Three-dimensional heat sink and manufacturing method thereof

Abstract

The present invention discloses a three-dimensional heat spreader and a manufacturing method thereof, the manufacturing method comprising: providing a shell with a closed shell structure, a reflux cavity is provided in the inner cavity of the shell, and a through hole is provided on the cavity wall of the reflux cavity; a liquid absorbent core is manufactured by slurry manufacturing, coating, high temperature treatment, cutting and shaping processing steps, the porosity of the liquid absorbent core is 40% to 90%, the holes in the liquid absorbent core are through holes with a micro-nano aperture, and the through holes are connected to form a channel for rapid flow of a liquid phase medium; after the liquid absorbent core is placed in a preset position in the inner cavity of the shell, it is sintered and combined into one body to obtain a three-dimensional heat spreader in which the channel is connected and communicated with the reflux cavity. The manufacturing method is simple and reasonable, and can realize continuous and large-scale production. The obtained three-dimensional heat spreader has high three-dimensional heat conduction efficiency, miniaturized structure, high finished product yield, good reliability, and long service life, and has important practical value and broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of vapor chambers, and in particular to a three-dimensional vapor chamber and a manufacturing method thereof. Background Art

[0002] As a new type of two-phase heat dissipation technology, the vapor chamber has the advantages of high thermal conductivity, good temperature uniformity, and reversible heat flow direction. It overcomes the problems of small contact area, large thermal resistance, and uneven heat flux density of traditional heat pipes, and has become one of the effective ways to solve the heat dissipation of high heat flux density electronic devices in the future electronics industry. Compared with traditional heat pipes, which are considered to have a one-dimensional heat conduction effect, the vapor chamber is generally considered to have a two-dimensional heat conduction effect.

[0003] The three-dimensional heat spreader is the development of the conventional heat spreader. It is based on the existing heat spreader to make the medium phase change flow field achieve a three-dimensional heat conduction effect. The three-dimensional heat spreader mainly includes a shell, a medium and a wick. The wick has a unique three-dimensional structure and capillary microchannels, which can enable the medium flowing through the wick to achieve efficient phase change heat transfer, thereby improving the heat conduction capacity. Currently, the three-dimensional heat spreader has been applied to high-end laptops, AI computing power, data center servers, workstations and other fields, effectively solving the heat conduction problem of the above-mentioned electronic devices / equipment.

[0004] However, with the continuous increase in the power heat flux density of electronic devices / equipment, the existing three-dimensional heat spreader structure faces the following technical difficulties: 1) In order to ensure the efficient circulation of the two-phase medium in the three-dimensional heat spreader, the design and processing of the liquid absorbent core are required to be very precise, that is, the liquid absorbent core needs to have a large number of capillary microchannels, and the capillary microchannels must be connected and continuous to ensure that the medium can quickly flow back to the heat source end after the gas state is converted into a liquid state, so as to achieve efficient circulation. However, since the existing liquid absorbent core usually adopts a sintered structure of copper powder or a sintered structure of a woven copper mesh, and the process and processing of the three-dimensional structure of the above sintered structure are very difficult, it is difficult to achieve the continuity of the overall capillary microchannel, resulting in the thermal conductivity of the three-dimensional heat spreader failing to meet the requirements and the finished product yield being low. 2) Similarly, since the existing liquid absorbent core adopts a sintered structure of copper powder or a sintered structure of a woven copper mesh, this will also cause the porosity of the liquid absorbent core to be low, and the porosity of the liquid absorbent core will be directly related to the amount of medium added, which will further cause the thermal conductivity of the three-dimensional heat spreader to fail to meet the design requirements. 3) The existing manufacturing process of the three-dimensional heat spreader is relatively complex and the processing cost is high, and it is urgent to develop a more economical and efficient large-scale production method. 4) The three-dimensional heat spreader needs to be closely integrated with the overall system of the electronic device, which requires the optimization of its overall thermal design to achieve efficient thermal coupling and heat diffusion.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] In order to overcome the above-mentioned defects, the present invention provides a three-dimensional heat spreader and a method for manufacturing the same. The manufacturing method is simple, reasonable, and novel, and can realize continuous and large-scale production. The obtained three-dimensional heat spreader has high three-dimensional heat conduction efficiency, miniaturized structure, high finished product yield, good reliability, and long service life, which well meets the actual application needs, has important practical value and broad application prospects.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a method for manufacturing a three-dimensional heat sink, comprising the following manufacturing steps:

[0008] S1: providing a shell, wherein the shell is a closed shell structure formed by combining at least two parts, wherein a reflux cavity capable of contacting an external heat source end is provided in an inner cavity of the shell, and a through hole with a quantitative or adjustable porosity and a micro-nano-scale pore size is provided on a cavity wall of the reflux cavity;

[0009] S2: Making a liquid absorbent core: by weight percentage, 45% to 60% of fine powder, 15% to 30% of solvent, 5% to 15% of binder, 1% to 3% of foaming agent and 10% to 20% of pore-forming agent are mixed evenly to obtain a slurry; wherein the fine powder is made of a material having thermal conductivity and not reacting with the medium through an atomization powder making process; the obtained slurry is evenly coated on a carrier to form a wet film, and the wet film is subjected to high temperature treatment to obtain a large liquid absorbent core plate with a porous network structure; then the obtained liquid absorbent core plate is cut and shaped to obtain the liquid absorbent core; and the porosity of the liquid absorbent core is 40% to 90%, and the pores in the liquid absorbent core are through holes with a pore size of micro-nanoscale, and the through holes are also connected to form a channel for rapid flow of the liquid phase medium;

[0010] S3: placing the liquid absorbent core at a preset position in the inner cavity of the shell, and then combining them into one by sintering, so as to obtain a three-dimensional heat spreader in which the channel is fixedly connected and communicated with the reflux cavity.

[0011] As a further improvement of the present invention, in the above S2, the fine powder material is copper powder with a particle size of 1 to 150 μm;

[0012] The solvent comprises deionized water and an organic solvent, wherein the organic solvent is selected from at least one of methanol, ethanol, propanol, isopropanol, acetone, toluene, xylene, terpineol, triethanolamine, dimethylformamide, isophorone and dibasic acid esters;

[0013] The binder is selected from at least one of dextrin, α-starch, polyurethane, nitrocellulose, polyvinyl acetate, polyacrylate, phenolic resin, polyvinyl acetate resin and urea-formaldehyde resin;

[0014] The foaming agent is selected from at least one of ammonium bicarbonate and UNICELL-MS series expansion agents;

[0015] The pore former is selected from at least one of polyethylene, polypropylene, polyvinyl chloride and polystyrene.

[0016] As a further improvement of the present invention, in the above S2, the material of the carrier is glass or ceramic;

[0017] The wet film is subjected to high temperature treatment by a high temperature sintering process, and the specific processing conditions of the high temperature sintering process are: nitrogen is used as the protective gas, and a hydrogen-nitrogen mixed gas produced by the decomposition of ammonia is used as the reducing gas; and sintering is performed at 750-950° C. for 30-120 minutes.

[0018] As a further improvement of the present invention, in the above S2, the large plate of the liquid absorbent core is a sheet structure with a thickness of 0.05 to 5 mm; the shape of the liquid absorbent core is conformed to the shape of the inner cavity of the shell.

[0019] As a further improvement of the present invention, the microstructures of the absorbent core plate and the absorbent core are both hierarchical structures, and the holes in the absorbent core plate and the absorbent core are three-dimensional through holes with an average pore size of 2 to 500 μm.

[0020] As a further improvement of the present invention, in the above S3, the specific processing conditions of the sintering process are: nitrogen is selected as the protective gas, and the hydrogen-nitrogen mixed gas produced by the decomposition of ammonia is selected as the reducing gas; and sintering is performed at 750-850°C for 30-90min.

[0021] As a further improvement of the present invention, in the above S3, after the absorbent core is placed at a preset position in the inner cavity of the shell, a support column for supporting and limiting the absorbent core is further provided in the inner cavity of the shell, and then the support columns are sintered and combined into one.

[0022] As a further improvement of the present invention, the support column also adopts a porous network structure, and the porosity of the support column is 40% to 90%, and the pores in the support column are three-dimensional through holes with an average pore size of 2 to 500 μm.

[0023] The present invention also provides a three-dimensional heat spreader, which is manufactured using the manufacturing method of the three-dimensional heat spreader described in the present invention.

[0024] As a further improvement of the present invention, the absorbent core includes a first part and two second parts respectively connected to the two ends of the first part, the through holes on the first part and the two second parts are connected to form the channel, and the two second parts are also respectively connected to the opposite sides of the reflux cavity, so that the channel is connected to the reflux cavity; in addition, the thickness of the first part and the two second parts is 0.05 to 5 mm.

[0025] The beneficial effects of the present invention are as follows: ① Compared with the prior art liquid absorbent core adopting a copper powder sintering structure, a braided copper mesh sintering structure or an etching structure, the present application adopts a production method combining processes such as "preparing slurry", "film making" and "high temperature treatment (high temperature sintering)" to produce the liquid absorbent core. Not only is the method simple and can realize continuous and large-scale production, but the obtained liquid absorbent core also has the characteristics of controllable overall thickness and size, and controllable hole type, aperture and layout of through holes, so that the liquid absorbent core can have excellent capillary microchannel characteristics and a very large dielectric capacity (that is, it has excellent heat conduction effect), and can also be made to have ultra-thin characteristics, so that the three-dimensional heat spreader made using the liquid absorbent core has the characteristics of good three-dimensional heat conduction effect, miniaturized structure, and ability to be tightly integrated with electronic devices, which well expands the application field of the three-dimensional heat spreader. ② This application adopts the processing method of "first making the absorbent core, and then assembling the absorbent core and the shell into one", which can greatly reduce the processing difficulty and complexity of the three-dimensional heat spreader, reduce processing costs, improve the yield of finished products, and realize continuous and large-scale production. In short, the production method of the three-dimensional heat spreader described in the present invention is simple, reasonable, and novel, and can realize continuous and large-scale production. The obtained three-dimensional heat spreader has a high yield rate of finished products, high three-dimensional heat conduction efficiency, miniaturized structure, good reliability, and long service life, which well meets the actual application needs, and has important practical value and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a flow chart of a method for manufacturing a three-dimensional vapor chamber according to the present invention;

[0027] Figure 2 This is a three-dimensional rendering of the three-dimensional vapor chamber of the present invention;

[0028] Figure 3 is a schematic diagram of the cross-sectional structure of the three-dimensional vapor chamber of the present invention;

[0029] Figure 4 Schematic diagram of the cross-sectional structure of the liquid absorbent core of the present invention;

[0030] Figure 5 The figure is a schematic diagram of the working principle of the three-dimensional heat sink described in the present invention.

[0031] Combined with the accompanying drawings, the following description is given:

[0032] 1. Shell; 10. Reflux cavity; 11. Upper part of shell; 12. Lower part of shell; 2. Liquid absorption core; 21. First part; 22. Second part; 3. Support column. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Embodiment 1:

[0034] As is known to all, a three-dimensional vapor chamber can achieve a three-dimensional heat conduction effect. To improve the three-dimensional flow field circulation performance of the three-dimensional vapor chamber, one of the key factors is to optimize the capillary microchannel structure of the liquid wick in the three-dimensional vapor chamber. This application aims to optimize and innovate the manufacturing method and structure of the liquid wick to further improve the three-dimensional heat conduction effect of the three-dimensional vapor chamber.

[0035] Please see attached Figure 1 To Attachment Figure 5 As shown, this embodiment 1 provides a method for manufacturing a three-dimensional vapor chamber, comprising the following manufacturing steps:

[0036] S1: Provide a shell 1, which is a closed shell structure formed by at least two parts. The inner cavity of the shell 1 is provided with a reflux cavity 10 that can contact the external heat source end. The cavity wall of the reflux cavity 10 is provided with through holes with quantitative or adjustable porosity and micro-nano pore size. The through holes are used for gas phase medium to pass through and for cooling liquid to reflux.

[0037] For details, please refer to the attached Figure 2 and attached Figure 3 As shown, the shell 1 in this embodiment 1 is formed by the upper shell part 11 and the lower shell part 12 being matched, and the reflux cavity 10 is integrally provided on the lower shell part 12. It is understandable that by designing the shell 1 to be formed by the upper shell part 11 and the lower shell part 12 being matched, it is convenient to place the components such as the absorbent core 2 in the inner cavity of the shell 1 in the post-process. Further, in order to facilitate the matching connection between the upper shell part 11 and the lower shell part 12, this embodiment 1 also designs the upper shell part 11 and the lower shell part 12 to be matched through a concave-convex plug-in structure, such as: a convex block can be integrally provided on one side of the upper shell part 11, and a groove that is plugged and matched with the convex block can be integrally provided on one side of the lower shell part 12.

[0038] In addition, ① when the three-dimensional heat spreader described in this embodiment 1 is applied to an electronic device, the above-mentioned "external heat source end" may refer to the control circuit board of the electronic device. Therefore, the above-mentioned "the reflow cavity 10 is in contact with the external heat source end" can be understood as: the external heat source end is attached to the outer wall of the outer shell 1 (specifically, the outer wall of the lower part 12 of the outer shell) and corresponds to the position of the reflow cavity 10. Furthermore, in order to facilitate heat transfer and heat dissipation at the external heat source end, this embodiment 1 also optimizes the molding method between the reflow cavity 10 and the outer shell 1 (specifically, the lower part 12 of the outer shell) as follows: the reflow cavity 10 is integrally molded in the lower part 12 of the outer shell (see attached Figure 3 As shown). In this way, the external heat source end can be directly attached to the outer surface of the cavity wall of the reflux cavity 10.

[0039] ② According to the working principle of the three-dimensional heat spreader, when the medium changes from gas phase to liquid phase, the liquid phase medium must flow back to a position close to the external heat source end, that is, flow back to the reflux cavity 10. Therefore, in order to ensure that the liquid phase medium quickly flows back to the reflux cavity 10, the porosity of the reflux cavity 10 should be no less than the porosity of the absorbent core 2 described below, and the aperture of the through hole on the reflux cavity 10 should be no less than the aperture of the through hole on the absorbent core 2 described below. However, the specific values ​​of the porosity of the reflux cavity 10 and the aperture of the through hole can be determined by the product design requirements, and this application does not impose any restrictions.

[0040] ③ When the three-dimensional heat spreader is actually used, the upper portion 11 of the shell and a position away from the reflux cavity 10 are usually connected with cooling fins (cooling liquid A or cooling gas flows in the cooling fins) to cool the medium in the gas phase.

[0041] S2: Make a liquid-absorbing core 2.

[0042] Specifically, the specific method for making the liquid absorbent core 2 in this embodiment 1 is as follows:

[0043] S21: 48 kg of fine powder (fine copper powder with a particle size of 100 μm), 10 kg of deionized water, 15 kg of organic solvent (dimethylformamide DMF), 10 kg of binder (composed of dextrin and α-starch in a weight ratio of 1:1), 2 kg of foaming agent (ammonium bicarbonate) and 15 kg of pore-forming agent (polyethylene) are mixed uniformly to prepare a slurry.

[0044] Description: ① The copper material is treated by an atomization powder making process to obtain the fine copper powder. The atomization powder making process is a powder preparation method that uses a rapidly sprayed molten fluid (metal or alloy liquid) to achieve atomization, forming the metal or alloy liquid into fine droplets, and then rapidly condensing it into a solid powder; it belongs to the conventional technical means in the field of metal powder making, so it will not be described in detail here. ② When water is used as the medium, in addition to the above-mentioned fine copper powder, the fine powder can also be fine silver powder or fine stainless steel powder. ③ In the raw material formula of the above-mentioned slurry, the solvent is used to dissolve the binder and disperse the fine powder and the pore-forming agent; the binder is used to bond the fine powder and the pore-forming agent; the foaming agent and the pore-forming agent are used to synergistically generate the through holes in the liquid absorbent core 2 structure, and the foaming agent can also reduce the surface tension of the slurry to facilitate stabilization of the slurry.

[0045] S22: uniformly coating the obtained slurry on a carrier to form a wet film, and subjecting the wet film to high temperature treatment to obtain a large liquid-absorbing core plate with a porous network structure.

[0046] Among them, the material of the above-mentioned carrier can preferably be glass or ceramic; the obtained slurry can be evenly coated on the carrier through a conventional coating process to form the wet film; the above-mentioned high-temperature treatment can preferably adopt a high-temperature sintering process, and the specific processing conditions of the high-temperature sintering process are: nitrogen is used as the protective gas, and the hydrogen-nitrogen mixed gas produced by the decomposition of ammonia is used as the reducing gas; sintering at 750-950°C for 30-120min (such as: sintering at 850°C for 100min).

[0047] In addition, according to processing requirements, before the above-mentioned high-temperature sintering process, the carrier carrying the wet film can also be dried to dry the solvent and improve the sintering speed and sintering quality of the subsequent process.

[0048] Based on the preferred raw material formula of the slurry, and the above-mentioned coating and high-temperature sintering process, the absorbent core large plate with a sheet-like overall appearance and a porous network structure at the microscopic level can be obtained. After testing, the thickness of the absorbent core large plate is 1mm, the porosity is 80%, and the apertures of the through holes in the absorbent core large plate are different, that is, the microstructure of the absorbent core large plate is a hierarchical structure (or a porous hierarchical structure), and the through holes in the absorbent core large plate are three-dimensional through holes with an average pore size of 30μm, and the through holes are also connected. That is, from the above, it can be seen that the absorbent core large plate has excellent capillary microchannel characteristics and a very large dielectric capacity, thereby achieving excellent heat conduction effects.

[0049] S23: Cut and shape the obtained absorbent core plate to obtain the absorbent core 2. It can be understood that this step is used to process the absorbent core plate into a plurality of absorbent cores 2 that conform to the shape of the inner cavity of the shell 1. Figure 4 A specific implementation structure of the liquid absorbent core 2 is shown, but the present application is not limited to this structure.

[0050] It can be understood that based on the above structural characteristics and functional characteristics of the large version of the absorbent core, the thickness of the absorbent core 2 is also 1mm, the porosity is also 80%, the apertures of the through holes in the absorbent core 2 are also different (that is, the microstructure of the absorbent core 2 is also a hierarchical structure), and the through holes in the absorbent core 2 are also three-dimensional through holes with an average aperture of 30μm, and the through holes are also connected to form a channel for the rapid flow of the liquid phase medium. That is: the absorbent core 2 has excellent capillary microchannel characteristics and a very large medium capacity, which can achieve excellent heat conduction effect.

[0051] S3: First, the liquid absorbent core 2 is placed at a preset position in the inner cavity of the shell 1, and then a support column 3 is arranged in the inner cavity of the shell 1 to support and limit the liquid absorbent core 2, and then they are combined into one by sintering, so as to obtain a three-dimensional heat spreader in which the channel is fixedly connected and communicated with the reflux cavity 10.

[0052] Specifically, because the shape of the absorbent core 2 and the inner cavity of the shell 1 are in conformity with each other, when the absorbent core 2 is placed in the inner cavity of the shell 1, the absorbent core 2 is close to the inner wall of the shell 1. This not only utilizes the assembly and sintering process between the absorbent core 2 and the shell 1, but also facilitates the cooling fins to cool the absorbent core 2, and facilitates the overall structure of the three-dimensional heat spreader to be miniaturized, stable and reliable. Moreover, based on the layout between the absorbent core 2 and the shell 1, the support column 3 is placed between two different parts of the absorbent core 2 (see the attached Figure 3 As shown), in order to achieve a stable support for the liquid absorbent core 2 and improve the sintering molding quality.

[0053] In addition, the support column 3 described in this embodiment can preferably adopt a porous network structure with the same material and microstructure as the liquid absorbent core 2, that is: the porosity of the support column 3 is 80%, the holes in the support column 3 are three-dimensional through holes with an average pore size of 30 μm, and the holes in the support column 3 are also interconnected to achieve connection with the channels in the liquid absorbent core 2, thereby further improving the reflux efficiency of the liquid medium.

[0054] In addition, the specific processing parameters for sintering the shell 1, the wick 2 and the support column 3 into one body in this embodiment 1 are: using nitrogen as the protective gas, and using the hydrogen-nitrogen mixed gas produced by the decomposition of ammonia as the reducing gas; sintering at 750-850°C for 30-90min (e.g., sintering at 800°C for 60min).

[0055] Based on the above description of the manufacturing method and structure of the three-dimensional vapor chamber described in this embodiment 1, it can be known that the working principle of the three-dimensional vapor chamber is:

[0056] Please see attached Figure 3 and attached Figure 5 As shown, when the reflow cavity 10 receives heat from the external heat source, the coolant (i.e., liquid medium) in the reflow cavity 10 is heated and vaporized into a high-temperature gaseous medium, and the high-temperature gaseous medium can enter and diffuse in the inner cavity of the shell 1 through the through hole. The flow direction of the high-temperature gaseous medium can be referred to in the attached Figure 5 As shown by the 2# arrow in the figure; when the high-temperature gas phase medium is cooled, it condenses to produce a coolant, and the coolant will flow back to the reflux cavity 10 through the channel and the through hole. The flow direction of the coolant flowing back to the reflux cavity 10 can be found in the attached Figure 5 As shown by the 1# arrow in the figure.

[0057] From the above, it can be seen that: ① Compared with the absorbent core in the prior art that adopts a copper powder sintering structure, a woven copper mesh sintering structure or an etching structure, the present application adopts a production method combining processes such as "preparing slurry", "film making", and "high-temperature treatment (high-temperature sintering)" to produce the absorbent core 2. This production method is not only simple and can realize continuous and large-scale production, but also makes the obtained absorbent core 2 have the characteristics of controllable overall thickness and size, and controllable hole type, aperture and layout of the through holes. Therefore, the absorbent core 2 can have excellent capillary microchannel characteristics and a very large dielectric capacity (that is, it has excellent heat conduction effect), and at the same time, it can also make the absorbent core 2 have ultra-thin characteristics, so that the three-dimensional heat spreader made using the absorbent core 2 has the characteristics of good three-dimensional heat conduction effect, miniaturized structure, and can be tightly integrated with electronic devices, which well expands the application field of the three-dimensional heat spreader. ② This application adopts the processing method of "first making the liquid absorbent core 2, and then assembling the liquid absorbent core 2 and the shell 1 into one", which can greatly reduce the processing difficulty and complexity of the three-dimensional heat sink, reduce processing costs, improve the yield of finished products, and realize continuous and large-scale production. Embodiment 2:

[0058] This embodiment 2 also provides a method for manufacturing a three-dimensional vapor chamber, and compared with embodiment 1, the differences of this embodiment 2 are mainly as follows: ① The slurry formula, coating thickness and high-temperature sintering process used in manufacturing the liquid absorbent core 2 in this embodiment 2 are different from those in embodiment 1. ② The structure of the support column 3 used in this embodiment 2 is different from that in embodiment 1.

[0059] Specifically, regarding the above-mentioned distinction ①;

[0060] In this embodiment 2, when making the liquid absorbent core 2, the slurry formula used is: 56Kg of fine powder (using fine copper powder with a particle size of 100μm), 5Kg of deionized water, 16Kg of organic solvent (using dimethylformamide DMF), 7Kg of binder (using polyurethane), 2Kg of foaming agent (using ammonium bicarbonate) and 14Kg of pore-forming agent (using polyvinyl chloride) are mixed evenly to obtain the slurry. The coating process used is the same as that of embodiment 1, but the film thickness is different and is determined according to the design requirements. The high-temperature sintering process used is: nitrogen is used as the protective gas, and the hydrogen-nitrogen mixed gas produced by the decomposition of ammonia is used as the reducing gas; sintering at 900°C for 60min.

[0061] Based on the slurry formula, coating and high-temperature sintering process used in this embodiment 2, combined with the same cutting and shaping process as in embodiment 1, the absorbent core 2 with a porous network structure can be obtained. And after testing, the thickness of the absorbent core 2 is 2mm, the porosity is 75%, the pore sizes of the through holes in the absorbent core 2 are different (that is, the microstructure of the absorbent core 2 is a hierarchical structure), and the through holes in the absorbent core 2 are three-dimensional through holes with an average pore size of 40μm, and the through holes are also connected to form a channel for the rapid flow of the liquid phase medium. That is: the absorbent core 2 obtained in this embodiment 2 also has excellent capillary microchannel characteristics and a very large medium capacity, which can achieve excellent heat conduction effect.

[0062] Regarding the above-mentioned distinction ②;

[0063] The material and microstructure of the support column 3 used in this embodiment 2 are the same as the material and microstructure of the liquid absorbent core 2 prepared in this embodiment 2, that is, the porosity of the support column 3 is 75%, the holes in the support column 3 are three-dimensional through holes with an average pore size of 40 μm, and the holes in the support column 3 are also connected to achieve connection with the channels in the liquid absorbent core 2, thereby further improving the reflux efficiency of the liquid medium.

[0064] In addition to the above two differences, the following aspects are adopted in the present embodiment 2 when manufacturing the three-dimensional heat spreader: the structure of the outer shell 1, the shape of the liquid absorbent core 2, and the arrangement of the outer shell 1, the liquid absorbent core 2 and the support column 3, as well as the sintering molding process, etc.; all of which are the same as those in embodiment 1, so they will not be elaborated here. Embodiment 3:

[0065] This embodiment 3 also provides a method for manufacturing a three-dimensional vapor chamber, and compared with embodiment 1, the differences of this embodiment 3 are mainly as follows: ① The slurry formula, coating thickness and high-temperature sintering process used in manufacturing the liquid absorbent core 2 in this embodiment 3 are different from those in embodiment 1. ② The structure of the support column 3 used in this embodiment 3 is different from that in embodiment 1.

[0066] Specifically, regarding the above-mentioned distinction ①;

[0067] In this embodiment 3, when making the liquid absorbent core 2, the slurry formula used is: 52Kg of fine powder (using fine copper powder with a particle size of 100μm), 10Kg of deionized water, 14Kg of organic solvent (using dimethylformamide DMF), 9Kg of binder (composed of dextrin and α-starch in a weight ratio of 1:2), 2Kg of foaming agent (using UNICELL-MS series expansion agent, such as: UNICELL-MS205D expansion agent) and 13Kg of pore-forming agent (using polypropylene) are mixed evenly to obtain the slurry. The coating process used is the same as that of embodiment 1, but the film thickness is different and is determined according to the design requirements. The high-temperature sintering process used is: nitrogen is used as the protective gas, and the hydrogen-nitrogen mixed gas produced by the decomposition of ammonia is used as the reducing gas; sintering at 800°C for 120min.

[0068] Based on the slurry formula, coating and high-temperature sintering process used in this embodiment 3, combined with the same cutting and shaping process as in embodiment 1, the absorbent core 2 with a porous network structure can be obtained. And after testing, the thickness of the absorbent core 2 is 1mm, the porosity is 70%, the pore sizes of the through holes in the absorbent core 2 are different (that is, the microstructure of the absorbent core 2 is a hierarchical structure), and the through holes in the absorbent core 2 are three-dimensional through holes with an average pore size of 30μm, and the through holes are also connected to form a channel for the rapid flow of the liquid phase medium. That is: the absorbent core 2 obtained in this embodiment 3 also has excellent capillary microchannel characteristics and a very large medium capacity, which can achieve excellent heat conduction effect.

[0069] Regarding the above-mentioned distinction ②;

[0070] The material and microstructure of the support column 3 used in this embodiment 3 are the same as the material and microstructure of the liquid absorbent core 2 prepared in this embodiment 3, that is, the porosity of the support column 3 is 70%, the holes in the support column 3 are three-dimensional through holes with an average pore size of 30 μm, and the holes in the support column 3 are also connected to achieve connection with the channels in the liquid absorbent core 2, thereby further improving the reflux efficiency of the liquid medium.

[0071] In addition to the above two differences, the following aspects are adopted in the present embodiment 3 when manufacturing the three-dimensional heat spreader: the structure of the outer shell 1, the shape of the liquid absorbent core 2, and the arrangement of the outer shell 1, the liquid absorbent core 2 and the support column 3, as well as the sintering molding process, etc.; all of which are the same as those in embodiment 1, so they will not be elaborated here. Embodiment 4:

[0072] Embodiment 4 provides a three-dimensional heat spreader, which is manufactured using the manufacturing method of the three-dimensional heat spreader described in Embodiment 1.

[0073] Specifically, the specific structure of the three-dimensional heat sink described in this embodiment 4 is as follows: Figure 2 To Attachment Figure 5 As shown, the three-dimensional heat spreader includes a shell 1, a liquid wick 2 and a support column 3, wherein the shell 1 is a closed shell structure formed by combining at least two parts, a reflux cavity 10 capable of contacting an external heat source end is provided in the inner cavity of the shell 1, and a through hole with a quantitative or adjustable porosity and a micro-nano pore size is provided on the cavity wall of the reflux cavity 10; the liquid wick 2 is a porous network structure, and is fixedly arranged in the inner cavity of the shell 1 in a conformal manner with the shape of the inner cavity of the shell 1, and the liquid wick The porosity of the core 2 is 80%, and the holes in the absorbent core 2 are through holes with a pore size of micro-nano level (such as an average pore size of 30 μm). The through holes are also connected to form a channel for rapid flow of the liquid phase medium, and the channel is connected to the reflux cavity 10; the support column 3 also adopts a porous network structure and is arranged in the inner cavity of the shell 1 to support and limit the absorbent core 2; and the holes on the support column 3 (porosity of 80%, average pore size of 30 μm) are also connected to the channel.

[0074] Further, based on the shape of the shell 1, the specific implementation structure of the liquid absorbent core 2 is: Figure 3 and attached Figure 4 As shown, the absorbent core 2 includes a first part 21 and two second parts 22 respectively connected to both ends of the first part 21. It can be understood that the first part 21 and the two second parts 22 are both porous network structures provided with a plurality of through holes with pore sizes of micro-nano level (such as an average pore size of 30 μm). The through holes on the first part 21 and the two second parts 22 are connected to form the channel, and the two second parts 22 are also respectively connected to the opposite sides of the reflux cavity 10, so that the channel is connected to the reflux cavity 10.

[0075] Furthermore, the thickness of the first part 21 and the two second parts 22 are both 1 mm. The first part 21 adopts a sheet structure with a corrugated cross-sectional shape, and the two second parts 22 both adopt a sheet structure with an inverted L-shaped cross-sectional shape, and the two second parts 22 are also arranged in a mirror-symmetrical manner. From the shapes and sizes of the first part 21 and the second part 22, it can be seen that the liquid absorbent core 2 and the three-dimensional heat spreader made thereof have the characteristics of ultra-thin structure / miniaturization, which can enable the three-dimensional heat spreader to be tightly integrated with other electronic devices to achieve efficient thermal coupling and heat diffusion effects.

[0076] In summary, the three-dimensional heat spreader described in Example 4 has excellent three-dimensional heat conduction efficiency, and the structure is miniaturized, which can be closely integrated with other electronic devices, thereby achieving efficient thermal coupling and heat diffusion effects. In addition, the three-dimensional heat spreader also has the advantages of high finished product yield, good reliability, and long service life, which well meets the actual application needs, and has important practical value and broad application prospects.

[0077] Final note: The prefixes "first", "second", etc. (such as the first part, the second part, etc.) to the component names in this application specification are only for the convenience of description and are not used to limit the scope of implementation of this application.

[0078] To sum up, the manufacturing method of the three-dimensional heat spreader described in the present application is simple, reasonable and novel, and can realize continuous and large-scale production. The obtained three-dimensional heat spreader has a high finished product yield, high three-dimensional heat conduction efficiency, miniaturized structure, good reliability and long service life, which meets the actual application needs very well, has important practical value and broad application prospects.

[0079] Many specific details are described in the above description to facilitate a full understanding of the present invention. However, the above description is only a preferred embodiment of the present invention. The present invention can be implemented in many other ways different from those described herein, so the present invention is not limited to the specific implementation disclosed above. At the same time, any person familiar with the art can make many possible changes and modifications to the technical solution of the present invention using the methods and technical contents disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the scope of protection of the technical solution of the present invention.

Claims

1. A method for manufacturing a three-dimensional heat sink, characterized in that: The production steps include: S1: providing a housing (1), wherein the housing (1) is a closed shell structure formed by combining at least two parts, wherein a reflux cavity (10) capable of contacting an external heat source end is provided in an inner cavity of the housing (1), and a through hole with a quantitative or adjustable porosity and a micro-nano-scale pore size is provided on a cavity wall of the reflux cavity (10); S2: preparing a liquid absorbent core (2): by weight percentage, 45% to 60% of fine powder, 15% to 30% of solvent, 5% to 15% of binder, 1% to 3% of foaming agent and 10% to 20% of pore-forming agent are mixed evenly to prepare a slurry; wherein the fine powder is prepared by an atomization powder making process from a material having thermal conductivity and not reacting with a medium; the obtained slurry is evenly coated on a carrier to form a wet film, and the wet film is subjected to high temperature treatment to prepare a liquid absorbent core plate with a porous network structure; the obtained liquid absorbent core plate is then cut and shaped to prepare the liquid absorbent core (2); and the porosity of the liquid absorbent core (2) is 40% to 90%, and the pores in the liquid absorbent core (2) are through holes with a pore size of micro-nanoscale, and the through holes are also interconnected to form channels for rapid flow of the liquid phase medium; S3: placing the liquid absorbent core (2) at a preset position in the inner cavity of the shell (1), and then combining them into one body by sintering, thereby obtaining a three-dimensional heat spreader in which the channel is fixedly connected and communicated with the reflux cavity (10).

2. The method for manufacturing a three-dimensional vapor chamber according to claim 1, characterized in that: In the above S2, the fine powder material is copper powder with a particle size of 1 to 150 μm; The solvent comprises deionized water and an organic solvent, wherein the organic solvent is selected from at least one of methanol, ethanol, propanol, isopropanol, acetone, toluene, xylene, terpineol, triethanolamine, dimethylformamide, isophorone and dibasic acid esters; The binder is selected from at least one of dextrin, α-starch, polyurethane, nitrocellulose, polyvinyl acetate, polyacrylate, phenolic resin, polyvinyl acetate resin and urea-formaldehyde resin; The foaming agent is selected from at least one of ammonium bicarbonate and UNICELL-MS series expansion agents; The pore former is selected from at least one of polyethylene, polypropylene, polyvinyl chloride and polystyrene.

3. The method for manufacturing a three-dimensional vapor chamber according to claim 1, characterized in that: In the above S2, the material of the carrier is glass or ceramic; The wet film is subjected to high temperature treatment by a high temperature sintering process, and the specific processing conditions of the high temperature sintering process are: nitrogen is used as the protective gas, and a hydrogen-nitrogen mixed gas produced by the decomposition of ammonia is used as the reducing gas; and sintering is performed at 750-950° C. for 30-120 minutes.

4. The method for manufacturing a three-dimensional vapor chamber according to claim 1, characterized in that: In the above S2, the large plate of the liquid absorbent core is a sheet-like structure with a thickness of 0.05 to 5 mm; the shape of the liquid absorbent core (2) is matched with the shape of the inner cavity of the shell (1).

5. The method for manufacturing a three-dimensional vapor chamber according to claim 1, characterized in that: The microstructures of the large absorbent core plate and the absorbent core (2) are both hierarchical structures, and the holes in the large absorbent core plate and the absorbent core (2) are all three-dimensional through holes with an average pore size of 2 to 500 μm.

6. The method for manufacturing a three-dimensional vapor chamber according to claim 1, characterized in that: In the above S3, the specific processing conditions of the sintering are: using nitrogen as the protective gas, using the hydrogen and nitrogen mixed gas generated by the decomposition of ammonia as the reducing gas; and sintering at 750-850° C. for 30-90 min.

7. The method for manufacturing a three-dimensional vapor chamber according to claim 1, characterized in that: In the above S3, after the absorbent core (2) is placed at a preset position in the inner cavity of the shell (1), a support column (3) is provided in the inner cavity of the shell (1) for supporting and limiting the absorbent core (2), and then sintered and combined into one body.

8. The method for manufacturing a three-dimensional vapor chamber according to claim 7, characterized in that: The support column (3) also adopts a porous network structure, and the porosity of the support column (3) is 40% to 90%, and the pores in the support column (3) are three-dimensional through holes with an average pore diameter of 2 to 500 μm.

9. A three-dimensional heat sink, characterized in that: The three-dimensional heat spreader is manufactured by the manufacturing method of any one of claims 1 to 8.

10. The three-dimensional vapor chamber according to claim 9, characterized in that: The absorbent core (2) comprises a first part (21) and two second parts (22) respectively connected to two ends of the first part (21); the through holes on the first part (21) and the two second parts (22) are connected to form the channel; and the two second parts (22) are also respectively connected to two opposite sides of the reflow cavity (10) so that the channel is connected to the reflow cavity (10); In addition, the thickness of the first part (21) and the two second parts (22) are both 0.05-5 mm.

Images