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:
Nov. 10, 1998
Filed:
Feb. 06, 1997
Satoru Fukuhara, Hitachinaka, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An SE electron source in an apparatus utilizing an electron beam such as an electron microscope or electron beam lithography machine has an electron source structure particularly well suited for an electron gun in which the probe current is varied by the control voltage. The electron source includes a needle whose tip has a cone angle of less than 15 degrees and a radius of curvature of less than 0.5 .mu.m. In an electron gun using an SE electron source according to the invention, the range of variations in probe current caused by a given variation in control voltage is increased, permitting one extraction voltage setting to suffice and the value of the extraction voltage to decrease. Damage to the needle tip due to electric discharge is prevented adding to the stability of the electron gun.