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. 04, 2000
Filed:
Mar. 06, 1997
Jan E Van Der Werf, Eindhoven, NL;
Peter Dirksen, Eindhoven, NL;
U.S. Philips Corporation, New York, NY (US);
Abstract
A differential interferometer system for measuring the mutual positions and movements of a first object (WH) and a second object (MH). The system comprises a first interferometer unit (1, 2, 3, 4) having a first measuring reflector (RW) and a second interferometer unit (5, 6, 7, 8) having a second measuring reflector (RM). Since a measuring beam (b.sub.m) passes through both the first and the second interferometer unit and is reflected by both the first and the second measuring reflector, and since the measuring beam and the reference beam (b.sub.r) traverse the same path at least between the two interferometer units, accurate measurements can be preformed very rapidly. The interferometer system may be used to great advantage in a step-and-scan-lithographic projection apparatus.