Apparatus for the contact-less, interferometric determination of surface height profiles and depth scattering profiles

Abstract

An apparatus for the contact-less, interferometric investigation of a sample object (2), particularly for the determination of sample surface profiles and depth profiles of light scattering properties of the sample (2), comprises a light source (1), able to provide broadband, low-coherence light; a beam splitter (4), arranged to split up a source light beam (11) produced by the light source (1) into a reference light beam (31) and an object light beam (21), and arranged to recombine a reflected reference light beam (31′) and a reflected object light beam (21′) to a detection light beam (51); a reference mirror element (3), arranged to reflect said reference light beam (31) back to the beam splitter (4); and a one- or two-dimensional photo sensor (5), able to convert incident light of said detection light beam (51) to an electric current signal. The reference mirror element (3) is arranged to laterally and/or angularly displace the reflected reference light beam (31′) in relation to the optical axis (33) of the incident reference light beam (31). Interference between the reference light beam (31′) and the object light beam (21′) leads to fringe packets on the photo sensor, with a lateral shift that is a direct measure of the distance of a reflecting surface or scattering layer on the sample object to the beam splitter (4).

Dependencies are inferred from the claim text.