Abstract: A one-dimensional fluid model for RF methane plasma is presented.Equations of particle balance with drift-diffusion approximation for fluxes,and electron energy balance are solved.Totally 20 species(neutrals,radicals,ions,and electrons) are included in the model,as well as 49 reactions(27 electron reactions,7 ion-neutral reactions,and 15 neutral-neutral reactions).It is found that high electron reaction-rate occurs at high electric-field region.Besides inlet gas CH₄,neutral gases H₂,C₂H₆,C₃H₈,C₂H₄,and C₂H₂ also show high densities in the plasma.The main radical in plasma is CH₃,with a density of about 10¹⁹m^-3.At low pressures(e.g.,18Pa) the most important ion is CH₅⁺.At high pressures(e.g.,67Pa) C₂H₅⁺ becomes the dominant ion.Radical and ion fluxes towards electrode(except C₂H₅⁺) increase slightly with power.

Key words: methane plasma, radio-frequency discharge, fluid model, Boltzmann equation