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. 17, 1985
Filed:
Jan. 06, 1983
Nobuyuki Akiyama, Yokohama, JP;
Mitsuyoshi Koizumi, Yokohama, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An apparatus for detecting contaminants depositing on the reticle of a reduction projection mask aligner comprises a laser spot projector which conducts a laser beam to the light path upstream of the condenser lens of the aligner such that the laser beam is in the same direction as of the exposure light beam. The laser spot projector projects the laser beam from above the reticle through the condenser lens so as to form a laser spot on the upper surface of the reticle. A laser spot scanner which scans the entire area of the reticle by the laser spot projected on to the reticle by the laser spot projector, and a photoelectric detector which receives the scattered light emitted aslant on the reticle surface, whereby a contaminant on the reticle is detected in accordance with the signal produced by the detector.