Capillary structure, uniform temperature plate, manufacturing method and application thereof

Abstract

The application discloses a capillary structure, a uniform temperature plate, a manufacturing method and application thereof. The manufacturing method comprises the following steps: providing a paste or slurry containing two or more metal powders and an organic binder, wherein one kind of metal powder is nano-nickel powder and / or micron-nickel powder; and performing sintering treatment on the paste or slurry, so that the two or more metal powders are combined with each other to form the capillary structure. The capillary structure has the advantages of low sintering temperature, less requirement for sintering atmosphere, large specific surface area and the like, is easy to manufacture, and is low in cost, and is especially suitable for manufacturing an ultrathin uniform temperature plate.

Description

Technical Field

[0001] This application specifically relates to a capillary structure, a heat spreader, its manufacturing method, and its application. Background Technology

[0002] Vapor chambers (VCs) are widely used in products such as mobile phones, laptops, tablets, LED heat dissipation, and semiconductor cooling chips due to their advantages such as low heat transfer start-up temperature, fast heat transfer speed, good temperature uniformity, high heat transfer power, low manufacturing cost, long life, and light weight. Most vapor chambers consist of a base plate, frame, and cover plate, forming a completely sealed vacuum flat-plate cavity. The cavity contains a cooling medium (water or refrigerant), and the inner wall has a capillary structure. Supporting columns within the cavity resist indentation caused by the vacuum negative pressure. The working principle of a vapor chamber is roughly as follows: when the vapor chamber comes into contact with a heat source, the bottom is heated, and the heat is transferred to the cooling medium through the capillary structure. Under negative pressure, the cooling medium evaporates rapidly, and the heated air rises and condenses back into liquid upon encountering the cold source above the vapor chamber. The condensed coolant then flows back to the bottom of the vapor chamber through the capillary structure. This process repeats, transferring heat away.

[0003] One known VC capillary structure is formed by sintering metal mesh and / or metal powder. To avoid oxidation of the metal powder during high-temperature sintering, a nitrogen-hydrogen mixed atmosphere with a hydrogen content of 1-10% (volume percentage) is typically used as the sintering atmosphere. Generally, the higher the sintering temperature, the more severe the oxidation phenomenon, requiring a higher proportion of hydrogen in the nitrogen-hydrogen mixed atmosphere, but this also brings greater safety hazards.

[0004] With the trend towards ultra-thin designs in mobile phones and other electronic products, the thickness of vapor chambers is decreasing, leading to a reduction in the thickness of the vapor chamber shell, capillary porous structure, support pillars, and vacuum chamber itself. For ultra-thin vapor chambers (VCs), simply using copper mesh to create capillary structures cannot meet the requirements for thickness and thermal conductivity. One improved solution is to make copper powder into a paste or slurry, using screen printing or extrusion to manufacture capillary structures of various shapes and thicknesses. However, on the one hand, pure copper powder requires a sintering temperature above 850℃ to achieve good sintering strength, and the addition of polymer binders can hinder the sintering process. On the other hand, the shell of ultra-thin VCs needs good strength, typically using copper alloys or copper-plated stainless steel. This requires a heat treatment temperature not exceeding 800℃. In other words, the sintering temperature for creating the capillary layer on the shell of ultra-thin VCs should be below 800℃. This is an irreconcilable contradiction and has long been a problem that the field has been eager to solve. Summary of the Invention

[0005] The main objective of this application is to provide a capillary structure, a heat spreader, its manufacturing method, and its application to overcome the shortcomings of the prior art.

[0006] To achieve the aforementioned objectives, the technical solution adopted in this application includes:

[0007] This application provides a method for fabricating a capillary structure, comprising:

[0008] Provide a paste or slurry containing at least a first metal powder and a second metal powder, wherein the second metal powder is nano-nickel powder and / or micron-nickel powder, and the first metal powder includes micron-sized metal powder composed of metal elements other than nickel;

[0009] The paste or slurry is sintered in a set atmosphere to allow at least a portion of the metal powder in the paste or slurry to bond together and form a capillary structure.

[0010] This application also provides capillary structures formed by any of the methods described in the foregoing embodiments.

[0011] This application also provides a capillary structure, which is mainly formed by combining multiple first metal powders and multiple second metal powders after sintering. The second metal powders are nano-nickel powders and / or micron-nickel powders, and the first metal powders include micron-sized metal powders composed of metal elements other than nickel.

[0012] This application embodiment also provides a method for manufacturing a heat spreader, including:

[0013] The first step is to create a capillary structure layer on the surface of the first substrate and / or the surface of the second substrate.

[0014] The second step involves sealing the first substrate and the second substrate together to form a vacuum chamber, and distributing the capillary structure layer within the vacuum chamber.

[0015] Furthermore, the first step includes:

[0016] The capillary structure layer is fabricated using any of the methods described in the foregoing embodiments.

[0017] This application also provides a heat spreader manufactured by any of the methods described in the foregoing embodiments.

[0018] This application embodiment also provides a temperature distribution plate, including...

[0019] A first substrate having a first surface;

[0020] A second substrate having a second surface, the second surface being disposed opposite to the first surface;

[0021] A capillary layer, at least covering a local area of ​​the first surface and / or a local area of ​​the second surface;

[0022] A vacuum cavity is formed by sealing the first substrate and the second substrate together. The capillary structure layer is disposed in the vacuum cavity, and a working medium is also distributed in the vacuum cavity.

[0023] The capillary layer has any of the capillary structures described in the foregoing embodiments.

[0024] This application also provides the use of any of the heat spreaders in the foregoing embodiments.

[0025] Compared to existing technologies, the technical solutions provided in the above embodiments of this application, by compounding micron-sized nickel powder and / or nano-sized nickel powder with micron-sized copper powder to form a paste or slurry, and then sintering it to form a capillary structure applicable as a heat spreader, not only significantly reduces the sintering temperature and the requirements for the sintering atmosphere, reducing energy consumption, but also greatly increases the heat transfer area of ​​the obtained capillary structure, which is conducive to increasing the rate at which the capillary structure absorbs the working medium, thereby facilitating the coolant recirculation of the heat spreader and effectively improving the heat transfer efficiency of the heat spreader. Furthermore, it can also mitigate the adverse effects on the heat spreader shell and other parts caused by sintering the capillary structure during the heat spreader manufacturing process. The aforementioned technical solutions provided in this application are suitable for manufacturing heat spreaders of various specifications, especially ultra-thin heat spreaders. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a typical process flow diagram of a heat spreader manufacturing process in this application;

[0028] Figure 2 This is an electron microscope image of the capillary structure sample obtained in Example 1.

[0029] Figure 3 This is an electron microscope image of the capillary structure sample obtained in Example 2. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0031] 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.

[0032] In the description herein, the terms “center,” “upper,” “lower,” “left,” “right,” “vertical,” “horizontal,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this document and for simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0033] In the description herein, the terms “first,” “second,” and “third” are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0034] In this description, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0035] In view of the aforementioned shortcomings of the prior art, the inventors of this case unexpectedly discovered during long-term research that when capillary structures are prepared by sintering a mixture of nano-nickel powder and / or micron-nickel powder with micron-copper powder, the sintering temperature is significantly lower than the melting point of either micron-nickel powder or micron-copper powder. Furthermore, the resulting capillary structure retains or even possesses better mechanical properties, while its specific surface area is significantly increased. Based on this unexpected discovery, the applicant has proposed the technical solution of this application, which will be described in detail below.

[0036] One aspect of this application provides a method for fabricating a capillary structure, comprising:

[0037] Provide a paste or slurry containing at least a first metal powder and a second metal powder, wherein the second metal powder is nano-nickel powder and / or micron-nickel powder, and the first metal powder includes micron-sized metal powder composed of metal elements other than nickel;

[0038] The paste or slurry is sintered in a set atmosphere to allow at least a portion of the metal powder in the paste or slurry to bond together and form a capillary structure.

[0039] Furthermore, the material of the first metal powder includes, but is not limited to, any one or more combinations of copper, aluminum, titanium, silver, and gold, preferably copper or a copper alloy.

[0040] In some embodiments, the paste or slurry can be sintered in an inert atmosphere, a weakly reducing atmosphere, or a reducing atmosphere at a temperature below the melting point of the first metal powder. The second metal powder can be nano-nickel powder and / or micron-nickel powder.

[0041] In some embodiments, the paste or slurry can be sintered in an inert atmosphere, a weakly reducing atmosphere, or a reducing atmosphere at a temperature lower than the melting point of the first metal powder but higher than the melting point of the second metal powder. The second metal powder can be nano-nickel powder.

[0042] In some embodiments, the paste or slurry can be sintered in an inert atmosphere, a weakly reducing atmosphere, or a reducing atmosphere at a temperature lower than the melting point of either the first metal powder or the second metal powder. The second metal powder can be micron-sized nickel powder.

[0043] In some embodiments, if nano-nickel powder and micron-sized copper powder are sintered, the nano-nickel powder, with its large specific surface area and higher activation energy, has its oxide layer reduced in a reducing atmosphere. Then, fresh metal atoms diffuse with the micron-sized copper powder, causing the nano-nickel powder and micron-sized copper powder to combine. During this process, the surface of the second metal powder may undergo micro-melting. This embodiment, in addition to its advantage of low sintering temperature, also benefits from the fact that some of the nano-nickel powder combines with the sintered body of the micron-sized copper powder during sintering and is exposed in the fluid channels within the capillary structure. Specifically, one or more regular or irregular nanoscale protrusions are formed on the inner wall of the fluid channels. This causes the flow pattern of the working medium within the fluid channels to be continuously or intermittently altered when the capillary structure is used as a heat spreader. The travel path within the fluid channels is significantly extended, the contact area is significantly increased, and the contact with the fluid channel walls is more thorough and comprehensive. This significantly improves the heat exchange efficiency between the working medium and the capillary structure, thereby significantly enhancing the heat transfer efficiency of the heat spreader.

[0044] In some embodiments, the manufacturing method further includes: before performing the sintering process, at least a portion of the second metal powder is attached to a portion of the surface of the first metal powder.

[0045] In some embodiments, the manufacturing method further includes:

[0046] A plurality of first metal powders are uniformly mixed with a plurality of second metal powders, such that at least a portion of the surface of the first metal powders is adhered to one or more second metal powders, thereby obtaining a pretreated metal powder;

[0047] The pretreated metal powder is uniformly mixed with an organic binder and / or solvent to form the paste or slurry.

[0048] In some preferred embodiments, the manufacturing method further includes:

[0049] After uniformly mixing multiple first metal powders and multiple second metal powders, the mixture is subjected to low-temperature heat treatment (200-500℃) to allow at least a portion of the surface of the first metal powders to adhere to one or more second metal powders, thereby obtaining a pretreated metal powder.

[0050] The pretreated metal powder is uniformly mixed with an organic binder and / or solvent to form the paste or slurry.

[0051] Such a low-temperature heat treatment in the early stage can make the copper powder and nickel powder uniform and prevent segregation, avoiding component segregation caused by the difference in particle size between nickel powder and copper powder during the process of making it into a paste, so that the nickel powder and copper powder in the paste are evenly distributed.

[0052] In some embodiments, at least a portion of the surface of the first metal powder is coated with a plurality of second metal powders.

[0053] In some embodiments, the manufacturing method further includes: degreasing the paste or slurry, followed by sintering.

[0054] Furthermore, considering that the metal powder film formed by printing from the slurry or paste contains organic matter such as resin binders, a degreasing treatment can be performed before high-temperature sintering. The degreasing treatment temperature is below 400°C, and the degreasing atmosphere is selected according to the decomposition requirements of the organic matter. For example, an oxidizing atmosphere, a vacuum atmosphere, an inert atmosphere, or a reducing atmosphere can be used.

[0055] In the above embodiments of this application, the sintering temperature can be lower than 800°C, which is significantly lower than the sintering temperatures of micron-sized copper powder and micron-sized nickel powder (the sintering temperature of micron-sized copper powder is at least 30-200°C lower than the melting point of copper metal, approximately 1080°C). Taking micron-sized copper powder as the first metal powder and nano-sized nickel powder as the second metal powder in a paste or slurry as an example, the sintering temperature can be reduced to 350-600°C, while maintaining good strength. For pastes or slurries containing other materials as the first metal powder and micron-sized nickel powder and / or nano-sized nickel powder, the sintering temperature is also significantly lower than that of the first metal powder. In particular, the reduction in sintering temperature is especially pronounced for schemes using nano-sized nickel powder, an effect likely caused by the addition of nano-sized nickel powder. Furthermore, the sintering time can also be shortened. For example, in the above embodiments of this application, the sintering time can be adjusted according to the sintering temperature. Typically, the sintering time (including the degreasing process of organic matter) can be controlled between 30 min and 24 h. The sintering atmosphere can be an inert atmosphere, a weak reducing atmosphere (low hydrogen atmosphere, such as a hydrogen ratio of less than 12.5 V / V% or a carbon monoxide ratio of less than 12.5 V / V%), a reducing atmosphere (atmospheres of hydrogen, carbon monoxide, ammonia decomposition, etc.), or a vacuum atmosphere.

[0056] Another aspect of the embodiments of this application provides a capillary structure formed by any of the methods in the foregoing embodiments.

[0057] Another aspect of the embodiments of this application provides a capillary structure, which is mainly formed by combining multiple first metal powders and multiple second metal powders after sintering. The second metal powders are nano-nickel powders and / or micron-nickel powders, and the first metal powders include micron-sized metal powders composed of metal elements other than nickel.

[0058] In some embodiments, the mass ratio of the first metal powder to the second metal powder used to form the capillary structure is 50-90:1-15.

[0059] Another aspect of this application provides a method for manufacturing a heat spreader, comprising:

[0060] The first step is to create a capillary structure layer on the surface of the first substrate and / or the surface of the second substrate.

[0061] The second step involves sealing the first substrate and the second substrate together to form a vacuum chamber, and distributing the capillary structure layer within the vacuum chamber.

[0062] Furthermore, the first step includes:

[0063] The capillary structure layer is fabricated using any of the methods described in the foregoing embodiments.

[0064] In some embodiments, the first step includes: applying a paste or slurry to the surface of a first substrate and / or a second substrate, followed by the fabrication of the capillary layer.

[0065] In some embodiments, the first step includes: screen printing a paste or slurry onto the surface of a first substrate and / or a second substrate.

[0066] In some embodiments, the first step further includes: fabricating at least one support within the heat exchanger using any of the methods described in the foregoing embodiments.

[0067] Another aspect of this application provides a vapor chamber manufactured by any of the methods described in the foregoing embodiments.

[0068] In some embodiments, the method for manufacturing the heat spreader specifically includes:

[0069] The capillary structure layer is fabricated using any of the methods described in the above embodiments, wherein the capillary structure layer at least covers a local area of ​​one side surface of the first substrate;

[0070] A support is formed by printing and sintering a paste or slurry. The support is disposed between a first substrate and a second substrate to counteract the force that causes the first substrate and the second substrate to move toward each other.

[0071] A vacuum chamber is formed by sealing between the first substrate and the second substrate, and the capillary layer and the support are both distributed within the vacuum chamber.

[0072] In some embodiments, the method for manufacturing the heat spreader includes:

[0073] A capillary structure layer and a support are formed by using any of the methods in the above embodiments. The capillary structure layer covers at least a local area of ​​one side surface of the first substrate, and the support is disposed between the first substrate and the second substrate to counteract the force that causes the first substrate and the second substrate to move toward each other.

[0074] A vacuum chamber is formed by sealing between the first substrate and the second substrate, and the capillary layer and the support are both distributed within the vacuum chamber.

[0075] In the above embodiments of this application, the manufacturing method may further include other operations, such as welding the heat spreader, injecting water (or other working media), and vacuuming. These operations can all be performed in a manner known in the art. For example, the heat spreader can be welded using a local laser welding machine.

[0076] In the above embodiments of the present invention, by simultaneously adding nano-nickel powder and / or micron-nickel powder and other micron-sized metal powders such as micron-sized copper powder to the slurry or paste, when the capillary structure layer and support (especially the former) are made with the slurry or paste, not only can the low sintering temperature and short sintering time be achieved as mentioned above, and a capillary structure with excellent heat transfer performance be obtained, but the problem of adverse effects on the performance of the heat spreader shell material caused by the high-temperature sintering required for the existing capillary structure layer is also avoided. Specifically, generally speaking, the outer shell material of the heat spreader is hardened copper or copper alloy to ensure that the heat spreader has good strength. However, the hardness of copper alloy will decrease during high-temperature heat treatment. This application significantly reduces the sintering temperature of the capillary structure (for example, for capillary structures made of copper alloy, the sintering temperature can be lower than 800℃, which is of great significance for maintaining the hardness of the outer shell material of the heat spreader). Moreover, after adding nickel powder and sintering, the water absorption rate of the capillary structure increases. The reason may be that there is a copper-nickel alloy layer on the surface of the copper powder. This copper-nickel alloy layer has higher hydrophilicity, which leads to the increase in the water absorption rate of the capillary structure.

[0077] Another aspect of this application provides a temperature distribution plate, including...

[0078] A first substrate having a first surface;

[0079] A second substrate having a second surface, the second surface being disposed opposite to the first surface;

[0080] A capillary layer, at least covering a local area of ​​the first surface and / or a local area of ​​the second surface;

[0081] A vacuum cavity is formed by sealing the first substrate and the second substrate together. The capillary structure layer is disposed in the vacuum cavity, and a working medium is also distributed in the vacuum cavity.

[0082] Furthermore, the capillary layer has any of the capillary structures described in the foregoing embodiments.

[0083] In some embodiments, the heat exchange plate is an ultra-thin heat exchange plate.

[0084] In some embodiments, at least one support within the heat spreader also has any of the capillary structures described in the foregoing embodiments.

[0085] In some embodiments, the heat spreader includes:

[0086] A first substrate having a first surface;

[0087] A second substrate having a second surface, the second surface being disposed opposite to the first surface;

[0088] A capillary layer, at least covering a local area of ​​the first surface and / or a local area of ​​the second surface;

[0089] A support body is disposed between the first substrate and the second substrate to counteract the force that causes the first substrate and the second substrate to move toward each other;

[0090] A vacuum cavity is formed by sealing the first substrate and the second substrate together. The capillary layer and the support are both disposed in the vacuum cavity, and a working medium is also distributed in the vacuum cavity.

[0091] In some embodiments, the capillary layer is formed on the second surface, and the support is formed on the first surface with its tip abutting against the capillary layer; or, the capillary layer is formed on the first surface, and the support is formed on the second surface with its tip abutting against the capillary layer.

[0092] In some embodiments, the capillary layer is formed on the second surface, and the support is formed on the capillary layer with its top end abutting against the first surface.

[0093] In addition, the heat spreader may also include other components, such as frames, sealants or seals required to seal the first substrate and the second substrate to form a vacuum chamber, as well as other accessories, which are well known in the art and will not be described in detail here.

[0094] In the above embodiments of this application, the applicable printing method can be selected from, but is not limited to, stencil printing, gravure printing, etc. For example, screen printing technology can be used. Furthermore, in some embodiments, the support body can be considered to be manufactured using paste screen printing technology. By employing a printing method, compared to other existing methods, it is very convenient to produce capillary layers and supports of various shapes and sizes. The operation is simple, low-cost, safe, environmentally friendly, and precisely controllable. It is particularly suitable for preparing capillary layers and supports with ultra-thin thickness and good mechanical strength, thereby facilitating the realization of ultra-thin heat exchange plates and improving the performance of the heat exchange plates.

[0095] In the above embodiments of this application, the capillary layer and the support can be formed after a single printing and sintering process, or after multiple printing and sintering processes. For example, the printing operation can be repeated, followed by sintering, or the printing and sintering operations can be performed alternately. During the printing process, by adjusting the specifications of the printing plate, such as the cell depth, length, and width of the gravure printing plate, or the height and width of the screen wall, or the mesh size of the screen, and by adjusting the number of printing cycles, the height (which in some cases can also be considered as its thickness), length, and width of the capillary layer and the support can be conveniently and precisely controlled, so that they can be well matched with other components in the heat spreader, such as the first substrate or the second substrate, thereby giving the heat spreader a more ideal performance.

[0096] In the above embodiments of this application, the thickness of the capillary layer in the ultrathin heat spreader can be 1-3 times the particle size of the first metal powder. For example, if the thickness of the capillary layer is 70 μm, the preferred particle size of the first metal powder is 20-70 μm, and more preferably 30-55 μm.

[0097] Furthermore, the mesh diameter of the screen printing plate should be larger than the particle size of the metal powder (especially the first metal powder). Generally, during screen printing, the paste is scraped across the screen printing plate once, forming a layer of metal powder on the first or second substrate. Therefore, multiple applications can be made depending on the required thickness. Simultaneously, spherical metal powder is preferred for optimal screen printing, as it easily passes through the mesh and adheres to the first or second substrate during application. When the metal powder is irregularly shaped, the mesh diameter of the screen printing plate must be much larger than the powder particle size; otherwise, the irregular metal powder will easily get caught on the screen printing plate's wire mesh.

[0098] For example, the shape and height of the support can be selected according to actual needs, such as stripes, crosses, crisscrosses, circles, rings, etc. The height of the support can be adjusted through the screen printing process. The aperture of the screen printing plate can be selected as needed. The printing plate used may also not contain mesh, but simply be a printing plate of different shapes. The support can be screen printed on the inner wall of the heat spreader or on the capillary layer of the heat spreader.

[0099] In the above embodiments of this application, the capillary layer and the support can be fabricated simultaneously. For example, the same printing plate can be used, along with the aforementioned first slurry or paste and second slurry or paste, to print the preforms of the capillary layer and the support in one step, and then sinter to form the capillary layer.

[0100] In the above embodiments of this application, the capillary layer and the support can also be fabricated in steps. For example, a slurry or paste can be printed and sintered to form a capillary layer using any of the methods described in the foregoing embodiments, and then another slurry or paste can be printed and sintered on the capillary layer using any of the methods described in the foregoing embodiments to form the support. Alternatively, referring to any of the methods described in the above embodiments, a preform of the capillary layer can be printed using a slurry or paste, and then a preform of the support can be printed on the capillary layer using another slurry or paste, followed by sintering to form the capillary layer and the support.

[0101] Furthermore, the capillary layer and the support can be independent of each other or integrally formed.

[0102] In the above embodiments of this application, by sintering after printing, the resulting capillary layer and support, especially the latter, can have good strength. The process conditions required for sintering can be adjusted according to actual needs.

[0103] In the above embodiments of this application, the support body can be one or more, and its shape can be various, such as columnar, frustum-shaped, conical, strip-shaped, cross-shaped, intersecting, circular, ring-shaped, or other irregular shapes. Preferably, the support body is a support column, which can be two or more, and these support columns can be arranged at equal or unequal intervals. Through the aforementioned support body, a strong support can be formed between the first substrate and the second substrate, giving the heat spreader better strength and ensuring that the heat spreader will not easily deform during the use of the product. When multiple support columns are equally spaced, the external force on the heat spreader can be balanced, preventing the heat spreader from deforming. In some other more specific embodiments, the support body can also be strip-shaped, ring-shaped, cross-shaped, etc., which is not specifically limited.

[0104] In the above embodiments of this application, the capillary layer can be a continuously extending structure, or it can be composed of multiple independent capillary layers, or one or more windows can be opened on the continuous capillary layer.

[0105] In the above embodiments of this application, the shape and size (including its thickness, length, width, etc.) of the capillary layer can be determined according to actual needs and can be set to match the shape and size of the vacuum chamber. For example, the capillary layer can be regular or irregular in shape.

[0106] In the above embodiments of this application, the first substrate and the second substrate can be made of metal or non-metal materials, such as high thermal conductivity ceramic materials, and are preferably made of metal materials.

[0107] In the above embodiments of this application, the vacuum chamber is a space where the heat spreader dissipates and heat is uniformly distributed, and it can be constructed in a manner known in the art. For example, after the capillary layer and the support are fabricated, the first substrate and the second substrate are sealed together to form one or more hollow chambers. Then, a working medium is filled into the hollow chamber, which can be a liquid with a boiling point below a preset value, such as alcohol, alcohol solution, or water. The hollow chamber is then evacuated to a vacuum, near-vacuum, or semi-vacuum state, and finally sealed to form the vacuum chamber.

[0108] During the aforementioned vacuuming process, the presence of the support structure causes the first and second substrates to deform under negative pressure. Clearly, the support structure also prevents the heat exchange plate from deforming and being damaged under external pressure.

[0109] Furthermore, the aforementioned vacuum cavity can be a single cavity on a unit of metal material, or it can be two or more cavities on a single unit of metal material. The inner surface, side surface, and outer surface of the cavity can be flat, or it can have a design with several column-like protrusions, holes, or grooves on the surface.

[0110] Furthermore, after the heat source in conjunction with the heat spreader generates heat, the working medium in the vacuum chamber absorbs heat and evaporates to generate steam. When the steam comes into contact with the first or second substrate, it cools into a liquid. At the same time, the capillary structure layer can generate capillary forces to promote the return of the cooled liquid, thereby achieving the heat absorption performance and uniform heat performance of the heat spreader, which together form an efficient heat transfer path.

[0111] In the above embodiments of this application, the slurry or paste may contain metal powder (including first metal powder and second metal powder), organic binder and / or solvent, etc. It may further include a dispersion medium and optional additives.

[0112] In some embodiments, the shapes of the first and second metal powders are not particularly limited; spherical, near-spherical, or irregular shapes can all be used appropriately. However, spherical metal powders are more suitable for methods such as screen printing.

[0113] In some embodiments, the first and second metal powders can be manufactured by atomization, electrolysis, reduction, chemical methods, melt rotation, and other extreme cold solidification methods, and are not limited thereto. For example, in industry, water atomization is preferred, i.e., irregular metal powder is obtained by impacting molten copper with high-pressure water.

[0114] In some implementations, the first and second metal powders can also be obtained through commercial purchases or other means.

[0115] In some embodiments, the dispersion medium may be water, an organic solvent, an organic resin, or any combination thereof, and may also be obtained through commercial purchases.

[0116] In some embodiments, the organic binder is an organic resin, which serves as both a dispersant and a binder. Substances that can be used as resin binders include epoxy resins, phenolic resins, polyacrylaldehyde, polyester resins, acrylic resins, acrylonitrile resins, paraffin wax, vinyl alcohol resins, polyolefin resins, polyethylene resins, vinyl acetate resins, etc., or natural resins such as paraffin wax, beeswax, tar, rosin, and gum, but are not limited to these.

[0117] Obviously, the aforementioned dispersion medium, additives, etc., should be able to volatilize during heating, especially at the aforementioned sintering temperature, and should not leave any residue after the metal is sintered.

[0118] The aforementioned adjuvants may be of types well known in the art, and will not be described in detail here.

[0119] For example, a conventional amount of defoamer can be added to the slurry or paste. Suitable defoamers include, but are not limited to, polyether-modified silicone defoamers, polysiloxane defoamers, polyether defoamers, etc.

[0120] For example, a conventional amount of pore-forming agent can be added to the slurry or paste. This pore-forming agent volatilizes during high-temperature sintering, leaving voids and increasing porosity. However, the addition of the pore-forming agent can hinder the sintering of the metal powder. For example, copper powder requires higher sintering temperatures and times to sinter itself, and may sinter together with other components of the heat spreader. The particle size of the pore-forming agent is generally chosen to be slightly smaller than that of the metal powder.

[0121] In some implementations, the aforementioned organic resins and other polymeric materials can be thoroughly mixed with the metal powder to ensure uniform dispersion of the metal powder. Solvents can be added as needed, and the mixture can be heated during the mixing process to ensure homogeneous mixing and ultimately form the desired slurry or paste. It is crucial that no metal powder precipitation or stratification between the polymeric materials and the metal powder occurs.

[0122] In some implementations, the slurry or paste can be made to have suitable fluidity, viscosity, etc. by adjusting the type and content of the dispersion medium and / or additives in the slurry or paste, thereby meeting the needs of printing different supports. For example, the viscosity of the slurry or paste can be controlled to 8000Pa-50000Pa, preferably 15000Pa-30000Pa.

[0123] In some embodiments, the paste or slurry comprises 50 wt% to 90 wt% of a first metal powder and 1 wt% to 15 wt% of a second metal powder.

[0124] Furthermore, since nickel powder is magnetic, its magnetism is eliminated when the nickel content is low (e.g., the nickel content in the paste or slurry is below 10 wt%), after alloying with copper powder during high-temperature sintering. If a heat spreader containing the capillary structure formed by this paste or slurry is used in electronic products such as mobile phones that receive signals, it is especially necessary to eliminate nickel powder segregation to prevent the capillary structure from becoming magnetic.

[0125] In some embodiments, the particle size of the first metal powder is 10-100 μm, preferably 10-50 μm.

[0126] In some embodiments, the loose powder density of the first metal powder is 0.7-5 g / cm³. 3 The preferred concentration is 1.5-5.5 g / cm³. 3 .

[0127] In some embodiments, the particle size of the second metal powder is 200nm-50μm, preferably 500nm-10μm.

[0128] Another aspect of this application provides the use of any of the vapor chambers in the foregoing embodiments in the manufacture of electronic devices, optoelectronic devices, or semiconductor devices.

[0129] For example, this application provides an electronic product that includes any of the heat spreaders described in the foregoing embodiments. Typical electronic products include mobile phones, laptops, tablets, etc., but are not limited to these.

[0130] For example, embodiments of this application provide a type of lighting or light source device, such as an LED light source, whose heat dissipation structure includes any of the heat spreaders in the foregoing embodiments.

[0131] For example, embodiments of this application provide a type of semiconductor device that may include a heat dissipation structure for the hot end of a semiconductor cooling wafer, and the heat dissipation structure includes any of the heat spreaders in the foregoing embodiments.

[0132] The technical solution of this application will be explained in more detail below with reference to several embodiments and accompanying drawings.

[0133] Examples 1-4 These examples involve a method for preparing a class of capillary structures, including:

[0134] A series of pastes are provided, comprising micronized copper powder (a), micronized nickel powder or nano-nickel powder (b), and an organic binder (c) produced by Suzhou Tongbaorui New Materials Co., Ltd. The organic binder is made of acrylic resin. The specific compositions of these pastes are shown in Table 1.

[0135] These pastes were coated onto copper foil to form coatings with a thickness of 70 μm and a length of 80 mm. They were then sintered under the conditions shown in Table 2 to obtain a series of capillary structures. The microstructures of the capillary samples obtained in Examples 1 and 2 are shown below. Figure 2 , Figure 3 As shown.

[0136] Comparative Example 1: This comparative example relates to a method for preparing a capillary structure, which includes:

[0137] A paste is provided, comprising 75 wt% copper powder (particle size 45 μm), 5 wt% tin powder (particle size 10 μm), and 20 wt% acrylic resin. Both the copper and tin powders are produced by Suzhou Tongbaorui New Materials Co., Ltd.

[0138] The paste was applied to a copper foil to form a coating with a thickness of 70 μm and a length of 80 mm. Then, it was sintered under the conditions shown in Table 2 to obtain a capillary structure.

[0139] Comparative Example 2: This comparative example involves a method for preparing a capillary structure, which includes:

[0140] A paste is provided comprising 75 wt% copper powder (particle size 45 μm) and 25 wt% acrylic resin. The copper powder is produced by Suzhou Tongbaorui New Materials Co., Ltd.

[0141] The paste was applied to a copper foil to form a coating with a thickness of 70 μm and a length of 80 mm. Then, it was sintered under the conditions shown in Table 2 to obtain a capillary structure.

[0142] The water absorption rate of the capillary structures prepared in Examples 1-4 and Comparative Examples 1-2 was tested. The test was conducted using a vertical water absorption method, and the time it took for water to be absorbed from the bottom to the top of the capillary structure was recorded. The test results are also shown in Table 2.

[0143] Table 1

[0144]

[0145] Table 2

[0146] 1 400℃, 30min 750℃, 30min 5% hydrogen good 80s 2 400℃, 30min 750℃, 30min 5% hydrogen good 78s 3 400℃, 30min 750℃, 30min 5% hydrogen good 180s 4 400℃, 30min 750℃, 30min 5% hydrogen good 83s Comparative Example 1 400℃, 30min 750℃, 30min 5% hydrogen Difference Comparative Example 2 400℃, 30min 850℃, 30min 5% hydrogen generally 145

[0147] Examples 5-8: The preparation method of the capillary structure involved in these examples is basically the same as that in Examples 1-4, except that:

[0148] (1) The composition of the series of ointments provided is shown in Table 3.

[0149] (2) The sintering conditions used are shown in Table 4.

[0150] Table 3

[0151]

[0152] Table 4

[0153] 5 400℃, 30min 800℃, 30min 5% hydrogen 6 400℃, 30min 800℃, 30min 5% hydrogen 7 400℃, 30min 700℃, 30min 5% hydrogen 8 400℃, 30min 750℃, 30min 5% hydrogen

[0154] Application example: See Figure 1 As shown, a method for manufacturing a heat spreader may include the following steps:

[0155] (1) Provide a first substrate 11 and a second substrate 12;

[0156] (2) A paste containing metal powder is printed on the first surface 110 of the first substrate 11, and then degreased and sintered in a vacuum environment to form a capillary layer 13.

[0157] (3) Using other existing methods, such as casting, welding, etching, etc., multiple support pillars 14 are formed on the second surface 120 of the second substrate 12;

[0158] (4) The first surface of the first substrate and the second surface of the second substrate are positioned opposite each other, and the top of each support column abuts against the capillary structure layer.

[0159] (5) A hollow cavity is formed by sealing between the first substrate and the second substrate, so that the capillary structure layer and each support column are located in the hollow cavity. Then, the working medium 15 such as water, ethanol or acetone is filled in the hollow cavity. After that, the hollow cavity is evacuated and finally sealed to form a vacuum chamber.

[0160] The operations of steps (1) and (3)-(5) above can be performed in accordance with the known methods in this field.

[0161] The capillary layer 13 described in step (2) was prepared according to Examples 1-4 and Comparative Example 2. A series of vapor chamber samples with identical dimensions and structures were thus produced (samples 1-4 each had the capillary structure of Examples 1-4, and sample 5 had the capillary structure of Comparative Example 2). The first substrate 11 and the second substrate 12 were both made from copper plates with a thickness of 0.08 mm, processed through cutting and sheet metal work. The thickness of the capillary layer was 0.1 mm, the height of the support columns was 0.1 mm, the diameter was 0.15 mm, the spacing between the support columns was 0.3 mm, and the volume ratio of injected water to the capillary layer was 1.2:1. Performance tests were conducted on these samples, and the results showed that the specific surface area and thermal conductivity of the capillary layer in Examples 1-4 were significantly better than those in Comparative Examples 1 and 2. The products in Examples 5-8 also showed similar performance.

[0162] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for fabricating a capillary structure, characterized in that, include: After uniformly mixing multiple first metal powders and multiple second metal powders, the mixture is subjected to low-temperature heat treatment at 200~500℃, so that at least a portion of the surface of the first metal powders is adhered to one or more second metal powders, thereby obtaining a pretreated metal powder. The pretreated metal powder is uniformly mixed with an organic binder to form a paste or slurry with a viscosity of 8000 Pa·s to 50000 Pa·s. The paste or slurry includes a first metal powder, a second metal powder, and an organic binder. The content of the first metal powder is >70 wt% and ≤90 wt%, and the content of the second metal powder is 1 wt% to 15 wt%. The first metal powder includes micron-sized metal powder composed of any one or more of copper, aluminum, titanium, silver, and gold. The particle size of the first metal powder is larger than that of the second metal powder. The particle size of the first metal powder is 10 to 100 μm. The second metal powder is made of nickel and has a particle size of 200 nm to 50 μm. The paste or slurry is subjected to degreasing and sintering treatments in an inert atmosphere, a weak reducing atmosphere, a reducing atmosphere, or a vacuum atmosphere, so that at least some of the metal powders in the paste or slurry are combined to form a capillary structure, wherein the sintering temperature is ≥700℃ and <800℃.

2. The manufacturing method according to claim 1, characterized in that: The first metal powder is made of copper or a copper alloy.

3. The manufacturing method according to claim 1, characterized in that: At least a portion of the surface of the first metal powder is coated with multiple second metal powders.

4. The manufacturing method according to claim 1, characterized in that: The organic adhesive includes resin adhesives.

5. The manufacturing method according to claim 1, characterized in that: The loose powder density of the first metal powder is 0.7~5 g / cm³. 3 .

6. The manufacturing method according to claim 1, characterized in that: The first metal powder has a particle size of 10~50μm and a loose powder density of 1.5~5.5g / cm³. 3 .

7. A method for manufacturing a heat spreader, comprising: The first step is to create a capillary structure layer on the surface of the first substrate and / or the surface of the second substrate. The second step involves sealing the first substrate and the second substrate together to form a vacuum chamber, and distributing the capillary structure layer within the vacuum chamber. The first step is characterized by comprising: The capillary structure layer is fabricated using the method described in any one of claims 1-6.

8. The manufacturing method according to claim 7, characterized in that, The first step includes: applying a paste or slurry to the surface of a first substrate and / or a second substrate, followed by the fabrication of the capillary layer.

9. The manufacturing method according to claim 8, characterized in that, The first step includes: applying a paste or slurry to the surface of a first substrate and / or a second substrate by extrusion.

10. The manufacturing method according to claim 8, characterized in that, The first step includes: printing paste or slurry onto the surface of a first substrate and / or a second substrate using screen printing.

11. The manufacturing method according to claim 7, characterized in that, The first step further includes: manufacturing at least one support within the heat exchange plate using the method described in any one of claims 1-6.

12. The manufacturing method according to claim 7, characterized in that: The heat exchange plate is an ultra-thin heat exchange plate.

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