Michael Scott Ferrara

US Patent:

56918127, Nov 25, 1997

Filed:

Mar 22, 1996

Appl. No.:

8/620890

Inventors:

Eugene C. Bates - Ft. Mill SC
Michael B. Ferrara - Charlotte NC

Assignee:

ADE Optical Systems Corporation - Charlotte NC

International Classification:

G01J 102

US Classification:

356243

Abstract:

The calibration standard has artificial defects of a predetermined uniform size disposed on selected areas of a substrate. The artificial defects are randomly spaced within the selected area and of a sufficient density as to be visually discernable through a CRT display or other output device. The selected areas in which the artificial defects are disposed are formed by positioning a mask above the substrate. The open areas of the mask correspond to the selected areas on which the artificial defects are disposed. The form of these open areas may correspond to a character representing the predetermined size of the artificial defect. If this is the case, the operator can determine the size of the artificial defects on a substrate without reference to any external source. The method of calibrating the defect inspection system includes positioning the calibration standard within the defect inspection system, measuring the size of the artificial defects detected by the inspection system, identifying the size of the artificial defects by viewing the indicia on the substrate, and comparing the size indicated by the indicia to the size actually measured by the defect inspection system.