Three-dimensional simulation of inductively coupled plasma reactors

Modeling and simulation of plasma reactors can help in the design, scale-up and optimization of new tools used in advanced microelectronic device fabrication. MPRES, or Modular Plasma Reactor Simulator, is a finite element self-consistent fluid simulation code for inductively coupled plasma reactors. A two-dimensional version of the code was tested against experimental data taken at Applied Materials Inc. in chlorine and argon plasmas. Simulation results of electron density and temperature as a function of pressure, power and gas flow rate, as well as ion flux uniformity, were in good agreement with experimental measurements for both gases.; The code was then extended to three dimensions to address azimuthal asymmetries associated with gas inlets, pumping ports, and non-uniform power deposition in the plasma. Gas inlets were found to introduce only local asymmetries that do not persist to the wafer level for the reactor geometry and the operating conditions under consideration. On contrary, the pumping port introduces significant azimuthal asymmetries affecting the ion and neutral fluxes on the wafer. The use of a focus ring was found to be beneficial reducing the pumping port effect and resulting in azimuthally more uniform profiles.; The effect of the nonuniform power deposition was also examined using MPRES-3D. Due to current losses along the induction coil, the current density is not uniform and the power is deposited in a nonuniform toroidal zone in plasma. A peak in the power deposition zone was observed at the same azimuth as that of the maximum current density in the coil. Plasma species density was affected by the nonuniform power and a peak in etching rate was evident because of the power deposition peak near the top of the reactor. The effect of nonuniform power deposition was found to be more important than the pumping port effect for the reactor and the conditions used in this work.; Finally, a one-dimensional model was also developed describing the spatiotemporal structure of the sheath and the ion energy distribution (IED) at the electrode of a collisionless electropositive glow discharge for arbitrary radio frequencies (rf).