U.S. patent application number 13/858372 was filed with the patent office on 2013-08-22 for thermal conduction device and method for fabricating the same.
This patent application is currently assigned to RITEDIA CORPORATION. The applicant listed for this patent is Ritedia Corporation. Invention is credited to Shao-Chung HU, Hsing HUNG, Hung-Cheng LIN, I-Chiao LIN, Chien-Min SUNG.
Application Number | 20130216823 13/858372 |
Document ID | / |
Family ID | 46019898 |
Filed Date | 2013-08-22 |
United States Patent
Application |
20130216823 |
Kind Code |
A1 |
HU; Shao-Chung ; et
al. |
August 22, 2013 |
THERMAL CONDUCTION DEVICE AND METHOD FOR FABRICATING THE SAME
Abstract
A thermal conduction device and a method for fabricating the
same are disclosed. Firstly, arrange a plurality of diamond
particles on a plane according to a. predetermined pattern to form
a diamond particle monolayer. Next, apply a forming process on a
metal material such that the metal material forms a metal matrix
wrapping the diamond particles to form a composite body including
the diamond particle monolayer embedded in the metal matrix. Next,
stack a plurality of the composite bodies and perform a heating
process to join the metal matrixes to each other to form the
thermal. conduction device. The device is characterized in
arranging diamond particles on a plane to form a two-dimensional
monolayer structure and manufactured via assembling the
two-dimensional monolayer structures to form a three-dimensional
multilayer structure. By controlling the arrangement of the diamond
particles, the thermal conduction device can have superior thermal
conduction performance.
Inventors: |
HU; Shao-Chung; (Xindian
City, TW) ; HUNG; Hsing; (Sanxia Township, TW)
; LIN; Hung-Cheng; (Yingge Township, TW) ; LIN;
I-Chiao; (Taipei City, TW) ; SUNG; Chien-Min;
(Danshui Township, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ritedia Corporation; |
|
|
US |
|
|
Assignee: |
RITEDIA CORPORATION
Hsinchu
TW
|
Family ID: |
46019898 |
Appl. No.: |
13/858372 |
Filed: |
April 8, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13004437 |
Jan 11, 2011 |
8453916 |
|
|
13858372 |
|
|
|
|
Current U.S.
Class: |
428/323 |
Current CPC
Class: |
B32B 5/16 20130101; H01L
23/3733 20130101; B32B 2264/10 20130101; H01L 2924/0002 20130101;
Y10T 428/25 20150115; H01L 23/3732 20130101; B32B 15/20 20130101;
H01L 2924/00 20130101; H01L 2924/0002 20130101; H01L 23/3736
20130101; B32B 2307/302 20130101; C09K 5/00 20130101 |
Class at
Publication: |
428/323 |
International
Class: |
C09K 5/00 20060101
C09K005/00; B32B 5/16 20060101 B32B005/16 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 4, 2010 |
TW |
099137898 |
Claims
1. A thermal conduction device comprising a metal matrix; and a
plurality of diamond particle monolayers embedded in the metal
matrix and each containing a plurality of diamond particles
arranged on a plane according to a predetermined pattern.
2. The thermal conduction device according to claim 1, wherein the
diamond particles are horizontally spaced by a first distance.
3. The thermal conduction device according to claim 1, wherein the
diamond particles horizontally contact with each other.
4. The thermal conduction device according to claim 1, wherein the
diamond particle monolayers are vertically spaced by a second
distance.
5. The thermal conduction device according to claim 1, wherein the
diamond particles have a diameter of 20-1000 .mu.m.
6. The thermal conduction device according to claim 1, wherein the
diamond particles have a volume percent of 20-70% with respect to
the metal matrix.
7. The thermal conduction device according to claim 6, wherein the
diamond particles have a volume percent of 30-50% with respect to
the metal matrix.
8. The thermal conduction device according to claim 1, wherein the
metal matrix is made of a material selected from a group consisting
of copper, aluminum, iron, cobalt, chromium and nickel.
9. The thermal conduction device according to claim 1, having a
thermal conductivity of 200-900 W/mk.
10. The thermal conduction device according to claim 1, having a
thermal expansion coefficient of 2-10 ppm/K.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Divisional of co-pending application
Ser. No. 13/004,437, filed on Jan. 11, 2011, for which priority is
claimed under 35 U.S.C. .sctn.120; and this application claims
priority of Application No. 099137898 filed in Taiwan, on Nov. 4,
2010 under 35 .sctn.119, the entire contents of all of which are
hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a thermal conduction device
and a method for fabricating the same, particularly to a method for
fabricating a thermal conduction device, which can easily control
arrangement of diamond particles in a metal matrix, and a thermal
conduction device fabricated by the method.
BACKGROUND OF THE INVENTION
[0003] Thermal conduction has long been a critical factor
influencing the performance and development direction of electronic
products. For example, the chip of a computer usually carries a
great quantity of transistors. Under the tendency of fabricating
slim and lightweight electronic products, more and more transistors
are crowded into smaller and smaller space, which makes heat hard
to dissipate. LED (Light Emitting Diode) has been extensively
applied to illumination recently. LED emits light with a great
amount of heat generated simultaneously. If heat cannot be removed
effectively, the service life of LED will be obviously shortened.
Therefore, thermal conduction performance would influence the
development of high power LEI).
[0004] There have been many techniques developed to overcome the
abovementioned thermal conduction problems of electronic products.
Diamond materials have the advantages of high thermal conductivity
and low thermal expansion coefficient. Therefore, manufacturers
have paid much attention to develop thermal conduction devices
containing diamond material. For example, U.S. Pat. No. 6,987,318
disclosed a diamond composite heat spreader having thermal
conductivity gradients and associated methods. The heat spreader
consists of diamond particles and a braze alloy wrapping the
diamond particles, wherein the varied diamond concentration
generates thermal conductivity gradient, and wherein the area near
the heat source has higher thermal conductivity. Thereby, the
consumption of diamond particles is reduced. In fabrication,
diamond particles having different particle sizes are sequentially
arranged in a mold, and an interstitial material is filled into the
gaps. Then, the interstitial material and the diamond particles are
integrated via sintering, diffusion or electrodeposition.
[0005] US patent publication No. US 2005/0189647 disclosed a
carbonaceous composite heat spreader and associated methods,
wherein graphite and diamond particles are distributed in an
aluminum matrix. Graphite can increase isotropy of thermal
conduction in the spreader. In fabrication, a graphite layer is
placed in a mold, and then a layer of diamond grits is stacked over
the graphite layer. The layer of diamond grits is formed via
bonding diamond particles with a binder. The stacking of a graphite
layer and the c is repeated several times. Then, molten aluminum or
molten aluminum alloy is poured into the mold. After
solidification, the heat spreader is obtained.
[0006] In U.S. Pat. No. 6,987,318, diamond particles are stacked in
a three-dimensional structure beforehand. Next, the
three-dimensional structure is placed in a mold, and the
interstitial material is filled into the voids. However, the
filling of the interstitial material is likely to alter the
three-dimensional arrangement of diamond particles. Thus,
performance of the heat spreader usually deviates from expectation.
Besides, there is difference between the thermal expansion
coefficients of the diamond particles and the filling material,
which impairs the fabrication of a large-area heat spreader. In US
patent publication No. US 2005/0189647, graphite layers and layers
of diamond grits also need stacking in a three-dimensional
structure in advance. Therefore, the same problem also occurs.
SUMMARY OF THE INVENTION
[0007] The primary objective of the present invention is to
overcome the problems occurring in the conventional methods for
fabricating a thermal conduction device, including the problem that
arrangement of diamond particles is hard to control, the problem
that difficult to control the desired thermal conductivity and the
problem that difference between the thermal expansion coefficients
of different materials impairs the fabrication of a large-size
thermal conduction. device.
[0008] To achieve the abovementioned objective, the present
invention proposes a method of fabricating a thermal conduction
device, which comprises steps:
[0009] (a) arranging a plurality of diamond particles on a plane
according to a predetermined pattern to form a diamond particle
monolayer;
[0010] (b) applying a forming process on a metal material such that
the metal material forms a metal matrix wrapping the diamond
particles to obtain a composite body containing the diamond
particle monolayer embedded in the metal matrix; and
[0011] (c) stacking a plurality of the composite bodies and
applying a heating process to join the metal matrixes to each
other.
[0012] Another objective of the present invention is to overcome
the problem that poor arrangement of diamond particles makes
thermal properties hard to control in the conventional thermal
conduction device.
[0013] Tb achieve the abovementioned objective, the present
invention further proposes a thermal conduction device, which
comprises a metal matrix and a plurality of diamond particle
monolayers, wherein the diamond particle monolayers are embedded in
the metal matrix, and wherein each diamond particle monolayer
includes a plurality of diamond particles arranged on a plane
according to a predetermined pattern.
[0014] Compared with the conventional techniques, the thermal
conduction device and the method for fabricating the same of the
present invention have the following advantages:
[0015] 1. The three-dimensional multilayer structure is formed via
assembling a plurality of composite bodies each containing a
two-dimensional diamond particle monolayer in the present
invention. The thermal conductivity of the composite body can be
controlled via modifying the arrangement of diamond particles in
the diamond particle monolayers. Thereby, the thermal conduction
device, which is formed via assembling together a plurality of
composite bodies, can attain the desired thermal conductivity. For
example, if the diamond particle facets having the maximum area are
all oriented to an identical direction, the thermal conductivity
will reach the maximum value in the direction.
[0016] 2. The thermal expansion coefficients of the composite
bodies can be adjusted to be within a narrow range via modifying
the arrangement of diamond particles in the diamond particle
monolayers. Thus, the difference of the thermal expansion
coefficients between the diamond particles and the metal matrix
would not restrict the final size of the thermal conduction device
since the composite bodies can have similar values of thermal
expansion coefficients. Therefore, the present invention favors
fabrication of large-size thermal conduction devices.
[0017] 3. Through varying the connection manner of the composite
bodies, the structural design of the thermal conduction device is
more flexible in the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIGS. 1A-1G are diagrams schematically showing the process
of a method for fabricating a thermal conduction device according
to a first embodiment of the present invention;
[0019] FIGS. 2A-2F are diagrams schematically showing the process
of a method for fabricating a thermal conduction device according
to a second embodiment of the present invention;
[0020] FIGS. 3A-3E are diagrams schematically showing the process
of a method for fabricating a thermal conduction device according
to a third embodiment of the present invention; and
[0021] FIGS. 4A-4C are diagrams schematically showing the process
of a method for fabricating a thermal conduction device according
to a fourth embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0022] Below are described in detail the technical contents of the
thermal conduction device and the method for fabricating the same
of the present invention.
[0023] Refer to FIGS. 1A-1G diagrams schematically showing the
process of a method for fabricating a thermal conduction device
according to a first embodiment of the present invention. Firstly,
arrange a plurality of diamond particles 21 on a plane X according
to a predetermined pattern to form a diamond particle monolayer 20.
In the beginning, provide a mold including an upper mold 91, a
middle mold 92 and a lower mold 93. The diamond particles 21 are
arranged on the plane X inside the mold to obtain the diamond
particle monolayer 20. In this embodiment, the diamond particles 21
are arranged horizontally and equidistantly spaced by a first
distance, as shown in FIG. 1A. However, the present invention does
not limit that the diamond particles 21 are arranged in such a way.
The diamond particles 21 may be arranged in another way according
to practical design requirement. For example, the first distance is
controlled to be zero to make the diamond particles 21 contact with
each other and attain the closest horizontal arrangement. The
diamond particles 21 have a diameter of 20-1000 .mu.m. The first
distance and the diameter of diamond particles 21 may be varied
according to practical design requirement.
[0024] Next, cover one side of the diamond particle monolayer 20
with a first metal material 10, as shown in FIG. 1B. Following, use
the upper mold 91 to perform a first pre-pressing step on the first
metal material 10. Then flip over the mold and remove the lower
mold 93, as shown in FIG. 1C. Next, place a second metal material
30 on another side of the diamond particle monolayer 20 to obtain a
metal material 40 including the first metal material 10 and the
second metal material 30, as shown in FIG. 1D. In this embodiment,
both the first metal material 10 and the second metal material 30
are in form of metal powder made of an identical pure metal
material, such as copper, aluminum, iron, cobalt, chromium, nickel,
or an alloy thereof.
[0025] Next, apply a forming process on the metal material 40. The
forming process may be a hot pressing process or a direct pressing
process. The hot pressing process may be carried out in a vacuum
environment or in a specified atmosphere with the metal material 40
being pressed by a load or by the mold. Alternatively, the hot
pressing process may be realized with an SPS (Spark Plasma
Sintering) process. Before the hot pressing process, a second pre-
pressing step may be carried out with the upper mold 91 or the
lower mold 93. In this embodiment, the forming process is realized
with the SPS process at a temperature slightly lower than the
melting point of the metal material 40. After the forming process,
the metal material 40 forms a metal matrix 50 wrapping the diamond
particles 21. Thus is obtained a composite body 60 with the diamond
particle monolayer 20 maintained on the plane X and embedded in the
metal matrix 50, as shown in FIG. 1E. In this embodiment, the metal
material 40 has a thickness greater than that of the diamond
particle monolayer 20 lest the diamond particles 21 outcrop from
the metal matrix 50.
[0026] Next, stack up a plurality of the composite bodies 60. In
this embodiment, one composite body 60 is stacked on the top of the
other composite body 60, as shown in FIG. 1F. However, the present
invention does not limit the number of the composite bodies 60
stacked together. Alternatively, the composite bodies 60 may be
assembled edge by edge. Following, perform a heating process to
join the metal matrixes 50. A pressing process may be undertaken
simultaneously with the heating process. The heating process may be
carried out in a vacuum environment or under a specified
atmosphere. Alternatively, the heating process may be realized with
an SPS process. In this embodiment, the heating process is carried
out through the SPS process at a temperature slightly lower than
the melting point of metal matrix 50.
[0027] Refer to FIG. 1G. After the heating process, a thermal
conduction device 70 including the metal matrix 50 and a plurality
of the diamond particle monolayers 20 is obtained, wherein the
diamond particle monolayers 20 are embedded in the metal matrix 50,
and wherein the diamond particles 21 are arranged on the planes X
and spaced by the first distance according to a predetermined
pattern. Besides, two adjacent diamond particle monolayers 20 are
vertically spaced by a second distance. In the present invention,
the thermal conductivity of the thermal conduction device 70 is
controlled to be 200-900 W/mk, and the thermal expansion
coefficient is controlled to be 2-10 ppm/K. In the present
invention, the diamond particles 21 have a volume percent of 20-70%
with respect to the metal matrix 50, and 30-50% v/v is
preferred.
[0028] In this embodiment, copper is used as the first metal
material 10 and the second metal material 30; the SPS process is
used as the forming process and the heating process is undertaken
at a temperature of 900-1050.degree. C. with a pressing pressure of
10-40 MPa. A sintering promoter may be added into the metal
material 40 to improve joining of metal powder. The sintering
promoter may be titanium, chromium, nickel, or a mixture thereof
The present invention does not restrict the fabrication parameters
of the thermal conduction device, such as the sintering
temperature, the temperature rising rate, the holding time, the
atmosphere, the pressing pressure and the sintering promoter. The
abovementioned fabrication parameters depend on the metal material
40 and the quantity, arrangement and morohology of the diamond
particles 21.
[0029] Refer to FIGS. 2A-2F diagrams schematically showing the
process of a method for fabricating a thermal conduction device
according to a second embodiment of the present invention, Firstly,
place a first metal material 10 in a mold. The first metal material
10 is in form of metal powder. Next, arrange diamond particles 21
on the first metal material 10 with a first distance therebetween
according to a predetermined pattern to form a diamond particle
monolayer 20, as shown in FIG. 2B. In this embodiment, an adhesive
layer is used to fix the diamond particles 21. The adhesive layer
is made of PVA (or PVAC) (polyvinyl acetate), PEG (polyethylene
glycol), or the like. Following, place a second metal material 30
on the diamond particle monolayer 20 to obtain a metal material 40
including the first metal material 10 and the second metal material
30, as shown in FIG. 2C. The second metal material 30 is also in
form of metal powder. The first metal material 10 and the second
metal material 30 are made of the same pure metal, such as copper,
aluminum, iron, cobalt, chromium, nickel, or an alloy thereof, and
copper is preferred.
[0030] Next, perform a forming process to sinter the metal material
40 into a metal matrix 50. Next, remove the mold to obtain a
composite body 60, as shown in FIG. 2D. Then, stack a plurality of
the composite bodies 60, as shown in FIG. 2E. Following, perform a
heating process to obtain a thermal conduction device 70, as shown
in FIG. 2F. In the second embodiment, the SPS process is also used
as the forming process and the heating process is carried out at a
temperature slightly lower than the melting point of the metal
material 40. In the second embodiment, a sintering promoter may be
added into the metal material 40 to improve joining of metal
powder. The sintering promoter may be titanium, chromium, nickel,
or a mixture thereof. In the second embodiment, the second metal
material 30 has a thickness greater than that of the diamond
particle monolayer 20 lest the diamond particles outcrop from the
metal matrix 50.
[0031] Refer to FIGS. 3A-3E diagrams schematically showing the
process of a method for fabricating a thermal conduction device
according to a third embodiment of the present invention. In the
third embodiment, both the first metal material 10 and the second
metal material 30 are in form of a metal plate made of copper,
aluminum, iron, cobalt, chromium, nickel, or an alloy thereof, and
copper is preferred. Firstly, provide the first metal material 10.
Next, place diamond particles 21 on the first metal material 10
such that the diamond particles 21 are arranged on a plane X
according to a predetermined pattern to form a diamond particle
monolayer 20. In the third embodiment, the diamond particles 21
contact with each other, as shown in FIG. 3B.
[0032] Next, place the second metal material 30 over the diamond
particle monolayer 20 to obtain a metal material 40 including the
first metal material 10 and the second metal material 30, as shown
in FIG. 3C and FIG. 3D. In the third embodiment, the first metal
material 10 and the second metal material 30 are made of the same
metal, and copper is preferred. Next, apply a forming process on
the metal material 40 such that the metal material 40 forms a metal
matrix 50 to obtain a composite body 60 including the diamond
particle monolayer 20 embedded in the metal matrix 50 with the
diamond particles 21 maintained on the plane X, as shown in FIG.
3E. Next, similarly to the processes shown in FIG. 1F and FIG. 1G,
stack a plurality of the composite bodies 60 and perform a heating
process to join the metal matrixes 50 to each other. In the heating
process, a pressing process may be carried out simultaneously. In
the third embodiment, the SPS process is also used as the forming
process and the heating process is undertaken at a temperature
slightly lower than the melting point of the metal material 40.
[0033] Refer to FIGS. 4A-4C diagrams schematically showing the
process of a method for fabricating a thermal conduction device
according to a fourth embodiment of the present invention. In the
fourth embodiment, a diamond particle monolayer 20 is interposed
between two composite bodies 60. Firstly, arrange diamond particles
21 on the surface of a composite body 60 according to a
predetermined pattern to form a diamond particle monolayer 20, as
shown in FIG. 4A. Next, stack another composite body 60 over the
diamond particle monolayer 20, as shown in FIG. 4B. Then perform a
heating process to obtain a thermal conduction device 70, as shown
in FIG. 4C.
[0034] In conclusion, the thermal conduction device and the method
for fabricating the same of the present invention are characterized
in arranging diamond particles on a plane to form a two-dimensional
monolayer structure and assembling the two-dimensional monolayer
structures to form a three-dimensional multilayer structure. The
configuration, volume and spacing of diamond particles can be more
easily obtained via arranging diamond particles to form the diamond
particle monolayer. Therefore, the present invention adjusts the
related parameters configuration, volume and spacing) in diamond
particle monolayers in advance and then assembles the composite
bodies containing the diamond particle monolayers to obtain a
thermal conduction device with the thermal conductivity thereof
being accurately controlled to achieve an optimized heat conduction
performance. In one embodiment, the hexoctahedron diamond particles
are arranged to let the facets having the greatest area face toward
a same direction (such as toward a heat source) to make the thermal
conduction device have a higher thermal conductivity in a specified
direction.
[0035] Further, the present invention can respectively adjust the
thermal expansion coefficients of the composite bodies to reduce
difference of the thermal expansion coefficients between the
composite bodies, Whereby the composite bodies can be more easily
joined to fabricate a large-size thermal conduction device.
Furthermore, the present invention can join the composite bodies in
various ways to diversify the design of thermal conduction
devices.
[0036] The embodiments described above are only to exemplify the
present invention but not to limit the scope of the present
invention. Any equivalent modification or variation according to
the spirit of the present invention is to be also included within
the scope of the present invention.
* * * * *