Copper-based diamond composite material and preparation method and application thereof

Abstract

The present application relates to the technical field of electronic packaging thermal management materials, and particularly relates to a copper-based diamond composite material and a preparation method and application thereof. The copper-based diamond composite material comprises a continuous matrix composed of copper or a copper alloy, and diamond composite particles uniformly dispersed in the matrix; the diamond composite particles comprise diamond particles, a liquid metal layer coated on the surface of the diamond particles, and a metal plating layer coated outside the liquid metal layer; and the surface of the diamond particles is subjected to plasma activation treatment. The copper-based diamond composite material provided by the present application has a thermal expansion coefficient controllable within 7.5-9.0 ppm, a thermal conductivity reaching 695 W / (m*K) or above, and a bending strength of 320 MPa or above, and can be applied in the preparation of high-power electronic device heat dissipation substrates or electronic packaging carriers.

Description

Technical Field

[0001] This invention relates to the field of electronic packaging thermal management materials technology, and in particular to a copper-based diamond composite material, its preparation method and application. Background Technology

[0002] With the advancement of science and technology, the development of electronic components is rapidly moving towards higher density, higher power, and miniaturization. Consequently, the heat generated during the operation of these components is increasing dramatically, leading to higher operating temperatures for high-performance electronic components. This increased temperature significantly reduces the lifespan and efficiency of chips. Currently, heat dissipation is one of the technological bottlenecks facing the development of the electronic information industry. This is especially true in high-tech fields where high-power devices are typical applications, creating a more urgent need for advanced heat dissipation materials. Therefore, the development of novel thermal management materials with high thermal conductivity has become a key technology for improving the performance and reliability of electronic components.

[0003] Traditional electronic packaging materials mainly consist of tungsten-copper alloys and molybdenum-copper alloys. For example, Chinese invention patent application CN119307762A provides a dual-morphology, fully dense tungsten-copper alloy electronic packaging heat sink material. However, these materials all have corresponding problems in current electronic applications. For instance, although tungsten-copper alloys and molybdenum-copper alloys have low coefficients of thermal expansion that match silicon-based chips, the thermal conductivity of these two alloys is only 200 W·m. -1 ·K -1 Insufficient thermal conductivity and a relatively large proportion of oxygen-free copper are gradually failing to meet the needs of mobile devices and aerospace applications. Third-generation electronic packaging materials, represented by silicon carbide / aluminum (SiC / Al) and silicon / aluminum (Si / Al) composite materials, have adjustable coefficients of thermal expansion (e.g., Chinese invention patent application CN103966542A), but their thermal conductivity is lower than that of oxygen-free copper, which cannot meet the requirements in the field of high-power semiconductor device packaging.

[0004] Diamond is one of the most thermally conductive substances in nature, with single-crystal diamond having a thermal conductivity five times that of copper (up to 2000 W·m). -1 ·K -1 Its application in the field of thermal conductivity and heat dissipation has significant advantages. Fourth-generation electronic packaging materials, represented by copper-diamond composites, have become a research and development hotspot. However, due to the poor interfacial wettability between diamond and metal, the bonding effect of copper-diamond composite interface components is very poor, thus affecting the overall thermal conductivity of the material.

[0005] Therefore, optimizing the interfacial bonding between diamond and the metal matrix has become a key factor in improving the thermal conductivity of composite materials. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the first aspect of the present invention provides a copper-based diamond composite material, comprising a continuous matrix composed of copper or a copper alloy, and diamond composite particles uniformly dispersed in the matrix. The diamond composite particles include diamond particles, a liquid metal layer covering the surface of the diamond particles, and a metal coating covering the liquid metal layer. The surface of the diamond particles is subjected to plasma activation treatment; the process conditions for plasma activation treatment are: vacuum degree 1-100Pa, power 100-400W, gas flow rate 10-100sccm, and treatment time 5-30min.

[0007] Poor wettability at the diamond-coated copper matrix interface leads to poor interfacial bonding and high thermal resistance, severely limiting the overall thermal conductivity of the composite material. Existing technologies improve wettability by coating the diamond surface with metal layers such as tungsten or molybdenum, but this easily introduces interfacial stress; alternatively, vacuum pressure infiltration is used to prepare porous framework structures, but this results in uneven bonding between the framework and the copper matrix and poor matching of thermal expansion coefficients.

[0008] In this invention, the surface of diamond particles is first subjected to plasma activation treatment. Plasma bombardment removes oxides and contaminants from the diamond surface through high-energy particle etching, while simultaneously generating active groups such as CO and CN on the surface, significantly increasing the surface energy and providing a physicochemical basis for uniform wetting of the liquid metal. Then, a liquid metal layer and a metal coating are sequentially coated onto the surface of the diamond particles. Through this unique multi-layer coating structure design, the liquid metal layer can form a uniform and stable wetting interface on the diamond particle surface, while the metal coating further enhances the metallurgical bonding ability with the copper matrix. This structure not only significantly improves the interfacial bonding strength between diamond and the copper matrix but also effectively reduces the interfacial thermal resistance, thereby greatly improving the overall thermal conductivity of the composite material.

[0009] In some embodiments, the gas used for the plasma activation treatment is selected from at least one of argon, hydrogen, and nitrogen.

[0010] In some embodiments, the liquid metal layer comprises a gallium-based alloy.

[0011] Optionally, the gallium-based alloy is selected from one or more of pure gallium, gallium-indium alloy, gallium-tin alloy, gallium-zinc alloy, gallium-indium-tin alloy, gallium-indium-zinc alloy, or gallium-indium-tin-zinc alloy.

[0012] In some embodiments, the liquid metal layer further comprises 0.1-2.0% by mass of an active metal from a gallium-based alloy; the active metal is selected from at least one of titanium, chromium, and zirconium.

[0013] The active metal components added to the liquid metal layer can react with carbon atoms on the diamond surface to generate nanoscale carbides, forming a chemically bonded transition layer, which further enhances the interfacial bonding effect and significantly reduces the interfacial thermal resistance.

[0014] In some embodiments, the metal coating satisfies at least one of the following conditions: A. The material of the metal plating layer is selected from one or more of copper, silver, nickel, chromium, and gold; B. The thickness of the metal coating is 0.1-5μm.

[0015] In some embodiments, the mass fraction of the diamond composite particles in the copper-based diamond composite material is 60-75%. Examples include 60%, 65%, 70%, 75%, or any value within the range of 60-75%.

[0016] A second aspect of the present invention provides a method for preparing a copper-based diamond composite material, comprising at least the following steps: S1. The diamond particles are subjected to plasma activation treatment to obtain surface-activated diamond particles. S2. The surface-activated diamond particles are mixed and stirred with liquid metal under vacuum or protective atmosphere to obtain diamond particles coated with a liquid metal layer. S3. Perform metal plating treatment on the diamond particles coated with the liquid metal layer to obtain diamond composite particles. S4. The diamond composite particles are uniformly mixed with copper or copper alloy powder to obtain a mixture. The mixture is then subjected to vacuum hot pressing sintering to obtain the copper-diamond composite material.

[0017] In some embodiments, the preparation method satisfies at least one of the following conditions: A. The mixing speed in S2 is not less than 2000 rad / min, the mixing time is 10-60 minutes, and / or the mixing is carried out under ultrasonic assistance with an ultrasonic power of 100-500W. B. After S2 and before S3, the process further includes a low-temperature heat treatment step on the liquid metal modified diamond particles, wherein the temperature of the low-temperature heat treatment is 200-500℃ and the time is 10-60min.

[0018] This invention involves performing a vacuum heat treatment at 200-500℃ for 10-60 minutes after liquid metal modification and before metal plating. This low-temperature heat treatment accelerates atomic diffusion at the interface between the liquid metal and diamond, promoting the homogenization of the carbide layer and eliminating micropores; simultaneously, it inhibits the oxidation of gallium-based alloys, forming more continuous heat-conducting channels and further improving thermal conductivity.

[0019] In some embodiments, the method for treating the metal coating is selected from one of chemical plating, electroplating, magnetron sputtering, and thermal evaporation.

[0020] In some embodiments, S4 includes: uniformly mixing the diamond composite particles with copper or copper alloy powder to obtain a mixture, placing the mixture into a corresponding copper frame, covering it with copper cover plates on the top and bottom, and performing vacuum hot pressing sintering to obtain the copper-diamond composite material.

[0021] Optionally, the materials of the copper frame and the copper cover plate are selected from at least one of T1, T2, T3, T4, TU1, TU2, TUP, and TUMn.

[0022] In some embodiments, the conditions for vacuum hot pressing sintering are: vacuum degree ≤ 1 × 10⁻⁶ -2 Pa, sintering temperature 750-1200℃, pressure 20-65MPa, holding time 15-90min.

[0023] The third aspect of this invention provides an application of copper-based diamond composite material in the preparation of heat dissipation substrates or electronic packaging carriers for high-power electronic devices.

[0024] Beneficial effects: This invention provides a copper-based diamond composite material, its preparation method, and its application, which have the following advantages: (1) In this invention, the surface of diamond particles is first subjected to plasma activation treatment, and then a liquid metal layer and a metal coating are sequentially coated on the surface of diamond particles, which significantly improves the interfacial bonding strength between diamond and copper matrix and effectively reduces interfacial thermal resistance, thereby greatly improving the overall thermal conductivity of composite material.

[0025] (2) By synergistically controlling the mass fraction of diamond composite particles and the coating metal, the thermal expansion coefficient of the present invention can be controlled at 7.5-9.0ppm, the thermal conductivity reaches 695W / (m·K) or above, and the bending strength is above 320MPa.

[0026] (3) The copper-based diamond composite material provided by the present invention is easy to process and form, providing good processing conditions for precision grinding, welding and other processing processes.

[0027] (4) The present invention has a short preparation cycle and a simple process flow, and can be adapted to large-scale mass production. Attached Figure Description

[0028] Figure 1 This is a SEM image of diamond particles coated with a liquid metal layer. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention. Experimental methods not specifying specific conditions in the embodiments were performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials, consumables, and equipment used in this invention are all commercially available.

[0030] Example 1 The first aspect of this example provides a copper-based diamond composite material, comprising a continuous matrix made of copper or a copper alloy, and diamond composite particles uniformly dispersed in the matrix. The diamond composite particles include diamond particles, a liquid metal layer covering the surface of the diamond particles, and a metal coating covering the liquid metal layer. The surface of the diamond particles is subjected to plasma activation treatment; the process conditions for plasma activation treatment are: vacuum degree 10 Pa, power 200 W, gas flow rate 50 sccm, and treatment time 10 min.

[0031] The liquid metal layer is composed of a gallium-indium alloy with a mass ratio of gallium to indium of 75:25.

[0032] The metal coating is made of silver and has a thickness of 0.5 μm.

[0033] The diamond composite particles have a mass fraction of 70% in the copper-based diamond composite material.

[0034] The second aspect of this example provides a method for preparing a copper-based diamond composite material, which includes at least the following steps: S1. Select diamond particles with a particle size of 45-50 mesh, place them in a plasma treatment device, introduce argon gas (flow rate 50 sccm), and treat them for 10 min under a vacuum of 10 Pa and a power of 200 W to obtain surface-activated diamond particles. S2. The surface-activated diamond particles are mixed with gallium indium alloy (EGaIn) at a mass ratio of 5:1 and placed in a vacuum mixer. The mixture is stirred at a speed of 2500 rad / min for 30 min to make the liquid metal uniformly coat the diamond surface, thus obtaining diamond particles coated with a liquid metal layer. S3. The diamond particles coated with the liquid metal layer are placed in a magnetron sputtering device, and a silver target is sputtered to deposit a silver layer with a thickness of 0.5 μm on the surface of the diamond particles to obtain diamond composite particles (the mass of the silver layer accounts for 3% of the total mass of the diamond composite particles). S4. Mix the diamond composite particles and oxygen-free copper powder evenly at a mass ratio of 70:30, pack the mixture into a T1 copper frame, cover it with T1 copper cover plates on the top and bottom, place it in a mold, and sinter it in a vacuum hot press furnace with a vacuum degree of 5×10⁻⁶. -3 The copper-based diamond composite material was obtained by applying a heat treatment method with a temperature of 1050℃, a pressure of 40MPa, and a holding time of 60min, followed by furnace cooling.

[0035] The third aspect of this example provides an application of copper-based diamond composite material in the preparation of heat dissipation substrates or electronic packaging carriers for high-power electronic devices.

[0036] Figure 1 These are diamond particles coated with a liquid metal layer. As can be seen in the image, the diamond surface is uniformly coated with liquid metal. After plasma activation, the wettability is significantly improved, with no obvious pores or unwetted areas.

[0037] The copper-based diamond composite material obtained in this example has a thermal conductivity of 712 W / (m·K), a coefficient of thermal expansion of 8.4 ppm, and a flexural strength of 345 MPa.

[0038] Example 2 The first aspect of this example provides a copper-based diamond composite material, comprising a continuous matrix made of copper or a copper alloy, and diamond composite particles uniformly dispersed in the matrix. The diamond composite particles include diamond particles, a liquid metal layer covering the surface of the diamond particles, and a metal coating covering the liquid metal layer. The surface of the diamond particles is subjected to plasma activation treatment; the process conditions for plasma activation treatment are: vacuum degree 10Pa, power 200W, gas flow rate 50sccm, and treatment time 20min.

[0039] The liquid metal layer is composed of a gallium-indium-tin alloy, with a mass ratio of gallium, indium, and tin of 62:25:13.

[0040] The metal coating is made of nickel and has a thickness of 1 μm.

[0041] The diamond composite particles have a mass fraction of 70% in the copper-based diamond composite material.

[0042] The second aspect of this example provides a method for preparing a copper-based diamond composite material, which includes at least the following steps: S1. Select diamond particles with a particle size of 45-50 mesh, place them in a plasma treatment device, introduce hydrogen gas (flow rate 50 sccm), and treat them for 20 min under a vacuum of 10 Pa and a power of 200 W to obtain surface-activated diamond particles. S2. The surface-activated diamond particles are mixed with gallium indium tin alloy at a mass ratio of 5:1, and titanium powder of 1.2 wt% of the total mass of liquid metal is added. The mixture is placed in a vacuum mixer and stirred at a speed of 2500 rad / min for 30 min to make the liquid metal uniformly coat the diamond surface, thus obtaining diamond particles coated with a liquid metal layer. S3. Perform chemical nickel plating on the diamond particles coated with the liquid metal layer to obtain diamond composite particles (the mass of the nickel layer accounts for 5% of the total mass of the diamond composite particles). S4. Mix the diamond composite particles and oxygen-free copper powder evenly at a mass ratio of 70:30, pack the mixture into a T1 copper frame, cover it with T1 copper cover plates on the top and bottom, place it in a mold, and sinter it in a vacuum hot press furnace with a vacuum degree of 5×10⁻⁶. -3 The copper-based diamond composite material was obtained by applying a heat treatment method with a temperature of 1100℃, a pressure of 35MPa, and a holding time of 45min, followed by furnace cooling.

[0043] The third aspect of this example provides an application of copper-based diamond composite material in the preparation of heat dissipation substrates or electronic packaging carriers for high-power electronic devices.

[0044] The copper-based diamond composite material obtained in this example has a thermal conductivity of 768 W / (m·K), a coefficient of thermal expansion of 7.9 ppm, and a flexural strength of 362 MPa.

[0045] Example 3 The first aspect of this example provides a copper-based diamond composite material, comprising a continuous matrix made of copper or a copper alloy, and diamond composite particles uniformly dispersed in the matrix. The diamond composite particles include diamond particles, a liquid metal layer covering the surface of the diamond particles, and a metal coating covering the liquid metal layer. The surface of the diamond particles is subjected to plasma activation treatment; the process conditions for plasma activation treatment are: vacuum degree 10 Pa, power 200 W, gas flow rate 50 sccm, and treatment time 10 min.

[0046] The liquid metal layer is composed of pure gallium.

[0047] The metal coating is made of copper and has a thickness of 0.3 μm.

[0048] The diamond composite particles have a mass fraction of 70% in the copper-based diamond composite material.

[0049] The second aspect of this example provides a method for preparing a copper-based diamond composite material, which includes at least the following steps: S1. Select diamond particles with a particle size of 35-40 mesh, place them in a plasma treatment device, introduce argon gas (flow rate 50 sccm), and treat them for 5 min under a vacuum of 10 Pa and a power of 200 W to obtain surface-activated diamond particles. S2. The surface-activated diamond particles are mixed with pure gallium at a mass ratio of 5:1 and placed in a vacuum mixer. The mixture is stirred at a speed of 2500 rad / min for 30 min to make the liquid metal uniformly coat the diamond surface, thus obtaining diamond particles coated with a liquid metal layer. S3. The diamond particles coated with the liquid metal layer are placed in a magnetron sputtering device, and a copper target is sputtered to deposit a copper layer with a thickness of 0.3 μm on the surface of the diamond particles to obtain diamond composite particles (the mass of the copper layer accounts for 3% of the total mass of the diamond composite particles). S4. Mix the diamond composite particles and oxygen-free copper powder evenly at a mass ratio of 70:30, pack the mixture into a T1 copper frame, cover it with T1 copper cover plates on the top and bottom, place it in a mold, and sinter it in a vacuum hot press furnace with a vacuum degree of 5×10⁻⁶. -3 The copper-based diamond composite material was obtained by applying a heat treatment method with a temperature of 1050℃, a pressure of 40MPa, and a holding time of 60min, followed by furnace cooling.

[0050] The third aspect of this example provides an application of copper-based diamond composite material in the preparation of heat dissipation substrates or electronic packaging carriers for high-power electronic devices.

[0051] The copper-based diamond composite material obtained in this example has a thermal conductivity of 695 W / (m·K), a coefficient of thermal expansion of 8.9 ppm, and a flexural strength of 328 MPa.

[0052] Example 4 The specific implementation method of this example is the same as that of Example 1, except that a low-temperature heat treatment step is added after S2 and before S3: the diamond particles coated with liquid metal layer are placed in a vacuum furnace, kept at 350°C for 30 minutes, and then cooled naturally.

[0053] The copper-based diamond composite material obtained in this example has a thermal conductivity of 742 W / (m·K), a coefficient of thermal expansion of 8.1 ppm, and a flexural strength of 378 MPa.

[0054] Comparative Example 1 The specific implementation method of this example is the same as that of Example 1, except that step S1 plasma activation treatment is omitted, while the rest of the steps are exactly the same.

[0055] The copper-based diamond composite material obtained in this example has a thermal conductivity of 405 W / (m·K), a coefficient of thermal expansion of 16.8 ppm, and a flexural strength of 150 MPa. Significant voids exist at the interface, indicating poor bonding between the diamond and the copper matrix.

[0056] Comparative Example 2 The specific implementation method of this example is the same as that of Example 1. The difference is that step S2 liquid metal modification is omitted, and the diamond particles are directly magnetron sputtered to be silvered (silver layer thickness 0.5 μm), and then mixed with copper powder and hot-pressed and sintered.

[0057] The copper-based diamond composite material obtained in this example has a thermal conductivity of 218 W / (m·K), a coefficient of thermal expansion of 16.4 ppm, and a flexural strength of 123 MPa. However, the interfacial bonding is poor, resulting in significant diamond exposure.

[0058] Comparative Example 3 The specific implementation method in this example is the same as in Example 1, except that the plasma activation power is reduced from 200W to 50W.

[0059] The copper-based diamond composite material obtained in this example has a thermal conductivity of 441 W / (m·K), a coefficient of thermal expansion of 14.9 ppm, and a flexural strength of 200 MPa. In this example, the diamond surface was not fully wetted by the liquid metal in some areas, and micropores existed at the interface.

[0060] Comparative Example 4 The specific implementation method in this example is the same as in Example 1, except that the plasma activation power is increased to 500W.

[0061] The copper-based diamond composite material obtained in this example has a thermal conductivity of 273 W / (m·K), a coefficient of thermal expansion of 16.7 ppm, and a flexural strength of 156 MPa. The slight graphitization on the diamond surface in this example indicates that excessively high-power plasma bombardment may damage the diamond crystal structure and consequently worsen the interfacial bonding.

[0062] Comparative Example 5 The specific implementation method in this example is the same as in Example 1, except that the plasma activation treatment time is 1 minute.

[0063] The copper-based diamond composite material obtained in this example has a thermal conductivity of 432 W / (m·K), a coefficient of thermal expansion of 15.0 ppm, and a flexural strength of 194 MPa.

Claims

1. A copper-based diamond composite material, characterized in that, It includes a continuous matrix made of copper or copper alloy, and diamond composite particles uniformly dispersed in the matrix. The diamond composite particles include diamond particles, a liquid metal layer covering the surface of the diamond particles, and a metal coating covering the liquid metal layer. The surface of the diamond particles is subjected to plasma activation treatment; the process conditions for plasma activation treatment are: vacuum degree 1-100Pa, power 100-400W, gas flow rate 10-100sccm, and treatment time 5-30min.

2. The copper-based diamond composite material according to claim 1, characterized in that, The liquid metal layer comprises a gallium-based alloy.

3. The copper-based diamond composite material according to claim 2, characterized in that, The liquid metal layer also comprises 0.1-2.0% by mass of an active metal from a gallium-based alloy; the active metal is selected from at least one of titanium, chromium, and zirconium.

4. The copper-based diamond composite material according to claim 1, characterized in that, The metal coating satisfies at least one of the following conditions: A. The material of the metal plating layer is selected from one or more of copper, silver, nickel, chromium, and gold; B. The thickness of the metal coating is 0.1-5μm.

5. The copper-based diamond composite material according to claim 1, characterized in that, The mass fraction of the diamond composite particles in the copper-based diamond composite material is 60-75%.

6. A method for preparing a copper-based diamond composite material according to any one of claims 1-5, characterized in that, At least the following steps are included: S1. The diamond particles are subjected to plasma activation treatment to obtain surface-activated diamond particles. S2. The surface-activated diamond particles are mixed and stirred with liquid metal under vacuum or protective atmosphere to obtain diamond particles coated with a liquid metal layer. S3. Perform metal plating treatment on the diamond particles coated with the liquid metal layer to obtain diamond composite particles. S4. The diamond composite particles are uniformly mixed with copper or copper alloy powder to obtain a mixture. The mixture is then subjected to vacuum hot pressing sintering to obtain the copper-diamond composite material.

7. The method for preparing the copper-based diamond composite material according to claim 6, characterized in that, The preparation method satisfies at least one of the following conditions: A. The mixing speed in S2 is not less than 2000 rad / min, the mixing time is 10-60 minutes, and / or the mixing is carried out under ultrasonic assistance with an ultrasonic power of 100-500W. B. After S2 and before S3, the process further includes a low-temperature heat treatment step on the diamond particles coated with the liquid metal layer, wherein the temperature of the low-temperature heat treatment is 200-500℃ and the time is 10-60min.

8. The method for preparing the copper-based diamond composite material according to claim 6, characterized in that, The method for treating the metal coating is selected from one of the following: chemical plating, electroplating, magnetron sputtering, and thermal evaporation.

9. The method for preparing the copper-based diamond composite material according to claim 6, characterized in that, The conditions for vacuum hot pressing sintering are: vacuum degree ≤ 1×10 -2 Pa, sintering temperature 750-1200℃, pressure 20-65 MPa, holding time 15-90min.

10. The application of the copper-based diamond composite material according to any one of claims 1-6 in the preparation of heat dissipation substrates or electronic packaging carriers for high-power electronic devices.

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