Rapid measurement of substrate temperatures by frequency-domain low-coherence interferometry

摘要

Rapid high-precision temperature monitoring systems for silicon wafers applicable even during plasma processing have been developed using frequency-domain low-coherence interferometry without a reference mirror. It was found to have a precision of 0.04 ℃, a response time of 1 ms, and a large tolerance to mechanical vibrations and fiber vending when monitoring the temperature of commercial Si wafers. The performance is a substantial improvement over the previous precision of 0.11 ℃ measured in a few seconds using a time-domain method. It is, therefore, a powerful real-time technique to monitor rapidly varying wafer temperatures with high precision.