Patent ID: 7507144

Claim:
A substrate polishing apparatus comprising: a polishing table; a polishing pad mounted on said polishing table for polishing a semiconductor substrate, said polishing pad having a through hole formed therein; a light emission and reception device having an emitter for emitting measurement light through said through hole formed in said polishing pad to the semiconductor substrate and a receiver for receiving reflected light from the semiconductor substrate so as to measure a film on the semiconductor substrate, said light emission and reception device being disposed in said polishing table; a supply passage for supplying a fluid to a path of the measurement light so as to produce a flow of the fluid from said light emission and reception device to the semiconductor substrate; and a discharge passage for discharging the fluid in the path of the measurement light, said discharge passage being provided in said polishing table and having a fluid connection with said supply passage, wherein said supply passage has an outlet portion, said outlet portion having a first end disposed within the supply passage and a second end that terminates within the through hole, and a portion of said emitter and a portion of said receiver are located within said outlet portion.