Inspecting apparatus for determining presence and location of foreign particles on reticles or pellicles
Patent 4966457 Issued on October 30, 1990. Estimated Expiration Date: 
January 19, 2009. 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.
January 19, 2009. 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 ReferencesMultiple source laser scanning inspection system Foreign substance inspecting apparatus Foreign substance inspecting apparatus Foreign particle detecting method and apparatus Patent #: 4669875 InventorsAssigneeApplicationNo. 298920 filed on 01/19/1989US Classes:356/239.7, Surface condition250/559.41, With foreign particle discrimination circuitry356/239.8, Detection of an object or particle on surface356/338With photocell detectionExaminersPrimary: McGraw, Vincent P.Assistant: Tuanga, S. A. Attorney, Agent or FirmInternational ClassG01N 021/88Foreign Application Priority Data1988-01-21 JPAbstractA defect inspecting apparatus for determining the presence of a defect element adhering to either of the front and back surfaces of a thin film-like object to be inspected (the object having a light-transmitting property) applies two light beams of different wavelengths to a surface of the object and varies the incident angle of the light beams. A first photoelectric detector receives light of the two light beams reflected by or transmitted by the object, and a second photoelectric detector receives light of the two light beams scattered by the defect element. A discriminator determines the surface of the object to which the defect element adheres based on detection outputs of the photoelectric detectors. | |
