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.
Patent No.:
Date of Patent:
Jul. 28, 2015
Filed:
Feb. 14, 2011
Wolfgang Sulik, Asslar, DE;
Lambert Danner, Vienna, AU;
Alexander Buettner, Weilburg, DE;
KLA-Tencor MIE GmbH, Weilburg, DE;
Abstract
A method for focusing an object plane () through an objective () and an optical assembly (), with which the method can be carried out, are disclosed. A geometric reference structure () is positioned in a plane () conjugate to a field plane () of the objective () and is imaged onto the object plane (). The geometric reference structure () is illuminated with a light beam (), which encloses a non-zero angle (φ) with a normal direction () of the conjugate plane (). Therefore a position (Y) of an image () of the geometric reference structure () in the object plane () depends on the signed distance () between the object plane () and the field plane (), and correspondingly is evaluated for the determination of the focus position. The optical assembly () preferentially may be a metrology tool () for measuring structures () on masks (), wherein the objective () is the measurement objective of the metrology tool ().