Abstract: A method and device for measuring the layer thickness of an object. Initially, an object with a layer thickness is provided. Thereupon, at least two measurement steps are performed, where electromagnetic radiation with frequencies in a frequency band associated with the respective measurement step is radiated on the object in each case. The frequency bands are different portions of one bandwidth. Secondary radiation emanating from the boundary surfaces of the object is detected and a measurement signal associated with the measurement step is ascertained. The measurement signals are combined according to the respective frequency bands associated with the measurement steps in order to form an evaluation signal; a fundamental frequency is determined therefrom, and the layer thickness is calculated. A large bandwidth can be realized by a narrow-bandwidth measurement steps by the method. As a result, physical limits of known methods are overcome, and the measurement accuracy is increased.

Abstract: A method and device for measuring the layer thickness of an object. Initially, an object with a layer thickness is provided. Thereupon, at least two measurement steps are performed, where electromagnetic radiation with frequencies in a frequency band associated with the respective measurement step is radiated on the object in each case. The frequency bands are different portions of one bandwidth. Secondary radiation emanating from the boundary surfaces of the object is detected and a measurement signal associated with the measurement step is ascertained. The measurement signals are combined according to the respective frequency bands associated with the measurement steps in order to form an evaluation signal; a fundamental frequency is determined therefrom, and the layer thickness is calculated. A large bandwidth can be realized by a narrow-bandwidth measurement steps by the method. As a result, physical limits of known methods are overcome, and the measurement accuracy is increased.