Appeal No. 2006-0291
Application No. 09/820,692
Liu et al. (Liu) 6,451,703 B1 Sep. 17, 2002
(filed Mar. 10, 2000)
Demmin et al. (Demmin) 6,635,185 B2 Oct. 21, 2003
(filed Dec. 31, 1997)
The claims on appeal stand rejected under 35 U.S.C. § 103(a) as unpatentable
over Liu in view of Schmitt, as also evidenced by Demmin, Tahara, and Loewenstein
(Answer, page 3). Based on the totality of the record, we affirm the rejection on appeal
essentially for the reasons stated in the Answer, as well as those reasons set forth
below.
OPINION
The examiner finds that Liu discloses a method of etching a dielectric layer with
selectivity to an underlying stop layer where the semiconductor substrate is supported in
a plasma etch reactor, with an etchant gas of a hydrogen-free fluorocarbon being
supplied to the plasma etch chamber through a showerhead at pressures between 25
millitorr (mT) and 70 mT (Answer, pages 3-4). The examiner further finds that Liu
teaches use of a capacitively coupled plasma reactor including an upper showerhead
electrode and a bottom electrode (a magnetically enhanced reactive ion etch (MERIE)
plasma reactor)(id.). The examiner finds that Liu differs from the claimed invention by
not specifying a “dual frequency” capacitively coupled plasma reactor (Answer, page 4).
Therefore, the examiner applies Schmitt as evidence that a dual frequency capacitively
coupled plasma reactor, including an upper showerhead electrode and a bottom
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