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. 26, 1995
Filed:
Jun. 14, 1994
James J Greed, Jr, Los Gatos, CA (US);
VLSI Standards, Inc., San Jose, CA (US);
Abstract
A test device for calibrating an optical surface inspection system, such as a pellicle or reticle inspection system, comprising a substrate having raised diffractors with at least one beam-diffracting geometric feature aligned to diffract light directed from an angle of incidence of less than 30.degree. . The beam-diffracting geometric feature is preferably a vertex aligned generally perpendicular to the surface of the substrate. A detection beam which impinges the vertex is diffracted, with diffracted beams being collected by a collector. The raised diffractor thereby simulates a foreign particle on a substrate, allowing calibration of the system. The apparent size of the diffractor and therefore the simulated particle can be varied by varying the vertices or the height of the raised diffractor. If a substrate is to have more than one diffractor, the diffractor should be spaced apart by a distance greater than the diameter of the detection beam.