Optics: measuring and testing – Inspection of flaws or impurities – Having predetermined light transmission regions
Patent
1983-12-30
1987-04-07
Kittle, John E.
Optics: measuring and testing
Inspection of flaws or impurities
Having predetermined light transmission regions
219121LQ, 350620, 350622, 350625, 356338, 362297, 2502222, 250572, G01N 2147
Patent
active
046555927
ABSTRACT:
An apparatus and method are disclosed for detecting the presence of particles on the surface of a material, such as a semiconductor wafer, using the principle of scattered light. Light from a mercury arc lamp is collimated by a Cassegrain mirror collimator. The collimated beam of light is deflected by an annular shaped 45.degree. mirror toward a truncated annular shaped inverted parabolic mirror. Light striking the parabolic mirror is reflected outward in all directions as a converging beam of light toward a ring mirror. Light striking the ring mirror is reflected inward and strikes the surface from all directions at an angle of about 78.degree. to 86.degree. from normal incidence as a small spot. An objective lens located a distance directly above the area on the surface illuminated by the spot of light and mounted at one end of a light tight tube collects light scattered by any particles on the surface, but not light reflected by the surface, and forms an image of the light so collected on the light sensitive surface of a photodetector mounted at the other end of the tube. The wafer is mounted on a holder which is movable rotationally and translationally relative to the impinging light beam so that the entire surface of the wafer may be scanned by the light beam, an area at a time.
REFERENCES:
patent: 2097494 (1937-11-01), Lihotzky
patent: 2930287 (1960-03-01), Franks
patent: 3782836 (1974-01-01), Fey et al.
patent: 3930713 (1976-01-01), Stankewitz et al.
patent: 4127318 (1978-11-01), Determann et al.
patent: 4377340 (1983-03-01), Green et al.
patent: 4449818 (1984-05-01), Yamaguchi et al.
IBM Tech. Disclosure Bull., vol. 22, #4, p. 1360, Aug. 1979.
IBM T.D.B., vol. 2, #10, p. 1672, Mar. 1970.
IBM T.D.B., vol. 21, #6, p. 2336, Nov. 1978.
Hamamatsu Systems Inc.
Kittle John E.
Kriegsman Irving M.
LandOfFree
Particle detection method and apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Particle detection method and apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Particle detection method and apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1083032