Patent ID: 6093082
Filing Date: 2000-07-25
Classification: B24B

Abstract:
An assembly for a chemical mechanical polishing system, comprising:a carrier head including a base, a flexible membrane extending beneath the base to define a chamber between an upper surface of the membrane and the base, a lower surface of the flexible membrane providing a substrate receiving surface, and an aperture in the flexible membrane between the substrate receiving surface and the chamber, the aperture configured such that if a fluid is evacuated from the chamber and a generally flat substrate is attached to the substrate receiving surface, the substrate blocks the aperture so that a pressure in the chamber drops to first pressure which is different from a second pressure that would result if the substrate were not attached to the substrate receiving surface;a vacuum source connected to the chamber to evacuate a fluid from the chamber;a sensor to measure a pressure in the chamber and generate an output signal representative thereof; anda processor, in response to the output signal, configured to indicate whether the substrate is attached to the substrate receiving surface.