Patent US7588868B2 successfully refreshed from Google Patents.
US7588868B2
Expired / Lapsed
US
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Method and system for reducing the impact of across-wafer variations on critical dimension measurements
Assignee: Cadence Design Systems Inc
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Filing: 2004-10-22
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Granted: 2009-09-15
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Expires: 2024-10-22
Abstract
Abstract First and second exposures of a mask onto a wafer are performed such that the exposure field of the second exposure partially overlaps the exposure field of the first exposure. A characteristic of a set of features is determined, and a value of a parameter of an optical proximity correction model is determined. An alignment feature can be used to align a measurement tool. In yet another embodiment, pupil intensity distribution of an imaging system is measured by exposing an image field of a radiation detector with a bright feature, positioning the detector at a distance away from the image plane, and exposing the image field of the detector with a bright feature, resulting in a cumulative exposure of the image field of the detector from the two exposures. A characteristic of a spatial pattern in the cumulative exposure of the image field of the detector is then determined.
Inventors
- 👤 Franz X. Zach
- 👤 Abdurrahman Sezginer
- 👤 Gokhan Percin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:52
CPC Classifications
G; G03; G03B; G03B27/00; G03B27/72; G03F; G03F7/00; G03F7/70; G03F7/70425; G03F7/70433; G03F7/70441; G03F7/70483; G03F7/7055; G03F7/70558; G03F7/70605; G03F7/70616; G03F7/70625; G03F7/70641
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
105 words
A method for determining a value of a parameter of an optical proximity correction model, the method comprising: (a) performing a first exposure of a mask onto a wafer, wherein the mask comprises a set of features; (b) performing a second exposure of the mask onto the wafer, wherein an exposure field of the second exposure partially overlaps an exposure field of the first exposure; (c) determining a characteristic of the set of features exposed onto the wafer by the first and second exposures; and (d) determining a value of a parameter of an optical proximity correction model based on the characteristic determined in (c).
Claim 2
Independent Claim
105 words
A method for determining a value of a parameter of an optical proximity correction model, the method comprising: (a) performing a first exposure of a mask onto a wafer, wherein the mask comprises a set of features; (b) performing a second exposure of the mask onto the wafer, wherein an exposure field of the second exposure partially overlaps an exposure field of the first exposure; (c) determining a characteristic of the set of features exposed onto the wafer by the first and second exposures; and (d) determining a value of a parameter of an optical proximity correction model based on the characteristic determined in (c).
Claim 3
Dependent Claim
60 words
The method of claim 1 , wherein the mask comprises a frame around the set of features, wherein, in the first exposure, the frame prevents exposure of an area on the wafer surrounding the set of features, and wherein, in the second exposure, the frame prevents light from reaching areas on the wafer that were exposed in the first exposure.
Claim 4
Dependent Claim
52 words
The method of claim 1 , wherein (d) comprises determining the value of a parameter through a comparison of the characteristic determined in (c) with a characteristic simulated from the optical proximity correction model based on the set of features on the mask and exposure conditions of the first and second exposures.
Claim 5
Dependent Claim
20 words
The method of claim 1 , wherein the optical proximity correction model comprises a model of a mask manufacturing process.
Claim 6
Dependent Claim
20 words
The method of claim 1 , wherein the optical proximity correction model comprises a model of an optical exposure process.
Claim 7
Dependent Claim
18 words
The method of claim 1 , wherein the optical proximity correction model comprises a model of resist processing.
Claim 8
Dependent Claim
24 words
The method of claim 6 , wherein the set of features comprises a line, and wherein (c) comprises measuring a width of the line.
Claim 9
Dependent Claim
26 words
The method of claim 6 , wherein the set of features comprises a space pattern, and wherein (c) comprises measuring a width of the space pattern.
Claim 10
Dependent Claim
19 words
The method of claim 1 , wherein the optical proximity correction model comprises a model of an etch process.
Claim 11
Dependent Claim
40 words
The method of claim 1 , wherein the optical proximity correction model is operative to predict a printed wafer image based on a given layout using a description of image transformation of at least one step of a patterning process.
Claim 12
Dependent Claim
38 words
The method of claim 1 , wherein the mask further comprises an alignment feature, and wherein the method further comprises aligning a measurement tool using alignment 20 features exposed onto the wafer by the first and second exposures.
Claim 13
Dependent Claim
19 words
The method of claim 1 , wherein the first and second exposures are performed using the same exposure conditions.
Claim 14
Dependent Claim
36 words
The method of claim 12 , wherein the same exposure condition is used in both the first and second exposures, and the method further comprises reducing measurement noise on one of the characteristics determined in (c).
Claim 15
Dependent Claim
21 words
The method of claim 1 , wherein the first and second exposures are performed using at least one different exposure condition.
Claim 16
Dependent Claim
25 words
The method of claim 14 , wherein the at least one different exposure condition comprises at least one of the following: dose, focus, and illumination.
Claim 17
Dependent Claim
67 words
The method of claim 1 further comprising performing at least one additional exposure of the mask onto the wafer, wherein an exposure field of each of the at least one additional exposure partially overlaps an exposure field of a previous exposure, and wherein (c) comprises determining a characteristic of the set of features exposed onto the wafer by the first, second, and at least one additional exposures.
Claim 18
Dependent Claim
49 words
The method of claim 16 , wherein the same exposure condition is used in at least some of the first, second, and at least one additional exposures, and the method further comprises reducing measurement noise on a characteristics determined in (c) using the exposures with the same exposure condition.
Claim 19
Dependent Claim
28 words
The method of claim 16 , wherein the first, second, and at least one additional exposures are performed using at least one different exposure condition for each exposure.
Claim 20
Dependent Claim
25 words
The method of claim 18 , wherein the at least one different exposure condition comprises at least one of the following: dose, focus, and illumination.
Claim 21
Dependent Claim
23 words
The method of claim 18 further comprising determining a dependency of the set of features and the at least one different exposure condition.
Claim 22
Dependent Claim
12 words
The method of claim 1 , wherein the characteristic comprises critical dimension.
Claim 23
Dependent Claim
15 words
The method of claim 1 , wherein the set of features comprises a bright feature.
Claim 24
Dependent Claim
19 words
The method of claim 1 , wherein the set of features comprises a combination of bright and dark features.
Claim 25
Dependent Claim
53 words
The method of claim 1 , wherein the set of features are placed in multiple field locations within the exposure field of the first exposure, wherein (c) is performed in a field-dependent manner, wherein the optical proximity correction model allows for position-dependent parameters, and wherein (d) is performed in a field-position dependent manner.
Claim 26
Independent Claim
123 words
A method for determining a characteristic of a set of features exposed onto a wafer, the method comprising: (a) performing a first exposure of a mask at a first location on a wafer, wherein the mask comprises patterns for the set of features and an alignment feature; (b) performing a second exposure of the mask onto the wafer, wherein the second exposure patterns the set of features at a second location on the wafer; (c) aligning a measurement tool using the alignment features exposed onto the wafer by the first and second exposures and (d) using the measurement tool to measure dimensional characteristics of the set of features patterned at the first location on the wafer and the second location on the wafer.
Claim 27
Independent Claim
123 words
A method for determining a characteristic of a set of features exposed onto a wafer, the method comprising: (a) performing a first exposure of a mask at a first location on a wafer, wherein the mask comprises patterns for the set of features and an alignment feature; (b) performing a second exposure of the mask onto the wafer, wherein the second exposure patterns the set of features at a second location on the wafer; (c) aligning a measurement tool using the alignment features exposed onto the wafer by the first and second exposures and (d) using the measurement tool to measure dimensional characteristics of the set of features patterned at the first location on the wafer and the second location on the wafer.
Claim 28
Dependent Claim
68 words
The method of claim 25 , wherein the mask comprises a frame around the set of features and the alignment feature, wherein, in the first exposure, the frame prevents exposure of an area on the wafer surrounding the set of features and the alignment feature, and wherein, in the second exposure, the frame prevents light from reaching areas on the wafer that were exposed in the first exposure.
Claim 29
Dependent Claim
67 words
The method of claim 25 further comprising performing at least one additional exposure of the mask onto the wafer, wherein an exposure field of each of the at least one additional exposure partially overlaps an exposure field of a previous exposure, and wherein (c) comprises aligning a measurement tool using the alignment features exposed onto the wafer by the first, second, and at least one additional exposures.
Claim 30
Dependent Claim
51 words
The method of claim 27 , wherein the same exposure condition is used in at least some of the first, second, and at least one additional exposures, and wherein the method further comprises reducing measurement noise using the dimensional characteristic determined in (d) on the exposures with the same exposure condition.
Claim 31
Dependent Claim
28 words
The method of claim 27 , wherein the first, second, and at least one additional exposures are performed using at least one different exposure condition for each exposure.
Claim 32
Dependent Claim
25 words
The method of claim 29 , wherein the at least one different exposure condition comprises at least one of the following: dose, focus, and illumination.
Claim 33
Dependent Claim
23 words
The method of claim 29 further comprising determining a dependency of the set of features and the at least one different exposure condition.
Claim 34
Dependent Claim
27 words
The method of claim 25 further comprising determining a value of a parameter of an optical proximity correction model based on the dimensional characteristics measured in (d).
Claim 35
Dependent Claim
20 words
The method of claim 32 , wherein the optical proximity correction model comprises a model of a mask manufacturing process.
Claim 36
Dependent Claim
20 words
The method of claim 32 , wherein the optical proximity correction model comprises a model of an optical exposure process.
Claim 37
Dependent Claim
18 words
The method of claim 32 , wherein the optical proximity correction model comprises a model of resist processing.
Claim 38
Dependent Claim
19 words
The method of claim 32 , wherein the optical proximity correction model comprises a model of an etch process.
Claim 39
Dependent Claim
19 words
The method of claim 25 , wherein the first and second exposures are performed using the same exposure conditions.
Claim 40
Dependent Claim
21 words
The method of claim 25 , wherein the first and second exposures are performed using at least one different exposure condition.
Claim 41
Dependent Claim
25 words
The method of claim 38 , wherein the at least one different exposure condition comprises at least one of the following: dose, focus, and illumination.
Claim 42
Dependent Claim
13 words
The method of claim 25 , wherein the dimensional characteristic comprises critical dimension.
Claim 43
Dependent Claim
15 words
The method of claim 25 , wherein the set of features comprises a bright feature.
Claim 44
Dependent Claim
19 words
The method of claim 25 , wherein the set of features comprises a combination of bright and dark features.
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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) | 2012-09-14 | 2013-03-16 | 2013-09-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2016-09-14 | 2017-03-16 | 2017-09-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2020-09-14 | 2021-03-16 | 2021-09-15 | $7700.00 | Window Closed / Lapsed |