US6289499B1
Expired / Lapsed
US
⏱️ 0.0 years remaining
Proximity correction software for wafer lithography
Assignee: Synopsys Inc
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Filing: 2000-01-07
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Granted: 2001-09-11
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Expires: 2020-01-07
Abstract
Abstract A system for computing a pattern function for a polygonal pattern having a finite number of predetermined face angles. One method includes the steps of decomposing the polygon into a set of flashes, computing the pattern function by summing together all flashes evaluated at a point (x,y), and the pattern function returning a 1 if point (x,y) is inside a polygon and otherwise will return a 0. Another method for computing a two-dimensional convolution value for any point (x,y) on a polygonal pattern includes the steps of identifying a set of half-plane basis functions corresponding to each face angle of the polygonal pattern, convolving each half-plane basis function with a convolution kernel using integration to find convolved flash (cflash) x,y values, storing the cflash (x,y) values to a two-dimensional look-up table, decomposing the polygonal pattern into a set of flashes where each of the flashes is an instance of the half-plane basis functions, and computing a convolution value for point (x,y) by looking-up a corresponding cflash x,y value for each flash in the table and summing together the corresponding cflash x,y values. The present invention may be used in a method for determining correction steps to which a design layout is to be subjected during wafer proximity correction.
Inventors
- 👤 Michael L. Rieger
- 👤 John P. Stirniman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 04:11
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/36; G03F7/00; G03F7/70; G03F7/70425; G03F7/70433; G03F7/70441
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
137 words
A method implemented in a computer for computing a convolution value for a point x, y on a pattern of a plurality of polygons (hereinafter “polygonal pattern”), each of said polygons having only face angles selected from a set of predetermined face angles, said method comprising: identifying a set of half-plane basis functions, each half-plane basis function corresponding to one of said predetermined face angles; convolving said half-plane basis functions with a convolution kernel to obtain convolved values; saving said convolved values in memory; decomposing said polygonal pattern into a set of flashes wherein each flash is an instance of one of said half-plane basis functions; for point x, y, retrieving a corresponding convolved value for each flash in the set, and summing together at least a subset of corresponding convolved values to obtain said convolution value.
Claim 2
Independent Claim
137 words
A method implemented in a computer for computing a convolution value for a point x, y on a pattern of a plurality of polygons (hereinafter “polygonal pattern”), each of said polygons having only face angles selected from a set of predetermined face angles, said method comprising: identifying a set of half-plane basis functions, each half-plane basis function corresponding to one of said predetermined face angles; convolving said half-plane basis functions with a convolution kernel to obtain convolved values; saving said convolved values in memory; decomposing said polygonal pattern into a set of flashes wherein each flash is an instance of one of said half-plane basis functions; for point x, y, retrieving a corresponding convolved value for each flash in the set, and summing together at least a subset of corresponding convolved values to obtain said convolution value.
Claim 3
Dependent Claim
25 words
The method of claim 1 wherein: said convolved values are stored in a two-dimensional table using x and y coordinates as indices into said table.
Claim 4
Independent Claim
105 words
A method implemented in a computer for computing a convolution value for a point x, y on a polygonal pattern, said polygonal pattern including a plurality of vertices and angles, said method comprising: convolving a plurality of linear functions with a convolution kernel to obtain convolved values, and saving said convolved values in memory; and for point x, y, retrieving one of the saved convolved values for each instance of each angle at each vertex in said polygonal pattern, said angle being one of a set of discrete angles; and for point x, y, summing together the retrieved convolved values to obtain said convolution value.
Claim 5
Independent Claim
105 words
A method implemented in a computer for computing a convolution value for a point x, y on a polygonal pattern, said polygonal pattern including a plurality of vertices and angles, said method comprising: convolving a plurality of linear functions with a convolution kernel to obtain convolved values, and saving said convolved values in memory; and for point x, y, retrieving one of the saved convolved values for each instance of each angle at each vertex in said polygonal pattern, said angle being one of a set of discrete angles; and for point x, y, summing together the retrieved convolved values to obtain said convolution value.
Claim 6
Dependent Claim
19 words
The method of claim 3 further comprising: identifying one of said linear functions for each angle in said set.
Claim 7
Dependent Claim
14 words
The method of claim 3 wherein: each linear function is a half-plane basis function.
Claim 8
Dependent Claim
15 words
The method of claim 3 further comprising: using said convolution value to obtain a simulation.
Claim 9
Dependent Claim
21 words
The method of claim 6 further comprising: using said simulation to subject to proximity correction a layout having said polygonal pattern.
Claim 10
Dependent Claim
25 words
The method of claim 3 further comprising: using said convolution value to subject an image having said polygonal pattern to the effect of a lens.
Claim 11
Dependent Claim
26 words
The method of claim 3 wherein: said convolution kernel is derived from at least one measurement of a dimension of a feature of a test wafer.
Claim 12
Dependent Claim
20 words
The method of claim 3 further comprising: identifying a plurality of bounded regions containing all polygons of said polygonal pattern.
Claim 13
Dependent Claim
68 words
The method of claim 10 further comprising: extending at least one bounded region by a predetermined extent around said region to defined an operating space; dividing the operating space into a plurality of bands; during said act of saving, identifying bands with which each convolved value is to be associated; and during said act of retrieving, using convolved values associated with a band containing the point x, y.
Claim 14
Independent Claim
101 words
A method implemented in a computer for identifying proximity correction on an original design layout, said method comprising: convolving the original design layout with a plurality of convolution kernels to obtain a simulation of an original image to be formed on a wafer by use of the original design layout; and identifying an adjustment in at least a portion of the original design layout using the simulation so that a corrected layout obtained therefrom forms a corrected image that differs from the original design layout by an amount smaller than a difference between the original image and the original design layout.
Claim 15
Independent Claim
101 words
A method implemented in a computer for identifying proximity correction on an original design layout, said method comprising: convolving the original design layout with a plurality of convolution kernels to obtain a simulation of an original image to be formed on a wafer by use of the original design layout; and identifying an adjustment in at least a portion of the original design layout using the simulation so that a corrected layout obtained therefrom forms a corrected image that differs from the original design layout by an amount smaller than a difference between the original image and the original design layout.
Claim 16
Dependent Claim
15 words
The method of claim 12 further comprising: iteratively performing the acts of convolving and identifying.
Claim 17
Dependent Claim
21 words
The method of claim 12 further comprising, prior to the convolving: identifying at least a portion of a convolution kernel empirically.
Claim 18
Dependent Claim
40 words
The method of claim 12 wherein the act of convolving includes: retrieving a previously saved convolved value for each instance of a face angle in a polygonal pattern in the original design layout, and summing together the retrieved convolved values.
Claim 19
Dependent Claim
14 words
The method of claim 12 further comprising: creating a corrected mask using said adjustment.
Claim 20
Dependent Claim
22 words
The method of claim 16 further comprising: using said corrected mask in wafer lithography to produce a wafer having the corrected image.
Claim 21
Independent Claim
110 words
A method implemented in a computer for identifying an original design layout to correct for distortions during a wafer lithography process, said method comprising: forming a model of said wafer lithography process using measurements of dimensions of features in an uncorrected test wafer; and identifying an adjustment in at least a portion of the original design layout using the model so that a corrected layout obtained therefrom forms a corrected image that differs from the original design layout by an amount smaller than a difference between an original image and the original design layout, the original image being obtained by performing the wafer lithography process on the original design layout.
Claim 22
Independent Claim
110 words
A method implemented in a computer for identifying an original design layout to correct for distortions during a wafer lithography process, said method comprising: forming a model of said wafer lithography process using measurements of dimensions of features in an uncorrected test wafer; and identifying an adjustment in at least a portion of the original design layout using the model so that a corrected layout obtained therefrom forms a corrected image that differs from the original design layout by an amount smaller than a difference between an original image and the original design layout, the original image being obtained by performing the wafer lithography process on the original design layout.
Claim 23
Dependent Claim
32 words
The method of claim 18 further comprising: prior to the identifying, forming a correction recipe using the model; and using the correction recipe to subject the original design layout to proximity correction.
Claim 24
Dependent Claim
32 words
The method of claim 18 further comprising: creating a corrected mask using said adjustment; and using said corrected mask in the wafer lithography process to produce a wafer having the corrected image.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-09-10 | 2005-03-12 | 2005-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-09-10 | 2009-03-12 | 2009-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-09-10 | 2013-03-12 | 2013-09-11 | $7700.00 | Window Closed / Lapsed |