Method and apparatus for optically determining physical parameters of thin films deposited on a complex substrate
US6392756B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 18, 1999 |
| Grant date | May 21, 2002 |
| Priority date | — |
| Expiry date | Jun 18, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/0641
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and an apparatus for optically determining a physical parameter such as thickness t, index of refraction n, extinction coefficient k or a related physical parameter such as energy bandgap Eg of a thin film. A test beam having a wavelength range &Dgr;&lgr; is used to illuminate the thin film after it is deposited on a complex substrate which has at least two layers and exhibits a non-monotonic and an appreciably variable substrate optical response over wavelength range &Dgr;&lgr;. Alternatively, the thin film can be deposited between the at least two layers of the complex substrate. A measurement of a total optical response, consisting of the substrate optical response and an optical response difference due to the thin film is performed over wavelength range &Dgr;&lgr;. The at least two layers making up the complex substrate are chosen such that the effect of multiple internal reflections in the complex substrate and the film is maximized. The physical parameters are determined from the total optical response which can be in the form of a reflected and/or a transmitted beam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.