Presentation Information
[23p-A301-5]Real-time measurement of silicon wafer surface temperature during plasma process using Optical-Interference Contactless Thermometry(OICT)
〇Ryunosuke Goto1, Hiroaki Hanafusa1, Seiichiro Higashi1 (1.Graduate School of Advanced Science and Engineering, Hiroshima University)
Keywords:
silicon,temperature measurement,plasma
In the plasma process, it is very important to measure the wafer surface temperature in real time for process control. We have developed an Optical-Interference Contactless Thermometry (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. Furthermore, we have developed a high-speed temperature analysis program(ZG method) to directly determine the wafer surface temperature from the interference waveform, and reported that the analysis time can be reduced from several hours to within one second. However, when there is a temperature gradient from the wafer surface to the backside, the ZG method cannot accurately reproduce the surface temperature. In this study, we developed a program that can analyze the wafer surface temperature accurately and quickly even under heating conditions where temperature gradients occur, by extracting features from the waveform and referring to the conditions that match the features from the database.