The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Nov. 30, 2004

Filed:

Feb. 07, 2003
Applicant:
Inventors:

Hakon Mikkelsen, Göttingen, DE;

Horst Engel, Giessen, DE;

Joachim Wienecke, Jena, DE;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G06F 1/500 ; G01B 1/102 ;
U.S. Cl.
CPC ...
G06F 1/500 ; G01B 1/102 ;
Abstract

A method and apparatus for determination of layer thicknesses and optical parameters of a number of layers of a specimen, in which the reflectance spectrum of the specimen is measured and then smoothed, and a modeled reflectance spectrum is adapted to the measured one by means of an optimization criterion so as thereby to determine the layer thickness. The optimization criterion is determined by the totality of the absolute values of the wavelength differences of all pairs of wavelengths, a pair of wavelengths being constituted by those wavelengths that respectively correspond to a selected extreme in the measured reflectance spectrum characterized by an index counting the extremes in ascending or descending order, and a selected extreme in the modeled reflectance spectrum having the same index.


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