Patent ID: 8128458
Filing Date: 2012-03-06
Classification: B24B

Abstract:
1. A method for detecting escape of a substrate from a top ring, the method comprising: holding a substrate with a top ring; starting irradiating light by a light irradiation member when the top ring starts lowering or when a predetermined time has elapsed after the top ring has started lowering; starting taking a continuous image of an area irradiated with the light and detecting the escape of the substrate from the top ring by processing information on the continuous image when a predetermined time has elapsed after the starting of the irradiating of the light by the light irradiation member; performing polishing of the substrate by pressing the substrate held by the top ring against a polishing pad of a polishing table while moving the substrate and the polishing pad relative to each other; after completion of the polishing of the substrate, stopping the taking of the continuous image and the detecting of the escape of the substrate from the top ring when the top ring starts rising or when a predetermined time has elapsed after the top ring has started rising; and stopping the irradiating of the light by the light irradiating member when a predetermined time has elapsed after the stopping of the taking of the continuous image.