Abstract: Radiant energy from a semiconductor wafer which is determined from the theoretical value of black body radiation and the actually measured result of an output from a photodiode are brought into correspondence with each other, and a table showing a correlation therebetween is acquired and stored on a magnetic disk. When a semiconductor wafer to be treated is irradiated with flashes of light from flash lamps, the photodiode receives radiant light emitted from the semiconductor wafer. A controller determines, from the output from the photodiode, the radiant energy emitted per unit time from the semiconductor wafer irradiated with flashes of light, based on the acquired table. The controller further determines the surface temperature of the semiconductor wafer from the determined radiant energy.

Abstract: Radiant energy from a semiconductor wafer which is determined from the theoretical value of black body radiation and the actually measured result of an output from a photodiode are brought into correspondence with each other, and a table showing a correlation therebetween is acquired and stored on a magnetic disk. When a semiconductor wafer to be treated is irradiated with flashes of light from flash lamps, the photodiode receives radiant light emitted from the semiconductor wafer. A controller determines, from the output from the photodiode, the radiant energy emitted per unit time from the semiconductor wafer irradiated with flashes of light, based on the acquired table. The controller further determines the surface temperature of the semiconductor wafer from the determined radiant energy.