TWI395918B - Vapor chamber and manufacturing method thereof - Google Patents

Description

Temperature equalizing plate and manufacturing method thereof

The present invention is related to a heat conducting device and, in particular, to a temperature equalizing plate that can be used to dissipate heat from an electronic system.

A vapor chamber is a type of heat pipe that is widely used to cool high-power semiconductor wafers, such as a central processing unit and a graphics processor in an electronic system, because of its excellent heat transfer characteristics. Or a high power light emitting diode. By quickly transferring the heat generated by the operation of the semiconductor wafer away from its working environment, it is ensured that the electronic system operates efficiently under normal conditions.

The outer casing material of the temperature equalizing plate is usually a metal such as copper, aluminum or stainless steel, and the inner space is filled with a working fluid whose chemical property is compatible with the metal. Figure 1 is a schematic diagram of a typical isothermal plate. As shown in FIG. 1, a heat source 20, such as a high power electronic wafer, is in contact with the lower surface 12 of the temperature equalization plate 10. The heat generated by the heat source 20 is conducted to the temperature equalizing plate 10. The region of the temperature equalization plate 10 in contact with the heat source 20 can be regarded as a heating zone in which the working fluid is thereby evaporated to a vapor state and diffused to the interior of the entire temperature equalization plate.

When the vaporous working fluid contacts the cooling zone with a relatively low temperature in the half of the temperature equalizing plate, it releases the latent heat and is recondensed into a liquid working fluid, and drops directly down due to its own gravity, or The support structure is moved back to the lower half along the support structure between the upper and lower halves of the temperature equalization plate 10, or flows back along the capillary structure 16 to the lower half. The latent heat will be dissipated into the surrounding air via the upper surface 14 of the temperature equalization plate 10.

By the capillary force provided by the capillary structure 16 (the area marked with a shadow in Figure 1), the liquid working fluid returning to the lower half of the temperature equalizing plate 10 is directed to the heating zone to complete a cycle. By using the heat transfer between the working fluid and the two-phase change of the vapor, the temperature equalizing plate 10 can achieve the heat dissipation effect of the heat source 20.

The capillary structure of the conventional uniform temperature plate is mostly a powdery porous type, a mesh type, a groove type, or a composite capillary structure in which the above three patterns are combined. The cost of the grooved capillary structure is lower, but its heat flux is only 30 watts per square centimeter, which is not suitable as a heating zone capillary structure for the uniform temperature plate of high power semiconductor crystal applications.

The mesh-like capillary structure and the upper plate or the lower plate of the temperature equalizing plate are in contact with each other to control the heat transfer performance of the uniform temperature plate; if the fitting state is not good, the thermal resistance of the temperature equalizing plate is greatly increased. . Conventional techniques often increase the adhesion between the web material and the sheet by means of high temperature sintering. However, the cost required for the high-temperature sintering process is high and the production takes a long time and the energy consumption is large, so that the manufacturing cost of the uniform temperature plate is high.

In addition, the operating temperature required for the high temperature sintering process far exceeds the annealing temperature of the material of the temperature equalizing plate. For example, the annealing temperature of copper is generally 450 degrees Celsius, and the temperature of the sintering process is higher than 850 degrees Celsius. The mechanical strength of the uniform temperature plate casing tends to be greatly reduced. Even in the process of vacuuming and degassing after filling the working fluid, the concave phenomenon of the plate may occur, which in turn causes the contact thermal resistance between the temperature equalizing plate and the heat source to rise. .

Powder porous wicking structures are also typically used to bond metal powder or ceramic powder to a plate of a uniform temperature plate using a high temperature sintering process. This capillary structure also has the problem that the sintering process destroys the mechanical strength of the uniform temperature plate outer casing and the contact thermal resistance increases.

In order to improve the mechanical strength of the temperature equalization plate and reduce the production cost thereof, the present invention proposes the concept of producing a capillary structure of a uniform temperature plate by a cold plasma spray coating technique.

A method of making a temperature equalization plate in accordance with an embodiment of the present invention. The method first provides an upper cover and a lower cover. A capillary structure is then formed in the lower cover by a cold spray spray process. Then, the upper cover and the lower cover are assembled to define at least one accommodating space, and the capillary structure is located in the accommodating space. Finally, after the working space is filled in the accommodating space, the accommodating space is sealed.

Another embodiment of the invention is a temperature equalization plate comprising a housing, a working fluid and a capillary structure. The interior of the housing has at least one receiving space. The workflow system is filled in and filled in the accommodating space. The capillary structure is formed on the inner wall of the accommodating space via a cold spray coating process.

The advantages and spirit of the present invention will be further understood from the following detailed description of the invention.

Referring to FIG. 2, FIG. 2 is a flow chart of a method for fabricating a temperature equalizing plate according to an embodiment of the present invention. The method first performs step S21 to provide an upper cover and a lower cover. For example, the manufacturer can use a metal plate such as copper, aluminum, stainless steel or the like as a material to manufacture the upper cover plate 32 as shown in FIG. 3(A) by forging, extrusion or casting. According to a preferred embodiment, the upper cover 32 is formed by cold forging, but is not limited thereto. In addition, a plurality of columnar structures below the upper cover 32 can be used as the support structure 32A separating the upper cover 32 and the lower cover 34.

Figure 3 (B) shows another example of the upper undercover according to the present invention. The more irregularly shaped support structure 32A in this example can be implemented by chemical etching of the upper cover 32. The manufacturer can also use the thin metal plate as the material to manufacture the lower cover 34 as shown in FIG. 3(A) and FIG. 3(B) by cold forging and stamping, but not limited thereto.

Next, step S22 forms a capillary structure on the lower cover by a cold spray spraying process. Figure 4 is a schematic view of the cold spray spray process, i.e., an example of the implementation of step S22, and the device of reference numeral 40 represents a cold spray gun. In this example, the cold melt gun 40 has a feed point 42 at each of its upper and lower ends, from which the spray material is fed into the front end of the cold spray gun 40. In practice, the spray material fed to the feed site 42 may be a rod or wire of metal or ceramic material, or may be powdered material particles.

The cold spray spray process may first form an arc region 46 with the high voltage electrode 44, thereby dissociating a first working gas (such as an inert gas such as argon) passing through one of the arc regions 46 to form a temperature of approximately Plasma from 2000 to 3000 degrees Celsius. After the spray material is fed from the feed point 42 to the front end of the cold spray gun 40, it is melted by the high temperature of the plasma to form a molten material liquid.

In the process of producing the molten material liquid, a second working gas (e.g., high pressure nitrogen gas and/or hydrogen gas) is continuously blown toward the front end in the A direction shown in Fig. 4 by the air inlet port at the rear end of the cold spray gun 40. The molten material liquid is blown by the second working gas and will be blown off into a plurality of spray particles 48 flying down the cover plate 34. In practice, these sprayed particles 48 have an average diameter of between about 35 microns and 250 microns.

According to the invention, the spray coating material can be completely melted by the plasma. By appropriately selecting the distance between the cold spray gun 40 and the lower cover 34, the sprayed particles 48 can be cooled for a sufficient time during flight and solidified before being blown to the lower cover 34. These sprayed particles 48 adhere to the surface of the lower cover 34 due to a mechanical impact force after being impacted at a high speed on the lower cover 34, and are stacked to form a porous structure 36 having a thickness of about 0.1 cm to 0.8 cm as shown in FIG. Figure 5 is a schematic view of the capillary structure and the lower cover according to the present invention. This porous structure 36 can be used as the capillary structure of the lower cover 34.

In practice, the first working gas may be included in the second working gas blown into the cold spray gun 40 by the air inlet of the rear end. In other words, the second working gas may comprise nitrogen, hydrogen, argon or a mixture of these gases. The addition of nitrogen to the second working gas prevents the sprayed particles 48 from being oxidized by reacting with the surrounding oxygen during flight, and the hydrogen can reduce the oxide layer on the surface of the sprayed particles 48.

For example, in the case where the material of the spray coating material is copper and the material of the lower cover 34 is aluminum, when the copper particles are sprayed on the aluminum substrate in the cold spray spray process, the temperature of the aluminum substrate is only the chamber. The temperature rises to 40 degrees Celsius, which is much lower than the annealing temperature of the aluminum substrate. Therefore, the mechanical strength of the lower cover 34 according to the present invention is not impaired by the procedure for fabricating the capillary structure.

In practical applications, in addition to the lower cover 34, the manufacturer can also spray the sprayed material onto the top plate 32 of the temperature equalization plate by means of cold spray coating technology, and a capillary structure is also formed on the inner side of the upper cover 32. In addition, the manufacturer may also use a cold melt spray technique to form a capillary structure on the surface of the support structure 32A.

Next, step S23 is to assemble the upper cover 32 and the lower cover 34 to define at least one accommodating space 38. Please refer to FIG. 6. FIG. 6 is a schematic view of the upper cover and the lower cover assembled according to the present invention. In the example of FIG. 6, the capillary structure 36 is distributed over the lower cover 34. As shown in FIG. 6, after the upper cover 32 and the lower cover 34 are assembled, the support structure 32A is abutted between the upper cover 32 and the lower cover 34, and a plurality of accommodation spaces 38 are defined.

In practice, the creator can assemble the upper cover 32 and the lower cover 34 using a laser welding procedure or a plasma arc welding procedure. Welding methods such as plasma arc welding and laser welding have small heat-affected areas during welding. Through the proper temperature equalization plate design, this welding procedure does not destroy the structural strength of the heat transfer and heat dissipation areas of the temperature equalization plate.

Step S24 is to fill a working space in the accommodating space 38. In practice, the manufacturer can weld a fill tube between the two covers by welding the upper cover 32 and the lower cover 34 while tungsten inert gas (TIG) welding (not present) In the drawing), the working fluid is filled through the filling tube.

After the sealing of the accommodating space 38 is performed in step S25, the manufacturing process of the temperature equalizing plate is completed according to the manufacturing method of the present invention. In a practical application, before sealing the accommodating space 38 and the filling tube, the manufacturer may first remove the non-condensable gas from the accommodating space 38 to make the temperature equalizing plate work.

Please refer to FIG. 7. FIG. 7 is a flow chart of a method for fabricating a temperature equalizing plate according to another embodiment of the present invention. In addition to steps S21 to S25, the manufacturing method further includes step S26 and step S27 after step S21. Step S26 performs a surface roughening procedure such as sand blasting on the upper cover 32, the lower cover 34, or a combination thereof to reinforce the adhesion between the subsequent capillary structure 36 and the upper cover 32 and the lower cover 34. In step S27, the upper cover 32 and the lower cover 34 are cleaned by an ultrasonic cleaning program to remove dust or impurities thereon.

According to another embodiment of the present invention, a temperature equalizing plate fabricated by the manufacturing method of FIG. 2 is used. The temperature equalization plate comprises a casing, a working fluid and a capillary structure. The interior of the housing has at least one receiving space. The workflow system is filled in and filled in the accommodating space. The capillary structure is formed on the inner wall of the accommodating space via a cold spray coating process.

As previously described, in addition to the housing, the working fluid, the capillary structure, the temperature equalization plate according to the present invention may further comprise at least one support structure for separating the upper and lower cover plates of the temperature equalization plate. In addition, the capillary structure may be distributed only on the lower cover of the casing of the temperature equalization plate, or may be distributed on the upper cover and the lower cover of the casing at the same time.

The present invention proposes the concept of making a capillary structure of a uniform temperature plate by a cold melt spray coating technique. Since the cold spray coating technique does not greatly increase the temperature of the sprayed substrate, the temperature of the temperature equalization plate does not exceed the annealing temperature during the process of fabricating the capillary structure; thereby, the average temperature of the present invention can be maintained. The mechanical strength of the board, while ensuring the contact resistance of the temperature equalizing plate, does not increase significantly due to the procedure for making the capillary structure.

In addition, the cost required for the high-temperature sintering process employed in the prior art is high and the production takes a long time and the energy consumption is large. The invention proposes that the method of manufacturing the capillary structure of the uniform temperature plate by the cold melt spraying technology can effectively shorten the production man-hour of the uniform temperature plate, improve the production efficiency and reduce the cost, and improve the competitiveness of the product.

The features and spirit of the present invention will be more apparent from the detailed description of the preferred embodiments. On the contrary, the intention is to cover various modifications and equivalents within the scope of the invention as claimed.

10. . . Temperature plate

12. . . lower surface

14. . . Upper surface

16. . . Capillary structure

20. . . Heat source

S21~S25. . . Process step

32. . . Upper cover

34. . . Lower cover

32A. . . supporting structure

36. . . Capillary structure

38. . . Housing space

40. . . Cold spray gun

42. . . Feeding place

44. . . High voltage electrode

46. . . Arc zone

48. . . Sprayed particles

S26~S27. . . Process step

Figure 1 is a schematic diagram of a typical isothermal plate.

2 is a flow chart of a method for fabricating a temperature equalization plate in accordance with an embodiment of the present invention.

Figure 3 (A) and Figure 3 (B) are examples of the upper and lower covers of the temperature equalization plate.

Figure 4 is a schematic diagram of the cold spray spray process.

Figure 5 is a schematic view of the capillary structure and the lower cover according to the present invention.

Figure 6 is a schematic view of the upper cover and the lower cover assembled according to the present invention.

Figure 7 is a flow chart of a method for fabricating a temperature equalizing plate in accordance with another embodiment of the present invention.

S21~S25. . . Process step

Claims (25)

A method of making a temperature equalizing plate comprising the steps of: (a) providing an upper cover and a lower cover; (b) forming a capillary structure on the lower cover by a cold spray spraying process, the cold melting The spray coating process comprises: forming an arc zone by a high voltage electrode; dissociating a first working gas passing through one of the arc zones to form a plasma having a temperature system between 2000 ° C and 3000 ° C; providing a spray Coating material; melting the spray material by the plasma to form a molten material liquid; blowing the molten material liquid with a second working gas, thereby generating a plurality of sprayed particles and spraying the sprayed particles Blowing toward the lower cover, the sprayed particles are solidified before being blown to the lower cover; and forming the capillary structure stacked on the lower cover and being porous; (c) assembling the upper cover and The lower cover defines at least one accommodating space, the capillary structure is located in the accommodating space; (d) filling the accommodating space with a working fluid; and (e) sealing the accommodating space. The method for producing a temperature equalizing plate according to claim 1, wherein the step (a) and the step (c) further comprise the step of: forming the capillary structure on the cold melt spraying process; Cover plate. The method for producing a temperature equalizing plate according to claim 1, wherein the step (a) further comprises the step of forming at least one supporting structure on the upper cover by a chemical etching process. The method for producing a temperature equalizing plate according to claim 3, wherein after the upper cover and the lower cover are assembled in the step (c), the supporting structure is abutted against the upper cover and the lower Between the cover plates, assist in defining a plurality of such accommodation spaces. The method for producing a temperature equalizing plate according to claim 3, further comprising the step of: forming the capillary structure on the support by the cold melt spraying process between the step (a) and the step (c) The surface of the structure. A method of producing a temperature equalizing plate as described in claim 1, wherein the step (a) comprises making the lower cover by a cold forging stamping process. A method of producing a temperature equalizing plate as described in claim 1, wherein the step (a) comprises performing a surface roughening procedure for the upper cover, the lower cover or a combination thereof. The method for producing a temperature equalizing plate according to claim 1, wherein the step (a) and the step (b) further comprise the following steps: cleaning the upper cover and the lower cover by an ultrasonic cleaning program. board. A method of fabricating a temperature equalizing plate as described in claim 1, wherein the step (c) is to assemble the upper cover and the lower cover by a laser welding procedure or a plasma arc welding procedure. The method for producing a temperature equalizing plate according to claim 1, wherein the spraying material is a linear material before the step of melting the spray material by the plasma to form the molten material liquid or A rod of material. A method for producing a temperature equalizing plate as described in claim 1 of the patent application, wherein The spray coating material is a metal material or a ceramic material. A method of producing a temperature equalizing plate as described in claim 1, wherein the first working gas comprises an argon gas. A method of producing a temperature equalizing plate as described in claim 1, wherein the second working gas comprises a hydrogen gas or a nitrogen gas. The method for producing a temperature equalizing plate according to claim 1, wherein in the step of melting the spray material by the plasma to form the molten material liquid, the spray material is subjected to the plasma Completely melted. A method of producing a temperature equalizing plate as described in claim 1, wherein one of the sprayed particles has an average diameter of between 35 micrometers and 250 micrometers. The method of producing a temperature equalizing plate according to claim 1, wherein the lower cover has an annealing temperature, and the lower cover has an operating temperature in the cold spray spraying process, the working temperature Below the annealing temperature. The method for producing a temperature equalizing plate according to claim 1, wherein the step (c) and the step (d) further comprise the step of: pumping out a non-condensable gas in the accommodating space. A temperature equalizing plate comprising: a casing having at least one accommodating space therein; a working fluid filled in the accommodating space; and a capillary structure formed in the accommodating space via a cold spray spraying process An inner wall; wherein the cold spray spray process comprises: Forming an arc zone by a high voltage electrode; dissociating a first working gas passing through one of the arc zones to form a plasma having a temperature system between 2000 ° C and 3000 ° C; providing a spray coating material; And pulverizing the spray material to form a molten material liquid; blowing the molten material liquid with a second working gas, thereby generating a plurality of sprayed particles and blowing the sprayed particles toward the accommodating space The inner wall, the sprayed particles are solidified before being blown to the inner wall; and the capillary structure is formed on the inner wall and is porous. The temperature equalizing plate according to claim 18, wherein the housing comprises an upper cover and a lower cover, and the upper cover is assembled on the lower cover to define the receiving space. The temperature equalizing plate according to claim 19, further comprising: a supporting structure, the supporting structure is abutted between the upper cover and the lower cover for separating the inside of the housing into plural This accommodation space. The temperature equalizing plate according to claim 19, wherein the capillary structure is distributed in the lower cover. The temperature equalizing plate according to claim 19, wherein the capillary structure is simultaneously distributed on the upper cover and the lower cover. The temperature equalizing plate according to claim 18, wherein the casing is made of a metal material. The temperature equalizing plate according to claim 18, wherein the capillary structure is chemically compatible with the working fluid. The temperature equalizing plate according to claim 18, wherein the capillary structure is formed by a cold melt spraying process using a metal material or a ceramic material.