Patent ID: 6293846
Filing Date: 2001-09-25
Classification: B24B,H01L

Abstract:
A polishing apparatus for polishing a workpiece, said apparatus comprising:a turntable having a polishing surface;a top ring for holding a workpiece and pressing the workpiece against said polishing surface of said turntable;a workpiece dislodgment detector for detecting, during a polishing operation, the situation that the workpiece is dislodged from said top ring, said detector comprising a photoelectric gloss sensor for emitting light, receiving reflected light and detecting the workpiece that is dislodged from said top ring based on a change in a quantity of said reflected light, said sensor comprising a light-emitting diode for emitting light, a polarizing filter for allowing only S wave of the light from said light-emitting diode to pass therethrough, and a beam splitter for separating said reflected light into S wave and P wave, thus detecting the workpiece that is dislodged based on a difference in glossiness.