EP0313013A2
Expired / Lapsed
EP
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System for modeling and displaying lithographic process
Assignee: Shipley Co Inc
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Filing: 1988-10-19
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Granted: —
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Expires: 2008-10-19
Abstract
Abstract A lithographic process analysis and control system which provides a modeled version of a lithographic process in the dimensions of feature width, focus and exposure. This system uses the model to quickly determine the range of focus and exposure limits for obtaining the desired feature width. The system has flexible graphic display capability for displaying graphic representations of the data as measured and modeled.
Inventors
- 👤 Christopher P. Ausschnitt
- 👤 Edward A. Mcfadden
- 👤 Raul V. Tan
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 17:24
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70483; G03F7/7055; G03F7/70558; G03F7/70605; G03F7/70616; G03F7/70641; G03F7/708
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
60 words
A lithography process analysis system comprising: means for receiving feature width, exposure and focus data; means for filing said data in a memory; means for determining the best fit of said data on a critical dimension model; means for displaying said best fit model of said data on a three dimensional graph whose axes are feature width, exposure and focus.
Claim 2
Dependent Claim
60 words
A lithography process analysis system comprising: means for receiving feature width, exposure and focus data; means for filing said data in a memory; means for determining the best fit of said data on a critical dimension model; means for displaying said best fit model of said data on a three dimensional graph whose axes are feature width, exposure and focus.
Claim 3
Dependent Claim
15 words
The lithographic process analysis system of claim 1 wherein said-CD model comprises the following equation:
Claim 4
Dependent Claim
25 words
The lithographic process analysis system of claim 1 wherein said means for best fitting a critical dimension model comprises means for performing linear regression analysis.
Claim 5
Dependent Claim
36 words
The lithographic process analysis system of claim 1 further comprising means for displaying a three dimensional graph whose axes are measured feature width, measured exposure and measured focus alongside said graph of said best fit model.
Claim 6
Dependent Claim
38 words
The lithographic process analysis system of claim 1 further comprising means for displaying a three dimensional graph of the measured data in feature width, focus and exposure overlaid on the three dimensional graph of the best fit model.
Claim 7
Dependent Claim
23 words
The lithographic process analysis system of claim 1 further comprising means for determining a range of focus from a predetermined maximum exposure latitude.
Claim 8
Dependent Claim
23 words
The lithographic process analysis system of claim 1 further comprising means for determining a range of focus from a predetermined minimum sidewall angle.
Claim 9
Dependent Claim
29 words
The lithographic process analysis system of claim 1 further comprising means for displaying a two dimensional graph in any of the two dimensions used in said three dimensional graph.
Claim 10
Dependent Claim
23 words
The lithographic process analysis system of claim 1 further comprising means for displaying a two dimensional graph overlaid on a three dimensional graph.
Claim 11
Dependent Claim
85 words
A lithographic analysis and control system comprising: means for determining a largest available window focus and exposure by best fitting experimental focus, exposure and feature width data into a critical dimension model; means for receiving feature width measurements from the lithographic process being controlled; means for identifying a shift in exposure from said feature width measurements and exposure latitude at the operating exposure and focus as determined from the best fit model; and means for generating a correction signal to correct the shift in exposure.
Claim 12
Dependent Claim
85 words
A lithographic analysis and control system comprising: means for determining a largest available window focus and exposure by best fitting experimental focus, exposure and feature width data into a critical dimension model; means for receiving feature width measurements from the lithographic process being controlled; means for identifying a shift in exposure from said feature width measurements and exposure latitude at the operating exposure and focus as determined from the best fit model; and means for generating a correction signal to correct the shift in exposure.
Claim 13
Independent Claim
107 words
A method for controlling a lithographic process comprising: determining a largest available window in focus and exposure by best fitting experimental focus, exposure and feature width data onto a critical dimension model; receiving feature width measurements from the lithographic process being controlled; determining the minimum and maximum feature widths over a period of time; determining maximum and minimum effective exposures from said minimum and maximum feature widths and exposure latitude from the critical dimension model; providing a correction signal to said lithographic process to correct for a shift in the midpoint between maximum and minimum exposure away from the optimal exposure setting of the largest available window.
Claim 14
Independent Claim
107 words
A method for controlling a lithographic process comprising: determining a largest available window in focus and exposure by best fitting experimental focus, exposure and feature width data onto a critical dimension model; receiving feature width measurements from the lithographic process being controlled; determining the minimum and maximum feature widths over a period of time; determining maximum and minimum effective exposures from said minimum and maximum feature widths and exposure latitude from the critical dimension model; providing a correction signal to said lithographic process to correct for a shift in the midpoint between maximum and minimum exposure away from the optimal exposure setting of the largest available window.
Claim 15
Dependent Claim
114 words
The method of claim 11 wherein said step of determining a largest available window includes the steps of: measuring feature width as a function of focus and exposure; best fitting the measurements of feature width, focus and exposure to a critical dimension model which. inherently provides an optimum focus; determining the value of optimal exposure in the critical dimension model when focus equals the optimum focus and feature width equals a predetermined desired width; determining a range of focus by applying a predetermined maximum exposure latitude to the critical dimension model at the optimal exposure; determining a range of exposure by dividing a predetermined range of feature width by said predetermined maximum exposure latitude.
References Cited (Backward Citations)
No citation records indexed.
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