Electronic devices, heat spreaders, and methods for preparing heat spreaders

Abstract

This invention relates to the field of electronic product technology, specifically disclosing an electronic device, a vapor chamber, and a method for preparing the vapor chamber. The method for preparing the vapor chamber includes the following steps: preparing a first cover plate and a second cover plate; forming a connecting layer on the outer contour edges of the first and second cover plates, wherein the melting point of the connecting layer is lower than the melting points of the first and second cover plates; and welding and fixing the connecting layer on the first cover plate and the connecting layer on the second cover plate together using diffusion welding to form a sealed cavity between the first and second cover plates. The vapor chamber and its preparation method of this invention can improve the production efficiency and reduce the production cost of vapor chambers.

Description

Technical Field

[0001] This invention relates to the field of electronic product technology, and in particular to an electronic device, a heat spreader, and a method for preparing the heat spreader. Background Technology

[0002] Currently, VC (Vapor Chamber) heat sinks are widely used in terminal electronic products such as mobile phones, tablets, and laptops. Terminal electronic products are characterized by their thinness, lightness, and portability. In particular, 5G is the future development trend of the consumer electronics field. While the computing power of chips has been significantly improved, their power consumption is also much higher than that of 4G chips. Therefore, the demand for thin and light heat sinks in consumer electronics products will become increasingly strong in the future.

[0003] The upper and lower cover plates of the heat spreader often employ diffusion welding for sealing. This addresses issues such as air leakage and dead temperature (where air leakage prevents the temperature at the weld point from rising) and poor performance caused by capillary contamination during the previous brazing process. It also overcomes application defects such as surface dents and insufficient strength. Diffusion welding technology can ensure consistent quality during mass production. However, achieving a diffusion weld surface requires long production times and extremely high temperatures, resulting in low production efficiency and high costs. Summary of the Invention

[0004] This invention discloses an electronic device, a heat spreader, and a method for preparing the heat spreader, in order to solve the problems of low production efficiency and high cost of heat spreaders in the prior art.

[0005] To achieve the above objectives, embodiments of the present invention disclose a method for preparing a heat spreader, comprising the following steps:

[0006] Prepare the first cover plate and the second cover plate;

[0007] A connecting layer is formed at the outer contour edges of the first cover plate and the second cover plate, the melting point of the connecting layer being lower than the melting points of the first cover plate and the second cover plate; and

[0008] Diffusion welding is used to weld and fix the connecting layer on the first cover plate and the connecting layer on the second cover plate into one piece so that the first cover plate and the second cover plate form a sealed cavity.

[0009] In the process of preparing the heat spreader, the present invention first performs tin melting treatment on the outer edge contours of the first and second cover plates of the heat spreader to form a connecting layer. The melting point of the connecting layer is much lower than that of copper. Therefore, the temperature requirement is not as high during subsequent diffusion soldering, and the melting time at the solder joint is relatively short. This can improve the production efficiency of the heat spreader and reduce its production cost.

[0010] As an optional implementation, in an embodiment of the present invention, the steps of preparing the first cover plate and the second cover plate include:

[0011] The first cover plate and the second cover plate are formed by processing copper plates;

[0012] The first cover plate and the second cover plate are pickled; and

[0013] Micro-etching is performed on the first cover plate and the second cover plate.

[0014] In this step, copper is used to fabricate the first and second cover plates, ensuring the heat dissipation effect of the final heat spreader. Furthermore, after acid etching and micro-etching of the first and second cover plates, smooth and flat surfaces are obtained, providing a better foundation for subsequent steps.

[0015] As an optional implementation, in an embodiment of the present invention, during the pickling process of the first cover plate and the second cover plate, a hydrochloric acid solution with a concentration of 5% to 7% is used to pickle the first cover plate and the second cover plate. This can remove grease and organic matter from the surfaces of the first cover plate and the second cover plate, and can also prevent the first cover plate and the second cover plate made of copper from being corroded by excessively high concentrations of hydrochloric acid solution; and / or,

[0016] During the micro-etching process of the first cover plate and the second cover plate, a sodium persulfate solution with a concentration of 2% to 5% is used to micro-etch the first cover plate and the second cover plate. On the one hand, this makes the surfaces of the first cover plate and the second cover plate smoother and flatter, providing a more reliable foundation for the preparation of the bonding layer. On the other hand, it can also prevent the first cover plate and the second cover plate made of copper from being severely corroded by the excessive concentration of sodium persulfate solution.

[0017] As an optional implementation, in an embodiment of the present invention, the step of forming a connecting layer on the outer contour edges of the first cover plate and the second cover plate includes: treating the first cover plate and the second cover plate with a tin-plating solution to form the connecting layer on the outer contour edges of the first cover plate and the second cover plate. In this invention, a layer of tin is deposited on the first cover plate and the second cover plate using a tin-plating solution to form the connecting layer. This connecting layer is a tin-plating layer, resulting in smooth, flat, and dense surfaces on the first and second cover plates. Furthermore, the first and second cover plates are less prone to bursting or punctures, ensuring the structural strength and stability of the first and second cover plates.

[0018] As an optional implementation, in an embodiment of the present invention, the step of performing tinning treatment on the first cover plate and the second cover plate using a tinning solution to form the connecting layer at the outer contour edges of the first cover plate and the second cover plate includes:

[0019] The first cover plate and the second cover plate are pre-impregnated with a first tin oxide solution; and

[0020] The first cover plate and the second cover plate were immersed in a second tin oxide solution;

[0021] The tin content in the first tin-ion solution is less than the tin content in the second tin-ion solution.

[0022] In other words, during the process of forming the bonding layer on the first and second cover plates, the first and second cover plates are first pre-immersed in a first tin-melting solution with a low tin content. This allows for a slow tin-melting process, improving tin whisker defects. Then, a second tin-melting solution with a higher tin content is used for immersion. This process ensures the density and surface flatness of the tin-melting layer on the first and second cover plates, thereby improving the structural strength of the final heat spreader and the ease of diffusion soldering.

[0023] As an optional implementation, in an embodiment of the present invention, the thickness of the bonding layer is 0.5 μm to 2.0 μm in the direction perpendicular to the surface of the bonding layer, providing the necessary thickness basis for subsequent diffusion bonding.

[0024] As an optional implementation, in an embodiment of the present invention, the connecting layer includes a Cu3Sn layer, a Cu6Sn5 layer, and a Sn layer stacked sequentially. The Cu3Sn layer is disposed in contact with the surface corresponding to the first cover plate and the surface corresponding to the second cover plate. That is to say, in the direction away from the surfaces of the first and second cover plates, the Sn content gradually increases and the copper content gradually decreases, eventually forming a Sn surface layer, which facilitates the reduction of the melting temperature during the diffusion welding process.

[0025] As an optional implementation, in embodiments of the present invention, the thickness of the Cu3Sn layer is 0.05 μm to 0.15 μm in the direction perpendicular to the connecting layer; and / or,

[0026] The thickness of the Cu6Sn5 layer is 0.25 μm to 0.35 μm; and / or,

[0027] The thickness of the Sn layer is 0.5 μm to 0.7 μm.

[0028] In this invention, the Sn content in the connecting layer gradually increases in the direction away from the surfaces of the first and second cover plates, and the thickness of the Sn layer is greater than that of the Cu3Sn layer and Cu6Sn5 layer, which facilitates diffusion welding.

[0029] On the other hand, this invention also discloses a heat spreader, which is prepared using the above-described heat spreader preparation method. The heat spreader includes a first cover plate and a second cover plate, which together form a sealed cavity. A connecting layer is provided on the outer edge contours of both the first and second cover plates, and the connecting layers of the first and second cover plates are connected by diffusion soldering. Because the outer edge contours of the first and second cover plates in this invention have a connecting layer, which is a tin-plated layer, and the outer surface of this tin-plated layer is tin, the melting point of which (231.89℃) is much lower than that of copper (1083.4℃), the temperature requirement during subsequent diffusion soldering is not as high. Furthermore, the copper base does not melt when the tin melts, thus maintaining the copper base structure well. The melting time at the solder joint is also relatively short, which improves the production efficiency of the heat spreader and reduces its production cost.

[0030] In another aspect, embodiments of the present invention also disclose an electronic device, which includes the aforementioned heat spreader.

[0031] Compared with the prior art, the electronic device, the heat spreader, and the method for preparing the heat spreader of the present invention have at least the following beneficial effects:

[0032] In the process of preparing the heat spreader, a bonding layer is first formed by tinning on the outer edge contours of the first and second cover plates of the heat spreader. The melting point of this bonding layer is much lower than that of copper. Therefore, the temperature requirement is not as high during subsequent diffusion soldering, and the melting time at the solder joint is relatively short. This can improve the production efficiency of the heat spreader and reduce its production cost. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 is a cross-sectional view of the heat spreader disclosed in an embodiment of the present invention;

[0035] Figure 2 This is a three-dimensional structural schematic diagram of the heat spreader disclosed in an embodiment of the present invention;

[0036] Figure 3 This is a cross-sectional view of the edge contour of the heat spreader disclosed in the embodiments of the present invention;

[0037] Figure 4 This is a flowchart of the preparation method of the heat spreader disclosed in the embodiments of the present invention;

[0038] Figure 5 This is a flowchart of the steps for preparing the first cover plate and the second cover plate in the preparation method disclosed in the embodiments of the present invention;

[0039] Figure 6 This is a flowchart of the preparation method for forming the connecting layer disclosed in the embodiments of the present invention.

[0040] Icons: 10, First cover plate; 20, Second cover plate; 30, Connecting layer; 31, Cu3Sn layer; 32, Cu6Sn5 layer; 33, Sn layer; 40, Sealed cavity. Detailed Implementation

[0041] 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.

[0042] In this invention, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing the invention and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0043] Furthermore, in addition to indicating direction or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in certain situations to indicate a dependency or connection. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0044] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this invention based on the specific circumstances.

[0045] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (the specific types and constructions may be the same or different), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0046] The following will be described in detail with reference to the accompanying drawings.

[0047] Example 1

[0048] See Figures 1 to 4 As shown, according to an embodiment of the present invention, a method for preparing a heat spreader is provided, which is used to prepare a heat spreader as shown in the figure. Figures 1 to 3 The heat spreader shown in the image.

[0049] like Figure 4 As shown, the preparation method of the heat spreader in this embodiment specifically includes the following steps:

[0050] Step 101: Prepare the first cover plate 10 and the second cover plate 20. (e.g.) Figure 5 As shown, this step includes:

[0051] Step 1011: Form the first cover plate 10 and the second cover plate 20 using copper plates. Copper has excellent heat dissipation properties; using copper plates to form the first cover plate 10 and the second cover plate 20 ensures the heat dissipation effect of the heat spreader. The first cover plate 10 and the second cover plate 20 can be square, circular, triangular, trapezoidal, elliptical, polygonal, or other irregular shapes. The specific shape can be adjusted and selected according to the actual application scenario of the heat spreader; no specific limitation is made in this embodiment. In actual processing, the first cover plate 10 and the second cover plate 20 can be formed by stamping, cutting, milling, injection molding, or finishing processes, which are simple to operate and have low manufacturing costs.

[0052] Step 1012: Pickling the first cover plate 10 and the second cover plate 20. After forming the first cover plate 10 and the second cover plate 20 using copper plates, pickling the first cover plate 10 and the second cover plate 20 is performed using a hydrochloric acid solution. Specifically, in this embodiment, a hydrochloric acid solution with a concentration of 5% to 7% can be used to pickle the first cover plate 10 and the second cover plate 20, wherein the concentration of the hydrochloric acid solution can be, for example, 5%, 6%, or 7%. It is understood that the concentration of the hydrochloric acid solution in this embodiment refers to the mass percentage concentration of the solution, that is, the concentration of the hydrochloric acid solution in this embodiment = mass of hydrochloric acid / mass of hydrochloric acid solution * 100%. After pickling the first cover plate 10 and the second cover plate 20 with a hydrochloric acid solution, on the one hand, grease and organic matter on the surface of the first cover plate 10 and the second cover plate 20 can be removed, and on the other hand, it can prevent the first cover plate 10 and the second cover plate 20 made of copper from being corroded by an excessively high concentration of hydrochloric acid solution. Alternatively, in other embodiments of the present invention, sulfuric acid, phosphoric acid, nitric acid, hydrofluoric acid, or a mixture of sulfuric acid, phosphoric acid, nitric acid, hydrofluoric acid, etc., with a concentration of 5% to 7% may be used to acid wash the first cover plate 10 and the second cover plate 20.

[0053] Step 1013: Micro-etch the first cover plate 10 and the second cover plate 20. In this step, a sodium persulfate solution is used to micro-etch the first cover plate 10 and the second cover plate 20. Specifically, in this embodiment, a sodium persulfate solution with a concentration of 2% to 5% can be used to micro-etch the first cover plate 10 and the second cover plate 20, wherein the concentration of sodium persulfate can be, for example, 2%, 3%, 4%, or 5%. It is understood that the concentration of sodium persulfate solution in this embodiment refers to the mass percentage concentration of the solution, that is, the concentration of sodium persulfate solution in this embodiment = mass of sodium persulfate solution / mass of sodium persulfate solution * 100%. After micro-etching the first cover plate 10 and the second cover plate 20 with sodium persulfate solution, on the one hand, the surfaces of the first cover plate 10 and the second cover plate 20 can be made smoother and flatter, providing a more reliable foundation for the preparation of the connecting layer 30; on the other hand, it can also prevent the first cover plate 10 and the second cover plate 20 from being severely corroded by an excessively high concentration of sodium persulfate solution. Of course, in other embodiments of the present invention, acidic solutions such as hydrochloric acid can also be used to micro-etch the first cover plate 10 and the second cover plate 20.

[0054] Step 102: A connecting layer 30 is formed at the outer contour edges of the first cover plate 10 and the second cover plate 20, and the melting point of the connecting layer 30 is lower than that of the first cover plate 10 and the second cover plate 20. In this step, the first cover plate 10 and the second cover plate 20 are subjected to tin-melting treatment using a tin-melting solution to form the aforementioned connecting layer 30 at the outer contour edges of the first cover plate 10 and the second cover plate 20. In step 102, the reaction principle of the tin-melting treatment is: 2Cu + Sn2+ (Divalent tin ion) → 2Cu + (monovalent copper ion) + Sn.

[0055] It is understood that the tin-refining solution in this embodiment is an acidic solution containing tin, for example, tin can be added to hydrochloric acid to form an acidic solution. In this embodiment, a layer of tin is deposited on the first cover plate 10 and the second cover plate 20 using the tin-refining solution, thereby forming a connecting layer 30. This connecting layer 30 is a tin-refined layer. The resulting first cover plate 10 and second cover plate 20 have smooth, flat, and dense surfaces, and the first cover plate 10 and second cover plate 20 are less prone to cracking (the phenomenon of cracks in the first cover plate 10 and the second cover plate 20) or bursting (the phenomenon of through holes in the first cover plate 10 and the second cover plate 20), thus ensuring the structural strength and stability of the first cover plate 10 and the second cover plate 20.

[0056] Furthermore, tin has a melting point of 231.89°C, while the first cover plate 10 and the second cover plate 20, which are made of copper, have a melting point of 1083.4°C. In other words, the melting point of tin is much lower than that of the first cover plate 10 and the second cover plate 20. Therefore, when performing diffusion soldering on the first cover plate 10 and the second cover plate 20, the temperature requirement for diffusion soldering is not so high, which facilitates diffusion soldering.

[0057] In other embodiments of the present invention, the connecting layer 30 may also be an aluminum layer (melting point of 660°C) sputtered onto the outer contour edges of the first cover plate 10 and the second cover plate 20, or other metal materials, alloy materials, or other materials with high structural strength, such as copper.

[0058] See Figure 6 As shown, step 102 includes the following steps:

[0059] Step 1021, Pre-dip. In this step, the first cover plate 10 and the second cover plate 20 are pre-dipped with the first tin-refining solution, which can improve the poor tin whisker.

[0060] Step 1022, Immersion. In this step, the first cover plate 10 and the second cover plate 20 are immersed in the second tin-plating solution so that tin in the tin-plating solution is deposited on the surface of the first cover plate 10 and the second cover plate 20, thereby preparing a connecting layer 30 of a certain thickness.

[0061] It is understood that the tin content in the first tin-melting solution during the pre-immersion of the first cover plate 10 and the second cover plate 20 is less than the tin content in the second tin-melting solution during the immersion step. That is, in the process of forming the connecting layer 30 on the first cover plate 10 and the second cover plate 20, the first pre-immersion of the first cover plate 10 and the second cover plate 20 using the first tin-melting solution with a lower tin content allows for a slow tin-melting process, improving tin whisker defects. Then, the second tin-melting solution with a higher tin content is used for immersion. This preparation method ensures the density and surface flatness of the tin-melting layer on the first cover plate 10 and the second cover plate 20, thereby improving the structural strength of the final heat spreader and the ease of diffusion soldering. In the actual preparation of the connecting layer 30, as long as a connecting layer with a thickness of 0.5 μm to 2.0 μm can be formed, this application does not specifically limit the tin content of the tin-melting solution.

[0062] like Figure 3 As shown, the bonding layer 30 formed through tinning includes a Cu3Sn layer 31, a Cu6Sn5 layer 32, and a Sn layer 33 stacked sequentially. The Cu3Sn layer 31 is disposed abutting the surfaces of the corresponding first cover plate 10 and the corresponding second cover plate 20. The Sn layer 33 is disposed away from the surface of either the first cover plate 10 or the second cover plate 20. The Cu6Sn5 layer 32 is located between the Sn layer 33 and the Cu3Sn layer 31. That is, in the direction away from the surfaces of the first cover plate 10 and the second cover plate 20, the Sn content gradually increases, and the copper content gradually decreases, ultimately forming a Sn surface layer.

[0063] It is understood that Cu3Sn indicates that in the Cu3Sn layer 31, the mass ratio of copper to tin in the copper-tin alloy is approximately 3:1; Cu6Sn5 indicates that in the Cu6Sn5 layer 32, the mass ratio of copper to tin in the copper-tin alloy is approximately 6:5.

[0064] During the immersion process, the tinning process is stopped when the thickness of the interconnect layer 30 reaches 0.5 μm to 2.0 μm. Specifically, the thickness of the interconnect layer 30 is the thickness in the direction perpendicular to the surface of the interconnect layer 30, that is, the thickness from the surface of the interconnect layer 30 to the surface of the first cover plate 10 or the second cover plate 20. Optionally, the thickness of the interconnect layer 30 can be 0.5 μm, 0.7 μm, 0.9 μm, 1.1 μm, 1.3 μm, 1.5 μm, 1.7 μm, 1.8 μm, or 2.0 μm, etc. In this application, the thickness of the interconnect layer 30 is preferably 0.8 μm to 1.2 μm.

[0065] Optionally, the thickness of the Cu3Sn layer 31 in the direction perpendicular to the connecting layer 30 is 0.05um to 0.15um, such as 0.05um, 0.08um, 0.12um or 0.15um.

[0066] Optionally, the thickness of the Cu6Sn5 layer 32 in the direction perpendicular to the connecting layer 30 is 0.25um to 0.35um, for example, 0.25um, 0.3um or 0.35um.

[0067] Optionally, the thickness of the Sn layer 33 in the direction perpendicular to the connecting layer 30 is 0.5um to 0.7um, such as 0.5um, 0.6um or 0.7um.

[0068] As can be seen, in the direction away from the surface of the first cover plate 10 and the second cover plate 20, the Sn content of the connecting layer 30 in this application gradually increases, and the thickness of the Sn layer 33 is greater than the thickness of the Cu3Sn layer 31 and the Cu6Sn5 layer 32, which facilitates diffusion welding.

[0069] Step 103: Use diffusion welding to weld and fix the connecting layer 30 on the first cover plate 10 and the connecting layer 30 on the second cover plate 20 into one piece so that the first cover plate 10 and the second cover plate 20 surround and form a sealed cavity 40.

[0070] Diffusion welding is a solid-state welding method that places closely contacting workpieces in a vacuum or protective atmosphere and maintains them at a certain temperature and pressure for a period of time, allowing atoms at the contact interface to diffuse and achieve a reliable connection. Before diffusion welding, the material surface is usually machined, ground, polished, and cleaned. However, regardless of the pre-welding processing, the processed material surface remains microscopically rough and often covered with an oxide film. In this application, a connecting layer 30 is obtained by tinning on the first cover plate 10 and the second cover plate 20. The outer surface of this connecting layer 30 is a tin layer. Tin's melting point is much lower than that of copper, so the temperature requirement for diffusion welding is not as high, and the copper base does not melt when the tin melts, thus preserving the copper base structure well. Furthermore, because tin has a lower melting point, the melting time at the weld joint is shorter during diffusion welding, which improves the production efficiency of the heat spreader and reduces its production cost.

[0071] In summary, during the preparation of the heat spreader, the present invention first performs tin melting treatment on the outer edge contours of the first cover plate 10 and the second cover plate 20 of the heat spreader to form a connecting layer 30. The connecting layer 30 is a tin melting layer, and the outer surface of the tin melting layer is tin. The melting point of tin (231.89℃) is much lower than that of copper (1083.4℃). Therefore, the temperature requirement is not as high during subsequent diffusion soldering, and the copper base does not melt when the tin melts, which can well maintain the copper base structure. In addition, the melting time at the solder joint is relatively short, which can improve the production efficiency of the heat spreader and reduce the production cost of the heat spreader.

[0072] Example 2

[0073] See Figures 1 to 3 As shown, according to an embodiment of the present invention, a heat spreader is provided, which is prepared by the heat spreader preparation method described in Embodiment 1 above. The heat spreader includes a first cover plate 10 and a second cover plate 20, which surround to form a sealed cavity 40. A connecting layer 30 is provided on the outer edge contour of the first cover plate 10 and the outer edge contour of the second cover plate 20. The connecting layer 30 of the first cover plate 10 and the connecting layer 30 of the second cover plate 20 are connected by diffusion welding.

[0074] Since the outer edge contours of the first cover plate 10 and the second cover plate 20 in this embodiment have a connecting layer 30, which is a tin-plated layer, the outer surface of which is tin. The melting point of tin (231.89℃) is much lower than that of copper (1083.4℃). Therefore, the temperature requirement is not so high during subsequent diffusion soldering, and the copper base does not melt when the tin melts, which can well maintain the copper base structure. In addition, the melting time at the solder joint is relatively short, which can improve the production efficiency of the heat spreader and reduce the production cost of the heat spreader.

[0075] Example 3

[0076] According to embodiments of the present invention, an electronic device is provided, which may be, for example, a mobile phone, tablet, laptop computer, or other electronic product. The electronic device includes the heat spreader described in Embodiment 2. Since the electronic device in this embodiment has the heat spreader of Embodiment 2, it enjoys the beneficial effects of the aforementioned heat spreader, which will not be elaborated further here.

[0077] The above provides a detailed description of an electronic device, a vapor chamber, and a method for preparing a vapor chamber according to embodiments of the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the embodiments above are only for the purpose of helping to understand the electronic device, the vapor chamber, and the method for preparing a vapor chamber, as well as the core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing a heat spreader, characterized in that, Includes the following steps: Prepare the first cover plate and the second cover plate; A connecting layer is formed at the outer contour edge of the first cover plate and the second cover plate, wherein the melting point of the connecting layer is lower than the melting point of the first cover plate and the second cover plate; as well as Diffusion welding is used to weld and fix the connecting layer on the first cover plate and the connecting layer on the second cover plate into one piece so that the first cover plate and the second cover plate form a sealed cavity. The step of forming a connecting layer at the outer contour edges of the first cover plate and the second cover plate includes: treating the first cover plate and the second cover plate with a tin-melting solution to form the connecting layer at the outer contour edges of the first cover plate and the second cover plate; The step of treating the first cover plate and the second cover plate with a tin-melting solution to form the connecting layer at the outer contour edges of the first cover plate and the second cover plate includes: The first cover plate and the second cover plate are pre-impregnated using a first tin oxide solution; and The first cover plate and the second cover plate were immersed in a second tin oxide solution; The tin content in the first tin-ion solution is less than the tin content in the second tin-ion solution.

2. The method for preparing a heat spreader according to claim 1, characterized in that, The steps for preparing the first cover plate and the second cover plate include: The first cover plate and the second cover plate are formed by processing copper plates; The first cover plate and the second cover plate are pickled; and Micro-etching is performed on the first cover plate and the second cover plate.

3. The method for preparing a heat spreader according to claim 2, characterized in that, During the pickling process of the first cover plate and the second cover plate, a hydrochloric acid solution with a concentration of 5% to 7% is used to pickle the first cover plate and the second cover plate; and / or, During the micro-etching process of the first cover plate and the second cover plate, a sodium persulfate solution with a concentration of 2% to 5% is used to perform micro-etching on the first cover plate and the second cover plate.

4. The method for preparing a heat spreader according to any one of claims 1 to 3, characterized in that, The thickness of the connecting layer is 0.5 μm to 2.0 μm in a direction perpendicular to the surface of the connecting layer.

5. The method for preparing a heat spreader according to any one of claims 1 to 3, characterized in that, The connecting layer includes a Cu3Sn layer, a Cu6Sn5 layer and a Sn layer stacked sequentially, with the Cu3Sn layer abutting the surface of the first cover plate and the surface of the second cover plate.

6. The method for preparing a heat spreader according to claim 5, characterized in that, In the direction perpendicular to the connecting layer, the thickness of the Cu3Sn layer is 0.05 μm to 0.15 μm; and / or, The thickness of the Cu6Sn5 layer is 0.25 μm to 0.35 μm; and / or, The thickness of the Sn layer is 0.5 μm to 0.7 μm.

7. A heat spreader, characterized in that, The heat spreader is prepared by the heat spreader preparation method according to any one of claims 1 to 6. The heat spreader includes a first cover plate and a second cover plate. The first cover plate and the second cover plate surround a sealed cavity. The outer edge contours of the first cover plate and the outer edge contours of the second cover plate are provided with a connecting layer. The connecting layer of the first cover plate and the connecting layer of the second cover plate are connected by diffusion welding.

8. An electronic device, characterized in that, The electronic device includes the heat spreader as described in claim 7.

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