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System and method of optically inspecting surface structures on an object

  • US 6,292,260 B1
  • Filed: 06/23/1999
  • Issued: 09/18/2001
  • Est. Priority Date: 07/03/1997
  • Status: Expired due to Term
First Claim
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1. A system for inspecting a surface of a semiconductor wafer having a straight side (flat), said system comprising:

  • a support for supporting the wafer to be inspected;

    a first energy-emitting device mounted at a height above the support approximately equal to the height of the surface of the wafer to be inspected and directed to emit energy along and substantially parallel to the surface of the wafer, wherein said first energy-emitting device is positioned at an azimuth angle of substantially 45°

    relative to the flat;

    a second energy-emitting device mounted at a height above the support approximately equal to the height of the surface of the wafer to be inspected and directed to emit energy along and substantially parallel to the surface of the wafer, and in a direction substantially opposing that of said first energy-emitting device;

    a third energy-emitting device mounted at a height above the surface of the wafer for emitting energy directed toward and substantially perpendicular to the wafer surface to be inspected; and

    an image-capturing device aimed to capture an image of the surface as illuminated by the first, second, and third energy-emitting devices.

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