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:
May. 12, 2020
Filed:
May. 15, 2018
Asml Netherlands B.v., Veldhoven, NL;
Stefan Michiel Witte, Hoofddorp, NL;
Gijsbert Simon Matthijs Jansen, Amsterdam, NL;
Lars Christian Freisem, Amsterdam, NL;
Kjeld Sijbrand Eduard Eikema, Hoofddorp, NL;
Simon Gijsbert Josephus Mathijssen, Rosmalen, NL;
ASML Netherlands B.V., Veldhoven, NL;
Abstract
A metrology apparatus () includes a higher harmonic generation (HHG) radiation source for generating () EUV radiation. Operation of the HHG source is monitored using a wavefront sensor () which comprises an aperture array () and an image sensor (). A grating () disperses the radiation passing through each aperture so that the image detector captures positions and intensities of higher diffraction orders for different spectral components and different locations across the beam. In this way, the wavefront sensor can be arranged to measure a wavefront tilt for multiple harmonics at each location in said array. In one embodiment, the apertures are divided into two subsets (A) and (B), the gratings () of each subset having a different direction of dispersion. The spectrally resolved wavefront information () is used in feedback control () to stabilize operation of the HGG source, and/or to improve accuracy of metrology results.