Appeal No. 1997-3390
Application No. 08/354,384
2, molybdenum or tungsten layer 18, having a thermal
coefficient of expansion similar to that of semiconductor
wafer, is flame sprayed onto the back side of semiconductor
die 12. Appellants further disclose that metal layer 15 may
be optionally deposited on the back surface of the die before
depositing the heat spreading layer for improved adhesion or
contact resistance. The step of flame spraying which is
performed in less than a minute at a temperature below 200EC,
as disclosed on page 6 of the specification, minimizes damage
to the active regions with electrical properties that can be
adversely affected by extended exposure to high temperature.
Additionally, Appellants disclose on page 6 of the
specification that the semiconductor die with the flame
sprayed metallization layer is attached to a metal substrate
using low melting point solders.
Representative independent claim 8 is reproduced as
follows:
8. A method for fabricating a
semiconductor device with a flame sprayed heat
spreading layer comprising the steps of:
providing a semiconductor die having a
thermal coefficient of expansion and a back
surface;
providing a material having a thermal
coefficient of expansion similar to the
2
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