Temperature measuring method and apparatus
US6082892A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 10, 1997 |
| Grant date | Jul 4, 2000 |
| Priority date | — |
| Expiry date | Oct 10, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01J5/601
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of remotely measuring the temperature of a body, such as a semiconductor wafer, whose transparency varies with both wavelength and temperature and is characterized by an optical absorption edge. The body is illuminated at wavelengths on either side of the optical absorption edge. Based on the measured reflectivity at wavelengths shorter than the optical absorption edge, the direct reflectivity at wavelengths longer than the optical absorption edge is predicted and used to estimate the component of total reflectivity, at wavelengths longer than the optical absorption edge, which corresponds to propagation through the body and reflection back through the body. Light reflected from the body, measured in an "active" channel, is distinguished from light emitted passively by the body and measured in a "passive" channel. In the case of an opaque body, this allows the estimation of the emissivity of the body, and a temperature estimate based on Planck's law.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.