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US 4,441,124 AGranted
Technique for inspecting semiconductor wafers for particulate contamination
AssigneeWestern Electric Company, Inc.
InventorsRichard W. Heebner, Randal L. Schmitt
Life of this patent
Estimating the term…
Abstract
A laser beam (88) is raster scanned over the surface of a patterned semiconductor wafer (66) at an angle normal thereto. A plurality of detectors, radially spaced from the wafer (66) and substantially coplanar therewith detect light scattered from contaminating particulate thereon. The detected light is converted into a video signal that is forwarded to a video monitor (84) to display the particulate material while eliminating the patterned surface background.
Claims6
An apparatus for detecting particulate material on the surface of a semiconductor wafer having a pattern thereon, comprising:
- means for scanning a beam of light over the patterned surface of the wafer at an angle normal thereto;
- and
- a plurality of detectors mounted circumferential of the wafer and substantially coplanar with the surface thereof for detecting light scattered substantially along the surface of the wafer by the particulate material and not the pattern.
Dependencies are inferred from the claim text.