Computer simulation of low-pressure plasma discharges.

摘要

Inductively Coupled Plasma (ICP) reactors are being widely investigated for use in the creation of next-generation integrated circuits. This thesis focuses upon the development of a two-dimensional computer simulation of a cylindrically symmetric ICP discharge.;The first three moment equations of the Boltzmann equation are solved for electrons and each ion neutral species to yield spatial profiles of density, velocity, and temperature. Interactions between species pairs are determined by the appropriate collision integrals for the transfer of mass, momentum, and energy. Poisson's equation is solved to determine the electrostatic plasma potential. Reaction sets for argon and chlorine chemistries are presented.;Simulation predictions for a high density plasma operated with pulsed power input are examined. Such systems show promise for relieving defects seen in etched profiles at high density conditions. While the simulation is able to capture some of the plasma characteristics seen during the afterglow period of a pulsed plasma, the simulation assumption of a Maxwellian distribution of electron energies is probably not accurate well into the plasma decay.;Initial efforts at full validation of the simulation are undertaken with comparison to available measurements in a well-defined system, the Gaseous Electronics Conference Reference Cell (GECRC). Simulation predictions for argon and chlorine discharges are compared to experimental measurements of electron density and temperature, plasma potential, negative ion density, and neutral and ion temperature. Quantitative to qualitative agreement is found in most areas, with some areas of disagreement which suggest that some of the physical processes in the model are inadequate or incomplete.;Optical emission from a high-density flowing chlorine plasma is predicted from the simulation results, and is compared to experimental emission measurements. Good agreement between simulated and experimental emission profiles is found, but the simulation shows that the actual plasma structure may be far more complex than is indicated by simple emission profiles.