Method for selecting reference images, method and apparatus for inspecting patterns on wafers, and method for dividing a wafer into application regions
First Claim
1. A method of selecting reference images comprising:
- determining a tolerance for a difference between gray levels of dies located on a wafer;
selecting a first die and at least one second die;
obtaining images of the first die and the at least one second die;
measuring the gray levels of the images obtained from the first die and the at least one second die;
determining a difference in the measured gray levels of the first die and the at least one second die; and
selecting at least one reference image;
wherein one image selected from the images obtained from the first die and the at least one second die is selected as the reference image when the difference between the measured gray levels is within the tolerance; and
wherein the image obtained from the first die and one of the images obtained from the at least one second die are selected as reference images when the difference between the measured gray levels is not within the tolerance.
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Abstract
A method for selecting reference images, a method and an apparatus for inspecting patterns on a wafer, and a method for dividing a wafer into application regions. In a method for inspecting patterns according to at least one exemplary embodiment of the present invention, a plurality of reference dies may be selected and a difference in gray levels of images of the references dies may be determined. The reference dies may include a first die substantially centrally located on the wafer and at least one second die located at an edge portion of the wafer. One reference image is selected if the difference in gray levels is within a permitted tolerance and more than one reference image may be selected if the difference in gray levels is not within the permitted tolerance. A pattern inspection may be performed using the reference images.
79 Citations
42 Claims
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1. A method of selecting reference images comprising:
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determining a tolerance for a difference between gray levels of dies located on a wafer;
selecting a first die and at least one second die;
obtaining images of the first die and the at least one second die;
measuring the gray levels of the images obtained from the first die and the at least one second die;
determining a difference in the measured gray levels of the first die and the at least one second die; and
selecting at least one reference image;
wherein one image selected from the images obtained from the first die and the at least one second die is selected as the reference image when the difference between the measured gray levels is within the tolerance; and
wherein the image obtained from the first die and one of the images obtained from the at least one second die are selected as reference images when the difference between the measured gray levels is not within the tolerance. - View Dependent Claims (2, 3)
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4. A method for inspecting patterns on wafers comprising:
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determining a tolerance for a difference between gray levels of dies located on a wafer;
selecting a first reference die and at least one second reference die;
obtaining images of the first reference die and the at least one second reference die;
measuring the gray levels of the images obtained from the first reference die and the at least one second reference die;
determining a difference in the measured gray levels of the first reference die and the at least one second reference die;
selecting at least one reference image;
dividing the wafer into application regions, each application region corresponding to a reference image; and
inspecting the dies located in each application region using the reference image corresponding to the application region;
wherein one image selected from the images obtained from the first reference die and the at least one second reference die is selected as the reference image when the difference between the measured gray levels is within the tolerance; and
wherein the image obtained from the first reference die and one of the images obtained from the at least one second reference die are selected as reference images when the difference between the measured gray levels is not within the tolerance. - View Dependent Claims (5, 6)
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7. An apparatus for inspecting patterns on wafers comprising:
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a tolerance setter for determining a tolerance for a difference between gray levels of dies located on a wafer;
a die selector for selecting reference dies;
an image capturing device for obtaining images of the reference dies;
a gray level calibrator for measuring the gray levels of the images of the reference dies;
a gray level comparator for determining a difference in the gray levels;
a reference image selector for selecting at least one reference image; and
a die splitter for dividing the wafer into application regions, each application region corresponding to a reference image. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 38)
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15. A method for inspecting patterns on a wafer comprising:
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selecting a plurality of reference dies;
determining a difference in gray levels of images of the reference dies;
selecting at least one image as a reference image;
performing a pattern inspection using the at least one reference image;
wherein one reference image is selected if the difference in gray levels is within a tolerance and more than one reference image is selected if the difference in gray levels is not within the tolerance. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. An apparatus for inspecting patterns on wafers comprising:
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a die selector for selecting a plurality of reference dies;
a gray level comparator for comparing gray levels of images of the reference dies;
a reference image selector for selecting at least one reference image; and
a pattern inspector for inspecting patterns on a wafer using the at least one reference image. - View Dependent Claims (28, 29, 30, 31, 32, 39)
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33. A method for dividing a wafer into application regions comprising:
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selecting a plurality of reference dies;
determining a difference in gray levels of images of the reference dies;
selecting at least one reference image; and
dividing the wafer into application regions, each application region corresponding to a reference image;
wherein one reference image is selected if the difference in gray levels is within a tolerance and more than one reference image is selected if the difference in gray levels is not within the tolerance. - View Dependent Claims (34, 35, 36, 37)
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40. A method for selecting a reference image comprising:
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selecting a plurality of reference dies;
determining a difference in gray levels of images of the reference dies; and
selecting at least one image as a reference image;
wherein one reference image is selected if the difference in gray levels is within a tolerance and more than one image is selected if the difference in gray levels is not within the tolerance. - View Dependent Claims (41, 42)
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Specification