WO2022061834A1 - Copper particle solder paste, and preparation method and sintering method therefor - Google Patents

Copper particle solder paste, and preparation method and sintering method therefor Download PDF

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Publication number
WO2022061834A1
WO2022061834A1 PCT/CN2020/118173 CN2020118173W WO2022061834A1 WO 2022061834 A1 WO2022061834 A1 WO 2022061834A1 CN 2020118173 W CN2020118173 W CN 2020118173W WO 2022061834 A1 WO2022061834 A1 WO 2022061834A1
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WIPO (PCT)
Prior art keywords
solder paste
copper
copper particle
particle solder
copper particles
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PCT/CN2020/118173
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French (fr)
Chinese (zh)
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刘志权
高悦
孙蓉
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深圳先进技术研究院
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Priority to PCT/CN2020/118173 priority Critical patent/WO2022061834A1/en
Publication of WO2022061834A1 publication Critical patent/WO2022061834A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/02—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by mechanical features, e.g. shape
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
    • B23K35/36—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
    • B23K35/40—Making wire or rods for soldering or welding

Definitions

  • the present application relates to the technical field of electronic manufacturing, and in particular, to a copper particle solder paste, a preparation method thereof, and a sintering method.
  • microelectronics technology leads the development of current electronic technology. With the rapid upgrading of electronic technology, the attention of microelectronics packaging technology is increasing day by day. At present, the emergence of third-generation solid-state power semiconductor devices is expected to greatly improve the utilization rate of electric energy while reducing power transmission losses, and can control more power in the same area, which is conducive to the miniaturization of devices.
  • the heating problem brought about by high integration restricts the application of third-generation semiconductors. Due to the mismatch of thermal expansion coefficients, the connection layer between the substrate and the chip is constantly subjected to thermal stress cycles during the operation of the device, while traditional tin (Sn)-based solders often generate heat under such cyclic stress due to their low melting point. Cracking, peeling and other failures.
  • nano-metal solder paste is a new type of packaging material in recent years, which can meet the packaging requirements of "low temperature sintering, high temperature service”.
  • the small size effect of nano-metal materials can promote the diffusion of atoms on the surface of metal particles, enabling welding at a lower temperature, while the size effect of particles in the bulk formed after welding disappears, and the remelting temperature returns to The melting point of the bulk metal ensures the high-temperature reliability of the nano-metal solder paste, so that it can meet the needs of the rapidly developing electronics industry.
  • Elemental copper has excellent thermal conductivity and electrical conductivity, and is cheap, easy to prepare into micro-nano copper particles, and is an ideal low-temperature sintering filler.
  • the copper layer is not easy to be thermally decomposed, which not only hinders the diffusion of copper atoms, but also increases the sintering temperature, which increases the difficulty of low-temperature sintering of copper particles.
  • the main technical problem to be solved by the present application is to provide a copper particle solder paste, a preparation method and a sintering method thereof.
  • a reducing agent to the copper particle solder paste, the copper particle solder paste is prevented from being oxidized during storage and use.
  • a technical solution adopted in the present application is to provide a copper particle solder paste, the solder paste includes copper particles with good dispersibility, a dispersant and a solvent, and also includes a reducing agent, wherein the weight of the reducing agent is The serving is 0.5 to 5 servings.
  • the reducing agent includes at least one of ascorbic acid, copper formate, formic acid, acetic acid and acetone oxime.
  • the particle diameter of the copper particles is 100 to 300 nm.
  • the copper particles are spherical.
  • the dispersing agent includes any one of polyvinylpyrrolidone K30, polyvinylpyrrolidone K90 and polyethylene glycol 1000.
  • the solvent includes at least one of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol 200, 2-amino-2-methyl-propanol and 1-amino-2-propanol.
  • the preparation method includes: dispersing copper particles to obtain copper particles with good dispersibility; Prepare the following raw materials in parts by weight: copper particles with good dispersibility, a dispersant, a solvent and a reducing agent, wherein the weight part of the reducing agent is 0.5 to 5 parts; the reducing agent, the dispersing agent and the solvent are mixed and stirred according to the ratio of the raw materials Evenly, a paste is obtained; the paste is added to the copper particles with good dispersibility according to the raw material ratio and stirred evenly to obtain a copper particle solder paste.
  • the step of dispersing the copper particles to obtain copper particles with good dispersibility specifically includes: preparing the following raw materials according to a preset weight: copper particles, anhydrous ethanol, and a dispersant; The mixture is added into anhydrous ethanol according to the ratio of the raw materials to obtain a mixed liquid; the mixed liquid is ultrasonically dispersed for at least 30 minutes to obtain a dispersion; the dispersion is vacuum-dried to obtain copper particles with good dispersibility.
  • the step of vacuum-drying the dispersion to obtain copper particles with good dispersibility further includes: controlling the degree of vacuum to be no greater than 0.1 MPa.
  • the step of vacuum drying the dispersion to obtain copper particles with good dispersibility further comprises: controlling the drying temperature to be no more than 60°C.
  • ultrasonically dispersing the mixed liquid for at least 30 minutes and the step of obtaining the dispersion liquid specifically includes: placing the mixed liquid in an ultrasonic field and performing ultrasonic dispersion for at least 30 minutes to obtain the dispersion liquid.
  • the step of obtaining the copper particle solder paste specifically includes: adding the paste into the copper particles with good dispersibility according to the ratio of raw materials , and use mixing equipment to stir the copper particles and the paste until uniform, so as to obtain the copper particle solder paste.
  • the mixing equipment includes a planetary mixer.
  • the mixing speed of the mixing device is 2000 rpm.
  • the preparation method includes: dispersing copper particles to obtain copper particles with good dispersibility;
  • the following raw materials are prepared in parts by weight: copper particles with good dispersibility, a dispersant, a solvent and a reducing agent, wherein the weight part of the reducing agent is 0.5 to 5 parts;
  • Forming paste adding paste and dispersant to copper particles with good dispersibility according to the raw material ratio and stirring evenly to obtain copper particle solder paste.
  • the sintering method includes: preparing the following raw materials according to a preset weight: copper particles with good dispersibility, a dispersant , a solvent and a reducing agent, wherein the weight of the reducing agent is 0.5 to 5 parts; the reducing agent, the dispersing agent and the solvent are mixed according to the ratio of the raw materials and stirred evenly to obtain a paste; the paste is added according to the ratio of the raw materials.
  • the copper particles with good dispersibility are mixed evenly to obtain copper particle solder paste; pure nitrogen is pre-passed, and the copper particle solder paste is reflowed under nitrogen atmosphere to obtain a dense and continuous sintered layer.
  • the step of pre-passing pure nitrogen gas and reflow soldering the copper particle solder paste in a nitrogen atmosphere to obtain a dense and continuous sintered layer includes: controlling the heating rate to be 1-20° C./min.
  • the step of pre-passing pure nitrogen and reflow soldering the copper particle solder paste in a nitrogen atmosphere to obtain a dense and continuous sintered layer further includes: controlling the sintering temperature to be 250-300°C.
  • the step of pre-passing pure nitrogen gas and reflow soldering the copper particle solder paste in a nitrogen atmosphere to obtain a dense and continuous sintered layer further includes: controlling the sintering time to be 30 minutes.
  • the step of pre-passing pure nitrogen and reflow soldering the copper particle solder paste in a nitrogen atmosphere to obtain a dense and continuous sintered layer further includes: controlling the applied pressure to be 0.3-1 MPa.
  • the present application provides a copper particle solder paste and a preparation method and a sintering method thereof.
  • a certain amount of reducing agent to the copper paste, not only the oxidation on the surface of the copper particles can be removed It can also prevent the copper particle solder paste from being oxidized again during storage and use; and because the added reducing agent and its oxidation products are easily thermally decomposed, they will not hinder the sintering process, so that the copper particle solder paste can be used at low temperatures.
  • Sintering is performed without reducing gas protection during sintering, which not only reduces the production cost, but also improves the application range of the copper particle solder paste.
  • the present application solves the problems of complex process and high preparation cost, so that the produced copper particle solder paste meets the application requirements of "low temperature sintering, high temperature service", and can replace nano silver sintered solder paste or sintered nano silver paste Suitable for electronic packaging and micro-connection fields.
  • FIG. 1 is a schematic flowchart of an embodiment of a method for preparing copper particle solder paste of the present application
  • Fig. 2 is a detailed flow chart of an embodiment of step S11 in Fig. 1;
  • FIG. 3 is a schematic flowchart of an embodiment of the sintering method of the copper particle solder paste of the present application
  • 4a and 4b are SEM images of copper particles at different stages in Example 1 of the present application.
  • Fig. 5a and Fig. 5b are schematic diagrams comparing the SEM images of the connection joints obtained after the copper particle solder paste is sintered in Example 1 and Comparative Example 1 of the present application;
  • FIG. 6a and FIG. 6b are schematic diagrams showing the comparison of SEM images of the connection joints obtained after the copper particle solder paste is sintered in Example 3 and Example 4 of the present application.
  • the third-generation wide-bandgap semiconductor materials are widely used in high-power electronic devices because of their stable performance at a high temperature of 500 °C.
  • High temperature resistant and stable packaging interconnect materials are one of the important factors driving the development of power devices.
  • Traditional tin-lead solder paste can withstand high temperature, but because lead will pollute the environment and cause serious harm to human health, it does not meet the development trend of energy saving, environmental protection and green manufacturing, and is rarely used in electronic equipment.
  • common lead-free solders can meet high temperature resistance requirements, they all have their own shortcomings, such as high cost of silver and gold-based solders, easy corrosion of tin-based solders, and greater brittleness of bismuth-based solders.
  • nano-metal solder paste is a new type of packaging material in recent years, which can meet the packaging requirements of "low temperature sintering, high temperature service”.
  • the small size effect of nano-metal materials can promote the diffusion of atoms on the surface of metal particles, enabling welding at a lower temperature, while the size effect of particles in the bulk formed after welding disappears, and the remelting temperature returns to The melting point of the bulk metal ensures the high-temperature reliability of the nano-metal solder paste, so that it can meet the needs of the rapidly developing electronics industry.
  • Elemental copper has excellent thermal conductivity and electrical conductivity, and is cheap, easy to prepare into micro-nano copper particles, and is an ideal low-temperature sintering filler.
  • the copper particle solder paste currently produced due to the intrinsic oxidizing property of the copper particles, will be oxidized to varying degrees during the preparation and storage process, and the oxides formed on the surface of the copper particles will not only lead to the sintering of the copper particle solder paste Incomplete, it will significantly increase the interconnection temperature, reduce the sintering performance and connection strength; and in order to avoid further oxidation of the copper particle solder paste during the sintering process, it is necessary to add a reducing gas for protection, and sintering at high temperature and high pressure.
  • These auxiliary The method not only complicates the manufacturing process, but also greatly increases the manufacturing cost, which is not conducive to industrialized production.
  • the existing methods to prevent the oxidation of copper particle solder paste for example, use organic acid to corrode the surface of copper particles, and there is a certain probability to remove the oxide layer on the copper surface.
  • the treated copper particles have good sintering performance as fillers, but due to The surface of the corroded copper particles is unstable and is still easily re-oxidized, so this method will greatly reduce the storage time of the copper particle solder paste and limit its use range.
  • the present application provides a copper particle solder paste and a preparation method and a sintering method thereof.
  • a reducing agent added to the copper particle solder paste, the copper particle solder paste is prevented from being oxidized during storage and use.
  • the copper particle solder paste provided by the present application includes copper particles with good dispersibility, a dispersant and a solvent, and also includes a reducing agent, wherein the weight part of the reducing agent is 0.5-5 parts.
  • the produced copper particle solder paste can meet the application requirements of "low temperature sintering, high temperature service", and can replace nano silver sintering solder paste or sintered nano silver paste, which is suitable for electronic packaging and micro-connection fields.
  • the copper particle solder paste provided by the present application includes copper particles with good dispersibility, a dispersant and a solvent, and also includes a reducing agent, wherein the weight part of the reducing agent is 0.5-5 parts.
  • the copper particle solder paste includes the following raw materials in parts by weight: copper particles with good dispersibility, 75-90 parts; dispersant, 1-5 parts; solvent, 10-15 parts; reducing agent, 0.5 parts ⁇ 5 servings.
  • the total number of the above components is 100 parts.
  • the reducing agent includes at least one of ascorbic acid, copper formate, formic acid, acetic acid, and acetone oxime.
  • the reducing agents used in this application are all low-toxicity reagents, and both the reducing agent itself and its oxidation products are easily thermally decomposed.
  • Ascorbic acid also known as vitamin C, is an acidic polyhydroxy compound containing 6 carbon atoms. It has strong reducibility and is easily oxidized to dehydroascorbic acid, and ascorbic acid and its oxidation products are more than 80. It can be decomposed under the temperature environment of °C.
  • the particle diameter of the copper particles is 100 to 300 nm, and the copper particles are spherical.
  • the dispersing agent includes any one of polyvinylpyrrolidone K30, polyvinylpyrrolidone K90 and polyethylene glycol 1000.
  • the solvent includes at least one of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol 200, 2-amino-2-methyl-propanol and 1-amino-2-propanol A sort of.
  • the copper particle solder paste in this embodiment includes a certain amount of reducing agent, which can not only remove the oxide layer on the surface of the copper particle, but also prevent the copper particle solder paste from being oxidized again during storage and use. It has a shelf life equivalent to that of ordinary lead-free solder, and can be refrigerated after opening to ensure its sintering performance within a certain period of time (for example, 24 hours).
  • the present application provides a preparation method of copper particle solder paste.
  • FIG. 1 is a schematic flowchart of an embodiment of a method for preparing a copper particle solder paste of the present application. As shown in Figure 1, in this embodiment, the method includes:
  • S11 Disperse copper particles to obtain copper particles with good dispersibility.
  • the particle diameter of the copper particles is 100 to 300 nm, and the copper particles are spherical.
  • nano-copper particles can promote the diffusion of atoms on the surface of copper metal particles, enabling welding at lower temperatures, but due to the extremely high activity of metal nano-copper particles, and the In the presence of various adsorption forces, it is easy to form agglomerates between nanoparticles. Therefore, it is necessary to disperse copper particles to obtain copper particles with good dispersibility to achieve more prominent physical properties.
  • the following raw materials are prepared in parts by weight: copper particles with good dispersibility, 75-90 parts; dispersant, 1-5 parts; solvent, 10-15 parts; reducing agent, 0.5-5 parts.
  • the total number of the above components is 100 parts.
  • the reducing agent includes at least one of ascorbic acid, copper formate, formic acid, acetic acid, and acetone oxime.
  • the dispersing agent includes any one of polyvinylpyrrolidone K30, polyvinylpyrrolidone K90 and polyethylene glycol 1000.
  • the solvent includes at least one of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol 200, 2-amino-2-methyl-propanol and 1-amino-2-propanol A sort of.
  • the reducing agent and the solvent can be selected according to different materials of gold on the substrate and gold on the chip (eg, gold, silver, nickel, etc.).
  • the dispersing agent is polyvinylpyrrolidone K90 or polyethylene glycol 1000
  • the reducing agent, the dispersing agent and the solvent are mixed according to the ratio of raw materials and stirred uniformly to obtain a paste.
  • the dispersant is polyvinylpyrrolidone K30
  • the reducing agent and the solvent are mixed according to the raw material ratio and stirred uniformly to obtain a paste, which is not limited in this application.
  • the dispersant is polyvinylpyrrolidone K90 or polyethylene glycol 1000
  • the paste containing polyvinylpyrrolidone K90 or polyethylene glycol 1000 is added to the copper particles with good dispersibility according to the ratio of raw materials And stir evenly to obtain copper particle solder paste.
  • the paste and dispersant are added to copper particles with good dispersibility according to the raw material ratio and stirred evenly to obtain copper particle solder paste.
  • a mixing device is used to stir the copper particles and the paste to obtain a copper particle solder paste.
  • the mixing equipment includes a planetary mixer.
  • the mixing speed was 2000 rpm.
  • the planetary mixer refers to a device that uniformly mixes materials through the relative countercurrent motion among the suspension wheel, the planetary shovel and the side scraper in the grinding disc.
  • the device has low energy consumption, good sealing performance and is easy to use. Its working principle is that the motor drives the suspension wheel, the planetary shovel and the side scraper to revolve clockwise in the grinding disc through the pulley, the reduction box and the planetary gear box. The shovel rotates counterclockwise at the same time, so that the material can be fully stirred and kneaded in the grinding disc, so as to achieve the purpose of mixing and kneading.
  • the obtained copper particle solder paste can be used for coating, chip mounting and sintering, and by controlling the viscosity, connection layers with different thicknesses can be obtained, for example, the viscosity of the solder paste is controlled to be low, so that the thickness of the connection layer can be reduced low to meet different connection requirements.
  • adding a reducing agent to the copper particle solder paste can not only remove the oxide layer on the surface of the copper particle, but also prevent the copper particle solder paste from being oxidized again during storage and use; further , Because the preparation process is simple, and the added reducing agents are all low-toxicity reagents, the purpose of cost saving and stable production can also be achieved.
  • FIG. 2 is a detailed flowchart of an implementation manner of step S11 in FIG. 1 .
  • the method includes:
  • the following raw materials in parts by weight are prepared: copper particles, 1 part; absolute ethanol, 50 parts; dispersant, 0.5 part.
  • the dispersing agent includes any one of polyvinylpyrrolidone K30, polyvinylpyrrolidone K90 and polyethylene glycol 1000.
  • the mixed liquid is placed in an ultrasonic field, and the nanoparticle suspension is treated with ultrasonic waves of appropriate frequency and power.
  • the mechanism of ultrasonic dispersion is related to cavitation, which can generate high temperature and high pressure locally on the copper particles, and is accompanied by a micro-jet with a huge impact force, thereby producing a micro-pulverization effect on the copper particles and breaking the agglomerates. Thereby, copper particles with more uniform dispersion are obtained.
  • the degree of vacuum is controlled to be no greater than 0.1 MPa, and the drying temperature is controlled to be no greater than 60°C.
  • the present application can obtain copper particles with more uniform and better monodispersity, so as to achieve more outstanding physical properties. Soldering at low temperature to meet the packaging requirements of "low temperature sintering".
  • FIG. 3 is a schematic flowchart of an embodiment of a method for sintering copper particle solder paste of the present application. As shown in Figure 3, in this embodiment, the method includes:
  • the following raw materials are prepared in parts by weight: copper particles with good dispersibility, 75-90 parts; dispersant, 1-5 parts; solvent, 10-15 parts; reducing agent, 0.5-5 parts.
  • the total number of the above components is 100 parts.
  • the reducing agent includes at least one of ascorbic acid, copper formate, formic acid, acetic acid, and acetone oxime.
  • the dispersing agent includes any one of polyvinylpyrrolidone K30, polyvinylpyrrolidone K90 and polyethylene glycol 1000.
  • the solvent includes at least one of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol 200, 2-amino-2-methyl-propanol and 1-amino-2-propanol A sort of.
  • the dispersing agent is polyvinylpyrrolidone K90 or polyethylene glycol 1000
  • the reducing agent, the dispersing agent and the solvent are mixed according to the raw material ratio and stirred to obtain a paste.
  • the dispersant is polyvinylpyrrolidone K30
  • the reducing agent and the solvent are mixed according to the raw material ratio and stirred uniformly to obtain a paste, which is not limited in this application.
  • the dispersant is polyvinylpyrrolidone K90 or polyethylene glycol 1000
  • the paste containing polyvinylpyrrolidone K90 or polyethylene glycol 1000 is added to the copper particles with good dispersibility according to the ratio of raw materials And stir evenly to obtain copper particle solder paste.
  • the paste and dispersant are added to copper particles with good dispersibility according to the raw material ratio and stirred evenly to obtain copper particle solder paste.
  • the heating rate is controlled to be 1-20° C./min
  • the sintering temperature is controlled to be 250-300° C.
  • the sintering time is controlled to be 30 minutes.
  • the applied pressure is controlled to be 0.3-1 MPa.
  • the obtained sintering strength is about 20MPa-35MPa, which is equivalent to the sintering strength of traditional tin-lead solder paste.
  • Reflow refers to remelting the paste solder pre-distributed to the printed board pads to achieve mechanical and Soldering of electrical connections.
  • Reflow soldering relies on the circulating flow of gas in the welding machine to generate high temperature, thereby acting on the solder joints, so that the gelatinous flux undergoes a physical reaction under a certain high temperature airflow to achieve the welding of Surface Mounted Devices (SMD).
  • SMD Surface Mounted Devices
  • the copper particle solder paste since the copper particle solder paste includes a reducing agent, it can not only remove the oxide layer on the surface of the copper particle, but also prevent the copper particle solder paste from being oxidized again during storage and use. There is no need to add reducing gases such as hydrogen or formic acid for protection during the sintering process; and since there is no oxide layer on the surface of the copper particles that hinders the sintering process, it is not necessary to sinter under high temperature and high pressure.
  • reducing gases such as hydrogen or formic acid for protection during the sintering process
  • the copper Application range of particle solder paste By reducing the requirements for the sintering environment, the copper Application range of particle solder paste; further, the sintering strength obtained by the copper particle solder paste in this application after sintering is equivalent to that of traditional tin-lead solder paste, which meets the packaging requirements of "low temperature sintering, high temperature service", and can replace nano-silver sintering Solder paste or sintered nano-silver paste is suitable for electronic packaging and micro-connection fields.
  • SEM Scanning electron microscope
  • FIG. 4a and FIG. 4b are SEM images of copper particles at different stages in Example 1 of the present application; wherein, FIG. Figure 4b is the SEM image of the connection joint obtained after the copper particle solder paste is sintered in Example 1 of the present application.
  • the small size effect of nano-copper particles can promote the diffusion of atoms on the surface of copper metal particles, enabling it to be welded at a lower temperature to meet the requirements of "low temperature sintering"; adding reduction After sintering, the copper particle solder paste is sintered at a lower temperature.
  • the joint structure formed after sintering is dense, the particle size effect disappears, and the remelting temperature returns to the melting point of the bulk metal, ensuring the high temperature of the copper particle solder paste. Reliability, to meet the packaging requirements of "high temperature service”.
  • the following raw materials by weight were prepared: copper particles with good dispersibility, 85 parts, wherein the copper particles had a particle size of 300 nm; polyvinylpyrrolidone K90, 1 part; ethylene glycol, 14 parts; Diols are mixed according to the ratio of raw materials and stirred evenly to obtain a paste; the paste is added to the copper particles with good dispersibility according to the ratio of raw materials and stirred evenly to obtain a copper particle solder paste; the copper particle solder paste is used for For chip bonding of copper-backed silicon wafer and copper substrate, pure nitrogen is pre-passed, and the copper particle solder paste is reflowed under nitrogen atmosphere, and the pressure is increased to 0.4MPa, and the temperature is controlled to 300 °C to obtain the connection strength (shear stress) 8MPa connection joint.
  • FIG. 5a and FIG. 5b are schematic diagrams showing the comparison of the SEM images of the connection joints obtained after the copper particle solder paste is sintered in Example 1 and Comparative Example 1 of the present application; wherein, FIG. 5a is a The SEM image of the connection joint obtained after the copper particle solder paste is sintered in Example 1 of the present application, and FIG. 5b is the SEM image of the connection joint obtained after the copper particle solder paste is sintered in Comparative Example 1 of the present application.
  • Copper particles with good dispersibility 80 parts, wherein the copper particles have a particle size of 100 nm; polyethylene glycol 1000, 1 part; triethanolamine, 14 parts; formic acid, 5 parts; , polyethylene glycol 1000 and triethanolamine are mixed according to the ratio of raw materials and stirred evenly to obtain a paste; the paste is added to the copper particles with good dispersibility according to the ratio of raw materials and stirred evenly to obtain copper particle solder paste;
  • SEM Scanning electron microscope
  • Copper particles with good dispersibility 82 parts, wherein the particle size of the copper particles is 300 nm; polyethylene glycol 1000, 1 part; triethylene glycol, 15 parts; ascorbic acid, 2 parts; Mix ascorbic acid, polyethylene glycol 1000 and triethylene glycol according to the ratio of raw materials and stir evenly to obtain a paste; add the paste into copper particles with good dispersibility according to the ratio of raw materials and stir evenly to obtain copper Particle solder paste; copper particle solder paste is used for the connection between silicon carbide (SiC) chips and ceramic copper clad laminates (Direct Bonding Copper, DBC), and pure nitrogen is pre-passed, and the copper particle solder paste is reflowed under nitrogen atmosphere. , the pressure is 0.7MPa, and the temperature is controlled at 300°C to obtain a connection joint with a connection strength (shear stress) of 34MPa.
  • SiC silicon carbide
  • DBC Direct Bonding Copper
  • Copper particles with good dispersibility 82 parts, wherein the particle size of the copper particles is 300 nm; polyethylene glycol 1000, 1 part; triethylene glycol, 15 parts; ascorbic acid, 2 parts; Mix ascorbic acid, polyethylene glycol 1000 and triethylene glycol according to the ratio of raw materials and stir evenly to obtain a paste; add the paste into copper particles with good dispersibility according to the ratio of raw materials and stir evenly to obtain copper Particle solder paste; copper particle solder paste is used for the connection between silicon carbide (SiC) chips and ceramic copper clad laminates (Direct Bonding Copper, DBC), and the copper particle solder paste is reflowed under formic acid atmosphere, and the low pressure is 0.7MPa , control the temperature to 300 °C, and obtain the connection joint with the connection strength (shear stress) of 30MPa.
  • SiC silicon carbide
  • DBC Direct Bonding Copper
  • Example 3 and Example 4 scanning electron microscopy (SEM) was used to observe the microscopic features of the connection joints obtained after sintering the copper particle solder paste in Example 3 and Example 4, respectively.
  • FIG. 6a and FIG. 6b are schematic diagrams showing the comparison of the SEM images of the connection joints obtained after the copper particle solder paste is sintered in Example 3 and Example 4 of the present application; wherein, FIG. 6a is a The SEM image of the connection joint obtained after the copper particle solder paste is sintered in Example 3 of the present application, and FIG. 6b is the SEM image of the connection joint obtained after the copper particle solder paste is sintered in Example 4 of the present application.
  • connection joints formed after the copper particle solder pastes in Example 3 and Example 4 are sintered have dense structures, indicating that after adding a reducing agent to the copper particle solder paste, the solder paste During sintering, a connection structure with comparable strength can be formed without reducing gas protection.

Abstract

A copper particle solder paste, and a preparation method and a sintering method therefor. The copper particle solder paste comprises copper particles having good dispersion, a dispersant, and a solvent, and further comprises a reductant, wherein the amount of the reductant is 0.5-5 parts by weight. The reductant includes at least one of ascorbic acid, copper formate, formic acid, acetic acid, and acetone oxime. By adding the reductant to the copper particle solder paste, not only the oxide layer on the surface of the copper particles can be removed, but also the copper particle solder paste can be prevented from being oxidized again during storage and use; in addition, since the added reductant and an oxidation product thereof are prone to be thermally decomposed, and do not hinder the sintering process, the copper particle solder paste can be sintered at a low temperature without reducing gas protection during sintering, thereby not only reducing production costs, but also widening the application range of the copper particle solder paste.

Description

一种铜颗粒焊膏及其制备方法以及烧结方法A kind of copper particle solder paste and its preparation method and sintering method 【技术领域】【Technical field】
本申请涉及电子制造技术领域，特别是涉及一种铜颗粒焊膏及其制备方法以及烧结方法。The present application relates to the technical field of electronic manufacturing, and in particular, to a copper particle solder paste, a preparation method thereof, and a sintering method.
【背景技术】【Background technique】
微电子技术的革新引领了目前电子科技的发展，伴随着电子技术的快速更新换代，微电子封装技术受到的重视日益增加。目前，第三代固态功率半导体器件的出现有望在减少输电损耗的同时，极大地提高电能的利用率，并且在同样的面积内能调控更大电力，有助于器件的小型化发展。但是，高集成度所带来的发热问题制约了第三代半导体的应用。由于热膨胀系数的不匹配，基板与芯片之间的连接层在器件工作时，不断承受着热应力循环，而传统的锡(Sn)基焊料由于熔点较低，在此种循环应力下经常发生热裂、剥离等失效情况。The innovation of microelectronics technology leads the development of current electronic technology. With the rapid upgrading of electronic technology, the attention of microelectronics packaging technology is increasing day by day. At present, the emergence of third-generation solid-state power semiconductor devices is expected to greatly improve the utilization rate of electric energy while reducing power transmission losses, and can control more power in the same area, which is conducive to the miniaturization of devices. However, the heating problem brought about by high integration restricts the application of third-generation semiconductors. Due to the mismatch of thermal expansion coefficients, the connection layer between the substrate and the chip is constantly subjected to thermal stress cycles during the operation of the device, while traditional tin (Sn)-based solders often generate heat under such cyclic stress due to their low melting point. Cracking, peeling and other failures.
随着纳米技术的不断发展，纳米金属焊膏是近年来新兴的一类封装材料，能够实现“低温烧结，高温服役”的封装需求。具体地，纳米金属材料的小尺寸效应可促进金属颗粒表面原子的扩散，使其能够在较低的温度下进行焊接，而焊接后形成的块体中颗粒的尺度效应消失，重熔温度恢复到块体金属的熔点，从而保证了纳米金属焊膏的高温可靠性，使其能够满足目前快速发展的电子工业需要。With the continuous development of nanotechnology, nano-metal solder paste is a new type of packaging material in recent years, which can meet the packaging requirements of "low temperature sintering, high temperature service". Specifically, the small size effect of nano-metal materials can promote the diffusion of atoms on the surface of metal particles, enabling welding at a lower temperature, while the size effect of particles in the bulk formed after welding disappears, and the remelting temperature returns to The melting point of the bulk metal ensures the high-temperature reliability of the nano-metal solder paste, so that it can meet the needs of the rapidly developing electronics industry.
铜单质具有优良的热导率和电导率，且价格便宜，易制备为微纳米铜颗粒，是理想的低温烧结填料。然而，现有技术中的铜颗粒焊膏在较低的焊接温度下(<300℃)难以获得可靠的烧结结构，主要是由于铜的化学性质活泼，在空气中极易氧化，且生产的氧化铜层不易热分解，不仅阻碍了铜原子的扩散，还会增加烧结温度，加大了铜颗粒低温烧结的难度。Elemental copper has excellent thermal conductivity and electrical conductivity, and is cheap, easy to prepare into micro-nano copper particles, and is an ideal low-temperature sintering filler. However, it is difficult for the copper particle solder paste in the prior art to obtain a reliable sintered structure at a relatively low soldering temperature (<300°C), mainly due to the active chemical properties of copper, which is easily oxidized in the air, and the production of oxidized The copper layer is not easy to be thermally decomposed, which not only hinders the diffusion of copper atoms, but also increases the sintering temperature, which increases the difficulty of low-temperature sintering of copper particles.
【发明内容】[Content of the invention]
本申请主要解决的技术问题是提供一种铜颗粒焊膏及其制备方法以及烧结方法，通过在铜颗粒焊膏中加入还原剂，避免铜颗粒焊膏在存放以及使用过程中被氧化。The main technical problem to be solved by the present application is to provide a copper particle solder paste, a preparation method and a sintering method thereof. By adding a reducing agent to the copper particle solder paste, the copper particle solder paste is prevented from being oxidized during storage and use.
为解决上述技术问题，本申请采用的一个技术方案是提供一种铜颗粒焊膏， 该焊膏包括具有良好分散性的铜颗粒、分散剂以及溶剂，还包括还原剂，其中，还原剂的重量份为0.5～5份。In order to solve the above technical problems, a technical solution adopted in the present application is to provide a copper particle solder paste, the solder paste includes copper particles with good dispersibility, a dispersant and a solvent, and also includes a reducing agent, wherein the weight of the reducing agent is The serving is 0.5 to 5 servings.
其中，还原剂包括抗坏血酸、甲酸铜、甲酸、乙酸以及丙酮肟中的至少一种。Wherein, the reducing agent includes at least one of ascorbic acid, copper formate, formic acid, acetic acid and acetone oxime.
其中，铜颗粒的粒径为100～300nm。Among them, the particle diameter of the copper particles is 100 to 300 nm.
其中，铜颗粒为球型。Among them, the copper particles are spherical.
其中，分散剂包括聚乙烯吡咯烷酮K30、聚乙烯吡咯烷酮K90以及聚乙二醇1000中的任一种。Wherein, the dispersing agent includes any one of polyvinylpyrrolidone K30, polyvinylpyrrolidone K90 and polyethylene glycol 1000.
其中，溶剂包括乙二醇、二乙二醇、三乙二醇、聚乙二醇200、2-氨基-2-甲基-丙醇以及1-氨基-2-丙醇中的至少一种。Wherein, the solvent includes at least one of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol 200, 2-amino-2-methyl-propanol and 1-amino-2-propanol.
为解决上述技术问题，本申请采用的又一个技术方案是提供一种铜颗粒焊膏的制备方法，该制备方法包括：对铜颗粒进行分散处理，获得具有良好分散性的铜颗粒；按预设重量份准备以下原料：具有良好分散性的铜颗粒、分散剂、溶剂以及还原剂，其中，还原剂的重量份为0.5～5份；将还原剂、分散剂以及溶剂按原料配比混合并搅拌均匀，获得成膏体；将成膏体加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏。In order to solve the above technical problems, another technical solution adopted in the present application is to provide a preparation method of copper particle solder paste, the preparation method includes: dispersing copper particles to obtain copper particles with good dispersibility; Prepare the following raw materials in parts by weight: copper particles with good dispersibility, a dispersant, a solvent and a reducing agent, wherein the weight part of the reducing agent is 0.5 to 5 parts; the reducing agent, the dispersing agent and the solvent are mixed and stirred according to the ratio of the raw materials Evenly, a paste is obtained; the paste is added to the copper particles with good dispersibility according to the raw material ratio and stirred evenly to obtain a copper particle solder paste.
其中，对铜颗粒进行分散处理，获得具有良好分散性的铜颗粒的步骤具体包括：按预设重量份准备以下原料：铜颗粒、无水乙醇，以及分散剂；将铜颗粒以及分散剂按原料配比加入按原料配比的无水乙醇中，获得混合液体；将混合液体超声分散至少30分钟，获得分散液；对分散液进行真空干燥，获得具有良好分散性的铜颗粒。Wherein, the step of dispersing the copper particles to obtain copper particles with good dispersibility specifically includes: preparing the following raw materials according to a preset weight: copper particles, anhydrous ethanol, and a dispersant; The mixture is added into anhydrous ethanol according to the ratio of the raw materials to obtain a mixed liquid; the mixed liquid is ultrasonically dispersed for at least 30 minutes to obtain a dispersion; the dispersion is vacuum-dried to obtain copper particles with good dispersibility.
其中，对分散液进行真空干燥，获得具有良好分散性的铜颗粒的步骤还包括：控制真空度不大于0.1MPa。Wherein, the step of vacuum-drying the dispersion to obtain copper particles with good dispersibility further includes: controlling the degree of vacuum to be no greater than 0.1 MPa.
其中，对分散液进行真空干燥，获得具有良好分散性的铜颗粒的步骤进一步包括：控制干燥温度不大于60℃。Wherein, the step of vacuum drying the dispersion to obtain copper particles with good dispersibility further comprises: controlling the drying temperature to be no more than 60°C.
其中，将混合液体超声分散至少30分钟，获得分散液的步骤具体包括：将混合液体置于超声场中，进行超声分散至少30分钟，以获得分散液。Wherein, ultrasonically dispersing the mixed liquid for at least 30 minutes, and the step of obtaining the dispersion liquid specifically includes: placing the mixed liquid in an ultrasonic field and performing ultrasonic dispersion for at least 30 minutes to obtain the dispersion liquid.
其中，将成膏体加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏的步骤具体包括：将成膏体加入按原料配比的具有良好分散性的铜颗粒中，使用混合设备对铜颗粒以及成膏体进行搅拌至均匀，以获得铜颗粒焊膏。Wherein, adding the paste into the copper particles with good dispersibility according to the ratio of raw materials and stirring them evenly, the step of obtaining the copper particle solder paste specifically includes: adding the paste into the copper particles with good dispersibility according to the ratio of raw materials , and use mixing equipment to stir the copper particles and the paste until uniform, so as to obtain the copper particle solder paste.
其中，混合设备包括行星式混料机。Among them, the mixing equipment includes a planetary mixer.
其中，混合设备的混合速度为2000rpm。Wherein, the mixing speed of the mixing device is 2000 rpm.
为解决上述技术问题，本申请采用的另一个技术方案是提供一种铜颗粒焊膏的制备方法，该制备方法包括：对铜颗粒进行分散处理，获得具有良好分散性的铜颗粒；按预设重量份准备以下原料：具有良好分散性的铜颗粒、分散剂、溶剂以及还原剂，其中，还原剂的重量份为0.5～5份；将还原剂以及溶剂按原料配比混合并搅拌均匀，获得成膏体；将成膏体以及分散剂加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏。In order to solve the above technical problem, another technical solution adopted in the present application is to provide a preparation method of copper particle solder paste, the preparation method includes: dispersing copper particles to obtain copper particles with good dispersibility; The following raw materials are prepared in parts by weight: copper particles with good dispersibility, a dispersant, a solvent and a reducing agent, wherein the weight part of the reducing agent is 0.5 to 5 parts; Forming paste; adding paste and dispersant to copper particles with good dispersibility according to the raw material ratio and stirring evenly to obtain copper particle solder paste.
为解决上述技术问题，本申请采用的又一个技术方案是提供一种铜颗粒焊膏的烧结方法，该烧结方法包括：按预设重量份准备以下原料：具有良好分散性的铜颗粒、分散剂、溶剂以及还原剂，其中，还原剂的重量份为0.5～5份；将还原剂、分散剂以及溶剂按原料配比混合并搅拌均匀，获得成膏体；将成膏体加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏；预通纯氮气，在氮气气氛下对铜颗粒焊膏进行回流焊，以获得致密连续的烧结层。In order to solve the above technical problem, another technical solution adopted in the present application is to provide a sintering method for copper particle solder paste, the sintering method includes: preparing the following raw materials according to a preset weight: copper particles with good dispersibility, a dispersant , a solvent and a reducing agent, wherein the weight of the reducing agent is 0.5 to 5 parts; the reducing agent, the dispersing agent and the solvent are mixed according to the ratio of the raw materials and stirred evenly to obtain a paste; the paste is added according to the ratio of the raw materials. The copper particles with good dispersibility are mixed evenly to obtain copper particle solder paste; pure nitrogen is pre-passed, and the copper particle solder paste is reflowed under nitrogen atmosphere to obtain a dense and continuous sintered layer.
其中，预通纯氮气，在氮气气氛下对铜颗粒焊膏进行回流焊，以获得致密连续的烧结层的步骤包括：控制升温速率为1～20℃/min。The step of pre-passing pure nitrogen gas and reflow soldering the copper particle solder paste in a nitrogen atmosphere to obtain a dense and continuous sintered layer includes: controlling the heating rate to be 1-20° C./min.
其中，预通纯氮气，在氮气气氛下对铜颗粒焊膏进行回流焊，以获得致密连续的烧结层的步骤还包括：控制烧结温度为250～300℃。The step of pre-passing pure nitrogen and reflow soldering the copper particle solder paste in a nitrogen atmosphere to obtain a dense and continuous sintered layer further includes: controlling the sintering temperature to be 250-300°C.
其中，预通纯氮气，在氮气气氛下对铜颗粒焊膏进行回流焊，以获得致密连续的烧结层的步骤进一步包括：控制烧结时间为30min。The step of pre-passing pure nitrogen gas and reflow soldering the copper particle solder paste in a nitrogen atmosphere to obtain a dense and continuous sintered layer further includes: controlling the sintering time to be 30 minutes.
其中，预通纯氮气，在氮气气氛下对铜颗粒焊膏进行回流焊，以获得致密连续的烧结层的步骤还包括：控制施加的压力为0.3～1MPa。The step of pre-passing pure nitrogen and reflow soldering the copper particle solder paste in a nitrogen atmosphere to obtain a dense and continuous sintered layer further includes: controlling the applied pressure to be 0.3-1 MPa.
本申请的有益效果是：区别于现有技术，本申请提供一种铜颗粒焊膏及其制备方法以及烧结方法，通过在铜膏中添加一定量的还原剂，不仅能够去除铜颗粒表面的氧化层，还能够避免铜颗粒焊膏在保存以及使用过程中再次被氧化；且由于加入的还原剂及其氧化产物均易热分解，不会阻碍烧结过程，从而使铜颗粒焊膏能够在低温下进行烧结，且烧结时无需还原性气体保护，不仅降低了生产成本，还提升了铜颗粒焊膏的应用范围。通过上述方式，本申请解决了工艺复杂、制备成本高的问题，使生产出的铜颗粒焊膏满足“低温烧结，高温服役”的应用需求，能够替代纳米银烧结焊膏或烧结型纳米银浆适用于电子封装 和微连接领域。The beneficial effects of the present application are: different from the prior art, the present application provides a copper particle solder paste and a preparation method and a sintering method thereof. By adding a certain amount of reducing agent to the copper paste, not only the oxidation on the surface of the copper particles can be removed It can also prevent the copper particle solder paste from being oxidized again during storage and use; and because the added reducing agent and its oxidation products are easily thermally decomposed, they will not hinder the sintering process, so that the copper particle solder paste can be used at low temperatures. Sintering is performed without reducing gas protection during sintering, which not only reduces the production cost, but also improves the application range of the copper particle solder paste. Through the above method, the present application solves the problems of complex process and high preparation cost, so that the produced copper particle solder paste meets the application requirements of "low temperature sintering, high temperature service", and can replace nano silver sintered solder paste or sintered nano silver paste Suitable for electronic packaging and micro-connection fields.
【附图说明】【Description of drawings】
为了更清楚地说明本申请实施例中的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本申请的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他的附图。In order to illustrate the technical solutions in the embodiments of the present application more clearly, the following briefly introduces the drawings that are used in the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without creative effort.
图1是本申请铜颗粒焊膏的制备方法一实施方式的流程示意图；1 is a schematic flowchart of an embodiment of a method for preparing copper particle solder paste of the present application;
图2是图1中步骤S11一实施方式的细化流程图；Fig. 2 is a detailed flow chart of an embodiment of step S11 in Fig. 1;
图3是本申请铜颗粒焊膏的烧结方法一实施方式的流程示意图；FIG. 3 is a schematic flowchart of an embodiment of the sintering method of the copper particle solder paste of the present application;
图4a与图4b是本申请实施例1中铜颗粒在不同阶段的SEM图；4a and 4b are SEM images of copper particles at different stages in Example 1 of the present application;
图5a与图5b是本申请实施例1与对比例1中铜颗粒焊膏烧结后所获得的连接接头的SEM图的对比示意图；Fig. 5a and Fig. 5b are schematic diagrams comparing the SEM images of the connection joints obtained after the copper particle solder paste is sintered in Example 1 and Comparative Example 1 of the present application;
图6a与图6b是本申请实施例3与实施例4中铜颗粒焊膏烧结后所获得的连接接头的SEM图的对比示意图。6a and FIG. 6b are schematic diagrams showing the comparison of SEM images of the connection joints obtained after the copper particle solder paste is sintered in Example 3 and Example 4 of the present application.
【具体实施方式】【detailed description】
下面将结合本申请实施例中的附图，对本申请实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。基于本申请中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，均属于本申请保护的范围。The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, but not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of this application.
在本申请实施例中使用的术语是仅仅出于描述特定实施例的目的，而非旨在限制本申请。在本申请实施例和所附权利要求书中所使用的单数形式的“一种”、“所述”和“该”也旨在包括多数形式，除非上文清楚地表示其他含义，“多种”一般包含至少两种，但是不排除包含至少一种的情况。The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. As used in the examples of this application and the appended claims, the singular forms "a," "the," and "the" are intended to include the plural forms as well, unless the above clearly dictates otherwise, "a plurality of" "Generally includes at least two, but does not exclude the case of including at least one.
应当理解，本文中使用的术语“和/或”仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。It should be understood that the term "and/or" used in this document is only an association relationship to describe the associated objects, indicating that there may be three kinds of relationships, for example, A and/or B, which may indicate that A exists alone, and A and B exist at the same time. B, there are three cases of B alone. In addition, the character "/" in this document generally indicates that the related objects are an "or" relationship.
应当理解，本文中使用的术语“包括”、“包含”或者其他任何变体意在涵盖非排他性的包含，从而使得包括一系列要素的过程、方法、物品或者设备不 仅包括那些要素，而且还包括没有明确列出的其他要素，或者是还包括为这种过程、方法、物品或者设备所固有的要素。在没有更多限制的情况下，由语句“包括……”限定的要素，并不排除在包括所述要素的过程、方法、物品或者设备中还存在另外的相同要素。It should be understood that the terms "comprising", "comprising" or any other variation used herein are intended to encompass a non-exclusive inclusion such that a process, method, article or device comprising a series of elements includes not only those elements, but also Other elements not expressly listed or inherent to such a process, method, article or apparatus are also included. Without further limitation, an element defined by the phrase "comprises" does not preclude the presence of additional identical elements in a process, method, article, or device that includes the element.
随着电子器件逐渐向小型化、高密度、高集成方向发展，第三代宽带隙半导体材料因可以在500℃高温下具有稳定的性能而被广泛应用于高功率电子器件中，故找出合适的耐高温且稳定性高的封装互连材料，是推动功率器件发展的重要因素之一。传统锡铅焊膏可以耐受高温，但由于铅会污染环境，且会对人体健康造成严重危害，不符合节能环保和绿色制造的发展趋势，现已极少被使用在电子设备中。普通的无铅焊料虽然可以满足耐高温需求，但是均含有各自的缺点，例如，银、金基焊料成本较高、锡基焊料易被腐蚀、铋基焊料脆性较大等。With the gradual development of electronic devices towards miniaturization, high density and high integration, the third-generation wide-bandgap semiconductor materials are widely used in high-power electronic devices because of their stable performance at a high temperature of 500 °C. High temperature resistant and stable packaging interconnect materials are one of the important factors driving the development of power devices. Traditional tin-lead solder paste can withstand high temperature, but because lead will pollute the environment and cause serious harm to human health, it does not meet the development trend of energy saving, environmental protection and green manufacturing, and is rarely used in electronic equipment. Although common lead-free solders can meet high temperature resistance requirements, they all have their own shortcomings, such as high cost of silver and gold-based solders, easy corrosion of tin-based solders, and greater brittleness of bismuth-based solders.
随着纳米技术的不断发展，纳米金属焊膏是近年来新兴的一类封装材料，能够实现“低温烧结，高温服役”的封装需求。具体地，纳米金属材料的小尺寸效应可促进金属颗粒表面原子的扩散，使其能够在较低的温度下进行焊接，而焊接后形成的块体中颗粒的尺度效应消失，重熔温度恢复到块体金属的熔点，从而保证了纳米金属焊膏的高温可靠性，使其能够满足目前快速发展的电子工业需要。With the continuous development of nanotechnology, nano-metal solder paste is a new type of packaging material in recent years, which can meet the packaging requirements of "low temperature sintering, high temperature service". Specifically, the small size effect of nano-metal materials can promote the diffusion of atoms on the surface of metal particles, enabling welding at a lower temperature, while the size effect of particles in the bulk formed after welding disappears, and the remelting temperature returns to The melting point of the bulk metal ensures the high-temperature reliability of the nano-metal solder paste, so that it can meet the needs of the rapidly developing electronics industry.
铜单质具有优良的热导率和电导率，且价格便宜，易制备为微纳米铜颗粒，是理想的低温烧结填料。目前生产出来的铜颗粒焊膏，由于铜颗粒的本征氧化性，其在制备以及存放的过程中均会发生不同程度的氧化，而铜颗粒表面形成的氧化物不仅会导致铜颗粒焊膏烧结不完全，还会显著增加互连温度，降低烧结性能与连接强度；且为了避免铜颗粒焊膏在烧结过程中进一步氧化，还需要添加还原性气体进行保护，在高温高压下进行烧结，这些辅助手段不仅使制造工艺复杂化，还大幅提升了制备成本，不利于进行工业化生产。Elemental copper has excellent thermal conductivity and electrical conductivity, and is cheap, easy to prepare into micro-nano copper particles, and is an ideal low-temperature sintering filler. The copper particle solder paste currently produced, due to the intrinsic oxidizing property of the copper particles, will be oxidized to varying degrees during the preparation and storage process, and the oxides formed on the surface of the copper particles will not only lead to the sintering of the copper particle solder paste Incomplete, it will significantly increase the interconnection temperature, reduce the sintering performance and connection strength; and in order to avoid further oxidation of the copper particle solder paste during the sintering process, it is necessary to add a reducing gas for protection, and sintering at high temperature and high pressure. These auxiliary The method not only complicates the manufacturing process, but also greatly increases the manufacturing cost, which is not conducive to industrialized production.
现有的防止铜颗粒焊膏氧化的方法，例如，使用有机酸腐蚀铜颗粒表面，有一定几率将铜表面的氧化层去除，经处理后的铜颗粒作为填料具有较好的烧结性能，但由于被腐蚀后的铜颗粒表面不稳定，仍然容易被重新氧化，故这种方式会极大地降低铜颗粒焊膏的保存时间以及限制其使用范围。The existing methods to prevent the oxidation of copper particle solder paste, for example, use organic acid to corrode the surface of copper particles, and there is a certain probability to remove the oxide layer on the copper surface. The treated copper particles have good sintering performance as fillers, but due to The surface of the corroded copper particles is unstable and is still easily re-oxidized, so this method will greatly reduce the storage time of the copper particle solder paste and limit its use range.
基于上述情况，本申请提供一种铜颗粒焊膏及其制备方法以及烧结方法，通过在铜颗粒焊膏中加入还原剂，避免铜颗粒焊膏在存放以及使用过程中被氧 化。Based on the above situation, the present application provides a copper particle solder paste and a preparation method and a sintering method thereof. By adding a reducing agent to the copper particle solder paste, the copper particle solder paste is prevented from being oxidized during storage and use.
本申请所提供的铜颗粒焊膏包括具有良好分散性的铜颗粒、分散剂以及溶剂，还包括还原剂，其中，还原剂的重量份为0.5～5份。The copper particle solder paste provided by the present application includes copper particles with good dispersibility, a dispersant and a solvent, and also includes a reducing agent, wherein the weight part of the reducing agent is 0.5-5 parts.
本申请通过在铜颗粒焊膏中加入还原剂，不仅能够去除铜颗粒表面的氧化层，还能够避免铜颗粒焊膏在保存以及使用过程中再次被氧化；且由于加入的还原剂及其氧化产物均易热分解，不会阻碍烧结过程，从而使铜颗粒焊膏能够在低温下进行烧结，且烧结时无需还原性气体保护，不仅降低了生产成本，还提升了铜颗粒焊膏的应用范围，从而使生产出的铜颗粒焊膏满足“低温烧结，高温服役”的应用需求，能够替代纳米银烧结焊膏或烧结型纳米银浆适用于电子封装和微连接领域。In the present application, by adding a reducing agent to the copper particle solder paste, not only can the oxide layer on the surface of the copper particle be removed, but also the copper particle solder paste can be prevented from being oxidized again during storage and use; and due to the added reducing agent and its oxidation products All are easily thermally decomposed and will not hinder the sintering process, so that the copper particle solder paste can be sintered at low temperature, and no reducing gas protection is required during sintering, which not only reduces the production cost, but also improves the application range of the copper particle solder paste. Therefore, the produced copper particle solder paste can meet the application requirements of "low temperature sintering, high temperature service", and can replace nano silver sintering solder paste or sintered nano silver paste, which is suitable for electronic packaging and micro-connection fields.
下面结合附图和实施方式对本申请进行详细说明。The present application will be described in detail below with reference to the accompanying drawings and embodiments.
本申请所提供的铜颗粒焊膏包括具有良好分散性的铜颗粒、分散剂以及溶剂，还包括包括还原剂，其中，还原剂的重量份为0.5～5份。The copper particle solder paste provided by the present application includes copper particles with good dispersibility, a dispersant and a solvent, and also includes a reducing agent, wherein the weight part of the reducing agent is 0.5-5 parts.
本实施方式中，铜颗粒焊膏包括以下按重量份计的原料：具有良好分散性的铜颗粒，75～90份；分散剂，1～5份；溶剂，10～15份；还原剂，0.5～5份。In this embodiment, the copper particle solder paste includes the following raw materials in parts by weight: copper particles with good dispersibility, 75-90 parts; dispersant, 1-5 parts; solvent, 10-15 parts; reducing agent, 0.5 parts ~ 5 servings.
其中，以上各组份的总份数为100份。Wherein, the total number of the above components is 100 parts.
本实施方式中，还原剂包括抗坏血酸、甲酸铜、甲酸、乙酸以及丙酮肟中的至少一种。In this embodiment, the reducing agent includes at least one of ascorbic acid, copper formate, formic acid, acetic acid, and acetone oxime.
具体地，本申请所使用的还原剂均为低毒试剂，且无论是还原剂本身还是其氧化产物均易热分解。Specifically, the reducing agents used in this application are all low-toxicity reagents, and both the reducing agent itself and its oxidation products are easily thermally decomposed.
此处以抗坏血酸为例，抗坏血酸又称维生素C，是一种含有6个碳原子的酸性多羟基化合物，具有很强的还原性，容易被氧化成脱氢抗坏血酸，且抗坏血酸和其氧化产物在超过80℃的温度环境下就可分解。Take ascorbic acid as an example here. Ascorbic acid, also known as vitamin C, is an acidic polyhydroxy compound containing 6 carbon atoms. It has strong reducibility and is easily oxidized to dehydroascorbic acid, and ascorbic acid and its oxidation products are more than 80. It can be decomposed under the temperature environment of ℃.
本实施方式中，铜颗粒的粒径为100～300nm，铜颗粒为球型。In this embodiment, the particle diameter of the copper particles is 100 to 300 nm, and the copper particles are spherical.
本实施方式中，分散剂包括聚乙烯吡咯烷酮K30、聚乙烯吡咯烷酮K90以及聚乙二醇1000中的任一种。In this embodiment, the dispersing agent includes any one of polyvinylpyrrolidone K30, polyvinylpyrrolidone K90 and polyethylene glycol 1000.
本实施方式中，溶剂包括乙二醇、二乙二醇、三乙二醇、聚乙二醇200、2-氨基-2-甲基-丙醇以及1-氨基-2-丙醇中的至少一种。In this embodiment, the solvent includes at least one of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol 200, 2-amino-2-methyl-propanol and 1-amino-2-propanol A sort of.
区别于现有技术，本实施方式中的铜颗粒焊膏中包括一定量的还原剂，不仅能够去除铜颗粒表面的氧化层，还能够避免铜颗粒焊膏在保存以及使用过程中再次被氧化，具有相当于普通无铅焊料的耐存性，在开封后进行冷藏，能够 在一定时间内(例如，24小时)保证其烧结性能。Different from the prior art, the copper particle solder paste in this embodiment includes a certain amount of reducing agent, which can not only remove the oxide layer on the surface of the copper particle, but also prevent the copper particle solder paste from being oxidized again during storage and use. It has a shelf life equivalent to that of ordinary lead-free solder, and can be refrigerated after opening to ensure its sintering performance within a certain period of time (for example, 24 hours).
对应地，本申请提供了一种铜颗粒焊膏的制备方法。Correspondingly, the present application provides a preparation method of copper particle solder paste.
请参阅图1，图1是本申请铜颗粒焊膏的制备方法一实施方式的流程示意图。如图1所示，在本实施方式中，该方法包括：Please refer to FIG. 1 , which is a schematic flowchart of an embodiment of a method for preparing a copper particle solder paste of the present application. As shown in Figure 1, in this embodiment, the method includes:
S11：对铜颗粒进行分散处理，获得具有良好分散性的铜颗粒。S11: Disperse copper particles to obtain copper particles with good dispersibility.
本实施方式中，铜颗粒的粒径为100～300nm，铜颗粒为球型。In this embodiment, the particle diameter of the copper particles is 100 to 300 nm, and the copper particles are spherical.
由于尺寸效应，当金属颗粒的尺寸降低到纳米级别时，其熔点随尺寸的减小而降低，这使得金属纳米颗粒能够实现“低温连接，高温服役”。Due to the size effect, when the size of metal particles is reduced to the nanometer level, their melting point decreases with the decrease in size, which enables metal nanoparticles to achieve "low temperature connection, high temperature service".
具体地，纳米铜颗粒由于具有小尺寸效应，能够促进铜金属颗粒表面原子的扩散，使其能够在较低的温度下进行焊接，但由于金属纳米铜颗粒具有极高的活性，以及纳米微粒间各种吸附力的存在，纳米颗粒间极易形成团聚体，因此，需要对铜颗粒进行分散处理，获得具有良好分散性的铜颗粒，以达到更加突出的物理性质。Specifically, due to the small size effect, nano-copper particles can promote the diffusion of atoms on the surface of copper metal particles, enabling welding at lower temperatures, but due to the extremely high activity of metal nano-copper particles, and the In the presence of various adsorption forces, it is easy to form agglomerates between nanoparticles. Therefore, it is necessary to disperse copper particles to obtain copper particles with good dispersibility to achieve more prominent physical properties.
S12：按预设重量份准备以下原料：具有良好分散性的铜颗粒、分散剂、溶剂以及还原剂，其中，还原剂的重量份为0.5～5份。S12: Prepare the following raw materials in preset weight parts: copper particles with good dispersibility, a dispersant, a solvent and a reducing agent, wherein the weight part of the reducing agent is 0.5-5 parts.
本实施方式中，准备以下按重量份计的原料：具有良好分散性的铜颗粒，75～90份；分散剂，1～5份；溶剂，10～15份；还原剂，0.5～5份。In this embodiment, the following raw materials are prepared in parts by weight: copper particles with good dispersibility, 75-90 parts; dispersant, 1-5 parts; solvent, 10-15 parts; reducing agent, 0.5-5 parts.
其中，以上各组份的总份数为100份。Wherein, the total number of the above components is 100 parts.
本实施方式中，还原剂包括抗坏血酸、甲酸铜、甲酸、乙酸以及丙酮肟中的至少一种。In this embodiment, the reducing agent includes at least one of ascorbic acid, copper formate, formic acid, acetic acid, and acetone oxime.
本实施方式中，分散剂包括聚乙烯吡咯烷酮K30、聚乙烯吡咯烷酮K90以及聚乙二醇1000中的任一种。In this embodiment, the dispersing agent includes any one of polyvinylpyrrolidone K30, polyvinylpyrrolidone K90 and polyethylene glycol 1000.
本实施方式中，溶剂包括乙二醇、二乙二醇、三乙二醇、聚乙二醇200、2-氨基-2-甲基-丙醇以及1-氨基-2-丙醇中的至少一种。In this embodiment, the solvent includes at least one of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol 200, 2-amino-2-methyl-propanol and 1-amino-2-propanol A sort of.
本实施方式中，还原剂与溶剂可根据不同基板地金和芯片背金的材料(例如，金、银、镍等)进行选择。In this embodiment, the reducing agent and the solvent can be selected according to different materials of gold on the substrate and gold on the chip (eg, gold, silver, nickel, etc.).
S13：将还原剂、分散剂以及溶剂按原料配比混合并搅拌均匀，获得成膏体。S13: Mix the reducing agent, the dispersing agent and the solvent according to the ratio of the raw materials and stir evenly to obtain a paste.
本实施方式中，当分散剂为聚乙烯吡咯烷酮K90或聚乙二醇1000时，将还原剂、分散剂以及溶剂按原料配比混合并搅拌均匀，获得成膏体。In this embodiment, when the dispersing agent is polyvinylpyrrolidone K90 or polyethylene glycol 1000, the reducing agent, the dispersing agent and the solvent are mixed according to the ratio of raw materials and stirred uniformly to obtain a paste.
在其他实施方式中，当分散剂为聚乙烯吡咯烷酮K30时，将还原剂以及溶剂按原料配比混合并搅拌均匀，获得成膏体，本申请对此不作限定。In other embodiments, when the dispersant is polyvinylpyrrolidone K30, the reducing agent and the solvent are mixed according to the raw material ratio and stirred uniformly to obtain a paste, which is not limited in this application.
S14：将成膏体加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏。S14: adding the paste into the copper particles with good dispersibility according to the raw material ratio and stirring evenly to obtain a copper particle solder paste.
本实施方式中，当分散剂为聚乙烯吡咯烷酮K90或聚乙二醇1000时，将含有聚乙烯吡咯烷酮K90或聚乙二醇1000的成膏体加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏。In this embodiment, when the dispersant is polyvinylpyrrolidone K90 or polyethylene glycol 1000, the paste containing polyvinylpyrrolidone K90 or polyethylene glycol 1000 is added to the copper particles with good dispersibility according to the ratio of raw materials And stir evenly to obtain copper particle solder paste.
在其他实施方式中，当分散剂为聚乙烯吡咯烷酮K30时，将成膏体与分散剂加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏。In other embodiments, when the dispersant is polyvinylpyrrolidone K30, the paste and dispersant are added to copper particles with good dispersibility according to the raw material ratio and stirred evenly to obtain copper particle solder paste.
本实施方式中，使用混合设备对铜颗粒以及成膏体进行搅拌，以获得铜颗粒焊膏。In this embodiment, a mixing device is used to stir the copper particles and the paste to obtain a copper particle solder paste.
其中，混合设备包括行星式混料机。Among them, the mixing equipment includes a planetary mixer.
其中，混合速度为2000rpm。Here, the mixing speed was 2000 rpm.
具体地，行星式混料机是指在碾盘内通过悬挂轮、行星铲及侧刮板三者之间的相对逆流运动，使物料得到均匀混合的设备。该设备能耗小，密封性好，使用方便。其工作原理是由电动机通过皮带轮、减速箱、行星齿轮箱带动悬挂轮、行星铲及侧刮板在碾盘内作顺时针方向公转，侧刮板将混合料推向悬挂轮和行星铲下面，行星铲同时又作逆时针自转，这样连续翻转搅拌，使物料在碾盘内得到充分的搅拌和捏合，达到混合与混练的目的。Specifically, the planetary mixer refers to a device that uniformly mixes materials through the relative countercurrent motion among the suspension wheel, the planetary shovel and the side scraper in the grinding disc. The device has low energy consumption, good sealing performance and is easy to use. Its working principle is that the motor drives the suspension wheel, the planetary shovel and the side scraper to revolve clockwise in the grinding disc through the pulley, the reduction box and the planetary gear box. The shovel rotates counterclockwise at the same time, so that the material can be fully stirred and kneaded in the grinding disc, so as to achieve the purpose of mixing and kneading.
进一步地，所获得铜颗粒焊膏可用于涂布、芯片搭载以及烧结，且通过对粘度进行控制，能够获得不同厚度的连接层，例如，控制焊膏的粘度偏低，从而使连接层的厚度偏低，以符合不同的连接要求。Further, the obtained copper particle solder paste can be used for coating, chip mounting and sintering, and by controlling the viscosity, connection layers with different thicknesses can be obtained, for example, the viscosity of the solder paste is controlled to be low, so that the thickness of the connection layer can be reduced low to meet different connection requirements.
区别于现有技术，本实施方式中，在铜颗粒焊膏中加入还原剂，不仅能够去除铜颗粒表面的氧化层，还能够避免铜颗粒焊膏在保存以及使用过程中再次被氧化；进一步地，由于制备过程简单，且加入的还原剂均为低毒试剂，还能够实现节约成本稳定生产的目的。Different from the prior art, in this embodiment, adding a reducing agent to the copper particle solder paste can not only remove the oxide layer on the surface of the copper particle, but also prevent the copper particle solder paste from being oxidized again during storage and use; further , Because the preparation process is simple, and the added reducing agents are all low-toxicity reagents, the purpose of cost saving and stable production can also be achieved.
进一步请参阅图2，图2是图1中步骤S11一实施方式的细化流程图。如图2所示，在本实施方式中，该方法包括：Please refer to FIG. 2 , which is a detailed flowchart of an implementation manner of step S11 in FIG. 1 . As shown in Figure 2, in this embodiment, the method includes:
S21：按预设重量份准备以下原料：铜颗粒、无水乙醇，以及分散剂。S21: Prepare the following raw materials according to a preset weight: copper particles, absolute ethanol, and a dispersant.
本实施方式中，准备以下按重量份计的原料：铜颗粒，1份；无水乙醇，50份；分散剂，0.5份。In this embodiment, the following raw materials in parts by weight are prepared: copper particles, 1 part; absolute ethanol, 50 parts; dispersant, 0.5 part.
其中，分散剂包括聚乙烯吡咯烷酮K30、聚乙烯吡咯烷酮K90以及聚乙二醇1000中的任一种。Wherein, the dispersing agent includes any one of polyvinylpyrrolidone K30, polyvinylpyrrolidone K90 and polyethylene glycol 1000.
S22：将铜颗粒以及分散剂按原料配比加入按原料配比的无水乙醇中，获得混合液体。S22: adding the copper particles and the dispersant to the absolute ethanol according to the raw material ratio to obtain a mixed liquid.
本实施方式中，将1份铜颗粒加入到50份无水乙醇中，同时加入0.5份分散剂，获得混合液体。In this embodiment, 1 part of copper particles is added to 50 parts of absolute ethanol, and 0.5 part of dispersant is added simultaneously to obtain a mixed liquid.
S23：将混合液体超声分散至少30分钟，获得分散液。S23: ultrasonically disperse the mixed liquid for at least 30 minutes to obtain a dispersion liquid.
本实施方式中，将混合液体置于超声场中，用适当的频率和功率的超声波对纳米颗粒悬浮液进行处理。In this embodiment, the mixed liquid is placed in an ultrasonic field, and the nanoparticle suspension is treated with ultrasonic waves of appropriate frequency and power.
具体地，超声波分散作用的机理与空化作用有关，空化作用可以在铜颗粒局部产生高温高压，并且伴随巨大的冲击力的微射流，从而对铜颗粒产生微粉碎作用，使团聚体破碎，从而获得分散性更单一的铜颗粒。Specifically, the mechanism of ultrasonic dispersion is related to cavitation, which can generate high temperature and high pressure locally on the copper particles, and is accompanied by a micro-jet with a huge impact force, thereby producing a micro-pulverization effect on the copper particles and breaking the agglomerates. Thereby, copper particles with more uniform dispersion are obtained.
S24：对分散液进行真空干燥，获得具有良好分散性的铜颗粒。S24: Vacuum-dry the dispersion to obtain copper particles with good dispersibility.
本实施方式中，控制真空度不大于0.1MPa，以及控制干燥温度不大于60℃。In this embodiment, the degree of vacuum is controlled to be no greater than 0.1 MPa, and the drying temperature is controlled to be no greater than 60°C.
通过上述方式，本申请能够获得更均一、单分散性更好的铜颗粒，从而实现更加突出的物理性质，例如，通过小尺寸效应，进一步促进铜金属颗粒表面原子的扩散，使其能够在较低的温度下进行焊接，满足“低温烧结”的封装需求。Through the above method, the present application can obtain copper particles with more uniform and better monodispersity, so as to achieve more outstanding physical properties. Soldering at low temperature to meet the packaging requirements of "low temperature sintering".
请参阅图3，图3是本申请铜颗粒焊膏的烧结方法一实施方式的流程示意图。如图3所示，在本实施方式中，该方法包括：Please refer to FIG. 3 , which is a schematic flowchart of an embodiment of a method for sintering copper particle solder paste of the present application. As shown in Figure 3, in this embodiment, the method includes:
S31：按预设重量份准备以下原料：具有良好分散性的铜颗粒、分散剂、溶剂以及还原剂，其中，还原剂的重量份为0.5～5份。S31: Prepare the following raw materials according to preset weight parts: copper particles with good dispersibility, a dispersant, a solvent and a reducing agent, wherein the weight part of the reducing agent is 0.5-5 parts.
本实施方式中，准备以下按重量份计的原料：具有良好分散性的铜颗粒，75～90份；分散剂，1～5份；溶剂，10～15份；还原剂，0.5～5份。In this embodiment, the following raw materials are prepared in parts by weight: copper particles with good dispersibility, 75-90 parts; dispersant, 1-5 parts; solvent, 10-15 parts; reducing agent, 0.5-5 parts.
其中，以上各组份的总份数为100份。Wherein, the total number of the above components is 100 parts.
本实施方式中，还原剂包括抗坏血酸、甲酸铜、甲酸、乙酸以及丙酮肟中的至少一种。In this embodiment, the reducing agent includes at least one of ascorbic acid, copper formate, formic acid, acetic acid, and acetone oxime.
本实施方式中，分散剂包括聚乙烯吡咯烷酮K30、聚乙烯吡咯烷酮K90以及聚乙二醇1000中的任一种。In this embodiment, the dispersing agent includes any one of polyvinylpyrrolidone K30, polyvinylpyrrolidone K90 and polyethylene glycol 1000.
本实施方式中，溶剂包括乙二醇、二乙二醇、三乙二醇、聚乙二醇200、2-氨基-2-甲基-丙醇以及1-氨基-2-丙醇中的至少一种。In this embodiment, the solvent includes at least one of ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol 200, 2-amino-2-methyl-propanol and 1-amino-2-propanol A sort of.
S32：将还原剂、分散剂以及溶剂按原料配比混合并搅拌均匀，获得成膏体。S32: Mix the reducing agent, the dispersing agent and the solvent according to the raw material ratio and stir evenly to obtain a paste.
本实施方式中，当分散剂为聚乙烯吡咯烷酮K90或聚乙二醇1000时，将还 原剂、分散剂以及溶剂按原料配比混合并搅拌均匀，获得成膏体。In this embodiment, when the dispersing agent is polyvinylpyrrolidone K90 or polyethylene glycol 1000, the reducing agent, the dispersing agent and the solvent are mixed according to the raw material ratio and stirred to obtain a paste.
在其他实施方式中，当分散剂为聚乙烯吡咯烷酮K30时，将还原剂以及溶剂按原料配比混合并搅拌均匀，获得成膏体，本申请对此不作限定。In other embodiments, when the dispersant is polyvinylpyrrolidone K30, the reducing agent and the solvent are mixed according to the raw material ratio and stirred uniformly to obtain a paste, which is not limited in this application.
S33：将成膏体加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏。S33: Add the paste into the copper particles with good dispersibility according to the raw material ratio and stir evenly to obtain a copper particle solder paste.
本实施方式中，当分散剂为聚乙烯吡咯烷酮K90或聚乙二醇1000时，将含有聚乙烯吡咯烷酮K90或聚乙二醇1000的成膏体加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏。In this embodiment, when the dispersant is polyvinylpyrrolidone K90 or polyethylene glycol 1000, the paste containing polyvinylpyrrolidone K90 or polyethylene glycol 1000 is added to the copper particles with good dispersibility according to the ratio of raw materials And stir evenly to obtain copper particle solder paste.
在其他实施方式中，当分散剂为聚乙烯吡咯烷酮K30时，将成膏体与分散剂加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏。In other embodiments, when the dispersant is polyvinylpyrrolidone K30, the paste and dispersant are added to copper particles with good dispersibility according to the raw material ratio and stirred evenly to obtain copper particle solder paste.
S34：预通纯氮气，在氮气气氛下对铜颗粒焊膏进行回流焊，以获得致密连续的烧结层。S34: Pre-pass pure nitrogen, and reflow the copper particle solder paste in a nitrogen atmosphere to obtain a dense and continuous sintered layer.
本实施方式中，控制升温速率为1～20℃/min，控制烧结温度为250～300℃，以及控制烧结时间为30min。In this embodiment, the heating rate is controlled to be 1-20° C./min, the sintering temperature is controlled to be 250-300° C., and the sintering time is controlled to be 30 minutes.
进一步地，控制施加的压力为0.3～1MPa。Further, the applied pressure is controlled to be 0.3-1 MPa.
其中，在300℃下对铜颗粒焊膏进行烧结，获得的烧结强度约为20MPa～35MPa，与传统锡铅焊膏的烧结强度相当。Among them, when the copper particle solder paste is sintered at 300°C, the obtained sintering strength is about 20MPa-35MPa, which is equivalent to the sintering strength of traditional tin-lead solder paste.
具体地，回流焊(Reflow)是指通过重新熔化预先分配到印制板焊盘上的膏装软钎焊料，实现表面组装元器件焊端或引脚与印制板焊盘之间机械与电气连接的软钎焊。回流焊是靠气体在焊机内循环流动产生高温，从而对焊点产生作用，使胶状的焊剂在一定的高温气流下进行物理反应达到表面贴装器件(Surface Mounted Devices，SMD)的焊接。Specifically, reflow (Reflow) refers to remelting the paste solder pre-distributed to the printed board pads to achieve mechanical and Soldering of electrical connections. Reflow soldering relies on the circulating flow of gas in the welding machine to generate high temperature, thereby acting on the solder joints, so that the gelatinous flux undergoes a physical reaction under a certain high temperature airflow to achieve the welding of Surface Mounted Devices (SMD).
区别于现有技术，本实施方式中，由于铜颗粒焊膏中包括还原剂，故不仅能够去除铜颗粒表面的氧化层，还能够避免铜颗粒焊膏在保存以及使用过程中再次被氧化，故在烧结过程中无需添加氢气或甲酸等还原性气体进行保护；且由于铜颗粒表面未生成阻碍烧结过程的氧化层，故无需在高温高压下进行烧结，通过降低对烧结环境的要求，从而提升铜颗粒焊膏的应用范围；进一步地，本申请中的铜颗粒焊膏进行烧结后获得的烧结强度与传统锡铅焊膏相当，满足“低温烧结，高温服役”的封装需求，能够替代纳米银烧结焊膏或烧结型纳米银浆适用于电子封装和微连接领域。Different from the prior art, in this embodiment, since the copper particle solder paste includes a reducing agent, it can not only remove the oxide layer on the surface of the copper particle, but also prevent the copper particle solder paste from being oxidized again during storage and use. There is no need to add reducing gases such as hydrogen or formic acid for protection during the sintering process; and since there is no oxide layer on the surface of the copper particles that hinders the sintering process, it is not necessary to sinter under high temperature and high pressure. By reducing the requirements for the sintering environment, the copper Application range of particle solder paste; further, the sintering strength obtained by the copper particle solder paste in this application after sintering is equivalent to that of traditional tin-lead solder paste, which meets the packaging requirements of "low temperature sintering, high temperature service", and can replace nano-silver sintering Solder paste or sintered nano-silver paste is suitable for electronic packaging and micro-connection fields.
为便于对本申请实施例进行理解，本申请提供了以下非限制性实施例，对 本申请作进一步的详细说明。In order to facilitate the understanding of the embodiments of the present application, the present application provides the following non-limiting examples to further describe the present application in detail.
实施例1Example 1
准备以下按重量计的原料：具有良好分散性的铜颗粒，85份，其中，铜颗粒粒径为300nm；聚乙烯吡咯烷酮K90，0.5份；乙二醇，14份；抗坏血酸，0.5份；将抗坏血酸、聚乙烯吡咯烷酮K90以及乙二醇按原料配比混合并搅拌均匀，获得成膏体；将成膏体加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏；将铜颗粒焊膏用于铜背金硅晶片及铜基板的芯片粘接，预通纯氮气，在氮气气氛下对铜颗粒焊膏进行回流焊，加低压0.4MPa，控制温度为300℃，获取连接强度(剪切应力)为25MPa的连接接头。Prepare the following raw materials by weight: copper particles with good dispersibility, 85 parts, wherein the copper particles have a particle size of 300 nm; polyvinylpyrrolidone K90, 0.5 parts; ethylene glycol, 14 parts; ascorbic acid, 0.5 parts; , polyvinylpyrrolidone K90 and ethylene glycol are mixed according to the ratio of raw materials and stirred evenly to obtain a paste; the paste is added to the copper particles with good dispersibility according to the ratio of raw materials and stirred evenly to obtain a copper particle solder paste; The copper particle solder paste is used for chip bonding of copper-backed gold silicon wafer and copper substrate, and pure nitrogen is pre-passed, and the copper particle solder paste is reflowed under nitrogen atmosphere. The connection strength (shear stress) of the connection joint is 25 MPa.
用扫描电镜(SEM)观察实施例1中的铜颗粒在未与成膏体混合前的微观形貌特征，以及观察铜颗粒焊膏烧结后所获得的连接接头的微观形貌特征。Scanning electron microscope (SEM) was used to observe the micro-morphological characteristics of the copper particles in Example 1 before being mixed with the paste, and the micro-morphological characteristics of the connection joint obtained after the copper particle solder paste was sintered.
具体地，请参阅图4a与图4b，图4a与图4b是本申请实施例1中铜颗粒在不同阶段的SEM图；其中，图4a是本申请实施例1中铜颗粒在未与成膏体混合前的SEM图，图4b是本申请实施例1中铜颗粒焊膏烧结后所获得的连接接头的SEM图。Specifically, please refer to FIG. 4a and FIG. 4b. FIG. 4a and FIG. 4b are SEM images of copper particles at different stages in Example 1 of the present application; wherein, FIG. Figure 4b is the SEM image of the connection joint obtained after the copper particle solder paste is sintered in Example 1 of the present application.
由图4a与图4b可看出，纳米铜颗粒的小尺寸效应可以促进铜金属颗粒表面原子的扩散，使其能够在较低的温度下进行焊接，满足“低温烧结”的需求；加入了还原剂后，在较低温度下对铜颗粒焊膏进行烧结，烧结后形成的连接接头结构致密，颗粒的尺度效应消失，重熔温度恢复到块体金属的熔点，保证了铜颗粒焊膏的高温可靠性，满足“高温服役”的封装需求。It can be seen from Figure 4a and Figure 4b that the small size effect of nano-copper particles can promote the diffusion of atoms on the surface of copper metal particles, enabling it to be welded at a lower temperature to meet the requirements of "low temperature sintering"; adding reduction After sintering, the copper particle solder paste is sintered at a lower temperature. The joint structure formed after sintering is dense, the particle size effect disappears, and the remelting temperature returns to the melting point of the bulk metal, ensuring the high temperature of the copper particle solder paste. Reliability, to meet the packaging requirements of "high temperature service".
对比例1Comparative Example 1
准备以下按重量计的原料：具有良好分散性的铜颗粒，85份，其中，铜颗粒粒径为300nm；聚乙烯吡咯烷酮K90，1份；乙二醇，14份；将聚乙烯吡咯烷酮K90以及乙二醇按原料配比混合并搅拌均匀，获得成膏体；将成膏体加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏；将铜颗粒焊膏用于铜背金硅晶片及铜基板的芯片粘接，预通纯氮气，在氮气气氛下对铜颗粒焊膏进行回流焊，加低压0.4MPa，控制温度为300℃，获取连接强度(剪切应力)为8MPa的连接接头。The following raw materials by weight were prepared: copper particles with good dispersibility, 85 parts, wherein the copper particles had a particle size of 300 nm; polyvinylpyrrolidone K90, 1 part; ethylene glycol, 14 parts; Diols are mixed according to the ratio of raw materials and stirred evenly to obtain a paste; the paste is added to the copper particles with good dispersibility according to the ratio of raw materials and stirred evenly to obtain a copper particle solder paste; the copper particle solder paste is used for For chip bonding of copper-backed silicon wafer and copper substrate, pure nitrogen is pre-passed, and the copper particle solder paste is reflowed under nitrogen atmosphere, and the pressure is increased to 0.4MPa, and the temperature is controlled to 300 °C to obtain the connection strength (shear stress) 8MPa connection joint.
用扫描电镜(SEM)观察对比例1中铜颗粒焊膏烧结后所获得的连接接头的微观形貌特征。Scanning electron microscope (SEM) was used to observe the micro-morphological features of the connection joints obtained after sintering the copper particle solder paste in Comparative Example 1.
具体地，请参阅图5a与图5b，图5a与图5b是本申请实施例1与对比例1 中铜颗粒焊膏烧结后所获得的连接接头的SEM图的对比示意图；其中，图5a是本申请实施例1中铜颗粒焊膏烧结后所获得的连接接头的SEM图，图5b是本申请对比例1中铜颗粒焊膏烧结后所获得的连接接头的SEM图。Specifically, please refer to FIG. 5a and FIG. 5b. FIG. 5a and FIG. 5b are schematic diagrams showing the comparison of the SEM images of the connection joints obtained after the copper particle solder paste is sintered in Example 1 and Comparative Example 1 of the present application; wherein, FIG. 5a is a The SEM image of the connection joint obtained after the copper particle solder paste is sintered in Example 1 of the present application, and FIG. 5b is the SEM image of the connection joint obtained after the copper particle solder paste is sintered in Comparative Example 1 of the present application.
由图5a与图5b可看出，不包含还原剂的铜颗粒焊膏进行烧结后无法形成致密的结构，且烧结后获得的连接接头的强度仅为8MPa，远低于实施例1；由于对比例1烧结后的铜颗粒之间具有缝隙，颗粒感较强且颗粒的尺度效应并未消失，故无法恢复到块体金属的熔点，不能保证铜颗粒焊膏的高温可靠性，也就无法满足“高温服役”的封装需求。It can be seen from Figure 5a and Figure 5b that the copper particle solder paste without reducing agent cannot form a dense structure after sintering, and the strength of the connection joint obtained after sintering is only 8MPa, which is much lower than that of Example 1; There are gaps between the copper particles after sintering in ratio 1, the graininess is strong and the scale effect of the particles does not disappear, so it cannot restore the melting point of the bulk metal, and the high temperature reliability of the copper particle solder paste cannot be guaranteed, so it cannot meet the Packaging requirements for "high temperature service".
实施例2Example 2
准备以下按重量计的原料：具有良好分散性的铜颗粒，80份，其中，铜颗粒粒径为100nm；聚乙二醇1000，1份；三乙醇胺，14份；甲酸，5份；将甲酸、聚乙二醇1000以及三乙醇胺按原料配比混合并搅拌均匀，获得成膏体；将成膏体加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏；将铜颗粒焊膏用于铜板之间的粘接，预通纯氮气，在氮气气氛下对铜颗粒焊膏进行回流焊，加低压1MPa，控制温度为300℃，获取连接强度(剪切应力)为20MPa的连接接头。Prepare the following raw materials by weight: copper particles with good dispersibility, 80 parts, wherein the copper particles have a particle size of 100 nm; polyethylene glycol 1000, 1 part; triethanolamine, 14 parts; formic acid, 5 parts; , polyethylene glycol 1000 and triethanolamine are mixed according to the ratio of raw materials and stirred evenly to obtain a paste; the paste is added to the copper particles with good dispersibility according to the ratio of raw materials and stirred evenly to obtain copper particle solder paste; Use copper particle solder paste for bonding between copper plates, pre-pure pure nitrogen, reflow the copper particle solder paste in a nitrogen atmosphere, apply a low pressure of 1MPa, and control the temperature to 300°C to obtain the connection strength (shear stress) 20MPa connection joint.
用扫描电镜(SEM)观察实施例2中铜颗粒焊膏烧结后所获得的连接接头的微观形貌特征，所获得的SEM图与实施例1中铜颗粒焊膏烧结后所获得的连接接头的SEM图相似，表明加入甲酸作为还原剂后，铜颗粒焊膏的抗氧化性能与加入抗坏血酸时的氧化性能一致。Scanning electron microscope (SEM) was used to observe the micro-morphological characteristics of the connection joint obtained after sintering the copper particle solder paste in Example 2. The obtained SEM image was the same as that of the connection joint obtained after the copper particle solder paste was sintered in Example 1. The SEM images are similar, indicating that the oxidation resistance of the copper particle solder paste after adding formic acid as a reducing agent is consistent with that when adding ascorbic acid.
实施例3Example 3
准备以下按重量计的原料：具有良好分散性的铜颗粒，82份，其中，铜颗粒粒径为300nm；聚乙二醇1000，1份；三乙二醇，15份；抗坏血酸，2份；将抗坏血酸、聚乙二醇1000以及三乙二醇按原料配比混合并搅拌均匀，获得成膏体；将成膏体加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏；将铜颗粒焊膏用于碳化硅(SiC)芯片及陶瓷覆铜板(Direct Bonding Copper，DBC)之间的连接，预通纯氮气，在氮气气氛下对铜颗粒焊膏进行回流焊，加低压0.7MPa，控制温度为300℃，获取连接强度(剪切应力)为34MPa的连接接头。Prepare the following raw materials by weight: copper particles with good dispersibility, 82 parts, wherein the particle size of the copper particles is 300 nm; polyethylene glycol 1000, 1 part; triethylene glycol, 15 parts; ascorbic acid, 2 parts; Mix ascorbic acid, polyethylene glycol 1000 and triethylene glycol according to the ratio of raw materials and stir evenly to obtain a paste; add the paste into copper particles with good dispersibility according to the ratio of raw materials and stir evenly to obtain copper Particle solder paste; copper particle solder paste is used for the connection between silicon carbide (SiC) chips and ceramic copper clad laminates (Direct Bonding Copper, DBC), and pure nitrogen is pre-passed, and the copper particle solder paste is reflowed under nitrogen atmosphere. , the pressure is 0.7MPa, and the temperature is controlled at 300°C to obtain a connection joint with a connection strength (shear stress) of 34MPa.
实施例4Example 4
准备以下按重量计的原料：具有良好分散性的铜颗粒，82份，其中，铜颗 粒粒径为300nm；聚乙二醇1000，1份；三乙二醇，15份；抗坏血酸，2份；将抗坏血酸、聚乙二醇1000以及三乙二醇按原料配比混合并搅拌均匀，获得成膏体；将成膏体加入按原料配比的具有良好分散性的铜颗粒中并搅拌均匀，获得铜颗粒焊膏；将铜颗粒焊膏用于碳化硅(SiC)芯片及陶瓷覆铜板(Direct Bonding Copper，DBC)之间的连接，在甲酸气氛下对铜颗粒焊膏进行回流焊，加低压0.7MPa，控制温度为300℃，获取连接强度(剪切应力)为30MPa的连接接头。Prepare the following raw materials by weight: copper particles with good dispersibility, 82 parts, wherein the particle size of the copper particles is 300 nm; polyethylene glycol 1000, 1 part; triethylene glycol, 15 parts; ascorbic acid, 2 parts; Mix ascorbic acid, polyethylene glycol 1000 and triethylene glycol according to the ratio of raw materials and stir evenly to obtain a paste; add the paste into copper particles with good dispersibility according to the ratio of raw materials and stir evenly to obtain copper Particle solder paste; copper particle solder paste is used for the connection between silicon carbide (SiC) chips and ceramic copper clad laminates (Direct Bonding Copper, DBC), and the copper particle solder paste is reflowed under formic acid atmosphere, and the low pressure is 0.7MPa , control the temperature to 300 ℃, and obtain the connection joint with the connection strength (shear stress) of 30MPa.
针对实施例3与实施例4，用扫描电镜(SEM)分别观察实施例3与实施例4中铜颗粒焊膏烧结后所获得的连接接头的微观形貌特征。For Example 3 and Example 4, scanning electron microscopy (SEM) was used to observe the microscopic features of the connection joints obtained after sintering the copper particle solder paste in Example 3 and Example 4, respectively.
具体地，请参阅图6a与图6b，图6a与图6b是本申请实施例3与实施例4中铜颗粒焊膏烧结后所获得的连接接头的SEM图的对比示意图；其中，图6a是本申请实施例3中铜颗粒焊膏烧结后所获得的连接接头的SEM图，图6b是本申请实施例4中铜颗粒焊膏烧结后所获得的连接接头的SEM图。Specifically, please refer to FIG. 6a and FIG. 6b. FIG. 6a and FIG. 6b are schematic diagrams showing the comparison of the SEM images of the connection joints obtained after the copper particle solder paste is sintered in Example 3 and Example 4 of the present application; wherein, FIG. 6a is a The SEM image of the connection joint obtained after the copper particle solder paste is sintered in Example 3 of the present application, and FIG. 6b is the SEM image of the connection joint obtained after the copper particle solder paste is sintered in Example 4 of the present application.
由图6a与图6b可看出，实施例3与实施例4中的铜颗粒焊膏烧结后所形成的连接接头均具有致密的结构，表明在铜颗粒焊膏中加入还原剂后，焊膏在烧结时无需还原性气体保护也能形成强度相当的连接结构。It can be seen from Figure 6a and Figure 6b that the connection joints formed after the copper particle solder pastes in Example 3 and Example 4 are sintered have dense structures, indicating that after adding a reducing agent to the copper particle solder paste, the solder paste During sintering, a connection structure with comparable strength can be formed without reducing gas protection.
以上所述仅为本申请的实施方式，并非因此限制本申请的专利范围，凡是利用本申请说明书及附图内容所作的等效结构或等效流程变换，或直接或间接运用在其他相关的技术领域，均同理包括在本申请的专利保护范围内。The above description is only an embodiment of the present application, and is not intended to limit the scope of the patent of the present application. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present application, or directly or indirectly applied to other related technologies Fields are similarly included within the scope of patent protection of this application.

Claims (20)

  1. 一种铜颗粒焊膏，包括具有良好分散性的铜颗粒、分散剂以及溶剂，其特征在于，所述铜颗粒焊膏还包括还原剂，其中，所述还原剂的重量份为0.5～5份。A copper particle solder paste, comprising copper particles with good dispersibility, a dispersant and a solvent, characterized in that the copper particle solder paste further includes a reducing agent, wherein the weight part of the reducing agent is 0.5-5 parts .
  2. 根据权利要求1所述的铜颗粒焊膏，其特征在于，所述还原剂包括抗坏血酸、甲酸铜、甲酸、乙酸以及丙酮肟中的至少一种。The copper particle solder paste according to claim 1, wherein the reducing agent comprises at least one of ascorbic acid, copper formate, formic acid, acetic acid and acetone oxime.
  3. 根据权利要求1所述的铜颗粒焊膏，其特征在于，所述铜颗粒的粒径为100～300nm。The copper particle solder paste according to claim 1, wherein the particle size of the copper particles is 100-300 nm.
  4. 根据权利要求3所述的铜颗粒焊膏，其特征在于，所述铜颗粒为球型。The copper particle solder paste according to claim 3, wherein the copper particles are spherical.
  5. 根据权利要求1所述的铜颗粒焊膏，其特征在于，所述分散剂包括聚乙烯吡咯烷酮K30、聚乙烯吡咯烷酮K90以及聚乙二醇1000中的任一种。The copper particle solder paste according to claim 1, wherein the dispersing agent comprises any one of polyvinylpyrrolidone K30, polyvinylpyrrolidone K90 and polyethylene glycol 1000.
  6. 根据权利要求1所述的铜颗粒焊膏，其特征在于，所述溶剂包括乙二醇、二乙二醇、三乙二醇、聚乙二醇200、2-氨基-2-甲基-丙醇以及1-氨基-2-丙醇中的至少一种。The copper particle solder paste according to claim 1, wherein the solvent comprises ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol 200, 2-amino-2-methyl-propane At least one of alcohol and 1-amino-2-propanol.
  7. 一种铜颗粒焊膏的制备方法，其特征在于，包括以下步骤：A preparation method of copper particle solder paste is characterized in that, comprises the following steps:
    对铜颗粒进行分散处理，获得具有良好分散性的铜颗粒；Disperse the copper particles to obtain copper particles with good dispersibility;
    按预设重量份准备以下原料：所述具有良好分散性的铜颗粒、分散剂、溶剂以及还原剂，其中，所述还原剂的重量份为0.5～5份；Prepare the following raw materials according to preset weight parts: the copper particles with good dispersibility, a dispersant, a solvent and a reducing agent, wherein the weight part of the reducing agent is 0.5-5 parts;
    将所述还原剂、所述分散剂以及所述溶剂按原料配比混合并搅拌均匀，获得成膏体；Mixing the reducing agent, the dispersing agent and the solvent according to the ratio of raw materials and stirring evenly to obtain a paste;
    将所述成膏体加入所述按原料配比的所述具有良好分散性的铜颗粒中并搅拌均匀，获得所述铜颗粒焊膏。The paste is added to the copper particles with good dispersibility according to the raw material ratio and stirred uniformly to obtain the copper particle solder paste.
  8. 根据权利要求7所述的铜颗粒焊膏的制备方法，其特征在于，所述对铜颗粒进行分散处理，获得具有良好分散性的铜颗粒的步骤具体包括：The method for preparing copper particle solder paste according to claim 7, wherein the step of dispersing the copper particles to obtain copper particles with good dispersibility specifically comprises:
    按预设重量份准备以下原料：所述铜颗粒、无水乙醇，以及所述分散剂；Prepare the following raw materials according to preset weight parts: the copper particles, anhydrous ethanol, and the dispersant;
    将所述铜颗粒以及所述分散剂按原料配比加入按原料配比的所述无水乙醇中，获得混合液体；The copper particles and the dispersant are added to the dehydrated ethanol according to the raw material ratio to obtain a mixed liquid;
    将所述混合液体超声分散至少30分钟，获得分散液；ultrasonically dispersing the mixed liquid for at least 30 minutes to obtain a dispersion;
    对所述分散液进行真空干燥，获得所述具有良好分散性的铜颗粒。The dispersion liquid is vacuum-dried to obtain the copper particles with good dispersibility.
  9. 根据权利要求8所述的铜颗粒焊膏的制备方法，其特征在于，所述对所述分散液进行真空干燥，获得所述具有良好分散性的铜颗粒的步骤还包括：The method for preparing copper particle solder paste according to claim 8, wherein the step of vacuum drying the dispersion to obtain the copper particles with good dispersibility further comprises:
    控制真空度不大于0.1MPa。Control the vacuum degree not more than 0.1MPa.
  10. 根据权利要求9所述的铜颗粒焊膏的制备方法，其特征在于，所述对所述分散液进行真空干燥，获得所述具有良好分散性的铜颗粒的步骤进一步包括：The method for preparing copper particle solder paste according to claim 9, wherein the step of vacuum drying the dispersion to obtain the copper particles with good dispersibility further comprises:
    控制干燥温度不大于60℃。Control the drying temperature not more than 60 ℃.
  11. 根据权利要求10所述的铜颗粒焊膏的制备方法，其特征在于，所述将所述混合液体超声分散至少30分钟，获得分散液的步骤具体包括：The method for preparing copper particle solder paste according to claim 10, wherein the step of ultrasonically dispersing the mixed liquid for at least 30 minutes to obtain the dispersion liquid specifically comprises:
    将所述混合液体置于超声场中，进行超声分散至少30分钟，以获得所述分散液。The mixed liquid is placed in an ultrasonic field, and ultrasonic dispersion is performed for at least 30 minutes to obtain the dispersion liquid.
  12. 根据权利要求7所述的铜颗粒焊膏的制备方法，其特征在于，所述将所述成膏体加入所述按原料配比的所述具有良好分散性的铜颗粒中并搅拌均匀，获得所述铜颗粒焊膏的步骤具体包括：The method for preparing copper particle solder paste according to claim 7, wherein the paste is added to the copper particles with good dispersibility according to the raw material ratio and stirred uniformly to obtain The steps of the copper particle solder paste specifically include:
    将所述成膏体加入所述按原料配比的所述具有良好分散性的铜颗粒中，使用混合设备对所述铜颗粒以及所述成膏体进行搅拌至均匀，以获得所述铜颗粒焊膏。Adding the paste into the copper particles with good dispersibility according to the raw material ratio, and using a mixing device to stir the copper particles and the paste until uniform, so as to obtain the copper particles solder paste.
  13. 根据权利要求12所述的铜颗粒焊膏的制备方法，其特征在于，The preparation method of copper particle solder paste according to claim 12, wherein,
    所述混合设备包括行星式混料机。The mixing equipment includes a planetary mixer.
  14. 根据权利要求13所述的铜颗粒焊膏的制备方法，其特征在于，The method for preparing copper particle solder paste according to claim 13, wherein,
    所述混合设备的混合速度为2000rpm。The mixing speed of the mixing device was 2000 rpm.
  15. 一种铜颗粒焊膏的制备方法，其特征在于，包括以下步骤：A preparation method of copper particle solder paste is characterized in that, comprises the following steps:
    对铜颗粒进行分散处理，获得具有良好分散性的铜颗粒；Disperse the copper particles to obtain copper particles with good dispersibility;
    按预设重量份准备以下原料：所述具有良好分散性的铜颗粒、分散剂、溶剂以及还原剂，其中，所述还原剂的重量份为0.5～5份；Prepare the following raw materials according to preset weight parts: the copper particles with good dispersibility, a dispersant, a solvent and a reducing agent, wherein the weight part of the reducing agent is 0.5-5 parts;
    将所述还原剂以及所述溶剂按原料配比混合并搅拌均匀，获得成膏体；Mixing the reducing agent and the solvent according to the raw material ratio and stirring evenly to obtain a paste;
    将所述成膏体以及所述分散剂加入所述按原料配比的所述具有良好分散性的铜颗粒中并搅拌均匀，获得所述铜颗粒焊膏。The paste and the dispersant are added to the copper particles with good dispersibility according to the raw material ratio and stirred uniformly to obtain the copper particle solder paste.
  16. 一种铜颗粒焊膏的烧结方法，其特征在于，包括：A method for sintering copper particle solder paste, comprising:
    按预设重量份准备以下原料：具有良好分散性的铜颗粒、分散剂、溶剂以及还原剂，其中，所述还原剂的重量份为0.5～5份；Prepare the following raw materials according to preset weight parts: copper particles with good dispersibility, dispersant, solvent and reducing agent, wherein the weight part of the reducing agent is 0.5-5 parts;
    将所述还原剂、所述分散剂以及所述溶剂按原料配比混合并搅拌均匀，获得成膏体；Mixing the reducing agent, the dispersing agent and the solvent according to the ratio of raw materials and stirring evenly to obtain a paste;
    将所述成膏体加入所述按原料配比的所述具有良好分散性的铜颗粒中并搅拌均匀，获得所述铜颗粒焊膏；adding the paste into the copper particles with good dispersibility according to the ratio of raw materials and stirring evenly to obtain the copper particle solder paste;
    预通纯氮气，在氮气气氛下对所述铜颗粒焊膏进行回流焊，以获得致密连续的烧结层。Pure nitrogen gas is pre-passed, and the copper particle solder paste is reflowed in a nitrogen atmosphere to obtain a dense and continuous sintered layer.
  17. 根据权利要求16所述的铜颗粒焊膏的烧结方法，其特征在于，所述预通纯氮气，在氮气气氛下对所述铜颗粒焊膏进行回流焊，以获得致密连续的烧结层的步骤包括：The method for sintering copper particle solder paste according to claim 16, wherein the step of pre-passing pure nitrogen gas and reflow soldering the copper particle solder paste in a nitrogen atmosphere to obtain a dense and continuous sintered layer include:
    控制升温速率为1～20℃/min。The heating rate is controlled to be 1 to 20°C/min.
  18. 根据权利要求17所述的铜颗粒焊膏的烧结方法，其特征在于，所述预通纯氮气，在氮气气氛下对所述铜颗粒焊膏进行回流焊，以获得致密连续的烧结层的步骤还包括：The method for sintering copper particle solder paste according to claim 17, wherein the step of pre-passing pure nitrogen gas and reflow soldering the copper particle solder paste in a nitrogen atmosphere to obtain a dense and continuous sintered layer Also includes:
    控制烧结温度为250～300℃。The sintering temperature is controlled to be 250-300°C.
  19. 根据权利要求18所述的铜颗粒焊膏的烧结方法，其特征在于，所述预通纯氮气，在氮气气氛下对所述铜颗粒焊膏进行回流焊，以获得致密连续的烧结层的步骤进一步包括：The method for sintering copper particle solder paste according to claim 18, wherein the step of pre-passing pure nitrogen gas and reflow soldering the copper particle solder paste in a nitrogen atmosphere to obtain a dense and continuous sintered layer Further includes:
    控制烧结时间为30min。Control the sintering time to 30min.
  20. 根据权利要求19所述的铜颗粒焊膏的烧结方法，其特征在于，所述预通纯氮气，在氮气气氛下对所述铜颗粒焊膏进行回流焊，以获得致密连续的烧结层的步骤还包括：The method for sintering copper particle solder paste according to claim 19, wherein the step of pre-passing pure nitrogen gas and reflow soldering the copper particle solder paste in a nitrogen atmosphere to obtain a dense and continuous sintered layer Also includes:
    控制施加的压力为0.3～1MPa。The applied pressure is controlled to be 0.3 to 1 MPa.
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