Appeal No. 1998-2311
Application No. 08/401,869
According to the Examiner (Answer, page 8), Heinrich discloses
the claimed invention except for the use of a DC voltage to
bias the plasma chamber electrodes and the superimposition of
a DC voltage over an RF voltage to power the electrodes. To
address these deficiencies, the Examiner turns initially to
Walker which describes the biasing of electrodes 58 and 60 in
plasma chamber 12 in order to attract ions of a certain
polarity to the electrode of opposite polarity. O’Donnell is
added to the combination as providing a teaching of
superimposing a DC voltage over an RF voltage in the formation
of a plasma in a plasma apparatus. As stated by the Examiner
at pages 7 and 8 of the Answer:
Therefore, it would have been obvious to one of
ordinary skill in the art at the time the invention
was made to have formed a plasma between control
electrodes located at opposite sides of a chamber’s
longitudinal axis and provided a magnetic field to
control the electrons and ions in a plasma as taught
by Heinrich et al., to have utilized a DC voltage to
attract impurities out of a plasma and to have
superimposed a DC voltage over an RF voltage to an
electrode as taught by O’Donnell because it is
desired to form a plasma in a plasma apparatus.
In response, Appellants assert several arguments in
support of their position that the Examiner has not
established proper motivation for the proposed combination of
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