METHOD OF OPERATION FOR SLM-BASED OPTICAL LITHOGRAPHY TOOL
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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
104 Claims
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1-79. -79. (canceled)
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80. A method of operating a spatial light modulator based optical lithography tool for patterning a substrate, comprising:
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defining an area array of pixels on said substrate surface, the size and configuration of said pixels corresponding to the projected spacing and configuration of individually switchable elements in said spatial light modulator; assigning a dose value to each pixel on said substrate, said dose being computed from a feature pattern in a design data file; decompressing said dose values for each pixel on said substrate into a sequence of values representing states for each element of said spatial light modulator for each clock cycle, said elements having at least two states, wherein a first state allows light to reach said substrate and a second state stops light from reaching said substrate; loading said element state values into a spatial light modulator memory; illuminating said spatial light modulator; projecting an image of said spatial light modulator on said substrate, said projection being implemented by projection optics situated between said spatial light modulator and said substrate; once every clock cycle, switching said elements of said spatial light modulator according to said values in said spatial light modulator memory; and during each clock cycle, displacing said substrate and said projected image relative to each other by a distance equal to said spacing between said pixels; wherein a pixel on said substrate receives, in serial, doses of energy from multiple elements of said spatial light modulator. - View Dependent Claims (81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104)
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Specification