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. 01, 1991
Filed:
Dec. 09, 1987
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
Electron beam apparatus for use in testing integrated circuits uses a magnetic electron objective lens having a first end adjacent the circuit under test and a second end remote from the circuit. The magnetic field of the lens increases steeply to a maximum near the first end and falls gradually towards the second end. Secondary electrons emitted from the circuit are accelerated strongly by an electrostatic field into the first end of the lens and are retarded abruptly to speeds of the same order as their emission speeds in the region of maximum magnetic field. Further gradual retardation of the electrons takes place so that the electrons approach the second end of the lens parallel to the axis of the lens at substantially their emission speeds. A filter grid located at the second end of the lens and a collector of electrons passing through the filter grid enable the emission speeds of the secondary electrons to be measured.