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:
Aug. 31, 1999
Filed:
Nov. 27, 1996
Samson Kh Mil'shtein, Chelmsford, MA (US);
Joel M Therrien, Grafton, MA (US);
University of Massachusetts, Boston, MA (US);
Abstract
A method for testing a semiconductor device wherein an image produced from secondary electron emissions generated by exposing a cross section of the device to a beam of electrons with such device being in a first biased condition, preferably an unbiased condition, is digitally recorded in a memory of a digital computer. An image is produced from secondary electron emissions generated by exposing a cross section of the device to a scanning beam of electrons with such device being in a second biased condition is digitally recorded in the memory of the digital computer. The recorded images are digitally subtracted one from the other in the digital computer to produce a difference image. The digital computer digitally calculates a quantitative measure of voltage distribution across the exposed cross section from two regions in the difference image having different degrees of secondary electron emissions. The digital computer displays one of the digitally recorded images on a video display. The other one of the digitally recorded images is subsequently displayed on the video display and the identifiable regions of the two displayed images are identifiable on both displayed images.