AVS 46th International Symposium
    Manufacturing Science and Technology Group Monday Sessions
       Session MS-MoM

Paper MS-MoM11
Simulations of Low Field Helicon Discharges@footnote 1@

Monday, October 25, 1999, 11:40 am, Room 611

Session: Advanced Design Methodologies and Factory Modeling
Presenter: R.L. Kinder, University of Illinois, Urbana
Authors: R.L. Kinder, University of Illinois, Urbana
M.J. Kushner, University of Illinois, Urbana
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Due to their high ionization efficiency, ability to deposit power within the volume of the plasma and ability to operate at low pressures, helicon reactors are attractive for downstream etching and deposition. The power coupling of the antenna radiation to the plasma is a concern due to issues related to process uniformity when using high magnetic fields (100s G to kG). Operating at low magnetic fields (< 100 G) is therefore preferred to provide more uniform ion fluxes and to reduce the cost of the tool. To investigate helicon operation over large ranges of magnetic fields a full tensor conductivity has been incorporated into the electromagnetics module of the Hybrid Plasma Equipment model (HPEM) augmented by an effective collison frequency to account for Landau damping. Plasma properties for helicon excitation of Ar, Ar/N@sub 2@ and process relevant gases (CF@sub 4@, C@sub 2@F@sub 6@) as a function of magnetic field strength, field configuration and power will be discussed. Results of an argon plasma excited by a m = 0 mode field operating at 13.65 MHz shows a resonant peak in the plasma density occuring in the low magnetic field range and is attributed to off-resonant cyclotron heating. The transition from inductive coupling to helicon mode appears to occur when the fraction of power deposited through radial and axial fields dominates. Results from HPEM-3D will be used to resolve helicon wave structure in the m = 1 and -1 modes. @FootnoteText@ @footnote 1@This work was supported by SRC, AFOSR/DARPA, Applied Materials and LAM Research.