US20050082042A1

US20050082042A1 - Heat-dissipating structure and method of manufacturing the same

Info

Publication number: US20050082042A1
Application number: US10/919,961
Authority: US
Inventors: Robert Liang
Original assignee: Malico Inc
Current assignee: Malico Inc
Priority date: 2003-08-22
Filing date: 2004-08-17
Publication date: 2005-04-21
Also published as: TW200509776A

Abstract

A heat-dissipating structure and a manufacturing method thereof are provided The heat-dissipating structure includes a heat piece and a heat sink, wherein the heat piece includes an opening, a containing space, a wall surrounding the containing space, and a relatively high-volatility liquid is filled in the containing space. The manufacturing method includes steps of connecting the heat sink with the wall of the containing space for sealing the containing space by the heat sink, filling the containing space with the relatively high-volatility liquid through the opening, and closing the opening.

Description

FIELD OF THE INVENTION

The present invention is related to a heat-dissipating structure, and more particularly to a heat-dissipating structure made of a heat sink and a heat piece and a method of manufacturing the same.

BACKGROUND OF THE INVENTION

Since Jack Kilby who worked in Texas Instruments had invented the integrated circuit in 1959, the manufacturing process of semiconductor has been significantly improved in these few decades. In 1965, Mr. Moore who worked in Fairchild Semiconductor outlined the famous Moore's Law which influenced the semiconductor industry critically and the semiconductor technology indeed has progressed rapidly as his forecast therefrom. Therefore, the semiconductor manufacture technology has been developed from the minimum 0.7 mm line width and 100,000 pieces of transistors in 1989 to 0.13 mm line width and 5,000,000 pieces of transistors in 2000. In twenty-first century, the technology further has achieved the 0.1 mm line width and 10,000,000 pieces of transistors, and a Nano-century comes.
However, the diminution of electronic product influences the components and the systems correspondingly. The functions of chip are increased prominently but the area of chip is maintained the same or even less. It's become a huge challenge for the semiconductor engineers to adjust the capacity for more transistors and dissipate the increasing heat within the limited space. It is expectable, in the future, the functions of the chipset will be more powerful, the combined chipset will contain more and more chips, and the heat-dissipating problem will be a big barrier needed to be overcome.
Accordingly, the engineers try to solve this problem by designing various kinds of heat-dissipating devices. Generally, a heat-dissipating device includes fans and metals with high conduction coefficients, such as aluminum and copper. The heat-dissipating device is tightly stuck on the metal with high conduction coefficient, the thermal energy generated from the heat source is conducted to the end of the metal, and then the metal is cooled by the fans. This is a basic designed principle to maintain the running of the heat source under a fixed operation temperature by using the air convection. Such practicing process is identical with those of the radiator in a car, the heat-dissipating device in a household air conditioning, and the new and very large fan in an over-clocking desktop. However, the difference between the foregoing the heat-dissipating device of a computer and applications is that the heat-dissipating device in the computer must be designed for maintaining the convection and conduction in a small space thereof
Presently, a conventional heat-dissipating mode is that the heat generated from the heat sources of a CPU or a Video Graphics Array (VGA) in a computer is conducted to a heat sink or metals with high conduction coefficients through a packaging surface thereof and conducted to the heat-dissipating device, such as the fan and the heat sink, through the heat pipe to exhaust. However, this heat-dissipating mode is arrived by a thermal conduction between these devices and the entire thermal impedances thereof are increased and the cost is raised when the heat is exhausted through these devices. Moreover, mostly conventional heat sinks are made of aluminum alloys with middle conduction ability and maybe fail to cope with the present device having a increasingly heating power.
Furthermore, the reduced dimension and integrated function are the trends for the chip development. Thermal energy generated from chips is uniformly conducted to the whole heat piece by the heat pipe with high heat conductibility so as to reduce the instabilities of components come from of a local hotspot and to enhance the reliabilities and lifespans of the components.
The heat pipe is composed of a sealed receptacle, a capillary structure and a working fluid with a lower boiling point. The sealed receptacle is sealed after filling the working fluid with the lower boiling point into the vacuum cavity of the receptacle. And, the working fluid is at saturation state in the sealed receptacle. When one end of the receptacle is heated, the working fluid is vaporized accordingly and the vapor generated from the working fluid is condensed into coagulated liquids at another end of the receptacle. Moreover, the coagulated liquids are flowed to the heated end by capillarity or gravity, and a thermal exchange circulation is competed.
Because the thermal energy of the working fluid in the heat pipe is absorbed through a phase change between the liquid phase and the gas phase and is transmitted by a gas molecule, the heat conduction coefficient thereof is fifty times higher than aluminum and copper and the heat conductive effect is much better.
In practice, several kinds of heat sink structures and manufacturing processes thereof have been applied for the preceding heat pipe theory and describe as follows:
(1) A first heat-dissipating structure is formed by a heat sink 10 and a heat piece 11.
As shown in FIG. 1, which is a schematic view showing a first conventional heat-dissipating structure 1. The first heat-dissipating structure 1 is formed by the heat sink 10 and the heat piece 11, wherein the heat piece 11 includes the condenser 110 on a upper layer thereof and the evaporator 111 on a lower layer thereof. The manufacturing processes include creating a vacuum space between the condenser 110 and evaporator 111, filling the vacuum space with high-volatility liquids and sealing up the vacuum space. In the manufacturing process of the heat-dissipating structure, the heat sink 10 and the heat piece 11 are respectively manufactured and then they are welded. Such process has two shortcomings. Firstly, a housing thickness of the heat piece 11 is between 1˜3 mm, and an inflation is occurred in the heat piece 11 owing to the high temperature from welding, such that the inner structure thereof is broken and the heat-dissipating function is lowered or even lost. Secondly, the inflation will make a surface of the heat piece 11 uneven and leaky, and break the connection between the heat piece 11 and the heat sink 10, so that the heat-dissipating efficiency in the first heat-dissipating structure 1 will be affected accordingly.
(2) A second heat-dissipating structure is formed by a frame 22 combined with a heat sink 20 and a heat piece 21.
As shown in FIG. 2, which is a schematic view showing a second conventional heat-dissipating structure 2, in which the heat sink 20 and the heat piece 21 are fixed by using the frame 22. Moreover, the heat piece 21 includes a condenser 210 and an evaporator 211 and is similar to the heat piece 11 shown in FIG. 1. But two shortcomings are generated therefrom. Firstly, the heat sink 20 and the heat piece 21 merely are combined by the frame 22 through using screws or other fixing methods, and the combination of the heat sink 20 and the heat piece 21 is not closed enough, so that the heat-dissipating efficiency is poor. Secondly, a completed second heat-dissipating structure 2 is composed of the frame 22, the heat piece 21 and the heat sink 20 and has too many contact interfaces resulting in a too long heat-dissipating pathway, so that the heat-dissipating efficiency is affected.
(3) A third heat-dissipating structure is formed by a plurality of cooling fins 30 and a the heat piece 31 welded by the plurality of cooling fins 30.
As shown in FIG. 3, which is a schematic view showing a third conventional heat-dissipating structure. The third heat-dissipating structure 3 is different from the former heat-dissipating structures, and the plurality of cooling fins 30 are respectively welded on an upper condenser 310 of the heat piece 31 after the heat piece 31 is manufactured. The contact area, i.e. a extension portion 301 of each cooling fin 30, between the cooling fin 30 and the heat piece 31 in the third heat-dissipating structure 3 is less than that of the former prior arts. However, this prior art fails to avoid the defects of the former prior arts, wherein the heat piece 31 is manufactured first and then welded, so that an inflation and a poor connection are still occurred therein.
Additionally, a fourth heat-dissipating structure 4 shown in FIG. 4 is similar to the third heat-dissipating structure 3. The same function of the former heat piece is performed by using a copper tube 40 of the heat-dissipating structure 4. However, a basic problem of affecting the heat-dissipating efficiency still is not solved. Because a fixing method of cooling fins 41 respectively welded on the finished copper tube 40 filled with high-volatility liquids is identical to that of the third heat-dissipating structure 3, the fourth heat-dissipating structure 4 still has the inflation and the poor connection between the cooling fins 41 and the copper tube 40.
(4) A fifth heat-dissipating structure 5 is formed by a plurality of cooling fins 50 and a cooper pipe 51 covered thereby.
As shown in FIG. 5, which shows an improved study for improving the poor connection of the fourth heat-dissipating structure 4. The cooling fins 50 and the fifth heat-dissipating structure 5 are formed integrally and heated-up, so that the opening 52 has a thermal expansion and is able to contain the cooper pipe 51. Then the opening 52 is cooled down to be contracted for faying the cooper pipe 51. However, the filling process of the cooper pipe 51 is earlier than the faying or assembling process thereof, and the former shortcoming still is exist.
Therefore, a purpose of the present invention is to develop a structure to deal with the above situations encountered in the prior art.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a heat-dissipating structure and a method of manufacturing the same including a new manufacturing process for integrating a heat sink with a heat piece to avoid a welding process of integrating the heat piece with the heat sink. In addition, the connection between the heat sink and the heat piece, and the heat-dissipating efficiency are better in the present heat-dissipating structure.
According to an aspect of the present invention, a heat-dissipation structure including a heat piece and a heat sink is provided. The heat piece includes a containing space with a wall surrounding therearound and the heat sink is connected with the heat piece through the wall for sealing up the containing space.
Preferably, the heat piece is made of one of a metal having a high conduction coefficient and an alloy thereof
Preferably, the metal is copper (Cu).
Preferably, the metal is aluminum (Al).
Preferably, inner surfaces of the heat piece and the wall further include a metal powder layer disposed thereon.
Preferably, the metal powder is a copper (Cu) powder.
Preferably, the heat piece further includes a relatively high-volatility liquid filled in the containing space.
Preferably, the heat sink is made of one of a metal having a high conduction coefficient and an alloy thereof.
Preferably, the metal is copper (Cu).
Preferably, the metal is aluminum (Al).
According to another aspect of the present invention, a method of manufacturing a heat-dissipating structure is provided. The heat-dissipating structure includes a heat piece and a heat sink, the heat piece includes an opening and a containing space with a wall surrounding therearound, and the containing space is filled by a relatively high-volatility liquid. The method includes steps of (a) connecting the heat sink with the wall of the containing space for sealing the containing space by the heat sink, (b) filling the containing space with the relatively high-volatility liquid through the opening, and (c) closing the opening.
Preferably, the step (a) further includes a step of forming a metal powder layer in inner surface of the heat piece and the wall.
Preferably, the step (a) is performed by welding for connecting the heat sink with the wall of the containing space.
Preferably, the step (b) is performed through creating a vacuum so as to fill the containing space with the relatively high-volatility liquid.
The above contents and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed descriptions and accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view showing a first conventional heat-dissipating structure;
FIG. 2 is a schematic view showing a second conventional heat-dissipating structure;
FIG. 3 is a schematic view showing a third conventional heat-dissipating structure;
FIG. 4 is a schematic view showing a forth conventional heat-dissipating structure;
FIG. 5 is a schematic view showing a fifth conventional heat-dissipating structure;
FIG. 6 is a schematic view showing a heat-dissipating structure according to a preferred embodiment of the present invention; and
FIG. 7 is a cross-section view of the heat-dissipating structure in FIG. 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more specifically with reference to the following embodiment. It is to be noted that the following descriptions of preferred embodiment of this invention are presented herein for purpose of illustration and description only; it is not intended to be exhaustive or to be limited to the precise form disclosed.
Referring to FIG. 6, which is a schematic view showing a heat-dissipating structure according to a preferred embodiment of the present invention. The manufacturing process of the present heat-dissipating structure 6 includes spreading over a cooper powder layer 62 on the bottom surface of a containing space 611 of a trough-shaped heat piece 61 through sintering, closely welding the heat sink 60 at the wall 612 surrounding the containing space 611, filling a high-volatility liquid into the containing space 611 through the opening 613 of the wall 612 surrounding of containing space 611, and closing the opening 613.
The present heat-dissipating structure 6 is accomplished by welding the heat sink 60 to the wall 612 surrounding the heat containing space 611 of the heat piece 61 firstly and filling the high-volatility liquid into the heat containing space 611 lately, so that it decreases the manufacture cost of the heat piece 61 and shortens the heat-dissipating pathway. Further, the high-volatility liquid is filled into the heat piece 61 after the welding process, so that the present heat-dissipating structure 6 is able to eliminate the possible inflation damages happened to the inner structure of the heat piece 61 in the prior arts, and the connecting ability between the heat piece 61 and the heat sink 60 is improved.
Please FIG. 7, which is a cross view of the heat-dissipating structure in FIG. 6. After receiving the thermal energy generated from IC chips (not shown) and transformed via the trough-shaped heat piece 72 made of one of a metal having a high conduction coefficient, such as cooper, aluminum and so on, and an alloy thereof, and the high-volatility liquid 71 is evaporated to vapor and then raised close to the bottom of a heat sink 70. Further, the heat sink 70 is made of a material similar to that of the trough-shaped heat piece 72, so that the thermal energy of vapor will be absorbed by the heat sink 70 to exhaust out and the high-volatility liquid 71 is re-condensed due to an exothermic reaction. Moreover, a heat exchange circulation of the high-volatility liquid 71 is accomplished by a capillarity or a gravitational backflow in a cooper powder layer 73 surrounded on the inner wall of the trough-shaped heat piece 72.
Therefore, according to the above description, it is understood that the manufacturing technique for the present heat-dissipating structure can overcome the defects generated from the prior manufacturing processes. Further, the differences between the prior arts and the present invention and the advancements of the present invention, based on the heat-dissipating structure in FIG. 7, are respectively described as follow.
(1) Compared with the first conventional heat-dissipating structure 1 according to FIG. 1, the trough-shaped heat piece 72 is applied in the present heat-dissipating structure 7 and a base 701 of the heat sink 70 is serviced as a conducting interface rather than the condenser 110 on the heat piece 11 in FIG. 1. Therefore, the heat-dissipating pathway of the present heat-dissipating structure 7 has less conducting interfaces than that in FIG. 1 and has a better conduction efficiency. In addition, the present heat-dissipating structure 7 is accomplished by filling the high-volatility liquid 71 after welding the heat sink 70 to the heat piece 72, so that the inflation and the poor connection between the heat sink 70 and the heat piece 72 would be avoided and a better heat-dissipating efficiency is generated therefrom.
(2) Compared with the second conventional heat-dissipating structure 2 according to FIG. 2, similar to the first conventional heat-dissipating structure 1 of FIG. 1, the trough-shaped heat piece 72 is applied in the present heat-dissipating structure 7 and the base 701 of the heat sink 70 is serviced as a conducting interface rather than the condenser 210 on the heat piece 22 in FIG. 2. In addition, the present heat-dissipating structure 7 is accomplished by filling the high-volatility liquid 71 after welding the heat sink 70 to the heat piece 72, so that the inflation and poor connection between the heat sink 70 and the heat piece 72 would be avoided. Further, the frame 22 of FIG. 2 is not available to the resent heat-dissipating structure 7, so that yield ratio of the connection is increased and the relevant cost is decreased.
(b 3) Compared with the third conventional heat-dissipating structure 3 according to FIG. 3, the present invention still has the advantage described above. Although the contact area in FIG. 3, i.e. extension portion 301, between the plurality of cooling fins 30 and the heat piece 30 is smaller than the contact areas, i.e. the condensers 110, 210, in the first and second conventional heat-dissipating structures 1, 2, it still has the problems of the inflation and the poor connection. In addition, since the third conventional heat-dissipating structure 3 still includes an extra conducting interface compared with the present heat-dissipating structure 7, it includes a poor heat-dissipating efficiency. Besides, the manufacturing process for the third conventional heat-dissipating structure 3 is identical to the those of the above two prior arts, wherein the step of welding the cooling fins 31 is after the step of fabricating the heat piece 31. However, the present heat-dissipating structure 7 is accomplished by filling the high-volatility liquid 71 after welding the heat sink 70 to the heat piece 72, so that the inflation and poor connection between the heat sink 70 and the heat piece 72 would be avoided. Otherwise, the same results could be used as the comparison between the conventional heat-dissipating structures 4, 5 shown in FIG. 4 and FIG. 5 and the present heat-dissipating structure 7 in FIG. 7.
In conclusion, it is understood that the present heat-dissipating structure could enhance the connection between the heat sink and the heat piece. Further, an excellent heat-dissipating efficiency is achieved by modifying the conventional manufacturing process and providing a new heat-dissipating assembly according to the present invention.
While the invention has been described in terms of what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention need not to be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.

Claims

1. A heat-dissipating structure comprising:

a heat piece comprising a containing space with a wall surrounding therearound; and

a heat sink connected with said heat piece through said wall for sealing up said containing space.

2. The heat-dissipating structure according to claim 1 wherein said heat piece is made of one of a metal having a high conduction coefficient and an alloy thereof.

3. The heat-dissipating structure according to claim 2 wherein said metal is copper (Cu).

4. The heat-dissipating structure according to claim 2 wherein said metal is aluminum (Al).

5. The heat-dissipating structure according to claim 1 wherein inner surfaces of said heat piece and said wall further comprise a metal powder layer disposed thereon.

6. The heat-dissipating structure according to claim 5 wherein said metal powder is a copper (Cu) powder.

7. The heat-dissipating structure according to claim 1 wherein said heat piece further comprises a relatively high-volatility liquid filled in said containing space.

8. The heat-dissipating structure according to claim 1 wherein said heat sink is made of one of a metal having a high conduction coefficient and an alloy thereof.

9. The heat-dissipating structure according to claim 8 wherein said metal is copper (Cu).

10. The heat-dissipating structure according to claim 8 wherein said metal is aluminum (Al).

11. A method of manufacturing a heat-dissipating structure, wherein said heat-dissipating structure comprises a heat piece and a heat sink, said heat piece comprises an opening and a containing space with a wall surrounding therearound and said containing space is filled by a relatively high-volatility liquid, said method comprising steps of:

(a) connecting said heat sink with said wall of said containing space for sealing said containing space by said heat sink;

(b) filling said containing space with said relatively high-volatility liquid through said opening; and

(c) closing said opening.

12. The method according to claim 11 wherein said step (a) further comprises a step of: forming a metal powder layer on inner surfaces of said heat piece and said wall.

13. The method according to claim 11 wherein said step (a) is performed by welding for connecting said heat sink with said wall of said containing space.

14. The method according to claim 11 wherein said step (b) is performed through creating a vacuum so as to fill said containing space with said relatively high-volatility liquid.