Apparatus and method for detecting defects and dust on a patterned surface
Patent 4598997 Issued on July 8, 1986. Estimated Expiration Date: 
July 8, 2003. 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.
July 8, 2003. 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 ReferencesDefect detection system Defect detection and plotting system Photoelectric detecting apparatus Defect detection system Method for determining the quality of light scattering material Method and apparatus for inspecting specimen surface Patent #: 4423331 InventorsAssigneeApplicationNo. 06/399290 filed on 07/19/1982US Classes:356/237.5, On patterned or topographical surface (e.g., wafer, mask, circuit board)250/559.41, With foreign particle discrimination circuitry250/559.45, With defect discrimination circuitry356/446With diffusionExaminersPrimary: Willis, Davis L.Assistant: Koren, Matthew W. Attorney, Agent or FirmInternational ClassesG01N 21/956 (20060101)G01N 21/88 (20060101) G01N 21/94 (20060101) Foreign Application Priority Data1982-02-15 GBAbstractApparatus for detecting defects and dust on patterned surfaces, such as patterned wafers, or grooved video disks, utilizes a scanning laser that provides light scattered by defects and dust. The scattered light is detected substantially free of diffracted beams from the pattern by a mask having apertures arranged to pass to the detector only scattered light and to block diffracted light and specular reflections. | |
