Selection of wavelengths for integrated circuit optical metrology
First Claim
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1. A method of selecting wavelengths for use in optical metrology of an integrated circuit having a nominal profile, the method comprising:
- determining one or more termination criteria;
determining one or more selection criteria;
creating a correlation matrix for a set of diffraction spectra measured at optical metrology measurement points, the measurement points corresponding to specified wavelengths, each row and each column corresponding to one of the specified wavelengths, the correlation matrix having as matrix members correlation coefficients calculated from the diffraction spectrum values of the wavelengths corresponding to the row and column of the matrix member;
selecting wavelengths using the set of diffraction spectra for the integrated circuit structure, the correlation matrix, the selection criteria, and a wavelength selection algorithm; and
performing the selecting step until the termination criteria are met.
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Abstract
Specific wavelengths to use in optical metrology of an integrated circuit can be selected using one or more selection criteria and termination criteria. Wavelengths are selected using the selection criteria, and the selection of wavelengths is iterated until the termination criteria are met.
28 Citations
20 Claims
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1. A method of selecting wavelengths for use in optical metrology of an integrated circuit having a nominal profile, the method comprising:
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determining one or more termination criteria; determining one or more selection criteria; creating a correlation matrix for a set of diffraction spectra measured at optical metrology measurement points, the measurement points corresponding to specified wavelengths, each row and each column corresponding to one of the specified wavelengths, the correlation matrix having as matrix members correlation coefficients calculated from the diffraction spectrum values of the wavelengths corresponding to the row and column of the matrix member; selecting wavelengths using the set of diffraction spectra for the integrated circuit structure, the correlation matrix, the selection criteria, and a wavelength selection algorithm; and performing the selecting step until the termination criteria are met. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for selecting wavelengths for use in optical metrology of an integrated circuit having a nominal profile, the system comprising:
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an input device for specifying one or more termination criteria and one or more selection criteria; and a wavelength selector configured to; create a correlation matrix for a set of diffraction spectra measured at optical metrology measurement points, the measurement points corresponding to specified wavelengths, each row and each column corresponding to one of the specified wavelengths, the correlation matrix having as matrix members correlation coefficients calculated from the diffraction spectrum values of the wavelengths corresponding to the row and column of the matrix member; until the termination criteria are met, select wavelengths using the set of diffraction spectra for the integrated circuit structure, the correlation matrix, the selection criteria, and a wavelength selection algorithm. - View Dependent Claims (11, 12)
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13. A computer-readable storage medium containing computer executable instructions for selecting wavelengths for use in optical metrology of an integrated circuit having a nominal profile, comprising instructions for:
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determining one or more termination criteria; determining one or more selection criteria; creating a correlation matrix for a set of diffraction spectra measured at optical metrology measurement points, the measurement points corresponding to specified wavelengths, each row and each column corresponding to one of the specified wavelengths, the correlation matrix having as matrix members correlation coefficients calculated from the diffraction spectrum values of the wavelengths corresponding to the row and column of the matrix member; selecting wavelengths using the set of diffraction spectra for the integrated circuit structure, the correlation matrix, the selection criteria, and a wavelength selection algorithm; and performing the selecting step until the termination criteria are met. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20)
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Specification