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:
Mar. 17, 2015
Filed:
Oct. 18, 2010
Henricus Johannes Lambertus Megens, Waalre, NL;
Johannes Anna Quaedackers, Veldhoven, NL;
Christian Marinus Leewis, Maastricht, NL;
Peter Clement Paul Vanoppen, Hechtel-Eksel, BE;
Henricus Johannes Lambertus Megens, Waalre, NL;
Johannes Anna Quaedackers, Veldhoven, NL;
Christian Marinus Leewis, Maastricht, NL;
Peter Clement Paul Vanoppen, Hechtel-Eksel, BE;
ASML Netherlands B.V., Veldhoven, NL;
Abstract
A method of measurement of at-resolution overlay offset may be implemented in a scatterometer. At least three targets are provided on a wafer, each target comprising a first marker grating and a second interleaved marker grating and each target having a different overlay bias between its first and second marker. The first and second markers are provided by subsequent lithography steps in a double patterning lithographic process. The targets are measured with a scatterometer and for each target a measured CD of at least one of the markers is determined using reconstruction. The CD of the first marker may be fixed in the reconstruction. The measured CDs and at least one of the overlay biases is used to determine an overlay result corresponding to a minimum measured CD. The overlay result may be determined by fitting a function such as a parabola to the measured CDs and the overlay biases and determining the overlay at the minimum of the fitted function.