Patent ID: 6650408
Filing Date: 2003-11-18
Classification: B24B,G01N

Abstract:
A method for inspecting a polishing pad, comprising:obtaining reference data from a surface of a reference polishing pad which is known to produce a defect-free wafer; radiating a beam onto a region extending across a radial unit area of the polishing pad to be inspected while rotating the polishing pad such that the radial unit area scan a surface of the rotating polishing pad; obtaining empirical optical data of the radial unit area scanning the surface of the polishing pad to be inspected; comparing the reference data with the empirical data to determine whether a defect is present in the radial unit area scanning the surface of the polishing pad; and determining a position of a defect in the polishing pad by using both a position of the defect in the radial unit area and a rotational angle of the polishing pad from a reference point.