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US6686100B2
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Optical proximity correction method
Assignee: Microchip Technology Caldicot Ltd
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Filing: 2001-10-12
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Granted: 2004-02-03
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Expires: 2021-10-12
Abstract
Abstract A method of carrying out optical proximity correction in the design of a reticle for exposing a photoresist of a wafer in photolithography using a lens having a focal plane, the method including generating a dense-isolated offset focus/exposure matrix, containing dense-isolated offset values, being the difference between values of linewidth for dense and isolated lines, as a function of focal plane position, for each of a plurality of different exposures, selecting from among the contours of the dense-isolated offset focus/exposure matrix for each different exposure, the flattest contour, and carrying out optical proximity correction on the basis that the exposure will be the exposure corresponding to said flattest contour.
Inventors
- 👤 Brian Martin
- 👤 Christine Wallace
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 10:05
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70425; G03F7/70433; G03F7/70441; G03F1/00; G03F1/36; G03F7/70483; G03F7/7055; G03F7/70558; G03F7/70605; G03F7/70616; G03F7/70641
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
141 words
A method of carrying out optical proximity correction in the design of a reticle for exposing a photoresist on a substrate in photolithography using a lens having a focal plane, the method including the steps of: generating a dense-isolated offset focus/exposure matrix, containing dense-isolated offset values, being the difference between values for the linewidth of dense and isolated lines printed on said substrate, as a function of focal plane position, for each of a plurality of different exposures; selecting from among the contours of the dense-isolated offset focus/exposure matrix for each different exposure, the flattest contour, being the contour which is flattest in terms of variation of the dense-isolated offset over the range of focal plane positions of interest; and carrying out optical proximity correction on the basis that the exposure will be a selected exposure corresponding to said flattest contour.
Claim 2
Independent Claim
141 words
A method of carrying out optical proximity correction in the design of a reticle for exposing a photoresist on a substrate in photolithography using a lens having a focal plane, the method including the steps of: generating a dense-isolated offset focus/exposure matrix, containing dense-isolated offset values, being the difference between values for the linewidth of dense and isolated lines printed on said substrate, as a function of focal plane position, for each of a plurality of different exposures; selecting from among the contours of the dense-isolated offset focus/exposure matrix for each different exposure, the flattest contour, being the contour which is flattest in terms of variation of the dense-isolated offset over the range of focal plane positions of interest; and carrying out optical proximity correction on the basis that the exposure will be a selected exposure corresponding to said flattest contour.
Claim 3
Dependent Claim
79 words
A method as claimed in claim 1 , which further includes, prior to said generating step, the steps of: obtaining a first focus/exposure matrix, containing values for the linewidth of dense lines printed on said substrate as a function of focal plane position at said plurality of different exposures; obtaining a second focus/exposure matrix, containing values for the linewidth of isolated lines printed on said substrate as a function of focal plane position at said plurality of different exposures.
Claim 4
Dependent Claim
23 words
A method as claimed in claim 1 , wherein said dense lines have a line to space ratio of about 1 to 1.
Claim 5
Dependent Claim
23 words
A method as claimed in claim 1 , wherein said isolated lines have a line to space ratio of about 1 to 4.
Claim 6
Dependent Claim
27 words
A method as claimed in claim 1 , wherein an optical proximity correction program is used which makes use of rules generated by a rule generation program.
Claim 7
Dependent Claim
26 words
A method as claimed in claim 1 , wherein a lithography simulation program is used to simulate the behaviour of the photoresist at said selected exposure.
Claim 8
Dependent Claim
23 words
A method as claimed in claim 5 , wherein the results of said lithography simulation program are used by said rule generation program.
Claim 9
Dependent Claim
18 words
A method as claimed in claim 1 , wherein said obtaining steps are carried out by computer simulation.
Claim 10
Dependent Claim
18 words
A method as claimed in claim 1 , wherein said selecting step is carried out by a person.
Claim 11
Dependent Claim
10 words
A reticle produced by the method of claim 1 .
References Cited (Backward Citations)
US5657235A
Cited
US5862058A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2007-02-02 | 2007-08-04 | 2008-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2011-02-02 | 2011-08-04 | 2012-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2015-02-02 | 2015-08-04 | 2016-02-03 | $7700.00 | Window Closed / Lapsed |