Patent ID: 7394551
Filing Date: 2008-07-01
Classification: G01J,G01N

Abstract:
1. A reflection measurement apparatus which operates below deep ultra-violet (DUV) wavelengths, the apparatus comprising: a light source, the light source providing a source beam including wavelengths at or below DUV wavelengths; a sample channel light path; a reference channel light path; a spectrometer that receives light from the sample channel light path after the light has been reflected from a sample; and a detector that receives wavelengths of light at or below DUV wavelengths transmitted from an output of the spectrometer, wherein the reference channel light path is utilized for referencing the reflectometer so that at least some reflectometer system characteristics may be obtained proximate in time to obtaining reflectivity data from the sample, and wherein the sample channel light path and the reference channel light path are established using two or more controllable beam stops in the form of motorized fully reflecting mirrors to direct the entirety of the source beam through either the sample channel light or the reference channel light path and to direct the reference channel light path and the sample channel light path to a common diffraction element and a common detector.