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. 02, 1997
Filed:
May. 24, 1995
Applicant:
Inventors:
Joseph Pennell Kirk, Dutchess County, NY (US);
Ronald Michael Martino, Fairfield County, CT (US);
Assignee:
International Business Machines Corporation, Armonk, NY (US);
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G03B / ; G03B / ; G03B / ;
U.S. Cl.
CPC ...
355 71 ; 355 52 ; 355 55 ;
Abstract
Uniform illumination of a photomask in optical lithography is achieved with annular illumination of the conjugate pupil plane in a lithography tool. A spinning diffraction filter is placed in a stepper so as to provide annular illumination on a time averaged basis. This approach provides annular illumination for resolution enhancement in an easily manufacturable and flexible way and without significant loss of light intensity. No illuminator redesign in the photolithographic exposure tool is required.