Film thickness and free carrier concentration analysis method and apparatus
US5604581A · kind A · utility
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29Claims
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Key dates
| Filing date | Oct 7, 1994 |
| Grant date | Feb 18, 1997 |
| Priority date | — |
| Expiry date | Oct 7, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/0625
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The method determines the thickness and the free carrier concentration of at least one layer of a structure. An exposed surface of the structure is irradiated using spectral radiation, and the measured reflectance spectrum is compared to a calculated spectrum. Using algorithms that include terms representative of complex refractive indices, layer thickness, dielectric constants, and free carrier concentrations, values are iteratively assigned to the thickness and free carrier concentration parameters so as to produce a best fit relationship between the compared spectra, and to thereby determine those parameters.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.