In situ Si Wafer Surface Temperature Measurement during Flash Lamp annealing

摘要

Automatic emissivity compensating radiation thermometry based on polaradiometry was applied to in situ wafer surface temperature measurement on a flash lamp annealing prototype system. The developed temperature measurement system consists of a dual polarization radiation thermometer and a modulating reference light source, which were mounted on two opposing ports of the process chamber. The intense background radiation from the flash lamp was successfully suppressed by introducing a water flow layer beneath the flash lamp unit and measuring at the water absorption band of 1.95 μm. Millisecond heating and cooling of the wafer was measured for various operating conditions of the flash lamp and for various silicon wafers including wafers with microstructures. The peak temperature was compared with the sheet resistance after treatment and device properties after fabrication. Good correlation was confirmed between sheet resistance and measured peak temperature for various flash lamp intensities irrespective of the surface emissivity or heating conditions. Transistor threshold voltage showed similar correlation, which verifies the applicability of the developed thermometer system to in situ measurement during production.