Active solid-state devices (e.g. – transistors – solid-state diode – Bipolar transistor structure
Reexamination Certificate
2001-06-28
2002-11-19
Nelms, David (Department: 2822)
Active solid-state devices (e.g., transistors, solid-state diode
Bipolar transistor structure
C257S722000
Reexamination Certificate
active
06483169
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the packaging of integrated circuits and, more particularly, to an extruded heat spreader that reduces manufacturing costs and material consumption, and a method for making the same.
2. Description of Related Art
Packages for integrated circuits tend to generate substantial heat. This heat needs to be dissipated in order to ensure the operability of the circuits. A common method of removing heat is to employ a heat spreader. The heat spreader draws heat from the heat generating portions of the package and spreads it over an upper portion of the spreader. The upper portion is thermally coupled to a heat sink, or some other apparatus for dissipating heat. Conventional heat spreaders are fabricated using a stamping method. The stamping method bends or presses the metal blank into the desired end shape.
One such conventional heat spreader
10
is shown in FIG.
1
. Such a conventional heat spreader
10
has an upper portion
12
and sidewalls
14
that extend continuously from each edge of the upper portion
12
. Two pairs of flanges
16
extend from opposing sidewalls
14
to form a single flange
16
. The flange
16
also has an upwardly extending outer ridge
18
that occurs as a result of the stamping process. The conventional heat spreader is depicted in profile at
FIG. 1
a.
There are problems, however, with conventional heat spreaders. For example, in conventional heat spreaders, the flange extends continuously about the periphery of the heat spreader. Such a large flange, however, does not increase the ability of the heat spreader to spread heat over the spreader's upper surface for dissipation by the heat sink. The flanges therefore needlessly increase material consumption. Moreover, conventional heat spreaders are stamped, which requires that each individual heat spreader be formed one at a time. Thus, conventional heat spreaders tend to cause increased manufacturing costs as well as increased material consumption.
SUMMARY OF THE INVENTION
There is a need for a heat spreader, and a method for making the same, that can be produced more efficiently at a reduced manufacturing cost and with less material consumption, without reducing the effectiveness of the spreader.
These and other needs are met by embodiments of the present invention which provide an extruded heat spreader for a semiconductor device comprising an upper portion; first and second sidewalls only extending at respective first and second angles from opposite edges of the upper portion; and a pair of flanges extending at flange angles from the first and second sidewalls.
The extrusion process used to form the extruded heat spreader of the present invention reduces the amount of material needed to fabricate each heat spreader. Also, because there are only two sidewalls and two flanges, each heat spreader requires less material. As a result, manufacturing cost and material consumption are reduced.
The earlier stated needs are also met by another embodiment of the present invention which provides a method of fabricating a heat spreader for a semiconductor device, the method comprising providing a heat conducting material; extruding the material through a die; and cutting the extruded material into predetermined lengths to form a heat spreader having an upper portion; first and second sidewalls only extending at respective first and second angles from opposite edges of the upper portion; and a pair of flanges extending at flange angles from the first and second sidewalls.
Additional advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
REFERENCES:
patent: 5754402 (1998-05-01), Matsuzaki et al.
patent: 5930114 (1999-07-01), Kuzmin et al.
patent: 6114761 (2000-09-01), Mertol et al.
patent: 6118177 (2000-09-01), Lischner et al.
patent: 6191360 (2001-02-01), Tao et al.
patent: 6219238 (2001-04-01), Andros et al.
patent: 6219243 (2001-04-01), Ma et al.
patent: 6250127 (2001-06-01), Polese et al.
Alcid Edward S.
Tosaya Eric S.
Advanced Micro Devices , Inc.
McDermott & Will & Emery
Nelms David
Nguyen Thinh
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