Confocal microscope for layer thickness measurement and microscopy method for coating thickness measurement

摘要

A confocal microscope for layer thickness measurement comprises: optical elements for directing and focusing illumination light on a sample; a focus adjustment device, with which a relative displacement between a focus position of the illumination light and a sample position is made along an optical axis of the confocal microscope; a confocal light measuring device, with which measurement signals can be received at different settings of the focus adjustment device; an evaluation device for determining a layer thickness of the sample, for which purpose the evaluation device determines intensity band positions of at least two intensity bands from a measurement curve recorded by the light measurement device, which indicates a measured light intensity as a function of the focus position, and at a position difference between the intensity band positions Layer thickness closes. The evaluation device is set up to conclude the layer thickness with the aid of a mathematical model which describes for overlapping intensity bands a dependence of the intensity band positions of at least one light wavelength and the layer thickness taking into account interference of the illumination light at the layer.