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:
Jul. 02, 2002
Filed:
Jun. 01, 1999
Michael S. Gordon, Lincolndale, NY (US);
Rodney A. Kendall, Ridgefield, CT (US);
David J. Pinckney, Danbury, CT (US);
Nikon Corporation, Tokyo, JP;
Abstract
A beam-limiting aperture truncates selected portions of a charged particle beam illuminating portions such as subfields of a patterned reticle of a charged particle beam projection lithography tool and then projects a pattern of charged particles onto a target in a charged particle beam lithography tool. The respective portions of the reticle are patterned in accordance with respective portions of an integrated circuit or other desired pattern and may have differing transmissivities; altering beam current at the target even when source beam current remains substantially constant. The portion of the beam which is truncated, thus altering the particle trajectory semi-angle and numerical aperture of the tool is controlled in accordance with the transmissivity of the reticle portion to enhance resolution to near optimal limits.