Three-dimensional Simulation Of Inductively Coupled Plasma Discharge Characteristics

Inductively coupled plasma (ICP) source has the following advantages:1. It has high energy coupling efficiency, and a high density plasma can be obtained by it at low pressure and low power.2. It can control the plasma density and the ion energy bombarding on the substrate independently. Therefore, it has been widely used in semiconductor manufacturing. In addition, in the neutral beam injection system, which is the mainly method for plasma heating in the magnetic confinement fusion, the ICP source is also chosen as the ion source. Based on the very important application prospect of ICP source, it is very necessary to study the characteristics of ICP discharge in detail. The purpose of this paper is to study the influence of the discharge parameters such as deposition power, discharge pressure, radius of coil and magnetic field on plasma characteristics (electron density, electron temperature, and s ion density, etc.), and expect the simulation results can play a role on the design of ICP chamber structure.A fluid model is built to study the inductively coupled plasma discharge process in a cylindrical coil configuration and the COMSOL Multiphysics software is used to present three-dimensional simulations on the hydrogen plasmas.Due to that the calculation of three-dimensional simulations is very time consuming, in our simulations, we try to use coarser grids. By comparing the results of three-dimensional simulation with coarser grid to the results of two-dimensional simulation with fine grids for the same axisymmetric discharge example, we can find that both the results are consistent quantitatively in a wide range of pressure and power. Therefore, the three-dimensional simulations on discharge with coarser grids are reliable.With the three-dimensional simulations, the cusped magnetic field effects on inductively coupled plasma discharge characteristics is mainly studied. The results indicate that with the increase of magnetic induction intensity, the density of plasma (including the electron density, the ion density and the density of radicals) increase gradually, but the temperature of electrons decreases gradually. And cusped magnetic field have a certain effect on the spatial distribution of plasma. In addition, under the condition of the magnetic field is constant, the increase of pressure weakens the role of magnetic field, Finally, the influence of coil radius on the plasma discharge is discussed. The simulation results show that as the coil radius increases the density of plasma decreases significantly.