Two-Dimension Fluid Simulations Of Inductively Coupled Ar And Ar/O₂ Discharges

Radio Frequency Inductively Coupled Plasma (RF-ICP) sources are widely used in semiconductor fabrication for etching and deposition of thin films due to the high plasma density at low gas pressures, as well as the relative simplicity. In the actual process, the plasma distribution is mainly determined by external factors, such as power source parameters, chamber geometry, and working gas properties. Therefore, it is very important to have a good insight into the plasma characteristics under various conditions, as this accordingly affects the etching and deposition processes.In this dissertation, a two-dimensional fluid model has been used to investigate the plasma characteristics in argon planar coil inductively coupled discharges. Special attention has been paid to the effects of the source power, the pressure, as well as the gas ratio on the plasma properties, especially on the electron density, ion density and electron temperature. Moreover, the physical mechanisms of the discharge process have also been demonstrated. By comparing with the results obtained by COMSOL Multiphysics software, a good agreement is achieved. Indeed, the electron density increases linearly with gas pressure and power, whereas the electron temperature and plasma potential show different behaviors. They decrease with pressure, and almost remain constant with power.In addition, the fluid model has been employed to study the plasma characteristics in Ar/O2 discharges. The emphasis has been put on the influence of the external parameters, such as the RF power, the pressure and the Ar/02 gas ratio, on the plasma spatial distribution and on the electronegativity. The numerical results show that the RF power has a more significant influence on the absolute value of the plasma properties rather than on the spatial distribution. However, the pressure and the Ar/O2 gas ratio affect not only the peak value, but also the spatial uniformity. Finally, the comparison between the experimental data and the simulation results obtained by our model and COMSOL has been made at different gas pressures and oxygen contents, and a good agreement is achieved.