U.S. patent application number 14/242879 was filed with the patent office on 2014-10-02 for silicon-based heat-dissipation device for heat-generating devices.
The applicant listed for this patent is Gerald Ho Kim, Jay Eunjae Kim. Invention is credited to Gerald Ho Kim, Jay Eunjae Kim.
Application Number | 20140290926 14/242879 |
Document ID | / |
Family ID | 51619675 |
Filed Date | 2014-10-02 |
United States Patent
Application |
20140290926 |
Kind Code |
A1 |
Kim; Gerald Ho ; et
al. |
October 2, 2014 |
Silicon-Based Heat-Dissipation Device For Heat-Generating
Devices
Abstract
Embodiments of a silicon-based heat-dissipation device and an
apparatus including a silicon-based heat-dissipation device are
described. In one aspect, an apparatus includes a silicon-based
heat-dissipation device which includes a base portion and a
protrusion portion. The base portion has a first primary side and a
second primary side opposite the first primary side. The protrusion
portion is on the first primary side of the base portion and
protruding therefrom. The protrusion portion includes multiple
fins. Each of at least two immediately adjacent fins of the fins of
the protrusion portion has a tapered profile in a cross-sectional
view with a first width near a distal end of the respective fin
being less than a second width at a base of the respective fin near
the base portion of the heat-dissipation device.
Inventors: |
Kim; Gerald Ho; (Carlsbad,
CA) ; Kim; Jay Eunjae; (Bellevue, WA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kim; Gerald Ho
Kim; Jay Eunjae |
Carlsbad
Bellevue |
CA
WA |
US
US |
|
|
Family ID: |
51619675 |
Appl. No.: |
14/242879 |
Filed: |
April 2, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61807655 |
Apr 2, 2013 |
|
|
|
Current U.S.
Class: |
165/185 |
Current CPC
Class: |
F28F 3/048 20130101;
H01L 23/3738 20130101; H01L 2924/00 20130101; H01L 23/3672
20130101; H01L 2924/0002 20130101; H01L 2924/0002 20130101; H01L
23/367 20130101 |
Class at
Publication: |
165/185 |
International
Class: |
F28F 3/02 20060101
F28F003/02 |
Claims
1. An apparatus, comprising: a silicon-based heat-dissipation
device comprising: a base portion having a first primary side and a
second primary side opposite the first primary side; and a
protrusion portion on the first primary side of the base portion
and protruding therefrom, wherein the second primary side of the
base portion is configured to have one or more heat-generating
devices embedded therein or physically coupled thereto such that at
least a portion of heat generated by the one or more
heat-generating devices is dissipated to the silicon-based
heat-dissipation device by conduction.
2. The apparatus of claim 1, wherein the base portion comprises a
slit that communicatively connects the first primary side and the
second primary side of the base portion.
3. The apparatus of claim 2, wherein, when each of more than one
heat-generating devices is embedded in or physically coupled to the
base portion, at least a first heat-generating device of the more
than one heat-generating devices is on a first side of the slit and
at least a second heat-generating device of the more than one
heat-generating devices is on a second side of the slit opposite
the first side of the slit such that the slit severs a direct-line
thermal coupling path via conduction through the base portion
between the first and the second heat-generating devices.
4. The apparatus of claim 2, wherein the slit comprises an L-shaped
slit.
5. The apparatus of claim 1, wherein the protrusion portion of the
silicon-based heat-dissipation device comprises a plurality of
fins.
6. The apparatus of claim 5, wherein the plurality of fins
comprises a plurality of straight fins.
7. The apparatus of claim 6, wherein a ratio of a height of the
fins, measured from the first primary side of the base portion in a
direction perpendicular to the first primary side, to a thickness
of each of the fins, measured across a respective one of the fins
in a direction parallel to the first primary side of the base
portion, is greater than 5:1.
8. The apparatus of claim 6, wherein a ratio of a height of the
fins, measured from the first primary side of the base portion in a
direction perpendicular to the first primary side, to a thickness
of the base portion, measured across the base portion in a
direction parallel to the first primary side of the base portion,
is greater than 5:1.
9. The apparatus of claim 6, wherein a spacing between every two
fins of the fins, measured between respective two fins of the fins
in a direction parallel to the first primary side of the base
portion, is greater than or equal to a thickness of each of the
fins, measured across a respective one of the fins in the direction
parallel to the first primary side of the base portion.
10. The apparatus of claim 5, wherein the plurality of fins
comprises a plurality of pin fins.
11. The apparatus of claim 5, wherein the plurality of fins
comprises a plurality of flared fins.
12. The apparatus of claim 1, further comprising: one or more
integrated circuits embedded in the second primary side of the base
portion or one or more electrically-driven devices physically
coupled to the second primary side of the base portion.
13. The apparatus of claim 2, further comprising: one or more
integrated circuits embedded in the second primary side of the base
portion or one or more electrically-driven devices physically
coupled to the second primary side of the base portion, wherein at
least a first one of the one or more integrated circuits or the one
or more electrically-driven devices is on a first side of the slit,
wherein at least a second one of the one or more integrated
circuits or the one or more electrically-driven devices is on a
second side of the slit opposite the first side of the slit, and
wherein the slit severs a direct-line thermal coupling path via
conduction through the base portion between the first one of the
one or more integrated circuits or the one or more
electrically-driven devices and the second one of the one or more
integrated circuits or the one or more electrically-driven
devices.
14. The apparatus of claim 1, wherein the silicon-based
heat-dissipation device is made of single-crystal silicon.
15. An apparatus, comprising: a silicon-based heat-dissipation
device comprising: a base portion having a first primary side and a
second primary side opposite the first primary side; and a
protrusion portion on the first primary side of the base portion
and protruding therefrom, the protrusion portion comprising a
plurality of fins, wherein each of at least two immediately
adjacent fins of the fins of the protrusion portion has a tapered
profile in a cross-sectional view with a first width near a distal
end of the respective fin being less than a second width at a base
of the respective fin near the base portion of the heat-dissipation
device.
16. The apparatus of claim 15, wherein the second primary side of
the base portion is configured to have one or more heat-generating
devices embedded therein or physically coupled thereto such that at
least a portion of heat generated by the one or more
heat-generating devices is dissipated to the silicon-based
heat-dissipation device by conduction.
17. The apparatus of claim 15, wherein a trench between the at
least two immediately adjacent fins has a relatively flat surface
with respect to a horizontal plane defined by the first primary
side of the base portion.
18. The apparatus of claim 15, wherein a trench between the at
least two immediately adjacent fins has a V-shaped notch with
respect to a horizontal plane defined by the first primary side of
the base portion.
19. The apparatus of claim 15, further comprising: one or more
integrated circuits embedded in the second primary side of the base
portion or one or more electrically-driven devices physically
coupled to the second primary side of the base portion, wherein the
base portion comprises a slit that communicatively connects the
first primary side and the second primary side of the base portion,
wherein at least a first one of the one or more integrated circuits
or the one or more electrically-driven devices is on a first side
of the slit, wherein at least a second one of the one or more
integrated circuits or the one or more electrically-driven devices
is on a second side of the slit opposite the first side of the
slit, and wherein the slit severs a direct-line thermal coupling
path via conduction through the base portion between the first one
of the one or more integrated circuits or the one or more
electrically-driven devices and the second one of the one or more
integrated circuits or the one or more electrically-driven
devices.
20. The apparatus of claim 15, wherein the silicon-based
heat-dissipation device is made of single-crystal silicon.
Description
CROSS REFERENCE TO RELATED PATENT APPLICATION
[0001] The present disclosure claims the priority benefit and is a
non-provisional of U.S. Patent Application No. 61/807,655, filed
Apr. 2, 2013 and entitled "Silicon-Based Heat Dissipation Device
For Heat-Generating Devices," which is herein incorporated by
reference.
TECHNICAL FIELD
[0002] The present disclosure generally relates to the field of
transfer of thermal energy and, more particularly, removal of
thermal energy from electrically-driven devices.
BACKGROUND
[0003] There are many applications, ranging from consumer
electronics to telecommunications and the like, in which
electrically-driven devices (e.g., semiconductor-based integrated
circuits) capable of performing various tasks are packed in close
proximity in a small form factor to serve various needs. Such
electrically-driven devices may include, for example, driver
circuits, microprocessors, graphics processors, memory chips,
global positioning system (GPS) chips, communications chips, laser
diodes including edge-emitting lasers and vertical-cavity
surface-emitting lasers (VCSELs), light-emitting diodes (LEDs),
photodiodes, sensors, etc. Many of such electrically-driven devices
inevitably generate thermal energy, or heat, in operation and thus
are heat sources during operation as well as for a period of time
after power off. As the number and complexity of the
functionalities performed by such electrically-driven devices
continue to increase and as the distance between
electrically-driven devices in the small form factor continues to
decrease, heat generated by such electrically-driven devices, as
heat sources, present technical challenges that need to be
addressed.
[0004] For one thing, performance, useful lifespan, or both, of an
electrically-driven device may be significantly impacted if the
heat generated by the device is not adequately dissipated or
otherwise removed from the device. Moreover, in many present-day
applications, given the close proximity between two or more
electrically-driven devices on the same substrate, e.g., printed
circuit board (PCB), a phenomenon of thermal coupling between the
two or more devices in close proximity may occur and result in the
heat generated by one of the devices being transferred to one or
more adjacent devices. When thermal coupling occurs, at least a
portion of the heat generated by a first electrically-driven
devices is transferred to a second electrically-driven device in
close proximity due to temperature gradient, such that the
temperature of the second electrically-driven device rises to a
point higher than it would be when no heat is transferred from the
first electrically-driven device to the second electrically-driven
device. More specifically, when thermal coupling occurs and when no
adequate heat transfer mechanism exists, heat generated by
electrically-driven devices in close proximity may detrimentally
deteriorate the performance and useful lifespan of some or all of
the affected devices. As electrically-driven devices generate heat,
they are referred to as heat-generating devices hereinafter.
[0005] Metal heat sinks or radiators, based on copper or aluminum
for example, have been a dominant heat sink choice for electronics
or photonics applications. As the form factor of electronic
components (e.g., integrated circuits or IC) gets smaller it is
impractical to build a small metal heat sink with a large surface
area heat sink. Other problems associated with metal heat sinks
include, for example, difficulty in precision alignment in mounting
laser diode bars, VCSELs, LEDs or chips in laser diode/VCSEL/LED
cooling applications, issues with overall compactness of the
package, corrosion of the metallic material in water-cooled
applications, difficulty in manufacturing, high-precision
fabrication, electrical isolation, etc. Yet, increasing demand for
higher power density in small form factor motivates the production
of a compact cooling package with fewer or none of the
aforementioned issues. Moreover, conventional packages typically
use wire bonding to provide electrical power to the
electrically-driven device(s) being cooled, but wire bonding may
add cost and complexity in manufacturing and may be prone to
defects in addition to occupying space unnecessarily.
SUMMARY
[0006] Various embodiments disclosed herein pertain to a technique,
design, scheme, device and mechanism for isolation of thermal
ground for multiple heat-generating devices on a substrate.
[0007] According to one aspect, an apparatus may include a
silicon-based heat-dissipation device. The silicon-based
heat-dissipation device may include a base portion and a protrusion
portion. The base portion may have a first primary side and a
second primary side opposite the first primary side. The protrusion
portion may be on the first primary side of the base portion and
may protrude therefrom. The second primary side of the base portion
may be configured to have one or more heat-generating devices
embedded therein or physically coupled thereto such that at least a
portion of heat generated by the one or more heat-generating
devices is dissipated to the silicon-based heat-dissipation device
by conduction.
[0008] In at least one embodiment, the base portion may include a
slit that communicatively connects the first primary side and the
second primary side of the base portion.
[0009] In at least one embodiment, when each of more than one
heat-generating devices is embedded in or physically coupled to the
base portion, at least a first heat-generating device of the more
than one heat-generating devices may be on a first side of the slit
and at least a second heat-generating device of the more than one
heat-generating devices may be on a second side of the slit
opposite the first side of the slit such that the slit severs a
direct-line thermal coupling path via conduction through the base
portion between the first and the second heat-generating
devices.
[0010] In at least one embodiment, the slit may include an L-shaped
slit.
[0011] In at least one embodiment, the protrusion portion of the
silicon-based heat-dissipation device may include a plurality of
fins.
[0012] In at least one embodiment, the plurality of fins may
include a plurality of straight fins.
[0013] In at least one embodiment, a ratio of a height of the fins,
measured from the first primary side of the base portion in a
direction perpendicular to the first primary side, to a thickness
of each of the fins, measured across a respective one of the fins
in a direction parallel to the first primary side of the base
portion, may be greater than 5:1.
[0014] In at least one embodiment, a ratio of a height of the fins,
measured from the first primary side of the base portion in a
direction perpendicular to the first primary side, to a thickness
of the base portion, measured across the base portion in a
direction parallel to the first primary side of the base portion,
may be greater than 5:1.
[0015] In at least one embodiment, a spacing between every two fins
of the fins, measured between respective two fins of the fins in a
direction parallel to the first primary side of the base portion,
may be greater than or equal to a thickness of each of the fins,
measured across a respective one of the fins in the direction
parallel to the first primary side of the base portion.
[0016] In at least one embodiment, the plurality of fins may
include a plurality of pin fins.
[0017] In at least one embodiment, the plurality of fins may
include a plurality of flared fins.
[0018] In at least one embodiment, the apparatus may further
include one or more integrated circuits embedded in the second
primary side of the base portion or one or more electrically-driven
devices physically coupled to the second primary side of the base
portion.
[0019] In at least one embodiment, the apparatus may further
include one or more integrated circuits embedded in the second
primary side of the base portion or one or more electrically-driven
devices physically coupled to the second primary side of the base
portion. At least a first one of the one or more integrated
circuits or the one or more electrically-driven devices may be on a
first side of the slit. At least a second one of the one or more
integrated circuits or the one or more electrically-driven devices
may be on a second side of the slit opposite the first side of the
slit. The slit may sever a direct-line thermal coupling path via
conduction through the base portion between the first one of the
one or more integrated circuits or the one or more
electrically-driven devices and the second one of the one or more
integrated circuits or the one or more electrically-driven
devices.
[0020] In at least one embodiment, the silicon-based
heat-dissipation device may be made of single-crystal silicon.
[0021] According to another aspect, an apparatus may include a
silicon-based heat-dissipation device. The silicon-based
heat-dissipation device may include a base portion and a protrusion
portion. The base portion may have a first primary side and a
second primary side opposite the first primary side. The protrusion
portion may be on the first primary side of the base portion and
protruding therefrom. The protrusion portion may include a
plurality of fins. Each of at least two immediately adjacent fins
of the fins of the protrusion portion may have a tapered profile in
a cross-sectional view with a first width near a distal end of the
respective fin being less than a second width at a base of the
respective fin near the base portion of the heat-dissipation
device.
[0022] In at least one embodiment, the second primary side of the
base portion may be configured to have one or more heat-generating
devices embedded therein or physically coupled thereto such that at
least a portion of heat generated by the one or more
heat-generating devices is dissipated to the silicon-based
heat-dissipation device by conduction.
[0023] In at least one embodiment, a trench between the at least
two immediately adjacent fins may have a relatively flat surface
with respect to a horizontal plane defined by the first primary
side of the base portion.
[0024] In at least one embodiment, a trench between the at least
two immediately adjacent fins may have a V-shaped notch with
respect to a horizontal plane defined by the first primary side of
the base portion.
[0025] In at least one embodiment, the apparatus may further
include one or more integrated circuits embedded in the second
primary side of the base portion or one or more electrically-driven
devices physically coupled to the second primary side of the base
portion. The base portion may include a slit that communicatively
connects the first primary side and the second primary side of the
base portion. At least a first one of the one or more integrated
circuits or the one or more electrically-driven devices may be on a
first side of the slit. At least a second one of the one or more
integrated circuits or the one or more electrically-driven devices
may be on a second side of the slit opposite the first side of the
slit. The slit may sever a direct-line thermal coupling path via
conduction through the base portion between the first one of the
one or more integrated circuits or the one or more
electrically-driven devices and the second one of the one or more
integrated circuits or the one or more electrically-driven
devices.
[0026] In at least one embodiment, the silicon-based
heat-dissipation device may be made of single-crystal silicon.
[0027] The proposed techniques are further described below in the
detailed description. This summary is not intended to identify
essential features of the claimed subject matter, nor is it
intended for use in determining the scope of the claimed subject
matter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] The accompanying drawings are included to provide a further
understanding of the disclosure, and are incorporated in and
constitute a part of the present disclosure. The drawings
illustrate embodiments of the disclosure and, together with the
description, serve to explain the principles of the disclosure. It
is appreciable that the drawings are not necessarily in scale as
some components may be shown to be out of proportion than the size
in actual implementation in order to clearly illustrate the concept
of the present disclosure.
[0029] FIG. 1 is a partial cross-sectional view of a
heat-dissipation device in accordance with an embodiment of the
present disclosure.
[0030] FIG. 2 is a partial cross-sectional view of a
heat-dissipation device in accordance with an embodiment of the
present disclosure.
[0031] FIG. 3 is a partial cross-sectional view of a
heat-dissipation device in accordance with an embodiment of the
present disclosure.
[0032] FIG. 4 is a perspective view of a heat-dissipation device in
accordance with an embodiment of the present disclosure.
[0033] FIG. 5 is a partial cross-sectional view of the
heat-dissipation device of FIG. 4.
[0034] FIG. 6 is a perspective top view of a device in accordance
with an embodiment of the present disclosure.
[0035] FIG. 7 is a perspective bottom view of the device of FIG.
6.
[0036] FIG. 8 is a side view of the device of FIG. 6.
[0037] FIG. 9 is a perspective top view of a device in accordance
with another embodiment of the present disclosure.
[0038] FIG. 10 is a perspective bottom view of the device of FIG.
9.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Overview
[0039] A compact heat sink or radiator built with silicon-based
material provide a compact and highly efficient heat sink for all
electronics applications such as driver circuits, microprocessors,
graphics processors, memory chips, GPS chips, communications chips,
laser diodes including edge-emitting lasers and VCSELs, LEDs,
photodiodes, sensors, etc. One advantage of a silicon-based heat
sink or radiator is that it can have a surface area more than ten
times that of a typical metal-based heat sink or radiator which may
be fabricated by extrusion, stamping or machining process. Besides,
the surface quality of the silicon fins of a silicon-based heat
sink or radiator can reach an optically polished quality surpassing
the surface quality of conventional metal-based heat sinks and
radiators. A silicon-based heat sink or radiator does not corrode
or become tarnished in atmosphere due to elements of the
environment. In contrast, metal-based heat sinks and radiators tend
to foul and/or corrode over time. The aforementioned advantages
enhance the reliability and thermal dissipation efficiency of
silicon-based heat sinks and radiators.
Illustrative Implementations
[0040] Each of FIGS. 1-3 respectively illustrates a partial
cross-sectional view of a silicon-based heat-dissipation device in
accordance with an embodiment of the present disclosure. FIG. 4
illustrates a silicon-based heat-dissipation device 101 in
accordance with an embodiment of the present disclosure. FIG. 5
illustrates dimensions associated with the silicon-based
heat-dissipation device of FIG. 4. The following description refers
to FIGS. 1-5.
[0041] Each of FIGS. 1-3 illustrates a respective embodiment of a
cross-sectional view of a fin structure of multiple straight fins
of a silicon-based heat-dissipation device 101. Due to efficient
thermal performance and compact structure of the silicon-based
heat-dissipation device 101, a surface area at least ten times that
of a typical metal-based heat sink or radiator to interact with air
or air-sol cooling can be achieved.
[0042] As shown in FIG. 1, in one embodiment, a fin structure 51 of
multiple straight fins of silicon-based heat dissipation device 101
includes a protrusion portion 51a and a base portion 51b. The
protrusion portion 51a has a number of fins protruding from a
horizontal plane 51c defined by the base portion 51b. Fins of fin
structure 51 have substantially straight and parallel sidewalls.
That is, in fin structure 51, a surface of a sidewall of a given
one of the fins is substantially parallel to a surface of an
opposing sidewall of an immediately adjacent fin. Further, a
surface of a sidewall of a given one of the fins is substantially
perpendicular to the horizontal plane 51c. Moreover, as shown in
FIG. 1, trenches, i.e., where the protrusion portion 51a come in
contact with the base portion 51b, of fin structure 51 are
relatively flat or horizontal with respect to the horizontal plane
51c.
[0043] As shown in FIG. 2, in one embodiment, a fin structure 52 of
multiple straight fins of silicon-based heat dissipation device 101
includes a protrusion portion 52a and a base portion 52b. The
protrusion portion 52a has a number of fins protruding from a
horizontal plane 52c defined by the base portion 52b. Fins of fin
structure 52 have sloped sidewalls. That is, in fin structure 52, a
surface of a sidewall of a given one of the fins is not parallel to
a surface of an opposing sidewall of an immediately adjacent fin.
Further, a surface of a sidewall of a given one of the fins is not
perpendicular to the horizontal plane 52c. Referring to FIG. 2, due
to the sidewalls of the fins of protrusion portion 52a being
sloped, a spacing, or gap, between every two immediately adjacent
fins of protrusion portion 52a increases in a direction moving from
base portion 52b toward the distal ends of the fins of protrusion
portion 52a. In other words, due to the sloped sidewalls, a spacing
or gap between every two immediately adjacent fins is wider near
the distal ends of the fins (e.g., at the top as shown in FIG. 2)
than it is near the base of the fins (e.g., near the base portion
52b as shown in FIG. 2). Put differently, given the sloped
sidewalls, each of one or more fins of the protrusion portion 52a
has a tapered profile in a cross-sectional view (as shown in FIG.
2) with a first width near the distal end of the respective fin
being less than a second width at the base of the respective fin
near the base portion 52b. Moreover, as shown in FIG. 2, trenches,
i.e., where the protrusion portion 52a come in contact with the
base portion 52b, of fin structure 52 may be relatively flat or
horizontal with respect to the horizontal plane 52c. Alternatively,
although not shown in FIG. 2, the trenches of fin structure 52 may
be notched, e.g., shaped as V-shaped notches as those shown in FIG.
3.
[0044] Compared with the fin structure 51 of FIG. 1, fin structure
52 of FIG. 2 tends to improve the aerodynamics for better heat
transfer via convection by a fluid, e.g., air blown by one or more
fans, flowing between the fins. When temperature in the fins rises
and the fluid between the fins, whether flowing through or
stagnant, will be warmed up. Fin structure 51 of FIG. 1 tends to
have relatively less efficiency in heat transfer from the fins to
the fluid, e.g., air, at least for the corner air at the bottom of
the trenches in terms of pushing the air out of the protrusion
portion 51a. In contrast, fin structure 52 of FIG. 2 tends to have
relatively more efficiency in pushing air out of the bottom of the
trenches to come out of the protrusion portion 52a. The difference
in efficiency is in the order of several percentage points.
[0045] As shown in FIG. 3, in one embodiment, a fin structure 53 of
multiple straight fins of silicon-based heat dissipation device 101
includes a protrusion portion 53a and a base portion 53b. The
protrusion portion 53a has a number of fins protruding from a
horizontal plane 53c defined by the base portion 53b. Fins of fin
structure 53 have substantially straight and parallel sidewalls.
That is, in fin structure 53, a surface of a sidewall of a given
one of the fins is substantially parallel to a surface of an
opposing sidewall of an immediately adjacent fin. Further, a
surface of a sidewall of a given one of the fins is substantially
perpendicular to the horizontal plane 53c. Moreover, as shown in
FIG. 3, trenches, i.e., where the protrusion portion 53a come in
contact with the base portion 53b, of fin structure 53 are not flat
or horizontal with respect to the horizontal plane 53c. Rather,
different from fin structure 51 of FIG. 1, the trenches of fin
structure 53 are notched, e.g., shaped as V-shaped notches as those
shown in FIG. 3.
[0046] Fin structure 53 of FIG. 3 tends to have better heat
dissipation performance than that of fin structure 51 of FIG. 1,
but worse than that of fin structure 52 of FIG. 2 due to
aerodynamics, assuming each of fin structures 51, 52 and 53 has the
same amount of surface area for the sidewalls of the fins.
[0047] The silicon-based heat-dissipation device 101 shown in FIG.
4 can be fabricated from a piece of single-crystal silicon by
etching various structural shapes as shown in FIGS. 1-3. As shown
in FIG. 4, the silicon-based heat-dissipation device 101 has a base
portion 2 and a protrusion portion 1. The base portion 2 has a
first primary side (e.g., the side that faces up in FIG. 4) and a
second primary side (e.g., the side that faces down in FIG. 4)
opposite the first primary side. The protrusion portion 1 of the
silicon-based heat-dissipation device 101 is on the first primary
side of the base portion 2 and protrudes therefrom. In the example
shown in FIG. 4, the protrusion portion 1 includes multiple
straight fins. The multiple straight fins of the protrusion portion
1 may be spaced apart from each other by an equidistant spacing 11.
Additionally or alternatively, the protrusion portion 1 may include
pin fins and/or flared fins.
[0048] As shown in FIG. 5, there are several dimensions associated
with the silicon-based heat-dissipation device 101. T1 denotes a
thickness of the base portion 2 that is measured across the base
portion 2 in a direction parallel to the first primary side of the
base portion 2. T2 denotes a height of the protrusion portion 1, or
the fins of the protrusion portion 1, that is measured from the
first primary side of the base portion 2 in a direction
perpendicular to the first primary side of the base portion 2. T3
denotes a width of the spacing 11 between every two adjacent fins
of the protrusion portion 1. T4 denotes a thickness of each of the
fins of the protrusion portion 1, measured across a respective one
of the fins in a direction parallel to the first primary side of
the base portion 2.
[0049] In one embodiment, the ratio T2:T4 is a large number in
order to increase the surface area of the silicon-based
heat-dissipation device 101 in a small footprint of silicon base.
In order to achieve a high convective cooling in the silicon-based
heat-dissipation device 101, the ratio of T2:T4 is greater than
5:1. Similarly, the ratio T2:T1 is greater than 5:1. Moreover, in
one embodiment, T3 is greater than or equal to T4. These dimensions
and ratios provide an optimum performance of the silicon-based
heat-dissipation device 101. For example, if each of the dimensions
T3 and T4 is 100 microns with T2 being 500 microns and T1 being 100
microns, then the silicon-based heat-dissipation device 101 would
have a large amount of surface area in a compact form factor.
However, air flow through the spacing 11 between every two adjacent
fins of the protrusion portion 1 may be restricted due to small
gap, T3 to ineffectively remove all heat from silicon fin. To
maximize thermal convection by air flow through the spacing 11
between every two adjacent fins of the protrusion portion 1, in
various implementations the dimension T3 and air speed can be
increased to achieve quick removal of heat from the fins of the
silicon-based heat-dissipation device 101.
[0050] FIGS. 6-8 illustrate a device 100 in accordance with an
embodiment of the present disclosure. The following description
refers to FIGS. 6-8.
[0051] FIG. 6 shows the device 100 which is a monolithic structure
of IC chip or Silicon-On-Insulator (SOI) combined with the
silicon-based heat-dissipation device 101. Typically integrated
circuits are developed or laid-down on a primary side of a silicon
wafer, and then the backside of the silicon wafer opposite the
primary side is lapped to make a thin silicon IC chip. In one
embodiment, the silicon-based heat-dissipation device 101 is built
or attached to the backside of the IC or SOI chip to increase the
heat dissipation by increasing the surface area of the existing
backside of the IC or SOI structure. The silicon-based
heat-dissipation device 101 built on the backside of the IC or SOI
chip provides more than ten times (10.times.) of surface area to
dissipate heat from the integrated circuits by convection or forced
air, compared to conventional metal-based heat sinks or
radiators.
[0052] As shown in FIGS. 7 and 8, each of heat-generating devices
21-25 is embedded in or physically coupled, mounted or otherwise
attached to the second primary side of the base portion 2. Each of
heat-generating devices 23 and 25 may be an embedded or doped
integrated circuit while each of heat-generating devices 21, 22 and
24 may be a driver chip, microprocessor, graphics processor, memory
chip, GPS chip, communications chip, laser diode (edge-emitting or
VCSEL), LED, photodiode, sensor or the like. Regardless what the
case may be, each of heat-generating devices 21-25 generates heat
when powered on for which heat needs to be removed to prolong the
operational life and enhance the performance of the heat-generating
devices 21-25. One of ordinary skill in the art would appreciate
that, although multiple heat-generating devices are shown in FIGS.
7 and 8, in various embodiments the number of heat-generating
devices may be more or less depending on the actual
implementation.
[0053] FIGS. 9 and 10 illustrate a device 200 in accordance with
another embodiment of the present disclosure. The following
description refers to FIGS. 9 and 10.
[0054] The device 200 and the device 100 are similar in many ways.
In the interest of brevity, detailed description of differences
between the device 200 and the device 100 is provided herein while
similarity therebetween is not repeated. As shown in FIGS. 9 and
10, the device 200 includes a silicon-based heat-dissipation device
102 that has a base portion 6 and a protrusion portion 5. The base
portion 6 has a first primary side and a second primary side
opposite the first primary side. The protrusion portion 5 is on the
first primary side of the base portion 6 and protrudes therefrom.
The protrusion portion 5 may include multiple fins similar to those
of the protrusion portion 1 of the silicon-based heat-dissipation
device 101, and thus detailed description thereof is not
repeated.
[0055] The silicon-based heat-dissipation device 102 includes a
slit 12 on the base portion 6 that cuts off, or severs, a
direct-line thermal coupling path via conduction through the base
portion 6 between a first heat-generating device on one side of the
slit 12 and a second heat-generating device on the other side of
the slit 12. In one embodiment, the slit 12 may be an L-shaped slit
as shown in FIGS. 9 and 10. In other embodiments, instead of a
slit, the base portion 6 may include a trench or groove on its
first primary side or second primary side.
[0056] In the example shown in FIG. 10, each of heat-generating
devices 26-29 is embedded in or physically coupled, mounted or
otherwise attached to the second primary side of the base portion
6. As shown in FIG. 10, the heat-generating device 26 is on one
side of the L-shaped slit 12 while the heat-generating devices
26-28 are on the other side the L-shaped slit 12. The slit 12
provides the function of severing a direct-line thermal coupling
path via conduction through the base portion 6 between the
heat-generating device 26 and each of the heat-generating devices
27-29. This way, the absolute temperature of each of the
heat-generating device 27-29 can be lowered. This arrangement may
be suitable, for example, when the heat-generating device 26 (e.g.,
a microprocessor) generates more heat than each of the
heat-generating devices 27-29 during operation. The silicon-based
heat-dissipation device 102 may be fabricated on the backside of an
IC or SOI chip.
[0057] In summary, according to one aspect of the present
disclosure, an apparatus may include a silicon-based
heat-dissipation device. The silicon-based heat-dissipation device
may include a base portion and a protrusion portion. The base
portion may have a first primary side and a second primary side
opposite the first primary side. The protrusion portion may be on
the first primary side of the base portion and may protrude
therefrom. The second primary side of the base portion may be
configured to have one or more heat-generating devices embedded
therein or physically coupled thereto such that at least a portion
of heat generated by the one or more heat-generating devices is
dissipated to the silicon-based heat-dissipation device by
conduction.
[0058] In at least one embodiment, the base portion may include a
slit that communicatively connects the first primary side and the
second primary side of the base portion.
[0059] In at least one embodiment, when each of more than one
heat-generating devices is embedded in or physically coupled to the
base portion, at least a first heat-generating device of the more
than one heat-generating devices may be on a first side of the slit
and at least a second heat-generating device of the more than one
heat-generating devices may be on a second side of the slit
opposite the first side of the slit such that the slit severs a
direct-line thermal coupling path via conduction through the base
portion between the first and the second heat-generating
devices.
[0060] In at least one embodiment, the slit may include an L-shaped
slit.
[0061] In at least one embodiment, the protrusion portion of the
silicon-based heat-dissipation device may include a plurality of
fins.
[0062] In at least one embodiment, the plurality of fins may
include a plurality of straight fins.
[0063] In at least one embodiment, a ratio of a height of the fins,
measured from the first primary side of the base portion in a
direction perpendicular to the first primary side, to a thickness
of each of the fins, measured across a respective one of the fins
in a direction parallel to the first primary side of the base
portion, may be greater than 5:1.
[0064] In at least one embodiment, a ratio of a height of the fins,
measured from the first primary side of the base portion in a
direction perpendicular to the first primary side, to a thickness
of the base portion, measured across the base portion in a
direction parallel to the first primary side of the base portion,
may be greater than 5:1.
[0065] In at least one embodiment, a spacing between every two fins
of the fins, measured between respective two fins of the fins in a
direction parallel to the first primary side of the base portion,
may be greater than or equal to a thickness of each of the fins,
measured across a respective one of the fins in the direction
parallel to the first primary side of the base portion.
[0066] In at least one embodiment, the plurality of fins may
include a plurality of pin fins.
[0067] In at least one embodiment, the plurality of fins may
include a plurality of flared fins.
[0068] In at least one embodiment, the apparatus may further
include one or more integrated circuits embedded in the second
primary side of the base portion or one or more electrically-driven
devices physically coupled to the second primary side of the base
portion.
[0069] In at least one embodiment, the apparatus may further
include one or more integrated circuits embedded in the second
primary side of the base portion or one or more electrically-driven
devices physically coupled to the second primary side of the base
portion. At least a first one of the one or more integrated
circuits or the one or more electrically-driven devices may be on a
first side of the slit. At least a second one of the one or more
integrated circuits or the one or more electrically-driven devices
may be on a second side of the slit opposite the first side of the
slit. The slit may sever a direct-line thermal coupling path via
conduction through the base portion between the first one of the
one or more integrated circuits or the one or more
electrically-driven devices and the second one of the one or more
integrated circuits or the one or more electrically-driven
devices.
[0070] In at least one embodiment, the silicon-based
heat-dissipation device may be made of single-crystal silicon.
[0071] According to another aspect, an apparatus may include a
silicon-based heat-dissipation device. The silicon-based
heat-dissipation device may include a base portion and a protrusion
portion. The base portion may have a first primary side and a
second primary side opposite the first primary side. The protrusion
portion may be on the first primary side of the base portion and
protruding therefrom. The protrusion portion may include a
plurality of fins. Each of at least two immediately adjacent fins
of the fins of the protrusion portion may have a tapered profile in
a cross-sectional view with a first width near a distal end of the
respective fin being less than a second width at a base of the
respective fin near the base portion of the heat-dissipation
device.
[0072] In at least one embodiment, the second primary side of the
base portion may be configured to have one or more heat-generating
devices embedded therein or physically coupled thereto such that at
least a portion of heat generated by the one or more
heat-generating devices is dissipated to the silicon-based
heat-dissipation device by conduction.
[0073] In at least one embodiment, a trench between the at least
two immediately adjacent fins may have a relatively flat surface
with respect to a horizontal plane defined by the first primary
side of the base portion.
[0074] In at least one embodiment, a trench between the at least
two immediately adjacent fins may have a V-shaped notch with
respect to a horizontal plane defined by the first primary side of
the base portion.
[0075] In at least one embodiment, the apparatus may further
include one or more integrated circuits embedded in the second
primary side of the base portion or one or more electrically-driven
devices physically coupled to the second primary side of the base
portion. The base portion may include a slit that communicatively
connects the first primary side and the second primary side of the
base portion. At least a first one of the one or more integrated
circuits or the one or more electrically-driven devices may be on a
first side of the slit. At least a second one of the one or more
integrated circuits or the one or more electrically-driven devices
may be on a second side of the slit opposite the first side of the
slit. The slit may sever a direct-line thermal coupling path via
conduction through the base portion between the first one of the
one or more integrated circuits or the one or more
electrically-driven devices and the second one of the one or more
integrated circuits or the one or more electrically-driven
devices.
[0076] In at least one embodiment, the silicon-based
heat-dissipation device may be made of single-crystal silicon.
Additional and Alternative Implementation Notes
[0077] The above-described embodiments pertain to a technique,
design, scheme, device and mechanism for isolation of thermal
ground for multiple heat-generating devices on a substrate.
Although the embodiments have been described in language specific
to certain applications, it is to be understood that the appended
claims are not necessarily limited to the specific features or
applications described herein. Rather, the specific features and
applications are disclosed as example forms of implementing such
techniques.
[0078] In the above description of example implementations, for
purposes of explanation, specific numbers, materials
configurations, and other details are set forth in order to better
explain the invention, as claimed. However, it will be apparent to
one skilled in the art that the claimed invention may be practiced
using different details than the example ones described herein. In
other instances, well-known features are omitted or simplified to
clarify the description of the example implementations.
[0079] The described embodiments are intended to be primarily
examples. The described embodiments are not meant to limit the
scope of the appended claims. Rather, the claimed invention might
also be embodied and implemented in other ways, in conjunction with
other present or future technologies.
[0080] Moreover, the word "example" is used herein to mean serving
as an example, instance, or illustration. Any aspect or design
described herein as "example" is not necessarily to be construed as
preferred or advantageous over other aspects or designs. Rather,
use of the word example is intended to present concepts and
techniques in a concrete fashion. The term "techniques," for
instance, may refer to one or more devices, apparatuses, systems,
methods, articles of manufacture, and/or computer-readable
instructions as indicated by the context described herein.
[0081] As used in this application, the term "or" is intended to
mean an inclusive "or" rather than an exclusive "or." That is,
unless specified otherwise or clear from context, "X employs A or
B" is intended to mean any of the natural inclusive permutations.
That is, if X employs A; X employs B; or X employs both A and B,
then "X employs A or B" is satisfied under any of the foregoing
instances. In addition, the articles "a" and "an" as used in this
application and the appended claims should generally be construed
to mean "one or more," unless specified otherwise or clear from
context to be directed to a singular form.
* * * * *