Integrated circuit device package and heat dissipation device

Details Integrated circuit device package and heat dissipation device Integrated circuit device package and heat dissipation device

2000-09-14

2001-11-13

Picard, Leo P. (Department: 2835)

Electricity: electrical systems and devices

Housing or mounting assemblies with diverse electrical...

For electronic systems and devices

C361S699000, C361S690000, C361S698000, C361S717000, C165S080400, C257S712000, C257S713000, C257S714000, C257S721000, C257S722000, C174S015100, C174S016300

Reexamination Certificate

active

06317326

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to heat dissipation of an integrated circuit device, in particular, to integrating an integrated circuit device package with a heat dissipation device.
BACKGROUND OF THE INVENTION
Integrated circuitry fabricated on semiconductor chips generates heat during normal operation. If the heat generated becomes excessive or the heat generated is not effectively removed, the integrated circuit device can malfunction or fail. In other words, the reliability of the integrated circuit device may be compromised if the integrated circuit device overheats. There are many ways to remove heat from an integrated circuit device, for example, by placing the integrated circuit device in a cool spot in the enclosure or using a liquid-cooled plate connected to a refrigerated water chiller. In general, the amount of heat generated by the integrated circuit device, the integrated circuit device package configuration and the expected lifetime of the product combine with many other factors determine the optimum heat removal scheme.
The interface between the integrated circuit device and the heat dissipation device used to cool the integrated circuit device may be a factor in designing a thermal solution. More specifically, microscopic air gaps (e.g., caused by surface non-uniformity) between an integrated circuit device package and a heat sink attached to the integrated circuit device package's surface may affect or degrade thermal performance. Typically, the degradation in thermal performance increases as the operating temperature increases. The surface variability induced by varying surface roughness may be reduced by using interface materials appropriate to the package type. However, it is difficult, if not impossible, to completely eliminate the surface variability.
The development of faster and denser circuit technologies and smaller packages which are accompanied by increasing heat fluxes at the chip and package levels complicate the problem. Although significant advances have been made in air cooling techniques to manage increased heat fluxes, it has long been recognized that significantly higher heat fluxes are better accommodated through the use of liquid cooling.
FIG. 1
shows an electronic device
100
having a cavity-up design. A flip-chip
106
is bonded to a substrate
102
via flip-chip bumps
108
. A lid
110
, which can be multi-component or one component is attached to substrate
102
via adhesive
112
. Lid
110
provides mechanical structure strength to the device. A cold plate
116
is attached to lid
110
with an adhesive
120
.
Cold plate
116
is constructed of a cap
116
a
and a base
116
b
. Base
116
b
includes fins
116
c
and cap
116
a
includes an inlet
122
and an outlet
124
. Cap
116
a
is attached to base
116
b
through an adhesive
121
, forming channels
116
d
. Electronic device
100
may be coupled to a printed circuit board (PCB) via Ball Grid Array (BGA) balls
104
.
In
FIG. 1
, the thermal path for dissipating heat generated by flip-chip
106
includes adhesive
114
, lid
110
and adhesive
120
. Each junction/interface (e.g., between flip-chip
106
and lid
110
, between lid
110
and cold plate
116
) causes a junction temperature which is undesirable because junction temperatures increase the impedance of the thermal path, thus decrease thermal dissipation efficiency.
In some instances, where thermal requirements cannot be met with the added junction temperature caused by the adhesive between the lid and the adhesives, the lid may be eliminated all together and a cold plate directly attached to the silicon substrate. Although the resulting structure eliminates the junction temperature caused by the lid, the elimination of the lid also eliminates the mechanical strength provided by the lid, resulting in a weak structure.
SUMMARY OF THE INVENTION
The invention relates to methods and apparatus to increase heat dissipation of an integrated circuit device while retaining mechanical strength of the integrated circuit device.
In accordance with the invention, an integrated circuit device package is integrated with a heat dissipation member to reduce the number of junctions in the packaged integrated circuit device. In one embodiment of the present invention, the integrated circuit device package includes a substrate, a semiconductor chip mounted on a first surface of the substrate, and a thermally conductive lid integrated with a first heat dissipation member coupled to the first surface of the substrate, thereby forming a closed cavity between the thermally conductive lid and the substrate. The semiconductor chip is enclosed in the closed cavity.
In one embodiment, the integrated circuit device package includes a second heat dissipation member which is coupled between the thermally conductive lid and the first heat dissipation member. In one embodiment, the second heat dissipation member and the thermally conductive lid form at least one thermal interface gap at a location corresponding to the amount of heat dissipation of the semiconductor chip.
This summary is not intended to limit the scope of the invention, which is defined solely by the claims attached hereto.


REFERENCES:
patent: 5268814 (1993-12-01), Yakubowski
patent: 5285351 (1994-02-01), Ikeda
patent: 5291064 (1994-03-01), Kurokawa
patent: 5345107 (1994-09-01), Daikoku et al.
patent: 5528456 (1996-06-01), Takahashi
patent: 5705850 (1998-01-01), Ashiwake et al.
patent: 5880524 (1999-03-01), Xie
patent: 5923086 (1999-07-01), Winer et al.
patent: 0 447 835 A2 (1991-09-01), None

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