Chip packaging heat dissipation liquid cooling device with sandwich structure

Abstract

This application discloses a chip package heat dissipation liquid cooling device with a sandwich structure, comprising a heat dissipation base and a chip bonding pad located on the heat dissipation base. The chip bonding pad is a sandwich-structured composite plate with copper layers on its upper and lower surfaces, while the heat dissipation base is a diamond metal composite plate with a sandwich structure. The chip bonding pad is welded to the heat dissipation base. This application replaces the traditional heat dissipation copper base plate with lower thermal conductivity by using a sandwich structure with high thermal conductivity and adjustable thermal expansion coefficient. This effectively improves the heat transfer and system heat dissipation capabilities of the liquid cooling device without increasing the size of the cold plate, while also being a low-cost solution.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a chip packaging heat dissipation liquid cooling device with a sandwich structure. Background Art

[0002] With the accelerated penetration of computing power into various industries and sectors, and the deep integration of the internet, big data, and artificial intelligence with the real economy, the demand for computing power is rapidly increasing, leading to an increase in chip power consumption exceeding kilowatts. The popularity of generative intelligence (AIGC) and breakthroughs in the application of large AI models have led to a rapid increase in GPU shipments. Currently, large AI models heavily utilize GPUs for both training and inference. In addition to NVIDA and AMD, major manufacturers are also developing their own GPU chips. Global GPU shipments are expected to continue to rise, reaching approximately 200 million by 2030, and liquid cooling, as the optimal GPU cooling solution, will also gain popularity.

[0003] In newly added GPU computing centers, the rapid increase in power density poses a significant cooling challenge, making liquid cooling an inevitable choice. Considering factors such as initial investment cost, maintainability, PUE performance, and industry maturity, cold plate and single-phase immersion cooling offer advantages over other liquid cooling technologies and are currently the mainstream solutions in the industry.

[0004] The most common configuration for a liquid cold plate (typically a closed chamber made of heat-conducting metals such as copper and aluminum) currently consists of a cold plate base with heat sinks or other topological heat dissipation structures mounted on top. The cold plate base is placed close to the server's heat-generating components (CPU, GPU, memory, etc.), indirectly transferring heat from these components to the cooling liquid enclosed in the circulating pipes, which then dissipates the heat.

[0005] In recent years, numerous approaches have been proposed to incorporate high-thermal-conductivity diamond-copper composite materials into liquid cooling systems, but these efforts have been limited by the influence of the interface layer. CN119008551A discloses a diamond-metal composite heat sink for liquid cooling. While this material serves as a transitional heat sink, the presence of a heat sink base between the composite and the liquid cooling chamber reduces the heat transfer efficiency of the diamond-metal transitional heat sink, regardless of whether the connection is made by welding or bonding. Summary of the Invention

[0006] In order to overcome the shortcomings of the existing technology, the purpose of this application is to provide a chip packaging heat dissipation liquid cooling device with a sandwich structure to ensure structural stability during the thermal cycle, avoid failure due to thermal stress, and solve the problem of poor heat transfer effect of the heat dissipation liquid cooling device.

[0007] To solve the above problems, the technical solutions adopted in this application are as follows:

[0008] An embodiment of the present application provides a chip packaging heat dissipation liquid cooling device with a sandwich structure, including a heat dissipation base and a chip welding platform located on the heat dissipation base, wherein the chip welding platform is a sandwich structure composite plate with copper layers on the upper and lower surfaces; the chip welding platform is welded to the heat dissipation base.

[0009] As a further preferred solution, the heat dissipation base described in the embodiment of the present application adopts a diamond copper composite plate with a sandwich structure.

[0010] As a further preferred embodiment, the diamond-metal composite plate described in the embodiment of the present application is a composite plate formed by sintering a hexahedral metal shell and at least one diamond-metal composite layer placed in the metal shell; the diamond-metal composite layer includes a metal mesh and diamond particles coated with a coating on the surface, the diamond particles are arranged in the grid of the metal mesh, and the gaps between the grid and the diamond particles are filled with metal powder; the metal atoms in the metal mesh diffuse through the coating to the diamond surface, forming a mixed transition zone.

[0011] As a further preferred solution, the coating described in the embodiment of the present application is a coating formed by one material selected from Ti, Cr, W, V, and Zr, or a composite coating formed by two or more materials; the thickness of the coating is 0.1 to 0.5 μm.

[0012] As a further preferred solution, the metal shell, metal mesh and metal powder described in the embodiment of the present application are made of the same metal material, which is copper or aluminum.

[0013] As a further preferred solution, the diamond metal composite plate described in the embodiment of the present application is a composite plate with a copper layer-diamond sheet-copper layer sandwich structure consisting of diamond sheets located in the middle layer and copper layers located on the upper and lower surfaces of the diamond.

[0014] As a further preferred embodiment, the chip bonding station described in the embodiments of the present application is a composite plate formed by sintering a reinforcing material layer positioned in the middle layer and a copper layer coated on the surface of the reinforcing material layer. Specifically, the reinforcing material layer is one of diamond sheet, alumina ceramic, zirconium oxide reinforced alumina ceramic, aluminum nitride ceramic, or silicon nitride ceramic.

[0015] As a further preferred solution, the upper surface and the lower surface of the reinforcement material layer described in the embodiment of the present application are respectively coated with copper layers, or all six sides of the reinforcement material layer are wrapped with copper layers.

[0016] As a further preferred solution, the thickness of the copper layer in the chip welding station described in the embodiment of the present application is 0.1-2 mm; the thickness of the metal layer on the upper surface of the diamond metal composite plate is 0.1-2 mm, and the thickness of the metal layer on the lower surface is 0.2-3 mm.

[0017] As a further preferred solution, the chip packaging heat dissipation liquid cooling device with a sandwich structure described in the embodiment of the present application also includes a liquid cooling box located at the bottom of the heat dissipation base, and a microchannel structure is provided at the bottom of the heat dissipation base; a cavity for accommodating the microchannel structure is provided on the liquid cooling box.

[0018] As a further preferred solution, the microchannel structure described in the embodiment of the present application is a plurality of fins printed on the bottom of the heat dissipation base by 3D printing, and the 3D printing material is 10-50 μm pure copper powder.

[0019] As a further preferred solution, the height of the fins described in the embodiment of the present application is 2-5 mm; the relationship S / δ between the fin thickness δ and the spacing S is 1.5~2, and the sheet thickness δ is 0.1-0.2 mm.

[0020] As a further preferred solution, the chip welding and the heat dissipation base described in the embodiment of the present application are soldered by brazing, and the solder is one of gold-tin solder, nano silver paste, micron silver paste, nano silver paste, and micron copper paste.

[0021] As a further preferred solution, the chip packaging heat dissipation liquid cooling device with a sandwich structure described in the embodiment of the present application can be used in multiple fields. For example, in the field of high-power laser diodes, it can be used for medical lasers, industrial cutting equipment, etc.; in the field of GaN RF amplifiers, it can be used for 5G base stations, radar systems, etc.; in the field of power electronic modules, it can be used for EV motor control, solar inverters, etc.; in the field of aerospace electronic equipment, it can be used for radar modules, satellite communications, etc.; in the field of high-heat flux density electronic device processing, it can be used for liquid cooling of AI servers, GPU clusters, cloud computing and big data centers, as well as for the manufacture of 5G / 6G base station GaN RF chips, electric vehicle SiC inverter modules and other devices; in the field of high-energy laser systems, it can be used to manufacture fiber laser pump couplers and solid laser crystal heat sinks; in the field of nuclear energy and fusion devices, it can be used to manufacture nuclear fusion reactor divertor target plates, plasma first walls, etc.; in the field of special power and energy equipment, it can be used to manufacture electromagnetic catapult system IGBT modules, high-voltage DC circuit breaker contacts, etc.; in the field of aerospace, it can be used for the beam spot area of ​​the electron focusing system and the periphery of the metal 3D printing laser melting pool; in the field of quantum and superconductivity, it can be used to manufacture superconducting quantum bit microwave resonant cavities and room-temperature superconducting transmission line connectors.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The chip welding station of the chip packaging heat dissipation liquid cooling device with a sandwich structure described in this application adopts a sandwich structure composite plate with copper layers on the upper and lower surfaces. The copper layer provides a good heat conduction path. At the same time, the middle layer can use materials with low thermal expansion coefficients such as diamond and ceramics to ensure structural stability during thermal cycling and avoid failure due to thermal stress.

[0024] 2. In the chip packaging heat dissipation liquid cooling device with a sandwich structure described in the present application, the heat dissipation base further adopts a diamond-metal composite plate with high thermal conductivity. By compounding diamond and metal, the heat dissipation base can quickly transfer the heat generated by the chip to the liquid cooling system. In addition, the diamond-metal composite material and the metal-clad layer with fins are an integrated structure, without the need for welding or bonding, and without the influence of the intermediate interface layer, thereby significantly reducing thermal resistance.

[0025] 3. In the sandwich-structured chip package heat dissipation liquid cooling device described herein, a microchannel structure provided at the bottom of the heat dissipation base increases the heat dissipation area. At the same time, the coolant within the liquid cooling box flows through the microchannels, efficiently removing heat. The microchannel structure design enables more efficient heat exchange between the coolant and the heat dissipation base, improving heat transfer efficiency. A cavity provided in the liquid cooling box accommodates the microchannel structure, ensuring that the coolant completely covers the microchannels, forming good thermal contact. This avoids the air gaps or poor coolant flow that can occur in traditional liquid cooling systems, further improving heat transfer.

[0026] 4. The chip package heat dissipation liquid cooling device with a sandwich structure described in this application enables the coolant to quickly remove heat through the design of the microchannel structure and the liquid cooling box, avoiding the accumulation of heat between the transition heat sink and the liquid cooling box, thereby improving the overall heat dissipation efficiency; the use of the sandwich structure and diamond metal composite plate improves the structural stability and thermal cycle life of the device, ensuring that efficient heat transfer performance can be maintained during long-term use.

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 This is a schematic structural diagram of the chip packaging heat dissipation and liquid cooling device with a sandwich structure described in Example 1.

[0030] Figure 2 This is a disassembled state diagram of the chip packaging heat dissipation liquid cooling device with a sandwich structure described in Example 1 of the present application.

[0031] Figure 3 This is a schematic diagram of the fin structure described in Example 1 of the present application.

[0032] Figure 4 This is a schematic structural diagram of the chip packaging heat dissipation liquid cooling device described in Comparative Example 1.

[0033] Among them, the figures are marked as: 10, heat dissipation base; 20, chip welding platform; 11, surface copper layer; 12, diamond copper composite layer; 13, bottom copper layer; 21, diamond sheet; 22, second copper layer; 30, liquid cooling box; 31, cavity; 40, microchannel structure; 50, TIM layer; 60, heat sink structure. DETAILED DESCRIPTION

[0034] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, 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 described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0035] The term "comprising" and other equivalent descriptions in the description and claims of this application are intended to cover non-exclusive inclusions, including both the contents clearly described in the description and claims and the steps or units that are not described in the description and claims but are inherent in the product, method or structure.

[0036] Embodiments of the present application provide a chip packaging heat dissipation and liquid cooling device with a sandwich structure, comprising a heat dissipation base and a chip bonding station located on the heat dissipation base. The chip bonding station is a sandwich-structured composite plate with copper layers on its upper and lower surfaces, the copper layers on the upper and lower surfaces providing a good heat conduction path. The chip packaging heat dissipation and liquid cooling device described in embodiments of the present application is suitable for the heat dissipation needs of high-power density chips. In some embodiments, the heat dissipation base utilizes a diamond-metal composite plate with a sandwich structure. Diamond is combined with metal to rapidly conduct heat generated by the chip during chip packaging, utilizing the extremely high thermal conductivity of diamond. During chip packaging, heat is quickly transferred to the liquid cooling system, reducing thermal resistance. Furthermore, in some embodiments, a liquid cooling box is provided at the bottom of the heat dissipation base. A microchannel structure is provided at the bottom of the heat dissipation base to increase the heat dissipation area, thereby enhancing heat exchange between the coolant and the heat dissipation base. A cavity is provided on the liquid cooling box to accommodate the microchannel structure. In some embodiments, the chip bonding station is a composite plate formed by sintering a reinforcing material layer located in the middle layer and a copper layer coated on the surface of the reinforcing material layer. The reinforcement layer is made of a highly thermally conductive insulating material. Compared to traditional PCB materials, this material combines high thermal conductivity with excellent insulation. In the composite material, the copper layer is responsible for both electrical conduction and heat dissipation, while the reinforcement material in the middle provides structural support and insulation. The composite material formed with the copper metal not only prevents current leakage but also improves the thermal conductivity of the copper composite material.

[0037] In some embodiments of the present application, both the welding platform and the heat sink can be made of a composite material formed by sintering a hexahedral copper foil shell and at least one diamond-metal composite layer within the copper foil shell. This hexagonal cladding structure forms a dense shell that blocks oxygen and water vapor penetration. The metal-diamond interface has poor wettability, requiring expensive coatings and resulting in high interfacial thermal resistance. The synergistic diffusion between the metal foil shell and the internal metal mesh during sintering can effectively reduce interfacial thermal resistance. Traditional materials are susceptible to thermal stress cracking due to the large difference in the coefficient of thermal expansion (CTE) of diamond-metal composites. The diamond-metal composite layer described in the embodiments of the present application includes a metal mesh and coated diamond particles. The diamond particles are arranged within the mesh of the metal mesh, and the spaces between the mesh and the diamond particles are filled with metal powder. This combination of a metal mesh skeleton and metal powder filling allows for the CTE to be adjusted to closely match that of electronic components such as semiconductor chips. The metal foil shell and metal powder filling lower the sintering temperature, prevent diamond graphitization, reduce energy consumption, and improve yield. In the embodiments of the present application, during the sintering process, metal atoms in the metal mesh diffuse through the coating toward the diamond surface, forming a mixed transition zone. Conventional materials exhibit significant anisotropy in thermal conductivity, making it difficult to meet the requirements for directional heat dissipation. In the embodiments of the present application, the metal foil shell and the internal metal mesh-metal powder form a three-dimensional interpenetrating structure, which can effectively improve the thermal conductivity and isotropy of the composite material. Preferably, the metal shell, metal mesh, and metal powder are made of the same metal material, such as copper or aluminum.

[0038] In the above embodiment, the composite plate formed by sintering the hexahedral metal shell and at least one diamond-metal composite layer disposed in the metal shell is prepared by the following method:

[0039] Making a hexahedral metal box: first punch out a hexahedral unfolded pattern from a metal sheet, leaving creases at the edges; fold along the edges to form a hexahedral box, and connect the edges with a metal adhesive; alternatively, laser cutting or wire cutting is used to form a hexahedral unfolded pattern, leaving creases at the edges; fold along the edges, and locally weld the edges to join adjacent edges; thus, a hexahedral copper foil box with an upper cover and an opening is obtained, and then placed into a mold;

[0040] Select a metal mesh: Use a metal mesh with a regular hexahedral structure or a regular octahedral honeycomb structure, with the mesh edge length L being 10-20 μm larger than the particle size D of a single diamond particle; place the prepared metal mesh inside the hexahedral metal box;

[0041] Arranging diamond particles: Arranging the diamond particles coated with the coating on each grid of the metal mesh using an arranging machine;

[0042] Gap filling: Place the hexahedral metal box with diamond particles and the mold on a mechanical vibration table with a vibration frequency of 2-10Hz, a vibration time of 5-20min, and an amplitude of 0.2-0.5mm. Spray copper powder onto the copper mesh in the vibration mode. Use electrostatic spraying technology to apply an electric field to directionally fill the metal powder into the mesh gaps. The electric field voltage is 5-10kV, and the particle size of the metal powder is 0.5-5μm. The metal powder fills the gaps in the metal mesh and reaches the same height as the metal mesh.

[0043] Multilayer stacking: After the gap filling step, a metal mesh is placed inside the hexahedral metal box, and the diamond particle arrangement and gap filling steps are repeated until the metal mesh is flush with the height of the hexahedral metal box. The upper cover at the opening is then placed, and the upper cover and the metal box are integrated to obtain a preform;

[0044] Sintering: The preform is placed in a vacuum sintering furnace for sintering to obtain a sintered composite material. In this step, when the metal shell, metal mesh, and metal powder are all made of copper, the furnace vacuum is <10Pa, the hot pressing pressure is 20-40MPa, the sintering temperature is 850-920°C, and the sintering time is 55-65 minutes. When the metal shell, metal mesh, and metal powder are all made of aluminum, the furnace vacuum is <10Pa, the hot pressing pressure is 20-40MPa, the sintering temperature is 520-620°C, and the sintering time is 30-50 minutes.

[0045] In the embodiment of the present application, a sandwich structure composite plate using diamond sheets as a reinforcement material layer is prepared by the following method:

[0046] The copper sheet and diamond sheet are stacked in the mold in the order of copper-diamond-copper, and then the mold is placed in a vacuum sintering furnace for sintering. The vacuum degree in the vacuum hot pressing furnace is 10 -1 ~10 -3 Pa, in a hydrogen-argon mixed reducing atmosphere with a hydrogen volume fraction of 5%, heat to 900~1100℃ at a rate of 5~20℃ / min, keep warm for 80~120min, and start pressurizing after the end of the insulation, the pressurization pressure is 20-40MPa, keep the pressure for 10-20min and then cool.

[0047] Example 1

[0048] like Figure 1-Figure 3As shown, the present embodiment provides a chip package heat dissipation liquid cooling device with a sandwich structure, including a heat dissipation base 10, a chip welding platform 20 located on the heat dissipation base 10 and a liquid cooling box 30 located at the bottom of the heat dissipation base 10, the bottom of the heat dissipation base 10 is provided with a microchannel structure 40; the liquid cooling box 30 is provided with a cavity 31 for accommodating the microchannel structure, the heat dissipation base is a sandwich structure composed of a surface copper layer 11, a diamond copper composite layer 12, and a bottom copper layer 13, and is a composite plate formed by sintering a hexahedral copper foil shell (thickness 250μm) and a diamond-copper composite layer placed in the copper foil shell; the diamond-copper composite layer includes a copper mesh (grid wall thickness 15μm) and a surface copper layer. The surface of the chip bonding station is coated with diamond particles with a 0.2μm thick metal Ti coating. The diamond particles are arranged in a grid of a copper mesh. The copper mesh has the same plane size as the inner bottom surface of the copper foil box. The gaps between the grid and the diamond particles are filled with copper powder. Cu atoms in the copper mesh diffuse through the coating to the diamond surface, forming a mixed transition zone. The chip bonding station is a sandwich structure composite plate with copper layers on the upper and lower surfaces, including a diamond sheet 21 (0.3mm thick) and a second copper layer 22 (1mm thick) covering the upper and lower surfaces of the diamond sheet 21. The chip bonding station 20 is welded to the heat sink base 10 via the second copper layer 22 on the bottom of the chip bonding station and the surface copper layer on the surface of the heat sink base.

[0049] In Example 1, the diamond metal composite plate used in the heat dissipation base is prepared by the following method:

[0050] (1) Punching out a hexahedron on a copper foil having a thickness of 250 μm, and leaving creases at the edges; gluing the edges of the copper foil in the shape of the unfolded diagram with metal adhesive to form a copper foil box body with an upper cover and an open upper surface; placing the copper foil box body with an open upper surface into a graphite mold;

[0051] (2) A copper mesh with a regular hexahedron grid is used to place diamond particles. The grid wall thickness is 15 μm, the edge length of the regular hexahedron is 15 μm larger than the particle size of the placed diamond particles, and the plane size of the copper mesh is the same as the bottom surface of the copper foil box. Then, the copper mesh is placed in the copper foil box;

[0052] (3) Using an arranging machine, artificial CVD diamond particles with a 0.5 μm Ti coating on the surface are arranged in each grid of the copper mesh, and the diamond particles have a particle size of 300 μm;

[0053] (4) The copper foil box body after arranging the diamonds is placed together with the graphite mold on a mechanical vibration table, and the vibration frequency of the vibration table is turned on to 10 Hz, the vibration time is 10 min, and the amplitude is controlled to 0.2 mm; the copper powder is a mixed copper powder mixed with nano-Al2O3, wherein the amount of nano-Al2O3 accounts for 0.5wt% of the weight of the copper powder, and the copper powder particle size is 3μm; an electrostatic spraying technology is used to apply an electric field so that the copper powder is directionally filled into the grid gaps on the copper mesh until the mixed copper powder fills the entire height of the copper mesh, and the electric field voltage is 5kV;

[0054] (5) Place the second layer of copper mesh and repeat the above steps (2) to (4);

[0055] (6) After the three layers are stacked, the copper mesh is flush with the height of the copper foil box, and the copper foil on the upper surface is covered and bonded to obtain a prefabricated part;

[0056] (7) The preform is subjected to vacuum hot pressing sintering, with the vacuum degree in the furnace being 1 Pa, the hot pressing pressure being 35 MPa, the sintering temperature being 900° C., and the sintering time being 60 min; and a composite material having a copper-diamond copper-copper sandwich structure formed as a sintered blank is obtained.

[0057] The sandwich structure composite board used in this embodiment is prepared by the following method:

[0058] Copper sheets (thickness 0.5 mm) and diamond sheets (thickness 250 μm) are stacked in the mold in the order of copper-diamond-copper, and then the mold is placed in a vacuum sintering furnace for sintering. The vacuum degree in the vacuum hot pressing furnace is 10 -1 Pa, in a hydrogen-argon mixed reducing atmosphere with a hydrogen gas volume fraction of 5%, the temperature was raised to 950℃ at a rate of 10℃ / min, and the temperature was kept at that temperature for 90min. After the temperature was kept at that temperature, the pressurization was started to be 30MPa, and the pressure was kept at that temperature for 15min before cooling.

[0059] Example 2

[0060] The present embodiment provides a chip packaging heat dissipation liquid cooling device with a sandwich structure, wherein the sandwich structure composite plate includes a ceramic material layer (alumina ceramic, 1 mm thick) located in the middle layer and a copper layer (0.8 mm thick) wrapped on the surface of the ceramic material layer; other features are the same as those in the above-mentioned embodiment 1.

[0061] Example 3

[0062] The present embodiment provides a chip packaging heat dissipation liquid cooling device with a sandwich structure, comprising a heat dissipation base, a chip welding platform located on the heat dissipation base, and a liquid cooling box located at the bottom of the heat dissipation base, wherein a microchannel structure is provided at the bottom of the heat dissipation base; a cavity for accommodating the microchannel structure is provided on the liquid cooling box, and the heat dissipation base is a diamond-copper composite plate, which includes a diamond sheet (with a thickness of 0.5 mm) located in the middle layer and a copper layer (with a thickness of 0.3 mm) coated on the surface of the diamond sheet, i.e., a copper-diamond-copper composite plate; the chip welding platform is a sandwich structure composite plate with copper layers on the upper and lower surfaces, and the sandwich structure composite plate adopts the same copper-diamond-copper composite plate as the heat dissipation base; the chip welding platform and the heat dissipation base are welded to each other by welding the copper layer at the bottom of the chip welding platform to the copper layer on the surface of the heat dissipation base.

[0063] Example 4

[0064] The present embodiment provides a chip packaging heat dissipation liquid cooling device with a sandwich structure. The chip welding station adopts a sandwich structure composite plate. The sandwich structure composite plate includes an aluminum oxide (Al2O3) ceramic layer (thickness 0.6mm) located in the middle layer and a copper layer (thickness 0.6mm) wrapped on the surface of the aluminum oxide (Al2O3) ceramic, forming a copper-aluminum oxide ceramic-copper structure; other features are the same as those of the above-mentioned embodiment 3.

[0065] According to the structures listed in Examples 1-4 of the chip welding platform described in this application, the intermediate layers in the sandwich structure composite plate can be replaced with ceramic materials such as diamond sheets, aluminum oxide (Al2O3) ceramics, zirconium oxide reinforced aluminum oxide (ZTA), aluminum nitride (AlN), and silicon nitride (Si3N4). When diamond sheets are used as the reinforcement material layer, their ultra-high in-plane thermal conductivity can quickly diffuse the heat generated by the chip laterally to the copper layer, avoiding local heat accumulation; the high hardness of diamond can absorb the thermal expansion mismatch stress between the copper layer and the chip, reducing the risk of interface delamination; it mainly exhibits the effects of ultra-high heat flux diffusion and high-frequency insulation. When aluminum oxide (Al2O3) ceramics are used as the reinforcement material layer, a stable insulating layer is formed between the copper layer and the chip, which can improve thermal conductivity while effectively reducing costs; it mainly exhibits the effect of low-cost heat dissipation. Zirconia-reinforced alumina (ZTA) as the reinforcement layer, due to its thermal expansion coefficient close to that of copper, can reduce copper layer warping caused by thermal cycling, enhance fracture toughness, and enhance interlayer peel strength; its primary function is to suppress thermal deformation. Aluminum nitride (AlN) as the reinforcement layer, with its thermal conductivity and thermal expansion coefficient perfectly matching those of silicon / silicon carbide chips, significantly reduces thermal stress and enables synergistic optimization of high frequency and high heat. Silicon nitride (Si3N4) as the reinforcement layer can adapt to oxidation of low-copper layers in extreme environments, primarily used for extreme environment load bearing and corrosion-resistant packaging.

[0066] On the basis of the above-mentioned embodiments 1-4, further, in some embodiments of the present application, the coating is a coating formed by one material selected from Ti, Cr, W, V, and Zr, or a composite coating formed by two or more materials; the thickness of the coating is 0.1 to 0.5 μm. In some embodiments, Ti is used as a target material, and a dense layer is formed on the surface of the diamond by magnetron sputtering, and a TiC phase is generated at the interface with a thickness of about 100 nm. In other embodiments, Ti and Cr targets are sputtered simultaneously to achieve an atomic-level mixed coating to improve the interface shear strength. In other embodiments, a composite layer of materials can be used. For example, a Cr layer (0.2-0.3 μm) is first formed on the surface of the diamond particles by magnetron sputtering, and then a W layer (0.1-0.2 μm) is formed on the surface of the Cr layer. In some embodiments, a Ti-Zr-Cu gradient coating can be used, with a bottom layer of 0.1-0.2μm Ti, which reacts with diamond at the interface to form TiC, enhancing bonding; a middle layer of 0.1-0.2μm Zr, which utilizes its high melting point to achieve a transition in thermal expansion coefficient; and a surface layer of 0.2-0.3μm Cu, which optimizes the wettability of the diamond surface. In addition to the aforementioned implementations, Ti / V can also be deposited alternately, with each layer 20-50nm thick, for a total coating thickness of 0.5μm.

[0067] Furthermore, based on the solutions of the above-mentioned embodiments 1-4, taking into account the requirements of chips with different powers, preferably, the thickness of the chip welding station is 0.5-10mm. For example, a thinner welding station can be used for low-power chips to reduce thermal resistance, while a thicker one can be used for high-power chips to increase structural stability. The thickness of the heat dissipation base is 8-10mm; wherein, the thickness of the copper layer on the upper and lower surfaces of the sandwich structure composite plate is 0.1-2mm, which optimizes welding wettability and reduces interface resistance; the thickness of the copper layer on the upper surface of the diamond copper composite plate is 0.1-2mm, which provides brazing compatibility and suppresses diamond-copper interface cracks; the thickness of the copper layer on the lower surface of the diamond copper composite plate is 2-3mm, which enhances the rigidity of the microchannel structure, resists fluid impact, and avoids uneven flow caused by flow channel collapse. The length and width of the chip welding station and the heat dissipation base are adjustable with the size of the embedded device to ensure good adaptability and heat dissipation effect. As Figure 3 As shown, based on the above embodiment, a further preferred solution is that the microchannel structure is a plurality of fins printed on the bottom of the heat sink base by 3D printing, which effectively improves the heat transfer and system heat dissipation capacity of the liquid cooling device without increasing the size of the cold plate. The 3D printing material is 10-50μm pure copper powder. Since the fins and the bottom copper layer of the heat sink base are made of the same material, there is no need for welding or bonding, and there will be no influence of the intermediate interface layer. The shape of the fins can be selected according to the requirements of the heat dissipation effect. For example, conventional straight fins can be selected, or wavy fins, needle-shaped / columnar fins, fractal tree-shaped fins, etc. can be used. Fin height affects the thermal boundary layer and heat exchange area. To balance thermal efficiency and pressure drop while accommodating microchannel fabrication, in some embodiments, the fin height is 2-5 mm. In the present embodiment, liquid cooling is employed. To avoid jet impingement failure, the relationship between the fin thickness δ and the spacing S between adjacent fins is S / δ = 1.5-2, and the fin thickness δ is 0.1-0.2 mm. Within this range, the fin thickness and spacing maximize heat exchange efficiency between the thermal boundary layer on the fin surface and the flow core. In this application, brazing is employed to achieve a solder connection between the chip bonding pad and the heat sink. The solder used for brazing can be selected from, but is not limited to, gold-tin solder, nano / micron silver paste, or nano / micron copper paste. Gold-tin solder has high thermal conductivity, a low melting point, and excellent mechanical strength. Its low wetting angle on copper surfaces allows for micron-level precision welding through localized heating. Furthermore, the gold-tin solder layer is highly compressible, effectively reducing interfacial delamination caused by thermal expansion mismatch and preventing deformation of 3D-printed fins at high temperatures. Although the unit price of gold-tin solder is 8-10 times that of tin, silver and copper, the improved reliability greatly reduces the maintenance rate. Therefore, in the preferred embodiment, gold-tin solder is mainly used to weld the chip welding platform and the heat dissipation base.

[0068] In the embodiment of the present application, in order to improve the heat exchange efficiency, the liquid cooling box is made of copper plate, aluminum plate, stainless steel plate, and heat sink. The liquid cooling box is provided with a fluid inlet end and a fluid outlet end.

[0069] Example 5

[0070] The present embodiment provides a chip packaging heat dissipation and liquid cooling device with a sandwich structure, comprising a heat dissipation base, a chip bonding station located on the heat dissipation base, and a liquid cooling box located at the bottom of the heat dissipation base, wherein a microchannel structure is provided at the bottom of the heat dissipation base; a cavity for accommodating the microchannel structure is provided on the liquid cooling box; the heat dissipation base is a sandwich structure consisting of a surface aluminum layer, a diamond-aluminum composite layer, and a bottom aluminum layer, and is a composite plate formed by sintering a hexahedral aluminum foil shell and a diamond-aluminum composite layer placed in the aluminum foil shell; the diamond-aluminum composite layer comprises an aluminum mesh and diamond particles coated with a coating on the surface, the diamond particles are arranged in a grid of a copper mesh, and the gaps between the grid and the diamond particles are filled with aluminum powder; Cu atoms in the aluminum mesh diffuse through the coating to the diamond surface, forming a mixed transition zone; the chip bonding station is a sandwich structure composite plate with copper layers on the upper and lower surfaces, comprising a diamond sheet and an aluminum layer covering the upper and lower surfaces of the diamond sheet; the chip bonding station and the heat dissipation base are welded to each other by the aluminum layer at the bottom of the chip bonding station and the aluminum layer on the surface of the heat dissipation base.

[0071] The sandwich structure composed of the surface aluminum layer, the diamond aluminum composite layer, and the bottom aluminum layer used in the heat dissipation base in the above-mentioned embodiment 5 is prepared by the following method.

[0072] (1) Punching out a hexahedron on a 300 μm thick aluminum foil, and leaving creases at the edges; gluing the edges of the copper foil in the shape of the expanded diagram with metal adhesive to form an aluminum foil box with an upper cover and an open upper surface; placing the aluminum foil box with an open upper surface into a graphite mold;

[0073] (2) Using an aluminum mesh with a regular hexahedron grid to place diamond particles, the grid wall thickness is 20 μm, the edge length of the regular hexahedron is 10 μm larger than the particle size of the placed diamond particles, and the plane size of the aluminum mesh is the same as the bottom surface of the aluminum foil box, and then the aluminum mesh is placed in the aluminum foil box;

[0074] (3) Using an arranging machine, artificial CVD diamond particles with a 0.5 μm Ti coating on the surface are arranged in each grid of the copper mesh, and the diamond particles have a particle size of 200 μm;

[0075] (4) The aluminum foil box with the diamonds arranged on it is placed together with the graphite mold on a mechanical vibration table. The vibration frequency of the vibration table is turned on and the vibration time is set to 10 Hz, the vibration time is set to 10 min, and the amplitude is controlled to 0.2 mm. An electrostatic spraying technique is used to apply an electric field so that aluminum powder (particle size is 3 μm) is directionally filled into the grid gaps on the aluminum mesh until the mixed aluminum powder fills the entire height of the aluminum mesh. The electric field voltage is 5 kV.

[0076] (5) Place the second layer of aluminum mesh and repeat the above steps (3) and (4);

[0077] (6) Stacking the aluminum mesh layers until the aluminum mesh is flush with the height of the aluminum foil box, and then covering and bonding the aluminum foil on the upper surface to obtain a prefabricated part;

[0078] (7) The preform is subjected to vacuum hot pressing sintering, with the vacuum degree in the furnace being 1 Pa, the hot pressing pressure being 60 MPa, the sintering temperature being 900°C, and the sintering time being 60 min; and a composite material having an aluminum-diamond aluminum-aluminum sandwich structure formed by a sintered blank is obtained.

[0079] The sandwich structure composite board used in Example 5 was prepared by the following method:

[0080] Aluminum sheets (thickness 1mm) and diamond sheets (thickness 250μm) are stacked in the mold in the order of aluminum sheet-diamond-aluminum sheet, and then the mold is placed in a vacuum sintering furnace for sintering. The vacuum degree in the vacuum hot pressing furnace is 10 -1 Pa, in a hydrogen-argon mixed reducing atmosphere with a hydrogen gas volume fraction of 5%, the temperature was raised to 600℃ at a rate of 10℃ / min, and the temperature was kept for 60min. After the temperature was kept, the pressurization was started to 35MPa, and the pressure was kept for 15min before cooling.

[0081] Preferably, based on the solution of the above-mentioned embodiment 5, the middle layer diamond sheet of the sandwich structure composite plate can be replaced by a ceramic material layer such as alumina (Al2O3) ceramic, zirconia reinforced alumina (ZTA), aluminum nitride (AlN), silicon nitride (Si3N4), etc.

[0082] Comparative Example 1

[0083] like Figure 4As shown, in this comparative example, a chip packaging heat dissipation liquid cooling device is provided, including a liquid cooling box (not shown in the figure), a heat dissipation base 10, a chip bonding platform 20 located on the heat dissipation base 10, a TIM layer 50 located on the bottom surface of the heat dissipation base 10, and a heat sink structure 60 located below the TIM layer, with a plurality of fins arranged below the heat sink structure; the liquid cooling box is located below the heat sink structure, and a cavity for accommodating the fins is provided on the liquid cooling box; the chip bonding platform is a ceramic-copper composite material, including a ceramic substrate, and copper layers located on the upper and lower surfaces of the ceramic substrate, and the heat dissipation base is a copper base; the heat dissipation base and the chip bonding platform are connected by welding.

[0084] Performance Testing

[0085] The performance tests and comparisons of the heat sinks described in the above-mentioned Examples 1-5 and Comparative Example 1 were conducted; wherein the thickness of the chip welding platform was set to 5mm, and the thickness of the copper layer on the upper and lower surfaces of the chip welding platform was 1mm. The thickness of the heat sink base in Examples 1-6 is 8mm, wherein the thickness of the copper layer on the upper surface is 1mm, the thickness of the copper layer on the lower surface is 2.5mm, the height of the fin is 3mm, the thickness is 0.1mm, and the fin spacing is 0.2mm. The thickness of the copper plate of the heat sink base in Comparative Example 1 is 6mm. The "chip junction temperature" is used to characterize the heat dissipation effect of the overall structure, and ANASY is used to compare and simulate the heat dissipation effects of different heat dissipation structures on high heat flux density GaN chips, and the heat flux density of the high-power GaN chip is set to 400W / cm 2 The test results are shown in Table 1.

[0086] Table 1: Performance test results

[0087]

[0088] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A chip packaging heat dissipation liquid cooling device with a sandwich structure, comprising a heat dissipation base and a chip welding platform located on the heat dissipation base, characterized in that: The chip bonding station is a sandwich-structured composite plate with copper layers on its upper and lower surfaces, and the heat dissipation base is a diamond-metal composite plate with a sandwich structure. The chip bonding station is welded to the heat dissipation base. The diamond-metal composite plate is a composite plate formed by sintering a hexahedral metal shell and at least one diamond-metal composite layer disposed within the metal shell. The diamond-metal composite layer comprises a metal mesh and diamond particles coated with a coating, wherein the coating is formed from one material selected from Ti, Cr, W, V, and Zr, or a composite coating formed from two or more materials. The coating has a thickness of 0.1 to 0.5 μm. The diamond particles are arranged in the mesh of the metal mesh, and the gaps between the mesh and the diamond particles are filled with metal powder. The metal shell, metal mesh, and metal powder are made of the same metal material, which is copper or aluminum. Metal atoms in the metal mesh diffuse through the coating to the diamond surface, forming a mixed transition zone.

2. The chip packaging heat dissipation liquid cooling device with a sandwich structure according to claim 1, characterized in that: The chip welding platform is a composite plate formed by sintering a reinforcement material layer located in the middle layer and a copper layer coated on the surface of the reinforcement material layer.

3. The chip packaging heat dissipation liquid cooling device with a sandwich structure according to claim 2, characterized in that: The reinforcement material layer is one of diamond sheets, alumina ceramics, zirconium oxide reinforced alumina ceramics, aluminum nitride ceramics, and silicon nitride ceramics.

4. The chip packaging heat dissipation liquid cooling device with a sandwich structure according to claim 3, characterized in that: The upper surface and the lower surface of the reinforcement material layer are respectively covered with copper layers, or the six sides of the reinforcement material layer are all covered with copper layers.

5. The chip packaging heat dissipation liquid cooling device with a sandwich structure according to claim 1, characterized in that: The thickness of the copper layer on the upper and lower surfaces of the sandwich structure composite plate is 0.1-2 mm; the thickness of the metal layer on the upper surface of the diamond metal composite plate is 0.1-2 mm, and the thickness of the metal layer on the lower surface is 0.2-3 mm.

6. The chip packaging heat dissipation liquid cooling device with a sandwich structure according to any one of claims 1 to 5, characterized in that: It also includes a liquid cooling box located at the bottom of the heat dissipation base, the bottom of the heat dissipation base is provided with a micro-channel structure; the liquid cooling box is provided with a cavity for accommodating the micro-channel structure.

7. The chip packaging heat dissipation liquid cooling device with a sandwich structure according to claim 6, characterized in that: The microchannel structure is a plurality of fins printed on the bottom of the heat dissipation base through 3D printing, and the 3D printing material is 10-50μm pure copper powder.

8. The chip packaging heat dissipation liquid cooling device with a sandwich structure according to claim 7, characterized in that: The height of the fin is 2-5 mm; the relationship S / δ between the fin thickness δ and the spacing S is 1.5-2, and the fin thickness δ is 0.1-0.2 mm.

9. The chip packaging heat dissipation liquid cooling device with a sandwich structure according to claim 1, characterized in that: The chip welding platform and the heat dissipation base are soldered by brazing, and the solder used for the brazing is one of gold-tin solder, nano silver paste, micron silver paste, nano copper paste and micron copper paste.

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