Evaluating power deposition in Inductively Coupled Plasma systems using the particle-in-cell code VSim

Inductively Coupled Plasma (ICP) sources are a crucial technology for materials processing, particularly in the semiconductor industry [1]. These plasma chambers are characterized by an external antenna, typically driven by an RF current source. Power is electromagnetically coupled into the system where the plasma is sustained primarily by ohmic heating of electrons and electron-impact collisions. ICPs generally operate at 10s of mTorr and can generate plasma densities up to 1×1018 m-3 even at low pressure. Simulations of ICPs have been extensively done, typically using fluid-based models [2], which do not account for non-local heating. At lower pressures, a fully-kinetic approach is necessary to correctly capture the discharge physics.

This work analyzes power deposition in ICP processing chambers using the VSim particle-in-cell code [3,4]. Modeling the high density plasmas generated in these systems is made tractable by using a 2D cylindrical simulation domain with a novel implicit solve to model the antenna. The simulation geometry chosen for this work is based on the Gaseous Electronics Conference reference cell operating in the ICP configuration with an He plasma discharge at 1-20 mTorr. Comparisons with other models will be made, and the conditions necessitating a fully-kinetic treatment of the plasma will be discussed.

[1] M. A. Lieberman and A. J. Lichtenberg, Principles of Plasma Discharges and Materials Processing, John Wiley & Sons, Inc. (2005).

[2] M. J. Kushner, J. Phys. D. Appl. Phys. 42, 194013 (2009).

[3] C. Nieter and J. R. Cary, J. Comp. Phys. 196, 448 (2004).

[4] www.txcorp.com/vsim