Presentation Information
[22p-12G-8]Real-time Temperature Measurement of Silicon Wafer Surface Under Plasma Irradiation using Optical-Interference Contactless Thermometry (OICT)
〇(M1)Ryunosuke Goto1, Hiroaki Hanafusa1, Higashi Seiichiro1 (1.Hiroshima Univ.)
Keywords:
plasma process,cryo etching,surface temperture
In plasma processes, real-time measurement of wafer surface temperature is very important for process control. It has been reported that the wafer surface temperature has a significant effect on the etching rate, especially in the case of cryo-etching in which the wafer temperature is lowered to around -60°C. However, it is difficult to measure the wafer temperature from the wafer surface side due to the plasma. However, it is difficult to measure the temperature from the front side of the wafer due to the plasma, and it is difficult to estimate the surface temperature accurately from the back side due to the temperature gradient caused by the heat input from the plasma and the cooling of the backside of the wafer, respectively. We have developed an optical interference non-contact temperature measurement technique (OICT) based on the principle that a laser beam is irradiated from the backside of a wafer and the reflected light interferes with the wafer as its temperature changes, and have reported a technique for measuring the surface temperature from the backside of a wafer. In this study, we have improved the analysis method of OICT to measure the surface temperature of silicon wafers in real time during the plasma process.