Investigation of Neutral Gas Heating Effects in an Inductively Coupled Ar/C₄F₈ Plasma

Low-temperature fluorocarbon plasmas are widely utilized in material processing, particularly in reactive ion etching (RIE). Accurate modeling of neutral species transport and thermal behavior is essential for process optimization. In this study, a two-dimensional axisymmetric fluid model of an inductively coupled Ar/ C₄F₈ plasma was developed to investigate the influence of neutral collisional enthalpy changes on gas heating and overall plasma dynamics. The model incorporates heat transfer and Navier–Stokes equations to resolve spatial variations in neutral gas temperature, addressing limitations of conventional isothermal plasma models. Parametric studies were performed by varying input power (200–600 W), pressure (20–60 mTorr), and Ar : C₄F₈ gas ratios (0.2–0.5). Simulation results indicate that gas heating driven by neutral collisions significantly alters plasma behavior. These findings were validated against experimental radical density measurements using quadrupole mass spectrometry (QMS) under various process conditions. The results show that incorporating thermal effects into plasma modeling enables more accurate predictions of the etching process.