An optical surface analysis system for scanning the surface of a (silicon) wafer and detect if any residual material is still on the wafer surface in order to determine an appropriate end-point in a polishing process. An Optical Surface Analyzer (OSA), of the present invention, is generally used to identify composition, measure surface area, and measure thickness variations of thin film layers of material. The difference in optical properties (index of refraction) of different materials on the surface allows the system of the present invention to separate different materials on the wafer surface using the histogram plots generated by the OSA. This method is used to detect and make a quantitative assessment regarding the amount of residual material to be removed by the polishing process and, therefore, when an appropriate end-point has been reached in the polishing process.