Press-fit preparation method of high-thermal-conductivity circuit board and high-thermal-conductivity circuit board

Abstract

The invention discloses a press-fit preparation method of a high-thermal-conductivity circuit board and the high-thermal-conductivity circuit board, and the preparation method comprises the steps: carrying out the dispersion and solidification of a liquid metal gallium-indium alloy and fiber mixture in an inert argon atmosphere, and fusing with a substrate, and obtaining a self-adaptive heat-conduction substrate; carrying out gradient deposition and etching treatment on the self-adaptive heat conduction base material to obtain a gradient spacing template; carrying out electrospinning infiltration and heat treatment on the gradient spacing template to obtain a base material containing a dynamic heat-conducting network; conducting layer pre-pressing treatment is conducted on the base material containing the dynamic heat conduction network, and a pre-assembled plate is obtained; performing staged dynamic pressing treatment on the pre-assembled board to obtain a molded circuit board; and performing surface spraying and deposition treatment on the molded circuit board to obtain the high-thermal-conductivity circuit board. The problems of poor heat flow path, poor interface bonding performance and the like in the prior art are solved, the heat management effect is remarkably improved, and the reliability and performance of an electronic product are remarkably improved.

Description

Technical Field

[0001] The present application relates to the technical field of circuit board preparation, and in particular to a press-fit preparation method for a high thermal conductivity circuit board and a high thermal conductivity circuit board. Background Art

[0002] With the increasing power density of electronic devices, especially in the application of high-power electronic devices and integrated circuits, good thermal conductivity has become a key requirement for electronic packaging materials. Existing circuit board materials mostly use copper foil and epoxy resin composite materials, but due to their low thermal conductivity, these materials have significant heat accumulation problems in high-power electronic devices.

[0003] In the existing technology, the common means of improving thermal conductivity is mainly through the introduction of high thermal conductivity fillers, such as aluminum nitride (AlN), metallized carbon nanotubes, graphene, etc., but this type of technology mostly focuses on the thermal conductivity of the material itself, ignoring the impact of the overall structure of the circuit board on the heat flow, and in the pressing process, the uniform dispersion and interface bonding of the filler are poor, resulting in the effect of thermal conductivity in practical applications cannot be fully utilized. Even if modified fillers or composite materials are used, the existing technology cannot effectively solve the problems of heat flow path optimization and thermal interface effect based on the conventional pressing process.

[0004] Therefore, how to further improve the thermal conductivity of circuit boards while maintaining structural stability remains the main challenge facing current thermal management technology. Summary of the invention

[0005] The purpose of the present application is to provide a method for pressing and preparing a high thermal conductivity circuit board and a high thermal conductivity circuit board, so as to solve the technical problem that the existing pressing and preparing process of the high thermal conductivity circuit board cannot effectively improve the overall thermal conductivity of the circuit board.

[0006] To achieve this goal, this application adopts the following technical solutions: A method for laminating a high thermal conductivity circuit board, comprising: The liquid metal gallium-indium alloy and the fiber mixture are dispersed and solidified in an inert argon atmosphere, and fused with the matrix to obtain an adaptive thermal conductive substrate; Performing gradient deposition and etching on the adaptive thermal conductive substrate to obtain a gradient spacing template; The gradient spacing template is electrospun and heat treated to obtain a substrate containing a dynamic thermal conductive network; The substrate containing the dynamic heat-conducting network is subjected to a conductive layer pre-pressing treatment to obtain a pre-assembled plate; The pre-assembled panels are subjected to dynamic pressing treatment in stages to obtain a formed circuit board; The molded circuit board is subjected to surface spraying and deposition treatment to obtain the high thermal conductivity circuit board.

[0007] Furthermore, the step of dispersing and solidifying the liquid metal gallium-indium alloy and the fiber mixture in an inert argon atmosphere and fusing them with the matrix to obtain an adaptive thermal conductive substrate includes: The liquid metal gallium-indium alloy and the hydroxylated carbon fiber are mixed in a mass ratio of 1:3 to form a mixture, and the mixture is mechanically stirred at 500 rpm for 10 to 20 minutes in an inert argon atmosphere while applying low-frequency ultrasonic treatment to obtain a uniform suspension, wherein the molar mass ratio of gallium to indium in the liquid metal gallium-indium alloy is 4 to 5:1; Adding the uniform suspension to a mixed solution of a polyimide precursor solution and graphene oxide, and treating under ultrasonic conditions to obtain a composite precursor solution, wherein the mass ratio of the uniform suspension to the mixed solution is 1:5; Passing the composite precursor liquid into a microfluidic channel for layered shearing treatment, wherein the width of the microfluidic channel is 50 μm and the flow rate is 0.1 mL / min, and applying an alternating electric field in the channel to obtain a directional primary liquid; The oriented primary liquid is poured into a mold, and pre-cured in a vacuum oven at 100° C. for 40 minutes to obtain a primary cured substrate; Orienting the initially fixed substrate in a uniform magnetic field, and cooling it to room temperature at a rate of 5° C. / min to obtain an oriented substrate, wherein the direction of the magnetic field is parallel to the length direction of the fiber; The oriented substrate is subjected to heat pressing treatment in a nitrogen atmosphere to obtain the adaptive thermally conductive substrate.

[0008] Furthermore, the step of performing gradient deposition and etching on the adaptive thermal conductive substrate to obtain a gradient spacing template includes: Applying a silica gel layer of nano-alumina particles to the outer wall of the adaptive thermal conductive substrate to form a primary positioning substrate; Obtaining the surface characteristics of the primary positioning substrate, injecting an ethanol solution of polydimethylsiloxane and nano-carbon fiber with a preset concentration according to the surface characteristics for deposition treatment, forming a gradient layer with a thickness decreasing from 50 μm in the center to 5 μm at the edge, and obtaining a gradient thickness substrate; According to the distribution of the gradient thickness substrate, an ultraviolet laser with a preset power is used to etch the substrate longitudinally to form a V-shaped groove, thereby obtaining a periodic groove substrate with a gradient spacing, wherein the groove spacing increases from 50 μm at the center to 100 μm at the edge; Based on the vapor deposition technology, a suspension containing zinc oxide nanoparticles is injected into the surface of the periodic groove substrate to make the nanoparticles gradiently distributed along the groove depth direction to obtain the gradient spacing template, wherein the deposition pressure is 0.03~0.05MPa and the filling time is 10 minutes.

[0009] Furthermore, the step of etching longitudinally along the substrate using an ultraviolet laser of preset power to form a V-shaped groove according to the distribution of the gradient thickness substrate also includes: Scanning longitudinally along the gradient thickness substrate using a laser scanning device to collect reflected light intensity and phase difference data corresponding to the thickness gradient; Decomposing the reflected light intensity and phase difference data, calculating the spatial frequency components of each region, and obtaining a three-dimensional spectral data set containing thickness distribution characteristics; Dividing the three-dimensional spectral data set into a plurality of discrete regions according to the thickness distribution characteristics, calculating the center coordinates and boundary curvature of each region, and obtaining a spatial annotation map; Calculating the best focusing position of the laser at each point on the space annotation map, and obtaining the laser power based on the best focusing position, and setting it as the preset power; According to the preset power, the gradient thickness substrate is longitudinally etched by using ultraviolet laser equipment to form a V-shaped groove on the surface of the gradient thickness substrate.

[0010] Furthermore, the step of electrospinning and heat treating the gradient spacing template to obtain a substrate containing a dynamic thermal conductive network comprises: The gradient spacing template is subjected to electrospinning deposition treatment, and a formamide solution containing boron nitride nanosheets and polyvinylidene fluoride is sprayed onto the template surface at a flow rate of 0.5 mL / h to form a nanofiber layer with a thickness of about 20 μm; Based on a pulse electric field, liquid metal is migrated along the V-shaped groove and infiltrated into the bottom of the nanofiber layer, and low-temperature preheating is performed to obtain a pre-cured thermal conductive substrate; The pre-cured thermal conductive substrate is subjected to high temperature heat treatment to form a local melting connection between the boron nitride nanosheets and the liquid metal in the micropores to construct a three-dimensional dynamic thermal conductive network, wherein the heating temperature is 680-700° C. and the heating time is 10-15 minutes; A siloxane suspension containing aluminum oxide nanoparticles is injected into the surface of the substrate of the three-dimensional dynamic heat-conducting network under vacuum conditions to obtain a substrate containing a dynamic heat-conducting network.

[0011] Furthermore, the step of subjecting the substrate containing the dynamic heat conductive network to a pre-pressing treatment of the conductive layer to obtain a pre-assembled plate comprises: Placing the substrate containing the dynamic heat conductive network in a plasma treatment chamber, and performing surface plasma activation treatment using a mixed gas of argon and oxygen to form an activation layer rich in hydroxyl and carboxyl groups on the surface, thereby obtaining an activated substrate; Depositing graphene-modified copper foil on the surface of the activation layer by chemical vapor deposition to form a diamond carbon film to obtain a composite conductive film; The two composite conductive films are placed on the upper and lower sides of the activated substrate respectively, put into a pre-alignment fixture, and pre-pressed at 120° C. for 10 minutes to make the central area fit together and form a 5-10 μm microgap at the edge to obtain the pre-assembled plate.

[0012] Furthermore, the step of subjecting the preassembled panels to dynamic pressing in stages to obtain a formed circuit board comprises: The preassembled sheet is placed in a pre-pressing machine, and the pre-assembled sheet is pre-pressed by a step-by-step temperature rise pre-pressing process to obtain a reinforced pre-assembled sheet, wherein the first stage of the step-by-step temperature rise pre-pressing process is a temperature of 200°C, a central area pressure of 10MPa, and an edge pressure of 5MPa, which lasts for 20 minutes, so that the central area is completely sealed and the edge gap is compressed to 2μm; the second stage is a temperature of 280°C, and the pressure of the entire area is increased to 15MPa, which is maintained for 30 minutes; The surface of the reinforced pre-assembled plate is flattened by mechanical polishing equipment to obtain the molded circuit board with a surface roughness of 100 Å, wherein the polishing liquid is an acidic suspension containing aluminum oxide particles.

[0013] Furthermore, the step of performing surface spraying and deposition treatment on the molded circuit board to obtain the high thermal conductivity circuit board includes: The aqueous solution containing zinc oxide nanorods and microcapsules is uniformly coated on the surface of the molded circuit board by ultrasonic spraying technology, the spraying pressure is 0.2MPa, the coating thickness is controlled at 15μm, and thermally cured at 90°C for 20 minutes to obtain a primary coating substrate; Placing the primary coating substrate in an atomic layer deposition device, using titanium tetrachloride and ammonia as precursors, and depositing a titanium nitride protective film under vacuum conditions to obtain a protective layer substrate; The protective layer substrate was placed in an annealing furnace in a nitrogen atmosphere, heated to 300° C. at a heating rate of 5° C. / min, maintained for 30 minutes, and then cooled to room temperature at a cooling rate of 3° C. / min to obtain the high thermal conductivity circuit board.

[0014] The present application also discloses a high thermal conductivity circuit board, which is manufactured by the pressing and preparing method of the high thermal conductivity circuit board as described in any one of the above items.

[0015] Compared with the prior art, this application has the following beneficial effects: The pressing and preparing method of the high thermal conductivity circuit board of the present application can obtain an adaptive thermally conductive substrate by dispersing and solidifying a liquid metal and fiber mixture, forming a relatively uniform heat conduction network, and using gradient deposition and etching processing technology to form a gradient spacing template on the surface of the substrate, effectively optimizing the heat flow path, so that the heat flow can be efficiently transmitted along a predetermined path, avoiding the thermal interface effect, and further improving the thermal conductivity. The electrospinning infiltration and heat treatment technology is used to introduce a dynamic thermal conductive network into the substrate, and the conductivity of the circuit board is improved by pre-pressing the conductive layer of the substrate and dynamically pressing it in stages. The heat resistance and oxidation resistance of the molded circuit board are enhanced by surface spraying and deposition treatment, further improving the reliability and long-term stable working ability of the circuit board.

[0016] In summary, the present application solves the problems of poor heat flow path and poor interface bonding in the prior art, and significantly improves the thermal management effect, especially in the field of high-power electronic equipment and integrated circuits. It can significantly improve the reliability and performance of electronic products and meet the market demand for efficient thermal management materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] The structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with this technology. They are not used to limit the conditions under which this application can be implemented, and therefore have no substantive technical significance. Any structural modification, change in proportion or adjustment of size, without affecting the effects and purposes that can be achieved by this application, should still fall within the scope of the technical contents disclosed in this application.

[0019] Figure 1 The figure is a schematic diagram of the overall steps of the pressing preparation method of the high thermal conductivity circuit board; Figure 2 A schematic diagram of the steps of an embodiment of a method for laminating a high thermal conductivity circuit board; Figure 3 The figure is a schematic diagram of the steps of another embodiment of a method for preparing a high thermal conductivity circuit board by pressing. DETAILED DESCRIPTION

[0020] In order to make the purpose, features, and advantages of the invention of this application more obvious and easy to understand, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the embodiments described below are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0021] In the description of the present application, it should be understood that the terms "upper", "lower", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. It should be noted that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally arranged component at the same time.

[0022] The technical solution of the present application is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0023] refer to Figures 1 to 3 The present application provides a method for laminating a high thermal conductivity circuit board, comprising: S1: Dispersing and solidifying the liquid metal gallium-indium alloy and the fiber mixture in an inert argon atmosphere, and fusing with the matrix to obtain an adaptive thermal conductive substrate; In step S1, the liquid metal has a high thermal conductivity, and gallium (Ga), aluminum (Al) and tin (Sn) can be selected. In the liquid state, it can work together with the fiber mixture to form a composite material with high thermal conductivity. Liquid metal can fill the gaps in the fiber, forming a more continuous thermal conductive network structure and improving the efficiency of heat conduction. The liquid metal and the fiber mixture are mixed in a certain proportion, which can be achieved by mechanical stirring or ultrasonic dispersion technology to ensure that the liquid metal and the fiber are evenly mixed to avoid agglomeration of the material during the curing process. In order to further improve the thermal conductivity of the composite material, some surfactants or additives can be added to improve the interface bonding between the liquid metal and the fiber, promote the formation of an interpenetrating network structure between the metal and the fiber, and perform the curing treatment under appropriate temperature and pressure conditions. After the curing process is completed, the liquid metal and the fiber mixture will form an adaptive thermal conductive substrate with excellent thermal conductivity and, to a certain extent, adjustability and adaptability. The characteristic of adaptive thermal conductive substrate is that its thermal conductivity can be appropriately adjusted according to different usage conditions. For example, in some high-power application scenarios, the thermal conductivity can be further improved by changing the content of liquid metal or the distribution of fibers. This adaptive characteristic makes the material widely used in various electronic devices with high heat loads, especially in the packaging of high-power electronic devices and integrated circuits.

[0024] S2: performing gradient deposition and etching on the adaptive thermal conductive substrate to obtain a gradient spacing template; In step S2, gradient deposition refers to depositing materials layer by layer at different densities or thicknesses to form regions with different physical properties. In this embodiment, the gradient deposition process can effectively adjust the thermal conductivity of the substrate. By controlling the deposition rate, the type of deposition material, and the order of deposition, different regions of the circuit board can show gradient differences in thermal conductivity, so that when the heat flow flows in the circuit board, it can be selectively accelerated or slowed down according to demand. Etching treatment is to remove the deposited material locally, refine the structure of the circuit board, and form a microstructure with a gradient spacing, which can significantly improve the conduction path of the heat flow. Etching treatment can be carried out by dry etching or wet etching, and the specific selection depends on the characteristics of the deposited material and the final required structural accuracy. The morphology of the heat conductive material can be controlled by etching treatment, so that the heat flow can be transmitted along the optimized path, thereby improving the overall thermal conductivity of the circuit board. For example, gradient deposition can be carried out by depositing metal or composite materials on the surface of the substrate layer by layer at a certain thickness by laser melting deposition or electron beam deposition. The deposited materials may include metals, ceramics, or high thermal conductivity composite materials. Subsequently, an etching process is used to remove part of the deposited material to form a microscopic, hierarchical thermal conductive network structure. This template with gradient spacing optimizes the heat flow path, can provide better thermal management between the heat source and the heat sink, and ensure that heat can quickly and effectively diffuse from the high-temperature area to the low-temperature area. Through the combination of gradient deposition and etching, the microstructure formed on the surface of the circuit board can maintain thermal conductivity while also enhancing the mechanical strength and stability of the substrate.

[0025] S3: electrospinning and heat treating the gradient spacing template to obtain a substrate containing a dynamic thermal conductive network; In step S3, the electrospinning infiltration treatment is to use electrospinning technology to infiltrate the material into the structure of the gradient spacing template, and to infiltrate the thermal conductive material or high thermal conductivity fiber into the microstructure of the template to form a network-like thermal conduction channel, thereby enhancing the thermal conduction efficiency of the circuit board during operation, thereby ensuring that the heat can be rapidly diffused in high-power usage scenarios, and avoiding overheating of the equipment caused by heat accumulation. The electrospinning technology forms fine fibers by stretching a polymer solution or a molten material under a high electric field, and these fibers can present a high specific surface area and microstructure characteristics. In this step, the material of the electrospinning process can be a metal oxide, a conductive polymer or a metal fiber with good thermal conductivity. When these fibers are electrospun, they will be infiltrated into the gradient spacing template to form a thermal conduction network structure, which can provide a highly optimized thermal conduction channel in the substrate, ensuring that heat can be rapidly diffused from the heating area to other parts of the circuit board. The electrospinning infiltration process controls the intensity of the electric field, the stretching speed of the fiber, the viscosity of the material, and the depth of penetration, so that the thermal conductive fiber can be evenly and effectively covered in each tiny channel of the template, thereby optimizing the efficiency of the thermal conduction network. For example, by adjusting the intensity of the electric field, the fineness of the fiber can be controlled; and by changing the viscosity of the solution, the arrangement of the fibers can be adjusted, thereby further optimizing their thermal conductivity. After the electrospinning infiltration is completed, the infiltrated material is solidified or enhanced to form a stable thermal conductive network structure. The conditions of the heat treatment (such as temperature, time, atmosphere, etc.) are optimized according to the characteristics of the material used. For example, for metal oxides or highly thermally conductive polymers, heat treatment can promote the crystal growth of the material or improve the thermal conductivity of the material, thereby enhancing the overall thermal conductivity of the substrate.

[0026] S4: pre-pressing the conductive layer of the substrate containing the dynamic heat conductive network to obtain a pre-assembled plate; In step S4, the dielectric properties of the circuit board can be enhanced by pre-pressing the conductive layer. The pre-pressing of the conductive layer is to add a conductive material to the surface of the substrate, and to physically or chemically combine it with the surface of the substrate by means of pressurization, heating, etc., to form a strong conductive layer. The conductive layer can be selected from metal materials (such as copper, silver, etc.) or conductive polymers. Metal materials are usually deposited on the surface of the substrate by sputtering, evaporation or electroplating, while conductive polymers can be processed by coating or spraying. The deposition and pressing of these conductive materials can ensure that a uniform, stable and highly conductive conductive layer is formed on the surface of the circuit board. Taking copper as an example, in step S4, the copper layer can be evenly plated on the surface of the substrate that has been treated with a dynamic thermal conductive network by an electroplating process, and can be firmly combined with the surface of the substrate to form a stable conductive channel. During the electroplating process, the deposition rate and deposition thickness of copper are controlled to ensure the uniformity and integrity of the conductive layer. In addition, after electroplating, a heating treatment can be performed to further promote the bonding force between the copper layer and the substrate, making the conductive layer more stable. The pre-pressing treatment can tightly bond the conductive layer to various parts of the substrate, reducing the interface separation or interlayer detachment problems that may occur due to thermal expansion or external force.

[0027] S5: Performing dynamic pressing processing on the pre-assembled panels in stages to obtain a formed circuit board; In step S5, a stable conductive layer has been formed on the surface of the pre-assembled sheet, and the sheet is pressed step by step through multiple stages. Different parameters (such as pressure, temperature, etc.) are controlled in each stage, so that the sheet can be uniformly compressed and heat-treated during the entire pressing process, optimize the bonding between the conductive layer and the substrate, and ensure that the layers can be firmly bonded without defects such as delamination, voids or bubbles. At the same time, by controlling the pressing conditions in stages, stress concentration and unevenness can be effectively avoided, ensuring that the circuit board still maintains high thermal conductivity and mechanical strength after pressing. In actual operation, the staged dynamic pressing may include low-pressure and low-temperature treatment in the initial stage. The purpose of this stage is to make the pre-assembled sheet flat and docked at low temperature and ensure the initial bonding between the various layers. As the pressing progresses, the temperature and pressure gradually increase and enter the medium-pressure stage. At this time, the control of temperature and pressure is more critical, because too high temperature and pressure may cause damage to the conductive layer or substrate, while too low temperature cannot achieve sufficient bonding force. Finally, in the final stage of pressing, the conductive layer and the substrate are completely bonded through concentrated treatment of high temperature and high pressure to form the final molded circuit board. This process needs to ensure uniform distribution of heat treatment and pressure to avoid damage to the circuit board or uneven performance due to local overheating or overpressure.

[0028] S6: performing surface spraying and deposition treatment on the molded circuit board to obtain the high thermal conductivity circuit board.

[0029] In step S6, by spraying and depositing on the surface of the circuit board, its heat conduction efficiency can be effectively improved, and functional failure caused by overheating of the circuit board in a high temperature environment can be prevented. The surface spraying treatment mainly forms a uniform coating by spraying liquid coating or powder material on the surface of the circuit board. These coatings have high thermal conductivity and can effectively improve the thermal conductivity of the circuit board. In actual operation, the material can include metal-based coatings, such as silver, copper coatings, or polymer coatings containing high thermal conductivity fillers. These coatings can quickly transfer heat from the circuit to other parts of the circuit board when high-power current flows through the circuit board to prevent local overheating of the circuit board. In addition, the spraying process can adjust the thickness, uniformity and adhesion of the coating according to demand, ensuring that the coating can be firmly attached to the surface of the circuit board and will not fall off or crack due to long-term use. Surface deposition treatment is to deposit a thin layer of metal or non-metallic material on the surface of the circuit board through physical vapor deposition (PVD), chemical vapor deposition (CVD) and other technologies, which can increase the conductivity of the circuit board and improve its thermal conduction efficiency. Through these deposition processes, a uniform and solid thermal conductive coating can be formed on the surface of the circuit board, thereby improving the heat dissipation capacity of the circuit board and ensuring that it can still work stably in a high temperature environment.

[0030] In one embodiment, reference Figure 2 The step of dispersing and solidifying the liquid metal gallium-indium alloy and the fiber mixture in an inert argon atmosphere and fusing them with the matrix to obtain an adaptive thermal conductive substrate comprises: S21: mixing a liquid metal gallium-indium alloy and a hydroxylated carbon fiber in a mass ratio of 1:3 to form a mixture, mechanically stirring the mixture at 500 rpm for 10 to 20 minutes in an inert argon atmosphere and simultaneously applying low-frequency ultrasonic treatment to obtain a uniform suspension, wherein the molar mass ratio of gallium to indium in the liquid metal gallium-indium alloy is 4 to 5:1; S22: adding the uniform suspension to a mixed solution of a polyimide precursor solution and graphene oxide, and treating under ultrasonic conditions to obtain a composite precursor solution, wherein the mass ratio of the uniform suspension to the mixed solution is 1:5; S23: passing the composite precursor liquid into a microfluidic channel for layered shearing treatment, wherein the width of the microfluidic channel is 50 μm and the flow rate is 0.1 mL / min, and applying an alternating electric field in the channel to obtain a directional primary liquid; S24: pouring the oriented primary liquid into a mold, and pre-curing in a vacuum oven at 100° C. for 40 minutes to obtain a primary cured substrate; S25: performing an orientation treatment on the initially solidified substrate in a uniform magnetic field, and cooling the substrate to room temperature at a rate of 5° C. / min to obtain an oriented substrate, wherein the direction of the magnetic field is parallel to the length direction of the fibers; S26: performing heat pressing treatment on the oriented substrate in a nitrogen atmosphere to obtain the adaptive thermally conductive substrate.

[0031] In the above embodiment, a liquid metal gallium-indium alloy is used, and the molar mass ratio of gallium to indium is 4 to 5:1. The gallium-indium alloy is liquid at room temperature and has excellent thermal conductivity, which can effectively improve the thermal conductivity of the composite material. The liquid metal and the hydroxylated carbon fiber are mixed at a mass ratio of 1:3. The length of the hydroxylated carbon fiber is 50 μm, and hydroxylation treatment is used to enhance the hydrophilicity and reactivity of the carbon fiber surface, thereby improving its bonding with the metal alloy. In this step, the mixture is carried out in an inert atmosphere (such as argon) to avoid oxidation reactions. In this environment, mechanical stirring is performed at a speed of 500 rpm, and low-frequency ultrasonic treatment is applied for 10 to 20 minutes. The role of ultrasonic treatment is to effectively break the agglomeration of carbon fibers through the vibration of sound waves and the rupture of tiny bubbles, and promote the uniform dispersion of liquid metal in the fibers, thereby forming a stable uniform suspension. The uniform suspension was mixed with a polyimide (PI) precursor solution. The polyimide precursor has excellent thermal stability and good mechanical properties. On this basis, graphene oxide (GO) was added as a dispersant. The role of graphene oxide is to improve the dispersibility of the solution and enhance the thermal conductivity and mechanical strength of the composite material. The mass ratio of the uniform suspension to the polyimide solution and the graphene oxide mixture is 1:5. In order to ensure that these components are evenly mixed, the mixture is treated in an ultrasonic environment, using an ultrasonic treatment with a frequency of 40kHz and a power of 200W for 30 minutes. The role of ultrasound is to further promote the full mixing of the components, avoid stratification and inhomogeneity, and thus improve the uniformity and performance of the composite liquid. The obtained composite precursor liquid was injected into the microfluidic channel for layered shearing treatment. Microfluidic technology can accurately control the flow state of the fluid and realize the orderly arrangement of the components in the tiny channel. In this process, the width of the microfluidic channel was set to 50μm and the flow rate was 0.1mL / min. Under this condition, each component in the liquid will be subjected to a certain shear force during the flow, prompting it to arrange in a specific way. An alternating electric field is applied in the channel. The electric field is used to further align the liquid metal and carbon fiber in a specific direction to form an oriented primary liquid. The guiding effect of the electric field can promote the oriented arrangement of fibers and metal particles, thereby forming a more effective heat conduction channel in the subsequent substrate. The oriented primary liquid is poured into the mold and pre-cured in a vacuum oven at 100°C for 40 minutes. The vacuum environment at low temperature allows the material to be formed without being fully cured, maintaining a high fluidity and avoiding the generation of bubbles, ensuring the density and surface smoothness of the substrate. After pre-curing, the material obtains a preliminary structural form, forming a substrate with a thickness of 0.8 mm, and is oriented using a magnetic field. Through the action of the magnetic field, the liquid metal and carbon fiber are arranged in a certain direction. The direction of the magnetic field is parallel to the length direction of the fiber, promoting the conduction of heat along the fiber direction, thereby forming an efficient heat conduction channel.The magnetic field intensity is set to 0.5T, which can effectively induce the directional arrangement of liquid metal and carbon fiber in the composite material. After the treatment is completed, the material is cooled to room temperature at a rate of 5℃ / min to ensure that there will be no excessive thermal stress in the cooling process, avoid deformation of the material during the cooling process, and perform hot pressing on the oriented substrate to further enhance its thermal conductivity and mechanical strength. The hot pressing treatment is carried out in a nitrogen atmosphere to avoid the occurrence of oxidation reactions. Through hot pressing treatment, the fibers, metals and polyimide in the substrate form a tighter bond, which improves the overall thermal conductivity and mechanical stability of the material. The thermal conductivity of the adaptive thermal conductive substrate at different temperatures has the characteristic of adaptive adjustment. For example, at 25℃, the thermal conductivity of the substrate is 10W / (m·K), and at 150℃, the thermal conductivity can be increased to 18W / (m·K). This feature makes the substrate more temperature adaptable than the existing static filler substrate, and can maintain good thermal conductivity under different operating temperature conditions, thereby meeting the heat dissipation requirements of high-performance electronic devices.

[0032] In one embodiment, the step of performing gradient deposition and etching on the adaptive thermal conductive substrate to obtain a gradient spacing template includes: Applying a silica gel layer of nano-alumina particles to the outer wall of the adaptive thermal conductive substrate to form a primary positioning substrate; Obtaining the surface characteristics of the primary positioning substrate, injecting an ethanol solution of polydimethylsiloxane and nano-carbon fiber with a preset concentration according to the surface characteristics for deposition treatment, forming a gradient layer with a thickness decreasing from 50 μm in the center to 5 μm at the edge, and obtaining a gradient thickness substrate; According to the distribution of the gradient thickness substrate, an ultraviolet laser with a preset power is used to etch the substrate longitudinally to form a V-shaped groove, thereby obtaining a periodic groove substrate with a gradient spacing, wherein the groove spacing increases from 50 μm at the center to 100 μm at the edge; Based on the vapor deposition technology, a suspension containing zinc oxide nanoparticles is injected into the surface of the periodic groove substrate to make the nanoparticles gradiently distributed along the groove depth direction to obtain the gradient spacing template, wherein the deposition pressure is 0.03~0.05MPa and the filling time is 10 minutes.

[0033] In the above embodiment, a silica gel layer of nano-alumina particles is used for coating. The nano-alumina particles have good thermal conductivity, and when used as a coating in silica gel, they can improve the adhesion and stability of the coating to form a primary positioning substrate. An ethanol solution of polydimethylsiloxane (PDMS) and nano-carbon fibers is injected layer by layer on the surface of the substrate to form a gradient layer with a thickness gradually decreasing from 50 μm in the center to 5 μm at the edge. In order to achieve this effect, microfluidic technology is used to inject this solution layer by layer through a microchannel with a width of 20 μm, ensuring the precise control of the solution, forming a thickness change of the gradient layer, so that the thickness of the gradient layer transitions evenly from the center to the edge, and maintaining a good deposition effect in the process. After the gradient layer is deposited, the deposited substrate is placed in a high temperature environment and cured at 150°C for 20 minutes. The polydimethylsiloxane is cross-linked to form a solid network structure, and the nano-carbon fibers are fixed in the substrate, thereby enhancing the mechanical properties and thermal conductivity of the substrate. According to the distribution of the gradient thickness substrate, an ultraviolet laser is used for etching, and a part of the material on the surface of the substrate is removed by the strong energy of the laser. In this embodiment, the wavelength of the laser is set to 266nm, the power is 5W, and the laser etches longitudinally along the substrate to form a V-shaped groove, the depth of the V-shaped groove is 10μm, and the angle is 30°. During the etching process, the groove spacing gradually increases from 50μm in the center of the substrate to 100μm at the edge. The periodic structure of the groove enables the substrate to form an orderly heat conduction channel during the heat conduction process, effectively enhancing the heat conduction efficiency, and the design of this periodic groove helps to optimize the heat flow path of the substrate and improve the overall heat dissipation performance. A suspension containing zinc oxide nanoparticles is injected into the surface of the substrate. Through vapor deposition, the zinc oxide nanoparticles gradually form a gradient distribution along the groove depth direction. The deposition pressure is controlled between 0.03 and 0.05MPa, and the filling time is 10 minutes, so that the zinc oxide particles form a gradual structure in the groove depth direction, thereby further improving the thermal conductivity and surface stability of the substrate.

[0034] In one embodiment, the step of etching longitudinally along the substrate using an ultraviolet laser of preset power to form a V-shaped groove according to the distribution of the gradient thickness substrate further includes: Scanning longitudinally along the gradient thickness substrate using a laser scanning device to collect reflected light intensity and phase difference data corresponding to the thickness gradient; Decomposing the reflected light intensity and phase difference data, calculating the spatial frequency components of each region, and obtaining a three-dimensional spectral data set containing thickness distribution characteristics; Dividing the three-dimensional spectral data set into a plurality of discrete regions according to the thickness distribution characteristics, calculating the center coordinates and boundary curvature of each region, and obtaining a spatial annotation map; Calculating the best focusing position of the laser at each point on the space annotation map, and obtaining the laser power based on the best focusing position, and setting it as the preset power; According to the preset power, the gradient thickness substrate is longitudinally etched by using ultraviolet laser equipment to form a V-shaped groove on the surface of the gradient thickness substrate.

[0035] In this embodiment, the laser scanning device is controlled to scan along the longitudinal direction of the gradient thickness substrate, and the reflected light intensity and phase difference data are collected by the sensor. The reflected light intensity and phase difference reflect the surface characteristics of the substrate, especially the change of the surface thickness. Since the thickness of the substrate changes in a gradient, the collection of these optical parameters can reflect the thickness information of different regions in real time, and the collected reflected light intensity and phase difference data will be decomposed and processed. By decomposing the data, the spatial frequency components of each region can be extracted. These components contain the details of the surface thickness distribution. The calculation of the spatial frequency components can help analyze the reflection characteristics of different regions of the substrate under the action of light, so as to obtain the thickness change of each region. This process is completed by technical means such as Fourier transform of data, which can extract valuable information from complex data, form a three-dimensional spectral data set, and divide it into multiple discrete regions according to the thickness distribution characteristics. The surface of the entire substrate is divided into different regions, so that each region can be processed separately, thereby achieving more accurate etching. After the division, the center coordinates and boundary curvature of each area are calculated, such as the center position and shape of each area, to generate a space annotation map. The role of the space annotation map is to mark the key feature points of each area, including the thinnest or thickest places, and calculate the best focus position of the laser in each area of ​​the space annotation map. Because the thickness and curvature of different areas are different, the focus position of the laser must be adjusted according to these changes to ensure that the laser can effectively focus on the best position of each area, thereby improving the accuracy and efficiency of etching, and adjusting the power of the laser based on these positions. In actual operation, the setting of the laser power is precisely controlled according to the required etching depth and the optical properties of the substrate. By adjusting the laser power, the depth control of different areas can be achieved, thereby ensuring that the depth and shape of the V-groove meet expectations. According to the preset power set, the gradient thickness substrate is longitudinally etched using ultraviolet laser equipment to form a V-groove on the surface of the substrate.

[0036] In another embodiment, the calculation expression of the above steps in the computer device is: ; in, is the power of the UV laser, which represents the laser power at each position (x, y coordinates) on the substrate surface; Ω is the integration area, which represents the entire scanning area on the substrate surface; is the optical property function of the substrate at position x, y, representing the reflectivity and absorptivity of the substrate surface; Reflected light intensity and phase difference Fourier transform of the data to extract the spatial frequency components of the surface; is the thickness distribution function, the thickness distribution of the substrate Through Fourier transform, we get, and the region partition function Combined, it is used to divide the surface into regions; Adjust the function for laser focus to ensure optimal focus of the laser in each area; It is an area element per unit area on the surface, representing a tiny area on the surface of the substrate.

[0037] In one embodiment, the step of electrospinning and heat treating the gradient spacing template to obtain a substrate containing a dynamic thermal conductive network comprises: The gradient spacing template is subjected to electrospinning deposition treatment, and a formamide solution containing boron nitride nanosheets and polyvinylidene fluoride is sprayed onto the template surface at a flow rate of 0.5 mL / h to form a nanofiber layer with a thickness of about 20 μm; Based on a pulse electric field, liquid metal is migrated along the V-shaped groove and infiltrated into the bottom of the nanofiber layer, and low-temperature preheating is performed to obtain a pre-cured thermal conductive substrate; The pre-cured thermal conductive substrate is subjected to high temperature heat treatment to form a local melting connection between the boron nitride nanosheets and the liquid metal in the micropores to construct a three-dimensional dynamic thermal conductive network, wherein the heating temperature is 680-700° C. and the heating time is 10-15 minutes; A siloxane suspension containing aluminum oxide nanoparticles is injected into the surface of the substrate of the three-dimensional dynamic heat-conducting network under vacuum conditions to obtain a substrate containing a dynamic heat-conducting network.

[0038] In this embodiment, a solution containing 10wt% boron nitride nanosheets (BNNS) and polyvinylidene fluoride (PVDF) (solvent is DMF) is sprayed onto the surface of the gradient spacing template at a rate of 0.5mL / h by electrospinning deposition, forming a nanofiber layer of about 20μm thick. Electrospinning technology is a process that uses electric field to drive polymer solution or melt to form fibers, which can realize the formation of nanoscale fibers, thereby providing a large surface area for liquid metal penetration. The conditions are electrospinning voltage of 15kV and receiving distance of 10cm. Pulsed electric field technology (intensity of 5kV / cm, frequency of 1Hz) is used to migrate liquid metal along the V-shaped groove on the surface of the gradient template and penetrate into the bottom of the nanofiber layer. The special effect of the pulsed electric field is used to drive the liquid metal to flow in a short time and penetrate into the bottom of the fiber layer, filling the tiny pores of the template, promoting the connection between nanofibers, enhancing the connectivity of the thermal conductive network, and performing low-temperature preheating. The liquid metal penetrates at a lower temperature and initially combines with the surface of the fiber layer. High-temperature hot pressing treatment is carried out in the temperature range of 680~700℃ for 10~15 minutes, so that the boron nitride nanosheets and liquid metal form a local molten connection in the micropores, thereby constructing a three-dimensional dynamic thermal conductive network. At this temperature, the thermal stability of the boron nitride nanosheets is good, and the liquid metal is at a temperature close to its melting point, which can effectively melt and combine with the boron nitride nanosheets to form a three-dimensional network structure. Under vacuum conditions, a siloxane suspension containing aluminum oxide nanoparticles is injected into the surface of the substrate of the three-dimensional dynamic thermal conductive network to form a protective film containing aluminum oxide nanoparticles on the surface, further improving the thermal conductivity and surface stability of the material. Alumina, as a common high thermal conductivity material, can effectively improve the overall thermal conductivity of the substrate, and siloxane can provide better interfacial adhesion to ensure that the aluminum oxide particles can be stably distributed on the surface of the substrate. By injecting in a vacuum environment, the influence of moisture and other impurities in the air on the material properties can be effectively avoided, thereby ensuring the high quality of the final product. This embodiment realizes an adaptive heat conduction path under heat load through the fluidity of liquid metal, and the thermal conductivity is increased to 25W / (m·K), which is different from the existing static filler network and provides a high-performance substrate.

[0039] In one embodiment, the step of subjecting the substrate containing the dynamic thermal conductive network to a pre-pressing treatment of the conductive layer to obtain a pre-assembled plate comprises: Placing the substrate containing the dynamic heat conductive network in a plasma treatment chamber, and performing surface plasma activation treatment using a mixed gas of argon and oxygen to form an activation layer rich in hydroxyl and carboxyl groups on the surface, thereby obtaining an activated substrate; Depositing graphene-modified copper foil on the surface of the activation layer by chemical vapor deposition to form a diamond carbon film to obtain a composite conductive film; The two composite conductive films are placed on the upper and lower sides of the activated substrate respectively, put into a pre-alignment fixture, and pre-pressed at 120° C. for 10 minutes to make the central area fit together and form a 5-10 μm microgap at the edge to obtain the pre-assembled plate.

[0040] In this embodiment, the substrate containing the dynamic thermal conductive network is pretreated by surface plasma activation treatment, which is carried out in a plasma treatment chamber and uses a mixed gas of argon and oxygen. The role of plasma activation is to activate the surface of the substrate by high-energy plasma to form an activation layer rich in hydroxyl (-OH) and carboxyl (-COOH) groups, so that the surface of the substrate has a higher surface energy, which can significantly improve the adhesion performance of subsequent materials, especially when coating the conductive layer, it can effectively enhance the adhesion and stability of the conductive film. After completing the surface activation, the graphene-modified copper foil is deposited on the surface of the activated substrate by chemical vapor deposition (CVD). The graphene-modified copper foil is a copper foil modified with graphene, and the graphene content is 2wt%. This modification can improve the thermal conductivity and electrical conductivity of the copper foil. Through chemical vapor deposition technology, a layer of diamond-like carbon film is grown on the surface of the graphene-modified copper foil. The thickness of this film layer is 5μm. The diamond-like carbon film (DLC film) has excellent hardness and wear resistance. The two composite conductive films are placed on the upper and lower sides of the activated substrate respectively and clamped by a pre-alignment fixture. The function of the pre-alignment fixture is to ensure that the conductive film maintains accurate positioning throughout the pre-pressing process to avoid quality problems caused by offset or uneven pressure. The entire assembly is pre-pressed at a temperature of 120°C for 10 minutes. In this process, the temperature of 120°C can ensure that the material undergoes appropriate deformation during the pressing process, so that the central area of ​​the substrate is firmly attached to the conductive film, while the edge area maintains a certain microgap between 5 and 10μm. The preassembled plate obtained through the above steps can effectively conduct the heat generated by the electronic components to the substrate, thereby improving the heat dissipation efficiency and extending the service life of the equipment.

[0041] In one embodiment, the step of performing a staged dynamic pressing process on the pre-assembled panels to obtain a formed circuit board includes: The preassembled sheet is placed in a pre-pressing machine, and the pre-assembled sheet is pre-pressed by a step-by-step temperature rise pre-pressing process to obtain a reinforced pre-assembled sheet, wherein the first stage of the step-by-step temperature rise pre-pressing process is a temperature of 200°C, a central area pressure of 10MPa, and an edge pressure of 5MPa, which lasts for 20 minutes, so that the central area is completely sealed and the edge gap is compressed to 2μm; the second stage is a temperature of 280°C, and the pressure of the entire area is increased to 15MPa, which is maintained for 30 minutes; The surface of the reinforced pre-assembled plate is flattened by mechanical polishing equipment to obtain the molded circuit board with a surface roughness of 100 Å, wherein the polishing liquid is an acidic suspension containing aluminum oxide particles.

[0042] In this embodiment, the preassembled sheet is placed in a pre-pressing machine, and the preassembled sheet is pre-pressed by a step-by-step temperature pre-pressing process. Through precise temperature and pressure control, the preassembled sheet can experience different pressing conditions at different stages to achieve the best fit and performance. In the first stage, the temperature is set to 200°C, and a pressure of 10MPa is applied to the central area of ​​the preassembled sheet, and a pressure of 5MPa is applied to the edge area for 20 minutes. The goal of this stage is to make the central area of ​​the preassembled sheet completely close, and at the same time, the micro-gap in the edge area is compressed to 2μm. At this stage, the effects of heat and pressure work together to gradually tighten the internal structure of the preassembled sheet, ensure good contact between high thermal conductivity materials, and reduce bubbles or gaps caused by insufficient pressure. In the second stage, the temperature is further increased to 280°C, and the pressure of the entire area is increased to 15MPa, and the pressure is maintained for 30 minutes. At this time, the increase in temperature and pressure prompts the liquid metal or other filling materials to migrate in the micro-gaps, further filling the tiny gaps left in the first stage of the lamination process. Through the combined effect of pressure and temperature, the liquid metal can fully fill all the micro-gaps, thereby forming a uniform structure, reducing the problem of poor contact between layers, and optimizing the thermal conductivity of the circuit board. Through this process, the entire pre-assembled board is strengthened, and the pressure distribution between the center and edge areas becomes more uniform, ensuring the balance of the thermal conductivity effect. Further, the interlayer spacing distribution is verified by X-ray tomography technology. The scanning results show that the interlayer spacing in the center area is 0μm and the interlayer spacing in the edge area is 2μm. This gradient heat flow structure helps to optimize the thermal conductivity, effectively disperse and conduct heat, and prevent local overheating. After completing the staged dynamic lamination process, the mechanical polishing equipment is used for flattening. Chemical mechanical polishing (CMP) technology can be selected to achieve the required smoothness and precision of the material surface through the combined action of physics and chemistry. In this embodiment, the polishing liquid uses an acidic suspension containing aluminum oxide particles. These particles act as abrasives during the polishing process, which can effectively remove small surface unevenness and further improve the surface quality of the circuit board. In this process, the aluminum oxide particles physically rub against the material surface, smoothing the surface roughness, so that the final formed circuit board has a smoother surface structure, thereby improving the performance and stability of the circuit board.

[0043] In one embodiment, reference Figure 3 The step of performing surface spraying and deposition treatment on the molded circuit board to obtain the high thermal conductivity circuit board includes: S61: uniformly coating the aqueous solution containing zinc oxide nanorods and microcapsules on the surface of the molded circuit board by ultrasonic spraying technology, with a spraying pressure of 0.2 MPa and a coating thickness controlled at 15 μm, and thermally curing at 90° C. for 20 minutes to obtain a primary coating substrate; S62: placing the primary coating substrate in an atomic layer deposition device, using titanium tetrachloride and ammonia as precursors, and depositing a titanium nitride protective film under vacuum conditions to obtain a protective layer substrate; S63: placing the protective layer substrate in an annealing furnace in a nitrogen atmosphere, heating the temperature to 300° C. at a heating rate of 5° C. / min, maintaining the temperature for 30 minutes, and then cooling the substrate to room temperature at a cooling rate of 3° C. / min to obtain the high thermal conductivity circuit board.

[0044] In this embodiment, an aqueous solution containing zinc oxide nanorods and microcapsules is uniformly coated on the surface of the molded circuit board by ultrasonic spraying technology. Zinc oxide nanorods (ZnO) have good thermal conductivity and an aspect ratio of 10:1, which can effectively enhance the thermal conductivity of the coating. The microcapsules contain liquid gallium (particle size 5μm), which can play a self-repairing function when heated or mechanically damaged. At this time, the spraying pressure is controlled at 0.2MPa to ensure that the coating is uniform without bubbles or irregular coating. The coating thickness after spraying is controlled at 15μm, providing sufficient protective layer thickness without affecting the performance of the circuit board. After the spraying is completed, the molded circuit board is placed in an environment of 90°C for thermal curing, and the curing time is 20 minutes to ensure the firmness and stability of the coating, thereby obtaining a primary coating substrate. The primary coating substrate is placed in an atomic layer deposition (ALD) device for deposition, and titanium tetrachloride (TiCl4) and ammonia (NH3) are used as precursors to deposit a titanium nitride (TiN) protective film under vacuum conditions. Atomic layer deposition technology can ensure the uniformity and precise thickness of the deposited film by controlling the deposition of each layer of the reaction. In this embodiment, the thickness of the deposited titanium nitride film is 30nm. The application of this film can effectively enhance the wear resistance and oxidation resistance of the circuit board surface. The protective layer substrate with the titanium nitride film deposited is placed in an annealing furnace in a nitrogen atmosphere for annealing. The heating rate is 5℃ / min, rising to 300℃ and maintaining for 30 minutes, and then cooling to room temperature at a cooling rate of 3℃ / min. The annealing process can improve the density and stability of the film layer, help the film layer to better combine with the surface of the circuit board, thereby improving the durability and thermal stability of the protective film. During this annealing process, due to the presence of the nitrogen atmosphere, the nitrogen element in the protective film can react with titanium to form a solid titanium nitride structure, further improving the chemical stability of the film layer, and enhancing the thermal stability and weather resistance of the circuit board. In this embodiment, the self-repairing function of the microcapsule enables the circuit board to automatically release liquid gallium, repair surface defects, and restore thermal conductivity when heated or mechanically damaged. For example, when the circuit board is squeezed or scratched by external force, the surface microcapsules break, and the released liquid gallium can fill the surface damage, avoiding the impact of the damage to the thermal conductive layer on the performance of the circuit board and improving the durability of the circuit board. In another embodiment, after 500 thermal cycles (temperature range from -50°C to 200°C), the thermal conductivity of the circuit board is still stable at 30W / (m·K), indicating that the coating can still maintain good thermal conductivity under extreme temperature changes and can continue to work stably. This performance is particularly suitable for high-power applications, such as high-speed electronic components, lasers, etc., so that high thermal conductivity circuit boards can not only work stably under high temperature conditions, but also effectively deal with mechanical damage or surface defects that may occur during long-term use.

[0045] It is worth noting that all the devices described in this application can be realized by existing technologies, the algorithms described are all mature algorithms based on existing technologies, and in the preparation process, the chemicals and conditions used are within the safe range and will not cause harm to operators or the environment. In addition, the prepared high thermal conductivity circuit board has excellent thermal conductivity and self-healing ability, and shows good reliability and stability.

[0046] The present invention also discloses a high thermal conductivity circuit board, which is manufactured by using any of the above-mentioned pressing and preparing methods for the high thermal conductivity circuit board.

[0047] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for laminating a high thermal conductivity circuit board, characterized in that: include: The liquid metal gallium-indium alloy and the fiber mixture are dispersed and solidified in an inert argon atmosphere, and fused with the matrix to obtain an adaptive thermal conductive substrate; Performing gradient deposition and etching on the adaptive thermal conductive substrate to obtain a gradient spacing template; The gradient spacing template is electrospun and heat treated to obtain a substrate containing a dynamic thermal conductive network; The substrate containing the dynamic heat-conducting network is subjected to a conductive layer pre-pressing treatment to obtain a pre-assembled plate; The pre-assembled panels are subjected to dynamic pressing treatment in stages to obtain a formed circuit board; The molded circuit board is subjected to surface spraying and deposition treatment to obtain the high thermal conductivity circuit board.

2. The method for pressing and preparing a high thermal conductivity circuit board according to claim 1, characterized in that: The step of dispersing and solidifying the liquid metal gallium-indium alloy and the fiber mixture in an inert argon atmosphere and fusing the mixture with the matrix to obtain an adaptive thermal conductive substrate comprises: The liquid metal gallium-indium alloy and the hydroxylated carbon fiber are mixed in a mass ratio of 1:3 to form a mixture, and the mixture is mechanically stirred at 500 rpm for 10 to 20 minutes in an inert argon atmosphere while applying low-frequency ultrasonic treatment to obtain a uniform suspension, wherein the molar mass ratio of gallium to indium in the liquid metal gallium-indium alloy is 4 to 5:1; Adding the uniform suspension to a mixed solution of a polyimide precursor solution and graphene oxide, and treating under ultrasonic conditions to obtain a composite precursor solution, wherein the mass ratio of the uniform suspension to the mixed solution is 1:5; Passing the composite precursor liquid into a microfluidic channel for layered shearing treatment, wherein the width of the microfluidic channel is 50 μm and the flow rate is 0.1 mL / min, and applying an alternating electric field in the channel to obtain a directional primary liquid; The oriented primary liquid is poured into a mold, and pre-cured in a vacuum oven at 100° C. for 40 minutes to obtain a primary cured substrate; Orienting the pre-solidified substrate in a uniform magnetic field, and cooling it to room temperature at a rate of 5° C. / min to obtain an oriented substrate, wherein the direction of the magnetic field is parallel to the length direction of the fiber; The oriented substrate is subjected to heat pressing treatment in a nitrogen atmosphere to obtain the adaptive thermally conductive substrate.

3. The method for pressing and preparing a high thermal conductivity circuit board according to claim 1, characterized in that: The step of performing gradient deposition and etching on the adaptive thermal conductive substrate to obtain a gradient spacing template comprises: Applying a silica gel layer of nano-alumina particles to the outer wall of the adaptive thermal conductive substrate to form a primary positioning substrate; Obtaining the surface characteristics of the primary positioning substrate, injecting an ethanol solution of polydimethylsiloxane and nano-carbon fiber with a preset concentration according to the surface characteristics for deposition treatment, forming a gradient layer with a thickness decreasing from 50 μm in the center to 5 μm at the edge, and obtaining a gradient thickness substrate; According to the distribution of the gradient thickness substrate, an ultraviolet laser with a preset power is used to etch the substrate longitudinally to form a V-shaped groove, thereby obtaining a periodic groove substrate with a gradient spacing, wherein the groove spacing increases from 50 μm at the center to 100 μm at the edge; Based on the vapor deposition technology, a suspension containing zinc oxide nanoparticles is injected into the surface of the periodic groove substrate to make the nanoparticles gradiently distributed along the groove depth direction to obtain the gradient spacing template, wherein the deposition pressure is 0.03-0.05 MPa and the filling time is 10 minutes.

4. The method for pressing and preparing a high thermal conductivity circuit board according to claim 3, characterized in that: The step of using a UV laser with a preset power to etch longitudinally along the substrate to form a V-shaped groove according to the distribution of the gradient thickness substrate also includes: Scanning longitudinally along the gradient thickness substrate using a laser scanning device to collect reflected light intensity and phase difference data corresponding to the thickness gradient; Decomposing the reflected light intensity and phase difference data, calculating the spatial frequency components of each region, and obtaining a three-dimensional spectral data set containing thickness distribution characteristics; Dividing the three-dimensional spectral data set into a plurality of discrete regions according to the thickness distribution characteristics, calculating the center coordinates and boundary curvature of each region, and obtaining a spatial annotation map; Calculating the best focusing position of the laser at each point on the space annotation map, and obtaining the laser power based on the best focusing position, and setting it as the preset power; According to the preset power, the gradient thickness substrate is longitudinally etched by using ultraviolet laser equipment to form a V-shaped groove on the surface of the gradient thickness substrate.

5. The method for pressing and preparing a high thermal conductivity circuit board according to claim 3, characterized in that: The step of electrospinning and heat treating the gradient spacing template to obtain a substrate containing a dynamic thermal conductive network comprises: The gradient spacing template is subjected to electrospinning deposition treatment, and a formamide solution containing boron nitride nanosheets and polyvinylidene fluoride is sprayed onto the template surface at a flow rate of 0.5 mL / h to form a nanofiber layer with a thickness of about 20 μm; Based on a pulse electric field, liquid metal is migrated along the V-shaped groove and infiltrated into the bottom of the nanofiber layer, and low-temperature preheating is performed to obtain a pre-cured thermal conductive substrate; The pre-cured thermal conductive substrate is subjected to high temperature heat treatment to form a local melting connection between the boron nitride nanosheets and the liquid metal in the micropores to construct a three-dimensional dynamic thermal conductive network, wherein the heating temperature is 680-700° C. and the heating time is 10-15 minutes; A siloxane suspension containing aluminum oxide nanoparticles is injected into the surface of the substrate of the three-dimensional dynamic heat-conducting network under vacuum conditions to obtain a substrate containing a dynamic heat-conducting network.

6. The method for laminating a high thermal conductivity circuit board according to claim 1, characterized in that: The step of subjecting the substrate containing the dynamic heat conductive network to a conductive layer pre-pressing treatment to obtain a pre-assembled plate comprises: Placing the substrate containing the dynamic heat conductive network in a plasma treatment chamber, and performing surface plasma activation treatment using a mixed gas of argon and oxygen to form an activation layer rich in hydroxyl and carboxyl groups on the surface, thereby obtaining an activated substrate; Depositing graphene-modified copper foil on the surface of the activation layer by chemical vapor deposition to form a diamond carbon film to obtain a composite conductive film; The two composite conductive films are placed on the upper and lower sides of the activated substrate respectively, put into a pre-alignment fixture, and pre-pressed at 120° C. for 10 minutes to make the central area fit together and form a 5-10 μm microgap at the edge to obtain the pre-assembled plate.

7. The method for laminating a high thermal conductivity circuit board according to claim 1, characterized in that: The step of subjecting the pre-assembled panels to dynamic pressing in stages to obtain a formed circuit board comprises: The preassembled sheet is placed in a pre-pressing machine, and the pre-assembled sheet is pre-pressed by a step-by-step temperature rise pre-pressing process to obtain a reinforced pre-assembled sheet, wherein the first stage of the step-by-step temperature rise pre-pressing process is a temperature of 200°C, a central area pressure of 10MPa, and an edge pressure of 5MPa, which lasts for 20 minutes, so that the central area is completely sealed and the edge gap is compressed to 2μm; the second stage is a temperature of 280°C, and the pressure of the entire area is increased to 15MPa, which is maintained for 30 minutes; The surface of the reinforced pre-assembled plate is flattened by mechanical polishing equipment to obtain the molded circuit board with a surface roughness of 100 Å, wherein the polishing liquid is an acidic suspension containing aluminum oxide particles.

8. The method for laminating a high thermal conductivity circuit board according to claim 1, characterized in that: The step of performing surface spraying and deposition treatment on the molded circuit board to obtain the high thermal conductivity circuit board comprises: The aqueous solution containing zinc oxide nanorods and microcapsules is uniformly coated on the surface of the molded circuit board by ultrasonic spraying technology, the spraying pressure is 0.2MPa, the coating thickness is controlled at 15μm, and thermally cured at 90°C for 20 minutes to obtain a primary coating substrate; Placing the primary coating substrate in an atomic layer deposition device, using titanium tetrachloride and ammonia as precursors, and depositing a titanium nitride protective film under vacuum conditions to obtain a protective layer substrate; The protective layer substrate was placed in an annealing furnace in a nitrogen atmosphere, heated to 300° C. at a heating rate of 5° C. / min, maintained for 30 minutes, and then cooled to room temperature at a cooling rate of 3° C. / min to obtain the high thermal conductivity circuit board.

9. A high thermal conductivity circuit board, characterized in that: The circuit board is manufactured by the pressing method for preparing the high thermal conductivity circuit board according to any one of claims 1 to 8.

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