Implementations disclosed describe an optical inspection device comprising a source of light to direct a light beam to a location on a surface of a wafer, the wafer being transported from a processing chamber, wherein the light beam is to generate, a reflected light, an optical sensor to collect a first data representative of a direction of the first reflected light, collect a second data representative of a plurality of values characterizing intensity of the reflected light at a corresponding one of a plurality of wavelengths, and a processing device, in communication with the optical sensor, to determine, using the first data, a position of the surface of the wafer; retrieve calibration data, and determine, using the position of the surface of the wafer, the second data, and the calibration data, a characteristic representative of a quality of the wafer.