Stage alignment in lithography tools
First Claim
1. A lithography system, comprising:
- a stage for supporting a wafer;
an illumination system including a radiation source and a lens assembly, wherein the illumination system is configured to direct radiation through a mask to produce spatially patterned radiation, and the lens assembly is configured to image the spatially patterned radiation onto the wafer;
a first interferometry system configured to monitor a location of the stage within the lithography system as the stage moves relative to the illumination system;
a second interferometry system comprising an interferometer configured to direct two beams from a common light source along different paths to a surface associated with the stage, the second interferometry systems being configured to identify an alignment feature on the surface associated with the stage based on an output beam formed from light from the two beams specularly reflected from the alignment feature; and
an electronic controller coupled to the interferometry systems, wherein the electronic controller is configured to determine information about a location of the stage when the alignment feature is identified.
1 Assignment
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Accused Products
Abstract
In general, in a first aspect, the invention features a lithography system that includes a stage for supporting a wafer, an illumination system including a radiation source and a lens assembly, wherein the illumination system is configured to direct radiation through a mask to produce spatially patterned radiation, and the lens assembly is configured to image the spatially patterned radiation onto the wafer, a first interferometry system configured to monitor a location of the stage within the lithography system as the stage moves relative to the illumination system, a second interferometry system configured to identify an alignment feature on a surface associated with the stage, and an electronic controller coupled to the interferometry systems, wherein the electronic controller is configured to determine information about a location of the stage when the alignment feature is identified.
68 Citations
39 Claims
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1. A lithography system, comprising:
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a stage for supporting a wafer; an illumination system including a radiation source and a lens assembly, wherein the illumination system is configured to direct radiation through a mask to produce spatially patterned radiation, and the lens assembly is configured to image the spatially patterned radiation onto the wafer; a first interferometry system configured to monitor a location of the stage within the lithography system as the stage moves relative to the illumination system; a second interferometry system comprising an interferometer configured to direct two beams from a common light source along different paths to a surface associated with the stage, the second interferometry systems being configured to identify an alignment feature on the surface associated with the stage based on an output beam formed from light from the two beams specularly reflected from the alignment feature; and an electronic controller coupled to the interferometry systems, wherein the electronic controller is configured to determine information about a location of the stage when the alignment feature is identified. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An interferometry system for identifying an alignment feature on a surface associated with a stage within a lithography tool, the interferometry system comprising:
an interferometer configured to direct two beams derived from a common light source along different paths and to combine light from the two beams that is specularly reflected from the alignment feature to form an output beam comprising information about the location of the alignment feature with respect to the two beams. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. A method, comprising:
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directing two beams derived from a common source along different paths to contact a surface associated with a wafer stage; and combining light from the two beams that is specularly reflected from an alignment feature in the surface to form an output beam comprising information about the location of the alignment feature with respect to the two beams.
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34. A method, comprising:
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monitoring a location of a stage within the lithography system comprising an illumination system as the stage moves relative to an illumination system; using an interferometry system to identify an alignment feature on a surface associated with the stage by directing two beams derived from a common source along different paths to contact the surface associated with the stage and monitoring an output beam formed from light from the two beams specularly reflected from the alignment feature; and determining information about a location of the stage within the lithography system when the alignment feature is identified.
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35. A lithography system, comprising:
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a stage for supporting a wafer; an illumination system including a radiation source and a lens assembly, wherein the illumination system is configured to direct radiation through a mask to produce spatially patterned radiation, and the lens assembly is configured to image the spatially patterned radiation onto the wafer; a first interferometry system configured to monitor a location of the stage within the lithography system as the stage moves relative to the illumination system; a second interferometry system comprising an interferometer configured to direct two beams from a common light source along different paths to a surface associated with the stage, the second interferometry systems being configured to identify an alignment feature, on the surface associated with the stage based on an output beam formed from light from the two beams reflected from the alignment feature; and an electronic controller coupled to the interferometry systems, wherein the electronic controller is configured to determine information about a location of the stage when the alignment feature is identified; wherein the second interferometry system comprises an optical element that is configured to both direct the light from one of the two beams toward the alignment feature and receive light reflected from the alignment feature, where the second interferometer forms the output beam using light reflected from the alignment feature received by the optical element. - View Dependent Claims (36)
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37. A lithography system, comprising:
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a stage for supporting a wafer; an illumination system including a radiation source and a lens assembly, wherein the illumination system is configured to direct radiation through a mask to produce spatially patterned radiation, and the lens assembly is configured to image the spatially patterned radiation onto the wafer; a first interferometry system configured to monitor a location of the stage within the lithography system as the stage moves relative to the illumination system; a second interferometry system comprising an interferometer configured to direct two beams from a common light source along different paths to a surface associated with the stage, the second interferometry systems being configured to identify an alignment feature on the surface associated with the stage based on an output beam formed from light from the two beams reflected from the alignment feature; and an electronic controller coupled to the interferometry systems, wherein the electronic controller is configured to determine information about a location of the stage when the alignment feature is identified; wherein the common light source is a broadband light source.
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38. A lithography system, comprising:
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a stage for supporting a wafer; an illumination system including a radiation source and a lens assembly, wherein the illumination system is configured to direct radiation through a mask to produce spatially patterned radiation, and the lens assembly is configured to image the spatially patterned radiation onto a surface of the wafer; a first interferometry system configured to monitor a location of the stage within the lithography system as the stage moves relative to the illumination system; a second interferometry system comprising an interferometer configured to direct a first beam and a second beam from a common light source along different paths to a surface associated with the stage, the second interferometry systems being configured to identify an alignment feature on the surface associated with the stage based on an output beam formed from light from the first and second beams reflected from the alignment feature; and an electronic controller coupled to the interferometry systems, wherein the electronic controller is configured to determine information about a location of the stage along a first axis when the alignment feature is identified; wherein the alignment feature comprises a first facet and a second facet opposite the first facet, wherein the first and second facets are non-parallel to the surface of the wafer and have an area larger than a cross sectional area of the first and second beams, respectively, at the surface. - View Dependent Claims (39)
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Specification