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:
Jun. 26, 2001
Filed:
Jun. 17, 1999
Yoshihisa Ooae, Tokyo, JP;
Takamasa Satoh, Tokyo, JP;
Akio Yamada, Tokyo, JP;
Hiroshi Yasuda, Tokyo, JP;
Advantest Corporation, Tokyo, JP;
Abstract
An electron gun, preferably a four-pole electron gun, used in an electron beam exposure apparatus is formed by: a cathode for emitting an electron beam when supplying a negative and high-accelerated voltage; a first grid provided downstream of the cathode for focusing a crossover image of the electron beam when supplying a voltage which becomes a reverse bias for the cathode, and the cathode and the first grid being arranged at a high voltage side of a high voltage insulator; an anode for collecting the electron beam which passes through the first grid, and being arranged at a low voltage side of the high voltage insulator; and a second grid provided at the high voltage side of the high voltage insulator and between the first grid and the anode, and having an aperture for limiting an amount of the electron beam passing therethrough. A voltage which becomes a forward bias for the cathode is supplied to the second grid, and the crossover image is focused at the aperture of the second grid.