AVS 46th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS-MoP

Paper PS-MoP8
Optical Emission and Mass Spectroscopic Studies of Reactive Species in an ICP Based Neutral Source for Ashing Processes

Monday, October 25, 1999, 5:30 pm, Room 4C

Session: Poster Session
Presenter: X.M. Tang, College of William and Mary
Authors: X.M. Tang, College of William and Mary
D.M. Manos, College of William and Mary
Correspondent: Click to Email
In this paper, we report measurements of particle composition and flux in downstream neutral cleaning processes in a reflection-neutral source, with a comparison to pulsed plasma processes. For Ar, O@sub 2@, and CF@sub 4@ mixtures, species in the both the plasma source and neutral process region are characterized by electrostatic probes, mass spectrometry, and optical emission; in the downstream region, calorimeter (energy) probes, and a micro-torsion (momentum) balance are used to discriminate the ion, photon, and neutral fluxes. The rf power, gas composition, reflector bias, discharge pressure have been varied in this study. The results show that in the downstream region, for Ar + O @sub 2@ plasmas, neutral O atom density and flux increase with increasing power from 100 to 500 watts, and also increase with increasing pressure. Ion species, including atomic and molecular ions, decrease in the downstream region as power and pressure increase over the same range. Both optical emission and mass spectral results show that the ratio of O/Ar increases sharply as the rf power increases above 200 watts in our source. In this source, neutral translational energy is varied by variation of the bias on the reflector plate. A concern in such a source has been that the variation of reflector bias may alter the species ratios in the source. The results of this study show that this is not the case. Using the combined diagnostic set, we have been able to differentiate the energy flux contributed by neutrals, photons, and charged particles striking the substrates. Our quantitative measurements indicate that the neutral flux is somewhat higher than predicted by our earlier simulations. This paper reports refinements to the model@footnote 1@ required to account for these new measurements. @FootnoteText@@footnote 1@ C.A. Nichols and D. M. Manos, J. Appl. Physics, vol.80 No.5 P2463.sept. 1996.