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:
Oct. 20, 1987
Filed:
Aug. 05, 1986
Applicant:
Inventors:
Masahide Okumura, Sagamihara, JP;
Takashi Matsuzaka, Kokubunji, JP;
Genya Matsuoka, Ome, JP;
Norio Saitou, Iruma, JP;
Assignee:
Hitachi, Ltd., Tokyo, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G21K / ; H01J / ;
U.S. Cl.
CPC ...
250398 ; 2504922 ; 2503 / ; 250397 ;
Abstract
Disclosed is an electron beam exposure apparatus which includes an objective lens focusing an electron beam, and a dynamic focus correction lens dynamically correcting the focusing by the objective lens. The apparatus comprises a control circuit which, in order to prevent a current variation induced in the objective lens by the dynamic focus correction lens, controls current supplied to the objective lens so as to cancel the current variation induced in the objective lens due to the coil current of the dynamic focus correction lens.