Patent ID: 6077147
Filing Date: 2000-06-20
Classification: B24B

Abstract:
A chemical-mechanical polishing station for polishing a wafer in damascene process, comprising:a slurry supplier for delivering slurry;a polishing pad for collecting the slurry;a polishing head for holding and rotating the wafer as well as lowering the wafer down so that contact is made with the slurry and the polishing pad during a polishing session, the polishing head further including a retaining ring for positioning the wafer;a light-emitting device installed inside the retaining ring such that the light-emitting device is able to send out a beam of light onto the slurry;a light sensor installed inside the retaining ring such that the light sensor is able to receive the beam of light reflected back from the slurry; anda spectrum analyzer coupled to the light sensor for analyzing any color change in the slurry.