REVERSE INTERFEROMETRIC METHOD AND APPARATUS FOR MEASURING LAYER THICKNESS

摘要

A reverse interferometric method for the determination of the thickness of a layer of material employs a multi-wavelength light source which generates a light beam which comprises a time- variant series of different monochromatic wavelengths. The beam is reflected from the body of material being measured and is detected by a broad spectrum wavelength detector which produces a signal comprising a series of data points indicating the reflectivity of the sample as a function of the time- variant series of monochromatic wavelengths. A signal processor processes these data points to fit them to a model waveform, and the frequency of the model waveform is used to calculate the thickness of the body of material. Further disclosed are apparatus for carrying out the method and use of the method in a continuous process for the fabrication of thin film materials.