Effect of gas flow on RF plasmas

Effects of gas flow on rf plasmas between parallel plates under plasma proc essing conditions are investigated using a Monte Carlo simulation (MCS) and a fluid model calculation. It has shown that the gas now changes the ion d ensity distribution in the bulk legion of the rf plasma where the velocity of gas flow is faster than that of the ion diffusion motion. Comparison of the results of the MCS with those of the fluid model calculation has shown that the fluid model in which the velocity of gas now is added to the drift and diffusion motion may be valid at a pressure above 1 Torr. Using the fl uid model and Poisson's equation, self-consistent calculations of the argon and silane rf plasmas have been carried out. This indicates chat the plasm a structure including negative ions is sensitively changed by the gas flow.