Foreign particle detecting method and apparatus
Patent 4669875 Issued on June 2, 1987. Estimated Expiration Date: 
June 2, 2004. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
June 2, 2004. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 2947212 3667846 3748047 Method of inspecting the surface of an object and apparatus therefor Foreign substance inspecting apparatus Patent #: 4468120 InventorsAssigneeApplicationNo. 06/548516 filed on 11/03/1983US Classes:356/237.3, Detection of object or particle on surface250/225, Polarizing250/559.09, With polarization250/559.41With foreign particle discrimination circuitryExaminersPrimary: Kittle, John E.Assistant: Dees, Jose G. Attorney, Agent or FirmInternational ClassesG01N 21/88 (20060101)G01N 21/94 (20060101) G01N 15/02 (20060101) Foreign Application Priority Data1982-11-04 JPAbstractThe foreign particle detecting method and apparatus are disclosed wherein a polarized laser beam emitted by a laser beam irradiating system from a direction inclined with respect to the direction perpendicular to the surface of a substrate is used by a scanning means to linearly scan the substrate surface from a direction approximately 90° with respect to the laser light irradiating direction; and the laser light reflected from a foreign particle on the substrate surface is detected by a polarized light analyzer and a photoelectric conversion device from a direction set approximately equal to said scanning direction and inclined with respect to the direction perpendicular to the substrate surface. | |
