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:
Sep. 01, 1992
Filed:
Jan. 24, 1991
Applicant:
Inventors:
Stefan Wittekoek, all from Veldhoven, NL;
Marinus A Van Den Brink, all from Veldhoven, NL;
Theodorus A Fahner, all from Veldhoven, NL;
Assignee:
ASM Lithography B.V., Veldhoven, NL;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G03B / ;
U.S. Cl.
CPC ...
355 53 ;
Abstract
A projection apparatus is described having a reference plate with a set of grating marks in X and Y directions for aligning with an exposure mask having similar marks, and having four detectors for each mark, and having a lens system for projecting only the relevant mark on the relevant detector. A method of projecting is also described in which the detection signals are simultaneously processed with other signals to result in a control signal to adjust image quality.