Appeal No. 1998-2311
Application No. 08/401,869
The disclosed invention relates to plasma processing and
the prevention of negative ions and negatively-charged
particulates from being trapped in the plasma. A particular
electrode and electrode-biasing configuration is provided in
which a formed plasma is maintained at a positive potential
with respect to a set of control electrodes placed at opposite
ends and aligned with a longitudinal axis of a plasma chamber.
A set of reference electrodes, positively biased with respect
to the plasma, are placed along opposing sides and aligned
with a lateral axis of the plasma chamber. A magnetic field
of a specified magnitude having magnetic field lines that
parallel the longitudinal axis of the plasma chamber is
provided enabling the negative ions and negatively charged
particles to laterally cross the magnetic field lines to the
more positively charged reference electrodes.
Claim 1 is illustrative of the invention and reads as
follows:
1. A method of controlling a plasma to prevent
negative ions and negatively-charged particulates from
becoming trapped within the plasma comprising the
steps of:
forming a plasma from a specified gas within a
plasma formation chamber, the chamber having control
2
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