Modulation effect of the plasma radial uniformity in dual-frequency inductively coupled plasma by external magnetic field

In recent years, dual-frequency inductively coupled plasma (DF-ICP) has proven to be a reliable technique for enhancing plasma radial uniformity. In this paper, a fluid model is employed to study the effects of low frequency (LF), low-frequency coil (LFC) current, and magnetic field coil (MFC) current on the plasma characteristics and radial uniformity of magnetized DF-ICP. The simulation results show that when the cyclotron frequency is consistent with the radio frequency, the electrons in cyclotron motion gain a lot of energy from the background electric field, resulting in a significant increase in the electron power absorption rate, ionization rate, and electron density. At this point, the electron cyclotron resonance occurs in the system. In addition, the effect of LF on the plasma is negligible due to its small growth amplitude (i.e., from 2 to 6.78 kHz). In the strong magnetization stage, as the MFC current increases, the plasma density shifts from chamber center to edge, and the radial uniformity first increases and then decreases. This can be attributed to the enhanced strong magnetic confinement effect, the smaller electron cyclotron radius, and the contribution of the reversal electric field. In addition, it is observed that adjusting the LFC current can cause electric field reversal to occur earlier or later. The results show that the LFC current can effectively suppress the magnetization effect of the external magnetic field on the plasma.