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Apparatus and method for testing defects

  • US 7,443,496 B2
  • Filed: 03/05/2007
  • Issued: 10/28/2008
  • Est. Priority Date: 04/02/1991
  • Status: Expired due to Fees
First Claim
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1. A defect inspection apparatus comprising:

  • an illumination optical unit for obliquely illuminating an object with a slit-like shaped laser, the slit-like shaped laser being converged in one direction and collimated in a direction transverse to the one direction;

    a first detection optical unit including a first image sensor for detecting a first image formed by light reflected from the object by the illumination of the slit-like shaped laser and reflected in a first direction substantially normal to a surface of the object;

    a second detection optical unit including a second image sensor for detecting a second image formed by light reflected from the object by the illumination of the slit-like shaped laser and reflected in a second direction inclined to the normal direction to the surface of the object;

    an image signal processing unit which processes both of a signal outputted from the first detection optical unit by the detection of the first image and a signal outputted from the second detection optical unit by the detection of the second image; and

    an output unit which outputs information processed by the image signal processing unit;

    wherein the first detection optical unit includes a spatial filter which cuts off light reflected from patterns formed on the object; and

    wherein the second detection optical unit includes a variable spatial filter which cuts off light reflected from patterns formed on the object.

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