Parallel Fluid Modeling of Low-Pressure Electro-positive and Electro-negative Gas Discharges Considering Full Ion Momentum Equations
Kuan-Lin Chen1, Meng-Fan Tseng1, Bi-Ren Gu1, Jong-Shinn Wu1*
1Department of Mechanical Engineering, National Chiao Tung University, Hsinchu, Taiwan
* presenting author:JONG-SHINN WU, email:chongsin@faculty.nctu.edu.tw
To help the design of advanced plasma source, fluid modeling is one of the most powerful modeling techniques in treating realistic low-pressure gas discharges driven by high frequency power source. The plasma fluid modeling solves a set of velocity moment equations derived from the Boltzmann equation, include continuity, momentum, energy density equations. For electrons, it is highly justified to use drift-diffusion approximation to simplify the momentum equation, if the frequency of the driven power source is less than GHz level. However, most previous studies employed the drift-diffusion approximation for ions to simplify momentum equations, which is problematic since the ions are generally heavy. Thus, consideration of the inertia effect of the heavy ions through inclusion of full ion momentum equations is necessary to accurately model the low pressure gas discharge. In this study, we have solved the full ion momentum equations in our fluid model, in addition to continuity, energy and Poisson equations. Parallel computing using domain decomposition is employed reduced the computational time. Two typical examples including electro-positive (argon) and electro-negative (CF4) gas discharge will be presented for 1D and 2D-axisymmetric configuration. For the electro-negative case, a special technique in damping the numerical instability is proposed, which is otherwise difficult to obtain a stable solution. More details will be presented in the meeting.


Keywords: plasma, etching, fluid model