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:
Mar. 21, 2000
Filed:
Aug. 27, 1998
Takeo Nozaki, Tokyo, JP;
Satoshi Nishii, Kanagawa, JP;
NEC Corporation, Tokyo, JP;
Abstract
A reference image forming method is used in a pattern inspection apparatus for scanning a pattern formed on an object to be inspected on the basis of design data with a laser beam having a predetermined wavelength, focusing transmitted light passing through the object on a light-receiving element by using an objective lens, forming a real image from pattern information obtained from the light-receiving element, and comparing the real image with a reference image obtained by imaging the design data, thereby detecting a defect in the object. In this method, reference data is formed by developing the design data as a pattern made of multilevel gradation values on pixels having a resolution higher than an inspection resolution. A reference image is formed by increasing or decreasing the width of each pattern of the reference data as a multilevel gradation pattern with a precision higher than the inspection resolution on the basis of an edge position of a corresponding pattern in the real image. A pattern inspection apparatus is also disclosed.