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. 11, 2024
Filed:
Jan. 04, 2019
Asml Netherlands B.v., Veldhoven, NL;
Pieter Cristiaan De Groot, Heeze, NL;
Johannes Jacobus Matheus Baselmans, Oirschot, NL;
Derick Yun Chek Chong, 's Hertogenbosch, NL;
Yassin Chowdhury, Geldrop, NL;
ASML Netherlands B.V., Veldhoven, NL;
Abstract
A two-dimensional diffraction grating for a phase-stepping measurement system for determining an aberration map for a projection system comprises a substrate provided with a square array of through-apertures, wherein the diffraction grating is self-supporting. It will be appreciated that for a substrate provided with a square array of through-apertures to be self-supporting at least some substrate material is provided between each through-aperture and the adjacent through apertures. A method of designing a two-dimensional diffraction grating for a phase-stepping measurement system for determining an aberration map for a projection system comprises: selecting a general geometry for the two-dimensional diffraction grating, the general geometry having at least one parameter; and selecting values for the least one parameter that result in a grating efficiency map for the two-dimensional diffraction grating so as to control the contributions to a first harmonic of a phase stepping signal.