Patent ID: 8388219

Claim:
Method for calibrating a pyrometer ( 1 ) adapted to intercept and measure thermal radiation, wherein at least one measured thermal radiation signal is assigned with a temperature value, the method comprising: providing a calibration sample ( 12 ), wherein the calibration sample ( 12 ) comprises a semiconducting wafer ( 2 ) and a transparent calibration layer ( 13 ) disposed on the semiconducting wafer ( 2 ), heating the calibration sample ( 12 ), during the heating process: irradiating a first optical radiation having a first wavelength onto the calibration sample ( 12 ), measuring a first reflection signal resulting from reflection of the first radiation on the calibration sample ( 12 ), and determining a first reflectance of the calibration sample ( 12 ) for the first wavelength from the measured first reflection signal, irradiating a second optical radiation having a second wavelength onto the calibration sample ( 12 ), the first wavelength and the second wavelength being different from each other, measuring a second reflection signal resulting from reflection of the second radiation on the calibration sample ( 12 ), and determining a second reflectance of the calibration sample ( 12 ) for the second wavelength from the measured second reflection signal, and measuring, by the pyrometer ( 1 ), a thermal radiation signal received from the calibration sample ( 12 ), wherein a temperature of the calibration sample ( 12 ) is determined from the ratio of the first reflectance and the second reflectance and wherein the pyrometer ( 1 ) is calibrated by assigning the determined temperature of the calibration sample ( 12 ) with the thermal radiation signal measured by the pyrometer ( 1 ).