U.S. patent application number 12/180711 was filed with the patent office on 2008-12-04 for cooling an electronic device utilizing spring elements with fins.
This patent application is currently assigned to International Business Machines Corporation. Invention is credited to John P. Karidis, Mark D. Schultz, Bucknell C. Webb.
Application Number | 20080298016 12/180711 |
Document ID | / |
Family ID | 37523918 |
Filed Date | 2008-12-04 |
United States Patent
Application |
20080298016 |
Kind Code |
A1 |
Karidis; John P. ; et
al. |
December 4, 2008 |
COOLING AN ELECTRONIC DEVICE UTILIZING SPRING ELEMENTS WITH
FINS
Abstract
A method for cooling an electronic device includes forming a
spring structure by coupling a plurality of spring elements with a
fin portion oriented at an angle, wherein a first end of the fin
portion has a narrowed tip; coupling the spring structure with a
planar heat-conducting material to form a first heat-conducting
layer; positioning the first heat-conducting layer such that the
planar heat-conducting material is on top; and placing the first
heat-conducting layer over the electronic device such that the fin
portion is oriented at an angle toward the electronic device, and
such that the narrowed tip of the fin portion is in contact with
the top surface of the electronic device.
Inventors: |
Karidis; John P.; (Ossining,
NY) ; Schultz; Mark D.; (Ossining, NY) ; Webb;
Bucknell C.; (Ossining, NY) |
Correspondence
Address: |
MICHAEL BUCHENHORNER, P.A.
8540 SW 83 STREET, SUITE 100
MIAMI
FL
33143
US
|
Assignee: |
International Business Machines
Corporation
Armonk
NY
|
Family ID: |
37523918 |
Appl. No.: |
12/180711 |
Filed: |
July 28, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11151843 |
Jun 14, 2005 |
7408780 |
|
|
12180711 |
|
|
|
|
Current U.S.
Class: |
361/698 ;
257/E23.09 |
Current CPC
Class: |
H01L 2924/0002 20130101;
H01L 2924/0002 20130101; H01L 2924/00 20130101; H01L 23/433
20130101 |
Class at
Publication: |
361/698 |
International
Class: |
H05K 7/20 20060101
H05K007/20 |
Claims
1. A method for cooling an electronic device, the method
comprising: forming a spring structure by coupling a plurality of
spring elements comprising any one of a leaf spring and a helical
spring formed of a heat conducting metal with a fin portion
oriented at an angle and wherein a first end of the fin portion
comprises a narrowed tip; coupling the spring structure with a
planar heat-conducting material to form a first heat-conducting
layer; positioning the first heat-conducting layer such that the
planar heat-conducting material is on top; and placing the first
heat-conducting layer over the electronic device such that the fin
portion is oriented at an angle toward the electronic device, and
such that the narrowed tip of the fin portion is in contact with a
top surface of said electronic device; wherein, when said
electronic device is operating, a heat path from said electronic
device is provided by at least one of the plurality of spring
elements to provide cooling; and wherein the plurality of spring
elements provide mechanical compliance.
2. The method of claim 1 wherein placing the first heat-conducting
layer comprises attaching the fin portion to the electronic
device.
3. The method of claim 1 further comprising: introducing a second
heat-conducting layer between the spring structure and the
electronic device, wherein the fin portion of at least one of the
spring elements is coupled with the second heat-conducting
layer.
4. The method of claim 3, wherein introducing the second
heat-conducting layer comprises applying one or more of: thermally
conductive paste; thermally conductive adhesive; solder; indium;
and a heat conducting metal, over a top surface of the electronic
device.
5. The method of claim 1, wherein forming the spring structure
comprises coupling a plurality of copper spring elements with the
fin portion.
6. A method for cooling an electronic device, the method
comprising: forming a spring structure by coupling a plurality of
spring elements comprising any one of a leaf spring and a helical
spring formed of a heat conducting metal with a fin portion
oriented at an angle and wherein a first end of the fin portion
comprises a narrowed tip; coupling the spring structure with a
planar heat-conducting material to form a first heat-conducting
layer; positioning the first heat-conducting layer such that the
fin portion is underneath the plurality of spring elements; placing
the first heat-conducting layer over the electronic device such
that the narrowed tip of the fin portion is in contact with a top
surface of said electronic device; and applying coolant to fill
gaps within the first heat-conducting layer for cooling the
plurality of spring elements; wherein, when said electronic device
is operating, a heat path from said electronic device is provided
by at least one of the plurality of spring elements to provide
cooling; and wherein the plurality of spring elements provide
mechanical compliance.
7. The method of claim 6 wherein applying the coolant comprises
injecting the coolant into the first heat-conducting layer.
8. The method of claim 6 wherein applying the coolant comprises
pumping the coolant into the first heat-conducting layer.
9. The method of claim 6 wherein applying the coolant comprises
applying any one of a gaseous or a liquid heat-carrying
material.
10. The method of claim 9 wherein applying the coolant comprises
applying a liquid metal comprising one or more of: mercury;
gallium; and a gallium alloy.
11. The method of claim 6 wherein applying the coolant comprises
applying a non-metal liquid coolant comprising one or more of oil
and water.
12. The method of claim 6 further comprising sealing the first
heat-conducting layer to contain the coolant.
13. The method of claim 6 further comprising introducing a second
heat conducting layer disposed between the first heat-conducting
layer and the electronic device, wherein the fin portion of at
least one of the spring elements is coupled to the second
heat-conducting layer.
14. The method of claim 13, wherein introducing the second
heat-conducting layer comprises applying one or more of: a
thermally conductive paste; a thermally conductive adhesive;
solder; indium; and a heat conducting metal to the top surface of
the electronic device.
15. A method for cooling an electronic device, the method
comprising: forming a spring structure by densely packing an array
of rod elements formed of a semi-rigid, high thermal conductivity
material; coupling the spring structure with a planar conformable
high thermo conductivity membrane to form a first compressible
heat-conducting layer; positioning the first compressible
heat-conducting layer such that the array of rod elements is
underneath the conformable high thermo conductivity membrane;
introducing a second compressible heat-conducting layer; placing
the first compressible heat-conducting layer over the second
compressible heat-conducting layer to form a coolant structure,
such that the array of rod elements is disposed between the two
compressible heat-conducting layers, wherein each individual rod
element exhibits compression and elongation in the x, y and z
directions when the electronic device is in use; attaching a rigid
structure to a structure underneath the electronic device such that
the rigid structure surrounds a periphery of the electronic device;
and attaching the coolant structure to said rigid structure such
that the coolant structure is within the rigid structure and
coupled with the electronic device; and applying coolant to fill
gaps within the first heat-conducting layer for cooling the
plurality of spring elements; wherein, when said electronic device
is operating, a heat path from said electronic device is provided
by the array of rod elements to provide cooling, and wherein the
compressible heat-conducting layers provide heat compliance in
accordance with dimensional changes in the electronic device when
in use.
16. The method of claim 15 further comprising forming liquid inlets
and liquid outlets into the rigid structure.
17. The method of claim 16 wherein applying the coolant comprises
injecting the coolant through the liquid inlets such that the
coolant is carried into and through the gaps and out of the coolant
structure through the liquid outlets.
18. The method of claim 17 further comprising sealing the first
heat-conducting layer in order to contain the coolant.
19. The method of claim 15 wherein introducing the second
heat-conducting layer comprises applying one or more of: a
thermally conductive paste; a thermally conductive adhesive;
solder; indium; and a heat conducting metal to the top surface of
the electronic device.
20. The method of claim 15 wherein attaching the rigid structure
comprises attaching the rigid structure to a printed circuit board.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of, and claims priority
from, commonly-owned and co-pending U.S. patent application Ser.
No. 11/151,843, filed on Jun. 14, 2005 under Attorney Docket Number
YOR920040495US1.
STATEMENT REGARDING FEDERALLY SPONSORED-RESEARCH OR DEVELOPMENT
[0002] None.
INCORPORATION BY REFERENCE OF MATERIAL SUBMITTED ON A COMPACT
DISC
[0003] None.
FIELD OF THE INVENTION
[0004] The invention disclosed broadly relates to the field of
cooling devices for electronic components, and more particularly
relates to the field of heat sinks for microprocessors.
BACKGROUND OF THE INVENTION
[0005] During the normal operation of a computer, integrated
circuit devices generate significant amounts of heat. This heat
must be continuously removed, or the integrated circuit device may
overheat, resulting in damage to the device and possibly a
reduction in operating performance. Cooling devices, such as heat
sinks, have been used in conjunction with integrated circuit
devices in order to avoid such overheating. Generally, a passive
heat sink in combination with a system fan has provided a
relatively cost-effective cooling solution. Recently, however, the
power of integrated circuit devices such as microprocessors has
increased exponentially, resulting in a significant increase in the
amount of heat generated by these devices, thereby necessitating a
more efficient cooling solution.
[0006] It is becoming extremely difficult to extract the heat
generated by semiconductor devices (processors, in particular) that
continue to generate more and more heat in the same amount of
space. Heat is typically extracted by coupling a heat spreader and
thermal cap to the semiconductor and a heat sink. This coupling
typically involves a thermal paste which serves to not only
transfer heat but provide some degree of mechanical compliance to
compensate for dimensional changes driven by the high temperatures.
This paste is often a weak link in the thermal path. Attempts to
thin this layer have resulted in failure of the layer when it is
exposed to dimensional changes due to heat.
[0007] One approach to this problem includes the use of spring
loaded fingers with thermal paste in between them and a thermal
paste interface to the chip. This solution is limited in
performance by the thermal paste and in design by the requirement
for consistent spring loading. Liquid metal has been proposed on
its own as a thermal interface material, but could have significant
difficulty dealing with large z-axis thermally induced excursions,
requiring some compliance elsewhere in the package or (if the
largest spacing seen is still thermally acceptable) some sort of
edge reservoir design.
[0008] Therefore, a need exists to overcome the problems with the
prior art as discussed above, and particularly for a way to cool
small electronic devices using a thermally compliant material.
SUMMARY OF THE INVENTION
[0009] Briefly, according to an embodiment of the present
invention, a method for cooling an electronic device includes steps
or acts of: forming a spring structure by coupling a plurality of
spring elements with a fin portion oriented at an angle, wherein a
first end of the fin portion has a narrowed tip; coupling the
spring structure with a planar heat-conducting material to form a
first heat-conducting layer; positioning the first heat-conducting
layer such that the planar heat-conducting material is on top; and
placing the first heat-conducting layer over the electronic device
such that the fin portion is oriented at an angle toward the
electronic device, and such that the narrowed tip of the fin
portion is in contact with the top surface of the electronic
device.
[0010] According to another embodiment of the present invention, a
method for cooling an electronic device includes the steps or acts
as described above, along with an additional step of applying
coolant to fill the gaps within the first heat-conducting layer in
order to cool the spring elements.
[0011] In another embodiment of the present invention, a method for
cooling an electronic device includes steps or acts of: forming a
spring structure by densely packing an array of rod elements formed
of a semi-rigid, high thermal conductivity material; coupling the
spring structure with a planar conformable high thermo conductivity
membrane to form a first compressible heat-conducting layer;
introducing a second compressible heat-conducting layer; placing
the first compressible heat-conducting layer over the second
compressible heat-conducting layer to form a coolant structure.
Further, a rigid structure is attached to the printed circuit board
or other structure beneath the electronic device. This rigid
structure surrounds the periphery of the electronic device and
supports the cooling device. Coolant is injected into the cooling
device through fluid ingress spots in the rigid structure. The
terms "above" and "below" are only used herein to suggest relative
positions of the components and do not imply any orientation of the
components.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The subject matter which is regarded as the invention, is
particularly pointed out and distinctly claimed in the claims at
the conclusion of the specification. The foregoing and other
features and also the advantages of the invention will be apparent
from the following detailed description taken in conjunction with
the accompanying drawings.
[0013] FIG. 1 is a cross-sectional side view of a cooling structure
for an electronic device, the cooling structure including spring
elements and a plate, according to one embodiment of the present
invention.
[0014] FIG. 2 is another cross-sectional side view of the cooling
structure of FIG. 1.
[0015] FIG. 3 is a cross-sectional side view of a cooling structure
for an electronic device, the cooling structure including spring
elements, according to one embodiment of the present invention.
[0016] FIG. 4 is another cross-sectional side view of the cooling
structure of FIG. 3.
[0017] FIG. 5 is a cross-sectional side view of a cooling structure
for an electronic device, the cooling structure including spring
elements and a liquid, according to one embodiment of the present
invention.
[0018] FIG. 6 is another cross-sectional side view of the cooling
structure of FIG. 5.
[0019] FIG. 7 is a cross-sectional side view of a cooling structure
for an electronic device, the cooling structure including spring
elements with fins and a plate, according to one embodiment of the
present invention.
[0020] FIG. 8 is another cross-sectional side view of the cooling
structure of FIG. 7.
[0021] FIG. 9 is a cross-sectional side view of a cooling structure
for an electronic device, the cooling structure including spring
elements with a fin, a plate and a liquid, according to one
embodiment of the present invention.
[0022] FIG. 10 is another cross-sectional side view of the cooling
structure of FIG. 9.
[0023] FIG. 11 is a cross-sectional side view of a cooling
structure for an electronic device, the cooling structure including
spring elements with a fin, a plate, a seal and a liquid, according
to one embodiment of the present invention.
[0024] FIG. 12 is another cross-sectional side view of the cooling
structure of FIG. 11.
[0025] FIG. 13 is a cross-sectional side view of a cooling
structure for an electronic device, the cooling structure including
spring elements with a fin, a plate, liquid inlets/outlets and a
liquid, according to one embodiment of the present invention.
[0026] FIG. 14 is another cross-sectional side view of the cooling
structure of FIG. 13.
[0027] FIG. 15 is a perspective view of a series of spring elements
in a stacked arrangement.
[0028] FIG. 16 shows the spring elements of FIG. 15 in a tighter
stacked arrangement.
[0029] FIG. 17 shows the spring elements of FIG. 15 in an even
tighter stacked arrangement.
[0030] FIG. 18 is a cross-sectional side view of spring elements in
a stacked arrangement.
[0031] FIG. 19 shows the spring elements of FIG. 18 in a tighter
stacked arrangement.
[0032] FIG. 20 shows the spring elements of FIG. 18 in an even
tighter stacked arrangement.
[0033] FIG. 21 shows the spring elements of FIG. 18 in an even
tighter stacked arrangement.
[0034] FIG. 22 is a perspective view of a spring element.
[0035] FIG. 23 is a perspective view of a series of spring elements
of FIG. 22 in a stacked arrangement.
[0036] FIG. 24 shows the spring elements of FIG. 23 in a tighter
stacked arrangement.
[0037] FIG. 25 shows the spring elements of FIG. 23 in an even
tighter stacked arrangement.
[0038] FIG. 26 is a cross-sectional side view of spring elements in
a stacked arrangement.
[0039] FIG. 27 shows the spring elements of FIG. 26 in a tighter
stacked arrangement.
[0040] FIG. 28 shows the spring elements of FIG. 26 in an even
tighter stacked arrangement.
[0041] FIG. 29 shows the spring elements of FIG. 26 in an even
tighter stacked arrangement.
[0042] FIG. 30 is a cross-sectional side view of a cooling
structure for an electronic device, the cooling structure including
rod elements and a liquid coolant, according to one embodiment of
the present invention.
[0043] FIG. 31 is a high level block diagram showing an information
processing system useful for implementing one embodiment of the
present invention.
[0044] FIG. 32 is a cross-sectional side view of a cooling
structure for an electronic device, the cooling structure includes
a liquid with vaporizing capability, a compliant membrane and
spring elements with fins, according to one embodiment of the
present invention.
[0045] FIG. 33 is another cross-sectional side view of the cooling
structure of FIG. 32.
[0046] FIG. 34 is a cross-sectional side view of a cooling
structure for an electronic device, the cooling structure includes
a container for containing a liquid with vaporizing capability, a
compliant membrane and spring elements with fins, according to one
embodiment of the present invention.
[0047] FIG. 35 is another cross-sectional side view of the cooling
structure of FIG. 34.
[0048] FIG. 36 is a cross-sectional side view of a cooling
structure for an electronic device, the cooling structure includes
a container for containing a liquid with vaporizing capability and
spring elements with fins, according to one embodiment of the
present invention.
[0049] FIG. 37 is another cross-sectional side view of the cooling
structure of FIG. 36.
[0050] FIG. 38 is a cross-sectional side view of a cooling
structure for an electronic device, the cooling structure includes
a container for containing a liquid with vaporizing capability, a
compliant membrane and alternating spring elements with fins,
according to one embodiment of the present invention.
[0051] FIG. 39 is another cross-sectional side view of the cooling
structure of FIG. 38.
[0052] FIG. 40 is a cross-sectional side view of a cooling
structure for a reduced-size electronic device, the cooling
structure includes a container for containing a liquid with
vaporizing capability, a compliant membrane and spring elements
with fins, according to one embodiment of the present
invention.
[0053] FIG. 41 is another cross-sectional side view of the cooling
structure of FIG. 40.
DETAILED DESCRIPTION
[0054] In one embodiment present invention, an array of high
thermal conductivity spring elements (made of copper, for example)
with a high packing density is included, wherein the spring
elements are attached to or integrated with a thermally conductive
plate having either a flexible or somewhat rigid top (such as a
heat sink or cold cap side). In another embodiment of the present
invention, the array of spring elements can be either coupled or
placed in contact with (directly or via an interface material) a
subject electronic device, such as a semiconductor device.
[0055] In another embodiment of the present invention, the array of
spring elements can be coupled to or integrated with a conformable
high thermal conductivity bottom membrane. When coupled with a
membrane, the array of spring elements can have a relatively small
contact area that rapidly increases in cross section to the full
cross section of the spring element. This arrangement prevents the
end of the spring elements from adding unwanted rigidity to the
conformable membrane with minimal thermal resistance. Similarly,
the narrowing cross-section feature can also be implemented in the
case where the array of spring elements are either coupled or
placed in contact with a subject electronic device. However, if a
very thin thermal interface material is present between the array
of spring elements and the electronic device and there is high
spatial frequency content in the lack of flatness of the electronic
device surface, it may be desirable to narrow the spring element
ends.
[0056] In another embodiment of the present invention, if pure
perpendicular motion is desirable upon compression in the case
where the array of spring elements are coupled to or integrated
with a conformable high thermo conductivity bottom membrane, the
array of spring elements may have narrow sections at the ends where
they contact a heat sink. Packing density can be as high as
practical without interference within an expected compliance range.
In another embodiment of the present invention, the array of spring
elements can be a particular thickness through their entire
length.
[0057] In another embodiment of the present invention, if the space
occupied by the array of spring elements can be sealed without
compromising compliance, a thermally conductive liquid (such as
liquid metal) can be added to reduce the thermal path length. In
this embodiment, the present invention takes advantage of useful
thermal and physical characteristics of liquid metal. Liquid metal
is used as a thermal interface material between the array of spring
elements and a microprocessor or a plate coupled thereto.
[0058] Embodiments of the invention include advantages of providing
compliance in a location other than (or in addition to) the gap
area between the microprocessor and the heat conducting portion of
the invention neighboring the microprocessor. The present invention
is further advantageous as the forces on the microprocessor exerted
by physical changes brought on by heat in the x, y, and z
directions do not vary greatly. Further, the present invention
allows for z-compliance by utilizing the array of spring elements.
Thus, at least some the embodiments eliminate the necessity for
compliance in a film disposed between the microprocessor and a heat
spreader or heat sink. Additionally, at least some embodiments not
require the use of high-viscosity thermal paste, which is not
effective in very thin layers.
[0059] FIG. 1 is a cross-sectional side view of a cooling structure
for an electronic device, the cooling structure including spring
elements and a plate, according to one embodiment of the present
invention. FIG. 1 shows a heat-producing electronic device, a
microprocessor 102, located along the bottom of the assembly 100.
Disposed on the microprocessor 102 is a first layer 104, which can
be a solid layer for providing a heat path from the microprocessor
102 to the upper elements of the assembly 100. Examples of a solid
heat-conducting layer used for this purpose are a thermally
conductive adhesive and a solder such as indium. The first layer
104 is a planar surface that rests in contact with the
microprocessor 102. In another embodiment of the present invention,
the first layer 104 can be a conformable high thermal conductivity
membrane such as a copper sheet. In an embodiment where the first
layer 104 is a membrane, an additional layer of high thermal
conductivity material would be disposed between the microprocessor
102 and the membrane.
[0060] The cooling structure assembly 100 further includes an array
of spring elements 110 that contact or are coupled with the first
layer 104. The array of spring elements 110 comprise a plurality of
springs extending in the upper direction away from the source of
the heat, the microprocessor 102. Each of the array of spring
elements 110 draw heat away from the microprocessor 102 and allows
the heat to radiate out from the increased surface area of the
spring elements 110. Each of the array of spring elements 110 is
comprised of a heat conducting material such as copper. Further,
each of the array of spring elements 110 exhibits qualities of a
spring, which allows for compression and elongation in the
z-direction, i.e., the up and down direction, and in the x,
y-directions, i.e., the sideways directions. This provides
mechanical compliance in accordance with dimensional changes in the
microprocessor 102 during use. Note that while the spring elements
are shown all bent in the same direction, the springs may be bent
in alternate directions to remove any bias.
[0061] Each of the array of spring elements 110 comprises a spring
such as a leaf spring or a helix spring for offering resistance
when loaded. Each of the array of spring elements 110 provide
compliance between the top layer 106 and the microprocessor 102 and
works to keep the top layer 106 in close proximity to the
microprocessor 102. The composition and shape of each of the array
of spring elements 110 is described in greater detail below.
[0062] The cooling structure assembly 100 further includes a top
layer 106 comprising a planar surface, wherein the array of spring
elements 110 contact the top layer 106. The top layer 106 can be a
solid layer for providing a heat path from the microprocessor 102
to the upper elements of the assembly 100. The top layer 106 can be
a solid heat-conducting layer such as a thermally conductive
adhesive, solder, or solid metal structure.
[0063] FIG. 2 is another cross-sectional side view of the cooling
structure of FIG. 1. FIG. 2 shows the cooling structure assembly
100 comprising the top layer 106, the first layer 104 and the array
of spring elements 110 disposed between them. FIG. 2 also shows the
microprocessor 102 at the bottom of the cooling structure assembly
100.
[0064] FIG. 3 is a cross-sectional side view of a cooling structure
for an electronic device, the cooling structure including spring
elements, according to one embodiment of the present invention.
FIG. 3 shows the cooling structure assembly 300 comprising the top
layer 106, the microprocessor 102 at the bottom of the cooling
structure assembly 300 and the array of spring elements 110
disposed between them. The cooling structure assembly 300 of FIG. 3
is similar to the cooling structure assembly 100 of FIG. 1 except
for the presence of the first layer 104.
[0065] In this embodiment of the present invention, the array of
spring elements 110 are either coupled or placed in contact with
(directly or within an interface material) the microprocessor 102.
In another embodiment, the array of spring elements 110 can have a
relatively small profile at the end 302 of the spring elements that
contact the microprocessor 102. The profile would rapidly increase
in size to the full cross section of the spring element at the end
304 of the spring elements that contact the top layer 106. This
arrangement prevents the end 302 of the array of spring elements
101 from adding unwanted rigidity to the microprocessor 102 without
any substantial thermal resistance. In another embodiment, if a
very thin thermal interface material is present between the array
of spring elements 110 and the microprocessor 102 and there is high
spatial frequency content in the lack of flatness of the surface of
the microprocessor 102, it may be desirable to narrow the spring
element ends. In another embodiment of the present invention, the
array of spring elements 110 can be a particular thickness through
their entire length.
[0066] FIG. 4 is another cross-sectional side view of the cooling
structure of FIG. 3. FIG. 4 shows the cooling structure assembly
300 comprising the top layer 106, the microprocessor 102 at the
bottom of the cooling structure assembly 300 and the array of
spring elements 110 disposed between them.
[0067] FIG. 5 is a cross-sectional side view of a cooling structure
for an electronic device, the cooling structure including spring
elements and a liquid, according to one embodiment of the present
invention. FIG. 5 shows the cooling structure assembly 500
comprising a top layer 106, a microprocessor 102 at the bottom of
the cooling structure assembly 500 and an array of spring elements
110 disposed between them. Also included is a thermal interface
material 502 and a seal 504 for containing the thermal interface
material 502. The cooling structure assembly 500 of FIG. 5 is
similar to the cooling structure assembly 300 of FIG. 3 except for
the presence of the thermal interface material 502 and the seal
504. In this embodiment of the present invention, the array of
spring elements 110 are either coupled or placed in contact with
(directly or within an interface material) the microprocessor
102.
[0068] The thermal interface material 502 can be a liquid material
or a non-rigid solid material. In one embodiment, the thermal
interface material 502 is a non-metal liquid, such as oil or water,
or a liquid metal such as mercury, gallium or a gallium alloy such
as with tin or indium. A liquid 502 can be sealed with a seal 504
or container so as to restrict the escape of the liquid from the
desired area over the microprocessor 102. The liquid nature of the
liquid 502 allows the substance to fill the areas created by the
gap created between each of the spring elements 110. The liquid 502
provides a heat path from the microprocessor 102 to the upper
elements of the assembly 500 as the heat travels from the
microprocessor 102 to the top layer 106.
[0069] FIG. 6 is another cross-sectional side view of the cooling
structure of FIG. 5. FIG. 6 shows the cooling structure assembly
500 comprising a top layer 106, a microprocessor 102 at the bottom
of the cooling structure assembly 500 and an array of spring
elements 110 disposed between them. Also included is a thermal
interface material 502 and a seal 504 for containing the thermal
interface material 502.
[0070] FIG. 7 is a cross-sectional side view of a cooling structure
for an electronic device, the cooling structure including spring
elements with fins and a plate, according to one embodiment of the
present invention. FIG. 7 shows the cooling structure assembly 700
comprising the top layer 106, the first layer 104 and the array of
spring elements 710 disposed between them. FIG. 7 also shows the
microprocessor 102 at the bottom of the cooling structure assembly
700. In another embodiment of the present invention, the first
layer 104 can be a conformable high thermal conductivity membrane
such as a copper sheet. In an embodiment where the first layer 104
is a membrane, an additional layer of high thermal conductivity
material would be disposed between the microprocessor 102 and the
membrane. The cooling structure assembly 700 of FIG. 7 is similar
to the cooling structure assembly 100 of FIG. 1 except for the
presence of the elongated fin portion 702 of each of the array of
spring elements 110.
[0071] In another embodiment of the present invention, a coolant
would flow between and among the array of spring elements 710. The
coolant can be a liquid material or a gas material. In one
embodiment, the coolant is a non-metal liquid, such as oil or
water, or a liquid metal such as mercury, gallium or a gallium
alloy such as with tin or indium. The liquid nature of the liquid
allows the substance to fill the areas created by the gap created
between each of the spring elements 710. The liquid provides a heat
path from the microprocessor 102 to the upper elements of the
assembly 700 as the heat travels from the microprocessor 102 to the
top layer 106.
[0072] The portion 702 of each of the array of spring elements 710
comprises a plurality of fins extending in the upper direction away
from the source of the heat, the microprocessor 102. The inclusion
of the fins serves to effectively increase the surface area of the
surface of the first layer 104, which serves to dissipate heat into
a cooling gas or liquid. Each fin draws heat away from the
microprocessor 102 and allows the heat to be conducted out from the
increased surface area of the fins. The first layer 104 is a planar
surface that rests in contact with the microprocessor 102.
[0073] FIG. 8 is another cross-sectional side view of the cooling
structure of FIG. 7. FIG. 8 shows the cooling structure assembly
700 comprising the top layer 106, the first layer 104 and the array
of spring elements 710 disposed between them. FIG. 8 also shows the
microprocessor 102 at the bottom of the cooling structure assembly
700.
[0074] FIG. 9 is a cross-sectional side view of a cooling structure
for an electronic device, the cooling structure including spring
elements with a fin, a plate and a liquid, according to one
embodiment of the present invention. FIG. 9 shows the cooling
structure assembly 900 comprising the top layer 106, the first
layer 104 and the array of spring elements 710 disposed between
them. FIG. 9 also shows the microprocessor 102 at the bottom of the
cooling structure assembly 900, a cooling gas or liquid 902 (i.e.,
coolant), a seal 904 and a cooling gas or liquid inlet/outlet pair
906 and 908. The cooling structure assembly 900 of FIG. 9 is
similar to the cooling structure assembly 700 of FIG. 7 except for
the provisions for handling a coolant 902, such as seal 904 and
inlet/outlet pair 906 and 908. The cooling structure 900 can also
include a pair of flow-restricting end-plates (not shown in this
figure but described in greater detail below).
[0075] The coolant 902 can be a gas, a non-metal liquid material,
such as oil or water, or a metal liquid material such as mercury,
gallium or a gallium alloy such as with tin or indium. The coolant
902 is described in greater detail with reference to FIG. 7
above.
[0076] FIG. 9 also shows an inlet/outlet pair 906 and 908 for
allowing ingress and egress of the coolant 902. The inlet 906
allows for the intake of the coolant 902 as it is pumped or
otherwise pushed or propelled into the assembly 900. As the coolant
902 travels in the space filling the areas created by the gap
created between the microprocessor 102 and the top layer 106, the
coolant 902 absorbs the heat emanated from the first layer 104 and
the array of spring elements 710, including the fin structure 702.
The outlet 908 allows for the egress of the coolant 902 as it is
pumped or otherwise pulled or propelled out of the assembly 900 for
cooling and eventual recycling into the assembly 900.
[0077] FIG. 10 is another cross-sectional side view of the cooling
structure of FIG. 9. FIG. 10 shows the cooling structure assembly
900 comprising the top layer 106, the first layer 104 and the array
of spring elements 710 disposed between them. FIG. 10 also shows
the microprocessor 102 at the bottom of the cooling structure
assembly 900, a coolant 902 and a seal 904. The cooling structure
900 can also include a pair of flow-restricting end-plates 1002 and
1004 that fill the area on either end of the array of spring
elements 710 in FIG. 10. The purpose of the end-plates 1002 and
1004 is to restrict the flow of the coolant 902 into those spaces
so as to force the coolant 902 to flow in the area between the
multiple spring elements, which is where a higher degree of heat
dissipation occurs.
[0078] FIG. 11 is a cross-sectional side view of a cooling
structure for an electronic device, the cooling structure including
spring elements with a fin, a plate, a seal and a liquid, according
to one embodiment of the present invention. FIG. 11 shows the
cooling structure assembly 1100 comprising the top layer 106, the
first layer 104 and the array of spring elements 710 disposed
between them. FIG. 11 also shows the microprocessor 102 at the
bottom of the cooling structure assembly 1100, a coolant 902, a
seal 904, an internal seal 1106 and a liquid inlet/outlet pair 1102
and 1104. The cooling structure assembly 1100 of FIG. 11 is similar
to the cooling structure assembly 900 of FIG. 9 except for the
presence of the internal seal 1106 and the liquid inlet/outlet pair
1102 and 1104. The cooling structure 1100 can also include a pair
of flow-restricting end-plates (not shown in this figure but
described in greater detail below).
[0079] The internal seal 1106 provides a seal within the space
filling the areas created by the gap created between the
microprocessor 102 and the top layer 106. The internal seal 1106 is
located at a point in the cooling structure assembly 1100 where the
fin structures 702 of the array of spring elements 710 end. That
is, the height of the internal seal 1106 is the height at which the
fin structure 702 ends and the spring portion begins, for each of
the array of spring elements 710. This is the ideal location for
the internal seal 1106, as it forces the coolant 902 to travel
within the area of the fin structures 702 of the array of spring
elements 710, which is where a higher degree of heat dissipation
occurs in the cooling structure assembly 1100.
[0080] FIG. 11 also shows an inlet/outlet pair 1102 and 1104. The
inlet 1102 allows for the intake of the coolant 902 as it is pumped
or otherwise pushed or propelled into the assembly 1100. As the
coolant 902 travels in the space filling the areas created by the
gap created between the microprocessor 102 and the top layer 106
(namely, the area of the fin structures 702 of the array of spring
elements 710), the coolant 902 absorbs the heat emanated from the
first layer 104 and the fin structures 702 of the array of spring
elements 710. The outlet 1104 allows for the egress of the coolant
902 as it is pumped or otherwise pulled or propelled out of the
assembly 1100 for cooling and eventual recycling into the assembly
1100.
[0081] FIG. 12 is another cross-sectional side view of the cooling
structure of FIG. 11. FIG. 12 shows the cooling structure assembly
1100 comprising the top layer 106, the first layer 104 and the
array of spring elements 710 disposed between them. FIG. 12 also
shows the microprocessor 102 at the bottom of the cooling structure
assembly 1100, a thermal interface material 902, a seal 904 and an
internal seal 1106. The cooling structure 1100 can also include a
pair of flow-restricting end-plates 1202 and 1204 that fill the
area on either end of the array of spring elements 710 in FIG. 12.
The purpose of the end-plates 1202 and 1204 is to restrict the flow
of the coolant 902 into those spaces so as to force the coolant 902
to flow in the area between the multiple spring elements, which is
where a higher degree of heat dissipation occurs.
[0082] FIG. 13 is a cross-sectional side view of a cooling
structure for an electronic device, the cooling structure including
spring elements with a fin, a plate, inlets/outlets and a coolant,
according to one embodiment of the present invention. FIG. 13 shows
the cooling structure assembly 1300 comprising the top layer 106,
the first layer 104 and the array of spring elements 710 disposed
between them. FIG. 13 also shows the microprocessor 102 at the
bottom of the cooling structure assembly 1100, a coolant 902, a
seal 904 and a series of inlets/outlets. The cooling structure
assembly 1300 of FIG. 13 is similar to the cooling structure
assembly 1100 of FIG. 11 except for the presence of the series of
inlets/outlets and the lack of the internal seal 1106. The cooling
structure 1300 can also include a pair of flow-restricting
end-plates (not shown in this figure but described in greater
detail below).
[0083] FIG. 13 also shows a series of inlets/outlets. Orifices
1302, 1304, 1306, 1308, 1310 and 1312 are designated as inlets.
Orifices 1314, 1316, 1318, 1320 and 1322 are designated as outlets.
The inlets allow for the intake of the coolant 902 as it is pumped
or otherwise pushed or propelled into the assembly 1300. As the
coolant 902 travels in the space filling the areas created by the
gap created between the microprocessor 102 and the top layer 106
(namely, the area of the array of spring elements 710), the coolant
902 absorbs the heat emanated from the first layer 104 and the
array of spring elements 710. The outlets allow for the egress of
the coolant 902 as it is pumped or otherwise pulled or propelled
out of the assembly 1300 for cooling and eventual recycling into
the assembly 1300.
[0084] FIG. 14 is another cross-sectional side view of the cooling
structure of FIG. 13. FIG. 14 shows the cooling structure assembly
1300 comprising the top layer 106, the first layer 104 and the
array of spring elements 710 disposed between them. FIG. 14 also
shows the microprocessor 102 at the bottom of the cooling structure
assembly 1300, a coolant 902 and a seal 904. The cooling structure
1300 can also include a pair of flow-restricting end-plates 1402
and 1404 that fill the area on either end of the array of spring
elements 710 in FIG. 14.
[0085] FIG. 15 is a perspective view of a series of spring elements
in a stacked arrangement. A uniform first distance exists between
each spring element. Note each of the spring elements comprises a
single sheet of material, such as a thermally conductive sheet of
metal such as copper, that includes sections that are drilled out
or removed. The spring elements of FIG. 15 are examples of spring
elements that can be used in any of the cooling structure
assemblies 100, 300, 500, 700, 900, 1100 and 1300. The stacked
nature of the spring elements of FIG. 15 show how the spring
elements can be arranged for inclusion into any of the
aforementioned cooling structure assemblies. Note that FIGS. 15-17
show the series of spring elements as they are stacked during
assembly of a microprocessor assembly that includes the present
invention, in one embodiment.
[0086] FIG. 16 shows the spring elements of FIG. 15 in a tighter
stacked arrangement. A uniform second distance exists between each
spring element, wherein the second distance is shorter than the
first distance. FIG. 17 shows the spring elements of FIG. 15 in an
even tighter stacked arrangement. A uniform third distance exists
between each spring element, wherein the third distance is shorter
than the second distance.
[0087] FIG. 18 is a cross-sectional side view of spring elements in
a stacked arrangement. A uniform first distance exists between each
spring element. Compared to the spring elements of FIG. 15, note
that the spring elements of FIG. 18 each include an additional
element 1802 on the top end of the spring elements and an
additional element 1804 on the bottom end of the spring elements.
Note that FIGS. 18-20 show the series of spring elements as they
are stacked during assembly of a microprocessor assembly that
includes the present invention, in one embodiment.
[0088] FIG. 19 shows the spring elements of FIG. 18 in a tighter
stacked arrangement. A uniform second distance exists between each
spring element, wherein the second distance is shorter than the
first distance. FIG. 20 shows the spring elements of FIG. 18 in an
even tighter stacked arrangement. A uniform third distance exists
between each spring element, wherein the third distance is shorter
than the second distance. FIG. 21 shows the spring elements of FIG.
18 in an even tighter stacked arrangement. A uniform fourth
distance exists between each spring element, wherein the fourth
distance is shorter than the third distance. Note in FIG. 21 that
the additional element 1802 on the top end of the spring elements
and the additional element 1804 on the bottom end of the spring
elements has been removed. That is, the spring elements have been
trimmed. Note also that the purpose of the contact regions at the
top and bottom of the elements is to set the spacing between the
spring elements.
[0089] FIG. 22 is a perspective view of a spring element. Note that
the spring element comprises a single sheet of material, such as a
thermally conductive sheet of metal such as copper, that includes
sections that are drilled out or removed. The spring element of
FIG. 15 is an example of a spring element that can be used in any
of the cooling structure assemblies 100, 300, 500, 700, 900, 1100
and 1300. FIG. 23 is a perspective view of a series of spring
elements of FIG. 22 in a stacked arrangement. A uniform first
distance exists between each spring element. The stacked nature of
the spring elements of FIG. 23 show how the spring elements can be
arranged for inclusion into any of the aforementioned cooling
structure assemblies.
[0090] FIG. 24 shows the spring elements of FIG. 23 in a tighter
stacked arrangement. A uniform second distance exists between each
spring element, wherein the second distance is shorter than the
first distance. FIG. 25 shows the spring elements of FIG. 23 in an
even tighter stacked arrangement. A uniform third distance exists
between each spring element, wherein the third distance is shorter
than the second distance.
[0091] FIG. 26 is a cross-sectional side view of spring elements in
a stacked arrangement. A uniform first distance exists between each
spring element. Compared to the spring elements of FIG. 23, note
that the spring elements of FIG. 26 each include an additional
element 2602 on the top end of the spring elements and an
additional element 2604 on the bottom end of the spring elements.
FIG. 27 shows the spring elements of FIG. 26 in a tighter stacked
arrangement. A uniform second distance exists between each spring
element, wherein the second distance is shorter than the first
distance. FIG. 28 shows the spring elements of FIG. 26 in an even
tighter stacked arrangement. A uniform third distance exists
between each spring element, wherein the third distance is shorter
than the second distance. FIG. 29 shows the spring elements of FIG.
26 in an even tighter stacked arrangement. A uniform fourth
distance exists between each spring element, wherein the fourth
distance is shorter than the third distance. Note in FIG. 29 that
the additional element 2602 on the top end of the spring elements
and the additional element 2604 on the bottom end of the spring
elements has been removed.
[0092] FIG. 30 is a cross-sectional side view of a cooling
structure 3000 for an electronic device. The cooling structure 3000
includes rod elements 3020 and a liquid coolant 3024, according to
one embodiment of the present invention. FIG. 30 shows a
heat-producing electronic device 3002, such as a microprocessor,
located along the bottom of the assembly 3000. The microprocessor
3002 is disposed, such as through welding or soldering, onto a
circuit board 3030. An attachment 3022 surrounds the microprocessor
3002 and provides a base for placing a rigid structure 3028 such
that it is located above or over the microprocessor 3002. The
structure 3010 is also a rigid structure that may be integrated
with or separate from the rigid structure 3028. Disposed on the
microprocessor 3002 is a first layer 3004, which is a conformable
high thermo conductivity membrane for providing a heat path from
the microprocessor 3002 to the upper elements of the assembly 3000.
The first layer 3004 is a planar surface that rests in contact with
the microprocessor 3002. Disposed above the first layer 3004 is a
second layer 3006, which can also be a conformable high thermo
conductivity membrane for providing a heat path from the
microprocessor 3002 to the upper elements of the assembly 3000. The
second layer 3006 is a planar surface that rests in contact with a
compressible material layer 3008, such as rubber. The layer 3006 is
used as an adhesion/water-seal layer that is soft or pliable.
[0093] The term membrane refers to a thin substrate used to
separate different layers or materials. There is no inherent
application of tension assumed in conjunction with use of this
term. The membranes described above can be foils or flexible
sheets.
[0094] The cooling structure assembly 3000 further includes an
array of rigid rod elements 3020 that contact or are coupled with
the first layer 3004 and the second layer 3006. The array of rigid
rod elements 3020 are disposed between the first layer 3004 and the
second layer 3006. The array of rod elements 3020 comprises a
plurality of rods or small cylinders extending in a direction away
from the source of the heat, the microprocessor 3002. Each of the
array of rod elements 3020 draw heat away from the microprocessor
3002 and allows the heat to radiate out from the increased surface
area of the rod elements 3020. Each of the array of rod elements
3020 comprises a semi-rigid, high thermal conductivity material,
such as copper. Further, the array of rod elements 3020 are packed
densely. Equivalently, a set of fins can be used in place of the
rods.
[0095] Due to the conformable nature of the first layer 3004 and
the second layer 3006, each individual rod element has the freedom
to move upwards or downwards. Further, due to the compressible
nature of the compressible material layer 3008, each individual rod
element has the freedom to move upwards into the compressible
material layer 3008 or downwards away from compressible material
layer 3008, as the dimensions of the microprocessor 3002 change due
to heat buildup during use. Thus, the compressible material layer
3008 allows for compression and elongation in the z-direction,
i.e., the up and down direction, and in the x, y-directions, i.e.,
the sideways directions. This provides heat compliance in
accordance with dimensional changes in the microprocessor 102
during use.
[0096] FIG. 30 also shows that a thermal interface material 3024
can be located in the gap created between the structure 3010 and
the structure 3028 and in the area between first layer 3004 and the
second layer 3006. The thermal interface material 3024 can be a
non-metal liquid thermal interface material, such as oil or water,
or a metal liquid thermal interface material such as mercury,
gallium or a gallium alloy such as with tin or indium. The liquid
3024 can be sealed so as to restrict the escape of the liquid from
the desired area over the microprocessor 3002. The liquid nature of
the liquid 3024 allows the substance to fill the areas created by
the gap created between the structure 3010 and the structure 3028
and in the area between first layer 3004 and the second layer 3006.
The liquid 3024 provides a heat path from the microprocessor 3002
to the upper elements of the assembly 3000 as the heat travels from
the microprocessor 3002 upwards.
[0097] FIG. 30 also shows a liquid inlet/outlet pair 3016 and 3018.
The liquid inlet 3016 allows for the intake of the liquid thermal
interface material 3024 as it is pumped or otherwise pushed or
propelled into the assembly 3000. As the liquid thermal interface
material 3024 travels in the space filling the areas created by the
gap created between the structure 3010 and the structure 3028 and
in the area between first layer 3004 and the second layer 3006, the
liquid thermal interface material 3024 absorbs the heat emanated
from the first layer 3004 and the array of rod elements 3020. The
liquid outlet 3018 allows for the egress of the liquid thermal
interface material 3024 as it is pumped or otherwise pulled or
propelled out of the assembly 3000 for cooling and eventual
recycling into the assembly 3000.
[0098] FIG. 32 is a cross-sectional side view of a cooling
structure for an electronic device, the cooling structure includes
a liquid with vaporizing capability, a compliant membrane and
spring elements with fins, according to one embodiment of the
present invention.
[0099] FIG. 32 shows the cooling structure assembly 3200 comprising
a top layer 3206, a microprocessor 3202 at the bottom of the
cooling structure assembly 3200 and an array of spring elements
3210 disposed between them. In the space between the top layer 3206
and the microprocessor 3202 is the presence of a vaporizing liquid
3201. The cooling structure assembly 3200 of FIG. 32 is similar to
the cooling structure assembly 500 of FIG. 5 except for the
presence of the vaporizing liquid 3201 and the wicking capabilities
of the spring elements 3210. Wicking can be generated by the
surface tension in the narrow spaces between the elements and/or by
porous coatings in the surfaces of the elements. In this embodiment
of the present invention, the array of spring elements 3210 are
coupled or placed in contact with a compliant interface substrate
3203 disposed over the microprocessor 3202.
[0100] The liquid 3201 can be any liquid that can be used to cool
the microprocessor 3202, including any commercially available
microprocessor. Such a liquid 3201 can have qualities such that it
evaporates or vaporizes at temperatures that are normally reached
by the microprocessor 3202 during use. The vapor typically moves
upwards toward the top layer 3206 and away through the spaces
between the spring elements, areas which are further away from the
microprocessor 3202 and thus at a lower temperature. This leads to
condensation whereby the vapor returns to liquid form. Upon
returning to liquid form, the substance is pulled by wicking forces
and/or gravity back into the area above the microprocessor 3202
whereby the liquid 3201 resumes its heat absorbing function. The
spring portion of the array of spring elements 3210 may serve as a
pathway for returning the condensed liquid 3201 to the area above
the microprocessor 3202. The larger diameter passageways formed
near the base of the elements 3210 where they narrow and attach to
membrane 3203 provide low resistance flow channels to allow fluid
3201 to distribute easily across the stack of elements 3210. The
liquid 3201 can be sealed with a seal or container so as to
restrict the escape of the liquid from the desired area over the
microprocessor 3202. The liquid nature and surface tensions of the
liquid 3201 allows the substance to fill the areas created by the
gap created between each of the spring elements 3210. The lower
portions of the spring elements 3210 provide a heat path into the
liquid, causing vaporization as well as providing a conduction path
to the top surface 3206.
[0101] FIG. 33 is another cross-sectional side view of the cooling
structure of FIG. 32. The cooling structure assembly 3200 of FIG.
33 is similar to the cooling structure assembly 600 of FIG. 6
except for the presence of the vaporizing liquid 3201 and the
wicking capabilities of the spring elements 3210.
[0102] FIG. 34 is a cross-sectional side view of a cooling
structure for an electronic device, the cooling structure includes
a container for containing a liquid with vaporizing capability, a
compliant membrane and spring elements with fins, according to one
embodiment of the present invention.
[0103] FIG. 34 shows the cooling structure assembly 3400 comprising
a top layer 3406, a microprocessor 3402 at the bottom of the
cooling structure assembly 3400 and an array of spring elements
3410 disposed between them. The cooling structure assembly 3400 of
FIG. 34 is similar to the cooling structure assembly 500 of FIG. 5
except for the presence of a vaporizing liquid, the wicking
capabilities of the spring elements 3410 and the seal 3430. In this
embodiment of the present invention, the array of spring elements
3410 are either coupled or placed in contact with (directly or
within an interface material) the microprocessor 3402.
[0104] In the space between the top layer 3406 and the
microprocessor 3402 can be a vaporizing liquid, identical to the
liquid 3201 above. The liquid can be sealed with a seal 3430 or
container so as to restrict the escape of the liquid from the
desired area over the microprocessor 3402. The liquid nature of the
liquid allows the substance to fill the areas created by the gap
created between each of the spring elements 3410. The lower
portions of the spring elements 3410 provide a heat path into the
liquid, causing vaporization as well as providing a conduction path
to the top surface 3406.
[0105] In another embodiment of the present invention, the cooling
structure includes a condenser coupled to the seal 3430, whereby
the condenser allows the liquid in a vaporized form to enter into
the condenser, condense into a liquid form and then exit the
condenser and return to the space contained by seal 3430.
[0106] FIG. 35 is another cross-sectional side view of the cooling
structure of FIG. 34. The cooling structure assembly 3400 of FIG.
35 is similar to the cooling structure assembly 600 of FIG. 6
except for the presence of a vaporizing liquid, the wicking
capabilities of the spring elements 3410 and the seal 3430.
[0107] One embodiment of the invention comprises creating a locally
and globally compliant cooling structure with an integrated vapor
chamber made of a high thermal conductivity material, such as
copper, wherein the vapor chamber structure wicks the liquid, heats
and evaporates the liquid into vapor, and includes liquid return
paths when the vapor condenses. At least some embodiments allow the
use of very thin thermal interface materials of lower thermal
conductivity. At least some embodiments provide reasonable
compliance in the X-Y plane as well due to the thin bottom layer
3403. Virtually any thermal interface material (TIM) may be used. A
heat-generating electronic device package can be created with a
much larger surface area to which a heat sink or cold cap can be
coupled. This provides for very high heat removal capability.
[0108] At least some embodiments comprise creating an array of high
thermal conductivity (such as copper) elements comprising both a
spring portion (potentially doubling as a liquid return path) and a
wicking fin portion with a high packing density attached to or
integrated into either a flexible or relatively rigid top
plate.
[0109] The wicking fin portion can also provide liquid distribution
channels below the surface of the evaporating liquid, for lower
pressure drop and higher peak heat transfer capability. The
aforementioned elements are also attached to/integrated into a
conformable high thermal conductivity bottom (i.e., chip-side)
membrane. When attached to a membrane, the spring elements have a
small contact area that rapidly increase in cross section to the
full cross section of the spring elements. This prevents the ends
of the spring elements from adding unwanted rigidity to the
conformable membrane without adding substantial thermal resistance.
Packing density is as high as practical without interference within
the expected compliance range while maintaining vapor chamber
performance. Packing density and surface finish in the wicking
region can be optimized to improve capillary action and provide
enhanced heat-transfer/boiling surfaces.
[0110] In an embodiment of the present invention, the spring
elements can have a particular thickness through their entire
length, unlike what is shown in the FIGS. 32-35.
[0111] In another embodiment of the present invention, while the
spring and wicking portions can comprise differing sections of each
array element, as shown in FIG. 32, the functions of wicking and
spring force can be more integrated. Such an arrangement serves to
separately optimize the behavior of each section (spring and
wicking) of the array elements.
[0112] FIG. 34 shows one implementation for sealing the apparatus
and allowing for liquid return paths within the array assembly.
FIG. 34 shows the vapor chamber significantly larger than the chip.
This implementation provides for a larger contact area for the heat
sink or cold cap and allows more reservoir space that is not in
close proximity to the chip. Note that nothing prevents the use of
a separate condenser by routing the vapor away to the condenser and
returning the condensate to the wicking area.
[0113] FIG. 36 is a cross-sectional side view of a cooling
structure for an electronic device, the cooling structure includes
a container for containing a liquid with vaporizing capability and
spring elements with fins, according to one embodiment of the
present invention.
[0114] FIG. 36 shows the cooling structure assembly 3600 comprising
a top layer 3606, a microprocessor 3602 at the bottom of the
cooling structure assembly 3600 and an array of spring elements
3610 disposed between them. The cooling structure assembly 3600 of
FIG. 36 is similar to the cooling structure assembly 500 of FIG. 5
except for the presence of a vaporizing liquid, the wicking
capabilities of the spring elements 3610 and the seal 3630. In this
embodiment of the present invention, the array of spring elements
3610 are either coupled or placed in contact with (directly or
within an interface material) the microprocessor 3602.
[0115] In the space between the top layer 3606 and the
microprocessor 3602 can be a vaporizing liquid, identical to the
liquid 3601 above. The liquid can be sealed with a seal 3630 or
container so as to restrict the escape of the liquid from the
desired area over the microprocessor 3602 and to maintain the
liquid and vapor separate from the external atmosphere as it's
pressure may be substantially different from atmospheric pressure.
The nature of the liquid allows the substance to fill the areas
created by the gap created between each of the spring elements
3610. The liquid provides a heat path from the microprocessor 3602
to the upper elements of the assembly 3600 as the heat travels from
the microprocessor 3602 to the top layer 3606.
[0116] In another embodiment of the present invention, the cooling
structure includes a condenser coupled to the seal 3630, whereby
the condenser allows the liquid in a vaporized form to enter into
the condenser, condense into a liquid form and then exit the
condenser and return to the space contained by seal 3630.
Additional seal 3603 provides a seal for the liquid 3601 at the
juncture between the microprocessor 3602 and the seal 3630.
[0117] FIG. 37 is another cross-sectional side view of the cooling
structure of FIG. 34. The cooling structure assembly 3600 of FIG.
37 is similar to the cooling structure assembly 600 of FIG. 6
except for the presence of a vaporizing liquid, the wicking
capabilities of the spring elements 3610 and the seal 3630.
[0118] FIG. 38 is a cross-sectional side view of a cooling
structure for an electronic device, the cooling structure includes
a container for containing a liquid with vaporizing capability, a
compliant membrane and alternating spring elements with fins,
according to one embodiment of the present invention.
[0119] FIG. 38 shows the cooling structure assembly 3800 comprising
a top layer 3806, a microprocessor 3802 at the bottom of the
cooling structure assembly 3800 and an array of spring elements
3810 disposed between them. The cooling structure assembly 3800 of
FIG. 38 is similar to the cooling structure assembly 500 of FIG. 5
except for the presence of a vaporizing liquid, the wicking
capabilities of the spring elements 3810 and the seal 3830. In this
embodiment of the present invention, the array of spring elements
3810 are either coupled or placed in contact with (directly or
within an interface material) the microprocessor 3802.
[0120] In the space between the top layer 3806 and the
microprocessor 3802 can be a vaporizing liquid, identical to the
liquid 3801 above. The liquid can be sealed with a seal 3830 or
container so as to restrict the escape of the liquid from the
desired area over the microprocessor 3802. The liquid nature of the
liquid allows the substance to fill the areas created by the gap
created between each of the spring elements 3810. The liquid
provides a heat path from the microprocessor 3802 to the upper
elements of the assembly 3800 as the heat travels from the
microprocessor 3802 to the top layer 38606.
[0121] In another embodiment of the present invention, the spring
elements 3810 alternate in length and size, as shown by alternating
spring elements 3850 and 3851.
[0122] FIG. 39 is another cross-sectional side view of the cooling
structure of FIG. 38. The cooling structure assembly 3800 of FIG.
39 is similar to the cooling structure assembly 600 of FIG. 6
except for the presence of a vaporizing liquid, the wicking
capabilities of the spring elements 3810 and the seal 3830.
[0123] FIG. 40 is a cross-sectional side view of a cooling
structure for a reduced-size electronic device, the cooling
structure includes a container for containing a liquid with
vaporizing capability, a compliant membrane and spring elements
with fins, according to one embodiment of the present
invention.
[0124] FIG. 40 shows the cooling structure assembly 4000 comprising
a top layer 4006, a microprocessor 4002 at the bottom of the
cooling structure assembly 4000 and an array of spring elements
4010 disposed between them. The cooling structure assembly 4000 of
FIG. 40 is similar to the cooling structure assembly 500 of FIG. 5
except for the presence of a vaporizing liquid, the wicking
capabilities of the spring elements 4010 and the seal 4030. In this
embodiment of the present invention, the array of spring elements
4010 are either coupled or placed in contact with (directly or
within an interface material) the microprocessor 4002.
[0125] In the space between the top layer 4006 and the
microprocessor 4002 can be a vaporizing liquid, identical to the
liquid 3201. The liquid can be sealed with a seal 4030 or container
so as to restrict the escape of the liquid from the desired area
over the microprocessor 4002. The liquid nature and surface tension
of the liquid allows the substance to fill the areas created by the
gap created between each of the spring elements The lower portions
of the spring elements 4010 provide a heat path into the liquid,
causing vaporization as well as providing a conduction path to the
top surface 4006.
[0126] In another embodiment of the present invention, the cooling
structure includes a condenser coupled to the seal 4030, whereby
the condenser allows the liquid in a vaporized form to enter into
the condenser, condense into a liquid form and then exit the
condenser and return to the space contained by seal 4030.
[0127] FIG. 41 is another cross-sectional side view of the cooling
structure of FIG. 40. The cooling structure assembly 4000 of FIG.
41 is similar to the cooling structure assembly 600 of FIG. 6
except for the presence of a vaporizing liquid, the wicking
capabilities of the spring elements 4010 and the seal 4030.
[0128] The present invention can be utilized for cooling any of a
variety of electronic devices. In one embodiment of the present
invention, the present invention is used to cool a microprocessor
of an information processing system such as a computer. FIG. 31 is
a high level block diagram showing an information processing system
useful for implementing one embodiment of the present invention.
The computer system includes one or more processors, such as
processor 3104. The processor 3104 is connected to a communication
infrastructure 3102 (e.g., a communications bus, cross-over bar, or
network). Various software embodiments are described in terms of
this exemplary computer system. After reading this description, it
will become apparent to a person of ordinary skill in the relevant
art(s) how to implement the invention using other computer systems
and/or computer architectures.
[0129] The computer system can include a display interface 3108
that forwards graphics, text, and other data from the communication
infrastructure 3102 (or from a frame buffer not shown) for display
on the display unit 3110. The computer system also includes a main
memory 3106, preferably random access memory (RAM), and may also
include a secondary memory 3112. The secondary memory 3112 may
include, for example, a hard disk drive 3114 and/or a removable
storage drive 3116, representing a floppy disk drive, a magnetic
tape drive, an optical disk drive, etc. The removable storage drive
3116 reads from and/or writes to a removable storage unit 3118 in a
manner well known to those having ordinary skill in the art.
Removable storage unit 3118, represents a floppy disk, a compact
disc, magnetic tape, optical disk, etc. which is read by and
written to by removable storage drive 3116. As will be appreciated,
the removable storage unit 3118 includes a computer readable medium
having stored therein computer software and/or data.
[0130] In alternative embodiments, the secondary memory 3112 may
include other similar means for allowing computer programs or other
instructions to be loaded into the computer system. Such means may
include, for example, a removable storage unit 3122 and an
interface 3120. Examples of such may include a program cartridge
and cartridge interface (such as that found in video game devices),
a removable memory chip (such as an EPROM, or PROM) and associated
socket, and other removable storage units 3122 and interfaces 3120
which allow software and data to be transferred from the removable
storage unit 3122 to the computer system.
[0131] The computer system may also include a communications
interface 3124. Communications interface 3124 allows software and
data to be transferred between the computer system and external
devices. Examples of communications interface 3124 may include a
modem, a network interface (such as an Ethernet card), a
communications port, a PCMCIA slot and card, etc. Software and data
transferred via communications interface 3124 are in the form of
signals which may be, for example, electronic, electromagnetic,
optical, or other signals capable of being received by
communications interface 3124. These signals are provided to
communications interface 3124 via a communications path (i.e.,
channel) 3126. This channel 3126 carries signals and may be
implemented using wire or cable, fiber optics, a phone line, a
cellular phone link, an RF link, and/or other communications
channels.
[0132] In this document, the terms "computer program medium,"
"computer usable medium," and "computer readable medium" are used
to generally refer to media such as main memory 3106 and secondary
memory 3112, removable storage drive 3116, a hard disk installed in
hard disk drive 3114, and signals. These computer program products
are means for providing software to the computer system. The
computer readable medium allows the computer system to read data,
instructions, messages or message packets, and other computer
readable information from the computer readable medium. The
computer readable medium, for example, may include non-volatile
memory, such as a floppy disk, ROM, flash memory, disk drive
memory, a CD-ROM, and other permanent storage. It is useful, for
example, for transporting information, such as data and computer
instructions, between computer systems. Furthermore, the computer
readable medium may comprise computer readable information in a
transitory state medium such as a network link and/or a network
interface, including a wired network or a wireless network, that
allow a computer to read such computer readable information.
[0133] Computer programs (also called computer control logic) are
stored in main memory 3106 and/or secondary memory 3112. Computer
programs may also be received via communications interface 3124.
Such computer programs, when executed, enable the computer system
to perform the features of the present invention as discussed
herein. In particular, the computer programs, when executed, enable
the processor 3104 to perform the features of the computer system.
Accordingly, such computer programs represent controllers of the
computer system.
[0134] Although specific embodiments of the invention have been
disclosed, those having ordinary skill in the art will understand
that changes can be made to the specific embodiments without
departing from the spirit and scope of the invention. The scope of
the invention is not to be restricted, therefore, to the specific
embodiments. Furthermore, it is intended that the appended claims
cover any and all such applications, modifications, and embodiments
within the scope of the present invention.
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