Appeal 2007-2342
Application 10/884,654
an electronics package, where the substrate has a function similar to the
interposer. A “gap” is formed on the substrate (2) underside when metal (1)
is etched, leaving a hollow space surrounded by “pillar-like interconnections
(11)” in the unetched regions (Wakashima, [0042]). The hollow is filled in
with a resin base 4 to increase its mechanical strength (Wakashima, [0043]).
“The thickness of the pillar-like interconnection 11 is 12 µm to 100 µm. . . .
If the thickness of the interconnection 11 is less than 12 µm, the resin base 4
also becomes thin, and the mechanical strength of the substrate decreases. In
addition, the insulating ability of the resin base 4 deteriorates” (Wakashima
[0031]).
Thus, Wakashima teaches that etching the metal to produce a hollow
region between pillar-like interconnections reduces the thickness of the
substrate/metal in the etched region, decreasing its mechanical strength and
insulating ability. Persons of skill in the art would have recognized this is
the same defect that occurs in the prior art electronics package when the
interposer is hollowed to accommodate the pin carrier.1 Whether this region
is characterized as a “cavity” or a “gap,” is not dispositive since in each case
there is a hollow region having a thin ceiling (substrate or interposer) of
reduced mechanical strength. Wakashima teaches filling it with a resin to
“guarantee” its mechanical strength (Wakashima, [0043]). We agree with
the Examiner that this constitutes a strong teaching that package strength can
be increased by filling hollow spaces with resin, prompting the skilled
worker to have modified the admitted prior art electronics package.
1 It also appears that Appellant admits that the thin interposer of the prior art
package was known to be a problem because of its reduced mechanical
strength (Spec. 2: 25-27; 3: 20-25).
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Last modified: September 9, 2013