EP0608657A1
Expired / Lapsed
EP
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Apparatus and method for preparing shape data for proximity correction
Assignee: International Business Machines Corp
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Filing: 1993-12-15
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Granted: —
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Expires: 2013-12-15
Abstract
Abstract In electron beam lithography, an apparatus and method decompose rectangles at the exterior of a desired electron beam exposure pattern into portions having a substantially constant environment. This process also includes sorting of rectangles into bands in order of addresses of the rectangles and the assignment of labels or tags to the resulting rectangles indicating the edge(s) of the rectangle at which cuts were made to form the rectangle. When these rectangles are further decomposed by increment cutting and processes to receive exposure doses corrected by mutual proximity effects, including recombination of rectangles having the same assigned exposure dose, improved location of cut boundaries is achieved. Overexposure and resultant blooming of the pattern is prevented and exposure dose is assigned with higher accuracy since any averaging of exposure dose will be over a region having a substantially constant environment of neighboring shapes. Additionally, by ordering of the shapes, and cutting (with recombination) in plural steps, data carried forward in subsequent processing is reduced and accumulation of exposure correction information is facilitated.
Inventors
- 👤 Virginia Marie Chung
- 👤 Joseph Blaise Frei
- 👤 James Edward Stuart
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 12:03
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/30; H01J37/302; H01J37/3023; H01J37/3026
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
123 words
A method of partitioning shapes included in an exposure pattern, characterized in that it comprises the steps of: dividing said exposure pattern into shapes including interior and exterior rectangles, said exterior rectangles having a predetermined maximum width and arbitrary length, subdividing at least one of said exterior rectangles at a location along its length having the same horizontal or vertical address as the boundary of a shape in said exposure pattern which is within a scattering distance of said at least one of said exterior rectangles, and storing a description of each rectangle resulting from said subdividing step, said description including at least an address corresponding to said location, said descriptions forming an ordered list in accordance with at least one said address.
Claim 2
Dependent Claim
26 words
A method as recited in claim 1, wherein said exposure pattern is an electron beam exposure pattern to be formed by an electron beam lithography process.
Claim 3
Dependent Claim
37 words
A method as recited in claim 1 or 2, wherein said description includes data representing a separation distance between said at least one of said exterior rectangles and said boundary of said shape within said scattering distance.
Claim 4
Dependent Claim
29 words
A method as recited in claim 3, including the further step of combining at least two rectangles which are adjacent and equally separated from said boundary of said shape.
Claim 5
Dependent Claim
50 words
A method as recited in claim 1, further including the steps of increment cutting, in accordance with said ordered list, of rectangles for which descriptions have been stored by said storing step, and maintaining a description of types of cuts made by said increment cutting step in an ordered list.
Claim 6
Dependent Claim
94 words
A method as recited in claim 5, including the further steps of computing a mutual exposure correction for each shape resulting respectively from said increment cutting step or said subdividing step based upon a separation distance between each said shape resulting from said increment cutting step or said subdividing step and every other shape resulting from said increment cutting step or subdividing step which is within a scattering distance of each said shape, and accumulating said mutual exposure correction for each said shape resulting respectively from said increment cutting step or said subdividing step.
Claim 7
Dependent Claim
58 words
A method as recited in claim 6, wherein said step of computing a mutual exposure correction computes a correction for each said shape and each said other shape having an address within said exposure pattern which is subsequent to an address of said shape. accumulating said mutual exposure correction for each said shape resulting from said subdividing step.
Claim 8
Dependent Claim
20 words
A method as recited in claim 1, wherein said subdividing step is performed in address order within said exposure pattern.
Claim 9
Dependent Claim
43 words
A method as recited in claim 1, including the further step of dividing said exposure pattern into bands, each said band having a width which is an integral multiple of a distance between consecutive addresses in one coordinate direction of said exposure pattern.
Claim 10
Dependent Claim
17 words
A method as recited in claim 9, wherein said integral multiple is an integral power of two.
Claim 11
Dependent Claim
26 words
A method as recited in claim 9 or 10, wherein said subdividing step is performed in address order within one said band of said exposure pattern.
Claim 12
Dependent Claim
72 words
A method as recited in claim 6, including the further steps of computing an exposure dose for each said shape from said mutual exposure corrections accumulated by said accumulating step, comparing said exposure dose of each said shape with an exposure dose of an abutting shape, and combining said shape and said abutting shape if said exposure dose of said shape and said exposure dose of said abutting shape are approximately equal.
Claim 13
Dependent Claim
27 words
A method as recited in claim 12, wherein said abutting shape is determined in accordance with said ordered list of cuts made during said increment cutting step.
Claim 14
Dependent Claim
26 words
A method as recited in claim 12, wherein said abutting shape is determined in accordance with said ordered list of cuts made during said subdividing step.
Claim 15
Dependent Claim
22 words
A method as recited in claim 6, wherein said step of computing a mutual exposure correction includes approximation with a limiting function.
Claim 16
Independent Claim
126 words
An apparatus for partitioning shapes included in an exposure pattern, characterized in that it comprises: means for dividing said exposure pattern into shapes including interior and exterior rectangles, said exterior rectangles having a predetermined maximum width and arbitrary length, means for subdividing at least one of said exterior rectangles at a location along its length having the same horizontal or vertical address as the boundary of a shape in said exposure pattern which is within a scattering distance of said at least one of said exterior rectangles, and means for storing a description of each rectangle resulting from said subdividing step, said description including at least an address corresponding to said location, said descriptions forming an ordered list in accordance with at least one said address.
Claim 17
Dependent Claim
55 words
The apparatus as recited in claim 16, wherein said exposure pattern is an electron beam exposure pattern to be formed by an electron beam lithography process, and wherein said description includes data representing a separation distance between said at least one of said exterior rectangles and said boundary of said shape within said scattering distance.
Claim 18
Dependent Claim
135 words
The apparatus as recited in claim 16, further including means for increment cutting, in accordance with said ordered list, of rectangles for which descriptions have been stored by said storing step, and maintaining a description of types of cuts made by said increment cutting step in an ordered list, means for computing a mutual exposure correction for each shape resulting respectively from said increment cutting step or said subdividing step based upon a separation distance between each said shape resulting from said increment cutting step or said subdividing step and every other shape resulting from said increment cutting step or subdividing step which is within a scattering distance of each said shape, and means for accumulating said mutual exposure correction for each said shape resulting respectively from said increment cutting step or said subdividing step.
References Cited (Backward Citations)
US5086398A
Cited
EP0496159A2
Cited
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