U.S. patent application number 09/432578 was filed with the patent office on 2002-05-16 for heatpipesink having integrated heat pipe and heat sink.
Invention is credited to BROWNELL, MICHAEL PHILIP, MAVEETY, JAMES G..
Application Number | 20020056908 09/432578 |
Document ID | / |
Family ID | 23716744 |
Filed Date | 2002-05-16 |
United States Patent
Application |
20020056908 |
Kind Code |
A1 |
BROWNELL, MICHAEL PHILIP ;
et al. |
May 16, 2002 |
HEATPIPESINK HAVING INTEGRATED HEAT PIPE AND HEAT SINK
Abstract
Embodiments of the present invention can dissipate heat and
include a top wall including a plurality of hollow fins, a bottom
wall, and a plurality of side walls that define an inner cavity. A
plurality of condenser regions can be located within the inner
cavity, and each one of the plurality of condenser regions can be
located within one of the plurality of hollow fins. The inner
cavity also can include an evaporator region adjacent said bottom
wall.
Inventors: |
BROWNELL, MICHAEL PHILIP;
(LOS GATOS, CA) ; MAVEETY, JAMES G.; (SAN JOSE,
CA) |
Correspondence
Address: |
KENYON & KENYON
1500 K STREET, N.W., SUITE 700
WASHINGTON
DC
20005
US
|
Family ID: |
23716744 |
Appl. No.: |
09/432578 |
Filed: |
November 12, 1999 |
Current U.S.
Class: |
257/714 ;
257/E23.088 |
Current CPC
Class: |
H05K 1/0209 20130101;
H01L 2924/0002 20130101; F28F 2215/06 20130101; H01L 23/427
20130101; H01L 2924/00 20130101; F28D 15/046 20130101; F28D 15/0266
20130101; H01L 2924/0002 20130101 |
Class at
Publication: |
257/714 |
International
Class: |
H01L 023/34 |
Claims
What is claimed is:
1. An apparatus to dissipate heat, comprising: a top wall including
a plurality of hollow fins; a bottom wall; and a plurality of side
walls, said top wall including said plurality of hollow fins, said
bottom wall, and said plurality of side walls defining an inner
cavity, said inner cavity including a plurality of condenser
regions, each one of said plurality of condenser regions located
within one of said plurality of hollow fins, and said inner cavity
further including an evaporator region adjacent said bottom
wall.
2. The apparatus of claim 1, further comprising a two-phase fluid
disposed within said inner cavity.
3. The apparatus of claim 1, further comprising a wick disposed
within said inner cavity.
4. The apparatus of claim 1, further comprising a plenum cover
attached to a top surface of said top wall,.
5. The apparatus of claim 4, wherein said plenum cover includes an
aperture in a wall of said plenum cover, said plenum cover and said
top wall including said plurality of hollow fins define a plenum
chamber, and said plenum chamber includes a plenum working fluid
received through said aperture.
6. An integrated circuit package, comprising: a substrate; an
integrated circuit device mounted to said substrate; and a package
cover attached to said substrate enclosing the integrated circuit
device therebetween, said package cover including a top wall
including a plurality of hollow fins, a bottom wall, said
integrated circuit device thermally coupled to said bottom wall,
and a plurality of side walls, said top wall including said
plurality of hollow fins, said bottom wall, and said plurality of
side walls defining an inner cavity, said inner cavity including a
plurality of condenser regions, each one of said plurality of
condenser regions located within one of said plurality of hollow
fins, and said inner cavity further including an evaporator region
adjacent said bottom wall.
7. The integrated circuit package of claim 6, further comprising a
two-phase fluid disposed within said inner cavity.
8. The integrated circuit package of claim 6, further comprising a
wick disposed within said inner cavity.
9. The integrated circuit package of claim 6, further comprising a
plenum cover attached to said package cover.
10. The integrated circuit package of claim 9, wherein said plenum
cover includes an aperture in a wall of said plenum cover, said
plenum cover and package cover define a plenum chamber, and said
plenum chamber includes a plenum working fluid received through
said aperture.
11. A circuit board assembly, comprising: a circuit board; and a
semiconductor package coupled to said circuit board, said
semiconductor package including an integrated circuit device and a
package cover, said package cover including a top wall including a
plurality of hollow fins, a bottom wall, said integrated circuit
device thermally coupled to said bottom wall, and a plurality of
side walls, said top wall including said plurality of hollow fins,
said bottom wall, and said plurality of side walls defining an
inner cavity, said inner cavity including a plurality of condenser
regions, each one of said plurality of condenser regions located
within one of said plurality of hollow fins, and said inner cavity
further including an evaporator region adjacent said bottom
wall.
12. The circuit board assembly of claim 11, further comprising a
two-phase fluid disposed within said inner cavity.
13. The circuit board assembly of claim 11, further comprising a
wick disposed within said inner cavity.
14. The circuit board assembly of claim 11, further comprising a
plenum cover attached to said package cover.
15. The circuit board assembly of claim 14, wherein said plenum
cover includes an aperture in a wall of said plenum cover, said
plenum cover and said package cover define a plenum chamber, and
said plenum chamber includes a plenum working fluid received
through said aperture.
16. A method for dissipating heat from an integrated circuit
device, comprising: mounting the integrated circuit device to a
substrate; attaching a package cover to said substrate; thermally
coupling said package cover to said integrated circuit; receiving
heat from said integrated circuit device through a bottom wall of
said package cover; evaporating a two-phase fluid in an evaporator
region adjacent said bottom wall of said package cover; and
convecting heat from said evaporator region to a plurality of
condenser regions, each one of said plurality of condenser regions
located within one of a plurality of hollow fins of said package
cover.
17. The method of claim 16, further comprising attaching a plenum
cover to said package cover.
18. The method of claim 17, further comprising forcing a plenum
working fluid into said plenum chamber.
19. The method of claim 18, further comprising removing said plenum
working fluid from said plenum chamber.
20. The method of claim 19, wherein the integrated circuit device
is an integrated circuit device under test.
Description
FIELD OF THE INVENTION
[0001] Embodiments of the present invention relate to an integrated
circuit package.
BACKGROUND OF THE INVENTION
[0002] Advances in integrated circuit technology have resulted in
integrated circuit devices having increased circuit density,
increased clocking frequencies, and increased power consumption. As
a result, advanced integrated circuit devices such as
microprocessors generate substantial amounts of heat. To maintain
the performance and prevent degradation of integrated circuit
devices that generate a lot of heat, a package housing an
integrated circuit typically is coupled to a heat sink to transfer
and dissipate heat away from the integrated circuit device.
[0003] Known heat sink methods are generally passive. Such passive
methods rely on a heat sink to spread and dissipate the heat from
an integrated circuit device and air to convect the heat from the
heat sink. Known heat sinks are typically a cast heat sink and part
of a two-piece heat transfer system including a package cover and a
heat sink bolted to a cast cooling plate of the package cover. Cast
heat sinks and cover plates (e.g., cast from copper, aluminum,
etc.) can have high heat spreading resistances.
[0004] A known two-piece system for spreading heat generated by an
integrated circuit device includes a heat sink bolted to a package
cover including a heat pipe. The heat pipe of the cover can provide
enhanced heat spreading across the cover as compared to a cover
including a cast cover plate. Such a bolted, two-piece system,
however, includes a thermal interface between the cover and heat
sink. That thermal interface can create the largest thermal
resistance in the bolted, two-piece system. In view of the
foregoing, it can be appreciated that a substantial need exists for
a method and apparatus which can more effectively transfer and
dissipate heat from an integrated circuit device.
SUMMARY OF THE INVENTION
[0005] Embodiments of the present invention can include a
heatpipesink that dissipates heat and includes a top wall including
a plurality of hollow fins, a bottom wall, and a plurality of side
walls. The top wall including the plurality of hollow fins, the
bottom wall, and the plurality of side walls can define an inner
cavity. The inner cavity may include a plurality of condenser
regions, each one of the plurality of condenser regions can be
located within one of the plurality of hollow fins. The inner
cavity also can include an evaporator region adjacent said bottom
wall.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 shows a cross-sectional view of an apparatus in
accordance with an embodiment of the present invention.
[0007] FIG. 2 shows another embodiment of the present
invention.
[0008] FIG. 3 shows an isometric view of the plenum cover and
heatpipesink illustrated in FIG. 2.
[0009] FIG. 4 illustrates another embodiment of a heatpipesink in
accordance with an embodiment of the present invention.
[0010] FIG. 5 shows a cross-sectional view of the heatpipesink
illustrated in FIG. 4.
[0011] FIG. 6 shows a cross-sectional view of an apparatus in
accordance with another embodiment of the present invention.
[0012] FIG. 7 shows spreading and dissipation of heat in accordance
with an embodiment of the present invention.
DETAILED DESCRIPTION
[0013] Embodiments of apparatus and methods to dissipate heat from
an integrated circuit device are described. In the following
description, for purposes of explanation, numerous specific details
are set forth to provide a thorough understanding of the present
invention. It will be obvious, however, to one skilled in the art
that the present invention may be practiced without these specific
details. In other instances, well known structures and devices are
shown in block diagram form. Furthermore, it is readily apparent to
one skilled in the art that the specific sequences in which steps
are presented and performed are illustrative and it is contemplated
that the sequences can be varied and still remain within the spirit
and scope of the present invention.
[0014] FIG. 1 shows a cross-sectional view of an apparatus in
accordance with an embodiment of the present invention.
Heatpipesink 100, in one embodiment, includes a top wall 101
attached to first side wall 104 and second side wall 105. Top wall
101 can include a plurality of hollow fins 116. While heatpipesink
100 as illustrated in FIG. 1 includes four hollow fins 116, other
embodiments of a heatpipesink include two hollow fins, three hollow
fins, or more than four hollow fins, etc. In one embodiment, each
of the plurality of hollow fins 116 is a hollow fin that includes a
first vertical fin wall 191, a fin top wall 192, and a second
vertical fin wall 193. Heatpipesink 100 can include bottom wall 103
attached to first side wall 104 and second side wall 105. First
side wall 104 and second side wall 105 can extend from top wall 101
to beyond bottom wall 103, as is illustrated in FIG. 1. In another
embodiment, first side wall 104 and second side wall 105 extends
from top wall 101 to bottom wall 103.
[0015] In one embodiment, first side wall 104 and second side wall
105 are part of a quadrilateral (e.g., rectangular, trapezoidal,
etc.) side wall structure attached to top wall 101 and bottom wall
103 to define an inner cavity 107. In another embodiment, first
side wall 104 and second side wall 105 are part of a rounded (e.g.,
circular, elliptical) side wall structure attached to top wall 101
and bottom wall 103 to define an inner cavity 107. In a further
embodiment, first side wall 104 and second side wall 105 are part
of a polygonal (e.g., triangular, octagonal, etc.) side wall
structure attached to top wall 101 and bottom wall 103 to define an
inner cavity 107. A two-phase (e.g., vaporizable) fluid may reside
within inner cavity 107. Examples of a two-phase fluid that can
reside within embodiments of inner cavity 107 include purified
water, freon, etc. Top wall 101, first side wall 104, second side
wall 105, and bottom wall 103 can be composed of aluminum, copper,
other thermally conductive materials, etc.
[0016] Inner cavity 107 may include an evaporator region 108
located adjacent bottom wall 103. Inner cavity 107 can include a
plurality of condenser regions 106. In one embodiment, each one of
the plurality of condenser regions 106 is located within one of the
plurality of hollow fins 116. Heat transmitted through bottom wall
103 and into inner cavity 107 can evaporate the two-phase fluid in
the evaporator region 108. Vapor can be condensed to liquid in each
of the plurality of condenser regions 106. In one embodiment, the
vapor gives up heat as it condenses in a heat pipe fin, and that
heat is transmitted out of the inner cavity 107 through the walls
of the plurality of hollow fins 116, e.g., through first vertical
fin wall 191, fin top wall 192, and second vertical fin wall 193.
Inner cavity 107 may also include a wick 109. Condensed vapor
(i.e., liquid) can travel along the wick 109 toward the evaporator
region 108. In one embodiment, wick 109 includes grooved channels
on the interior surface of the walls defining the inner cavity 107.
In another embodiment, wick 109 includes a wire mesh.
[0017] In one embodiment of the present invention, inner cavity 107
does not include a wick, and each of the plurality of hollow fins
acts as a thermosyphon fin. A thermosyphon fin can be less
expensive to manufacture than a heat pipe fin. A thermosyphon fin
also can be less efficient than a heat pipe fin in terms of heat
transfer and dissipation. When a two-phase fluid condenses in a
condenser region of a thermosyphon fin, the condensate (i.e.,
liquid) may drip down the sides of the thermosyphon fin instead of
being advantageously transported by the capillary action of a wick
of a heat pipe fin.
[0018] Heatpipesink 100 can dissipate heat from a material in
contact with the bottom wall 103. In one embodiment, heatpipesink
100 can comprise a semiconductor package cover. First side wall 104
and second side wall 105 may extend beyond bottom wall 103 and can
be attached to a substrate 123 to enclose an integrated circuit
device 121 within a chamber defined by first side wall 104, bottom
wall 103, second side wall 105, and substrate 123. Integrated
circuit die 121 can be thermally coupled to bottom wall 103 by
thermal interface material 120. A plurality of solder bump joints
122 can mechanically and electrically couple integrated circuit die
121 to substrate 123. In one embodiment, integrated circuit device
121 generates heat when it is operated. Thermal interface material
120 transmits the heat to bottom wall 103 from integrated circuit
device 121. Bottom wall 103 transmits the heat to the two-phase
fluid in inner cavity 107. The heat is transmitted out of the
two-phase fluid and out of the heatpipesink 100 through the walls
of the plurality of hollow fins 116.
[0019] FIG. 2 shows another embodiment of the present invention.
Heatpipesink 200, in one embodiment, has a top wall 201 including a
plurality of hollow fins 216. Top wall 201 can include a top
surface 202. In one embodiment, top wall 201 is attached (e.g.,
welded, bonded, brazed, adhered, etc.) to a plurality of side walls
204, 205 at joints 210. Top wall 201, the plurality of side walls
204, 205, and a bottom wall 203 can define an inner cavity 207
having an evaporator region 208 located adjacent bottom wall 203.
Inner cavity 207 may also include a plurality of condenser regions
206, each of which is located within one of the plurality of hollow
fins 216. In one embodiment, inner cavity 207 includes a wire mesh
wick 209 and a two-phase fluid (not shown).
[0020] Heatpipesink 200 can comprise a package cover of an
integrated circuit package 250 and can be attached to a substrate
223 to enclose an integrated circuit device 221 between the
heatpipesink 200 and the substrate 223. The integrated circuit
device 221 may be thermally coupled to the bottom wall 203 by
thermal interface material 220 (e.g., an elastomer type material, a
grease and phase change material, etc.). A plurality of solder bump
connections 222 can mechanically and electrically couple integrated
circuit device 221 to substrate 223. The package 250 can include at
least one wiring layer (not shown) to electrically couple
integrated circuit device 221 to pins 224. Socket 230, in one
embodiment, includes a plurality of pin receptors 231. Package 250
and socket 230 can be mechanically and electrically attached via
pins 224 and pin receptors 231. Socket 230, in one embodiment, is
mechanically and electrically coupled to circuit board 240.
[0021] A plenum cover 260 can be attached to the top surface 202 of
top wall 201. In one embodiment, an o-ring seal is disposed between
the attachment points of top surface 202 and plenum cover 260.
Plenum cover 260 and top wall 201 can define a plenum chamber
through which a plenum working fluid can travel.
[0022] FIG. 3 shows an isometric view of the plenum cover 260 and
heatpipesink 200 illustrated in FIG. 2. Plenum cover 260 in one
embodiment includes a first aperture 262 in a first wall and a
second aperture 264 in a second wall of the plenum cover 260. A
first collar 263 can be attached to the plenum cover 260 at the
first aperture 262, and a second collar 265 can be attached at the
second aperture 264. In one embodiment, ducting (not shown) is
attached to each of first collar 263 and second collar 265 and a
plenum working fluid (e.g., a gas, a liquid, etc.) is forced
through the plenum cavity and across the plurality of hollow fins
216 of heatpipesink 200. In another embodiment, plumbing (not
shown) is attached to each of first collar 263 and second collar
265 and a plenum working fluid (e.g., a gas, a fluid, etc.) is
forced through the plenum cavity and across the plurality of heat
pipe fins of heatpipesink 200.
[0023] In another embodiment, the plenum cover includes a first
aperture in a first plenum wall, and a plenum working fluid is
injected into and removed from the plenum chamber via the first
aperture. For example, a first pipe coupled to the first aperture
can remove plenum working fluid from the plenum chamber. A second
pipe coupled to the first aperture and extending into the plenum
chamber can inject plenum working fluid into the plenum
chamber.
[0024] Embodiments of the present invention can provide the
capability for both passive and active cooling of an integrated
circuit device. An embodiment of the present invention can provide
passive cooling by thermally coupling a heatpipesink (e.g.
heatpipesink 100 of FIG. 1) to an integrated circuit device in an
operational setting (e.g., within a personal computer, workstation,
supercomputer, other electronic device, etc.) having an
uncontrolled ambient environment. Passive cooling systems can rely
on (i) a heat sink to spread and dissipate the heat from an
integrated circuit device, and (ii) ambient air to convect the heat
from the heat sink. A heatpipesink in accordance with an embodiment
of the present invention can provide more efficient heat spreading
and dissipation than a known cast heat sink. In one embodiment, the
heatpipesink moves heat from the base of the heatpipesink (e.g., a
bottom wall 103) to the heat pipe fins (e.g., the plurality of
hollow fins 116, each including wick 109) more efficiently than a
cast heat sink. A cast heat sink having a base and a plurality of
fins may have a high spreading resistance between the base and the
fins (e.g., through a cast material) as compared to the spreading
resistance through the inner cavity of a heatpipesink in accordance
with an embodiment of the present invention.
[0025] A heatpipesink in accordance with an embodiment of the
present invention may provide efficient heat transfer between a
heat source and the fluid (e.g., ambient air, a plenum working
fluid, etc.) surrounding the heatpipesink. When a cast heat sink is
attached to a package cover to create a two-piece cooling system, a
thermal interface is created between the cast heat sink and the
package cover. In an embodiment of the present invention, there is
no such thermal interface between the bottom wall of the package
cover (e.g., the bottom wall 103 of heatpipesink 100) and the heat
pipe fins (e.g., the plurality of hollow fins 116, each including
wick 109). Elimination of the thermal interface between a package
cover (e.g., a package cover including a heat pipe) and a cast heat
sink coupled to the package cover is advantageous because thermal
interface interactions can create the largest thermal resistance of
any two-piece system. Construction of a heatpipesink in accordance
with an embodiment of the present invention can eliminate the need
for expensive thermal interface materials between the pieces of a
two-piece system and flatness requirements (e.g., the flatness of
the bottom of the heat sink, the flatness of the top of the package
cover, [ensuring that the bondline thickness is maintained], etc.)
typically present in the construction of a two-piece system.
[0026] An embodiment of the present invention can provide active
cooling. Active cooling can result in better cooling of an object
producing heat (e.g., an engine, an integrated circuit device, a
processor, an amplifier, etc.) than passive cooling due to the use
of fluids to aid with heat transfer away from a heat sink. Active
cooling may also provide thermal control of an object producing
heat. In one embodiment, a device under test (DUT) is thermally
coupled to a heatpipesink (e.g., heatpipesink 200 illustrated in
FIG. 3), and a plenum cover (e.g., plenum cover 260 illustrated in
FIG. 3) is attached to the heatpipesink. Plumbing can be attached
to the plenum cover to circulate a plenum working fluid (e.g., a
liquid coolant) through the plenum chamber and around the heat pipe
fins. In one embodiment, the plenum working fluid is a liquid
having thermophysical properties that enhance heat transfer (e.g.,
H.sub.2O/propendal, fluorinert, ethylene glycol/H.sub.2O, etc.).
Heat from the DUT can first be spread and dissipated by the
heatpipesink, and the plenum working fluid can aid in convecting
the heat away from the heatpipesink. In such an embodiment, the DUT
temperature can be controlled advantageously to set temperature
points and/or ranges (e.g., a high temperature extreme, a low
temperature extreme, etc.). Higher DUT temperatures may lead to
performance degradation resulting in down binning of the device
(e.g., the DUT may be binned as a 500 megahertz device as opposed
to a 600 megahertz device, etc.). The superior thermal control that
can be provided by an embodiment of the present invention can
provide more precise binning of devices for a device manufacturer.
More precise binning can result in greater revenue for the device
manufacturer.
[0027] FIG. 7 shows spreading and dissipation of heat in accordance
with an embodiment of the present invention. Plenum cover 350 and
heatpipesink 300 are attached to define a plenum chamber 315. Heat
331 can be heat generated by an integrated circuit device (not
shown) thermally coupled to bottom wall 303 of heatpipesink 300.
Heat 331 can be transmitted across bottom wall 303 into an inner
cavity 307 having an evaporator region 308 located adjacent bottom
wall 303. In the evaporator region 308, heat 331 may vaporize a
two-phase fluid (not shown). The vapor including heat 332 may be
carried by convection currents through the inner cavity 307 into
the plurality of condenser regions 306, each one of which is
located within one of the plurality of heat pipe fins 316. In the
plurality of condenser regions 306, as the vapor condenses back to
a liquid and gives up heat, heat 333 can be transmitted out of the
plurality of heat pipe fins 316 into the plenum chamber 315 where a
plenum working fluid (not shown) can further transfer heat out of
the plenum chamber 315. Inner cavity 307 can include a wick 310
that aids in moving condensed liquid from the plurality of
condenser regions 306 to the evaporator region 300.
[0028] FIG. 4 illustrates another embodiment of a heatpipesink in
accordance with an embodiment of the present invention.
Heatpipesink 400 includes a plurality of heat pipe fins 410 and an
attachment flange 420. In one embodiment, and as illustrated in
FIG. 4, each of the plurality of heat pipe fins 410 can be a
rectangular pinfin. In another embodiment, each of the plurality of
heat pipe fins can be a square pinfin. In a further embodiment, the
plurality of heat pipe fins can include a plurality of types of
heat pipe fins. Examples of other types of pinfins include circular
pinfins, polygonal pinfins, oval pinfins, etc. A plenum cover (not
shown) can be attached to the heatpipesink 400 using the attachment
flange 420.
[0029] FIG. 5 shows a cross-sectional view of the heatpipesink 400
illustrated in FIG. 4. Heatpipesink 400 includes a bottom wall 403
and an inner cavity 415. Attachment flange 420 may be a generic
attachment flange to allow attachment of the heatpipesink 400 to an
automated pick and place fixture (not shown) that can be used to
test the performance an integrated circuit device 521 (e.g.,
stressing the device by changing environmental conditions and/or
running electrical patterns through the device, functionally
testing to determine the speed of the device and/or how well it
performs operations, a system level test, etc.). In such an
embodiment, the heatpipesink 400 can be thermally coupled to
integrated circuit device 521 via a thermal interface material
520.
[0030] FIG. 6 shows a cross-sectional view of an apparatus in
accordance with another embodiment of the present invention.
Heatpipesink 600, in one embodiment, includes a top wall 601
attached to side walls 604, 605. Top wall 601 can include a
plurality of heat pipe fins 616. Heatpipesink 600 can include
bottom wall 603 attached to side walls 604, 605. Bottom wall 603
can include a lowered platen 613. Top wall 601, bottom wall 603,
and side walls 604, 605 can define an inner cavity 607. A two-phase
fluid may reside within inner cavity 107.
[0031] Inner cavity 607 may include an evaporator region 608
located adjacent lowered platen 613. Inner cavity 607 can include a
plurality of condenser regions 606. Each one of the plurality of
condenser regions 106 can be located within one of the plurality of
heat pipe fins 616. Heat transmitted through lowered platen 613 and
into inner cavity 607 can evaporate the two-phase fluid in the
evaporator region 608. Vapor can be condensed to liquid in each of
the plurality of condenser regions 106. Inner cavity 607 may also
include a wick 609 attached to the interior surface of top wall
601, side walls 604, 605, and bottom wall 603. Condensed vapor
(i.e., liquid) can travel along the wick 609 toward the evaporator
region 608.
[0032] A support post 650 can be disposed within inner cavity 607
to structurally reinforce heat pipe fin 616. In one embodiment,
support post 650 is attached to an interior surface of a fin top
wall 692 of heat pipe fin 616 and to an interior surface of lowered
platen 613 of bottom wall 603. In another embodiment, support post
650 is attached in part to an interior surface of bottom wall 603.
A support post wick 659 can be attached to support post 650.
[0033] Heatpipesink 600 can dissipate heat from a material in
contact with the bottom wall 603. In one embodiment, heatpipesink
600 can comprise a semiconductor package cover. Side walls 604, 605
may extend beyond bottom wall 603 and can be attached to a
substrate 623 to enclose an integrated circuit device 621 within a
chamber defined by side walls 604, 605, bottom wall 103, and
substrate 623. Integrated circuit die 621 can be thermally coupled
to the lowered platen 613 of bottom wall 603 by thermal interface
material 620. A plurality of solder bump joints 622 can
mechanically and electrically couple integrated circuit die 621 to
substrate 623. In one embodiment, integrated circuit device 621
generates heat when it is operated. Thermal interface material 620
transmits the heat to lowered platen 613 of bottom wall 603 from
integrated circuit device 621. Bottom wall 603 transmits the heat
to the two-phase fluid in inner cavity 607. The heat is transmitted
out of the two-phase fluid and out of the heatpipesink 600 through
the walls of the plurality of heat pipe fins 616.
[0034] In one embodiment, the lowered platen 613 of bottom wall 603
provides for an advantageous thermal interface between heatpipesink
600 and integrated circuit device 621 that accommodates tall
components 625 (e.g., components that are taller than the total
height of an integrate circuit device and a thermal interface
material, etc.) disposed within the semiconductor package and
electrically coupled to the integrated circuit device 621. Examples
of components 625 include chip inductors, capacitors, etc.
[0035] As illustrated in FIG. 6, heatpipesink 600 can be part of a
semiconductor package that is operated in an upside down position.
In one such embodiment, heat pipe fins 616 can be pointed down such
that liquid present within the inner cavity 607 may pool within the
heat pipe fins 616 (e.g., toward the fin top wall 692) due to
gravitational forces acting upon the liquid. The support post wick
659 can improve wicking of the liquid from the heat pipe fins 616
toward the evaporator region 608 when the semiconductor package is
operated in an upside down position.
[0036] Embodiments of the present invention advantageously allow
heat to be spread and dissipated from an integrated circuit device.
In one embodiment, a heatpipesink can comprise a package cover and
include heat pipe fins that lacks the thermal interface typically
present between a package cover and a cast heat sink. Such an
embodiments can provide a more efficient heat transfer than a
package cover/cast heat sink combination. In another embodiment,
the heatpipesink advantageously spreads heat from the base of a
heat sink to the fins of the heat sink more efficiently than known
cast heat sinks.
[0037] In the foregoing detailed description, apparatus and methods
in accordance with embodiments of the present invention have been
described with reference to specific exemplary embodiments.
Accordingly, the present specification and figures are to be
regarded as illustrative rather than restrictive.
* * * * *