Aluminum nitride ceramic copper-plated vapor chamber and preparation method thereof

Abstract

The invention provides an aluminum nitride ceramic copper-plated vapor chamber and a preparation method thereof, and belongs to the technical field of vapor chamber manufacturing. The preparation method comprises the following steps: taking copper as a target material, and carrying out magnetron sputtering on an aluminum nitride ceramic substrate to obtain an aluminum nitride copper-plated material; the aluminum nitride copper-plated material serves as an evaporation end shell plate, deposition is conducted on the evaporation end shell plate through an electro-deposition method, a first capillary core layer is obtained, and the evaporation end shell plate with the first capillary core layer is obtained; depositing on the condensation end shell plate by adopting an electro-deposition method to obtain a second capillary core layer; a condensation end shell plate with a second capillary core layer is obtained; and the evaporation end shell plate with the first capillary core layer and the condensation end shell plate with the second capillary core layer are packaged after being subjected to heat treatment, and the aluminum nitride ceramic copper-plated vapor chamber based on the electro-deposition gradient capillary core is obtained. The heat dissipation efficiency, the heat uniformity and the mechanical reliability of the vapor chamber are remarkably improved by changing the structural design of the capillary core and the material selection of the substrate.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature averaging plate manufacturing, and more particularly to an aluminum nitride ceramic copper-plated temperature averaging plate and a preparation method thereof. Background Art

[0002] As electronic devices evolve toward higher power, miniaturization, and increased integration, thermal management has become a key constraint on performance and reliability. In high-heat-flux environments, traditional heat dissipation methods (such as air cooling systems) often struggle to meet the demands for rapid heat transfer and uniform distribution. Therefore, vapor chambers, as highly efficient thermal management devices, have become a crucial technology in the electronics cooling field due to their excellent heat transfer performance, compact structure, and high thermal conductivity uniformity.

[0003] The vapor chamber utilizes the principle of gas-liquid phase transition. Coolant within a vacuum chamber with a microstructured inner wall vaporizes under low vacuum conditions. After absorbing heat, it expands and fills the entire chamber. Condensation occurs in the cold areas, releasing heat that then flows back to the heat source via capillary channels, forming a cycle and effectively dissipating heat. The design of the internal capillary wick directly impacts the overall performance of the vapor chamber. Capillary force and permeability are commonly used to evaluate capillary wick performance. Capillary force and permeability are often contradictory: for a given porosity, a larger effective pore size results in a smaller capillary force, while a smaller effective pore size results in a greater capillary force. Optimal heat transfer performance requires a balance between capillary force and permeability. Traditional wicks have only one capillary structure in a given direction. However, a stepped structure reduces wick thickness while maintaining capillary force, while also offering higher heat transfer capabilities.

[0004] Existing capillary wick fabrication methods (such as sintering, meshing, or etching) have limitations in achieving complex structures and optimizing performance. To improve the heat transfer efficiency and applicability of vapor chambers, exploring new capillary wick fabrication technologies has become a research hotspot.

[0005] Traditional vapor chambers are typically made of metal materials (such as copper or aluminum). However, there is often a mismatch in thermal expansion coefficients between the vapor chamber and the chip, making it difficult to effectively integrate them into an integrated package. Summary of the Invention

[0006] To address the above issues, the present invention provides an aluminum nitride ceramic copper-plated heat spreader based on an electrodeposited gradient capillary wick and a preparation method. The evaporation end shell plate of the present invention uses an aluminum nitride ceramic copper-plated substrate prepared by magnetron sputtering, and the condensation end uses a copper substrate, which effectively solves the thermal stress problem caused by the mismatch between the thermal expansion coefficient and the chip. In addition, the gradient capillary wick is prepared by an electrodeposition process, and a gradient distribution of porosity and pore size is achieved by adjusting process parameters such as current density. The present invention provides a method for significantly improving the heat dissipation efficiency, thermal uniformity, and mechanical reliability of the heat spreader by changing the capillary wick structure design and substrate material selection.

[0007] The first object of the present invention is to provide a method for preparing an aluminum nitride ceramic copper-plated temperature-equalizing plate based on an electrodeposited gradient capillary core, comprising the following steps: Using copper as the target, magnetron sputtering was performed on an aluminum nitride ceramic substrate at a sputtering power of 200W~300W to obtain aluminum nitride copper-plated material.

[0008] The aluminum nitride copper-plated material was used as the evaporation end shell plate. Electrodeposition was performed on the evaporation end shell plate at a current density of 0.8 A / cm 2 ~1A / cm 2 Deposition is performed under the following conditions to obtain a first capillary core layer, thereby obtaining an evaporation end shell plate with the first capillary core layer.

[0009] Electrodeposition was performed on the condenser end shell at a current density of 0.3 A / cm 2 ~1.5A / cm 2 Deposition is performed under the following conditions to obtain a second capillary core layer; and a condensation end shell plate with the second capillary core layer is obtained.

[0010] The evaporation end shell plate with the first capillary core layer and the condensation end shell plate with the second capillary core layer are heat-treated at 700°C to 750°C and then packaged to obtain an aluminum nitride ceramic copper-plated temperature-averaging plate based on electrodeposited gradient capillary cores.

[0011] In a preferred embodiment of the present invention, during magnetron sputtering, the sputtering time is 60 min to 100 min, and the flow rate of argon gas is 50 sccm to 60 sccm.

[0012] In a preferred embodiment of the present invention, during electrodeposition, the electrolyte consists of sulfuric acid and CuSO4 solution.

[0013] In the electrolyte, the concentration of sulfuric acid is 1.4 mol / L~1.6 mol / L, and the concentration of CuSO4 is 0.3 mol / L~0.5 mol / L.

[0014] In a preferred embodiment of the present invention, during electrodeposition, the deposition time is 200s to 400s.

[0015] In a preferred embodiment of the present invention, the heat treatment time is 30 min to 40 min.

[0016] In a preferred embodiment of the present invention, the packaging method is to use vacuum brazing to connect.

[0017] In a preferred embodiment of the present invention, the condensing end shell plate is made of red copper.

[0018] The second object of the present invention is to provide an aluminum nitride ceramic copper-plated temperature equalizing plate prepared by the above preparation method.

[0019] In a preferred embodiment of the present invention, it includes: a condensing end shell plate, an evaporating end shell plate, a first capillary core layer, a second capillary core layer, an injection tube and a support column; the condensing end shell plate and the evaporating end shell plate form a closed structure, the inner surface of the condensing end shell plate is provided with a cavity, the support column is arranged in the cavity to form a condensing end shell plate containing a support column, the second capillary core layer is deposited on the condensing end shell plate containing the support column, the first capillary core layer is deposited on the second capillary core layer, and the injection tube is arranged on one side of the condensing end shell plate.

[0020] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses copper-plated aluminum nitride ceramic as the evaporation end material, making full use of its high thermal conductivity and electrical insulation, which can effectively solve the thermal stress problem caused by the mismatch of thermal expansion coefficients between the chip and the evaporation end. It can achieve good integration with power devices, and the high temperature tolerance of aluminum nitride ceramics also makes it suitable for use in high power density heat dissipation scenarios. In order to further enhance the mechanical strength of aluminum nitride ceramics and improve their thermal conductivity, copper is usually plated on their surface. This method not only improves the bonding strength of the material, but also further improves the overall heat dissipation performance. In addition, this design realizes a tight integrated package between the heat spreader and the chip, ensuring a stable thermal connection and efficient heat transfer performance between the two, and ensuring the reliability of the chip in high power and high temperature working environments. In addition, the present invention adopts an electroplating process to prepare a gradient capillary core, and achieves a gradient distribution of porosity and pore size by adjusting process parameters such as current density. This process optimizes the circulation path and evaporation-condensation efficiency of the working fluid, enhances the liquid evaporation capacity of the evaporation end and the liquid reflux capacity of the condensation end, significantly improves the circulation efficiency of the working fluid, and thus effectively improves the overall thermal conductivity performance of the heat spreader. Compared to conventional sintering methods (porosity ≤50%, minimum pore size ≥20μm) for capillary wick structures, the electrodeposition method can produce capillary wicks with porosity as high as 80% in the evaporation zone, while achieving a dense structure with minimum pore sizes of ≤20μm and ≤5μm in the evaporation and condensation zones. This gradient design improves the capillary force of the vapor chamber by 30% and increases permeability by 25%.

[0021] (2) The combination of aluminum nitride ceramic copper-plated substrate and copper material provides excellent mechanical strength. At the same time, the application of copper material at the condensing end greatly improves the ability of heat to be quickly dissipated from the condensing end. This structure can effectively cope with long-term, high-temperature, and high-heat flux working conditions, ensuring that the temperature plate can still operate stably in extreme environments, extending the service life of the equipment.

[0022] (3) The vapor chamber produced by the present invention combines high heat dissipation performance with lightweight and thin features, making it suitable for a variety of applications, including high-power density miniaturized electronic devices (such as smartphones, laptops, servers, etc.), new energy vehicle battery management systems, and aerospace equipment. Through innovative design, the present invention provides a multifunctional solution for efficient thermal management technology, meeting the needs of modern electronic products for efficient heat dissipation and lightweight design. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a three-dimensional structural diagram of the aluminum nitride ceramic copper-plated temperature equalizing plate of the present invention.

[0024] Figure 2 This is a three-dimensional diagram of the evaporation end shell plate of the present invention.

[0025] Figure 3 This is a front view of the evaporation end shell plate of the present invention.

[0026] Figure 4 This is a top view of the evaporation end shell plate of the present invention.

[0027] Figure 5 This is a three-dimensional diagram of the condensing end shell plate and support columns of the present invention.

[0028] Figure 6 This is a front view of the condensing end shell plate and support column of the present invention.

[0029] Figure 7 It is a top view of the condensing end shell plate and support column of the present invention.

[0030] Figure 8 It is a front view of the liquid injection tube of the present invention.

[0031] Figure 9 It is the left view of the liquid injection tube of the present invention.

[0032] Figure 10 It is a cross-sectional view of the condensation end shell plate with the second capillary core layer of the present invention.

[0033] in: 1- condensation end shell plate; 2- evaporation end shell plate; 3- first capillary core layer; 4- liquid injection pipe; 5- support column, 6- second capillary core layer. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] Example 1 This embodiment provides an aluminum nitride ceramic copper-clad temperature plate based on an electrodeposited gradient capillary core; Figure 1 As shown, the aluminum nitride ceramic copper-clad temperature equalizer consists of a condenser shell plate 1, an evaporator shell plate 2, a first capillary wick layer 3, a second capillary wick layer 6, an injection tube 4, and a support column 5. The condenser shell plate 1 and the evaporator shell plate 2 are located on either side of the temperature equalizer, forming a closed circulation structure for supporting and sealing the internal capillary wicks and working fluid. The first capillary wick layer 3 is deposited on the evaporator shell plate 2, and the second capillary wick layer 6 is deposited on the condenser shell plate 1. The injection tube 4 is provided on one side of the condenser shell plate 1.

[0036] The condensing end shell plate 1 is made of copper material, which has high thermal conductivity and good mechanical strength, ensuring that heat can be quickly conducted and effective condensation can be achieved under high heat flux density conditions. Figure 5 The three-dimensional structure of the condensing end shell plate 1 is shown, and its compact design ensures that the temperature distribution plate can effectively handle a large amount of heat. Figure 6 and Figure 7 The following are the front and top views of the condensing end shell 1, showing the geometric design and layout of the condensing end shell 1. Specifically, the inner surface of the condensing end shell 1 is provided with a concave rounded square cavity, and the support columns 5 are evenly distributed in the concave rounded square cavity. The support columns 5 are square cross-section support columns. Furthermore, the size of the condensing end shell 1 is l 2× l 2× h 2. Both length and width are l 2=17mm, the overall height is h 2=1.4mm. The bottom plate thickness is 0.6mm, the narrow side of the weld is 1mm, and the cavity size is l 3× l 3× h 3. The length and width are l 3=15mm, the cavity height is h 3=0.8mm, there are 16 support columns evenly arranged in 4×4 patterns on the condensing end shell plate 1, and the size of a single support column is w 3× w 3× h 3. Both length and width are w 3=1mm, the height of a single support column is equal to the cavity heighth 3=0.8mm, the distance between two adjacent support pillars is 2.5mm, and the support pillars are evenly arranged. Figures 8 and 9 As shown, the outer diameter of the injection tube d 1=1mm, inner diameter d 2=0.8mm, length d 3=25mm.

[0037] The evaporation end shell 2 is primarily made of aluminum nitride ceramic copper-plated material, which has excellent thermal conductivity and electrical insulation. The evaporation end region of the internal electrodeposited gradient capillary wick has high porosity and large pore size, which facilitates the evaporation of the working fluid and the rapid conduction of heat. Figure 2 The three-dimensional structure of the evaporation end shell plate 2 is shown, and its surface has been precisely processed and cleaned to ensure the adhesion and uniformity of the electrodeposited capillary wick. Figure 3 and Figure 4 The front view and top view of the evaporation end shell plate 2 respectively show its geometric shape and connection structure. Similarly, the evaporation end shell plate 2 is correspondingly provided with a welded narrow edge.

[0038] The capillary structure component, located between the evaporation and condensation ends, comprises a first capillary core layer 3 and a second capillary core layer 6. Fabricated using electrodeposition technology, these channels or pores are meticulously distributed throughout the vapor chamber, forming a highly efficient liquid circulation network. These channels not only drive the liquid back from the condensation zone to the evaporation zone through capillary action, maintaining the dynamic equilibrium of the liquid within the vapor chamber, but also ensure rapid heat conduction and uniform distribution, significantly improving the overall thermal conductivity and performance of the vapor chamber.

[0039] The injection pipe 4 is used to inject the working fluid into the interior of the heat spreader. The injection amount and liquid type of the working fluid (such as water, ethanol, hydrofluoroether HFE-7100, etc.) need to be adjusted according to the specific application requirements to ensure that the heat spreader can work stably under high heat flux conditions. The injection pipe 4 is designed to be located at an appropriate position on the heat spreader to ensure that the working fluid can be evenly distributed to the capillary wick structure inside the heat spreader, such as the present invention. Figure 1 As shown, the liquid injection pipe 4 is arranged on one side of the condensing end shell plate 1.

[0040] Further, such as Figure 3~Figure 4 As shown, the size of the evaporation end shell plate 2 is l 1× l 1× h 1. Both length and width are l 1=17mm, the overall height is h 1=0.6mm. The aluminum nitride ceramic substrate is h 1-1 =0.5mm, the thickness of the copper plating ish 1-2 =0.1mm. The thickness of the electrodeposited capillary core at the evaporation end is 0.2mm.

[0041] The support column 5 is provided to provide a solid support for the subsequent vacuum operation, effectively preventing the structure from collapsing and the bulging phenomenon that may occur during operation. The support column 5 and the condensing end shell plate 1 are integrally formed by machine tool processing.

[0042] The heat spreader of the present invention combines a condenser shell 1, an evaporator shell 2, a first capillary wick layer 3, a second capillary wick layer 6, support columns 5, and an injection tube 4 to form a highly efficient thermal management system. The innovative design of the electrodeposited gradient capillary wick allows for rapid evaporation and reflow of the working fluid within the heat spreader, significantly improving heat transfer efficiency. This heat spreader's structural design is suitable for miniaturized, high-power-density electronic devices, offering excellent, stable, and reliable heat dissipation performance, meeting the thermal management requirements of modern high-performance devices.

[0043] Example 2 Preparation of evaporation end shell plate 2: A 0.1 mm copper layer was deposited on the surface of aluminum nitride ceramic by magnetron sputtering. First, the aluminum nitride ceramic substrate was placed in a vacuum chamber and cleaned with an argon ion beam (energy 200 eV) for 10 minutes. Then, a copper target with a purity of 99.999% was used for sputtering at a power of 200 W for 60 minutes.

[0044] Preparation of electrodeposition gradient capillary core: Place the aluminum nitride ceramic copper-plated substrate that has been ultrasonically cleaned in an electrodeposition tank. The solvent used in the electrolyte is water, the concentration of sulfuric acid is 1.5 mol / L, the concentration of CuSO4 is 0.5 mol / L, the current density is adjusted to 1 A / cm², and the deposition time is 300 seconds to form the first capillary core layer 3; Figure 2 Under this deposition condition, larger pore size and higher porosity are formed, which is conducive to the rapid evaporation of the liquid.

[0045] The condensation end shell plate containing the support column is placed in an electrodeposition tank. The same electrolyte is used. Specifically, the solvent used in the electrolyte is water, the concentration of sulfuric acid is 1.5 mol / L, and the concentration of CuSO4 is 0.5 mol / L. However, the current density is increased to 1.5 A / cm², and the deposition time is also 300 seconds to form a second capillary core layer 6, thereby obtaining a condensation end shell plate with a second capillary core layer. Figure 10 Under this deposition condition, smaller pore size and lower porosity are formed, thereby enhancing the reflux capacity of the condensed liquid.

[0046] By adjusting the process parameters in this way, a first capillary wick layer 3 and a second capillary wick layer 6 are formed, achieving a gradient distribution of the capillary wick structure. It should be noted that when depositing the condenser end shell plate 1 and the evaporator end shell plate 2, a mask is required to cover the narrow welding edge to facilitate welding in subsequent steps.

[0047] After the electrodeposition is completed, the evaporation end shell plate with the first capillary wick layer and the condensation end shell plate with the second capillary wick layer are kept at 720°C for 30 minutes for appropriate post-treatment (heat treatment) to enhance their structural stability and thermal conductivity.

[0048] The electrodeposited evaporation end shell with the first capillary core layer and the condensation end shell with the second capillary core layer are packaged into a single structure in a vacuum sintering furnace. Lead-free solder with a melting point of 220°C is applied to the narrow solder joint and support pillars. The solder is sintered at 230°C for 30 minutes and then held at this temperature for 40 minutes to ensure a firm bond between the two parts.

[0049] Finally, a molecular pump is used to evacuate the welded vapor chamber to a vacuum state, and an appropriate amount of working fluid is injected into the chamber through the injection tube. This process forms an evaporation-condensation cycle for the vapor chamber, ensuring efficient heat transfer during operation.

[0050] This invention provides a method for preparing an aluminum nitride ceramic copper-plated heat spreader based on an electrodeposited gradient wick. This method effectively addresses existing issues such as insufficient heat dissipation, mismatched thermal expansion coefficients, and complex structures in heat spreaders used in high-power density heat dissipation applications. By innovatively utilizing an aluminum nitride ceramic substrate and an electrodeposited gradient wick structure, it achieves efficient and stable heat dissipation.

[0051] Specifically, the present invention uses copper-plated aluminum nitride ceramic as the evaporation end material of the heat spreader. Combined with its high thermal conductivity and electrical insulation, it effectively solves the thermal stress problem caused by the mismatch in thermal expansion coefficients between the chip and the heat spreader, thereby achieving an integrated package of the chip and the heat spreader and ensuring stable thermal management. The condensation end uses high-thermal-conductivity copper material, further enhancing the ability to quickly dissipate heat from the condensation end. A gradient capillary wick structure is prepared using electrodeposition technology. This structure optimizes the circulation path of the working fluid and the evaporation-condensation efficiency, allowing the heat spreader to maintain efficient thermal conductivity in high heat flux environments.

[0052] The heat spreader of this invention achieves a small and thin structure, with an overall size of 17 mm × 17 mm × 2 mm, meeting the heat dissipation requirements of miniaturized, high-power density electronic devices. Furthermore, through the rational design of the electrodeposited gradient capillary wick, the fluid circulation system is optimized, improving the thermal uniformity and long-term stability of the heat spreader.

[0053] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0054] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing an aluminum nitride ceramic copper-plated temperature-equalizing plate, characterized in that: The following steps are involved: Using copper as the target, magnetron sputtering was performed on an aluminum nitride ceramic substrate at a sputtering power of 200W to 300W to obtain aluminum nitride copper-plated material; The aluminum nitride copper-plated material is used as the evaporation end shell plate (2), and an electrodeposition method is used on the evaporation end shell plate (2) at a current density of 0.8A / cm 2 ~1A / cm 2 Deposition is performed to obtain a first capillary core layer (3), thereby obtaining an evaporation end shell plate having the first capillary core layer; Electrodeposition was performed on the condensing end shell plate (1) at a current density of 0.3 A / cm 2 ~1.5A / cm 2 Deposition is performed under the following conditions to obtain a second capillary core layer (6); a condensation end shell plate with the second capillary core layer is obtained; The evaporation end shell plate with the first capillary core layer and the condensation end shell plate with the second capillary core layer are heat-treated at 700°C to 750°C and then packaged to obtain an aluminum nitride ceramic copper-plated temperature-averaging plate based on electrodeposited gradient capillary cores.

2. The method for preparing an aluminum nitride ceramic copper-plated temperature equalizing plate according to claim 1, characterized in that: During magnetron sputtering, the sputtering time is 60 min~100 min, and the flow rate of argon gas is 50 sccm~60 sccm.

3. The method for preparing an aluminum nitride ceramic copper-plated temperature equalizing plate according to claim 1, characterized in that: During electrodeposition, the electrolyte consists of sulfuric acid and CuSO4 solution; In the electrolyte, the concentration of sulfuric acid is 1.4mol / L~1.6mol / L, and the concentration of CuSO4 is 0.3mol / L~0.5mol / L.

4. The method for preparing an aluminum nitride ceramic copper-plated temperature equalizing plate according to claim 1, characterized in that: During electrodeposition, the deposition time is 200s~400s.

5. The method for preparing an aluminum nitride ceramic copper-plated temperature equalizing plate according to claim 1, characterized in that: The heat treatment time is 30min~40min.

6. The method for preparing an aluminum nitride ceramic copper-plated temperature equalizing plate according to claim 1, characterized in that: The packaging method is to use vacuum brazing method for connection.

7. The method for preparing an aluminum nitride ceramic copper-plated temperature equalizing plate according to claim 1, characterized in that: The condensing end shell plate (1) is made of copper.

8. An aluminum nitride ceramic copper-plated temperature equalizing plate prepared by the preparation method according to any one of claims 1 to 7.

9. The aluminum nitride ceramic copper-plated temperature equalizing plate according to claim 8, characterized in that: include: A condensing end shell plate (1), an evaporating end shell plate (2), a first capillary core layer (3), a second capillary core layer (6), an injection pipe (4) and a support column (5); the condensing end shell plate (1) and the evaporating end shell plate (2) form a closed structure, the inner surface of the condensing end shell plate (1) is provided with a cavity, the support column (5) is arranged in the cavity to form a condensing end shell plate containing the support column, the second capillary core layer (6) is deposited on the condensing end shell plate containing the support column, the first capillary core layer (3) is deposited on the second capillary core layer (6), and the injection pipe (4) is arranged on one side of the condensing end shell plate (1).

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