U.S. patent application number 13/971577 was filed with the patent office on 2013-12-19 for heat-dissipation unit coated with oxidation-resistant nano thin film and method of depositing the oxidation-resistant nano thin film thereof.
This patent application is currently assigned to Asia Vital Components Co., Ltd.. The applicant listed for this patent is Asia Vital Components Co., Ltd.. Invention is credited to Ying-Tung Chen.
Application Number | 20130333864 13/971577 |
Document ID | / |
Family ID | 44186035 |
Filed Date | 2013-12-19 |
United States Patent
Application |
20130333864 |
Kind Code |
A1 |
Chen; Ying-Tung |
December 19, 2013 |
Heat-Dissipation Unit Coated with Oxidation-Resistant Nano Thin
Film and Method of Depositing the Oxidation-Resistant Nano Thin
Film Thereof
Abstract
A heat-dissipation unit coated with oxidation-resistant nano
thin film includes a metal main body having a heat-absorbing
portion and a heat-dissipating portion, both of which are coated
with at least a nano metal compound thin film. To form the nano
metal compound thin film on the heat-dissipation unit, first form
at least a nano compound coating on an outer surface of the
heat-dissipation unit, and then supply a reduction gas into a
high-temperature environment to perform a heat treatment and a
reduction process on the heat-dissipation unit and the nano
compound coating thereof, and finally, a nano metal compound thin
film is formed on the surface of the heat-dissipation unit after
completion of the heat treatment and the reduction process. With
the nano metal compound thin film, the heat-dissipation unit is
protected against formation of oxide on its surface and accordingly
against occurrence of increased thermal resistance thereof.
Inventors: |
Chen; Ying-Tung; (Taoyuan
City, TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Asia Vital Components Co., Ltd. |
Sinjhuang City |
|
TW |
|
|
Assignee: |
Asia Vital Components Co.,
Ltd.
Sinjhuang City
TW
|
Family ID: |
44186035 |
Appl. No.: |
13/971577 |
Filed: |
August 20, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12938334 |
Nov 2, 2010 |
|
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|
13971577 |
|
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Current U.S.
Class: |
165/104.26 |
Current CPC
Class: |
H01L 23/36 20130101;
C23C 18/1295 20130101; F28D 15/0275 20130101; B82Y 30/00 20130101;
F28D 15/04 20130101; F28F 2245/00 20130101; H01L 23/427 20130101;
H01L 2924/0002 20130101; C23C 18/1216 20130101; H01L 2924/0002
20130101; H05K 13/00 20130101; F28D 15/0233 20130101; C23C 18/1212
20130101; C23C 18/1204 20130101; C23C 18/1254 20130101; H01L 23/473
20130101; H01L 2924/00 20130101 |
Class at
Publication: |
165/104.26 |
International
Class: |
F28D 15/04 20060101
F28D015/04 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 29, 2009 |
TW |
098145478 |
Claims
1-6. (canceled)
7. A heat-dissipation unit coated with oxidation-resistant nano
thin film, comprising a metal main body internally defining a
chamber; the chamber being provided on an interior surface with a
wick structure, and the wick structure being coated with at least a
nano metal compound thin film.
8. The heat-dissipation unit coated with oxidation-resistant nano
thin film as claimed in claim 7, wherein the heat-dissipation unit
is selected from the group consisting of a uniform temperature
plate, a heat pipe, a flat heat pipe, a loop heat pipe, and a water
block.
9. The heat-dissipation unit coated with oxidation-resistant nano
thin film as claimed in claim 8, wherein the nano metal compound
thin film is formed via a reaction of a reduction gas with at least
a nano compound coating and the wick structure.
10. The heat-dissipation unit coated with oxidation-resistant nano
thin film as claimed in claim 9, wherein the nano compound coating
is formed of a material selected from the group consisting of
nitride, carbide, sulfide, and oxide.
11. The heat-dissipation unit coated with oxidation-resistant nano
thin film as claimed in claim 10, wherein the oxide is selected
from the group consisting of SiO.sub.2, TiO.sub.2, Al.sub.2O.sub.3,
ZrO.sub.2, CaO, K.sub.2O, and ZnO.
12. The heat-dissipation unit coated with oxidation-resistant nano
thin film as claimed in claim 7, wherein the metal main body is
formed of a material selected from the group consisting of copper,
aluminum, nickel, and stainless steel.
13-19. (canceled)
Description
[0001] This application claims the priority benefit of Taiwan
patent application number 098145478 filed on Dec. 29, 2009.
FIELD OF THE INVENTION
[0002] The present invention relates to a heat-dissipation unit
coated with oxidation-resistant nano thin film and a method of
depositing the oxidation-resistant nano thin film on the
heat-dissipation unit.
BACKGROUND OF THE INVENTION
[0003] When an electronic device operates, electronic elements
inside the device would produce heat. The heat is produced mainly
by an operating chip during operation thereof. With the constantly
increased performance thereof, the chip's power is now close to
100W and the temperature thereof would exceed 100.degree. C. if no
proper heat dissipation mechanism is provided.
[0004] The currently used chips are usually made of a semiconductor
material, such as silicon. Since a chip internally includes a large
quantity of metal wires and insulating thin films, and the thermal
expansion coefficient of the metal wire material might be several
times as high as that of the insulating material, the chip would
usually crack and become damaged when it continuously works at a
temperature higher than 90.degree. C.
[0005] To prevent the chip from overheat and burnout, waste heat
produced by electric current must be removed from the electronic
elements as soon as possible. To quickly remove the produced heat
from the chip, the chip is usually arranged to contact with a
copper sheet or is embedded in a metal-based ceramic sintered body,
such as aluminum-based silicon carbide, which has high thermal
conductivity. In addition, a heat-dissipation unit is needed to
help increasing the heat dissipation efficiency, so as to avoid an
overheated and burnt-out chip. The heat-dissipation unit is mainly
a radiating fin assembly, a heat sink or a heat pipe. A cooling fan
can also be used to assist in forced convection, in order to
achieve desired heat dissipating and cooling effects.
[0006] A metal-made heat radiating fin exposed to air would
gradually become oxidized to result in electrical potential
difference in the radiating fin. Such internal electrical potential
difference would in turn cause electrochemical reaction to form
metal oxide on the radiating fin. A metal oxide has a thermal
conducting efficiency much lower than that of a pure metal, and
would therefore largely reduce the heat dissipating effect and
thermal conducting efficiency of the metal radiating fin. When the
oxidation becomes worse, the oxidized metal oxide having loose
structure tends to peel off from the metal surface of the radiating
fin to contaminate the chip in contact with the radiating fin.
[0007] Further, an oxidized metal surface would change in color to
adversely affect the appearance of the metal material.
[0008] And, a metal radiating fin formed through metal (such as
copper or aluminum) powder sintering process and having a porous
structure tends to more easily have reduced heat dissipation
performance due to oxidation. To prevent oxidation, the metal
radiating fin is usually externally coated with a layer of nickel
or tin through a water solution process. The nickel can be coated
on the radiating fin in different ways, including electroplating
and chemical plating (electroless plating). However, the coating
obtained through the water solution process is easily subjected to
contamination, such as adsorption of acid group anions, which would
corrode the semiconductor packaging.
[0009] Further, the nickel coating or the tin coating usually has
thermal conducting efficiency much lower than that of the
frequently used copper radiating fin, and would therefore have
adverse influence on the heat dissipating effect of copper.
[0010] It is therefore tried by the inventor to develop a
heat-dissipation unit coated with oxidation-resistant nano thin
film and a method of depositing such oxidation-resistant nano thin
film on the heat-dissipation unit, in order to overcome the
drawbacks in the prior art.
SUMMARY OF THE INVENTION
[0011] A primary object of the present invention is to provide a
heat-dissipation unit coated with oxidation-resistant nano thin
film.
[0012] Another object of the present invention is to provide a
method of depositing an oxidation-resistant nano thin film on a
heat-dissipation unit.
[0013] To achieve the above and other objects, the heat-dissipation
unit coated with oxidation-resistant nano thin film according to
the present invention includes a metal main body having a
heat-absorbing portion and a heat-dissipating portion, and both of
the heat-absorbing portion and the heat-dissipating portion are
coated with at least a nano metal compound thin film. The
heat-dissipation unit can be a heat sink, a uniform temperature
plate, a radiating fin assembly, a heat pipe, a loop heat pipe, or
a water block. The nano metal compound thin film is formed via a
reaction of a reduction gas with at least a nano compound coating
and the metal main body. The metal main body can be made of copper,
aluminum, nickel or stainless steel.
[0014] To achieve the above and other objects, the method of
depositing an oxidation-resistant nano thin film on a
heat-dissipation unit according to the present invention includes
the steps of providing a heat-dissipation unit; forming at least a
nano compound coating on a surface of the heat-dissipation unit;
positioning the heat-dissipation unit in a high-temperature
environment; supplying a reduction gas into the high-temperature
environment to perform a heat treatment and a reduction process on
the heat-dissipation unit and the nano compound coating on the
surface of the heat-dissipation unit; and forming a nano metal
compound thin film on the surface of the heat-dissipation unit
after completion of the heat treatment and the reduction process.
The heat-dissipation unit can be a heat sink, a uniform temperature
plate, a radiating fin assembly, a heat pipe, a loop heat pipe, or
a water block. The reduction gas can be any one of H.sub.2S,
H.sub.2, CO, NH.sub.3, CH.sub.4, and any combination thereof, and
is preferably H.sub.2. The nano compound coating can be any oxide,
nitride, carbide, and sulfide, and is preferably an oxide. The
oxide is selected from the group consisting of SiO.sub.2,
TiO.sub.2, Al.sub.2O.sub.3, ZrO.sub.2, CaO, K.sub.2O, and ZnO. The
heat-dissipation unit is made of a material selected from the group
consisting of copper, aluminum, nickel, and stainless steel. The
nano compound coating is formed on the surface of the
heat-dissipation unit through a process selected from the group
consisting of physical vapor deposition (PVD), chemical vapor
deposition (CVD), and sol-gel deposition. Using the
oxidation-resistant nano thin film deposition method of the present
invention, at least a nano metal compound thin film can be formed
on the heat-dissipation unit to protect the latter against
formation of oxide on its surface and accordingly against
occurrence of increased thermal resistance thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The structure and the technical means adopted by the present
invention to achieve the above and other objects can be best
understood by referring to the following detailed description of
the preferred embodiments and the accompanying drawings,
wherein
[0016] FIG. 1a is a schematic view of a heat-dissipation unit
according to a first embodiment of the present invention;
[0017] FIG. 1b is a schematic view of a heat-dissipation unit
according to a second embodiment of the present invention;
[0018] FIG. 1c is a schematic view of a heat-dissipation unit
according to a third embodiment of the present invention;
[0019] FIG. 1d is a schematic view of a heat-dissipation unit
according to a fourth embodiment of the present invention;
[0020] FIG. 1e is a schematic view of a heat-dissipation unit
according to a fifth embodiment of the present invention;
[0021] FIG. 1f is a schematic view of a heat-dissipation unit
according to a sixth embodiment of the present invention;
[0022] FIG. 1g is an enlarged view of the circled area 1g of FIG.
1a;
[0023] FIG. 2a is a schematic view of a heat-dissipation unit
according to a seventh embodiment of the present invention;
[0024] FIG. 2b is a schematic view of a heat-dissipation unit
according to an eighth embodiment of the present invention;
[0025] FIG. 2c is an enlarged view of the circled area 2c of FIG.
2a;
[0026] FIG. 3 is a flowchart showing the steps included in a method
of depositing an oxidation-resistant nano thin film on a
heat-dissipation unit according to a first embodiment of the
present invention;
[0027] FIG. 4 schematically illustrates a reduction reaction
occurred on a heat-dissipation unit of the present invention and a
nano compound coating thereof;
[0028] FIG. 5 is a flowchart showing the steps included in a method
of depositing an oxidation-resistant nano thin film on a
heat-dissipation unit according to a second embodiment of the
present invention;
[0029] FIG. 6 schematically illustrates the forming of a nano
compound coating on a heat-dissipation unit of the present
invention;
[0030] FIG. 7 schematically illustrates a heat treatment and
reduction process performed on a heat-dissipation unit of the
present invention and a nano compound coating thereof; and
[0031] FIGS. 8 to 14 are X-ray photoelectron spectroscopy spectra
analyzing the surface of the heat-dissipation units according to
different embodiments of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0032] The present invention will now be described with some
preferred embodiments thereof and with reference to the
accompanying drawings. For the purpose of easy to understand,
elements that are the same in the preferred embodiments are denoted
by the same reference numerals.
[0033] Please refer to FIGS. 1a, 1b, 1c, 1d, 1e, 1f, 1g and 4. As
shown, a heat-dissipation unit 1 coated with oxidation-resistant
nano thin film according to any one of a first to a sixth
embodiment of the present invention includes a metal main body 11
having a heat-absorbing portion 111 and a heat-dissipating portion
112. The heat-absorbing portion 111 is arranged on one side of the
metal main body 11, and the heat-dissipating portion 112 is
arranged on an opposite side of the metal main body 11. The
heat-absorbing portion 111 and the heat-dissipating portion 112 are
externally coated with at least a nano metal compound thin film
2.
[0034] The metal main body 11 is formed of a material selected from
the group consisting of copper, aluminum, nickel, and stainless
steel.
[0035] In the first embodiment of the present invention, the
heat-dissipation unit 1 is a heat sink as shown in FIG. 1a. In the
second embodiment of the present invention, the heat-dissipation
unit 1 is a uniform temperature plate as shown in FIG. 1b. In the
third embodiment of the present invention, the heat-dissipation
unit 1 is a radiating fin assembly as shown in FIG. 1c. In the
fourth embodiment of the present invention, the heat-dissipation
unit 1 is a heat pipe as shown in FIG. 1d. In the fifth embodiment
of the present invention, the heat-dissipation unit 1 is a loop
heat pipe as shown in FIG. 1e. In the sixth embodiment of the
present invention, the heat-dissipation unit 1 is a water block as
shown in FIG. 1f.
[0036] The at least one nano metal compound thin film 2 is formed
by reaction of at least a reduction gas 5 with at least one nano
compound coating 6 and the metal main body 11. The at least one
nano compound coating 6 is coated on an outer surface of the metal
main body 11, and the reduction gas is supplied to the metal main
body 11 in a high-temperature environment, so that a diffusion
reaction and a reduction-oxidation reaction occur between the
reduction gas 5 and the nano compound coating 6 and the metal main
body 11. At completion of the reactions, the at least one nano
metal compound thin film 2 is formed on the metal main body 11.
[0037] Please refer to FIGS. 1b, 1d, 1e, 1f, 2a, 2b, 2c and 7. As
shown, the heat-dissipation unit 1 according to any one of the
second, the fourth, the fifth and the sixth embodiment of the
present invention includes a metal main body 11 defining a chamber
113 therein. The chamber 113 is provided on an interior surface
thereof with a wick structure 114, over which at least a nano metal
compound thin film 2 is coated, as can be most clearly seen in FIG.
2c.
[0038] The metal main body 11 is formed of a material selected from
the group consisting of copper, aluminum, nickel, and stainless
steel.
[0039] The wick structure 114 can be a grooved wick structure as
shown in FIG. 2a, a mesh wick structure as shown in FIG. 2b, a
copper sintered porous wick structure as shown FIG. 1d, or a
composite wick structure including any combination of the grooved,
mesh, and copper sintered porous wick structures (not shown).
[0040] The wick structure 114 is formed of a material selected from
the group consisting of copper, aluminum, nickel, and stainless
steel.
[0041] The heat-dissipation unit 1 can be any one of the uniform
temperature plate shown in FIG. 1b, the heat pipe shown in FIG. 1d,
the loop heat pipe shown in FIG. 1e, and the water block shown in
FIG. 1f.
[0042] The at least one nano metal compound thin film 2 is formed
by reaction of at least a reduction gas 5 with at least one nano
compound coating 6 and the aforesaid wick structure 114. The wick
structure 114 is coated with the at least one nano compound coating
6, and the metal main body 11 is subjected to a heat treatment in a
high-temperature environment while the reduction gas is supplied
into the metal main body 11, so that a diffusion reaction and a
reduction-oxidation reaction occur between the reduction gas 5 and
the nano compound coating 6 and the wick structure 114. At
completion of the reactions, the at least one nano metal compound
thin film 2 is formed on the wick structure 114.
[0043] In the above embodiments, the nano compound coating 6 can be
formed of any oxide, nitride, carbide or sulfide; and is preferably
formed of an oxide. The oxide is selected from the group consisting
of SiO.sub.2, TiO.sub.2, Al.sub.2O.sub.3, ZrO.sub.2, CaO, K.sub.2O,
and ZnO. And, the reduction gas 5 can be any one of H.sub.2S,
H.sub.2, CO, and NH.sub.3; and is preferably H.sub.2.
[0044] In the above embodiments, only one single layer or a
plurality of layers of the nano compound coating 6 can be formed.
In the case of forming a plurality of layers of the nano compound
coating 6, the oxide, nitride, carbide and sulfide can be
alternately coated.
[0045] FIG. 3 is a flowchart showing the steps included in a method
according to a first embodiment of the present invention for
depositing an oxidation-resistant nano thin film on a
heat-dissipation unit. Please refer to FIGS. 1a, 3 and 4 at the
same time. The method includes the following steps:
[0046] Step S1: Providing a heat-dissipation unit 1.
[0047] A heat-dissipation unit 1 is provided. The heat-dissipation
unit 1 can be a heat sink as shown in FIG. 1a, a uniform
temperature plate as shown in FIG. 1b, a radiating fin assembly as
shown in FIG. 1c, a heat pipe as shown in FIG. 1d, a loop heat pipe
as shown in FIG. 1e, or a water block as shown in FIG. 1f. The
method according to the first embodiment of the present invention
is explained based on a heat-dissipation unit 1 configured as a
heat sink.
[0048] Step S2: Forming at least a nano compound coating 6 on an
outer surface of the heat-dissipation unit 1 (i.e. the heat
sink).
[0049] At least a nano compound coating 6 is formed on an outer
surface of the heat-dissipation unit 1 (i.e. the heat sink). The
nano compound coating 6 can be formed of any oxide, nitride,
carbide or sulfide. The method according to the first embodiment of
the present invention is explained based on a nano compound coating
6 formed of an oxide. The oxide is selected from the group
consisting of SiO.sub.2, TiO.sub.2, Al.sub.2O.sub.3, ZrO.sub.2,
CaO, K.sub.2O, and ZnO. And, only one single layer or a plurality
of layers of the nano compound coating 6 can be formed. In the case
of forming a plurality of layers of the nano compound coating 6,
either different oxides are alternatively coated or the oxide,
nitride, carbide and sulfide are alternately coated.
[0050] The nano compound coating 6 can be formed through physical
vapor deposition (PVD), chemical vapor deposition (CVD), or sol-gel
process. The sol-gel process can be implemented in any one of the
following manners: dip-coating deposition, settle-coating
deposition, spin-coating deposition, brush-coating deposition, and
wet-coating deposition.
[0051] The method according to the first embodiment of the present
invention is explained based on at least one layer of the nano
compound coating 6 formed on the heat-dissipation unit 1 through
PVD. The deposited nano compound coating 6 has a thickness about 1
nm-100 nm. In the process of PVD, when the heat-dissipation unit 1
has a temperature about 150.degree. C., the target material is
zirconium (Zr) or titanium (Ti), and the vacuum degree of the
working environment is 10.sup.-3mbar, a nano compound coating 6
with high density and smoothness can be obtained.
[0052] Step S3: Supplying a reduction gas 5 into a high-temperature
environment to perform a heat treatment and a reduction process on
the heat-dissipation unit 1 and the nano compound coating 6 on the
surface of the heat-dissipation unit 1.
[0053] As shown in FIG. 4, the heat-dissipation unit 1 (i.e. the
heat sink) is positioned in a high-temperature environment, and the
reduction gas 5 is supplied into the high-temperature environment
to perform a heat treatment and reduction process on the nano
compound coating 6 on the heat-dissipation unit 1. The reduction
gas 5 can be any one of H.sub.2S, H.sub.2, CO, and NH.sub.3; and is
preferably H.sub.2. A reduction temperature for the reduction
process is ranged between 600.degree. C. and 1000.degree. C., and
is preferably ranged between 650.degree. C. and 850.degree. C.
[0054] Step S4: Forming a nano metal compound thin film 2 on the
heat-dissipation unit 1 after completion of the heat treatment and
reduction process.
[0055] After completion of the heat treatment and the reduction
process in the step S3, a diffusion reaction and a
reduction-oxidation reaction occur between the reduction gas 5
(i.e. H.sub.2) and the nano compound coating 6 and the
heat-dissipation unit 1. And, after completion of these reactions,
at least a nano metal compound thin film 2 is formed on the
heat-dissipation unit 1 (i.e. the heat sink).
[0056] FIG. 5 is a flowchart showing the steps included in a method
according to a second embodiment of the present invention for
depositing an oxidation-resistant nano thin film on a
heat-dissipation unit. Please refer to FIGS. 1d, 5, 6 and 7 at the
same time. The method includes the following steps:
[0057] Step S1: Providing a heat-dissipation unit 1 internally
provided with a wick structure 114.
[0058] A heat-dissipation 1 internally provided with a wick
structure 114 is provided. The heat-dissipation unit 1 can be a
uniform temperature plate as shown in FIG. 1b, a heat pipe as shown
in FIG. 1d, a loop heat pipe as shown in FIG. 1e, or a water block
as shown in FIG. 1f. The method according to the second embodiment
of the present invention is explained based on a heat-dissipation
unit 1 configured as a heat pipe shown in FIG. 1d.
[0059] Step S2: Forming at least a nano compound coating 6 over the
wick structure 114 in the heat-dissipation unit 1 through a sol-gel
process.
[0060] At least a nano compound coating 6 is formed on the wick
structure 114 in the heat-dissipation unit 1 (i.e. the heat pipe).
The nano compound coating 6 can be formed of any oxide, nitride,
carbide or sulfide. The method according to the second embodiment
of the present invention is explained based on a nano compound
coating 6 formed of an oxide. The oxide is selected from the group
consisting of SiO.sub.2, TiO.sub.2, Al.sub.2O.sub.3, ZrO.sub.2,
CaO, K.sub.2O, and ZnO. In the illustrated second embodiment, the
oxide is Al.sub.2O.sub.3. And, only one single layer or a plurality
of layers of the nano compound coating 6 can be formed. In the case
of forming a plurality of layers of the nano compound coating 6,
either different oxides are alternatively coated or the oxide,
nitride, carbide and sulfide are alternately coated. The nano
compound coating 6 can be formed through sol-gel process. The
sol-gel process can be implemented in any one of the following
manners: dip-coating deposition, settle-coating deposition,
spin-coating deposition, brush-coating deposition, and wet-coating
deposition.
[0061] In the illustrated second embodiment, while the oxide nano
thin film 6 is formed through dip-coating deposition, it is
understood the oxide nano thin film 6 can also be formed through
other types of deposition according to the sol-gel process. As
shown in FIG. 6, in the sol-gel process, Al.sub.2O.sub.3 particles
are soaked in a water solution 3, and the water solution 3 along
with the Al.sub.2O.sub.3 particles are poured into a tank 4 and
thoroughly mixed, so that the Al.sub.2O.sub.3 particles are evenly
dispersed in the water solution 3 contained in the tank 4. Then,
immerse the portion of the heat-dissipation unit 1 with the wick
structure 114 in the water solution 3 contained in the tank 4, and
allow the heat-dissipation unit 1 to remain still in the water
solution 3 in the tank 4 for a predetermined period of time.
Finally, remove the heat-dissipation unit 1 from the water solution
3 or drain off the water solution 3 from the tank 4, so that the
Al.sub.2O.sub.3 particles are attached to an outer surface of the
wick structure 114.
[0062] Step S3: Supplying a reduction gas 5 into a high-temperature
environment to perform a heat treatment and a reduction process on
the wick structure 114 of the heat-dissipation unit 1 and the nano
compound coating 6 on the surface of the wick structure 114.
[0063] The heat-dissipation unit 1 (i.e. the heat pipe) is
positioned in a high-temperature environment, and the reduction gas
5 is supplied into the high-temperature environment to perform a
heat treatment and a reduction process on the wick structure 114
and the nano compound coating 6. The reduction gas 5 can be any one
of H.sub.2S, H.sub.2, CO, and NH.sub.3; and is preferably H.sub.2.
A reduction temperature for the reduction process is ranged between
600.degree. C. and 1000.degree. C., and is preferably ranged
between 650.degree. C. and 850.degree. C.
[0064] Step S4: Forming a nano metal compound thin film 2 on the
wick structure 114 of the heat-dissipation unit 1 after completion
of the heat treatment and reduction process.
[0065] After completion of the reduction process in the step S3, a
diffusion reaction and a reduction-oxidation reaction occur between
the reduction gas 5 (i.e. H.sub.z) and the nano compound coating 6
and the wick structure 114. And, after completion of these
reactions, at least a nano metal compound thin film 2 is formed on
the wick structure 114 of the heat-dissipation unit 1.
[0066] In the methods according to different embodiments of the
present invention, the Al.sub.2O.sub.3 used is a nano-sol surface
pretreatment chemical (Product Number A-100) supplied by Chung-Hsin
Technological Consultants, Inc. (Taiwan). This nano-sol surface
pretreatment chemical mainly contains 1.0% of nanoparticles of
Al.sub.2O.sub.3 having a particle size 10 nm, and has the product
characteristics of a specific gravity of 1.01.+-.0.03; a flash
point higher than 100.degree. C.; a colorless and transparent
appearance; a pH value of 7.0.+-.0.5; and a working temperature of
10-40.degree. C.
[0067] After completion of the deposition of the
oxidation-resistant nano thin film on the heat-dissipation unit
using the methods according to different embodiments of the present
invention, the structure of the formed nano metal compound thin
films is analyzed via X-ray photoelectron spectroscopy (XPS)
technique. In formation about the equipment used in the XPS
analysis is as follows: [0068] Name of equipment supplier:
PerkinElmer (USA) [0069] Voltage: 15KV [0070] Watt: 300W [0071]
Vacuum degree: 2.5*10.sup.-9 torr
[0072] Following steps are included in the XPS analysis of the nano
metal compound thin films formed according to the present
invention:
[0073] Step 1: Performing a full scan on the nano metal compound
thin film with a spot size of 0.1 .ANG.;
[0074] Step 2: Etching downward to two different depths of 10 .ANG.
and 500 .ANG. below the surface of the nano metal compound thin
film, and performing a multiplex (local) scan with a spot size of
0.05 .ANG.; and
[0075] Step 3: Comparing the obtained XPS spectra with standard
spectra and performing a quantitative analysis.
[0076] Please refer to FIGS. 8 and 13 that are full-scan XPS
spectra of specimens with the formed nano metal compound thin
films. As can be seen from the spectra, there are copper, aluminum
and oxygen contained in the nano metal compound thin films.
[0077] FIGS. 9 and 12 are local-scan XPS spectra showing copper
binding energy values. The local scan is performed at etching
depths of 1 nm and 50 nm into the material. As can be seen from
FIG. 12, there is a layer of copper oxide less than 1 nm in
thickness formed on the surface of the material, while copper
exists 1 nm below the surface of the material.
[0078] FIGS. 10, 11 and 14 are local-scan XPS spectra showing
aluminum binding energy values. The local scan is performed at
etching depths of 1 nm and 50 nm into the material. As can be seen
from these figures, there is a layer of Al.sub.2O.sub.3 compound
(77.44eV) on the material surface. This layer of compound is a
chemical compound of Al.sub.2O.sub.3 and CuO, as shown in FIG. 11.
When the local scan is performed at an etching depth of 1 nm,
Al.sub.2O.sub.3 (74.86eV) appears; and when the local scan is
performed at an etching depth of 50 nm, Al.sub.2O.sub.3 still
appears, as shown in FIG. 14.
[0079] From the above analysis, it can be found the Al.sub.2O.sub.3
sol is a highly strong oxidant.
[0080] When the Al.sub.2O.sub.3 sol is coated on the surface of
copper, it will cause oxidation of the copper quickly, particularly
at a high temperature. When H.sub.2 is used in a high-temperature
environment to reduce the heat-dissipation unit coated with copper
oxide and aluminum oxide, the copper oxide on the surface of the
heat-dissipation unit is reduced and reacts with the aluminum oxide
to form a compound CuAl.sub.2O.sub.3, as shown in FIG. 8. This
layer of compound is able to stop oxidation of copper and forms an
oxidation-resistant nano thin film.
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