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. 11, 2003
Filed:
Dec. 20, 2001
Jan Martijn Krans, 5656 AA Eindhoven, NL;
Other;
Abstract
The invention relates to wafer inspection by means of a scanning electron microscope (SEM) column in which the secondary electron detector is positioned centrally above the objective lens of the column. Secondary electrons that leave the central part of the specimen in a direction substantially perpendicular to its surface are inevitably collected in the central part of the detector surface where the bore for the primary beam is situated. Consequently, such electrons do not contribute to the detector signal. In order to avoid such a detrimental loss of signal contribution, it is proposed to provide a central electrode in the central bore such that secondary electrons that approach the bore are driven aside towards the electron-sensitive detector region