Appeal No. 96-4180
Application No. 08/225,138
The invention relates to an improved ball grid array
integrated circuit package with high thermal conductivity.
Appellants disclose on page 7 of the specification that Figure
2B is a cross section illustration of an integrated circuit
package according to the preferred embodiment of the their
invention. On page 9 of the specification, Appellants
disclose an integrated circuit package having a substrate 16
having an opening disposed therethrough, a slug 14, formed of
a material with high thermal conductivity (such as copper),
having a bottom surface lying below the plane of the bottom of
the substrate 16 and a top surface that is stepped so as to
fit into the opening disposed in the substrate 16. Appellants
also disclose that the integrated circuit package has an
integrated circuit 12 attached to the top of the slug 14 and a
plurality of solder balls disposed between the bottom of the
substrate 16 and system circuit board 28. On page 11 of the
specification, Appellants disclose that the slug 14 serves as
a stand-off during solder reflow of the solder balls 24.
Appellants teach that the shape of the solder balls 24 after
reflow is determined in part by the collapse distance 26 as
shown in Figure 1A. This is the difference between the length
2
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