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. 19, 2001
Filed:
Sep. 29, 1999
Peter Dirksen, Eindhoven, NL;
Casparus A. H. Juffermans, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
Aberrations of an imaging system can be detected in an accurate and reliable way by imaging, by means of the imaging system, a circular phase structure on a photoresist, developing the resist and scanning it with a scanning detection device which is coupled to an image processor. The circular phase structure is imaged in a ring structure and each of several possible aberrations, like coma, astigmatism, three-point aberration, etc. causes a specific change in the shape of the inner contour and the outer contour of the ring and/or a change in the distance between these contours, so that the aberrations can be detected independently of each other. The new method may be used for measuring a projection system for a lithographic projection apparatus.