Method and apparatus for measuring the composition and other properties of thin films utilizing infrared radiation
US6485872B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 22, 2000 |
| Grant date | Nov 26, 2002 |
| Priority date | — |
| Expiry date | Jan 26, 2021 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/145
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The composition, free carrier concentrations, and other properties of thin films and graded layers embedded in film stack structures are measured by the method of the invention, which is based upon the application of two novel algorithms to extract the composition of a measured layer independently of the confounding effects of additional layers, and which can be effected even when calibration samples are not available with the same layered structure as the samples to be measured. The method uses sample model-based analysis algorithms to extract the dielectric function of the layer to be measured, combined with model-based analysis to relate the composition of the layer to its dielectric function. Because the dielectric function of a layer is a bulk spectral property of the material, and is inherently independent of the thickness of the layer, the composition of the material can be determined more easily and unambiguously from its dielectric function than from raw spectral quantities such as reflectance, ellipsometry, and transmittance, which spectral data are influenced strongly by the optical properties of the overlayers, the underlayers, and the substrate material. The method ena…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.