| US 7,453,562 B1 | ||
| Ellipsometry measurement and analysis | ||
| Torsten R. Kaack, Los Altos, Calif. (US); Shankar Krishnan, Santa Clara, Calif. (US); and Fabio A. Faccini, San Jose, Calif. (US) | ||
| Assigned to KLA-Tencor Corporation, San Jose, Calif. (US) | ||
| Filed on Sep. 28, 2007, as Appl. No. 11/863,334. | ||
| Claims priority of provisional application 60/970294, filed on Sep. 06, 2007. | ||
| Int. Cl. G01N 21/00 (2006.01) | ||
| U.S. Cl. 356—237.2 | 20 Claims |
| 1. A method of performing a measurement of properties of a sample, the method comprising the steps of:
directing a first beam of light at a first wavelength and having a first energy at the sample for a first length of time,
where a combination of the first wavelength, the first energy, and the first length of time is sufficient to cause temporary
damage to the sample, the damage including at least one of atomic changes and molecular changes to the sample,
reflecting the first beam of light from the sample to create a first reflected beam having properties indicative of the properties
of the sample,
sensing the properties of the first reflected beam to create a first electrical signal indicative of the properties of the
sample,
waiting a length of time sufficient for the temporary damage to the sample to substantially heal,
directing a second beam of light at a second wavelength and having a second energy at the sample for a second length of time,
where a combination of the second wavelength, the second energy, and the second length of time is sufficient to cause temporary
damage to the sample, the damage including at least one of atomic changes and molecular changes to the sample,
reflecting the second beam of light from the sample to create a second reflected beam having properties indicative of the
properties of the sample,
sensing the properties of the second reflected beam to create a second electrical signal indicative of the properties of the
sample, and
analyzing the first and second electrical signals to determine the properties of the sample.
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