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. 12, 2022
Filed:
May. 03, 2021
Asml Netherlands B.v., Veldhoven, NL;
Zili Zhou, Eindhoven, NL;
Nitesh Pandey, Eindhoven, NL;
Olger Victor Zwier, Eindhoven, NL;
Patrick Warnaar, Tilburg, NL;
Maurits Van Der Schaar, Eindhoven, NL;
Elliott Gerard McNamara, Eindhoven, NL;
Arie Jeffrey Den Boef, Waalre, NL;
Paul Christiaan Hinnen, Veldhoven, NL;
Murat Bozkurt, Uden, NL;
Joost Jeroen Ottens, Veldhoven, NL;
Kaustuve Bhattacharyya, Veldhoven, NL;
Michael Kubis, Meerbusch, DE;
ASML Netherlands B.V., Veldhoven, NL;
Abstract
A method of measuring overlay uses a plurality of asymmetry measurements from locations (LOI) on a pair of sub-targets () formed on a substrate (W). For each sub-target, the plurality of asymmetry measurements are fitted to at least one expected relationship () between asymmetry and overlay, based on a known bias variation deigned into the sub-targets. Continuous bias variation in one example is provided by varying the pitch of top and bottom gratings (P/P). Bias variations between the sub-targets of the pair are equal and opposite (P/P). Overlay (OV) is calculated based on a relative shift (xs) between the fitted relationships for the two sub-targets. The step of fitting asymmetry measurements to at least one expected relationship includes wholly or partially discounting measurements () that deviate from the expected relationship and/or fall outside a particular segment of the fitted relationship.