Appeal No. 2005-2276
Application No. 09/734,467
making the combination. See Lindemann Maschinenfabrik GMBH v. American Hoist and
Derrick Company et al., 730 F. 2d 1452, 1462, 221 USPQ 481, 488 (Fed. Cir. 1984). With this
precedent in mind, we turn to the examiner’s section 103 rejections. We are unconvinced that
the applied prior art as a whole would have suggested the combination as proposed by the
examiner.
The examiner believes an artisan would have been motivated to combine Kawakubo and
Azuma “in order to form a bottom electrode that adheres well to the underlying layers” (answer,
page 5). However, Kawakubo does not disclose any adherence problem between the electrode
and the underlying layers. The appellants have correctly argued that Kawakubo uses a Pt-Ti
alloy for the electrode and thus already provides good adherence between the bottom electrode
and the underlying layers. That is, titanium (which is used in Kawakubo’s electrode) is known to
adhere well to precious metal layers (e.g., platinum which is also used in Kawakubo electrode)
and to underlying layers (see Azuma, column 1, lines 27-37). Therefore, an artisan would not
have been motivated to modify Kawakubo in the above quoted manner for the purpose of
improving adherence of the electrode as stated by the examiner.
In regard to avoiding surface irregularities as a basis for motivation, Kawakubo teaches
that “metal flow” (i.e., surface irregularities) happens during chemical-mechanical polishing
(CMP) when soft noble metals are used in forming the bottom electrode (see the paragraph
bridging columns 5 and 6). To solve this problem, Kawakubo employs an alloy of noble metal
and additive elements such as titanium to make the metal harder, so that the CMP will not
damage the harder alloy (col. 6, lines 7-14). On the other hand, Azuma discloses that cracking,
peeling and surface irregularity problems occur because of different thermal expansion
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