Method for detecting buried layers

US9500582B2 · kind B2 · utility

Assignee

• HSEB Dresden GmbH · DE

Inventors

• Bernd Srocka · Berlin, DE
• Ralf Langhans · Dresden, DE

Key dates

• Filing date: Sep 29, 2014
• Grant date: Nov 22, 2016
• Expiry date: Sep 29, 2034

Classification

• Technology area (CPC G): Physics
• CPC primary: G01N2201/068
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

An arrangement for optically detecting buried layers of flat objects having a plurality of layers, in particular wafers, containing a radiation source for illuminating the surface of the object at an angle; a polarization filter arranged in the beam path; and a detector for detecting radiation reflected by the surface of the object or transmitted by the object; is characterized in that that layer of the object which is closest to the radiation source at least partially transmits the radiation from the radiation source; the polarization filter transmits only radiation which is polarized parallel to the plane of incidence; and the surface of the object is illuminated at the Brewster angle. The surface of the object is preferably illuminated with unpolarized radiation and the polarization filter is arranged in the beam path between the surface of the object and the detector.