Method and apparatus for determining surface layer thickness using continuous multi-wavelength surface scanning

  • US 20050018183A1
  • Filed: 01/09/2004
  • Published: 01/27/2005
  • Est. Priority Date: 07/23/2003
  • Status: Active Grant
First Claim
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1. A surface inspection apparatus comprising:

  • an illumination element for directing at least two light beams onto a surface to generate a reflected light signal and a scattered light signal for each of the at least two light beams, the at least two light beams having one of;

    at least two different wavelengths or at least two different angles of incidence from the surface;

    optical detectors configured to receive the reflected light signals; and

    circuitry for analyzing the reflected light signals to determine thickness values for the partially transmissive layer.

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