Appeal No. 2004-0133
Application No. 09/668,031
a metallic layer deposited over the barrier layer
to form a solderable surface over the second surface of
the die;
a heat sink soldered to the metallic layer,
wherein solder material used to couple the metallic
layer to the heat sink provides good thermal
conductivity between the die and the heat sink.
In the rejection of the appealed claims, the examiner relies
on the following references:
Varteresian et al. (Varteresian) 4,499,659 Feb. 19, 1985
Lee 4,620,215 Oct. 28, 1986
Karnezos 5,843,808 Dec. 01, 1998
Appellants’ claimed invention is directed to semiconductor
packing arrangements and methods for forming such arrangements.
The claimed packaged integrated circuit comprises a die having
first and second surfaces with a multiplicity of die contacts on
the first surface. The second surface is provided with a heat
sink soldered to a metallic layer which, in turn is deposited
over a barrier layer formed on the second surface. According to
appellants’ specification, the claimed manner of securing the
heat sink to the second surface of the die is an improvement over
the prior art use of an epoxy adhesive. We are told that “[t]he
low thermal conductivity of the epoxy adhesive thus becomes a
significant limitation of the overall effectiveness of the heat
sink” (page 1 of specification, last sentence).
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