| 摘要 |
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. |
