Multi-parameter numerical investigation of inductively coupled plasma radial uniformity

In this study, we numerically investigate the key regulatory factors on the radial uniformity of inductively coupled plasma (ICP) sources. By employing a two-dimensional fluid model within the COMSOL Multiphysics software, we examine various configurations, including geometrical variations, gas pressure adjustments, substrate temperature, and coil modulation strategies. Our findings reveal that the chamber geometry and gas pressure significantly influence the radial distribution of plasma density. Notably, the radial temperature distribution of the substrate plays a non-negligible role: a linear temperature profile decreasing from 400 K at the center to 300 K at the edge remarkably improves plasma uniformity, while an increasing temperature profile exacerbates radial non-uniformity. In addition, adding solenoidal coils to the sidewall and independently controlling their power enhance local magnetic flux, generating high-density plasma through off-axis electron heating. When the power ratio of the top planar coil to the sidewall solenoid coil is set to 7:3, optimal uniformity is achieved. These results underscore the importance of deliberate design considerations for ICP sources aimed at enhancing plasma uniformity and offer practical guidance for industrial applications, such as plasma etching.