Method for measuring surface temperature of semiconductor wafer substrate, and heat-treating apparatus

An apparatus for heat-treating a semiconductor wafer substrate, comprising:

• means for heating the wafer substrate;
• means for intermittently emitting infrared rayincluding reference light toward the wafer substrate;
• means for selectively detecting infrared rays of a plurality of kinds whose wavelengths are differ from each other, among the infrared rays included in the reference light;
• means for detecting infrared rays having the same wavelengths as those of the selectively detected infrared rays, among the infrared rays included in the reference light reflected by the wafer substrate and the infrared rays radiated by the wafer substrate itself;
• means for discriminating the infrared rays included in the reference light reflected by the wafer substrate from the infrared rays radiated by the wafer substrate itself;
• means for calculating the surface temperature of the wafer substrate on the basis of the selectively detected infrared rays, the discriminated infrared rays included in the reflected reference light, and the discriminated infrared rays radiated by the wafer substrate;
• and
• means for controlling the heating means on the basis of the calculated surface temperature.

An apparatus for heat-treating a semiconductor wafer substrate, comprising:

• means for emitting light toward the wafer substrate;
• means for measuring the temperature of the wafer substrate on the basis of light coming from the wafer substrate with taking change of emissivity of the wafer substrate into consideration;
• and
• means for controlling the heating means in accordance with the temperature measured by the measuring means.