Multiple-pass interferometry
First Claim
1. Apparatus comprising:
- a multiple-pass interferometer including reflectors to reflect at least two beams along multiple passes through the interferometer, the multiple passes including a first set of passes and a second set of passes, the reflectors having first alignments that are normal to the directions of the paths of the beams that are reflected by the reflectors, the paths of the beams being sheared during the first set of passes and during the second set of passes if at least one of the reflectors has an alignment other than the first alignment, and optics to redirect the beams after the first set of passes and before the second set of passes so that shear imparted during the second set of passes cancels shear imparted during the first set of passes.
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Accused Products
Abstract
Interferometry system including a multiple-pass interferometer having reflectors to reflect at least two beams along multiple passes through the interferometer, the multiple passes including a first set of passes and a second set of passes, the reflectors having first alignments that are normal to the directions of the paths of the beams that are reflected by the reflectors, the paths of the beams being sheared during the first set of passes and during the second set of passes if at least one of the reflectors has an alignment other than the first alignment, and optics to redirect the beams after the first set of passes and before the second set of passes so that shear imparted during the second set of passes cancels shear imparted during the first set of passes.
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Citations
70 Claims
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1. Apparatus comprising:
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a multiple-pass interferometer including reflectors to reflect at least two beams along multiple passes through the interferometer, the multiple passes including a first set of passes and a second set of passes, the reflectors having first alignments that are normal to the directions of the paths of the beams that are reflected by the reflectors, the paths of the beams being sheared during the first set of passes and during the second set of passes if at least one of the reflectors has an alignment other than the first alignment, and optics to redirect the beams after the first set of passes and before the second set of passes so that shear imparted during the second set of passes cancels shear imparted during the first set of passes. - 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, 24, 25, 26, 27, 28, 29, 30, 42, 43, 44, 45, 46, 47)
a stage to support a wafer for fabricating integrated circuits thereon;
an illumination system to image spatially patterned radiation onto the wafer; and
a positioning system to adjust the position of the stage relative to the imaged radiation, in which the interferometer is used to measure the position of the stage.
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29. The apparatus of claim 1 further comprising:
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a stage to support a wafer for fabricating integrated circuits thereon; and
an illumination system including a radiation source, a mask, a positioning system, and a lens assembly in which during operation the source directs radiation through the mask to produce spatially patterned radiation, the positioning system adjusts the position of the mask relative to the radiation from the source, the lens assembly images the spatially patterned radiation onto the wafer, and the interferometer is used to measure the position of the mask relative to the wafer.
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30. The apparatus of claim 1 further comprising:
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a source to provide a write beam to pattern a substrate, a stage to support the substrate, a beam directing assembly to deliver the write beam to the substrate, and a positioning system to position the stage and beam directing assembly relative to one another, in which the interferometer is used to measure the position of the stage relative to the beam directing assembly.
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42. A lithography system for fabricating integrated circuits on a wafer, comprising:
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a stage to support the wafer;
an illumination system to image spatially patterned radiation onto the wafer; and
a positioning system to adjust the position of the stage relative to the imaged radiation; and
the apparatus of claim 1 to measure the position of the stage along a first degree of freedom.
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43. The lithography system of claim 42, further comprising a second one of the apparatus of claim 1 to measure the position of the stage along a second degree of freedom.
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44. A lithography system for fabricating integrated circuits on a wafer, comprising:
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a stage to support the wafer; and
an illumination system including a radiation source, a mask, a positioning system, a lens assembly, and the apparatus of claim 1 in which during operation the source directs radiation through the mask to produce spatially patterned radiation, the positioning system adjusts the position of the mask relative to the radiation from the source, the lens assembly images the spatially patterned radiation onto the wafer, and the apparatus is used to measure the position of the mask relative to the wafer along a first degree of freedom.
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45. The lithography system of claim 44 further comprising a second one of the apparatus of claim 1 to measure the position of the stage along a second degree of freedom.
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46. A beam writing system, comprising:
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a source to provide a write beam to pattern a substrate, a stage to support the substrate, a beam directing assembly to deliver the write beam to the substrate, and a positioning system to position the stage and beam directing assembly relative one another; and
the apparatus of claim 1 to measure the position of the stage relative to the beam directing assembly along a first degree of freedom.
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47. The beam writing system of claim 46 further comprising a second one of the apparatus of claim 1 to measure the position of the stage along a second degree of freedom.
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31. Apparatus comprising:
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a multiple-pass interferometer including reflectors to reflect at least a first beam along a first path and a second beam along a second path, the first and second paths each including at least a first set of passes and a second set of passes through the interferometer, the reflectors having first alignments that are normal to the directions of the paths of the beams that are reflected by the reflectors, the relative shear between the paths of the beams changes as the beams make the first and second set of passes through the interferometer when at least one of the reflectors has an alignment other than the first alignment, and optics to redirect the beams after the first set of passes and before the second set of passes so that shear imparted during the second set of passes cancels shear imparted during the first set of passes. - View Dependent Claims (32, 33, 34, 35, 36, 37)
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38. Apparatus comprising:
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a multiple-pass interferometer including reflectors to reflect at least two beams along multiple passes through the interferometer, the multiple passes including a first set of passes and a second set of passes, the reflectors having first alignments, the shear between the paths of the two beams changes during the first set of passes and during the second set of passes if one of the reflectors moves from the first alignment to a second alignment different from the first alignment, and optics to redirect the beams after the first set of passes and before the second set of passes so that shear imparted during the second set of passes due to a deviation of one of the reflectors from the first alignment cancels shear imparted during the first set of passes due to the deviation. - View Dependent Claims (39, 40, 41)
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48. A method comprising:
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directing at least two beams along multiple passes through an interferometer, the multiple passes including a first set of passes and a second set of passes, the reflectors having first alignments that are normal to the directions of the paths of the beams that are reflected by the reflectors, and causing shear that is imparted in the first set of passes to be cancelled by shear imparted in the second set of passes by redirecting the beams after the first set of passes and before the second set of passes. - View Dependent Claims (49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 65, 66, 67, 68, 69, 70)
supporting a wafer on a stage;
imaging spatially patterned radiation onto the wafer;
adjusting the position of the stage relative to the imaged radiation; and
measuring the relative position of the stage using the beams that exit the interferometer after the multiple passes.
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60. The method of claim 48 further comprising:
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supporting a wafer on a stage;
directing radiation from a source through a mask to produce spatially patterned radiation;
positioning the mask relative to the wafer;
measuring the position of the mask relative to the wafer using the beams that exit the interferometer after the multiple passes; and
imaging the spatially patterned radiation onto the wafer.
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61. The method of claim 48 further comprising:
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providing a write beam to pattern a substrate;
supporting the substrate on a stage;
delivering the write beam to the substrate;
positioning the stage relative to the write beam; and
measuring the relative position of the stage using the beams that exit the interferometer after the multiple passes.
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65. A lithography method for fabricating integrated circuits on a wafer, comprising:
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supporting the wafer on a stage;
imaging spatially patterned radiation onto the wafer;
adjusting the position of the stage relative to the imaged radiation; and
measuring the relative position of the stage along a first degree of freedom using the method of claim 48.
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66. The lithography method of claim 65 further comprising using the method of claim 48 to measure the relative position of the stage along a second degree of freedom.
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67. A lithography method for fabricating integrated circuits on a wafer, comprising:
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supporting the wafer on a stage;
directing radiation from a source through a mask to produce spatially patterned radiation;
positioning the mask relative to the wafer;
measuring the position of the mask relative to the wafer along a first degree of freedom using the method of claim 48; and
imaging the spatially patterned radiation onto the wafer.
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68. The lithography method of claim 67 further comprising using the method of claim 48 to measure the relative position of the mask along a second degree of freedom.
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69. A lithography method for fabricating a photolithography mask, comprising:
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providing a write beam to pattern a substrate;
supporting the substrate on a stage;
delivering the write beam to the substrate;
positioning the stage relative to the write beam; and
measuring the relative position of the stage along a first degree of freedom using the method of claim 48.
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70. The lithography method of claim 69 further comprising using the method of claim 48 to measure the relative position of the stage along a second degree of freedom.
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62. A method comprising:
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directing at least two beams along multiple passes through an interferometer, the multiple passes including a first set of passes and a second set of passes, the reflectors having first alignments, and redirecting the two beams after the first set of passes and before the second set of passes to cause shear that is imparted in the first set of passes caused by one of the reflectors moving from the first alignment to a second alignment to be cancelled by shear imparted in the second set of passes caused by the movement of the reflector from the first alignment to the second alignment. - View Dependent Claims (63, 64)
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Specification