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:
Aug. 04, 1987
Filed:
Sep. 20, 1985
Mamoru Nakasuji, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
In a method of adjusting on optical column in an electron beam exposure system, a pair of edges of a beam spot formed on a target by an electron beam is detected by rotating a first aperture mask which is located along an optical axis of an optical column. First and second blanking voltages applied to the first and second blanking deflector are adjusted so as not to completely blank the electron beam, but to minimize the detectable intensity of the beam spot. Firstly, the ration of the first voltage to the second voltage is gradually changed to shift the one pair of beam edges in a predetermined direction. The voltage ration of the voltages to be applied to the blanking deflector is determined by detecting the start of reverse shifting of the beam edges. Secondly, an excitation current supplied to a lens which projects an image of a first aperture onto a second aperture is increased to shift the other edge of the beam spot. The excitation current to be supplied to the lens is, similarly, determined by detecting the start of reverse shifting of the beam edges.