Patent ID: 6908374

Claim:
A chemical mechanical polishing (CMP) apparatus for polishing a surface of a workpiece and for detecting a CMP endpoint, comprising: an optically transparent polishing belt to polish the surface of the workpiece, the polishing belt being movable in one or more linear directions; a workpiece holder to support the workpiece, the workpiece holder configured to press the workpiece against the polishing belt; a support plate adapted to support the polishing belt as the workpiece is pressed against the polishing belt; and an optical detection system to detect the CMP endpoint, the optical detection system disposed below the polishing belt and comprising a light source and a detector, the light source sending outgoing signals through the polishing belt to the surface of the workpiece and the detector receiving incoming reflected signals from the surface of the workpiece through the polishing belt wherein the polishing belt is moved bi-directionally.