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:
Sep. 05, 2000
Filed:
Oct. 06, 1999
NEC Corporation, Tokyo, JP;
Abstract
Particles generated within a semiconductor wafer process chamber are monitored by emitting a rastered laser beam into the process chamber and detecting a two-dimensional image of scattered radiant energy within the process chamber. A video frame representing a matrix array of pixel intensities is produced and processed by a processor. The processor receives first and second video frames, the first frame representing a matrix array of pixels of a background image of the process chamber before a wafer processing is started and the second frame representing a matrix array of corresponding pixels of a target image of the process changer after a wafer processing is started. Differential intensities between the pixels of the background image and corresponding pixels of the target image are detected and a decision is made on the detected intensities to produce an output signal representing presence or absence of the particles.