Appeal No. 1998-1850
Application No. 08/596,613
paragraph of column 5 of the reference to be inconsistent with the conclusion of
obviousness of the claimed subject matter. Even if, as appellants further allege, the
column 5 section refers to non-disclosed ion implantation such as that taught by
Tsunohara, Havemann strongest statement is simply that “layer 30 may require thinning
after implantation to reduce the aspect ratio of insulated gap 29.” See Havemann, column
5, lines 2-15. Havemann does not teach to what degree the aspect ratio may need to be
reduced. Presumably very little, as there would only be stray ions embedded in the surface
of layer 30, assuming that the “implantation” refers to ion implantation as disclosed by
appellants or by Tsunohara. The ions would be directed parallel to layer 30, which is “on
the sidewalls of conductors 26.”
In any event, Tsunohara discloses an aspect ratio of 5, and the prior art as
represented by each of Havemann and Tsunohara recognized that higher aspect ratios
were desirable. The claim 1 recitation of “an aspect ratio greater than about 4 to 1" does
not take the subject matter out of the realm of prima facie obviousness. The artisan would
have been expected to at least experiment with finding the upper limits of practical aspect
ratios. “We start from the self-evident proposition that mankind, in particular, inventors,
strive to improve that which already exists.” Pro-Mold & Tool Co. v. Great Lakes Plastics,
Inc., 75 F.3d 1568, 1573, 37 USPQ2d 1626, 1630-31 (Fed. Cir. 1996). Appellants have
provided no evidence to establish that a practical limit exists that is something less than
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