Method for fine-line interferometric lithography
First Claim
1. In microelectronic processing, the method of producing a two-dimensional complex pattern on a photosensitive layer said pattern containing structures with dimensions in the extreme submicron range, comprising the steps of:
- a) exposing the photosensitive layer for a first time to two beams of coherent radiation which form an image of a first interference pattern on the surface of said layer;
b) exposing the photosensitive layer for at least one subsequent time to two beams of coherent radiation which form an image of at least one subsequent interference pattern, such that said subsequent interference pattern or patterns referenced to the photosensitive layer are each different from the first pattern;
c) isolating desired regions of said complex pattern with a further exposure of the photosensistive layer using any conventional lithography.
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Abstract
In microelectronic processing, the method of producing complex, two-dimensional patterns on a photosensitive layer with dimensions in the extreme submicron range. A photosensitive layer is first exposed to two beams of coherent radiation to form an image of a first interference pattern on the surface of the layer. The layer is subsequently exposed to one or more interference pattern(s) that differ from the first interference pattern in some way, such as by varying the incident angle of the beams, the optical intensity, the periodicity, rotational orientation, translational position, by using complex amplitude or phase masks in one or both of the coherent beams, or a combination of the above. Desired regions of the complex pattern thus produced are isolated with a further exposure of the photosensitive layer using any conventional lithography.
178 Citations
11 Claims
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1. In microelectronic processing, the method of producing a two-dimensional complex pattern on a photosensitive layer said pattern containing structures with dimensions in the extreme submicron range, comprising the steps of:
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a) exposing the photosensitive layer for a first time to two beams of coherent radiation which form an image of a first interference pattern on the surface of said layer; b) exposing the photosensitive layer for at least one subsequent time to two beams of coherent radiation which form an image of at least one subsequent interference pattern, such that said subsequent interference pattern or patterns referenced to the photosensitive layer are each different from the first pattern; c) isolating desired regions of said complex pattern with a further exposure of the photosensistive layer using any conventional lithography. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. In microelectronic processing, the method of producing a single isolated line of extreme submicron dimensions on a photosensitive layer comprising the steps of:
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a) exposing the photosensitive layer for a first time to two beams of coherent radiation such that an image of an interference pattern is formed on said layer; b) isolating a portion of a single line within said interference pattern by a second exposure of the photosensitive layer using conventional optical lithography.
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10. In microelectronic processing, a method of producing interdigitated structures on a photosensitive layer, comprising the steps of:
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a) exposing a defined area of the photosensitive layer with a first interference pattern, having a period p1, said defined area being bounded by two side edges approximately parallel to the lines of constant exposure dose and by top and bottom edges approximately perpendicular to the lines of constant exposure dose; b) exposing a second defined area containing the top edge of the first defined area with a second interference pattern of period p2 equal to twice p1 and with lines of constant exposure parallel to those of the first interference pattern, said second interference pattern being positioned relative to the first interference pattern such that every other unexposed region of the first exposure pattern within the second defined area is exposed; c) exposing a third defined area containing the bottom edge of the first defined area with a third interference pattern of period p2 equal to twice p1 and with lines of constant exposure parallel to those of the first interference pattern, said third interference pattern being positioned relative to the first and second interference patterns such that every other unexposed region of the first exposure pattern within the third defined area is exposed, said unexposed regions being connected to unexposed regions alternate to those exposed in step b. - View Dependent Claims (11)
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Specification