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Optical diffraction method and apparatus for integrated circuit lead inspection

  • US 5,663,799 A
  • Filed: 01/24/1996
  • Issued: 09/02/1997
  • Est. Priority Date: 01/24/1996
  • Status: Expired due to Fees
First Claim
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1. A method for detecting damage of leads arranged in a generally parallel periodic pattern, comprising the steps of:

  • (a) directing a coherent light beam at a plurality of adjacent leads;

    (b) detecting an image at a distance from the leads at which said light beam would form a diffraction image having substantially uniform intensity when said leads form a substantially uniform pattern;

    (c) moving said pattern of leads and said light beam with respect to each other; and

    (d) detecting damage of leads from variation in intensity of the detected image.

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