Heat spreading plate composite device, heat dissipation device and method of manufacturing the same

Abstract

The application discloses a heat diffusion plate composite device, a heat dissipation device and a preparation method thereof. The heat diffusion plate composite device comprises a heat-conducting metal layer, a metal-diamond composite material layer and a diamond substrate sheet which are connected together, and the heat-conducting metal layer, the metal-diamond composite material layer and the diamond substrate sheet are arranged in sequence from a cooling medium side to a chip heat source side in a thickness direction; the cooling medium side of the heat-conducting metal layer is provided with a heat exchange structure area and an outwardly protruding connecting structure; and the diamond substrate sheet faces the heat source and receives heat. The heat diffusion plate composite device has the following advantages: not only the conduction thermal resistance from the chip heat source side to the cooling medium is reduced, but also the size, the thermal expansion coefficient and the structural stiffness of the heat dissipation device, the chip and the packaging substrate are matched, and bending deformation, local depression or overall warping is avoided.

Description

Technical Field

[0001] This invention relates to the field of liquid cooling technology in microelectronic packaging, and particularly to a heat diffusion plate composite device, a heat dissipation device, and a method for preparing the same. Background Technology

[0002] As integrated circuits evolve towards 2.5D / 3D heterogeneous integration, high power density, and large-size packaging, the heat generated by high-performance computing chips, artificial intelligence chips, and power devices during operation continues to increase, significantly raising both local hot spots and overall heat flux density. Excessively high chip junction temperatures or uneven temperature distribution accelerate the aging of thermal interface materials, solder joint fatigue, interface delamination, and package warping, reducing device operating frequency and computing performance, thereby affecting device stability and lifespan. Therefore, minimizing the heat transfer path from the cooling medium to the chip's heat source and reducing the thermal resistance of the heat sink have become important development directions in the field of thermal management for high-power electronic devices.

[0003] Currently, commercial liquid-cooled heat sinks mainly consist of parallel channels and finned heat sinks fabricated on copper, aluminum, and alloy materials. To reduce the thermal resistance of the cooling medium to the chip heat source at the heat sink structural design level, directly reducing the thickness of the heat sink base plate (the thickness of the cooling medium to the heat sink surface in contact with the chip) is a natural choice. However, pure copper and pure aluminum have relatively limited Young's modulus and structural stiffness. Under loads such as heat sink assembly preload, seal clamping force, and cooling medium pressure, they are prone to bending deformation, local dents, or overall warping. This leads to uneven distribution of contact pressure between the heat sink and the chip heat source or package cover, increased local thickness of the thermal interface layer, or the formation of voids, deterioration of interface contact thermal resistance, and in severe cases, cracking of the solder layer. Invention patent application CN122206267A proposes a design where the inlet and outlet flow diversion channels and the staggered microchannels of the fins are connected on the same horizontal plane, combined with a multi-support area design, reducing the thickness of the heat sink and its base plate. However, due to limitations in the structural strength of the heat sink and the matching issues with the chip's heat source in terms of size, coefficient of thermal expansion, and structural stiffness, the thickness of the heat sink base plate is currently difficult to reduce to 1mm, regardless of whether it is a parallel channel design, a fin-designed microchannel liquid cooling plate, or a packaging cover plate.

[0004] Using materials with higher thermal conductivity, such as diamond, diamond-copper, and diamond-silver composites, to replace traditional copper materials in heat sink fabrication is a potential path to reduce the thermal resistance between the cooling medium and the chip's heat source, and has been a key focus of industry attention in recent years, as illustrated in CN121510960B. However, due to the ultra-high hardness of diamond, processing typical heat sink structures such as microchannels, micropores, and micropillars using these materials lags significantly behind traditional copper and aluminum-based heat sink processing technologies in terms of processing size and efficiency, and is also more difficult and costly. Furthermore, despite the outstanding thermal conductivity of diamond and its composites, when integrating the heat sink with the chip and packaging substrate at the packaging level—that is, when designing and manufacturing the heat sink and packaging cover as a single unit—matching issues arise regarding dimensions, coefficients of thermal expansion, and structural stiffness among the three components. Summary of the Invention

[0005] This invention provides a heat diffusion plate composite device, a heat dissipation device, and a method for preparing the same. It overcomes the mismatch problems in thermal expansion coefficient and mechanical structural strength faced by heat sinks based on diamond and other high thermal conductivity materials during processing, manufacturing, and packaging integration in the prior art. It reduces the thermal resistance generated between the cooling medium and the chip heat source to below the equivalent conduction thermal resistance of 1mm copper thickness, and has higher structural strength, bending stiffness, and matching ability with the chip-packaging substrate.

[0006] One of the technical solutions adopted by the present invention to solve its technical problem is: a heat diffusion plate composite device, comprising a thermally conductive metal layer, a metal-diamond composite material layer and a diamond substrate sheet that are compositely connected together, wherein the thermally conductive metal layer, the metal-diamond composite material layer and the diamond substrate sheet are arranged sequentially from the cooling medium side to the chip heat source side in the thickness direction; the cooling medium side of the thermally conductive metal layer is provided with a heat exchange structure area and an outwardly protruding connection structure; the diamond substrate sheet faces the chip heat source and receives heat.

[0007] The coefficients of thermal expansion of the thermally conductive metal layer, the metal-diamond composite material layer, and the diamond substrate decrease layer by layer, while the thermal conductivity and Young's modulus of the thermally conductive metal layer, the metal-diamond composite material layer, and the diamond substrate increase layer by layer.

[0008] A thin metal layer is provided between the metal-diamond composite material layer and the diamond substrate.

[0009] A welding layer is provided between the diamond substrate and the metal thin layer; the welding layer includes one of AuSn solder layer, SnAg solder layer, In-based solder layer or Ag sintered layer.

[0010] The chip heat source side of the metal thin layer is provided with a first NiAu layer; the first NiAu layer includes a nickel layer and a gold layer, the nickel layer serves as a diffusion barrier layer, and the gold layer serves as a solder wetting layer.

[0011] The diamond substrate has a first metallization layer on the cooling medium side; the first metallization layer is one of Ti / Pt / Au, Ti / Ni / Au, Cr / Au or Cr / Ni / Au.

[0012] The diamond substrate has a second metallization layer on the chip heat source side, which is a second NiAu layer. The second NiAu layer includes a nickel layer and a gold layer, wherein the nickel layer serves as a diffusion barrier layer and the gold layer serves as a solder wetting layer.

[0013] The connecting structure is columnar, with a height of 1mm to 10mm; the thermally conductive metal layer is a copper or aluminum material layer, with a thickness of 0.1mm to 3mm; the metal-diamond composite material layer is a copper-diamond composite material layer, an aluminum-diamond composite material layer, or a silver-diamond composite material layer, with a thickness of 0.1mm to 2mm; and the metal thin layer has a thickness of 0.01mm to 0.2mm.

[0014] The heat exchange structure region includes a first groove and a first boss located on the cooling medium side of the heat-conducting metal layer.

[0015] The first groove is a through groove that extends along the thickness direction, and the first protrusion is formed between adjacent first grooves; the cooling medium side of the metal-diamond composite material layer is provided with a second protrusion, the metal-diamond composite material layer is composited on the chip heat source side of the thermally conductive metal layer and the second protrusion is inserted into the first groove, and a second groove is formed between the second protrusion and the first protrusion.

[0016] The chip heat source side of the metal-diamond composite material layer is recessed with a third groove, and the cooling medium side of the diamond substrate is protruded with a third protrusion, which is adapted to be inserted into the third groove.

[0017] A thin metal layer is provided between the metal-diamond composite material layer and the diamond substrate, and the thin metal layer has a through hole adapted to the third boss, through which the third boss passes.

[0018] The second technical solution adopted by the present invention to solve its technical problem is: a heat diffusion plate composite device, comprising a thermally conductive metal layer and a metal-diamond composite material layer that are compositely connected together, wherein the thermally conductive metal layer and the metal-diamond composite material layer are arranged sequentially from the cooling medium side to the chip heat source side in the thickness direction; the cooling medium side of the thermally conductive metal layer is provided with a heat exchange structure area and an outwardly protruding connection structure; the metal-diamond composite material layer faces the chip heat source and receives heat.

[0019] The third technical solution adopted by the present invention to solve its technical problem is: a heat diffusion plate composite device, comprising a first layer, a second layer and a third layer connected together, wherein the first layer, the second layer and the third layer are arranged sequentially from the cooling medium side to the chip heat source side in the thickness direction; the coefficient of thermal expansion of the first layer, the second layer and the third layer decreases layer by layer, and the Young's modulus and thermal conductivity of the first layer, the second layer and the third layer increase layer by layer; the cooling medium side of the first layer is provided with a heat exchange structure area and an outwardly protruding connection structure; the third layer faces the heat source and receives heat.

[0020] The first layer has a thermal expansion coefficient of 15ppm / K to 25ppm / K, the second layer has a thermal expansion coefficient of 4ppm / K to 12ppm / K, and the third layer has a thermal expansion coefficient of 0.8ppm / K to 3ppm / K; the first layer has a Young's modulus of 60GPa to 130GPa, the second layer has a Young's modulus of 150GPa to 600GPa, and the third layer has a Young's modulus of 800GPa to 1200GPa; the first layer has a thermal conductivity of 150W / (m·K) to 400W / (m·K), the second layer has a thermal conductivity of 400W / (m·K) to 900W / (m·K), and the third layer has a thermal conductivity of 1000W / (m·K) to 2200W / (m·K).

[0021] The first layer is a thermally conductive metal layer or a first metal-diamond composite material layer, the second layer is a second metal-diamond composite material layer, and the third layer is a diamond substrate or a third metal-diamond composite material layer.

[0022] The fourth technical solution adopted by the present invention to solve its technical problem is: a heat dissipation device, including a heat sink, and also including the aforementioned heat diffusion plate composite device, wherein the heat sink is fixedly mounted on the cooling medium side of the thermally conductive metal layer and the heat sink cooperates with the heat exchange structure area of ​​the thermally conductive metal layer.

[0023] The connecting structure is columnar, and the surface of the heat sink facing the heat diffusion plate composite device is provided with a connecting groove; the connecting structure and the connecting groove are adapted to each other.

[0024] The heat sink is a jet heat sink, which includes an upper cover plate with a liquid storage chamber inside. The upper cover plate has an outlet and an inlet on the cooling medium side, and a jet hole and a return channel on the chip heat source side. The inner ends of the inlet and the jet hole are connected to the liquid storage chamber, and the return channel is connected to the outlet. The outer end of the jet hole faces the heat exchange structure area. The cooling medium enters the liquid storage chamber through the inlet, is jetted towards the heat exchange structure area through the jet hole for heat exchange, and then flows out through the return channel and the outlet.

[0025] The radiator is a toothed radiator, which includes multiple staggered cooling teeth, with flow channels formed between adjacent cooling teeth for the cooling medium to circulate.

[0026] The fifth technical solution adopted by the present invention to solve its technical problem is: the preparation method of the heat dissipation device, comprising:

[0027] A thermally conductive metal layer and a heat sink are fabricated, wherein the thermally conductive metal layer has a connection structure and a heat exchange structure region;

[0028] The thermally conductive metal layer and the heat sink are connected together;

[0029] A metal-diamond composite material layer is compositely connected to the heat source side of the thermally conductive metal layer;

[0030] A thin metal layer is compositely bonded to the chip heat source side of the metal-diamond composite layer, and a first NiAu layer is prepared on the chip heat source side of the thin metal layer;

[0031] The surface of the diamond substrate is metallized on the cooling medium side, and the diamond substrate is connected to the first NiAu layer of the metal thin layer through a welding layer.

[0032] Compared with the prior art, this technical solution has the following advantages:

[0033] The heat dissipation plate composite device includes a thermally conductive metal layer, a metal-diamond composite material layer, or a thermally conductive metal layer, a metal-diamond composite material layer, and a diamond substrate arranged sequentially from the cooling medium side to the chip heat source side in the thickness direction. This not only reduces the thermal resistance from the chip heat source side (e.g., the chip) to the cooling medium, lowering it to an equivalent thermal resistance of copper of thickness 1 mm or less, but also ensures that the dimensions, coefficients of thermal expansion, and structural stiffness of the heat sink, chip, and packaging substrate are matched, preventing bending deformation, local dents, or overall warping. The heat dissipation plate composite device includes a first layer, a second layer, and a third layer arranged sequentially from the cooling medium side to the chip heat source side in the thickness direction. The coefficients of thermal expansion of the first, second, and third layers decrease progressively, while the Young's modulus and thermal conductivity increase progressively. This not only reduces the thermal resistance from the chip heat source side (e.g., the chip) to the cooling medium, but also ensures that the dimensions, coefficients of thermal expansion, and structural stiffness of the heat sink, chip, and packaging substrate are matched, preventing bending deformation, local dents, or overall warping. The connecting structure is used to mechanically fix, connect and isolate the heat sink, and improve the overall rigidity and strength of the heat diffusion plate composite device through the support of the connecting structure. Thus, without significantly increasing the thickness of the heat-conducting metal layer, the heat diffusion plate composite device can withstand the heat sink assembly preload, the sealing clamping force, the cooling medium pressure and the jet fluid impact load, reducing the risk of bending deformation, local dents or overall warping of the heat-conducting metal layer and the composite layer below it. Attached Figure Description

[0034] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0035] Figure 1 This is a cross-sectional structural diagram of the heat dissipation device in Embodiment 1 of the specific implementation method;

[0036] Figure 2 This is a cross-sectional structural diagram of the heat dissipation device in Embodiment 2 of the specific implementation method. Detailed Implementation

[0037] The technical solution of this application will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of this application, and not all embodiments. It should be noted that the following embodiments are only used to illustrate the technical solution of this invention and should not be construed as limiting the scope of protection of this invention; other embodiments obtained by those skilled in the art without creative effort are all within the scope of protection of this application.

[0038] like Figure 1 As shown, this embodiment provides a heat dissipation device for liquid cooling in microelectronic packaging, a heat diffusion plate composite device, and a liquid-cooled radiator. The heat dissipation device includes a heat diffusion plate composite device and a liquid-cooled radiator (jet radiator). Figure 1The upper part is a liquid-cooled heat sink, and the lower part is a heat diffusion plate composite device. The heat sink device is oriented from top to bottom in the thickness direction from the cooling medium side to the chip heat source side. The thermal conductivity, coefficient of thermal expansion, and Young's modulus of the heat diffusion plate composite device all change in a gradient.

[0039] The liquid-cooled heat sink includes an upper cover plate 000, which has a liquid storage chamber 004 inside. The cooling medium side (upper surface in the figure) of the upper cover plate 000 is recessed with an outlet 001 and an inlet 003, and the inner end of the inlet 003 is connected to the liquid storage chamber 004. The chip heat source side (lower surface in the figure) of the upper cover plate 000 is recessed with a connecting groove, multiple spray holes 002 and multiple return channels 005, the inner end of the spray holes 002 is connected to the liquid storage chamber 004, and the return channels 005 are connected to the outlet 001.

[0040] The heat diffusion plate composite device is located below the liquid-cooled heat sink and between the cooling medium and the chip heat source. It reduces the thermal resistance between the heat source and the cooling medium, and improves the matching of dimensions, coefficient of thermal expansion, and structural rigidity among the heat sink, chip, and packaging substrate. The heat diffusion plate composite device includes a connection structure 101, a thermally conductive metal layer, a metal-diamond composite material layer 301, and a diamond substrate 701, arranged sequentially from the cooling medium side to the chip heat source side (from top to bottom in the figure). A thin metal layer 401 is also provided between the metal-diamond composite material layer 301 and the diamond substrate 701. The aforementioned thermally conductive metal layer is the first layer, the metal-diamond composite material layer 301 is the second layer, and the diamond substrate 701 is the third layer.

[0041] The thermally conductive metal layer includes a lower cover plate 200, which forms part or entirely of the thermally conductive metal layer. The connecting structure 101 protrudes from the cooling medium side of the lower cover plate 200 (the side facing the upper cover plate 000 in the figure). To improve the structural strength and bending strength of the heat diffusion composite device, the multiple connecting structures 101 can be arranged in an array on the cooling medium side (the upper surface in the figure). The cooling medium side of the lower cover plate 200 also has a heat exchange structure area. The metal-diamond composite material layer 301 is disposed on the chip heat source side of the lower cover plate 200 (the side away from the upper cover plate 000 in the figure). The metal thin layer 401 is disposed below the metal-diamond composite material layer 301 (on the chip heat source side). The diamond substrate 701 is connected to the metal thin layer 401 below (on the chip heat source side) through a welding layer. Specifically, the thermally conductive metal layer primarily provides the processing foundation and metal connection foundation for the heat exchange structure area on the cooling medium side, while the metal-diamond composite material layer 301 and the diamond substrate 701 provide support for a higher Young's modulus. Thus, the heat diffusion plate composite device forms a composite structure in the thickness direction from the cooling medium side to the chip heat source side: the coefficient of thermal expansion decreases progressively (thermally conductive metal layer > metal-diamond composite material layer 301 > diamond substrate 701), the Young's modulus increases progressively (thermally conductive metal layer < metal-diamond composite material layer 301 < diamond substrate 701), and the thermal conductivity increases progressively (thermally conductive metal layer < metal-diamond composite material layer 301 < diamond substrate 701).

[0042] The upper cover plate 000 and the lower cover plate 200 are arranged opposite to each other, forming a liquid-cooled heat exchange space for the flow of cooling medium between them. The cooling medium enters the liquid storage chamber 004 through the inlet 003 and is then sprayed towards the heat exchange structure area of ​​the lower cover plate 200 through multiple spray holes 002. The cooled medium, after heat exchange, is collected in the return channel 005 and discharged from the outlet 001.

[0043] The connecting structure 101 is located on the cooling medium side of the lower cover plate 200 and protrudes towards the upper cover plate 000. If the connecting structure 101 is a columnar structure, its height is 1mm to 10mm. Depending on the requirements, the connecting structure 101 and the lower cover plate 200 may be integrally formed, or the connecting structure 101 may be a separate metal structure fixed to the lower cover plate 200. The connecting structure 101 and the connecting groove of the upper cover plate 000 are compatible. The connecting structure 101 is used for mechanical fixing, connection, and stress isolation of the radiator, and improves the overall rigidity and strength of the heat diffusion plate composite device through its supporting effect. Therefore, without significantly increasing the thickness of the thermally conductive metal layer, the heat diffusion plate composite device can withstand the radiator assembly preload, sealing clamping force, cooling medium pressure, and jet fluid impact load, reducing the risk of bending deformation, local dents, or overall warping of the lower cover plate 200 and its underlying composite layer. Specific structure: Multiple connecting structures 101 can be located in the edge region, middle region, or between the jet heat exchange structure region of the lower cover plate 200, as shown in the figure, divided into three groups. Two groups are located in the edge region, one group is located in the middle region, and the heat exchange structure region is located between two adjacent groups. Each group may include multiple spaced connecting structures 101, which are spaced so that the upper cover plate 000 and the lower cover plate 200 form a multi-point or multi-region connection structure after assembly. This structure can reduce the deflection effect of the liquid cooling cavity pressure on the lower cover plate 200, so that the thermally conductive metal layer does not need to be increased in thickness (such as a pure copper layer) to obtain mechanical strength, thereby avoiding the problem of longer heat conduction path from heat source to cooling medium and increased solid thermal resistance due to excessive thickness (pure copper thickness).

[0044] Furthermore, the heat exchange structure region on the cooling medium side of the thermally conductive metal layer is provided with an array structure of multiple first protrusions 201 and multiple first grooves 202, with the first grooves 202 formed between adjacent first protrusions 201. The cooling medium ejected from the injection holes 002 can directly impact the top of the first protrusion 201, the bottom of the first groove 202, or the heat exchange surface formed by the first protrusion 201 and the first groove 202. By providing the first protrusions 201 and the first grooves 202, the contact area between the cooling medium and the thermally conductive metal layer can be increased, the flow boundary layer and the thermal boundary layer can be broken, and the local heat exchange capacity can be improved. At the same time, the first protrusions 201 and the first grooves 202 can also improve the fluid circulation path, improve fluid circulation, reduce local stagnant areas, and help improve the residual stress of the structure. Specifically, the structural feature dimensions of the first protrusions 201 and the first grooves 202 can be 0.01mm to 2mm, and the cross-section can be square. The first boss 201 and the first groove 202 can be manufactured by die casting, stamping, milling, laser etching, chemical etching, electrochemical corrosion, chemical polishing, or a combination of one or more of the above processes. Preferably, the first boss 201 and the first groove 202 are integrally formed with the lower cover plate 200 to reduce interfacial thermal resistance and improve structural strength.

[0045] The thermally conductive metal layer can be a copper or aluminum material layer, with a thickness ranging from 0.1 mm to 3 mm. In this embodiment, the copper material layer is preferably made of oxygen-free copper or a copper alloy to balance thermal conductivity, machinability, weldability, and reliable sealing connection with the upper cover plate 000. The thermally conductive metal layer is positioned close to the cooling medium to quickly transfer heat from the lower composite layer to the heat exchange structure area.

[0046] The metal-diamond composite material layer 301 is disposed below the thermally conductive metal layer. The metal-diamond composite material layer 301 can be a copper-diamond composite material layer, an aluminum-diamond composite material layer, or a silver-diamond composite material layer, with a thickness ranging from 0.1 mm to 2 mm. The metal-diamond composite material layer 301 has a high thermal conductivity, a low coefficient of thermal expansion, and a high Young's modulus, which can reduce the thermal resistance in the thickness direction of the heat diffuser while improving the overall stiffness of the composite structure and suppressing warping deformation during thermal cycling.

[0047] The thin metal layer 401 is disposed below the metal-diamond composite material layer 301. The thin metal layer 401 can be a copper thin layer, an aluminum thin layer, a silver thin layer, or other solderable metal thin layer, with a thickness ranging from 0.01 mm to 0.2 mm and a flatness ≤ 50 μm. The thin metal layer 401 serves as a metal connection transition layer between the metal-diamond composite material layer 301 and the underlying welding layer. On one hand, the thin metal layer 401 can improve the solderability and metallization connection performance of the lower surface of the metal-diamond composite material layer 301; on the other hand, the thin metal layer 401 has a small thickness, thus avoiding a large pure metal thermal resistance. Furthermore, the chip heat source side of the thin metal layer 401 is provided with a nickel-gold plating layer or a first NiAu layer 501. The first NiAu layer 501 includes a nickel layer and a gold layer; the nickel layer acts as a diffusion barrier layer to suppress excessive diffusion between the thin metal layer 401 and the solder; the gold layer acts as a welding wetting layer to improve wettability and interface reliability during subsequent welding processes. The thickness of the nickel layer can be 0.1 μm to 1 μm, and the thickness of the gold layer can be 0.1 μm to 0.5 μm.

[0048] The diamond substrate 701 is disposed on the chip heat source side of the metal thin layer 401 (below the metal thin layer 401 in the figure) and close to the heat source. The diamond substrate 701 has a high thermal conductivity, a low coefficient of thermal expansion, and a high Young's modulus, enabling it to quickly receive heat generated by the heat source and diffuse heat in the planar direction. A first metallization layer is disposed on the cooling medium side (upper surface) of the diamond substrate 701. The first metallization layer can be one of Ti / Pt / Au, Ti / Ni / Au, Cr / Au, or Cr / Ni / Au. Preferably, the surface metallization planarity of the diamond substrate 701 is ≤50μm. It should be noted that, for clarity of the structure in the accompanying drawings, Figure 1 and Figure 2 The first metallization layer is not shown or labeled separately. The first metallization layer is actually formed on the cooling medium side surface of the diamond substrate 701 and is located between the AuSn solder layer 601 and the diamond substrate 701.

[0049] In some embodiments, the thermally conductive metal layer, the metal-diamond composite material layer 301, and the metal thin layer 401 can be formed by a bonding welding process. Specifically, a metal substrate having a connecting structure 101 and a thermally conductive metal layer is prepared in advance, and the metal-diamond composite material layer 301 and the metal thin layer 401 are prepared; then, the thermally conductive metal layer, the metal-diamond composite material layer 301, and the metal thin layer 401 are connected to form a composite structure by means of laser welding, brazing, diffusion welding, thermocompression welding, transient liquid phase bonding, sintering bonding, vacuum welding, or electron beam welding; then, the surface-metallized diamond substrate 701 and the metal thin layer 401 are welded together, for example, by connecting the surface-metallized diamond substrate 701 and the metal thin layer 401 through a welding layer 601.

[0050] In other embodiments, the thermally conductive metal layer, the metal-diamond composite material layer 301, and the metal thin layer 401 can also be formed through a direct forming process. For example, a composite plate containing the thermally conductive metal layer, the metal-diamond composite material layer 301, and the metal thin layer 401 can be prepared using die casting, electroplating, composite rolling, or other forming processes. Further, for example, the connecting structure, thermally conductive metal layer, metal-diamond composite material, and metal thin layer prepared by die casting, electroplating, etc., can have an array structure of grooves, bumps, etc., and a metal thin layer formed on the upper surface of the thermally conductive metal layer through one or more processes such as mechanical thinning, milling, chemical etching, electrochemical corrosion, chemical polishing, and electroplating. The thinning process includes one or more of mechanical grinding, polishing, turning, milling, and grinding.

[0051] In this embodiment, a solder layer is provided between the diamond substrate 701 and the metal thin layer 401. Specifically, the solder layer can be an AuSn solder layer 601, or a SnAg solder layer, an In-based solder layer, or an Ag sintered layer. The thickness of the solder layer can be 50μm to 300μm. Preferably, an AuSn solder layer 601 is used as the solder layer. The thermal conductivity of the AuSn solder layer is 50W / (m·K) to 65W / (m·K), the coefficient of thermal expansion is 14ppm / K to 17ppm / K, and the melting point is 270℃ to 290℃, making it suitable for heat sink connections of high-power chips or power devices. The solder layer 601 can be provided by pre-formed solder pads, vapor-deposited solder, screen-printed solder, or electroplated solder, and the connection is completed by vacuum reflow soldering, thermoforming soldering, or atmosphere-protected soldering.

[0052] On the side of the diamond substrate 701 away from the AuSn solder layer 601, a second NiAu layer 801 may also be provided. The second NiAu layer 801 is used to metallize the chip heat source side of the diamond substrate 701, so that it can form a reliable connection with the chip, package cover, power device, sintering layer or thermally conductive interface material, and reduce the interface contact thermal resistance.

[0053] In this embodiment, the connecting structure 101, the thermally conductive metal layer, the metal-diamond composite material layer 301, and the diamond substrate 701 together form a heat diffusion plate composite device whose coefficient of thermal expansion, Young's modulus, and thermal conductivity change synergistically along the thickness direction. Specifically, the coefficient of thermal expansion of the thermally conductive metal layer is greater than that of the metal-diamond composite material layer 301, and the coefficient of thermal expansion of the metal-diamond composite material layer 301 is greater than that of the diamond substrate 701, thereby forming a gradient structure of the coefficient of thermal expansion that gradually decreases from the cooling medium side to the chip heat source side. At the same time, the Young's modulus and thermal conductivity of the metal-diamond composite material layer 301 and the diamond substrate 701 are higher than those of the thermally conductive metal layer, so that the heat diffusion plate composite device forms a composite reinforcement structure in which high-rigidity materials are introduced step by step from the cooling medium side to the chip heat source side.

[0054] Preferably, when the thermally conductive metal layer is a copper layer, its coefficient of thermal expansion is 15ppm / K to 18ppm / K; when the metal-diamond composite layer 301 is a copper-diamond composite layer, its coefficient of thermal expansion is 4ppm / K to 10ppm / K; and the coefficient of thermal expansion of the diamond substrate 701 is 0.8ppm / K to 1.5ppm / K. Alternatively, the thermally conductive metal layer is aluminum, with a coefficient of thermal expansion of 20ppm / K to 25ppm / K; when the metal-diamond composite layer is an aluminum-diamond composite layer, its coefficient of thermal expansion is 5ppm / K to 12ppm / K; and the coefficient of thermal expansion of the diamond substrate is 0.8ppm / K to 1.5ppm / K. Through this gradient transition, the thermal expansion mismatch between the heat sink, chip, and packaging substrate can be reduced, lowering the risk of interfacial shear stress, warpage, and delamination during power cycling and temperature cycling.

[0055] Furthermore, the Young's modulus of the thermally conductive metal layer can be 60 GPa to 130 GPa, the Young's modulus of the metal-diamond composite layer can be 150 GPa to 600 GPa, and the Young's modulus of the diamond substrate 701 can be 800 GPa to 1200 GPa. Through the above-mentioned differences in Young's modulus, the metal-diamond composite layer 301 and the diamond substrate 701 can improve the overall bending stiffness without significantly increasing the thickness of the pure metal base plate, thereby reducing bending deformation under assembly load, cooling medium pressure, and thermal load.

[0056] Furthermore, the thermal conductivity of the thermally conductive metal layer can be 150 W / (m·K) to 400 W / (m·K), the thermal conductivity of the metal-diamond composite material layer 301 can be 400 W / (m·K) to 900 W / (m·K), and the thermal conductivity of the diamond substrate 701 can be 1000 W / (m·K) to 2200 W / (m·K). The diamond substrate 701 is positioned close to the heat source side of the chip, and the metal-diamond composite material layer 301 is located between the diamond substrate 701 and the thermally conductive metal layer. This simultaneously achieves rapid hotspot diffusion, low thermal resistance in the thickness direction, and enhanced structural rigidity, making the equivalent thermal resistance of the heat diffusion plate composite device less than or equal to the thermal resistance of 1 mm copper conduction.

[0057] In traditional liquid-cooled radiators made of copper, aluminum, or alloy materials, if the radiator base plate is designed to be thick, the heat generated by the heat source needs to travel a long metal heat conduction path to reach the cooling medium, resulting in increased thermal resistance in the thickness direction. If the radiator base plate is designed to be thin, its overall rigidity and bending resistance are insufficient, and it is prone to deformation under the action of assembly preload, sealing clamping force, and cooling medium pressure, resulting in uneven interface contact pressure, local thickening of the heat conduction interface layer, cracking of the weld layer, or sealing failure.

[0058] In this embodiment, the connecting structure 101 is used to mechanically fix and stress-isolate the upper heat sink, and to improve the overall rigidity of the heat diffusion plate composite device through its support function; the metal-diamond composite material layer 301 and the diamond substrate 701 are used to provide support with high thermal conductivity, low thermal expansion and high Young's modulus; the metal thin layer 401, the first NiAu layer 501 and the AuSn solder layer 601 are used to provide a reliable metal connection interface. Therefore, this embodiment does not need to rely on a thick pure copper base plate to obtain structural strength, nor does it need to use an excessively thin pure copper base plate to reduce thermal resistance, thus effectively solving the problems of poor heat dissipation due to excessively thick pure copper between the cooling medium and the heat source, and insufficient mechanical structure due to excessively thin pure copper.

[0059] During operation, the cooling medium enters the storage chamber 004 through the inlet 003 and is sprayed through the spray holes 002 onto the first protrusion 201 and the first groove 202 area on the thermally conductive metal layer. Forced convection heat transfer is formed between the top of the first protrusion 201, the bottom of the first groove 202, and adjacent first protrusions 201, absorbing the heat transferred from the heat source. Subsequently, the cooled medium flows along the return channel 005 and is discharged through the outlet 001. Simultaneously, the heat generated by the heat source is sequentially transferred to the cooling medium through the second NiAu layer 801, the diamond substrate 701, the first metallization layer, the AuSn solder layer 601, the first NiAu layer 501, the thin metal layer 401, the metal-diamond composite material layer 301, and the thermally conductive metal layer.

[0060] Because the diamond substrate 701 is positioned close to the heat source, local hot spots on the heat source side of the chip can quickly diffuse within the diamond substrate 701. Since the metal-diamond composite material layer 301 is located between the thermally conductive metal layer and the diamond substrate 701, heat can continue to be transferred to the cooling side with lower thermal resistance, while simultaneously suppressing excessive warping of the composite structure under thermal load. Because the connecting structure 101 mechanically fixes and connects the upper cover plate 000 and the liquid cooling cavity, the cooling medium pressure and assembly pressure are less likely to directly cause deformation of the thermally conductive metal layer and the composite layer. Therefore, this embodiment can improve the heat dissipation performance, structural stability, and long-term service reliability of the liquid cooler.

[0061] The above description uses the example of "the first layer being a thermally conductive metal layer, the second layer being a metal-diamond composite material layer, and the third layer being a diamond substrate," but it is not limited to this. Depending on the needs: the first layer can also be a first metal-diamond composite material layer (the second layer a second metal-diamond composite material layer), and the third layer can also be a third metal-diamond composite material layer. If the first layer is a first metal-diamond composite material layer, metal powder and diamond micron powder are mixed in a predetermined ratio and integrally formed in a mold using electroplating, casting, hot pressing sintering, liquid phase infiltration, or powder metallurgy processes. After demolding, a first metal-diamond composite material layer with a first boss 201, a first groove 202, and a connecting structure 101 is directly obtained. By adjusting the "metal material type," "diamond particle size," and / or the "ratio of metal powder to diamond micron powder," the thermal expansion coefficient of the first layer is greater than that of the second layer, which is greater than that of the third layer. The Young's modulus and thermal conductivity of the first layer are less than those of the second layer, which are less than those of the third layer.

[0062] Example 1

[0063] like Figure 1As shown, the heat diffusion plate composite device includes, from top to bottom, a connecting structure 101, a thermally conductive metal layer, a metal-diamond composite material layer 301, a metal thin layer 401, and a diamond substrate 701. This heat diffusion plate composite device is assembled and connected to a jet heat sink, which includes an upper cover plate 000, which has an outlet 001, a jet hole 002, an inlet 003, a liquid storage chamber 004, and a return channel 005. The lower cover plate 200 serves as the thermally conductive metal layer. On the cooling medium side of the lower cover plate 200, there is a connecting structure 101, a first boss 201, and a first groove 202. On the chip heat source side of the lower cover plate 200, there are, in sequence, a metal-diamond composite material layer 301, a metal thin layer 401, a first NiAu layer 501, an AuSn solder layer 601, a first metallization layer, a diamond substrate 701, and a second NiAu layer 801. Since the first boss 201, the first groove 202, the jet heat exchange structure area and the connecting structure 101 are mainly formed on the thermally conductive metal layer, it avoids directly processing the complex micro-channel structure (first boss 201 and first groove 202) in the diamond substrate 701 or the metal-diamond composite material layer 301, thereby reducing the processing difficulty and manufacturing cost.

[0064] In this embodiment, the heat dissipation device is assembled or welded to the heat dissipation plate composite device and the jet radiator, and used in conjunction. However, this is not a limitation. In other embodiments, the heat dissipation plate composite device can also be assembled or welded to the interlaced tooth radiator, parallel channel radiator, or other liquid cooling heat dissipation structures via the connecting structure 101. The interlaced tooth radiator includes multiple staggered heat dissipation teeth, and a flow channel for the cooling medium to circulate is formed between adjacent heat dissipation teeth. The cooling medium exchanges heat with the thermally conductive metal layer through the flow channel.

[0065] In this embodiment, the lower cover plate 200 is made of oxygen-free copper with a thickness of 1.5 mm; the upper cover plate 000 is made of a metal material with a thermal expansion coefficient matching that of the lower cover plate 200, with a thickness of 5 mm. The connecting structure 101 is made of oxygen-free copper and is a frustum-shaped connecting structure with a height of 3.3 mm, an upper diameter of 2.5 mm, a lower diameter of 2.78 mm, and a sidewall slope of 3°. The liquid storage chamber 004 is a hollow layer of 70 mm × 48 mm × 1 mm. The spray hole 002 is a hollow structure with an upper conical shape and a lower cylindrical shape, wherein the upper diameter of the upper conical section is 0.6 mm, the lower diameter is 0.3 mm, and the height is 1 mm, and the lower cylindrical section has a diameter of 0.3 mm and a height of 1 mm. The return channel 005 is a strip channel of 45 mm × 1 mm × 0.5 mm. As needed, the end of the return channel collects water and is provided with an outlet channel connecting to the water outlet.

[0066] The metal-diamond composite layer 301 is made of copper-diamond composite material and has a thickness of 1 mm; the metal thin layer 401 is made of copper and has a thickness of 0.1 mm; the first NiAu layer 501 and the second NiAu layer 801 both include a nickel layer and a gold layer, wherein the nickel layer has a thickness of 0.5 μm and the gold layer has a thickness of 0.2 μm; the AuSn solder layer 601 has a thickness of 100 μm; and the diamond substrate 701 has a thickness of 0.3 mm. The diamond substrate 701 is positioned facing the chip heat source side and is used to form a thermally conductive connection with the chip, package cover, or power device.

[0067] The method for preparing the heat dissipation device includes:

[0068] Fabricate the lower cover plate 200 and the heat sink;

[0069] A connecting structure 101, a first boss 201, a first groove 202, and a connecting slot are fabricated on the lower cover plate 200. Specifically, the connecting structure 101, the first boss 201, the first groove 202, and the connecting slot are formed on the first surface of the lower cover plate 200 through processes such as milling, micro-milling, laser processing, electrochemical processing, micro-electroforming, stamping, or die casting. Multiple connecting structures 101 are spaced apart along the upper surface of the lower cover plate 200 and protrude towards the upper cover plate 000, serving to mechanically fix, connect, and stress-isolate the structures containing the upper cover plate 000, the liquid storage chamber 004, and the injection hole 002 after the upper cover plate 000 and the lower cover plate 200 are assembled. Multiple first bosses 201 are disposed between adjacent connecting structures 101, and a first groove 202 is formed between adjacent first bosses 201. The first bosses 201 and the first grooves 202 together constitute the heat exchange structure area for injection.

[0070] Through processes such as drilling, milling, laser drilling, micro-electroforming, etching, or precision stamping, an outlet 001, a jet hole 002, an inlet 003, a liquid storage chamber 004, and a return channel 005 are machined on the upper cover plate 000. The inlet 003 communicates with the liquid storage chamber 004. The jet hole 002 is located below the liquid storage chamber 004 and faces the area of ​​the first boss 201 and the first groove 202 on the lower cover plate 200. The return channel 005 communicates with the outlet 001 and is used to discharge the cooling medium after heat exchange.

[0071] The upper cover plate 000 and the lower cover plate 200 are assembled. Specifically, the upper cover plate 000 and the lower cover plate 200 are matched and aligned using positioning holes, positioning pins, cross alignment marks, or precision bonding fixtures, so that the injection hole 002 corresponds to the heat exchange structure area on the lower cover plate 200, including the first boss 201 and the first groove 202, and the connecting structure 101 is correspondingly abutted against or connected to the predetermined connecting area of ​​the upper cover plate 000, such as the connecting groove mentioned above. Further, a sealed connection between the upper cover plate 000 and the lower cover plate 200 is achieved through connection processes such as brazing, vacuum welding, diffusion welding, laser welding, electron beam welding, sintering connection, mechanical pressing, thermoforming, solid-phase diffusion, or bolt assembly.

[0072] A copper-diamond composite material layer is attached to the second surface of the lower cover plate 200. Specifically, the second surface of the lower cover plate 200 and the surface of the copper-diamond composite material layer are first subjected to deoxidation, degreasing, roughening, activation and drying treatments; then, the copper-diamond composite material layer is attached to the second surface of the lower cover plate 200 by vacuum brazing, hot press welding, diffusion welding, transient liquid phase bonding or Ag sintering bonding processes.

[0073] A thin metal layer 401 is formed on the side of the copper-diamond composite material layer away from the lower cover plate 200. Specifically, the thin metal layer 401 can be formed by electroplating, chemical plating, magnetron sputtering, vapor deposition, thermal spraying, cold spraying, or rolling composite methods. Preferably, the copper thin layer is formed by electroplating copper or sputtering thickened copper process, so that the surface of the thin metal layer 401 is flat and has good solderability. After the thin metal layer 401 is formed, the surface of the thin metal layer 401 is ground or polished to make its flatness less than or equal to 50 μm, so as to improve the bonding quality of the subsequent welding interface.

[0074] A first NiAu layer 501 is prepared on the surface of the metal thin layer 401. Specifically, a nickel layer and a gold layer are sequentially formed on the surface of the metal thin layer 401 by chemical plating, electroplating, sputtering, or vapor deposition. The nickel layer acts as a diffusion barrier layer to suppress excessive element diffusion between the metal thin layer 401 and the AuSn solder layer 601; the gold layer acts as a solder wetting layer to improve the wettability and interfacial bonding strength of the AuSn solder layer 601 during the soldering process.

[0075] The diamond substrate 701 undergoes double-sided metallization: a first metallization layer is formed on the side of the diamond substrate 701 facing the metal-diamond composite layer 301, and a second NiAu layer 801 is formed on the side of the diamond substrate 701 facing the heat source. Specifically, the first metallization layer can be formed into a Ti / Pt / Au, Ti / Ni / Au, Cr / Au, or Cr / Ni / Au structure through magnetron sputtering, evaporation, or other thin film deposition processes; the second NiAu layer 801 can be formed into a nickel layer and a gold layer sequentially through chemical plating, electroplating, sputtering, or evaporation processes. The second NiAu layer 801 is used to improve the connection reliability between the diamond substrate 701 and the heat source, solder, sintered silver layer, or thermally conductive interface material, and to reduce the interfacial contact thermal resistance.

[0076] The diamond substrate 701 is connected to the first NiAu layer 501 using an AuSn welding process. Specifically, an AuSn preform, AuSn plating, or AuSn solder layer is placed between the first NiAu layer 501 and the diamond substrate 701 to form an AuSn solder layer 601. Subsequently, the aligned lower cover plate 200, copper-diamond composite material layer, metal thin layer 401, first NiAu layer 501, AuSn solder layer 601, and diamond substrate 701 are placed in a vacuum reflow oven, hot press welding equipment, or atmosphere-protected welding equipment. Under a vacuum or nitrogen protective atmosphere, the temperature is raised above the melting point of the AuSn solder, causing the AuSn solder layer 601 to melt and wet the first NiAu layer 501 and the first metallization layer on the surface of the diamond substrate 701. After holding at this temperature for 3 to 20 minutes, the substrate is cooled to form a reliable welded connection. Preferably, during the AuSn welding process, the vacuum level is less than or equal to 1×10^-3 Pa, the applied pressure is 0.5MPa to 2MPa, the temperature is raised to 280℃ to 320℃, held for 5 to 20 minutes, and then slowly cooled to room temperature at a rate of less than or equal to 2℃ / min to reduce residual thermal stress from the welding. Through the above process, the AuSn solder layer 601 can form a metal connection interface with low porosity, high thermal conductivity, and high reliability between the first NiAu layer 501 and the diamond substrate 701.

[0077] In this embodiment, the lower cover plate 200 serves as a thermally conductive metal layer with a coefficient of thermal expansion of 15ppm / K to 18ppm / K, a thermal conductivity of 300W / (m·K) to 400W / (m·K), and a Young's modulus of 60GPa to 130GPa. The copper-diamond composite material layer has a coefficient of thermal expansion of 4ppm / K to 10ppm / K, a thermal conductivity of 400W / (m·K) to 900W / (m·K), and a Young's modulus of 150GPa to 600GPa. The diamond substrate 701 has a coefficient of thermal expansion of 0.8ppm / K to 1.5ppm / K, a thermal conductivity of 1000W / (m·K) to 2200W / (m·K), and a Young's modulus of 800GPa to 1200GPa. Thus, the heat diffusion plate composite device forms a gradient composite structure with a progressively decreasing coefficient of thermal expansion and a progressively increasing Young's modulus from the cooling medium side to the chip heat source side.

[0078] In this embodiment, the cooling medium enters the storage chamber 004 through the inlet 003 and is sprayed onto the heat exchange structure area (the area of ​​the first boss 201 and the area of ​​the first groove 202) on the lower cover plate 200 through the spray hole 002. Forced convection heat exchange is formed between the top of the first boss 201, the bottom of the first groove 202, and adjacent first bosses 201, absorbing the heat transferred from the heat source through the second NiAu layer 801, the diamond substrate 701, the first metallization layer, the AuSn solder layer 601, the first NiAu layer 501, the metal thin layer 401, the copper-diamond composite material layer, and the lower cover plate 200. The cooled medium after heat exchange is collected in the return channel 005 and discharged through the outlet 001.

[0079] With the above structure, the diamond substrate 701 is positioned close to the heat source, enabling rapid lateral diffusion of localized hot spots. The copper-diamond composite material layer, located between the lower cover plate 200 and the diamond substrate 701, balances high thermal conductivity, low coefficient of thermal expansion, and high Young's modulus. The metal thin layer 401, the first NiAu layer 501, the first metallization layer, and the AuSn solder layer 601 are used to achieve reliable metallization connections. The connection structure 101 is used to withstand the assembly preload of the upper cover plate 000, the pressure of the cooling medium, and the jet impact load, and improves the overall rigidity of the heat diffusion plate composite device through its support function. Therefore, this embodiment avoids the problems of increased thermal resistance and reduced heat dissipation capacity caused by excessively thick pure copper base plates, and also avoids the problems of insufficient structural strength, deformation, and sealing failure caused by excessively thin pure copper base plates, thereby improving the heat dissipation performance and long-term reliability of the liquid-cooled radiator.

[0080] Example 2

[0081] like Figure 2As shown, the difference between the heat diffusion plate composite device in this embodiment and that in Embodiment 1 is that: multiple second protrusions 302 are provided on the cooling medium side of the metal-diamond composite material layer 301, which cooperate with the first groove 202 on the lower cover plate 200 to form a heat exchange structure region for enhanced spraying; the first groove 202 of the lower cover plate 200 is a through groove that extends along the thickness direction, and the aforementioned first protrusion 201 is formed between two adjacent first grooves 202; the second protrusion 302 is provided on the cooling medium side of the metal-diamond composite material layer 301, the metal-diamond composite material layer 301 is composited on the chip heat source side of the lower cover plate 200 and the second protrusion 302 is inserted into the first groove 202, and a second groove is formed between the first protrusion 201 and the second protrusion 302. Multiple third grooves 303 are provided on the chip heat source side of the metal-diamond composite material layer 301, and multiple third protrusions 702 are provided on the cooling medium side of the diamond substrate 701. The third grooves 303 and the third protrusions 702 cooperate with each other to form a mechanical interlocking structure, thereby enhancing the jet heat dissipation capability and improving the reliability of the welding interface connection. The heat diffusion plate composite device of this embodiment includes, from top to bottom, a connection structure 101, a thermally conductive metal layer, a metal-diamond composite material layer 301, a metal thin layer 401, a first NiAu layer 501, an AuSn solder layer 601, a first metallization layer, a diamond substrate 701, and a second NiAu layer 801. The metal thin layer 401 is provided with through holes adapted to the third protrusions 702, and the third protrusions 702 pass through the through holes.

[0082] In this embodiment, the heat dissipation device uses a heat diffusion plate composite device in conjunction with a jet radiator, but this is not a limitation. The heat diffusion plate composite device can also be assembled or welded to a toothed radiator, a parallel channel radiator, or other liquid cooling structures via a connecting structure 101. A flow channel for the cooling medium is formed between adjacent heat dissipation teeth, and the cooling medium exchanges heat with the thermally conductive metal layer through the flow channel.

[0083] In this embodiment, the lower cover plate 200 is made of oxygen-free copper with a thickness of 1.5 mm; the upper cover plate 000 is made of a metal material with a thermal expansion coefficient matching that of the lower cover plate 200, with a thickness of 5 mm. The connecting structure 101 is made of oxygen-free copper and is a frustum-shaped connecting structure with a height of 3.3 mm, an upper diameter of 2.5 mm, a lower diameter of 2.78 mm, and a sidewall slope of 3°. The liquid storage cavity 004 is a hollow layer of 70 mm × 48 mm × 1 mm. The injection hole 002 is a hollow structure with an upper conical and lower cylindrical shape, wherein the upper diameter of the upper conical section is 0.6 mm, the lower diameter is 0.3 mm, and the height is 1 mm, and the lower cylindrical section has a diameter of 0.3 mm and a height of 1 mm. The reflux groove 005 is a strip channel of 45 mm × 1 mm × 0.5 mm.

[0084] The metal-diamond composite layer 301 is made of copper-diamond composite material and has a thickness of 1 mm; the metal thin layer 401 is made of copper and has a thickness of 0.1 mm; the first NiAu layer 501 and the second NiAu layer 801 both include a nickel layer and a gold layer, wherein the nickel layer has a thickness of 0.5 μm and the gold layer has a thickness of 0.2 μm; the AuSn solder layer 601 has a thickness of 100 μm; and the diamond substrate 701 has a thickness of 0.3 mm. The diamond substrate 701 is oriented towards the heat source and is used to form a thermally conductive connection with the chip, package cover, or power device.

[0085] In the preparation method of the heat dissipation device in this embodiment, the connecting structure 101, the first boss 201, the first groove 202, the second boss 302 and the third groove 303 on the metal-diamond composite material layer 301, and the third boss 702 on the diamond substrate 701 can all be formed by milling, micro-milling, ultra-precision cutting, laser processing, electrical discharge machining, electrochemical machining, micro-electroforming, stamping or die casting, or other micro-machining processes.

[0086] Multiple connecting structures 101 are spaced apart along the cooling medium side of the lower cover plate 200 and protrude towards the upper cover plate 000, serving to achieve mechanical fixation, positioning connection, and stress isolation after the upper and lower cover plates are assembled. Multiple first bosses 201 are arranged between adjacent connecting structures 101, forming a first groove 202 between adjacent first bosses 201. The second bosses 302 on the metal-diamond composite material layer 301 are arranged vertically corresponding to the first grooves 202 on the lower cover plate 200, together forming the enhanced jet heat exchange structure area.

[0087] The upper cover plate 000 is formed with an inlet 003, a jet hole 002, a liquid storage chamber 004, a reflux groove 005, and an outlet 001 through processes such as drilling, milling, laser processing, micro-electroforming, etching, or precision stamping. Among them, the inlet 003 is connected to the liquid storage chamber 004, and the jet hole 002 is set at the bottom of the liquid storage chamber 004, corresponding to the second protrusion 302 on the metal-diamond composite material layer 301 and the first groove 202 on the lower cover plate 200, so that the cooling medium can be directly sprayed to the enhanced heat exchange structure area.

[0088] The upper cover plate 000 and the lower cover plate 200 are then positioned using positioning holes, positioning pins, cross alignment marks, or precision fixtures, ensuring that the injection hole 002 accurately aligns with the second protrusion 302 on the metal-diamond composite material layer 301 and the first groove 202 on the lower cover plate 200. Subsequently, vacuum brazing, diffusion welding, laser welding, electron beam welding, thermosetting bonding, or solid-state diffusion bonding processes are used to achieve a sealed connection between the upper cover plate 000 and the lower cover plate 200.

[0089] Subsequently, a copper-diamond composite material layer is connected to the chip heat source side of the lower cover plate 200. Specifically, the surface of the chip heat source side and the copper-diamond composite material layer of the lower cover plate 200 is first subjected to deoxidation, degreasing, roughening, activation and drying treatment; then, the copper-diamond composite material layer is connected to the chip heat source side of the lower cover plate 200 through vacuum brazing, thermocompression welding, diffusion welding, transient liquid phase bonding or Ag sintering bonding processes.

[0090] Subsequently, a plurality of third protrusions 702 are formed on the side of the diamond substrate 701 facing the metal-diamond composite layer 301. The plurality of third protrusions 702 are corresponding one-to-one with a plurality of third grooves 303 on the lower surface of the metal-diamond composite layer 301, and the third protrusions 702 are embedded in the corresponding third grooves 303 to form a mechanical interlocking structure. Preferably, the third protrusions 702 can be rectangular, trapezoidal, cylindrical, hemispherical, serrated, or other regular or irregular protrusion structures, and the structure of the third grooves 303 matches the third protrusions 702 to ensure positioning accuracy and interface bonding stability after assembly.

[0091] A thin metal layer 401 is formed on the side of the copper-diamond composite material layer away from the lower cover plate 200. The thin metal layer 401 can be formed by electroplating, chemical plating, magnetron sputtering, vapor deposition, thermal spraying, cold spraying, or rolling composite methods. Preferably, the copper thin layer is formed by electroplating copper or sputtering thickened copper process, so that the surface of the thin metal layer 401 is flat and has good solderability. After the thin metal layer 401 is formed, the surface of the thin metal layer 401 is ground or polished to make its flatness less than or equal to 50 μm, so as to improve the bonding quality of the subsequent welding interface.

[0092] A first NiAu layer 501 is prepared on the surface of the metal thin layer 401. Specifically, a nickel layer and a gold layer are sequentially formed on the surface of the metal thin layer 401 by chemical plating, electroplating, sputtering, or vapor deposition. The nickel layer acts as a diffusion barrier layer to suppress excessive element diffusion between the metal thin layer 401 and the AuSn solder layer 601; the gold layer acts as a solder wetting layer to improve the wettability and interfacial bonding strength of the AuSn solder layer 601 during the soldering process.

[0093] Subsequently, the diamond substrate 701 undergoes double-sided metallization. A first metallization layer is formed on the side of the diamond substrate 701 facing the metal-diamond composite layer 301, and a second NiAu layer 801 is formed on the side of the diamond substrate 701 facing the heat source. Specifically, the first metallization layer can be formed into a Ti / Pt / Au, Ti / Ni / Au, Cr / Au, or Cr / Ni / Au structure through magnetron sputtering, evaporation, or other thin film deposition processes; the second NiAu layer 801 can be formed into a nickel layer and a gold layer sequentially through chemical plating, electroplating, sputtering, or evaporation processes. The nickel layer is used to improve the bonding strength between the metal layer and the diamond and acts as a diffusion barrier layer to suppress the diffusion of interfacial elements; the gold layer is used to improve the wetting performance of the AuSn solder, reduce the contact thermal resistance at the welding interface, and improve the reliability of the weld connection.

[0094] After surface metallization, AuSn preformed solder pads, AuSn solder paste, AuSn plating, or other AuSn solder are placed between the first NiAu layer 501 and the first metallization layer to form an AuSn solder layer 601. Subsequently, the lower cover plate 200, the metal-diamond composite material layer 301, the metal thin layer 401, the first NiAu layer 501, the AuSn solder layer 601, and the diamond substrate 701 are assembled sequentially. A positioning fixture is used to ensure that the third protrusion 702 on the diamond substrate 701 accurately corresponds to the third groove 303 on the metal-diamond composite material layer 301, so that the third protrusion 702 can be embedded in the corresponding third groove 303 to form a mechanical interlocking structure.

[0095] Preferably, the assembled structure is placed in a vacuum reflow oven, hot press welding equipment, or atmosphere-protected welding equipment, and heated to above the melting point of AuSn solder under a vacuum or nitrogen protective atmosphere. This melts the AuSn solder layer 601 and fully wets the surface of the first NiAu layer 501 and the first metallization layer, while simultaneously filling the space between the third boss 702 and the third groove 303 to form a continuous welding interface. After holding at this temperature for a predetermined time, it is slowly cooled to solidify the AuSn solder layer 601 and form a reliable metallurgical bonding interface. Preferably, during the AuSn welding process, the vacuum degree is no greater than 1×10^-3 Pa, the applied pressure is 0.5MPa~2MPa, the welding temperature is 280℃~320℃, the holding time is 5min~20min, and then it is slowly cooled to room temperature at a rate no greater than 2℃ / min to reduce residual thermal stress from welding and improve the uniformity of the weld interface structure and the reliability of the connection.

[0096] Because the third boss 702 on the diamond substrate 701 is embedded in the third groove 303 on the metal-diamond composite layer 301, during the AuSn welding process, the molten solder not only forms a continuous metallurgical bonding interface but also fills the gap between the third boss 702 and the third groove 303, resulting in a composite connection structure combining metallurgical bonding and mechanical interlocking at the welding interface. Compared to traditional planar welding interfaces, this mechanical interlocking structure effectively increases the effective bonding area of ​​the welding interface, increases the contact area and bonding area between the solder and the substrates on both sides, and restricts the relative slippage of the welding interface. This allows the interface load to be transferred from the plane to both the boss sidewall and the groove sidewall, reducing interface stress concentration and improving the shear strength, peel resistance, and fatigue resistance of the welding interface. Consequently, it improves the welding connection strength and long-term service reliability between the metal-diamond composite layer 301 and the diamond substrate 701.

[0097] In this embodiment, the lower cover plate 200 serves as a thermally conductive metal layer with a coefficient of thermal expansion of 15ppm / K to 18ppm / K, a thermal conductivity of 300W / (m·K) to 400W / (m·K), and a Young's modulus of 60GPa to 130GPa. The copper-diamond composite material layer has a coefficient of thermal expansion of 4ppm / K to 10ppm / K, a thermal conductivity of 400W / (m·K) to 900W / (m·K), and a Young's modulus of 150GPa to 600GPa. The diamond substrate 701 has a coefficient of thermal expansion of 0.8ppm / K to 1.5ppm / K, a thermal conductivity of 1000W / (m·K) to 2200W / (m·K), and a Young's modulus of 800GPa to 1200GPa. Thus, the heat diffusion plate composite device forms a gradient composite structure with a progressively decreasing coefficient of thermal expansion and a progressively increasing Young's modulus from the cooling medium side to the chip heat source side.

[0098] The working process of this embodiment is as follows: The cooling medium enters the liquid storage chamber 004 through the inlet 003, forms a high-speed liquid jet through the spray hole 002, and is directly sprayed onto the enhanced heat exchange structure area composed of the second protrusion 302 on the upper surface of the metal-diamond composite material layer 301 and the first groove 202 on the lower cover plate 200. Since the metal-diamond composite material layer 301 has a high thermal conductivity, heat can be quickly transferred to its surface. The liquid jet acts directly on the surface of the metal-diamond composite material layer 301, which can reduce the heat transfer path of heat to the cooling medium through the lower cover plate, reduce the conduction thermal resistance, and reduce the thermal conductivity. Meanwhile, multiple second protrusions 302 divert the liquid jet, forming local high-speed flow and vortex structures between adjacent second protrusions 302, continuously disrupting the fluid boundary layer, enhancing the turbulence of the cooling medium, and improving the local convective heat transfer coefficient; the first groove 202 on the lower cover plate 200 can induce local backflow and secondary flow, enhance fluid mixing and increase the effective heat transfer area, so that the cooling medium forms sufficient three-dimensional enhanced convective heat transfer between the top of the protrusion 302, the bottom of the first groove 202 and the adjacent second protrusions 302, thereby improving the overall heat dissipation performance of the heat diffuser plate.

[0099] The heat generated by the heat source is sequentially transferred to the cooling medium through the second NiAu layer 801, the diamond substrate 701, the first metallization layer, the AuSn solder layer 601, the first NiAu layer 501, the metal thin layer 401, the metal-diamond composite material layer 301, and the lower cover plate 200. The cooling medium after heat exchange is collected through the return tank 005 and finally discharged from the outlet 001, realizing continuous circulation heat dissipation.

[0100] Compared to Embodiment 1, this embodiment provides multiple second protrusions 302 on the upper surface of the metal-diamond composite material layer 301, which, together with the first groove 202 on the lower cover plate 200, form a heat exchange structure region for enhanced jetting. This allows the liquid jet to directly act on the surface of the metal-diamond composite material layer 301, which has higher thermal conductivity, shortening the path of heat transfer from the interior of the material to the cooling medium, enhancing fluid turbulence and local convection heat transfer capabilities, and improving jet heat dissipation efficiency. Simultaneously, multiple third grooves 303 are provided on the lower surface of the metal-diamond composite material layer 301, forming a mechanically interlocked welding structure with multiple third protrusions 702 on the diamond substrate 701. This transforms the welding interface from a traditional planar connection to a three-dimensional interlocked connection, not only increasing the effective bonding area of ​​the interface but also enhancing the shear resistance, peel resistance, and fatigue resistance of the welding interface, further improving the connection reliability between the metal-diamond composite material layer 301 and the diamond substrate 701.

[0101] In summary, this embodiment achieves enhanced heat transfer structure and mechanically interlocked welding structure on both sides of the metal-diamond composite material layer 301, while maintaining a gradient transition of the coefficient of thermal expansion. This results in synergistic optimization of enhanced jet cooling, highly reliable welding connection, and thermal management performance, effectively improving the heat dissipation capacity, structural reliability, and long-term service stability of the liquid cooler. Therefore, this embodiment is suitable for heat dissipation applications of electronic devices with high heat flux density chips, power semiconductor devices, and advanced electronic packaging, where heat dissipation performance and connection reliability are critical.

[0102] The above description is merely a preferred embodiment of the present invention, and therefore should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the patent and the contents of the specification should still fall within the scope of the present invention.

Claims

1. A heat diffusion plate composite device, characterized in that: The device comprises a thermally conductive metal layer, a metal-diamond composite material layer, and a diamond substrate layer that are compositely connected together. In the thickness direction, the thermally conductive metal layer, the metal-diamond composite material layer, and the diamond substrate layer are arranged sequentially from the cooling medium side to the chip heat source side. The cooling medium side of the thermally conductive metal layer is provided with a heat exchange structure region and an outwardly protruding connection structure. The diamond substrate layer faces the chip heat source and receives heat.

2. The heat diffusion plate composite device according to claim 1, characterized in that: The coefficients of thermal expansion of the thermally conductive metal layer, the metal-diamond composite material layer, and the diamond substrate decrease layer by layer, while the thermal conductivity and Young's modulus of the thermally conductive metal layer, the metal-diamond composite material layer, and the diamond substrate increase layer by layer.

3. The heat diffusion plate composite device according to claim 1, characterized in that: A thin metal layer is provided between the metal-diamond composite material layer and the diamond substrate.

4. The heat diffusion plate composite device according to claim 3, characterized in that: A welding layer is provided between the diamond substrate and the metal thin layer; the welding layer includes one of AuSn solder layer, SnAg solder layer, In-based solder layer or Ag sintered layer.

5. The heat diffusion plate composite device according to claim 3, characterized in that: The chip heat source side of the metal thin layer is provided with a first NiAu layer; the first NiAu layer includes a nickel layer and a gold layer, the nickel layer serves as a diffusion barrier layer, and the gold layer serves as a solder wetting layer.

6. The heat diffusion plate composite device according to claim 1, characterized in that: The diamond substrate has a first metallization layer on the cooling medium side; the first metallization layer is one of Ti / Pt / Au, Ti / Ni / Au, Cr / Au or Cr / Ni / Au.

7. The heat diffusion plate composite device according to claim 1, characterized in that: The diamond substrate has a second metallization layer on the chip heat source side, which is a second NiAu layer. The second NiAu layer includes a nickel layer and a gold layer, wherein the nickel layer serves as a diffusion barrier layer and the gold layer serves as a solder wetting layer.

8. The heat diffusion plate composite device according to claim 3, characterized in that: The connecting structure is columnar, and the height of the columnar structure is 1mm to 10mm. The thermally conductive metal layer is a copper material layer or an aluminum material layer, and the thickness of the thermally conductive metal layer is 0.1mm to 3mm; The metal-diamond composite material layer is a copper-diamond composite material layer, an aluminum-diamond composite material layer, or a silver-diamond composite material layer, and the thickness of the metal-diamond composite material layer is 0.1 mm to 2 mm; The thickness of the metal thin layer is 0.01 mm to 0.2 mm.

9. The heat diffusion plate composite device according to claim 1, characterized in that: The heat exchange structure region includes a first groove and a first boss located on the cooling medium side of the heat-conducting metal layer.

10. The heat diffusion plate composite device according to claim 9, characterized in that: The first groove is a through groove that extends along the thickness direction, and the first protrusion is formed between adjacent first grooves; the cooling medium side of the metal-diamond composite material layer is provided with a second protrusion, the metal-diamond composite material layer is composited on the chip heat source side of the thermally conductive metal layer and the second protrusion is inserted into the first groove, and a second groove is formed between the second protrusion and the first protrusion.

11. The heat diffusion plate composite device according to claim 1, characterized in that: The chip heat source side of the metal-diamond composite material layer is recessed with a third groove, and the cooling medium side of the diamond substrate is protruded with a third protrusion, which is adapted to be inserted into the third groove.

12. The heat diffusion plate composite device according to claim 11, characterized in that: A thin metal layer is provided between the metal-diamond composite material layer and the diamond substrate, and the thin metal layer has a through hole adapted to the third boss, through which the third boss passes.

13. A heat diffusion plate composite device, characterized in that: The device comprises a thermally conductive metal layer and a metal-diamond composite material layer bonded together. The thermally conductive metal layer and the metal-diamond composite material layer are arranged sequentially from the cooling medium side to the chip heat source side in the thickness direction. The cooling medium side of the thermally conductive metal layer is provided with a heat exchange structure region and an outwardly protruding connection structure. The metal-diamond composite material layer faces the chip heat source and receives heat.

14. A heat diffusion plate composite device, characterized in that: The chip comprises a first layer, a second layer, and a third layer that are compositely connected together. In the thickness direction, the first layer, the second layer, and the third layer are arranged sequentially from the cooling medium side to the chip heat source side. The coefficient of thermal expansion of the first layer, the second layer, and the third layer decreases layer by layer, while the Young's modulus and thermal conductivity of the first layer, the second layer, and the third layer increase layer by layer. The cooling medium side of the first layer is provided with a heat exchange structure area and an outwardly protruding connection structure. The third layer faces the heat source and receives heat.

15. The heat diffusion plate composite device according to claim 14, characterized in that: The first layer has a thermal expansion coefficient of 15ppm / K to 25ppm / K, the second layer has a thermal expansion coefficient of 4ppm / K to 12ppm / K, and the third layer has a thermal expansion coefficient of 0.8ppm / K to 3ppm / K; the first layer has a Young's modulus of 60GPa to 130GPa, the second layer has a Young's modulus of 150GPa to 600GPa, and the third layer has a Young's modulus of 800GPa to 1200GPa; the first layer has a thermal conductivity of 150W / (m·K) to 400W / (m·K), the second layer has a thermal conductivity of 400W / (m·K) to 900W / (m·K), and the third layer has a thermal conductivity of 1000W / (m·K) to 2200W / (m·K).

16. The heat diffusion plate composite device according to claim 14, characterized in that: The first layer is a thermally conductive metal layer or a first metal-diamond composite material layer, the second layer is a second metal-diamond composite material layer, and the third layer is a diamond substrate or a third metal-diamond composite material layer.

17. A heat dissipation device, including a radiator, characterized in that: It also includes the heat diffusion plate composite device according to claim 1, wherein the heat sink is fixed on the cooling medium side of the heat-conducting metal layer and the heat sink is matched with the heat exchange structure area of ​​the heat-conducting metal layer.

18. The heat dissipation device according to claim 17, characterized in that: The connecting structure is columnar, and the surface of the heat sink facing the heat diffusion plate composite device is provided with a connecting groove; the connecting structure and the connecting groove are adapted to each other.

19. The heat dissipation device according to claim 17, characterized in that: The heat sink is a jet heat sink, which includes an upper cover plate, a liquid storage chamber inside the upper cover plate, an outlet and an inlet on the cooling medium side of the upper cover plate, a jet hole and a return groove on the chip heat source side of the upper cover plate, the inner ends of the inlet and the jet hole are connected to the liquid storage chamber, and the return groove is connected to the outlet; the outer end of the jet hole faces the heat exchange structure area. The cooling medium enters the storage chamber through the inlet and is sprayed towards the heat exchange structure area through the spray holes for heat exchange, and then flows out through the return tank and the outlet.

20. The heat dissipation device according to claim 17, characterized in that: The radiator is a toothed radiator, which includes multiple staggered cooling teeth, with flow channels formed between adjacent cooling teeth for the cooling medium to circulate.

21. The method for preparing the heat dissipation device according to claim 17, characterized in that: include: A thermally conductive metal layer and a heat sink are fabricated, wherein the thermally conductive metal layer has a connection structure and a heat exchange structure region; The thermally conductive metal layer and the heat sink are connected together; A metal-diamond composite material layer is compositely connected to the heat source side of the thermally conductive metal layer; A thin metal layer is compositely bonded to the chip heat source side of the metal-diamond composite layer, and a first NiAu layer is prepared on the chip heat source side of the thin metal layer; The surface of the diamond substrate is metallized on the cooling medium side, and the diamond substrate is connected to the first NiAu layer of the metal thin layer through a welding layer.

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