Verfahren zur Messung der Schichtdicke und des Brechungsindex einer duennen Schicht auf einem Substrat und Vorrichtung zur Durchfuehrung des Verfahrens

The description refers to a process for the in-situ measurement of the thickness and refractive index of a thin layer on a substrate by means of the interference effects in the layer. Known interference methods permit a spatial resolution of the measured values in the layer plane. Instead of an external light source, the process according to the invention uses the temperature radiation of the substrate as a source of interfering partial beams. The intensity of the interfering partial beams is measured by means of a CCD camera from the measured signal of which the required parameters are calculated by means of a signal-processing electronic circuit based on the Airy function. The low time constant of the measurement and evaluation permit the use of the process for recording measured values for controlling coating and removal processes.