×

Method for controlling growth of a silicon crystal

  • US 5,882,402 A
  • Filed: 09/30/1997
  • Issued: 03/16/1999
  • Est. Priority Date: 09/30/1997
  • Status: Expired due to Term
First Claim
Patent Images

1. A method for use in combination with an apparatus for growing a silicon single crystal, said crystal growing apparatus having a heated crucible containing a silicon melt from which the crystal is pulled, said melt having a surface with a meniscus visible as a bright area adjacent the crystal as the crystal is pulled from the melt, said method for determining a diameter of the crystal, said method comprising the steps of:

  • generating an image with a camera of the interior of the crucible including a portion of the bright area adjacent the crystal, said image including a plurality of pixels, said pixels each having a value representative of an optical characteristic of the image;

    defining a central window region of the image at a position corresponding to an approximate center of the crystal, said central window region having an elliptical shape;

    processing the image as a function of the pixel values to detect edges within the central window region;

    grouping the detected edges to define an object in the image corresponding to the crystal;

    determining a dimension of the defined object; and

    determining an approximate diameter of the crystal as a function of the determined dimension of the defined object.

View all claims
  • 17 Assignments
Timeline View
Assignment View
    ×
    ×