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:
Aug. 10, 2004
Filed:
May. 26, 2000
Joseph J. Danko, Shrewsbury, MA (US);
Inspex Incorporated, Billerica, MA (US);
Abstract
A method and apparatus for inspecting a surface of a semiconductor wafer having repetitive patterns for contaminant particles using scattered light which involves directing two beams of light at different approach angles onto the surface in a manner so as to illuminate two intersecting stripe shaped regions on the surface. An imaging lens collects scattered light from the surface as the semiconductor wafer is moving and then images the scattered light collected onto a CCD camera having a square array sensor and arranged to operate in a time delayed integration (TDI) mode. The field of view of the CCD camera is centered at the intersection of the two striped regions. Each light beam striking the surface produces a Fourier diffraction pattern of scattered light in the back focal plane of the imaging lens. In setting up the apparatus, the angle of incidence of one of the light beams is adjusted to shift one of the diffraction patterns, if necessary, so that it overlaps the other diffraction pattern. If the two approach angles are symmetrically disposed, then the two diffraction patterns overlap and adjustment of the angle of incidence of one of the beams is not necessary.