Lithographic apparatus, method of calibration, calibration plate, device manufacturing method, and device manufactured thereby
First Claim
1. A method of calibration, said method comprising:
- moving a marker of a calibration plate to an alignment position;
using a height sensor to measure a first height profile of the calibration plate;
subsequent to said moving a marker and said using a height sensor to measure a first height profile, rotating the calibration plate by substantially 180 degrees;
subsequent to said rotating, moving the marker to the alignment position again;
subsequent to said rotating, using the height sensor to measure a second height profile of the calibration plate; and
determining a position of a measurement spot of the height sensor with respect to the alignment position, based on the first and second height profiles.
1 Assignment
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Accused Products
Abstract
A method according to one embodiment of the invention may be performed using a calibration plate having at least one alignment marker and at least one height profile. First, the calibration plate is positioned using an alignment sensor. Then the height profile is measured by a height sensor. Then the calibration plate is rotated by substantially 180 degrees and the two operations are repeated. This procedure results in two measured height profiles, which are compared in order to find a best fit. The amount of shift performed to find the best fit is used to determine a distance between the alignment marker and the X,Y position of the measurement point of the height sensor.
18 Citations
31 Claims
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1. A method of calibration, said method comprising:
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moving a marker of a calibration plate to an alignment position;
using a height sensor to measure a first height profile of the calibration plate;
subsequent to said moving a marker and said using a height sensor to measure a first height profile, rotating the calibration plate by substantially 180 degrees;
subsequent to said rotating, moving the marker to the alignment position again;
subsequent to said rotating, using the height sensor to measure a second height profile of the calibration plate; and
determining a position of a measurement spot of the height sensor with respect to the alignment position, based on the first and second height profiles. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A calibration plate comprising:
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an alignment marker;
a first plane; and
a second plane sloped with respect to the first plane. - View Dependent Claims (25, 26, 27)
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28. A device manufacturing method, said method comprising:
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moving a marker of a calibration plate to an alignment position;
using a height sensor to measure a first height profile of the calibration plate;
subsequent to said moving a marker and said using a height sensor to measure a first height profile, rotating the calibration plate by substantially 180 degrees;
subsequent to said rotating, moving the marker to the alignment position again;
subsequent to said rotating, using the height sensor to measure a second height profile of the calibration plate;
determining a position of a measurement spot of the height sensor with respect to the alignment position, based on the first and second height profiles;
using a radiation system to provide a beam of radiation;
using a patterning structure to pattern the beam of radiation according to a desired pattern; and
projecting the patterned beam onto a target portion of a layer of radiation-sensitive material that at least partially covers a substrate, wherein said projecting includes positioning the substrate based on said determining a position of the measurement spot of the height sensor. - View Dependent Claims (29, 30)
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31. A method of calibration, said method comprising:
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providing a calibration plate having at least one alignment marker;
positioning the calibration plate in a lithographic apparatus using an alignment sensor, such that the alignment marker is in a first X,Y position and a measurement point of a height sensor of the lithographic apparatus corresponds to a second X,Y position;
measuring a first height profile of the calibration plate using the height sensor;
rotating the calibration plate by substantially 180 degrees;
subsequent to said rotating, positioning the calibration plate in the lithographic apparatus using the alignment sensor, such that the alignment marker is in the first X,Y position and the measurement point of the height sensor corresponds to the second X,Y position;
subsequent to said rotating, measuring a second height profile of the calibration plate using the height sensor;
calculating a difference between the first and second X,Y positions based on the first and second height profiles; and
calibrating the height sensor based on the difference.
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Specification