Patent ID: 9669515
Date: 2017-06-06
CPC Classifications: B24B,H01L

Claim:
1. A polishing apparatus for polishing a substrate, comprising: a polishing table configured to support a polishing pad; a carrier configured to hold the substrate and press the substrate against the polishing pad; a dam configured to dam a liquid on the polishing pad to form a liquid film having a thickness equal to or greater than a prescribed value, the dam being provided only in part of an area on the polishing pad and formed into an arcuately curved shape to allow the liquid on the polishing pad to flow into the dam and to allow the liquid in the dam to be discharged to the outside of the dam; a light emitter configured to emit a laser beam onto the polishing pad, the light emitter having a light emission end disposed in the liquid film formed by the dam; a light receiver configured to receive light scattered by and bounced off the polishing pad at a plurality of angles due to surface properties of the polishing pad, after the laser beam is emitted from the light emitter, the light receiver being disposed in the liquid film formed by the dam; and a processor configured to perform Fourier transform on the light received by the light receiver into a predetermined wavelength corresponding to a reflection intensity distribution and to determine a feature quantity of the surface properties of the pad.