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:
Jan. 07, 2003
Filed:
Dec. 19, 2000
Applicant:
Inventors:
Assignee:
Seiko Instruments Inc., , JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H01J 3/728 ;
U.S. Cl.
CPC ...
H01J 3/728 ;
Abstract
The invention is to observe semiconductor wafers with higher resolution at a low acceleration voltage—in particular, achieving such high-resolution observability when a wafer is inclined or tilted at large angles. A composite lens is used which consists essentially of a single-pole or monopole magnetic field type lens and an electrostatic field invasive lens whereas an electrode of the electrostatic field invasive lens which opposes the wafer is made of a magnetic material while letting a high voltage of the negative polarity be applied to this electrode and the wafer. Even when the wafer is tilted, any astigmatism and axis failure will hardly occur.