Interferometric measuring apparatus for measuring multiple layer structures using optimal selection of the input beam length

摘要

The apparatus has a scanning device formed such that when a reference beam path and an object beam path stay the same, the sample length is at least as large as the expected distance between two adjacent layer boundaries. When the interferometric part is imaged as a white light interferometer the coherence length of the input beam is at least large enough that the maxima of the correlograms can be distinguished. Independent claims also cover a method of interferometric measurement.