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Methods for continuous embedded process monitoring and optical inspection of substrates using specular signature analysis

  • US 6,882,416 B1
  • Filed: 10/06/2000
  • Issued: 04/19/2005
  • Est. Priority Date: 09/07/1999
  • Status: Expired due to Fees
First Claim
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1. A method for inspecting a surface of a substrate, the method comprising:

  • illuminating at least a portion of the surface with an optical signal emitted from a light source;

    receiving, at a detector unit, a portion of the optical signal from the surface;

    generating, at a processing unit connected to the detector unit, signal signature information for the substrate representing characteristics of the portion of the optical signal;

    determining a mean value of the signal signature information;

    subtracting the mean value of the signal signature information from a reference mean value; and

    determining a topographical condition of the surface based on the difference between the mean value of the signal signature information and the reference mean value, wherein the signal signature information is indicative of process uniformity on the surface of the substrate.

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