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. 11, 1991
Filed:
May. 30, 1990
Applicant:
Inventor:
Akira Yonezawa, Tokyo, JP;
Assignee:
Seiko Instruments, Inc., Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01J / ;
U.S. Cl.
CPC ...
2503 / ; 250310 ;
Abstract
An unipolar magnetic field type objective lens used as an objective lens of an electron beam device. By properly adjusting the shape and strength of the objective lens, not only the aberration coefficients of the objective lens are reduced but also the secondary electrons emitted from a sample are efficiently detected to thereby allow semiconductor wafers of large diameter to be observed at a low acceleration voltage, a large angle of inclination, and with a high resolution.