Effect of Plasma Heat flux on Cryogenic Substrate Temperature in an Inductive Discharge with RF bias power

The effect of plasma heat flux on the substrate temperature is investigated in an inductively coupled plasma with an RF-biased substrate. The substrate temperature is determined by liquid nitrogen cooling, plasma-generated heat flux, and the thermal conductivity of the gas. It is observed that the substrate temperature increases with increasing plasma heat flux. At 5 mTorr, When the bias power is increased from 0 W to 300 W, the substrate temperature increases by 40 °C. It is due to the ion heat flux as a result of the increased bias power. However, at 60 mTorr, although the ion heat flux increases, the substrate temperature increases less than at 5 mTorr. This is because the thermal conduction cooling increases due to more gas atoms striking the substrate at 60 mTorr. These show a relationship between plasma heat flux and substrate temperature.