Appeal 2006-1454
Application 09/004,524
Patent 5,483,421
24. In the present invention, the chip carrier 24 preferably is made of the
same material as the circuit board 38 (col. 7, ll. 7-9).
25. If the chip carrier is not fashioned from the same material as the
board, it must, in any event, have a similar coefficient of thermal expansion; i.e.
the difference in the coefficient of thermal expansion between the carrier and the
circuit board should not vary more than about 20% (col. 7, ll. 9-13).
26. The chip carrier and board are made from an organic dielectric
material (col. 7, ll. 14-15).
27. In the preferred embodiment, the chip carrier and the board are both
made of glass filled epoxy FR-4 material which has a thermal coefficient of
expansion of about 17-20×10-6 ppm/C (col. 7, ll. 15-18).
28. The chip 20 is mounted to the chip carrier 24 by means of solder balls
36 which interconnect the I/O pads 22 on the chip 20 to the bonding pads 30 on the
top surface 26 of the chip carrier 24 (col. 7, ll. 47-50).
29. A circuit board 38 is provided which is preferably formed of the same
material as the chip carrier 24 or at least formed of a material that has a similar
coefficient of thermal expansion (col. 7, ll. 57-60).
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