GRAY LEVEL METHOD FOR SLM-BASED OPTICAL LITHOGRAPHY
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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.
52 Citations
104 Claims
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1-79. -79. (canceled)
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80. A lithographic method, comprising the steps of:
- continuously illuminating a spatial light modulator, said spatial light modulator comprising an area array of individually switchable elements, wherein said elements of said spatial light modulator are arranged in rows and columns on a rectangular grid;
moving a substrate relative to said spatial light modulator, said substrate having a photosensitive coating, wherein the direction of movement of said substrate is neither parallel nor orthogonal to said columns of said elements of said spatial light modulator; while said substrate is moving, projecting an image of said spatial light modulator on said photosensitive coating, said photosensitive coating 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; and while said substrate is moving, switching said elements of said spatial light modulator, said switching being between at least two states, wherein a first state allows light to reach said substrate and a second state stops light from reaching said substrate, said switching being controlled to define features in said photosensitive coating, whereby, relative to said photosensitive coating, said image of said spatial light modulator moves across said photosensitive coating and a pixel in said photosensitive coating receives, in serial, doses of energy from multiple elements of said spatial light modulator; wherein switching of said elements of said spatial light modulator is controlled 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 coating receive different, non-zero, total doses of energy. - View Dependent Claims (81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97)
- continuously illuminating a spatial light modulator, said spatial light modulator comprising an area array of individually switchable elements, wherein said elements of said spatial light modulator are arranged in rows and columns on a rectangular grid;
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98. A lithographic method, comprising the steps of:
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continuously illuminating a spatial light modulator, said spatial light modulator comprising an area array of individually switchable elements; moving a substrate relative to said spatial light modulator, said substrate having a photosensitive coating; while said substrate is moving, projecting an image of said spatial light modulator on said photosensitive coating, said photosensitive coating 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; while said substrate is moving, switching said elements of said spatial light modulator, said switching being between at least two states, wherein a first state allows light to reach said substrate and a second state stops light from reaching said substrate, said switching being controlled to define features in said photosensitive coating, whereby, relative to said photosensitive coating, said image of said spatial light modulator moves across said photosensitive coating and a pixel in said photosensitive coating receives, in serial, doses of energy from multiple elements of said spatial light modulator; and blurring said image; wherein switching of said elements of said spatial light modulator is controlled 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 coating receive different, non-zero, total doses of energy. - View Dependent Claims (99, 100, 101, 102, 103, 104)
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Specification