POLISHING END POINT DETECTION METHOD

摘要

A method for detecting an end point of a polishing operation (e.g., a polishing stop point or a changing point of polishing conditions) of a film of a substrate is described. The method includes applying light to a surface of a substrate during polishing of the substrate; receiving reflected light from the surface of the substrate, monitoring a first characteristic value and a second characteristic value calculated from reflection intensities at different wavelengths; detecting a point when an extremal point of the first characteristic value and an extremal point of the second characteristic value appear within a predetermined time difference; after detecting the point, detecting a predetermined extremal point of the first characteristic value or the second characteristic value; and determining a polishing end point based on a point when the predetermined extremal point is detected.