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:
Apr. 13, 2021
Filed:
Oct. 01, 2014
Kla-tencor Corporation, Milpitas, CA (US);
Andrew Hill, Berkeley, CA (US);
Gregory Brady, Campbell, CA (US);
KLA-Tencor Corporation, Milpitas, CA (US);
Abstract
Methods and systems for relaying an optical image using a cascade arrangement of tilted, concave mirrors are presented. An exemplary optical relay system includes a cascade arrangement of four mirrors each having concave, spherical surface figures. The first and third mirrors are configured to focus collimated wavefronts and the second and fourth mirrors re-collimate diverging wavefronts reflected from the first and third mirrors. Each mirror is tilted such that wavefronts located in the local field plane and local pupil plane of each mirror are physically separated. The magnitude and direction of each tilt angle are arranged such that off-axis aberrations introduced by each individual mirrors are largely compensated by the other mirrors. Such an optical relay system is employed to relay images of the pupil plane of a metrology system that is configured to perform accurate measurements of semiconductor structures and materials over a broad range of illumination wavelengths.