Apparatus for SLM-based optical lithography with gray level capability
First Claim
1. A lithographic tool, comprising:
- a spatial light modulator, said spatial light modulator comprising an area array of individually switchable elements, said elements of said spatial light modulator being arranged in rows and columns on a rectangular grid;
a light source configured to continuously illuminate said spatial light modulator;
imaging optics configured to continuously project an image of said spatial light modulator on a photosensitive material, said photosensitive material comprising an area array of pixels, the size and configuration of said pixels corresponding to the projected spacing and configuration of individually switchable elements in said spatial light modulator, wherein said photosensitive material coats the surface of a substrate;
a control system configured to control switching of said individually switchable elements of said spatial light modulator for defining features in said photosensitive material, said switching being between at least two states, wherein a first state allows light to reach said photosensitive material and a second state stops light from reaching said photosensitive material; and
a stage configured to move said substrate relative to said projected image, whereby a pixel in said photosensitive material receives, in serial, doses of energy from multiple elements of said spatial light modulator;
wherein the direction of movement of said substrate is neither parallel nor orthogonal to said columns of said elements of said spatial light modulator and wherein said control system is further configured to control switching of said elements of said spatial light modulator to vary the number of elements of said spatial light modulator that serially contribute to a total dose of energy received by any pixel in said photosensitive material, whereby some pixels in said photosensitive material receive different, non-zero, total doses of energy.
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Abstract
An optical lithography system comprises a light source, a spatial light modulator, imaging optics and means for continuously moving a photosensitive substrate relative to the spatial light modulator. The spatial light modulator comprises at least one array of individually switchable elements. The spatial light modulator is continuously illuminated and an image of the spatial light modulator is continuously projected on the substrate; consequently, the image is constantly moving across the surface of the substrate. While the image is moving across the surface, elements of the spatial light modulator are switched such that a pixel on the surface of the substrate receives, in serial, doses of energy from multiple elements of the spatial light modulator, thus forming a latent image on the substrate surface. The imaging optics is configured to project a blurred image of the spatial light modulator on the substrate, enabling sub-pixel resolution feature edge placement.
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Citations
24 Claims
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1. A lithographic tool, comprising:
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a spatial light modulator, said spatial light modulator comprising an area array of individually switchable elements, said elements of said spatial light modulator being arranged in rows and columns on a rectangular grid; a light source configured to continuously illuminate said spatial light modulator; imaging optics configured to continuously project an image of said spatial light modulator on a photosensitive material, said photosensitive material comprising an area array of pixels, the size and configuration of said pixels corresponding to the projected spacing and configuration of individually switchable elements in said spatial light modulator, wherein said photosensitive material coats the surface of a substrate; a control system configured to control switching of said individually switchable elements of said spatial light modulator for defining features in said photosensitive material, said switching being between at least two states, wherein a first state allows light to reach said photosensitive material and a second state stops light from reaching said photosensitive material; and a stage configured to move said substrate relative to said projected image, whereby a pixel in said photosensitive material receives, in serial, doses of energy from multiple elements of said spatial light modulator; wherein the direction of movement of said substrate is neither parallel nor orthogonal to said columns of said elements of said spatial light modulator and wherein said control system is further configured to control switching of said elements of said spatial light modulator to vary the number of elements of said spatial light modulator that serially contribute to a total dose of energy received by any pixel in said photosensitive material, whereby some pixels in said photosensitive material receive different, non-zero, total doses of energy. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A lithographic tool, comprising:
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a spatial light modulator, said spatial light modulator comprising an area array of individually switchable elements; a light source configured to continuously illuminate said spatial light modulator; imaging optics configured to project an image of said spatial light modulator on a photosensitive material, said photosensitive material comprising an area array of pixels, the size and configuration of said pixels corresponding to the projected spacing and configuration of individually switchable elements in said spatial light modulator; a control system configured to control switching of said individually switchable elements of said spatial light modulator for defining features in said photosensitive material, said switching being between at least two states, wherein a first state allows light to reach said photosensitive material and a second state stops light from reaching said photosensitive material; and a stage configured to move said substrate relative to said projected image, whereby a pixel in said photosensitive material receives, in serial, doses of energy from multiple elements of said spatial light modulator; wherein said stage and said imaging optics are further configured to provide a defocused image of said spatial light modulator on said photosensitive material, and wherein said control system is further configured to control switching of said elements of said spatial light modulator to vary the number of elements of said spatial light modulator that serially contribute to the total dose of energy received by any pixel in said photosensitive material, whereby some pixels in said photosensitive material receive different, non-zero, total doses of energy. - View Dependent Claims (18, 19)
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20. A lithographic tool, comprising:
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a spatial light modulator, said spatial light modulator comprising an area array of individually switchable elements; a light source configured to continuously illuminate said spatial light modulator; imaging optics configured to project an image of said spatial light modulator on a photosensitive material, said photosensitive material comprising an area array of pixels, the size and configuration of said pixels corresponding to the projected spacing and configuration of individually switchable elements in said spatial light modulator, wherein said photosensitive material coats the surface of a substrate; a control system configured to control switching of said individually switchable elements of said spatial light modulator for defining features in said photosensitive material, said switching being between at least two states, wherein a first state allows light to reach said photosensitive material and a second state stops light from reaching said photosensitive material; and a stage configured to move said substrate relative to said projected image, whereby a pixel in said photosensitive material receives, in serial, doses of energy from multiple elements of said spatial light modulator; wherein said imaging optics is further configured to project a blurred image of said spatial light modulator on said photosensitive material, and wherein said control system is further configured to control switching of said elements of said spatial light modulator to vary the number of elements of said spatial light modulator that serially contribute to the total dose of energy received by any pixel in said photosensitive coating, whereby some pixels in said photosensitive material receive different, non-zero, total doses of energy. - View Dependent Claims (21, 22, 23, 24)
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Specification