| US 7,474,993 B2 | ||
| Selection of wavelengths for integrated circuit optical metrology | ||
| Srinivas Doddi, Fremont, Calif. (US); Lawrence Lane, San Jose, Calif. (US); Vi Vuong, Fremont, Calif. (US); Michael Laughery, Austin, Tex. (US); Junwei Bao, Palo Alto, Calif. (US); Kelly Barry, Saratoga, Calif. (US); Nickhil Jakatdar, Los Altos, Calif. (US); and Emmanuel Drege, San Jose, Calif. (US) | ||
| Assigned to Timbre Technologies, Inc., Santa Clara, Calif. (US) | ||
| Filed on Apr. 20, 2007, as Appl. No. 11/788,735. | ||
| Application 11/788735 is a division of application No. 10/162516, filed on Jun. 03, 2002, granted, now 7,216,045. | ||
| Prior Publication US 2007/0198211 A1, Aug. 23, 2007 | ||
| Int. Cl. G01R 13/00 (2006.01); G01R 31/26 (2006.01) | ||
| U.S. Cl. 702—196 [702/66; 702/159; 702/172; 438/16] | 20 Claims |
| 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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