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:
Jun. 24, 2008
Filed:
Mar. 29, 2006
Maurits Van Der Schaar, Veldhoven, NL;
Arie Jeffrey Den Boef, Waalre, NL;
Everhardus Cornelis Mos, Best, NL;
Stefan Carolus Jacobus Antonius Keij, Breda, NL;
Maurits Van Der Schaar, Veldhoven, NL;
Arie Jeffrey Den Boef, Waalre, NL;
Everhardus Cornelis Mos, Best, NL;
Stefan Carolus Jacobus Antonius Keij, Breda, NL;
ASML Netherlands B.V., Veldhoven, NL;
Abstract
A lithographic apparatus arranged to transfer a pattern from a patterning device onto a substrate includes two reference gratings provided in the substrate and two measurement gratings on top of the reference gratings, the measurement gratings being similar to the reference gratings, and oppositely biased in a single direction relative to the respective reference gratings. An overlay measurement device with an image sensor is used for obtaining pixel data of a measurement spot in each of the two measurement gratings. Asymmetry for each pixel in the measurement spot is measured, and from the pixel asymmetry measurements in associated pixels of each of the two measurement gratings an overlay value and a process dependent value is determined, as well as a quality indicator for the overlay value and the process dependent value.