Vapor chamber and preparation method thereof
By designing parallel capillary segments in the ultrathin heat exchange plate, the problem of reduced water absorption rate and liquid absorption caused by the decrease in capillary thickness was solved, and better heat transfer performance was achieved.
Patent Information
- Application Number
- CN202511487601.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-16
- Publication Date
- 2025-12-23
AI Technical Summary
Due to the reduced capillary thickness, ultra-thin heat exchange plates have lower water absorption rates and liquid absorption volumes, resulting in poor heat transfer performance.
A capillary structure is formed by arranging capillary segments that are parallel to each other and equally spaced along the first direction. The gap width between two adjacent capillary segments is 10~500μm, and the width of each capillary segment along the first direction is the same and is 10~500μm, forming a three-dimensional interconnected hole structure. The capillary structure is prepared by screen printing.
Under conditions of small thickness, the water absorption rate and liquid absorption of the capillary structure are enhanced, multi-channel gas-liquid separation is achieved, and the working fluid transport effect and heat transfer performance are improved.
Smart Images
Figure CN121185104A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of heat dissipation technology, and in particular to a heat spreader and its preparation method. Background Technology
[0002] The high-frequency and high-speed development of electronic components and integrated circuit technology has led to the generation of a large amount of heat during the operation of electronic components. For example, the heat flux density of a computer CPU during operation has reached 60~100 W / cm³. 2 In semiconductor lasers, the figure can even reach 10. 3 W / cm 2 The reliability of electronic devices is extremely sensitive to temperature; for every 1°C increase in device temperature above 70-80°C, reliability decreases by 5%.
[0003] High heat flux poses a significant threat to the reliability of electronic components, making heat dissipation a key issue in the miniaturization of electronic products. To ensure the normal operation of electronic components, heat sinks are typically installed on them for heat dissipation. A vapor chamber with good thermal conductivity is then placed between the heat sink and the electronic component. The vapor chamber's function is to evenly distribute the heat from the heated electronic component before it is dissipated through the heat sink.
[0004] A vapor chamber is a heat-conducting component that achieves rapid heat transfer through the phase change of its internal working fluid. It mainly consists of a plate with an inner cavity, a sealing head, a liquid wick, and a heat transfer medium. Among these, the capillary structure of the liquid wick directly affects the performance of the vapor chamber, requiring strong capillary force and low water flow resistance.
[0005] In related technologies, there are many types of liquid wicks with capillary structures in heat spreaders, such as foamed copper, copper mesh, composite copper mesh, and etched capillary structures. However, the manufacturing cost of these liquid wicks is relatively high and the process is relatively complex, such as foamed copper or composite copper mesh. Moreover, because the liquid wicks such as foamed copper and copper mesh / composite copper mesh have a large thickness, it is impossible to develop heat spreaders to be thinner.
[0006] As electronic products continue to trend towards miniaturization, the dimensions of other components are becoming smaller and thinner. This places increasingly stringent requirements on the thickness of vapor chambers, leading to the development of ultra-thin vapor chambers with thicknesses as low as 240μm (below 280μm). These ultra-thin vapor chambers, while maintaining heat transfer performance, require even thinner wicks, such as wicks with thicknesses of 80μm or even 50μm. However, due to the reduced capillary thickness, the water absorption rate and volume of ultra-thin vapor chambers decrease, ultimately resulting in poorer heat transfer performance. Summary of the Invention
[0007] To address the shortcomings of the aforementioned related technologies, this invention proposes a novel heat spreader and its preparation method, thereby solving the problem that ultra-thin heat spreaders in related technologies suffer from reduced water absorption rate and liquid absorption volume due to their reduced capillary thickness, and also exhibit poor heat transfer performance.
[0008] To solve the above-mentioned technical problems, in a first aspect, the present invention provides a temperature distribution plate, which includes a plate body having an inner cavity and a capillary structure formed on the inner side of the plate body; The capillary structure includes a plurality of capillary segments that are parallel to each other and equally spaced along a first direction; each capillary segment extends along a second direction, the width of the gap between two adjacent capillary segments is 10~500μm, and the width of each capillary segment extending along the first direction is the same and is 10~500μm; wherein, the first direction and the second direction are perpendicular to each other.
[0009] Preferably, the capillary structure is a three-dimensional interconnected pore structure with a pore diameter less than or equal to 200 μm and a porosity of 40-80%.
[0010] Preferably, the pore size is 10~100μm.
[0011] Preferably, the plate body includes an upper cover plate and a lower cover plate that is fixed to the upper cover plate and together with the upper cover plate forms the inner cavity; the capillary structure is formed on the side of the upper cover plate near the lower cover plate.
[0012] Preferably, the capillary structure extends to a height of 20~300μm along the upper cover plate toward the lower cover plate.
[0013] Preferably, the capillary structure extends to a height of 40~150μm along the direction from the upper cover plate toward the lower cover plate.
[0014] Preferably, the capillary structure is formed on the upper cover plate by screen printing; the line width and line spacing of the screen in the screen printing machine are both 10~500μm.
[0015] Secondly, the present invention provides a method for preparing the heat spreader as described above, the method comprising the following steps: The line width and line spacing of the screen are set according to the dimensions corresponding to the capillary structure. The screen is installed on a screen printing machine, and then copper paste is printed onto the top cover plate by screen printing. The copper paste printed onto the upper cover plate is sequentially dried, de-adhesive-removed, and sintered to obtain the capillary structure. The lower cover plate is fixed to the side of the upper cover plate where the capillary structure is located to obtain the temperature equalization plate.
[0016] Preferably, the copper paste is prepared by mixing 10-80 wt% copper powder, 5-70 wt% pore-forming agent, 1-10 wt% adhesive and 5-40 wt% solvent.
[0017] Preferably, the copper powder is any one of atomized copper powder, electrolytic copper powder, reduced copper powder, and plasma-processed copper powder; the shape of the copper powder is any one of dendritic, flake, and spherical; the particle size of the copper powder is 100nm~100μm, and the purity of the copper powder is greater than or equal to 98%.
[0018] Preferably, the pore-forming agent is any one of organic solid small molecules, inorganic salts, copper salts, and copper oxides; the particle size of the pore-forming agent is in the micrometer range.
[0019] Preferably, the adhesive is one or more of acrylic resins and epoxy resins.
[0020] Preferably, the solvent is one or more of toluene, xylene, acetone, ethanol, and terpineol.
[0021] Preferably, the viscosity of the copper paste is 10,000 to 100,000 mPa·s.
[0022] Preferably, the drying is carried out in an oven at a temperature of 80~150℃ for 10~120 minutes; the glue removal is carried out in a glue removal furnace at a temperature of 300~650℃ with a first protective atmosphere for 10~120 minutes; the sintering is carried out in a sintering furnace at a temperature of 700~900℃ with a second protective atmosphere for 10~120 minutes; the first protective atmosphere and the second protective atmosphere are one or more of nitrogen, hydrogen and argon.
[0023] Compared with related technologies, the heat exchange plate of the present invention defines a capillary structure comprising multiple capillary segments that are parallel to each other and equally spaced along a first direction. The width of the gap between two adjacent capillary segments is 10~500μm, and the width of each capillary segment along the first direction is the same and is 10~500μm. Thus, even with a relatively thin capillary structure, the capillary structure can enhance the water absorption rate and liquid absorption volume according to the size of the gap between two adjacent capillary segments. It can also form a gaseous working fluid transport channel, realize multi-channel gas-liquid separation, enhance the gas-liquid working fluid transport effect, improve the mass transfer permeability of the heat exchange plate, and ultimately improve the heat transfer performance of the heat exchange plate. Attached Figure Description
[0024] The present invention will now be described in detail with reference to the accompanying drawings. The above and other aspects of the present invention will become clearer and more readily understood through the detailed description following the accompanying drawings. In the drawings: Figure 1 This is a plan view of a heat spreader provided in an embodiment of the present invention, including an upper cover plate and a capillary structure; Figure 2 A scanning electron microscope image of the capillary structure provided in an embodiment of the present invention; Figure 3 for Figure 2 A partially enlarged diagram. Detailed Implementation
[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application, are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.
[0026] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0028] This invention provides a temperature distribution plate, which includes a plate body with an inner cavity and a capillary structure formed on one inner side of the plate body.
[0029] The plate body includes an upper cover plate and a lower cover plate that is fixed to the upper cover plate and together with the upper cover plate forms the inner cavity; such as Figure 1 As shown, the capillary structure 2 is formed on the side of the upper cover plate 1 near the lower cover plate.
[0030] Combination Figures 1 to 3 As shown, the capillary structure 2 includes a plurality of capillary segments 21 that are parallel to each other and equally spaced along a first direction. Each capillary segment 21 extends along a second direction, and the width of the gap 211 between two adjacent capillary segments 21 is 10~500μm. The width of the capillary segments 21 along the first direction is the same and is 10~500μm. The first direction is as follows... Figure 1 In the X-axis, the second direction is as follows Figure 1 The Y-axis in the equation.
[0031] The capillary structure is a three-dimensional interconnected pore structure with a pore diameter less than or equal to 200 μm. Preferably, the pore diameter of the three-dimensional interconnected pore structure is 10~100 μm. The three-dimensional interconnected pores 22 in the three-dimensional interconnected pore structure are as follows: Figure 3 As shown, the porosity of the three-dimensional interconnected hole structure is 40-80%, which is the total volume of the pores / (total volume of the pores + actual volume of the metal in the capillary structure) × 100%. The three-dimensional interconnected hole structure is a three-dimensional interconnected hole structure, that is, a through-hole structure formed by at least three different directions interconnected with each other.
[0032] The capillary structure extends to a height of 20-300 μm along the direction of the upper cover plate near the lower cover plate; preferably, the capillary structure extends to a length of 40-150 μm along the direction of the upper cover plate near the lower cover plate. The capillary structure is formed on the upper cover plate by screen printing; the line width and line spacing of the screen in the screen printing machine are both 10~500μm.
[0033] The gap between two adjacent capillary segments is hereinafter referred to as a gap. When the gap is 10~50μm, due to the narrow width of the gap, a capillary-like structure is formed. The mass transfer resistance of this channel is weak, which can enhance the capillary liquid absorption and the transmission rate of the working fluid (such as water), increase the permeability of the capillary structure, thereby enhancing the capillary performance of the liquid absorption core and acting as a vapor chamber. When the gap is 10~50μm, the channel formed by the gap not only enhances the capillary permeability but also plays a partial role in gas-liquid separation, increasing the volume of the vapor chamber, and simultaneously enhancing the working fluid and heat transfer of the heat exchanger. When the gap is 100~500μm, due to the larger width of the gap, the channel formed is used for the transmission of the gas phase working fluid, forming a multi-channel gas-liquid separation, further increasing the volume of the vapor chamber and enhancing the transmission rate of the working fluid.
[0034] The method for preparing the heat spreader includes the following steps: The first step: Set the line width and line spacing of the screen according to the dimensions corresponding to the capillary structure.
[0035] The different widths, ranging from 10 to 500 μm, and the line spacing, ranging from 10 to 500 μm, are combined in various ways, such as 10-10 μm line width and line spacing, 30-30 μm line width and line spacing, 50-50 μm line width and line spacing, 100-100 μm line width and line spacing, 200-200 μm line width and line spacing, 300-150 μm line width and line spacing, 300-300 μm line width and line spacing, and 500-500 μm line width and line spacing.
[0036] The screen is installed on a screen printing machine, and then copper paste is printed onto the top cover plate by screen printing.
[0037] The copper paste has a set porosity and a certain particle size range, including copper powder of a certain fixed shape, a pore-forming agent with a certain particle size range, etc. The copper paste has a certain solid content, such as 70~85%, and a certain viscosity, such as greater than or equal to 10000 mPa·s.
[0038] The second step: Install the screen with the set line width and spacing onto the screen printing machine, and print the copper paste onto the top cover of the heat spreader using screen printing.
[0039] The third step: The copper paste printed onto the top cover plate is dried, de-adhesived, and sintered sequentially to obtain the capillary structure.
[0040] The drying process is carried out in an oven at a temperature of 80~150℃ for 10~120 minutes. The purpose is to completely dry the solvent.
[0041] The adhesive removal is carried out in an adhesive removal furnace at a temperature of 300~650℃ with a first protective atmosphere, and the removal time is 10~120 minutes. The purpose is to remove the adhesive.
[0042] The sintering is carried out in a sintering furnace at a temperature of 700~900℃ with a second protective atmosphere, and the sintering time is 10~120 minutes. The purpose is to give the copper paste a three-dimensional interconnected pore structure or a three-dimensional network structure with high porosity.
[0043] The first protective atmosphere and the second protective atmosphere are one or more of nitrogen (N2), hydrogen (H2) and argon (Ar).
[0044] The copper paste is prepared by mixing 10-80 wt% copper powder, 5-70 wt% pore-forming agent, 1-10 wt% adhesive, and 5-40 wt% solvent. Preferably, the copper paste is composed of 20-65 wt% copper powder, 10-60 wt% pore-forming agent, 3-8 wt% adhesive, and 15-30 wt% solvent.
[0045] The copper powder is any one of atomized copper powder, electrolytic copper powder, reduced copper powder, and plasma-processed copper powder. The shape of the copper powder is any one of dendritic, flake, and spherical powder. The particle size of the copper powder is submicron or micron, such as 100nm~100μm. The purity of the copper powder is greater than or equal to 98%.
[0046] The pore-forming agent is any one of organic solid small molecules, inorganic salts, copper salts, and copper oxides; the particle size of the pore-forming agent is in the micrometer range.
[0047] The adhesive is one or more of acrylic resins and epoxy resins.
[0048] The solvent is one or more of toluene, xylene, acetone, ethanol, and terpineol.
[0049] The viscosity of the copper paste is 10,000~100,000 mPa•s. This gives the copper paste a high viscosity, making it less likely to flow after being printed onto the heat spreader.
[0050] The fourth step: The lower cover plate is fixed to the side of the upper cover plate where the capillary structure is located, to obtain the temperature equalization plate.
[0051] Compared with related technologies, the heat spreader in this embodiment defines a capillary structure comprising multiple capillary segments arranged parallel to each other and at equal intervals along a first direction. The width of the gap between two adjacent capillary segments is 10~500μm, and the width of each capillary segment along the first direction is the same, also 10~500μm. Thus, even with a relatively thin capillary structure, the capillary structure can enhance the water absorption rate and liquid absorption capacity based on the width of the gap between two adjacent capillary segments. It can also form a gaseous working fluid transport channel, achieving multi-channel gas-liquid separation, enhancing the gas-liquid working fluid transport effect, and improving the mass transfer permeability of the heat spreader, ultimately improving the heat transfer performance of the heat spreader. Furthermore, the capillary structure in this embodiment can be implemented simply by designing specific line widths and spacings on the mesh plate, resulting in a simpler process and lower cost.
[0052] To better understand the preparation method and effects of the capillary structure in this invention, several specific embodiments and comparative examples will be described below.
[0053] Example 1 The method for preparing the capillary structure in this embodiment is as follows: A copper paste is prepared, wherein the copper powder is 60 wt% dendritic copper powder with a particle size of 10 μm, the pore-forming agent is 10 wt% ammonium chloride powder, the adhesive is 7% PMMA (polymethyl methacrylate), and the solvent is 23% terpineol. The paste is thoroughly stirred to prepare a copper paste with a viscosity ≥30000 mPa•s. A screen with a pattern designed with a line width and spacing of 10 μm-10 μm is installed in a screen printing machine. The copper paste is printed onto the upper cover of the heat spreader using screen printing. The screen is then placed in an oven at 110°C for 30 minutes and completely dried in air. The upper cover of the heat spreader is then placed sequentially into a desizing furnace and a sintering furnace with a protective atmosphere. The desizing furnace has a temperature of 500°C, a desizing time of 60 minutes, and a N2 protective atmosphere. The sintering furnace has a temperature of 800°C, a time of 60 minutes, and a N2 and H2 protective atmosphere.
[0054] Example 2 The method for preparing the capillary structure in this embodiment is as follows: Prepare copper paste, which is the same as the copper paste in Example 1; install a screen printing plate with a pattern of 30μm-30μm line width and line spacing in a screen printing machine, and print the copper paste onto the upper cover plate of the heat spreader by screen printing. Then place it in an oven at 110℃ for 30 minutes to dry completely in air atmosphere. Then place the upper cover plate of the heat spreader into a desizing furnace and a sintering furnace with a protective atmosphere in sequence. The temperature of the desizing furnace is 500℃, the desizing time is 60 minutes, and the protective atmosphere is N2. The temperature of the sintering furnace is 800℃, the time is 60 minutes, and the protective atmosphere is N2 and H2 atmosphere.
[0055] Example 3 The method for preparing the capillary structure in this embodiment is as follows: Prepare copper paste, which is the same as the copper paste in Example 1; install a screen printing plate with a pattern of 50μm-50μm line width and line spacing in a screen printing machine, and print the copper paste onto the upper cover plate of the heat spreader by screen printing. Then place it in an oven at 110℃ for 30 minutes to dry completely in air atmosphere. Then place the upper cover plate of the heat spreader into a desizing furnace and a sintering furnace with a protective atmosphere in sequence. The temperature of the desizing furnace is 500℃, the desizing time is 60 minutes, and the protective atmosphere is N2. The temperature of the sintering furnace is 800℃, the time is 60 minutes, and the protective atmosphere is N2 and H2 atmosphere.
[0056] Example 4 The method for preparing the capillary structure in this embodiment is as follows: Prepare copper paste, which is the same as the copper paste in Example 1; install a screen printing plate with a pattern of 80μm-80μm line width and line spacing in a screen printing machine, and print the copper paste onto the upper cover plate of the heat spreader by screen printing. Then place it in an oven at 110℃ for 30 minutes to dry completely in air atmosphere. Then place the upper cover plate of the heat spreader into a desizing furnace and a sintering furnace with a protective atmosphere in sequence. The temperature of the desizing furnace is 500℃, the desizing time is 60 minutes, and the protective atmosphere is N2. The temperature of the sintering furnace is 800℃, the time is 60 minutes, and the protective atmosphere is N2 and H2 atmosphere.
[0057] Example 5 The method for preparing the capillary structure in this embodiment is as follows: Prepare copper paste, which is the same as the copper paste in Example 1; install a screen printing plate with a pattern of 100μm-100μm line width and line spacing in a screen printing machine, and print the copper paste onto the upper cover plate of the heat spreader by screen printing. Then place it in an oven at 110℃ for 30 minutes to dry completely in air atmosphere. Then place the upper cover plate of the heat spreader into a desizing furnace and a sintering furnace with a protective atmosphere in sequence. The temperature of the desizing furnace is 500℃, the desizing time is 60 minutes, and the protective atmosphere is N2. The temperature of the sintering furnace is 800℃, the time is 60 minutes, and the protective atmosphere is N2 and H2 atmosphere.
[0058] Example 6 The method for preparing the capillary structure in this embodiment is as follows: Prepare copper paste, which is the same as the copper paste in Example 1; install a screen with a pattern designed with a line width and line spacing of 200μm-200μm in a screen printing machine, and print the copper paste onto the upper cover of the heat spreader by screen printing. Then, place it in an oven at 110℃ for 30 minutes to dry completely in air atmosphere. Then, place the upper cover of the heat spreader into a desizing furnace and a sintering furnace with a protective atmosphere in sequence. The temperature of the desizing furnace is 500℃, the desizing time is 60 minutes, and the protective atmosphere is N2. The temperature of the sintering furnace is 800℃, the time is 60 minutes, and the protective atmosphere is N2 and H2 atmosphere.
[0059] Example 7 The method for preparing the capillary structure in this embodiment is as follows: Prepare copper paste, which is the same copper paste used in Example 1; install a screen printing plate with a pattern designed with a line width and line spacing of 300μm-150μm in a screen printing machine, and print the copper paste onto the upper cover plate of the heat spreader by screen printing. Then, place it in an oven at 110℃ for 30 minutes to dry completely in air atmosphere. Then, place the upper cover plate of the heat spreader into a desizing furnace and a sintering furnace with a protective atmosphere in sequence. The temperature of the desizing furnace is 500℃, the desizing time is 60 minutes, and the protective atmosphere is N2. The temperature of the sintering furnace is 800℃, the time is 60 minutes, and the protective atmosphere is N2 and H2 atmosphere.
[0060] Example 8 The method for preparing the capillary structure in this embodiment is as follows: Prepare copper paste, which is the same copper paste as in Example 1; install a screen printing plate with a pattern of 300μm-300μm line width and line spacing in a screen printing machine, and print the copper paste onto the top cover plate of the heat spreader by screen printing. Then place it in an oven at 110℃ for 30 minutes to dry completely in air atmosphere. Then place the top cover plate of the heat spreader into a desizing furnace and a sintering furnace with a protective atmosphere in sequence. The temperature of the desizing furnace is 500℃, the desizing time is 60 minutes, and the protective atmosphere is N2. The temperature of the sintering furnace is 800℃, the time is 60 minutes, and the protective atmosphere is N2 and H2 atmosphere.
[0061] Example 9 The method for preparing the capillary structure in this embodiment is as follows: Prepare copper paste, which is the same as the copper paste in Example 1; install a screen printing plate with a pattern of 500μm-500μm line width and line spacing in a screen printing machine, and print the copper paste onto the top cover plate of the heat spreader by screen printing. Then place it in an oven at 110℃ for 30 minutes to dry completely in air atmosphere. Then place the top cover plate of the heat spreader into a desizing furnace and a sintering furnace with a protective atmosphere in sequence. The temperature of the desizing furnace is 500℃, the desizing time is 60 minutes, and the protective atmosphere is N2. The temperature of the sintering furnace is 800℃, the time is 60 minutes, and the protective atmosphere is N2 and H2 atmosphere.
[0062] Example 10 The method for preparing the capillary structure in this embodiment is as follows: A copper paste is prepared, comprising 50 wt% dendritic copper powder with a particle size of 10 μm, 24 wt% ammonium chloride powder as the pore-forming agent, 5% PMMA as the adhesive, and 21% terpineol as the solvent. The paste is thoroughly stirred to obtain a viscosity ≥30000 mPa•s. A screen with a pattern designed with a line width and spacing of 100 μm-100 μm is installed in a screen printing machine. The copper paste is printed onto the upper cover of the heat spreader using screen printing. The screen is then placed in an oven at 110°C for 30 minutes and completely dried in air. The upper cover of the heat spreader is then sequentially placed in a desizing furnace and a sintering furnace with a protective atmosphere. The desizing furnace has a temperature of 500°C, a desizing time of 60 minutes, and a N2 protective atmosphere. The sintering furnace has a temperature of 800°C, a time of 60 minutes, and a N2 and H2 protective atmosphere.
[0063] Example 11 The method for preparing the capillary structure in this embodiment is as follows: A copper paste is prepared, wherein the copper powder is 35 wt% dendritic copper powder with a particle size of 10 μm, the pore-forming agent is 32 wt% ammonium chloride powder, the adhesive is 5% PMMA, and the solvent is 28% terpineol. The paste is thoroughly stirred to obtain a viscosity ≥30000 mPa•s. A screen with a pattern designed with a line width and spacing of 100 μm-100 μm is installed in a screen printing machine. The copper paste is printed onto the upper cover of the heat spreader using screen printing. The screen is then placed in an oven at 110°C for 30 minutes and completely dried in air. The upper cover of the heat spreader is then placed sequentially into a desizing furnace and a sintering furnace with a protective atmosphere. The desizing furnace has a temperature of 500°C, a desizing time of 60 minutes, and a N2 protective atmosphere. The sintering furnace has a temperature of 800°C, a time of 60 minutes, and a N2 and H2 protective atmosphere.
[0064] Comparative Example The method for preparing the capillary structure in this embodiment is as follows: Prepare copper paste, which is the same copper paste as in Example 1; install a screen with a pattern designed with a line width and line spacing of 1000μm-1000μm in a screen printing machine, and print the copper paste onto the upper cover of the heat spreader by screen printing. Then, place it in an oven at 110℃ for 30 minutes to dry completely in air atmosphere. Then, place the upper cover of the heat spreader into a desizing furnace and a sintering furnace with a protective atmosphere in sequence. The temperature of the desizing furnace is 500℃, the desizing time is 60 minutes, and the protective atmosphere is N2. The temperature of the sintering furnace is 800℃, the time is 60 minutes, and the protective atmosphere is N2 and H2 atmosphere.
[0065] Table 1 below shows the temperature difference test results for Examples 1 to 11 and the comparative examples: Table 1. Temperature difference test results of Examples 1 to 11 and comparative examples.
[0066] The comparison shows that the capillary structure of this embodiment can improve the heat transfer effect of the heat exchanger.
[0067] It should be noted that the various embodiments described above with reference to the accompanying drawings are merely illustrative of the present invention and not intended to limit its scope. Those skilled in the art should understand that any modifications or equivalent substitutions made to the present invention without departing from its spirit and scope should be included within the scope of the present invention. Furthermore, unless the context otherwise requires, words appearing in the singular include those in the plural, and vice versa. Additionally, unless specifically stated otherwise, all or part of any embodiment may be used in conjunction with all or part of any other embodiment.
Claims
1. A heat spreader, characterized in that, The heat spreader includes a plate body with an inner cavity and capillary structures formed on the inner side of the plate body; The capillary structure includes a plurality of capillary segments that are parallel to each other and equally spaced along a first direction; each capillary segment extends along a second direction, the width of the gap between two adjacent capillary segments is 10~500μm, and the width of each capillary segment along the first direction is the same and is 10~500μm; wherein, the first direction and the second direction are perpendicular to each other.
2. The temperature distribution plate as described in claim 1, characterized in that, The capillary structure is a three-dimensional interconnected pore structure with a pore size of less than or equal to 200 μm and a porosity of 40-80%.
3. The temperature distribution plate as described in claim 2, characterized in that, The pore size is 10~100μm.
4. The temperature distribution plate as described in claim 1, characterized in that, The plate includes an upper cover plate and a lower cover plate that is fixed to the upper cover plate and together with the upper cover plate forms the inner cavity; the capillary structure is formed on the side of the upper cover plate near the lower cover plate.
5. The temperature distribution plate as described in claim 4, characterized in that, The capillary structure extends at a height of 20~300μm along the upper cover plate toward the lower cover plate.
6. The temperature distribution plate as described in claim 5, characterized in that, The capillary structure extends at a height of 40~150μm along the upper cover plate toward the lower cover plate.
7. The temperature distribution plate as described in claim 4, characterized in that, The capillary structure is formed on the upper cover plate by screen printing; the line width and line spacing of the screen in the screen printing machine are both 10~500μm.
8. A method for preparing a heat spreader as described in any one of claims 4 to 7, characterized in that, The preparation method includes the following steps: The line width and line spacing of the screen are set according to the dimensions corresponding to the capillary structure. The screen is installed on a screen printing machine, and then copper paste is printed onto the top cover plate by screen printing. The copper paste printed onto the upper cover plate is sequentially dried, de-adhesive-removed, and sintered to obtain the capillary structure. The lower cover plate is fixed to the side of the upper cover plate where the capillary structure is located to obtain the temperature equalization plate.
9. The method for preparing a heat spreader as described in claim 8, characterized in that, The copper paste is made by mixing 10-80 wt% copper powder, 5-70 wt% pore-forming agent, 1-10 wt% adhesive and 5-40 wt% solvent.
10. The method for preparing a heat spreader as described in claim 9, characterized in that, The copper powder is any one of atomized copper powder, electrolytic copper powder, reduced copper powder, and plasma-processed copper powder; the shape of the copper powder is any one of dendritic, flake, and spherical; the particle size of the copper powder is 100nm~100μm, and the purity of the copper powder is greater than or equal to 98%.
11. The method for preparing a heat spreader as described in claim 9, characterized in that, The pore-forming agent is any one of organic solid small molecules, inorganic salts, copper salts, and copper oxides; the particle size of the pore-forming agent is in the micrometer range.
12. The method for preparing a heat spreader as described in claim 9, characterized in that, The adhesive is one or more of acrylic resins and epoxy resins.
13. The method for preparing a heat spreader as described in claim 9, characterized in that, The solvent is one or more of toluene, xylene, acetone, ethanol, and terpineol.
14. The method for preparing a heat spreader as described in claim 9, characterized in that, The viscosity of the copper paste is 10,000~100,000 mPa•s.
15. The method for preparing a heat spreader as described in claim 8, characterized in that, The drying is carried out in an oven at a temperature of 80~150℃ for 10~120 minutes; the glue removal is carried out in a glue removal furnace at a temperature of 300~650℃ with a first protective atmosphere for 10~120 minutes; the sintering is carried out in a sintering furnace at a temperature of 700~900℃ with a second protective atmosphere for 10~120 minutes; the first protective atmosphere and the second protective atmosphere are one or more of nitrogen, hydrogen and argon.