The methods and systems described provide for an in-situ endpoint detection for
material removal processes such as chemical mechanical processing (CMP) performed
on a workpiece. In a preferred embodiment, an optical detection system is used
to detect endpoint during the removal of planar conductive layers using CMP. An
optically transparent polishing belt provides endpoint detection through any spot
on the polishing belt. Once endpoint is detected, a signal can be used to terminate
or alter a CMP process that has been previously initiated.
