Patent ID: 8568199

Claim:
An apparatus for detecting a polishing endpoint of a substrate including a film, the apparatus comprising: a light-applying unit configured to apply a light to a film-side surface of the substrate; a light-receiving unit configured to receive a reflected light from the substrate; a spectroscope configured to obtain a plurality of spectral profiles at predetermined time intervals, each spectral profile indicating reflection intensity at each wavelength of the reflected light; and a monitoring unit configured to monitor an amount of change in the reflection intensity obtained from the plurality of spectral profiles, wherein said monitoring unit is configured to select at least one pair of spectral profiles, including a latest spectral profile, from the plurality of spectral profiles obtained, calculate a difference in the reflection intensity at at least one predetermined wavelength between the spectral profiles selected, determine an amount of change in the reflection intensity from the difference, and determine a polishing endpoint based on the amount of change.