Method and apparatus for detecting defective semiconductor wafers during fabrication thereof

An apparatus and method for detecting burnt resist or mask on the surface of a semiconductor integrated circuit wafer during fabrication thereof. A light source and light sensor are utilized to identify the flat matte surface finish of burnt resist or mask and shut down the fabrication process before a large number of semiconductor wafers are ruined. The burnt resist or mask is detected by the lack of reflected light from the surface of the wafer compared with the light reflected from the surface of a known good resist coated wafer.