Substrate, method of preparing a substrate, method of measurement, lithographic apparatus, device manufacturing method and device manufactured thereby, and machine-readable storage medium
First Claim
Patent Images
1. A method of preparing a substrate, said method comprising:
- exposing the substrate with a plurality of images, each of the plurality of images having a different orientation with respect to a crystal axis of the substrate; and
anisotropically etching the substrate to form a plurality of alignment markers, a location of at least a portion of each of the plurality of alignment markers substantially coinciding with a location of a corresponding portion of a corresponding one of the plurality of images, wherein the orientation of each of the plurality of images is within four degrees of the orientation of each other one of the plurality of images.
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Abstract
In a method according to one embodiment of the invention, a plurality of markers are printed in resist on a substrate at a range of angles relative to a crystal axis of the substrate. The markers are etched in to the substrate using an anisotropic etch process, such that after the etch the apparent positions of the markers are dependent on their orientation relative to the crystal axis. The apparent positions of the markers are measured, and from this information the orientation of the crystal axis is derived.
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Citations
28 Claims
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1. A method of preparing a substrate, said method comprising:
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exposing the substrate with a plurality of images, each of the plurality of images having a different orientation with respect to a crystal axis of the substrate; and
anisotropically etching the substrate to form a plurality of alignment markers, a location of at least a portion of each of the plurality of alignment markers substantially coinciding with a location of a corresponding portion of a corresponding one of the plurality of images, wherein the orientation of each of the plurality of images is within four degrees of the orientation of each other one of the plurality of images. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method of preparing a substrate comprising:
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providing on a surface of the substrate a plurality of alignment markers, each of said plurality of alignment markers having a different orientation relative to a crystal axis of the substrate, wherein, for each of said plurality of alignment markers, a distance between an apparent position of the marker and an actual position of an element of the marker is dependent on the orientation of the marker. - View Dependent Claims (9, 10, 11)
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12. A method of determining an orientation of a crystal axis of a substrate, the substrate having provided thereon a plurality of alignment markers, a feature of each of the plurality of alignment markers having a predetermined position, each of the plurality of alignment markers having a different orientation relative to a crystal axis of the substrate, said method comprising:
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measuring a position of each among the plurality of alignment markers;
determining deviations of the measured positions from the corresponding predetermined positions; and
determining the orientation of the crystal axis relative to the plurality of alignment markers from the deviations. - View Dependent Claims (13, 14, 15)
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16. A device manufacturing method, said method comprising:
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providing a beam of radiation;
patterning the beam; 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 controlling an orientation of at least one of the substrate and the projected pattern relative to the other, and wherein said controlling is based on information indicative of an orientation of a crystal axis of the substrate, said information having been determined from a plurality of alignment markers on one among the substrate and another substrate cut from the same crystal. - View Dependent Claims (17, 18, 19, 20, 21)
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22. A lithographic apparatus comprising:
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an illumination system configured to provide a projection beam of radiation;
a patterning structure configured to pattern the projection beam according to a desired pattern;
a substrate table configured to hold a substrate;
a projection system configured to project the patterned beam onto a target portion of the substrate; and
a control system configured to control an orientation of at least one of the substrate and the projected pattern relative to the other based on information indicative of an orientation of a crystal axis of the substrate, said information having been determined from a plurality of alignment markers on one among the substrate and another substrate cut from the same crystal. - View Dependent Claims (23, 24)
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25. A data storage medium having machine-readable information including a set of instructions defining a method of determining an orientation of a crystal axis of a substrate, the substrate having provided thereon a plurality of alignment markers, a feature of each of the plurality of alignment markers having a predetermined position, each of the plurality of alignment markers having a different orientation relative to a crystal axis of the substrate, said method comprising:
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measuring a position of each among the plurality of alignment markers;
determining deviations of the measured positions from the corresponding predetermined positions; and
determining the orientation of the crystal axis relative to the plurality of alignment markers from the deviations.
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26. A substrate comprising a plurality of alignment markers, each of said plurality of alignment markers having a different orientation with respect to a crystal axis of the substrate,
wherein the orientation of each of the plurality of alignment markers is within four degrees of the orientation of each other one of the plurality of alignment markers, and wherein, for each of the plurality of alignment markers, a distance between a moment of the alignment marker and a feature of the alignment marker depends on the orientation of the alignment marker.
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28. A substrate having thereon a plurality of alignment markers at respective predetermined positions, each of the plurality of alignment markers having a different orientation relative to a crystal axis of said substrate, and a form of each of the plurality of alignment markers being such that an apparent position of the alignment marker is dependent on the orientation of the alignment marker.
Specification