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:
Feb. 18, 2020
Filed:
Jun. 13, 2018
Asml Netherlands B.v., Veldhoven, NL;
Gonzalo Roberto Sanguinetti, Eindhoven, NL;
Murat Bozkurt, Uden, NL;
Maurits Van Der Schaar, Eindhoven, NL;
Arie Jeffrey Den Boef, Waalre, NL;
ASML Netherlands B.V., Veldhoven, NL;
Abstract
Overlay error of a lithographic process is measured using a plurality of target structures, each target structure having a known overlay bias. A detection system captures a plurality of images () representing selected portions of radiation diffracted by the target structures under a plurality of different capture conditions (λ). Pixel values of the captured images are combined () to obtain one or more synthesized images (). A plurality of synthesized diffraction signals are extracted () from the synthesized image or images, and used to calculate a measurement of overlay. The computational burden is reduced compared with extracting diffraction signals from the captured images individually. The captured images may be dark-field images or pupil images, obtained using a scatterometer.