Device manufacturing method, orientation determination method and lithographic apparatus
First Claim
1. A device manufacturing method comprising:
- patterning a beam of radiation using a patterning device;
determining a rotational position orientation of a substrate by;
acquiring an image of each of at least two structures disposed on said substrate;
determining a distance vector in a measurement coordinate system between the at least two structures disposed on said substrate by comparing the respective images of the at least two structures, said at least two structures having corresponding features and of which relative positions are known in relation to a pattern coordinate system different from the measurement coordinate system;
decomposing the distance vector into a first distance along a first axis of the measurement coordinate system and a second distance along a second axis of the measurement coordinate system; and
calculating a rotational position of the pattern coordinate system in relation to the measurement coordinate system using the first and the second distance; and
aligning the substrate and the patterning device according to the rotational position orientation of the substrate; and
projecting the patterned beam of radiation onto a target portion of a layer of radiation-sensitive material disposed on the substrate.
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Abstract
A method to determine a rotation of a substrate with respect to the patterning device without using a reference mark on the substrate is presented. At least two structures having corresponding features and present on the substrate, e.g. previously projected patterns, are imaged with a known position with respect to a measurement coordinate system. A distance vector between the at least two structures is determined. From the distance vector, a rotation angle is calculated. In an embodiment of the invention, there is provided a method to estimate a position of the substrate from the acquired image(s). A position is measured and used as a reference position for subsequent substrates of which the rotation angle is to be determined.
38 Citations
16 Claims
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1. A device manufacturing method comprising:
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patterning a beam of radiation using a patterning device; determining a rotational position orientation of a substrate by; acquiring an image of each of at least two structures disposed on said substrate; determining a distance vector in a measurement coordinate system between the at least two structures disposed on said substrate by comparing the respective images of the at least two structures, said at least two structures having corresponding features and of which relative positions are known in relation to a pattern coordinate system different from the measurement coordinate system; decomposing the distance vector into a first distance along a first axis of the measurement coordinate system and a second distance along a second axis of the measurement coordinate system; and calculating a rotational position of the pattern coordinate system in relation to the measurement coordinate system using the first and the second distance; and aligning the substrate and the patterning device according to the rotational position orientation of the substrate; and projecting the patterned beam of radiation onto a target portion of a layer of radiation-sensitive material disposed on the substrate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for determining a rotational position of an object within a lithographic apparatus having an illumination system, a support structure, a substrate table, and a projection system, the method comprising:
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determining a distance vector in a measurement coordinate system between two structures on the object by comparing an image of each of the structures said structures each having corresponding features and of which relative positions are known in relation to a pattern coordinate system different than the measurement coordinate system; decomposing the distance vector into a first distance along a first axis of the measurement coordinate system and a second distance along a second axis of the measurement coordinate system; calculating a rotational position of the pattern coordinate system in relation to the measurement coordinate system using the first and the second distance, and aligning the object in the lithographic system according to the rotational position.
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12. A lithographic apparatus comprising:
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an illumination system configured to condition a beam of radiation; a support structure configured to support a patterning device, the patterning device serving to pattern the beam of radiation according to a desired pattern; a substrate table configured to hold a substrate; a projection system configured to project the patterned beam of radiation onto a target portion of the substrate; and an alignment system to align said substrate with said patterning device, wherein the alignment system must acquire an image of each of two structures disposed on said substrate, compare an image of each of the two structures to determine a distance vector in a measurement coordinate system between the two structures disposed on said substrate, said two structures having corresponding features and of which relative positions are known in relation to a pattern coordinate system different than the measurement coordinate system, decompose the distance vector into a first distance along a first axis of the measurement coordinate system and a second distance along a second axis of the measurement coordinate system, and calculate a rotational position of the pattern coordinate system in relation to the measurement coordinate system using the first and the second distance.
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13. A method for aligning a substrate in a lithographic apparatus comprising:
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acquiring images of first and second corresponding structures to determine a first distance vector between the first and the second corresponding structures in a measurement coordinate system of the lithographic apparatus, the first and second corresponding structures being located on two adjacent target portions of the substrate; determining a second distance vector between the first and second corresponding structures in a pattern coordinate system different than the measurement coordinate system; determining a rotational position angle of the pattern coordinate system relative to the measurement coordinate system using the first and the second distance vector, and aligning the substrate in the lithographic apparatus according to the rotational position angle. - View Dependent Claims (14, 15, 16)
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Specification