted therein, an upper polishing plate comprising a polishing pad disposed on a lower surface thereof and configured to apply a polishing pressure to the work pieces inserted in the holes, the upper polishing plate being rotatably supported on the machine base, a drive system for rotating the upper and lower polishing plates, the sun gear and the internal gear around the same axis, a slurry supplying unit for supplying a slurry to the work pieces, and an eddy current sensor mounted in a cavity of the upper polishing plate for measuring a distance from the sensor to an upper surface of the carrier; placing the work pieces in the holes of the carrier; supplying the slurry to the work pieces; starting polishing the work pieces using the upper and lower polishing plates; and stopping the polishing when the distance to the upper surface of the carrier measured by the sensor is decreased by a predetermined value corresponding to a target amount of material removal from the work pieces.