US6873720B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
System and method of providing mask defect printability analysis
Assignee: Synopsys Inc
•
Filing: 2001-03-20
•
Granted: 2005-03-29
•
Expires: 2021-03-20
Abstract
Abstract A simulated wafer image of a physical mask and a defect-free reference image are used to generate a severity score for each defect, thereby giving a customer meaningful information to accurately assess the consequences of using a mask or repairing that mask. The defect severity score is calculated based on a number of factors relating to the changes in critical dimensions of the neighbor features to the defect. A common process window can also be used to provide objective information regarding defect printability. Certain other aspects of the mask relating to mask quality, such as line edge roughness and contact corner rounding, can also be quantified by using the simulated wafer image of the physical mask.
Inventors
- 👤 Lynn Cai
- 👤 Linard Karklin
- 👤 Linyong Pang
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:03
CPC Classifications
G; G03; G03F; G03F1/00; G03F1/68; G03F1/82; G03F1/84; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/956; G01N21/95607; G03F7/00; G03F7/70; G03F7/70425; G03F7/70433; G03F7/70483; G03F7/70491; G03F7/705; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24802
Claims Analysis
Total Claims: 66
Claim 1
Independent Claim
97 words
A method of providing printability analysis for a defect on a physical mask, the method comprising: generating a simulated wafer image of the physical mask; generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask; identifying a first feature proximate to the defect on the simulated wafer image of the physical mask; identifying a second feature on the simulated wafer image of the reference mask, the second feature corresponding to the first feature; and computing critical dimension deviations including the first and second features to provide the printability analysis.
Claim 2
Independent Claim
97 words
A method of providing printability analysis for a defect on a physical mask, the method comprising: generating a simulated wafer image of the physical mask; generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask; identifying a first feature proximate to the defect on the simulated wafer image of the physical mask; identifying a second feature on the simulated wafer image of the reference mask, the second feature corresponding to the first feature; and computing critical dimension deviations including the first and second features to provide the printability analysis.
Claim 3
Dependent Claim
27 words
The method of claim 1 , wherein computing includes determining a first critical dimension of the first feature and a second critical dimension of the second feature.
Claim 4
Dependent Claim
21 words
The method of claim 2 , wherein computing includes calculating a relative critical dimension deviation for the first and second features.
Claim 5
Dependent Claim
34 words
The method of claim 3 , wherein calculating the relative critical dimension deviation includes subtracting the second critical dimension from the first critical dimension, and dividing a resulting value by the second critical dimension.
Claim 6
Dependent Claim
71 words
The method of claim 3 , further including: identifying a first plurality of features proximate to the defect on the simulated wafer image of the physical mask; identifying a second plurality of features on the simulated wafer image of the reference mask, the second plurality of features corresponding to the first plurality of features; and calculating a plurality of relative critical dimension deviations for the first and second plurality of features.
Claim 7
Dependent Claim
26 words
The method of claim 5 , further including determining the largest of the plurality of relative critical dimension deviations, thereby providing a maximum critical dimension deviation.
Claim 8
Independent Claim
142 words
A method of providing printability analysis for a defect on a physical mask, the method comprising: generating a simulated wafer image of the physical mask; generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask; identifying a first feature proximate to the defect on the simulated wafer image of the physical mask; identifying a second feature on the simulated wafer image of the reference mask, the second feature corresponding to the first feature; computing critical dimension deviations including the first and second features to provide the printability analysis; identifying, a third defect-free feature on the simulated wafer image of the physical mask; identifying a fourth feature on the simulated wafer image of the reference mask, the fourth feature corresponding to the third feature; and computing critical dimension deviations including the third and fourth features.
Claim 9
Independent Claim
142 words
A method of providing printability analysis for a defect on a physical mask, the method comprising: generating a simulated wafer image of the physical mask; generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask; identifying a first feature proximate to the defect on the simulated wafer image of the physical mask; identifying a second feature on the simulated wafer image of the reference mask, the second feature corresponding to the first feature; computing critical dimension deviations including the first and second features to provide the printability analysis; identifying, a third defect-free feature on the simulated wafer image of the physical mask; identifying a fourth feature on the simulated wafer image of the reference mask, the fourth feature corresponding to the third feature; and computing critical dimension deviations including the third and fourth features.
Claim 10
Dependent Claim
32 words
The method of claim 7 , wherein computing the third and fourth features includes determining a first critical dimension of the third feature and a second critical dimension of the fourth feature.
Claim 11
Dependent Claim
20 words
The method of claim 8 , wherein computing includes calculating a critical dimension deviation for the first and second features.
Claim 12
Dependent Claim
33 words
The method of claim 9 , wherein calculating the critical dimension deviation includes subtracting the first critical dimension from the second critical dimension, and dividing a resulting value by the second critical dimension.
Claim 13
Dependent Claim
37 words
The method of claim 9 , further including calculating the critical dimension deviation for N defect-free features on the simulated wafer image of the physical mask, wherein N is an integer equal to or greater than two.
Claim 14
Dependent Claim
32 words
The method of claim 11 , wherein the critical dimension deviation for each defect-free feature is added, and a resulting value is divided by N, thereby providing an average critical dimension deviation.
Claim 15
Independent Claim
111 words
A method of providing printability analysis for a defect on a physical mask, the method comprising: generating a simulated wafer image of the physical mask; generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask; computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks; computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks; and using the average critical dimension deviation and the maximum critical dimension deviation to provide the printability analysis.
Claim 16
Independent Claim
111 words
A method of providing printability analysis for a defect on a physical mask, the method comprising: generating a simulated wafer image of the physical mask; generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask; computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks; computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks; and using the average critical dimension deviation and the maximum critical dimension deviation to provide the printability analysis.
Claim 17
Dependent Claim
19 words
The method of claim 13 , further including determining a defect severity score based on the step of using.
Claim 18
Dependent Claim
15 words
The method of claim 13 , further including determining a tolerance for critical dimension changes.
Claim 19
Dependent Claim
21 words
The method of claim 15 , wherein using includes using the tolerance for critical dimension changes to provide the printability analysis.
Claim 20
Dependent Claim
15 words
The method of claim 15 , wherein using includes determining the number of exposures analyzed.
Claim 21
Independent Claim
133 words
A method of providing printability analysis for a defect on a physical mask, the method comprising: generating a simulated wafer image of the physical mask; identifying a first feature on the simulated wafer image affected by the defect; identifying a second feature on the simulated wafer image unaffected by the defect, wherein the first and second features have substantially the same critical dimension in the absence of the defect; computing a first critical dimension deviation for a defect-free area of the physical mask using the simulated water images of the physical and reference masks; computing a second critical dimension deviation for a detect area of the physical mask using the simulated wafer images of the physical and reference masks; and using the first and second critical dimension deviations to provide the printability analysis.
Claim 22
Independent Claim
133 words
A method of providing printability analysis for a defect on a physical mask, the method comprising: generating a simulated wafer image of the physical mask; identifying a first feature on the simulated wafer image affected by the defect; identifying a second feature on the simulated wafer image unaffected by the defect, wherein the first and second features have substantially the same critical dimension in the absence of the defect; computing a first critical dimension deviation for a defect-free area of the physical mask using the simulated water images of the physical and reference masks; computing a second critical dimension deviation for a detect area of the physical mask using the simulated wafer images of the physical and reference masks; and using the first and second critical dimension deviations to provide the printability analysis.
Claim 23
Dependent Claim
15 words
The method of claim 18 , further including determining a tolerance for critical dimension changes.
Claim 24
Dependent Claim
21 words
The method of claim 19 , wherein using includes using the tolerance for critical dimension changes to provide the printability analysis.
Claim 25
Dependent Claim
15 words
The method of claim 19 , wherein using includes determining the number of exposures analyzed.
Claim 26
Independent Claim
151 words
A method of fabricating a physical mask, the method comprising: designing an integrated circuit; creating mask design data for a layer of the integrated circuit; manufacturing a physical mask conforming to the mask design data; inspecting the physical mask based on a simulated wafer image of the physical mask and a simulated wafer image of a reference mask, wherein the reference mask corresponds to a defect-free physical mask, wherein inspecting comprises: computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks; computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks; and using the average critical dimension deviation and the maximum critical dimension deviation to provide printability analysis; and determining whether the physical mask passes inspection based on the printability analysis.
Claim 27
Independent Claim
151 words
A method of fabricating a physical mask, the method comprising: designing an integrated circuit; creating mask design data for a layer of the integrated circuit; manufacturing a physical mask conforming to the mask design data; inspecting the physical mask based on a simulated wafer image of the physical mask and a simulated wafer image of a reference mask, wherein the reference mask corresponds to a defect-free physical mask, wherein inspecting comprises: computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks; computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks; and using the average critical dimension deviation and the maximum critical dimension deviation to provide printability analysis; and determining whether the physical mask passes inspection based on the printability analysis.
Claim 28
Dependent Claim
20 words
The method of claim 22 , wherein inspecting includes: using a tolerance for critical dimension changes to provide printability analysis.
Claim 29
Dependent Claim
35 words
The method of claim 23 , wherein inspecting further includes determining a defect severity score based on using the average critical, dimension deviation, the maximum critical dimension deviation, and the tolerance for critical dimension changes.
Claim 30
Dependent Claim
15 words
The method of claim 22 , wherein using includes determining the number of exposures analyzed.
Claim 31
Dependent Claim
20 words
The method of claim 25 , wherein the printability analysis includes a defect severity score for at least one exposure.
Claim 32
Dependent Claim
18 words
The method of claim 25 , wherein the printability analysis includes a defect severity score for multiple exposures.
Claim 33
Independent Claim
85 words
A method of generating a defect severity score for a defect on a mask, the method comprising: providing two-dimensional analysis on the defect and a first feature on the mask, the first feature being proximate to the defect; providing a first wafer image of the mask; and providing defect analysis on a second feature on the wafer image, the second feature corresponding to the first feature being simulated, wherein providing defect analysis includes computing various critical dimension deviations based on the first and second features.
Claim 34
Independent Claim
85 words
A method of generating a defect severity score for a defect on a mask, the method comprising: providing two-dimensional analysis on the defect and a first feature on the mask, the first feature being proximate to the defect; providing a first wafer image of the mask; and providing defect analysis on a second feature on the wafer image, the second feature corresponding to the first feature being simulated, wherein providing defect analysis includes computing various critical dimension deviations based on the first and second features.
Claim 35
Independent Claim
157 words
A method of generating a defect severity score for a defect on a mask, the method comprising: providing two-dimensional analysis on the defect and a first feature on the mask, the first feature being proximate to the defect; providing a first wafer image of the mask; providing defect analysis on a second feature on the wafer image, the second feature corresponding to the first feature being simulated, wherein providing defect analysis includes computing various critical dimension deviations based on the first and second features; identifying a third feature on a defect-free reference image of the mask, the third feature representing the first feature; providing a second wafer image of the reference image, the second wafer image including a fourth feature, the fourth feature corresponding to the third feature being simulated; and providing defect analysis on the fourth feature, wherein providing defect analysis includes computing various critical dimension deviations based on the first, second, third, and fourth features.
Claim 36
Independent Claim
157 words
A method of generating a defect severity score for a defect on a mask, the method comprising: providing two-dimensional analysis on the defect and a first feature on the mask, the first feature being proximate to the defect; providing a first wafer image of the mask; providing defect analysis on a second feature on the wafer image, the second feature corresponding to the first feature being simulated, wherein providing defect analysis includes computing various critical dimension deviations based on the first and second features; identifying a third feature on a defect-free reference image of the mask, the third feature representing the first feature; providing a second wafer image of the reference image, the second wafer image including a fourth feature, the fourth feature corresponding to the third feature being simulated; and providing defect analysis on the fourth feature, wherein providing defect analysis includes computing various critical dimension deviations based on the first, second, third, and fourth features.
Claim 37
Dependent Claim
26 words
The method of claim 29 , wherein providing defect analysis on the second and fourth features includes comparing critical dimensions on the second and fourth features.
Claim 38
Dependent Claim
21 words
The method of claim 30 , wherein providing defect analysis further includes determining changes of the critical dimensions at different exposures.
Claim 39
Dependent Claim
21 words
The method of claim 31 , wherein providing defect analysis further includes determining a maximum critical dimension change for each exposure.
Claim 40
Dependent Claim
22 words
The method of claim 32 , wherein providing defect analysis further includes calculating a relative maximum critical dimension change for each exposure.
Claim 41
Dependent Claim
18 words
The method of claim 29 , further including providing a calibration between the first and second wafer images.
Claim 42
Independent Claim
159 words
A system for analyzing a defect on a physical mask, the system comprising: an inspection tool for generating a mask image from the physical mask and a reference image from a reference mask; a wafer image generator for simulating a stepper mask image from the mask image and a stepper reference image from the reference image; and a defect printability analysis generator for comparing the stepper mask image and the stepper reference image, wherein the defect printability analysis generator determines an average critical dimension deviation for a defect-free area on the physical mask using the stepper mask image and the stepper reference image, wherein the defect printability analysis generator determines a maximum critical dimension deviation for a defect area on the physical mask using the stepper mask image and the stepper reference image, and wherein the defect printability analysis generator uses the average critical dimension deviation and the maximum critical dimension deviation to provide printability analysis of the defect.
Claim 43
Independent Claim
159 words
A system for analyzing a defect on a physical mask, the system comprising: an inspection tool for generating a mask image from the physical mask and a reference image from a reference mask; a wafer image generator for simulating a stepper mask image from the mask image and a stepper reference image from the reference image; and a defect printability analysis generator for comparing the stepper mask image and the stepper reference image, wherein the defect printability analysis generator determines an average critical dimension deviation for a defect-free area on the physical mask using the stepper mask image and the stepper reference image, wherein the defect printability analysis generator determines a maximum critical dimension deviation for a defect area on the physical mask using the stepper mask image and the stepper reference image, and wherein the defect printability analysis generator uses the average critical dimension deviation and the maximum critical dimension deviation to provide printability analysis of the defect.
Claim 44
Dependent Claim
42 words
The system of claim 35 , further including a critical region identification generator for determining if the defect is located in a critical region of the physical mask, the critical region identification generator providing an output to the defect printability analysis generator.
Claim 45
Dependent Claim
28 words
The system of claim 35 , further including a bitmap editor for receiving data from the defect printability analysis generator and providing a suggested repair to the defect.
Claim 46
Dependent Claim
18 words
The system of claim 37 , further including a mask repair tool for responding to the suggested repair.
Claim 47
Dependent Claim
24 words
The system of claim 38 , wherein the system automatically analyzes the defect and the mask repair tool automatically responds to the suggested repair.
Claim 48
Dependent Claim
27 words
The system of claim 35 , wherein the system automatically analyzes the defect and the defect printability analysis generator automatically provides a severity score for the defect.
Claim 49
Independent Claim
158 words
A system for generating a defect severity score for a defect on a physical mask, the system comprising: means for generating a first image of a feature on the physical mask proximate to the defect and a second image of the feature on the reference image; means for simulating a first wafer image of the first image and a second wafer image of the second image; and means for generating the defect severity score based on the first and second wafer images, wherein the means for generating determines an average critical dimension deviation for a defect-free area on the physical mask using the first and second wafer images, wherein the means for generating determines a maximum critical dimension deviation for a defect area on the physical mask using the first and second wafer images, and wherein the means for generating uses the average critical dimension deviation and the maximum critical dimension deviation to provide the defect severity score.
Claim 50
Independent Claim
158 words
A system for generating a defect severity score for a defect on a physical mask, the system comprising: means for generating a first image of a feature on the physical mask proximate to the defect and a second image of the feature on the reference image; means for simulating a first wafer image of the first image and a second wafer image of the second image; and means for generating the defect severity score based on the first and second wafer images, wherein the means for generating determines an average critical dimension deviation for a defect-free area on the physical mask using the first and second wafer images, wherein the means for generating determines a maximum critical dimension deviation for a defect area on the physical mask using the first and second wafer images, and wherein the means for generating uses the average critical dimension deviation and the maximum critical dimension deviation to provide the defect severity score.
Claim 51
Dependent Claim
35 words
The system of claim 41 , further including means for identifying if the defect is within a critical region, wherein the means for identifying provides data to the means for generating the defect severity score.
Claim 52
Dependent Claim
21 words
The system of claim 41 , wherein the means for simulating includes means for responding to a plurality of lithographic conditions.
Claim 53
Dependent Claim
119 words
An integrated circuit fabricated using a physical mask made by the following steps: generating a simulated wafer image of the physical mask; generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask; computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks; computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks; using the average critical dimension deviation and the maximum critical dimension deviation to determine whether to repair the physical mask; and fabricating the integrated circuit using the physical mask.
Claim 54
Dependent Claim
119 words
An integrated circuit fabricated using a physical mask made by the following steps: generating a simulated wafer image of the physical mask; generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask; computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks; computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks; using the average critical dimension deviation and the maximum critical dimension deviation to determine whether to repair the physical mask; and fabricating the integrated circuit using the physical mask.
Claim 55
Dependent Claim
121 words
Computer software for analyzing a defect on a first mask, the software including: means for generating a simulated wafer image of the first mask; means for generating a simulated wafer image of a second mask, the second mask corresponding to a defect-free first mask; and means for computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks; means for computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks; and means for using the average critical dimension deviation and the maximum critical dimension deviation to provide printability analysis regarding the defect.
Claim 56
Dependent Claim
121 words
Computer software for analyzing a defect on a first mask, the software including: means for generating a simulated wafer image of the first mask; means for generating a simulated wafer image of a second mask, the second mask corresponding to a defect-free first mask; and means for computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks; means for computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks; and means for using the average critical dimension deviation and the maximum critical dimension deviation to provide printability analysis regarding the defect.
Claim 57
Dependent Claim
23 words
The computer software of claim 45 , wherein the means for using includes: means for generating a defect severity score for the defect.
Claim 58
Dependent Claim
21 words
The computer software of claim 45 , further including: means for providing repair information on the defect based on the printability.
Claim 59
Dependent Claim
23 words
The computer software of claim 46 , further including: means for providing repair information on the defect based on the defect severity score.
Claim 60
Independent Claim
116 words
A method of inspecting a physical mask, the physical mask including a defect, the method comprising the following steps: generating a simulated wafer image of the physical mask; generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask; computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks; computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks; and using the average critical dimension deviation and the maximum critical dimension deviation to provide printability analysis of the defect.
Claim 61
Independent Claim
116 words
A method of inspecting a physical mask, the physical mask including a defect, the method comprising the following steps: generating a simulated wafer image of the physical mask; generating a simulated wafer image of a reference mask, the reference mask corresponding to a defect-free physical mask; computing an average critical dimension deviation for a defect-free area of the physical mask using the simulated wafer images of the physical and reference masks; computing a maximum critical dimension deviation for a defect area of the physical mask using the simulated wafer images of the physical and reference masks; and using the average critical dimension deviation and the maximum critical dimension deviation to provide printability analysis of the defect.
Claim 62
Dependent Claim
14 words
The method of claim 49 , wherein comparing includes generating a defect severity score.
Claim 63
Dependent Claim
19 words
The method of claim 49 , further including: communicating the information on the defect to a mask repair tool.
Claim 64
Dependent Claim
18 words
The method of claim 50 , further including: communicating the defect severity score to a mask repair tool.
Claim 65
Dependent Claim
58 words
The method of claim 49 , wherein the reference mask includes one of the following: a simulated image of a layout of the physical mask, a defect-free area of the physical mask having a substantially identical pattern to that including the defect, and a simulated image of the physical mask as the physical mask is processed in manufacturing.
Claim 66
Dependent Claim
23 words
The method of claim 49 , wherein generating the simulated image of the physical mask compensates for image distortions created during image capture.
References Cited (Backward Citations)
US4809341A
Cited
EP0306275A2
Cited
US5572598A
Cited
US5326659A
Cited
US5340700A
Cited
US5432714A
Cited
US5815685A
Cited
US5825647A
Cited
WO1997013370A1
Cited
US5900338A
Cited
US5801954A
Cited
US6130750A
Cited
US5862058A
Cited
US5849440A
Cited
US5795688A
Cited
US6076465A
Cited
WO1998020327A1
Cited
US5804340A
Cited
WO1998045685A1
Cited
US6081659A
Cited
US6078738A
Cited
US6016357A
Cited
US6578188B1
Cited
US20020019729A1
Cited
WO1999014706A3
Cited
WO1999014706A2
Cited
US6009251A
Cited
US6009250A
Cited
US6011911A
Cited
US5965306A
Cited
WO1999038002A1
Cited
US6023328A
Cited
US6272236B1
Cited
US6091845A
Cited
WO1999056113A1
Cited
WO1999059200A1
Cited
WO1999067626A1
Cited
US6334209B1
Cited
US6272392B1
Cited
WO2000036525A2
Cited
WO2000036525A3
Cited
US6171731B1
Cited
WO2000067074A1
Cited
WO2000067075A1
Cited
DE10037697A1
Cited
JP2001056306A
Cited
US6346426B1
Cited
US20020164064A1
Cited
US20020164065A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2008-03-28 | 2008-09-27 | 2009-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2012-03-28 | 2012-09-27 | 2013-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2016-03-28 | 2016-09-27 | 2017-03-29 | $7700.00 | Window Closed / Lapsed |