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:
Jan. 15, 2008
Filed:
Aug. 25, 2005
Arie Jeffrey Den Boef, Waalre, NL;
Maarten Hoogerland, Auckland, NZ;
Boguslaw Gajdeczko, Princeton, NJ (US);
Arie Jeffrey Den Boef, Waalre, NL;
Maarten Hoogerland, Auckland, NZ;
Boguslaw Gajdeczko, Princeton, NJ (US);
ASML Netherlands B.V., Veldhoven, NL;
Abstract
An alignment system uses a self-referencing interferometer that produces two overlapping and relatively rotated images of an alignment marker. Detectors detect intensities in a pupil plane where Fourier transforms of the images are caused to interfere. The positional information is derived from the phase difference between diffraction orders of the two images which manifests as intensity variations in the interfered orders. Asymmetry can also be measured by measuring intensities at two positions either side of a diffraction order.