System and method for printing interference patterns having a pitch in a lithography system
First Claim
1. An interferometric lithography apparatus, comprising along an optical path:
- a beam splitter to create at least two spatially coherent radiation beams;
a beam combiner adapted to redirect and combine the at least two spatially coherent radiation beams onto a surface of a substrate to form an interference pattern;
a field blade, at an object plane, that is separate from the beam splitter and located on, or downstream from, the beam splitter; and
a lens to image a border of the field blade onto the surface of the substrate so as to create the border of the interference pattern.
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Accused Products
Abstract
An interferometric lithography system produces a pattern having a sharp field edge and minimal optical path length difference. Light passes through a beamsplitter into an input prism. The two beams produced by the beamsplitter are reflected off respective surfaces of the input prism toward a substrate prism. The substrate prism is symmetric to the input prism such that the incidence angle at an image plane is approximately equal to the beamsplitter diffraction angle. Alternatively, light passes through a beamsplitter into a prism. The two beams produced by the beamsplitter are reflected off respective surfaces of the prism toward an output surface of the prism, such that the incidence angle at the output surface is approximately equal to the beamsplitter diffraction angle. A plurality of these interferometers can be stacked, each being optimized for a given pitch, such that the stack provides a variable pitch interferometry system.
63 Citations
20 Claims
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1. An interferometric lithography apparatus, comprising along an optical path:
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a beam splitter to create at least two spatially coherent radiation beams; a beam combiner adapted to redirect and combine the at least two spatially coherent radiation beams onto a surface of a substrate to form an interference pattern; a field blade, at an object plane, that is separate from the beam splitter and located on, or downstream from, the beam splitter; and a lens to image a border of the field blade onto the surface of the substrate so as to create the border of the interference pattern. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An interferometric lithography apparatus, comprising:
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a beam splitter to create at least two spatially coherent radiation beams at a first plane; a beam combiner adapted to redirect and combine the at least two spatially coherent radiation beams onto a surface of a substrate to form an interference pattern at a second plane; a first afocal imaging branch provided with a lens, the first afocal imaging branch having substantially unit magnification; a second afocal imaging branch provided with a lens, the second afocal imaging branch having substantially unit magnification; and four reflecting surfaces between the beam splitter and an output surface of the beam combiner which faces the surface of the substrate, wherein, during use, each of the at least two spatially coherent radiation beams are reflected from two of the four reflecting surfaces in series and each of the at least two spatially coherent radiation beams are reflected and converged by two of the four reflecting surfaces in parallel and the first and second planes are substantially optically conjugate. - View Dependent Claims (12, 13, 14, 15)
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16. An interferometric lithography apparatus having variable pitch, comprising:
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an illumination system; a first interferometer to form an interference pattern having a first pitch; and a second interferometer to form an interference pattern having a second pitch, the second interferometer comprising; a beam splitter to create at least two spatially coherent radiation beams at a first plane; a beam combiner adapted to redirect and combine the at least two spatially coherent radiation beams onto a surface of a substrate to form the interference pattern at a second plane; a first afocal imaging branch provided with a lens, the first afocal imaging branch having substantially unit magnification; a second afocal imaging branch provided with a lens, the second afocal imaging branch having substantially unit magnification; and four reflecting surfaces between the beam splitter and an output surface of the beam combiner which faces the surface of the substrate, wherein, during use, each of the at least two spatially coherent radiation beams are reflected from two of the four reflecting surfaces in series and each of the at least two spatially coherent radiation beams are reflected and converged by two of the four reflecting surfaces in parallel and the first and second planes are substantially optically conjugate, wherein the first and second interferometers are movable with respect to the illumination system such that radiation from the illumination system is incident on one of the first and second interferometers. - View Dependent Claims (17, 18, 19, 20)
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Specification