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. 12, 1996
Filed:
Mar. 29, 1995
Toshiyuki Ishimaru, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
There is provided a dust particle inspection apparatus which comprises a laser beam source for emitting a laser beam having a coherence distance longer than 1 km; a scanner for scanning the surface of an article, which is to be inspected, with the emitted laser beam; an optical detector for detecting the laser beam reflected and diffracted on the surface of the article being inspected; a stage for setting the article thereon and displacing the same in a predetermined direction; and a gas supply means for surrounding the article with a high-purity inert gas atmosphere. There is also provided a dust particle inspection method which comprises the steps of surrounding the article under inspection with a high-impurity inert gas atmosphere; while displacing the article in a predetermined direction, scanning the surface of the article with a laser beam having a wavelength .lambda. and a coherence distance longer than 1 km; and detecting the laser beam reflected and diffracted on the surface of the article to thereby detect any dust particle or the like with high precision and certainty on the surface of the article such as a reticle.