Method of determining overlay error and control system for dynamic control of reticle position
First Claim
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1. A method of reducing overlay error comprising:
- transferring a pattern of features from a reticle to a wafer;
measuring a positional difference between the pattern on the reticle and the pattern on the wafer at a first set of data points;
determining a second set of data points based on the first set of data points, the second set of data points being a subset of the first set of data points, wherein a position of the second set of data points is indicative of a position of at least one of the first set of data points, and a number of the first set of data points is greater than a number of the second set of data points; and
changing a position of the reticle to minimize the positional difference based on the second set of data points,wherein the second set of data points comprises at least one region data point and at least one variable data point.
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Abstract
A method of determining overlay error. The method includes transferring a pattern from a reticle to a wafer and selecting a first set of data points to measure the positional difference between features on the reticle and features on the wafer. The method also includes determining a second set of data points characteristic of the first set of data points but containing fewer data points. A control system for using the second set of data points to dynamically adjust the position of the reticle.
13 Citations
20 Claims
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1. A method of reducing overlay error comprising:
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transferring a pattern of features from a reticle to a wafer; measuring a positional difference between the pattern on the reticle and the pattern on the wafer at a first set of data points; determining a second set of data points based on the first set of data points, the second set of data points being a subset of the first set of data points, wherein a position of the second set of data points is indicative of a position of at least one of the first set of data points, and a number of the first set of data points is greater than a number of the second set of data points; and changing a position of the reticle to minimize the positional difference based on the second set of data points, wherein the second set of data points comprises at least one region data point and at least one variable data point. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of reducing overlay error comprising:
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transferring a pattern of features from a reticle to a wafer; measuring a positional difference between the pattern on the reticle and the pattern on the wafer at a first set of data points; changing a position of the reticle to minimize the positional difference based on a second set of data points, the second set of data points being a selected subset of the first set of data points; and positioning at least one data point of the first set of data points within a regional boundary defining a predetermined region of a plurality of regions, wherein the second set of data points comprises at least one region data point and a remainder of the data points of the second set of data points comprises at least one variable data point. - View Dependent Claims (14, 15, 16, 17)
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18. A method of reducing overlay error comprising:
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transferring a pattern of features from a reticle to a wafer; measuring a positional difference between the pattern on the reticle and the pattern on the wafer at a first set of data points; and moving the reticle to change the positional difference based on a second set of data points, the second set of data points being a subset of the first set of data points, wherein the second set of data points comprises at least one region data point and at least one variable data point, and a total quantity of region data points and variable data points is equal to a total quantity of data points of the second set of data points. - View Dependent Claims (19, 20)
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Specification