Apparatus and method for compensating for errors in temperature measurement of semiconductor wafers during rapid thermal processing

An apparatus for calibrating a processing signal derived from characteristics of a semiconductor wafer, comprising:

• a processing chamber having a range of temperature settings including means for holding a calibration wafer;
• temperature measurement means coupled to the processing chamber for transmitting a signal indicating the temperature of said calibration wafer;
• light emission measurement means coupled to said processing chamber for measuring an amount of light emitted by said calibration wafer;
• light emission means for providing light to be reflected off of a sample batch wafer and said calibration wafer;
• reflection measurement means for measuring the intensity of said light reflected off of said sample batch wafer and said calibration wafer and providing a reflection signal;
• and
• computer means for recording the amount of light emitted and temperature of said calibration wafer connected to the temperature measurement and light emission measurement means, including memory means for storing a first calibration table constructed from measured light emission and temperature values used to determine a level of the processing signal, the computer means being programmed to recall and modify the first calibration table in accordance with a difference in said reflection signal for said sample batch and calibration wafer to generate a second calibration table and to calibrate said processing signal based on said entries of said second calibration table.

An apparatus for calibrating a processing signal derived from characteristics of a semiconductor wafer, comprising:

• a processing chamber including means for holding said wafer;
• a long arc lamp for heating said processing chamber to a range of temperature;
• a power supply for said long arc lamp;
• temperature measurement means coupled to the processing chamber for transmitting a signal from a thermocouple attached to a calibration wafer for indicating the temperature of the calibration wafer;
• a first infrared pyrometer coupled to said processing chamber for measuring an amount of light emitted by the calibration wafer;
• light emission means mounted outside said processing chamber for providing infrared light to be reflected off a particular wafer;
• a second infrared pyrometer mounted outside said processing chamber for measuring the intensity of said light reflected off of said particular wafer and providing a reflection signal;
• a transfer arm for loading said particular wafer into said processing chamber and passing said particular wafer over said light emission means and said second infrared pyrometer;
• and
• computer means for recording the amount of light emitted and temperature of the calibration wafer connected to the temperature measurement and light emission measurement means, including memory means for storing a first calibration table constructed from the measured light emission and temperature values used to determine a level of the processing signal, the computer means being programmed to recall and modify entries of said first calibration table according to light emission values of a sample batch wafer as measured by the first pyrometer to generate a second calibration table, said computer means being programmed to modify a light emission value from said second pyrometer with said second calibration table and to provide a modified signal as a control signal to said power supply for said processing chamber, said computer means also being programmed to modify said second calibration table in accordance with a difference in said reflection signal between a batch wafer and one of said sample batch and calibration wafers to generate a third calibration table and to calibrate said processing signal based on said entries of said third calibration table.