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US5502654A
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Method for analyzing light intensity distribution in projection systems
Assignee: NEC Electronics Corp
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Filing: 1994-10-31
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Granted: 1996-03-26
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Expires: 2014-10-31
Abstract
Abstract A novel method for analyzing a light intensity distribution on a flat surface in a projection system wherein a pattern is projected by use of a light through a pupil on the flat surface. The pattern is analyzed into plural polygonal elements where a combination of the polygonal elements constitutes the pattern. Fourier transformations of vertexes of each of the polygonal elements except for the pattern are calculated for subsequent addition and subtraction of the Fourier transformations of all the polygonal elements to thereby obtain a Fourier transformation of the pattern. A product of the Fourier transformation of the pattern and a pupil function is calculated for the pupil. An invert Fourier transformation of the product is calculated to thereby obtain a light intensity distribution.
Inventors
- 👤 Koichi Sawahata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:06
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70058; G03F7/70483; G03F7/70591
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
127 words
A method for analyzing a light intensity distribution on a flat surface in a projection system wherein a pattern is projected by use of a light through a pupil on said flat surface, said method comprising the steps of: analyzing said pattern into plural polygonal elements where a combination of said polygonal elements constitutes said pattern; calculating Fourier transformations of vertexes of each of said polygonal elements except for said pattern for subsequent addition and subtraction of said Fourier transformations of all said polygonal elements to thereby obtain a Fourier transformation of said pattern; calculating a product of said Fourier transformation of said pattern and a pupil function for said pupil; and calculating an invert Fourier transformation of said product to thereby obtain a light intensity distribution.
Claim 2
Independent Claim
127 words
A method for analyzing a light intensity distribution on a flat surface in a projection system wherein a pattern is projected by use of a light through a pupil on said flat surface, said method comprising the steps of: analyzing said pattern into plural polygonal elements where a combination of said polygonal elements constitutes said pattern; calculating Fourier transformations of vertexes of each of said polygonal elements except for said pattern for subsequent addition and subtraction of said Fourier transformations of all said polygonal elements to thereby obtain a Fourier transformation of said pattern; calculating a product of said Fourier transformation of said pattern and a pupil function for said pupil; and calculating an invert Fourier transformation of said product to thereby obtain a light intensity distribution.
Claim 3
Dependent Claim
42 words
The method as claimed in claim 1, wherein said pattern is analyzed into a polygonal outside frame encompassing said pattern and plural kinds of polygonal elements so that a combination of said polygonal elements and said pattern constitutes said polygonal outside frame.
Claim 4
Dependent Claim
56 words
The method as claimed in claim 2, wherein said Fourier transformations of vertexes of each of said polygonal elements and said polygonal outside frame are calculated for subsequent subtraction of said Fourier transformations of all said polygonal elements from said Fourier transformation of said polygonal outside frame to thereby obtain a Fourier transformation of said pattern
Claim 5
Dependent Claim
18 words
The method as claimed in claim 2, wherein said polygonal outside frame is a rectangular encompassing said pattern.
Claim 6
Dependent Claim
27 words
The method as claimed in claim 2, wherein said polygonal elements comprises triangle elements and rectangular elements, each of said triangle and rectangle elements having various sizes.
Claim 7
Dependent Claim
15 words
The method as claimed in claim 5, wherein said triangle elements comprise right triangle elements.
Claim 8
Dependent Claim
21 words
The method as claimed in claim 1, wherein said pattern is analyzed into plural kinds of polygonal elements constituting said pattern.
Claim 9
Dependent Claim
42 words
The method as claimed in claim 7, wherein said Fourier transformations of vertexes of each of said polygonal elements are calculated for subsequent addition of said Fourier transformations of all said polygonal elements to thereby obtain a Fourier transformation of said pattern.
Claim 10
Dependent Claim
27 words
The method as claimed in claim 7, wherein said polygonal elements comprises triangle elements and rectangular elements, each of said triangle and rectangle elements having various sizes.
Claim 11
Dependent Claim
15 words
The method as claimed in claim 9, wherein said triangle elements comprise right triangle elements.
Claim 12
Dependent Claim
22 words
The method as claimed in claim 1, wherein said invert Fourier transformation is carried out by use of a fast Fourier transformation.
Claim 13
Dependent Claim
17 words
The method as claimed in claim 1, wherein said pattern comprises a pattern of a photo-resist mask.
Claim 14
Dependent Claim
26 words
The method as claimed in claim 1, wherein said pupil function is a step function expressing a transparent portion as "1" and an opaque portion "0".
Claim 15
Independent Claim
149 words
A method for analyzing a light intensity distribution on a flat surface in a projection system wherein a pattern is projected by use of a light through a pupil on said flat surface, said method comprising the steps of: analyzing said pattern into a polygonal outside frame and plural kinds of polygonal elements where a combination of said pattern and said polygonal elements constitutes said polygonal outside frame; calculating Fourier transformations of vertexes of each of said polygonal outside frame and all said polygonal elements except for said pattern; subtracting all said Fourier transformations of said polygonal elements from said Fourier transformation of said polygonal outside frame to thereby obtain a Fourier transformation of said pattern; calculating a product of said Fourier transformation of said pattern and a pupil function for said pupil; and calculating an invert Fourier transformation of said product to thereby obtain a light intensity distribution.
Claim 16
Independent Claim
149 words
A method for analyzing a light intensity distribution on a flat surface in a projection system wherein a pattern is projected by use of a light through a pupil on said flat surface, said method comprising the steps of: analyzing said pattern into a polygonal outside frame and plural kinds of polygonal elements where a combination of said pattern and said polygonal elements constitutes said polygonal outside frame; calculating Fourier transformations of vertexes of each of said polygonal outside frame and all said polygonal elements except for said pattern; subtracting all said Fourier transformations of said polygonal elements from said Fourier transformation of said polygonal outside frame to thereby obtain a Fourier transformation of said pattern; calculating a product of said Fourier transformation of said pattern and a pupil function for said pupil; and calculating an invert Fourier transformation of said product to thereby obtain a light intensity distribution.
Claim 17
Dependent Claim
22 words
The method as claimed in claim 14, wherein said invert Fourier transformation is carried out by use of a fast Fourier transformation.
Claim 18
Dependent Claim
18 words
The method as claimed in claim 14, wherein said polygonal outside frame is a rectangular encompassing said pattern.
Claim 19
Dependent Claim
27 words
The method as claimed in claim 14, wherein said polygonal elements comprises triangle elements and rectangular elements, each of said triangle and rectangle elements having various sizes.
Claim 20
Dependent Claim
15 words
The method as claimed in claim 17, wherein said triangle elements comprise right triangle elements.
Claim 21
Dependent Claim
17 words
The method as claimed in claim 14, wherein said pattern comprises a pattern of a photo-resist mask.
Claim 22
Dependent Claim
26 words
The method as claimed in claim 14, wherein said pupil function is a step function expressing a transparent portion as "1" and an opaque portion "0".
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-03-26 | 1999-09-25 | 2000-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-03-26 | 2003-09-25 | 2004-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-03-26 | 2007-09-25 | 2008-03-26 | $7700.00 | Window Closed / Lapsed |