Model and parameter selection for optical metrology
First Claim
1. A method of selecting a profile model and selecting parameters of the profile model for use in optical metrology of structures in a wafer, the method comprising:
- a) setting one or more termination criteria;
b) setting one or more parameter selection criteria;
c) selecting a profile model for use in optical metrology of a structure in a wafer, the profile model having a set of geometric parameters associated with dimensions of the structure;
d) selecting a set of optimization parameters for the profile model using one or more input measured diffraction signals and the one or more parameter selection criteria, wherein the set of optimization parameters is converted from the set of geometric parameters, and wherein the number of optimization parameters within the set of optimization parameters is less than the number of geometric parameters within the set of geometric parameters;
e) testing the selected profile model and the set of optimization parameters against the one or more termination criteria; and
f) performing the steps c, d, and e until the one or more termination criteria are met.
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Abstract
A profile model for use in optical metrology of structures in a wafer is selected, the profile model having a set of geometric parameters associated with the dimensions of the structure. A set of optimization parameters is selected for the profile model using one or more input diffraction signals and one or more parameter selection criteria. The selected profile model and the set of optimization parameters are tested against one or more termination criteria. The process of selecting a profile model, selecting a set of optimization parameters, and testing the selected profile model and set of optimization parameters is performed until the one or more termination criteria are met.
87 Citations
52 Claims
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1. A method of selecting a profile model and selecting parameters of the profile model for use in optical metrology of structures in a wafer, the method comprising:
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a) setting one or more termination criteria; b) setting one or more parameter selection criteria; c) selecting a profile model for use in optical metrology of a structure in a wafer, the profile model having a set of geometric parameters associated with dimensions of the structure; d) selecting a set of optimization parameters for the profile model using one or more input measured diffraction signals and the one or more parameter selection criteria, wherein the set of optimization parameters is converted from the set of geometric parameters, and wherein the number of optimization parameters within the set of optimization parameters is less than the number of geometric parameters within the set of geometric parameters; e) testing the selected profile model and the set of optimization parameters against the one or more termination criteria; and f) performing the steps c, d, and e until the one or more termination criteria are met. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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26. A method of determining wafer structure having critical dimensions, profile shape, and film thickness using optical metrology, the method comprising:
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a) setting one or more termination criteria; b) setting one or more parameter selection criteria; c) selecting a profile mode!for use in optical metrology of a structure in a wafer, the profile model having a set of geometric parameters associated with dimensions of the structure, the profile model having critical dimensions, profile shape, and film thickness; d) selecting a set of optimization parameters for the profile model using one or more input measured diffraction signals and the one or more parameter selection criteria, wherein the set of optimization parameters is converted from the set of geometric parameters, and wherein the number of optimization parameters within the set of optimization parameters is less than the number of geometric parameters within the set of geometric parameters; e) testing the selected profile model and the set of optimization parameters against the one or more termination criteria; f) performing the steps c, d, and e until the one or more termination criteria are met; and g) assessing critical dimensions, profile shape, and film thickness associated with the selected profile model and selected optimization parameters of the selected profile model. - View Dependent Claims (27)
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28. A method of creating a library of optical metrology signals and associated profiles for structures in a wafer, the method comprising:
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a) setting one or more termination criteria; b) setting one or more parameter selection criteria; c) selecting a profile model for use in optical metrology of a structure in a wafer, the profile model having a set of geometric parameters associated with dimensions of the structure, the profile model having critical dimensions, profile shape, and film thickness; d) selecting a set of optimization parameters for the profile model using one or more input measured diffraction signals and the one or more parameter selection criteria, wherein the set of optimization parameters is converted from the set of geometric parameters, and wherein the number of optimization parameters within the set of optimization parameters is less than the number of geometric parameters within the set of geometric parameters; e) testing the selected profile model and the set of optimization parameters against the one or more termination criteria; f) performing the steps c, d, and e until the one or more termination criteria are met; g) assessing critical dimensions, profile shape, and film thickness associated with the selected profile model and selected optimization parameters of the selected profile model; and h) creating a library of diffraction signals and associated profile data using the selected optimization parameters of the selected profile model.
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29. A system for processing optical metrology data for wafer structures, the system comprising:
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a model generator configured to generate a profile model for a structure in a wafer using characterizations of the structure and to process one or more termination criteria and one or more parameter selection criteria; an optical metrology simulator configured to use the profile model and selected optimization parameter values to calculate a simulated diffraction signal; a parameter selector coupled to the model generator and to the optical metrology simulator, the parameter selector configured to perform calculations of one or more parameter selection criteria values using one or more input measured diffraction signals, to compare the calculated one or more parameter selection criteria values to the one or more parameter selection criteria, and to select optimization parameters that meet the one or more parameter selection criteria, wherein the optimization parameters are converted from a set of geometric parameters, and wherein the number of optimization parameters is less than the number of geometric parameters within the set of geometric parameters; and a profile model tester coupled to the parameter selector, the profile model tester configured to perform calculations of termination values, to compare the calculated termination values to the one or more termination criteria, and to adjust the profile model if the one or more termination criteria are not met. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38)
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39. A wafer structure critical dimension server system comprising:
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a metrology model optimizer configured to; a) set one or more termination criteria; b) set one or more parameter selection criteria; c) select a profile model for use in optical metrology of a structure in a wafer, the profile model having a set of geometric parameters associated with dimensions of the structure; d) select a set of optimization parameters for the profile model using one or more input measured diffraction signals and the one or more parameter selection criteria, wherein the set of optimization parameters is converted from the set of geometric parameters, and wherein the number of optimization parameters within the set of optimization parameters is less than the number of geometric parameters within the set of geometric parameters; e) test the selected profile model and the set of optimization parameters against the one or more termination criteria; and f) perform steps c, d, and e until the one or more termination criteria are met; and a profiler workstation coupled to the metrology model optimizer, the profiler workstation configured to; a) receive input regarding wafer structure profiles, the metrology model specifications, the one or more termination criteria, and the one or more parameter selection criteria; and b) display output information comprising critical dimensions, profile shape, and film thickness of the wafer structures. - View Dependent Claims (40, 41)
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42. A system for real-time determination of profile data of wafer structures, the system comprising:
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an optical metrology system configured to measure diffraction signals off wafer structures; a metrology model optimizer coupled to the optical metrology system, the metrology model optimizer configured to; process characterization of wafer structure profiles, metrology model specifications, one or more termination criteria, and one or more parameter selection criteria; generate one or more profile models of the wafer structures, the profile models having associated parameters; select a set of optimization parameters of the profile model using one or more input measured diffraction signals the selected optimization parameters meeting the one or more selection criteria, wherein the optimization parameters are converted from a set of geometric parameters, and wherein the number of optimization parameters is less than the number of geometric parameters within the set of geometric parameters; and perform the generation of one or more profile models and selection of optimization parameters of the model, the selected optimization parameters meeting the one or more parameter selection criteria until the one or more termination criteria are met; a profiler workstation coupled to the metrology model optimizer, the profiler workstation configured to; receive input regarding the wafer structure profiles, the metrology model specifications, the one or more termination criteria, and the one or more parameter selection criteria; and display output information comprising critical dimensions, profile shape, and film thickness of the wafer structures; and a data store coupled to the profile model tester, the data store configured to; store identification data associated with the structure, the wafer, and the selected model and data about the termination criteria, the one or more parameter selection criteria, and the selected optimization parameters. - View Dependent Claims (43)
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44. A computer-readable storage medium containing computer executable code to select a profile model for use in integrated circuit optical metrology, comprising instructions for:
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a) setting one or more termination criteria; b) setting one or more parameter selection criteria; c) selecting a profile model for use in optical metrology of a structure in a wafer, the profile model having a set of geometric parameters associated with dimensions of the structure; d) selecting a set of optimization parameters for the profile model using one or more input measured diffraction signals and the one or more parameter selection criteria, wherein the set of optimization parameters is converted from the set of geometric parameters, and wherein the number of optimization parameters within the set of optimization parameters is less than the number of geometric parameters within the set of geometric parameters; e) testing the selected profile model and the set of optimization parameters against the one or more termination criteria; and f) performing the steps c, d, and e until the one or more termination criteria arc met. - View Dependent Claims (45, 46, 47, 48, 49)
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50. A computer-readable storage medium containing computer executable code to select a profile model for use in integrated circuit optical metrology by instructing a computer to operate as follows:
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a) setting one or more termination criteria; b) setting one or more parameter selection criteria; c) selecting a profile model for use in optical metrology of a structure in a wafer, the profile model having a set of geometric parameters associated with dimensions of the structure, the profile model having critical dimensions, profile shape, and film thickness; d) selecting a set of optimization parameters for the profile model using one or more input measured diffraction signals and the one or more parameter selection criteria, wherein the set of optimization parameters is converted from the set of geometric parameters, and wherein the number of optimization parameters within the set of optimization parameters is less than the number of geometric parameters within the set of geometric parameters; e) testing the selected profile model and the set of optimization parameters against the one or more termination criteria; f) performing the steps c, d, and e until the one or more termination criteria are met; and g) assessing critical dimensions, profile shape, and film thickness associated with the selected profile model and selected optimization parameters or the selected profile model.
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51. A computer-readable storage medium containing computer executable code to select a profile model for use in integrated circuit optical metrology by instructing a computer to operate as follows:
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a) setting one or more termination criteria; b) selling one or more parameter selection criteria; c) selecting a profile model for use in optical metrology of a structure in a wafer, the profile model having a set of geometric parameters associated with dimensions of the structure, the profile model having critical dimensions, profile shape, and film thickness; d) selecting a set of optimization parameters for the profile model using one or more input measured diffraction signals and the one or more parameter selection criteria, wherein the set of optimization parameters is converted from the set of geometric parameters, and wherein the number of optimization parameters within the set of optimization parameters is less than the number of geometric parameters within the set of geometric parameters; e) testing the selected profile model and the set of optimization parameters against the one or more termination criteria; f) performing the steps c, d, and e until the one or more termination criteria are met; g) assessing critical dimensions, profile shape, and film thickness associated with the selected profile model and selected optimization parameters of the selected profile model; and h) creating a library of diffraction signals and associated profile data using the selected optimization parameters of the selected profile model. - View Dependent Claims (52)
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Specification