Microlens scanner for microlithography and wide-field confocal microscopy
First Claim
1. A printing system comprising:
- an optical projection system having an object plane, an image plane which is conjugate to the object plane, and a limiting aperture stop which is referred to as the projection aperture;
a planar array of microlenses having respective apertures defining a microlens aperture array, wherein the aperture array is positioned at the projection system'"'"'s image plane, and wherein the microlenses have respective focal points which are conjugate to the projection aperture and which define a focal point array;
a scanning mechanism which establishes relative motion between the the microlens array and a printing surface proximate the focal point array, wherein the paths traversed by the focal points relative to the printing surface comprise a set of closely-spaced raster lines;
an image source comprising an array of light-modulating image source elements, wherein the image source is positioned at the projection system'"'"'s object plane, and wherein the projection system images each image source element onto a corresponding microlens aperture and the image source element thus controls the light level over a microspot on the printing surface, proximate the corresponding microlens focal point; and
an image modulation mechanism that controls the image source as the printing surface is scanned, whereby, when a photosensitive material is positioned in the printing surface, a synthesized, high-resolution raster image is recorded on the photosensitive material.
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Abstract
A microscopy and/or lithography system uses a comparatively low-resolution image projection system, which has a very small numerical aperture but large image field, in conjunction with a microlens array comprising miniature lens elements, each of which has a large numerical aperture but very small field. The projection system contains a small aperture stop which is imaged by the microlenses onto an array of diffraction-limited microspots on the microscope sample or printing surface at the microlens focal point positions, and the surface is scanned to build up a complete raster image from the focal point array. The system design thus circumvents the tradeoff between image resolution and field size which is the source of much of the complexity and expense of conventional wide-field, high-NA microscopy and microlithography systems. The system makes possible flat field, distortion-free imaging, with accurate overlay, focus, and warp compensation, over very large image fields (larger than the practical limits of conventional imaging means). In one embodiment it would use a Digital Micromirror Device as the image source, potentially eliminating the need for photomasks in semiconductor manufacture.
818 Citations
35 Claims
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1. A printing system comprising:
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an optical projection system having an object plane, an image plane which is conjugate to the object plane, and a limiting aperture stop which is referred to as the projection aperture; a planar array of microlenses having respective apertures defining a microlens aperture array, wherein the aperture array is positioned at the projection system'"'"'s image plane, and wherein the microlenses have respective focal points which are conjugate to the projection aperture and which define a focal point array; a scanning mechanism which establishes relative motion between the the microlens array and a printing surface proximate the focal point array, wherein the paths traversed by the focal points relative to the printing surface comprise a set of closely-spaced raster lines; an image source comprising an array of light-modulating image source elements, wherein the image source is positioned at the projection system'"'"'s object plane, and wherein the projection system images each image source element onto a corresponding microlens aperture and the image source element thus controls the light level over a microspot on the printing surface, proximate the corresponding microlens focal point; and an image modulation mechanism that controls the image source as the printing surface is scanned, whereby, when a photosensitive material is positioned in the printing surface, a synthesized, high-resolution raster image is recorded on the photosensitive material. - 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, 31, 32, 33, 34, 35)
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Specification