High-performance extreme ultrathin vapor chamber and preparation method thereof

Abstract

The invention discloses a high-performance extreme ultrathin vapor chamber and a preparation method thereof, and relates to the technical field of heat dissipation devices, the high-performance extreme ultrathin vapor chamber comprises an upper cover plate, a lower cover plate, a liquid storage tank, an ultra-infiltration supporting layer, a steam chamber and a phase change working medium; the upper cover plate and the lower cover plate are connected in an attached mode, the super-infiltration supporting layer is located between the inner concave face of the lower cover plate and the inner concave face of the upper cover plate, a plurality of steam cavities are evenly distributed in the super-infiltration supporting layer, and the phase change working medium is borne in the super-infiltration supporting layer. And the area of the inner concave surface of the lower cover plate is further concave to form the liquid storage tank. The invention creatively provides a phase change-infiltration coordinated regulation and control strategy, the high-performance extreme ultrathin vapor chamber with the thickness of only 0.1-0.24 mm is prepared through a highly coupled infiltration-support link, arrangement of a liquid storage pool, excavation of a steam chamber and optimization of key parameters, and the double limits of thickness and performance are broken through.

Description

A high-performance, ultra-thin heat spreader and its preparation method Technical Field

[0001] This application relates to the field of heat dissipation device technology, and in particular to a high-performance ultra-thin heat dissipation plate and its preparation method. Background Technology

[0002] A vapor chamber is a heat dissipation device that uses a liquid working fluid to boil and condense within a sealed negative pressure chamber formed by welding metal substrates. It is widely used in mobile phones, tablets, laptops and other terminal electronic products. However, with the rapid development of mobile communication technology, foldable terminal devices are facing increasingly stringent limitations on heat dissipation space as heat flux density continues to rise, creating an urgent need to develop ultra-thin, high-performance vapor chamber products.

[0003] Conventional ultrathin heat spreaders are all over 0.2mm thick, only suitable for non-foldable devices, and cannot meet the extreme space constraints of foldable products. Currently, leading manufacturers of foldable devices still use traditional graphite heat sinks, whose heat dissipation capacity is orders of magnitude lower than that of VC (Vibration Coil) devices, posing a risk of localized overheating, which seriously affects chip performance and user comfort. In recent years, although some patents have mentioned VC design schemes with a theoretical thickness of less than 0.2 mm, their core ideas have mostly focused on the control of hydrophilic and hydrophobic wettability. For example, patent CN113498295A discloses an ultrathin heat spreader and its preparation method and electronic device. The heat spreader includes a first cover plate and a second cover plate. The first cover plate and the second cover plate are sealed together to form a sealed cavity. The sealed cavity is a negative pressure environment and is provided with capillary structure and cooling medium. The inner surface of the first cover plate and / or the inner surface of the second cover plate and / or the capillary structure includes a hydrophobic structure layer and a hydrophilic structure layer. The hydrophobic structure layer is obtained by etching, deposition or film treatment of the first cover plate and / or the second cover plate and / or the capillary structure, followed by surface hydrophobic treatment.

[0004] Regarding the technologies in the aforementioned patents, the inventors believe that existing technologies rely excessively on surface wettability control while neglecting the matching design of core phase change thermodynamic parameters such as the volume ratio of the storage tank, the optimization of the flow resistance of the steam chamber, and the coordination between the working fluid filling rate and the vacuum degree under ultra-thin limits. Within the extreme confinement of a thickness <0.2 mm, the balance between the flow resistance of boiling steam and the capillary driving force of the condensate is extremely sensitive, and single wettability control is insufficient to solve the systemic bottleneck of gas-liquid two-phase transport. Summary of the Invention

[0005] In order to overcome the shortcomings of existing technologies and break through the limits of thickness and performance, this application provides a high-performance ultra-thin heat spreader and its preparation method.

[0006] This application provides a high-performance, ultra-thin vapor chamber, employing the following technical solution: A high-performance, ultra-thin vapor chamber includes an upper cover plate, a lower cover plate, a liquid storage tank, an ultra-wetting support layer, a vapor chamber, and a phase change working fluid; the upper cover plate and the lower cover plate are bonded together, and skirts are provided around the upper cover plate and the lower cover plate, with the skirts having an inward concave surface and a rat tail at one end; the ultra-wetting support layer is located between the concave surfaces of the lower cover plate and the upper cover plate, and a plurality of vapor chambers are uniformly distributed in the ultra-wetting support layer, with the phase change working fluid supported in the ultra-wetting support layer; the region of the concave surface of the lower cover plate is further concave to form the liquid storage tank, and the liquid storage tank has micro-nano composite structures and interconnected grooves distributed inside, the micro-nano composite structures including micron structures and nano morphologies, the micron structures being micron papillae, micron prisms, or micron frustums, and the nano morphologies being nanoparticles, nanosheets, or nanowires connected to the micron structures.

[0007] Preferably, the thickness of both the upper cover plate and the lower cover plate is 0.05-0.12 mm; the thickness of the concave surface of the upper cover plate is 0.01-0.11 mm, and the thickness of the concave surface of the lower cover plate is 0.03-0.1 mm.

[0008] Preferably, the thickness of the superwetting support layer is 0.06-0.2 mm; the form of the superwetting support layer is metal mesh or metal foam; the material of the superwetting support layer is one of copper, aluminum, titanium, nickel, magnesium, or other metals or their mono- or multi-element alloys, as well as carbon steel and stainless steel.

[0009] Preferably, the depth of the storage tank is 0.02-0.08 mm, the shape and distribution of the storage tank are determined according to the shape and location of the heat source in the actual working conditions, and the coverage area of ​​the storage tank is 1-1.5 times the area of ​​the heat source.

[0010] Preferably, the microstructures are arranged uniformly in rows and columns, with a height of 20-80 μm, a width of 0.02-0.08 mm, and a width of 0.01-1 mm; the spacing between adjacent microstructures is 0.01-1 mm, and the size of the nanomorphology is 50-500 nm.

[0011] Preferably, the steam chamber is a single, array, or biomimetic leaf vein-like microchannel, the steam chamber has a depth of 0.02-0.2 mm, a width of 0.05-5 mm, and a spacing of 0.05-5 mm between adjacent steam chambers.

[0012] Preferably, the phase change working fluid is one of water, fluorinated liquid, Freon, acetone, and ethanol, and the volume ratio of the phase change working fluid is 1 / 6 to 2 / 3 of the total volume of the concave space between the upper cover plate and the lower cover plate.

[0013] This application provides a method for preparing a high-performance ultra-thin vapor chamber, which adopts the following technical solution: A method for preparing a high-performance ultra-thin vapor chamber includes the following steps: Step S1, substrate forming: the upper cover plate, the lower cover plate, and the super-wetting support layer are cut to form target contours, and the upper cover plate and the lower cover plate are stamped or etched to form concave surfaces; Step S2, liquid storage tank micro-carving: the liquid storage tank is carved in the target area of ​​the concave surface of the lower cover plate using a pulsed laser, and the laser spot paths are staggered to form interconnected grooves. The unprocessed part surrounded by the interconnected grooves is a periodic micro-nano composite structure; Step S3, wetting control: the superhydrophilic / subsurface superhydrophobic properties of the concave surface of the upper cover plate, the concave surface of the lower cover plate, the upper surface of the liquid storage tank, and the super-wetting support layer are controlled by dry heat treatment or wet heat treatment, while strengthening the superhydrophilic / subsurface superhydrophobic properties of the upper cover plate, the lower cover plate, the upper surface of the liquid storage tank, and the super-wetting support layer. Secondary nano-morphology is derived; Step S4, vapor chamber excavation: the vapor chamber is directionally engraved inside the superwetting support layer along a preset path using a pulsed laser, and the microchannel parameters of the vapor chamber are precisely adjusted by controlling the in-situ or staggered superposition of the laser spot, while a superhydrophobic boundary layer is spontaneously formed; Step S5, skirt welding: the upper cover plate, the superwetting support layer with the vapor chamber, and the lower cover plate with the liquid storage tank are stacked and aligned in sequence, and the skirt is tightly fitted by brazing or laser welding; Step S6, negative pressure liquid injection sealing: the liquid injection tube is inserted into the reserved hole at the tail of the upper cover plate and the lower cover plate and fixed, the phase change working fluid is injected and vacuum sealed immediately, and then the tail is cut off to complete the closed loop; Step S7, finished product shaping: the uniformity and flatness of the sealing device are adjusted by applying pressure, the residual stress is released, and an ultra-thin heat spreader plate is obtained.

[0014] Preferably, in step S2 or step S4, the pulse width of the laser is one of nanosecond, picosecond, or femtosecond; the wavelength is 193-1064nm; the output power is 20-200W; the pulse frequency is 20Hz-2000kHz; and the moving speed is 1-10000mm / s.

[0015] Preferably, in step S3, the dry heat treatment is performed at a temperature of 100-400℃ for 20 min-72 h, and the gas is air or a hydrogen-nitrogen mixture; the wet heat treatment is performed at a temperature of 50-100℃ for 0.05-48 h.

[0016] In summary, this application includes at least one of the following beneficial technical effects: 1. This invention highly couples the steam transport, capillary drive, and rigid support components in traditional ultrathin VC designs through the ultra-wetting support layer with a steam chamber, maximizing space compression and, together with the upper / lower cover plates, constructing an ultra-thin frame with a total thickness of only 0.1-0.24 mm; 2. This invention, through coupling wetting-support, setting up a liquid storage tank, excavating a steam chamber, and optimizing key parameters, achieves for the first time in an area exceeding [missing information - likely a specific thickness]. The invention achieves stable and uniform thermal imaging cloud maps in the vapor chamber, breaking through the dual limits of thickness and performance. At a power consumption of 3W, the temperature difference between the hot and cold ends of products with a thickness of 0.2-0.24mm is less than 1℃, the temperature difference for products with a thickness of 0.15-0.2mm is less than 5℃, and the temperature difference for products with a thickness of 0.1-0.15mm is less than 9℃. 3. The invention provides a method for preparing a high-performance, ultra-thin vapor chamber, which is simple, technologically mature, and low-cost, suitable for large-scale production. It also enables precise adjustment, with a micron structure resolution of less than 20μm and a nanoscale morphology resolution of less than 50nm. 4. This invention abandons the electrochemical or coating processes commonly used in traditional ultra-thin vapor chambers, maximizing the preservation of the intrinsic framework of the substrate. The resulting interface structure and wetting characteristics are more stable and long-lasting, providing reliable protection for high-intensity phase change cycling in extreme confinement environments. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 is a 3D structural schematic diagram of a high-performance ultra-thin vapor chamber; Figure 2 is a cross-sectional assembly schematic diagram of a high-performance ultra-thin vapor chamber; Figure 3 is a top view of the upper / lower cover plates of a high-performance ultra-thin vapor chamber; Figure 4 is a cross-sectional structural diagram of the liquid storage tank of a high-performance ultra-thin vapor chamber; Figure 5 is a 3D structural schematic diagram of two types of super-wetting support layers in a high-performance ultra-thin vapor chamber; Figure 6 is a top view of different types of steam chamber microchannels in a high-performance ultra-thin vapor chamber; Figure 7 is a flowchart of a preparation method for a high-performance ultra-thin vapor chamber; Figure 8 is an ultra-thin stainless steel... Thermal imaging cloud map of steel heat exchange plate and comparison of temperature difference between hot and cold ends in different thickness ranges; Figure descriptions: 1-Upper cover plate, 11-Upper cover plate skirt, 12-Upper cover plate concave surface, 13-Upper cover plate tail; 2-Lower cover plate, 21-Lower cover plate skirt, 22-Lower cover plate concave surface, 23-Lower cover plate tail; 3-Liquid storage tank, 31-Micro-nano composite structure, 32-Connected groove; 4-Superwetting support layer, 41-Metal mesh, 42-Metal foam; 5-Steam chamber, 51-Single microchannel, 52-Arrayed microchannel, 53-Bionic leaf vein microchannel; 6-Phase change working fluid. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: A high-performance, ultra-thin heat exchanger, as shown in Figure 1, includes an upper cover plate 1, a lower cover plate 2, a liquid storage tank 3, an ultra-wetting support layer 4, a steam chamber 5, and a phase change working fluid 6. The liquid storage tank 3 is disposed inside the lower cover plate 2, and the ultra-wetting support layer 4 is placed between the upper cover plate 1 and the lower cover plate 2. The steam chamber 5 is uniformly distributed in the ultra-wetting support layer 4 with periodic microchannels. The upper cover plate 1 and the lower cover plate 2 are tightly fitted together, forming a sealed system together with the liquid storage tank 3, the ultra-wetting support layer 4, the steam chamber 5, and the phase change working fluid 6, as shown in Figure 2. In this embodiment, the upper cover plate 1 and the lower cover plate 2 are made of the same material, including but not limited to metals such as copper, aluminum, and titanium, or their composite materials or alloys, as well as carbon steel, stainless steel, etc. As shown in Figure 3, the thickness of the upper cover plate 1 and the lower cover plate 2 is 0.05-0.12mm. Upper cover plate skirt 11 and lower cover plate skirt 21 are provided around the perimeter for sealing. The inner surfaces of the upper cover plate skirt 11 and lower cover plate skirt 21 are the upper cover plate concave surface 12 and lower cover plate concave surface 22. The space enclosed by the upper cover plate concave surface 12 and lower cover plate concave surface 22 is used to place the superwetting support layer 4 and to support the phase change working fluid 6. Upper cover plate tail 13 and lower cover plate tail 23 are reserved at one end of the upper cover plate skirt 11 and lower cover plate skirt 21 for liquid injection. The depth of the liquid storage tank 3 is 0.02-0.08mm. The shape and distribution of the liquid storage tank 3 are determined according to the shape and location of the heat source in the actual working conditions. The coverage area is 1-1.5 times the area of ​​the heat source; as shown in Figure 4, the liquid storage tank 3 has superhydrophilic properties, and its interior is distributed with micro-nano composite structures 31 and interconnected grooves 32. The micro-nano composite structures 31 include micron structures and nano morphologies. The micron structures are micron papillae, micron prisms, or micron frustums, and the nano morphologies are nanoparticles, nanosheets, or nanowires connected to the micron structures. The micron structures are uniformly arranged in rows and columns, with a height of 20-80 μm, consistent with the depth of the liquid storage tank 3, and a width of 0.01-1 mm. The spacing between adjacent micron structures is 0.01-1 mm, and the equivalent size of the nano morphologies is 50-500 nm. The superwetting support layer 4 is tightly sandwiched in the concave surface 12 of the upper cover plate. Between the concave surfaces 22 of the lower cover plate, there is a superhydrophilic / subsurface superhydrophobic property, which can accelerate the nucleation and boiling of the phase change working fluid, promote capillary drive of the condensed liquid, and provide sufficient rigid support. It takes the form of metal mesh 41 or metal foam 42, as shown in Figure 5. In this embodiment, the material used for the superwetting support layer is one of the following: copper, aluminum, titanium, nickel, magnesium, or their mono- or multi-element alloys, as well as carbon steel and stainless steel. The thickness of the superwetting support layer 4 is 0.06-0.2 mm. The wire diameter of the metal mesh 41 is 0.03-0.1 mm, the weaving method is plain weave or twill weave, and the mesh count ranges from 50 to 500 mesh. The metal foam 42 is a through-hole type with an average pore size of 0.01-0.1 mm, porosity 50-90%; the steam chamber 5 is a periodically distributed microchannel formed by the concave or hollowed-out superwetting support layer 4, which accelerates the transport of boiling steam by increasing the specific surface area and reducing the flow resistance. It is usually drawn out from above the liquid storage tank 3 and radiates to the outer edge of the superwetting support layer 4; as shown in Figure 6, the steam chamber 5 is a single microchannel 51 or an array of microchannels 52 or a biomimetic leaf vein microchannel 53, with a depth of 0.02-0.2 mm and a width of 0.05-5 mm. The spacing between adjacent steam chambers 5 is 0.05-5 mm; the phase change working fluid used in this embodiment is one of water, fluorinated liquid, Freon, acetone, and ethanol. The volume ratio of the phase change working fluid is 1 / 3 of the total volume of the concave bread sandwich space between the upper cover plate and the lower cover plate. 6-2 / 3; This embodiment also provides ultra-thin heat spreaders made of four typical metal materials, with a total design area of ​​1500mm2. The preparation method is as follows: Step S1, copper, aluminum, stainless steel and titanium alloy sheets are used as upper cover plate 1 and lower cover plate 2 respectively. The concave surface 12 of the upper cover plate with a diameter of 0.01-0.11mm and the concave surface 22 of the lower cover plate with a diameter of 0.03-0.1mm are etched. Copper wire mesh, aluminum foam, stainless steel wire mesh and titanium foam are used as super-wetting support layers 4 respectively. The target contour is cut out. Copper and stainless steel are 50-500 mesh plain weave wire mesh with a wire diameter of 0.03-0.1mm. Aluminum and titanium are through-cell foam with an average pore size of 0.01-0.1mm and a porosity of 50-90%. Step S2, use 365nm ultraviolet light to... A 12mm × 12mm liquid reservoir 3 is etched in the target area of ​​the concave surface 22 of the lower cover plate using a second-pulse laser with a power of 5-15W, a frequency of 50-500Hz, and a movement speed of 100-1000mm / s. This forms an array structure of staggered micron-sized truncated pyramids with a width and spacing of 0.1mm, simultaneously obtaining an initial nano-morphology of 50-100nm. In step S3, after a fixed time of 4h, the copper and stainless steel upper cover plates 1 and 2, the liquid reservoir 3, and the superwetting support layer 4 are treated in 100℃ 5% hydrogen-nitrogen mixed gas and 300℃ air, respectively, to obtain superhydrophilic / subsurface superhydrophobic properties, while also generating secondary nanoparticle morphologies of 100-500nm. The upper cover plates 1 and 2 are made of aluminum and titanium alloy, respectively, at 80℃. The reservoir 3 and the superwetting support layer 4 were hydrothermally treated for 8 h and 24 h respectively to complete the wetting control and obtain 100-500 nm secondary nanosheets and nanowires. In step S4, the superwetting support layer 4 was completely hollowed out using a 1064 nm infrared nanosecond pulse laser to form a steam chamber 5 with an array of 11 microchannels. The power was 60-80 W, the frequency was 20-2000 Hz, the moving speed was 100-1000 mm / s, and the width and the spacing between adjacent microchannels were both 0.1 mm. In steps S5-S7, the upper cover plate 1, the superwetting support layer 4 and the lower cover plate 2 were stacked and aligned in sequence, the sealing skirt was brazed, and 20-100 mg of deionized water was injected as the phase change working fluid 6 under a vacuum of 0.01-1 Pa. The chamber was sealed immediately and then...A series of ultra-thin heat spreaders made of different metal materials can be obtained by shaping under 5-5 MPa pressure for 2 minutes.

[0021] In this embodiment, the water volume is 20 / 30 / 40 / 50 / 60 / 70 / 80 / 90 / 100mg and the vacuum degree is 0.01 / 0.05 / 0.1 / 0.5 / 1Pa. With the temperature difference between the hot and cold ends being less than 5℃ and the flatness tolerance being less than ±0.02mm under a power consumption of 2W as the screening criteria, the minimum thickness of four types of ultra-thin heat sink products, namely copper, aluminum, stainless steel and titanium alloy, can reach 0.12mm, 0.14mm, 0.1mm and 0.1mm respectively. This shows that the product described in this invention can stably achieve "ultra-thin" while maintaining basic heat dissipation performance.

[0022] Example 2 This example provides a series of total design areas exceeding The ultra-thin stainless steel heat spreader is prepared as follows: Step S1, an upper cover concave surface 12 with a diameter of 0.01-0.11 mm and a lower cover concave surface 22 with a diameter of 0.03-0.1 mm are etched on a thin stainless steel sheet. A series of stainless steel wire meshes with a wire diameter of 0.03-0.1 mm and a mesh count of 50-500 are used as the super-wetting support layer 4 to cut out the target contour; Step S2, a 20 mm × 20 mm liquid storage tank 3 with a depth of 0.02-0.08 mm is engraved in the target area of ​​the lower cover concave surface 22 using a 365 nm ultraviolet picosecond pulsed laser. At a power of 20W, a frequency of 50kHz, and a moving speed of 80-800mm / s, a micron-sized frustum array with a width and spacing of 0.25mm is formed, resulting in an initial nano-morphology of 50-100nm. In step S3, heat treatment is performed in air at 240℃ for 8 hours to impart superhydrophilic / superhydrophobic properties to the upper cover plate 1, lower cover plate 2, liquid reservoir 3, and superwetting support layer 4, while simultaneously generating secondary nanoparticle morphologies of 100-500nm. In step S4, a 1064nm infrared nanosecond pulsed laser is used to completely hollow out the superwetting support layer 4, forming a structure with... A biomimetic leaf vein-shaped steam chamber 5 is configured with a power of 20W, a frequency of 50Hz, and a moving speed of 500mm / s. The microchannel width of the steam chamber 5 is 0.05mm. In steps S5-S7, the upper cover plate 1, the ultra-wetting support layer 4, and the lower cover plate 2 are stacked and aligned sequentially. The sealing skirt is brazed, and 120-160mg of water is injected as the phase change working fluid 6 under a vacuum of 0.1-0.5Pa. The chamber is immediately sealed, and shaped under a pressure of 1-2MPa for 3-5 minutes to obtain a series of ultra-thin stainless steel heat spreader plates of different thicknesses. In this embodiment, the thickness of the upper / lower cover plates is... The thickness of the 0.05-0.12mm and the thickness of the super-wetting support layer are 0.06-0.2mm, and the flatness tolerance is less than ±0.01mm as a strict limiting condition. Under continuous heating for 120s at 3W power consumption, the temperature difference between the hot and cold ends of the products with thicknesses of 0.2-0.24mm, 0.15-0.2mm and 0.1-0.15mm were tested. The statistical results were 0.9±0.2℃, 4.8±0.9℃ and 8.7±1.4℃, respectively. This breakthrough in both thickness and performance limits has met the basic heat dissipation requirements of current foldable terminal devices.

[0023] Compared with the prior art, the present invention achieves the following technical effects: The present invention highly couples the steam transmission, capillary drive, and rigid support components in the traditional ultrathin VC design through the ultra-wetting support layer 4 with the steam chamber 5, maximizing space compression. Together with the upper cover plate 1 and the lower cover plate 2, it constructs an ultra-thin frame with a total thickness of only 0.1-0.24 mm. The present invention, through coupling wetting and support, setting up the liquid storage tank 3, excavating the steam chamber 5, and optimizing key parameters, achieves for the first time a frame with an area exceeding [missing information - likely a specific thickness]. This invention achieves stable and uniform thermal imaging cloud maps in a vapor chamber, breaking through the dual limits of thickness and performance. At a power consumption of 3W, the temperature difference between the hot and cold ends of a 0.2-0.24mm thick product is less than 1℃, the temperature difference for a 0.15-0.2mm thick product is less than 5℃, and the temperature difference for a 0.1-0.15mm thick product is less than 9℃. The invention provides a high-performance, ultra-thin vapor chamber preparation method that is simple, technologically mature, and low-cost, suitable for mass production. It also enables precise adjustment, with a micron-level structural resolution of less than 20μm and a nanometer-level morphology resolution of less than 50nm. This invention abandons the electrochemical or coating processes commonly used in traditional ultra-thin vapor chambers, maximizing the preservation of the intrinsic framework of the substrate. The resulting interface structure and wetting characteristics are more stable and long-lasting, providing reliable protection for high-intensity phase change cycling in extreme confinement environments.

[0024] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A high-performance, ultra-thin heat spreader, characterized in that: The system includes an upper cover plate, a lower cover plate, a liquid storage tank, a superwetting support layer, a vapor chamber, and a phase change working fluid. The upper cover plate and the lower cover plate are connected to each other and are provided with skirts around their perimeter. The skirts have an inward concave surface and a rat tail at one end. The superwetting support layer is located between the concave surfaces of the lower cover plate and the upper cover plate. Several vapor chambers are evenly distributed in the superwetting support layer, and the phase change working fluid is supported in the superwetting support layer. The concave area of ​​the lower cover plate is further concave to form the liquid storage tank. The liquid storage tank has micro-nano composite structures and interconnected grooves distributed inside. The micro-nano composite structures include micron structures and nano morphologies. The micron structures are micron papillae, micron prisms, or micron frustums. The nano morphologies are nanoparticles, nanosheets, or nanowires connected to the micron structures.

2. The high-performance ultra-thin heat spreader according to claim 1, characterized in that: The thickness of both the upper cover plate and the lower cover plate is 0.05-0.12 mm; the thickness of the concave surface of the upper cover plate is 0.01-0.11 mm, and the thickness of the concave surface of the lower cover plate is 0.03-0.1 mm.

3. The high-performance ultra-thin heat spreader according to claim 1, characterized in that: The thickness of the superwetting support layer is 0.06-0.2 mm; the form of the superwetting support layer is metal wire mesh or metal foam; the material of the superwetting support layer is one of the following: copper, aluminum, titanium, nickel, magnesium, or other metals or their mono- or multi-element alloys, as well as carbon steel and stainless steel.

4. The high-performance ultra-thin heat spreader according to claim 1, characterized in that: The depth of the storage tank is 0.02-0.08 mm. The shape and distribution of the storage tank are determined according to the shape and location of the heat source in the actual working conditions. The coverage area of ​​the storage tank is 1-1.5 times the area of ​​the heat source.

5. The high-performance ultra-thin heat spreader according to claim 1, characterized in that: The micron-structures are arranged uniformly in rows and columns, with a height of 20-80 μm, a width of 0.02-0.08 mm, and a width of 0.01-1 mm; the spacing between adjacent micron-structures is 0.01-1 mm, and the size of the nanomorphology is 50-500 nm.

6. The high-performance ultra-thin heat spreader according to claim 1, characterized in that: The steam chamber is a single, array, or biomimetic leaf vein-like microchannel. The depth of the steam chamber is 0.02-0.2 mm, the width is 0.05-5 mm, and the spacing between adjacent steam chambers is 0.05-5 mm.

7. The high-performance ultra-thin heat spreader according to claim 1, characterized in that: The phase change working fluid is one of water, fluorinated liquid, Freon, acetone, and ethanol, and the volume ratio of the phase change working fluid is 1 / 6 to 2 / 3 of the total volume of the concave space between the upper cover plate and the lower cover plate.

8. A method for preparing a high-performance ultra-thin heat spreader according to any one of claims 1-7, characterized in that: The process includes the following steps: Step S1, Substrate Forming: Cutting the target contours of the upper cover plate, the lower cover plate, and the superwetting support layer, and stamping or etching concave surfaces on the upper cover plate and the lower cover plate; Step S2, Liquid Storage Pool Micro-carving: Using a pulsed laser, carving the liquid storage pool in the target area of ​​the concave surface of the lower cover plate, and staggering the laser spot paths to form interconnected grooves. The unprocessed portion surrounded by the interconnected grooves is a periodic micro-nano composite structure; Step S3, Wetting Control: Using dry heat treatment or wet heat treatment to control the superhydrophilic / subsurface superhydrophobic properties of the concave surface of the upper cover plate, the concave surface of the lower cover plate, the upper surface of the liquid storage pool, and the superwetting support layer, while enhancing the derived secondary nano-morphology; Step S4, Vapor Chamber Creation: Using a pulsed laser... The light is oriented to carve the vapor chamber inside the superwetting support layer along a preset path, and the microchannel parameters of the vapor chamber are precisely adjusted by controlling the in-situ or staggered superposition of the light spot, while a superhydrophobic boundary layer is spontaneously formed; Step S5, skirt welding: The upper cover plate, the superwetting support layer with the vapor chamber, and the lower cover plate with the liquid storage tank are stacked and aligned in sequence, and the skirt is tightly fitted by brazing or laser welding; Step S6, negative pressure liquid injection sealing: The liquid injection tube is inserted into the reserved hole at the tail of the upper cover plate and the lower cover plate and fixed, the phase change working fluid is injected and vacuum sealed immediately, and then the tail is cut off to complete the closed loop; Step S7, finished product shaping: the uniformity and flatness of the sealing device are adjusted by applying pressure, the residual stress is released, and an ultra-thin heat spreader plate is obtained.

9. The method for preparing a high-performance ultra-thin heat spreader according to claim 8, characterized in that: In step S2 or step S4, the pulse width of the laser is one of nanosecond, picosecond, or femtosecond; the wavelength is 193-1064nm; the output power is 20-200W; the pulse frequency is 20Hz-2000kHz; and the moving speed is 1-10000mm / s.

10. The method for preparing a high-performance ultra-thin heat spreader according to claim 8, characterized in that: In step S3, the dry heat treatment is performed at a temperature of 100-400℃ for 20 min-72 h, using air or a hydrogen-nitrogen mixture; the wet heat treatment is performed at a temperature of 50-100℃ for 0.05-48 h.

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