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Apparatus for testing a bonding position of a bonding wire

  • US 5,745,594 A
  • Filed: 10/04/1995
  • Issued: 04/28/1998
  • Est. Priority Date: 12/28/1992
  • Status: Expired due to Fees
First Claim
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1. An apparatus for determining a bonding position of a bonding wire, comprising:

  • imaging means, situated above an object, for imaging the object, the object including a member and the bonding wire bonded to the member;

    first illumination means, situated above the object, for emitting light to the object;

    second illumination means, situated below the object, for emitting light to the object;

    image processing means including a memory unit for storing an image obtained by said imaging means and a processing unit for logically processing said image;

    first power supply means for supplying power to operate the first illumination means;

    second power supply means for supplying power to operate the second illumination means; and

    control means for controlling the operations of said image processing means, said first power supply means and said second power supply means;

    said control means including;

    data input means for presetting a number of executions (X;

    a plural number) of a logical process, each execution comprising a scan of an image pixel-by-pixel, the logical process including an enlargement filtering process and a reduction filtering process;

    means for obtaining a first image consisting of an image portion of the member, which image portion has a first brightness, and another image portion having a second brightness, by turning on said first power supply means and imaging the object by means of said imaging means;

    means for obtaining a second image consisting of a first image portion of the member and the bonding wire, which first image portion has the second brightness, and a second image portion having the first brightness, by turning on said second power supply means and imaging the object by means of said imaging means;

    means for obtaining a third image including a third image portion of the member, the third image portion alone having the second brightness, by subjecting the second image to the enlargement filtering process (X;

    a plural number) times during which, for each time (X;

    a plural number), the second image is scanned and a center pixel of each group of 3×

    3 pixels of the second image is made to have the first brightness if the eight pixels surrounding the center pixel include at least one pixel with the first brightness;

    means for obtaining a fourth image by subjecting the third image to the reduction filtering process (X;

    a plural number) times during which, for each time (X;

    a plural number), the third image is scanned and the center pixel of each group of 3×

    3 pixels of the third image is made to have the second brightness if the eight pixels surrounding the center pixel include at least one pixel with the second brightness;

    means for obtaining a fifth image including a fifth image portion of the bonding wire on the member, the fifth image portion alone having the first brightness, by combining the first image and the fourth image by one of a NOR process and a NAND process;

    means for obtaining a sixth image including a sixth image portion of a part of the bonding wire in contact with the member, the sixth image portion alone having the first brightness, by subjecting the fifth image to the reduction filtering process (X;

    a plural number) times during which, for each time (X;

    a plural number), the fifth image is scanned and the center pixel of each group of 3×

    3 pixels of the fifth image is made to have the second brightness if the eight pixels surrounding the center pixel include at least one pixel with the second brightness;

    means for obtaining a seventh image by subjecting the sixth image to the enlargement filtering process (X;

    a plural number) times during which, for each time (X;

    a plural number), the sixth image is scanned and the center pixel of each group of 3×

    3 pixels of the sixth image is made to have the first brightness if the eight pixels surrounding the center pixel include at least one pixel with the first brightness, the seventh image comprising an image of the part of the bonding wire in contact with the member and corresponding to the bonding position of the bonding wire; and

    means for detecting the bonding position of the bonding wire on the basis of the seventh image by measuring a center of gravity of a wire collapse portion of the bonding wire.

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