Abstract
Highly flatness is necessary for silicon wafers. An optimization method of polishing conditions of Double Sided Polishing (DSP) was proposed for the purpose. A wafer is held in a carrier of a DSP apparatus. The carrier moves in conjunction with the movement of a sun gear and an internal gear of the DSP apparatus. Polishing pads that contact with both sides of the wafer rotate independently with the wafer and gear movements. The wafer motion in the DSP apparatus was modeled in order to analyze the rotation speed and the relative velocity to the pads. The DSP conditions such as rotation speeds of the gears and the pads in the DSP apparatus were optimized in order to unify the friction distance distribution in the wafer. The Quasi-Newton method was used for the optimization. A penalty function was also used to take apparatus limitations into consideration as constraints in the optimization.
