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:
Dec. 22, 2020
Filed:
Jul. 31, 2019
Corning Incorporated, Corning, NY (US);
Thomas James Dunn, Penfield, NY (US);
John Weston Frankovich, Fairport, NY (US);
Robert Dennis Grejda, Fairport, NY (US);
Christopher Alan Lee, Pittsford, NY (US);
Matthew Ronald Millecchia, Fairport, NY (US);
Yoshihiro Nakamura, Saitama, JP;
Corning Incorporated, Corning, NY (US);
Abstract
The methods disclosed herein include recording at near-vertical first and second measurement positions respective first and second interferograms of the photomask surface and defining a difference map as the difference between the first and second interferograms. Respective first and second normal forces on the photomask are also measured at the first and second measurement positions. The change in the normal force is used define a scaling factor, which is applied to the difference map to define a scaled difference map. A compensated flatness measurement with a reduced shape contribution due to gravity is obtained by subtracting the scaled difference map from the first interferogram. An interferometer-based flatness measurement system is also disclosed.