A heat dissipation material for electronic packaging and a method for preparing the same

Abstract

The application provides a heat dissipation material for electronic packaging and a preparation method thereof, and belongs to the technical field of heat dissipation materials. After tourmaline is subjected to ball milling and cleaning treatment, the surface of the tourmaline is coated with a layer of tungsten-copper-silver alloy, and a layer of graphene oxide is further deposited on the surface; after reduction by hydrazine hydrate, modified nanoballs are obtained; the modified nanoballs are uniformly mixed with red copper powder, ball milled, cold-pressed, and sintered at high temperature and high pressure to obtain the heat dissipation material for electronic packaging. The application prepares a heat dissipation material for electronic packaging with high heat dissipation and high mechanical properties, and the heat dissipation material has higher thermal conductivity than a traditional heat dissipation substrate, so that heat can be directly dissipated through the substrate in SiP packaging, thick mold packaging and high heat dissipation packaging technology, the heat transfer path is shortened, the heat dissipation effect is enhanced, and the application range is wider.

Description

Technical Field

[0001] This invention relates to the field of heat dissipation materials technology, specifically to a heat dissipation material for electronic packaging and its preparation method. Background Technology

[0002] With the advancement of modern power electronics technology, electrical products are trending towards miniaturization and compactness, leading to increased power and heat dissipation requirements for electronic devices. If the heat dissipated by electronic devices during operation cannot be dissipated in time, it can easily cause localized high temperatures, which can shorten the lifespan of the devices or even affect their performance. As the heat flux density inside advanced microelectronic chips increases, the requirements for the thermal conductivity of materials are also becoming increasingly stringent to ensure effective heat dissipation. Statistics show that 55% of electronic device failures are caused by excessive temperature, with overheating being the primary failure mode. Therefore, developing high-heat-dissipation electronic packaging materials is crucial for improving the reliability of electronic products.

[0003] Currently, common ceramic substrate heat dissipation materials include Al2O3, aluminum nitride, SiC, BeO, and Si3N4. Al2O3 and BeO ceramics are two main substrate materials for high-power packaging. However, both of these substrate materials have inherent drawbacks. Al2O3 has low thermal conductivity (20 W / (K·M)) and its coefficient of thermal expansion is not compatible with the chip material. Although BeO has excellent overall performance, its production cost is high and it is highly toxic. Considering performance, cost, and environmental protection, neither of these materials can be used as an ideal heat dissipation substrate material. Summary of the Invention

[0004] The purpose of this invention is to propose a heat dissipation material for electronic packaging and its preparation method. Compared with traditional heat dissipation substrates, it has higher thermal conductivity, which enables heat to be dissipated directly through the substrate in SiP packaging, thick mold packaging and high heat dissipation packaging technologies, shortening the heat transfer path, enhancing the heat dissipation effect, and expanding its application range.

[0005] The technical solution of this invention is implemented as follows:

[0006] This invention provides a method for preparing a heat dissipation material for electronic packaging. Tourmaline is ball-milled and cleaned, then coated with a tungsten-copper-silver alloy layer. A layer of graphene oxide is then deposited on the surface. After reduction with hydrazine hydrate, modified nanospheres are obtained. These nanospheres are then mixed evenly with copper powder, ball-milled, cold-pressed, and sintered under high temperature and high pressure to obtain the heat dissipation material for electronic packaging.

[0007] As a further improvement to the present invention, the following steps are included:

[0008] S1. Processing of tourmaline: Tourmaline is crushed, ball-milled, sieved, washed, and dried to obtain ultrafine tourmaline powder;

[0009] S2. Tungsten-copper-silver alloy coating: The tourmaline ultrafine powder obtained in step S1 is added to water, sodium tungstate, copper salt and silver salt are added, a complexing agent is added, the mixture is stirred and reacted, the solvent is heated and evaporated to obtain a sol; then the temperature is increased and the vacuum degree is decreased to obtain a dry gel, which is taken out, calcined, ball-milled, and reduced by low-temperature hydrogen to obtain tungsten-copper-silver alloy coated tourmaline nanospheres;

[0010] S3. Graphene oxide coating: Graphene oxide is dissolved in water, and tungsten-copper-silver alloy coated tourmaline nanospheres obtained in step S2 are added. The mixture is stirred ultrasonically, centrifuged, washed, and dried to obtain graphene oxide / tungsten-copper-silver alloy coated tourmaline nanospheres.

[0011] S4. Reduction: Add the modified nanospheres obtained in step S3 to water, add hydrazine hydrate and ammonia, heat and stir to react, centrifuge, wash, and dry to obtain modified nanospheres;

[0012] S5. Preparation of heat dissipation material for electronic packaging: The modified nanospheres and copper powder obtained in step S4 are mixed evenly, ball-milled, cold-pressed, and sintered at high temperature and high pressure at a pressure of 1-3 GPa and a temperature of 900-1100℃ to obtain heat dissipation material for electronic packaging.

[0013] As a further improvement of the present invention, the ball milling time in step S1 is 2-4 hours, the sieve mesh size is 300-700 nm, and the cleaning is performed by adding ethanol and ultrasonic treatment at 1000-1200W for 20-30 minutes.

[0014] As a further improvement of the present invention, in step S2, the mass ratio of tourmaline ultrafine powder, sodium tungstate, copper salt, silver salt, and complexing agent is 20-30:7-10:3-5:7-10:40-50, the copper salt is selected from at least one of copper chloride, copper sulfate, and copper nitrate, the silver salt is silver nitrate, the stirring reaction time is 20-30 min, the complexing agent is selected from at least one of citric acid and sodium citrate, the heating temperature is 45-65℃, the temperature is increased to the heater temperature of 130-140℃, and the vacuum degree is reduced to 0.01-0.1 MPa; the ball milling time is 3-5 h; the low-temperature hydrogen reduction is carried out in a strong drainage permeable tube furnace at 650-700℃ for 3-5 h with hydrogen gas introduced, and the hydrogen gas flow rate is 15-20 L / min; the calcination temperature is 800-1000℃ and the time is 2-4 h.

[0015] As a further improvement of the present invention, the mass ratio of graphene oxide and tungsten-copper-silver alloy-coated tourmaline nanospheres in step S3 is 12-15:20-25, the power of the ultrasonic stirring reaction is 1000-1500W, and the time is 20-30min.

[0016] As a further improvement of the present invention, the mass ratio of the modified nanospheres, hydrazine hydrate and ammonia in step S4 is 10:3-5:2-4, the concentration of the ammonia is 22-25wt%, the temperature of the heating and stirring reaction is 80-90℃, and the time is 2-4h.

[0017] As a further improvement of the present invention, the mass ratio of modified nanospheres to copper powder in step S5 is 7-10:2-3, the ball milling speed is 150-200 r / min and the time is 1-2 h, the cold pressing pressure is 55-60 MPa and the time is 1-2 min, and the high temperature and high pressure sintering time is 10-20 min.

[0018] As a further improvement to the present invention, the specific steps include:

[0019] S1. Treatment of tourmaline: The tourmaline is crushed, ball-milled for 2-4 hours, sieved, the sieve has a pore size of 300-700nm, added to ethanol, ultrasonically cleaned at 1000-1200W for 20-30 minutes, and dried to obtain tourmaline ultrafine powder.

[0020] S2. Tungsten-copper-silver alloy coating: 20-30 parts by weight of the tourmaline ultrafine powder obtained in step S1 are added to 500 parts by weight of water, 7-10 parts by weight of sodium tungstate, 3-5 parts by weight of copper salt and 7-10 parts by weight of silver salt are added, and 40-50 parts by weight of complexing agent are added. The mixture is stirred and reacted for 20-30 minutes, heated to 45-65℃, and the solvent is evaporated to obtain a sol. Then the temperature is raised to the heater temperature of 130-140℃, the vacuum degree is reduced to 0.01-0.1MPa, and the reaction is carried out for 1-2 hours to obtain a dry gel. The gel is taken out, calcined at 800-1000℃ for 2-4 hours, ball-milled for 3-5 hours, and reduced with hydrogen gas at 650-700℃ in a strong drainage and permeable tube furnace for 3-5 hours with a hydrogen gas flow rate of 15-20 L / min to obtain tungsten-copper-silver alloy coated tourmaline nanospheres.

[0021] S3. Graphene oxide coating: Dissolve 12-15 parts by weight of graphene oxide in 500 parts by weight of water, add 20-25 parts by weight of tungsten-copper-silver alloy coated tourmaline nanospheres obtained in step S2, stir ultrasonically at 1000-1500W for 20-30 min, centrifuge, wash, and dry to obtain graphene oxide / tungsten-copper-silver alloy coated tourmaline nanospheres;

[0022] S4. Reduction: Add 10 parts by weight of the modified nanospheres obtained in step S3 to 200 parts by weight of water, add 3-5 parts by weight of hydrazine hydrate and 2-4 parts by weight of 22-25 wt% ammonia water, heat to 80-90℃, stir and react for 2-4 hours, centrifuge, wash, and dry to obtain modified nanospheres.

[0023] S5. Preparation of heat dissipation material for electronic packaging: 70-100 parts by weight of the modified nanospheres obtained in step S4 and 20-30 parts by weight of copper powder are mixed evenly, ball-milled at 150-200 r / min for 1-2 h, cold-pressed at 55-60 MPa for 1-2 min, and sintered at 1-3 GPa and 900-1100℃ for 10-20 min to obtain the heat dissipation material for electronic packaging.

[0024] The present invention further protects a heat dissipation material for electronic packaging prepared by the above-described preparation method.

[0025] This invention further protects the application of the above-mentioned heat dissipation material for electronic packaging in SiP packaging, thick mold packaging, and high heat dissipation packaging technologies.

[0026] The present invention has the following beneficial effects:

[0027] Tourmaline has excellent radiative heat dissipation properties, emitting far-infrared electromagnetic waves with wavelengths of 4-14μm and an infrared emissivity greater than 0.92. Furthermore, its emissivity is further enhanced after high-temperature calcination. Simultaneously, with tourmaline as the core material, it can spontaneously and continuously generate DC static electricity under the influence of its own electrostatic field, constantly releasing electrons. These electrons act as heat carriers, continuously carrying away heat and thus accelerating heat dissipation.

[0028] This invention involves crushing and ball milling tourmaline to obtain nanoscale tourmaline ultrafine powder. Using this tourmaline ultrafine powder as the core, a sol-gel reaction is carried out on the surface, followed by calcination to coat the surface with a layer of W-Cu-Ag oxide. Through low-temperature hydrogen reduction, tungsten-copper-silver alloy-coated tourmaline nanospheres are obtained. This tungsten-copper-silver alloy has extremely high thermal conductivity, which can further improve the heat dissipation performance of the obtained nanospheres.

[0029] The modified nanospheres are further coated with a layer of graphene oxide and then reduced with hydrazine hydrate. This results in a layer of graphite with high thermal conductivity on top of a tungsten-copper-silver alloy coating. This further improves the thermal conductivity of the nanospheres and enhances the interfacial bonding of the tungsten-copper-silver alloy, making the alloy more tightly bonded. Consequently, the mechanical properties of the resulting heat dissipation material are also improved.

[0030] The modified nanospheres were mixed with copper powder, pressed, and calcined to obtain a heat dissipation material. During ball milling, the rotation speed was 150-200 r / min to prevent the particles from colliding with each other and inevitably tending to combine, leading to agglomeration and clumping. This resulted in a heat dissipation material with high heat dissipation and high mechanical properties for electronic packaging. Compared with the heat dissipation substrate, it has a higher thermal conductivity, which allows heat to be dissipated directly through the substrate in SiP packaging, thick mold packaging, and high heat dissipation packaging technologies, shortening the heat transfer path, enhancing the heat dissipation effect, and broadening its application range. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] The copper powder is a high thermal conductivity T2 copper powder with spherical particles, a particle size of 35-40 μm, and a purity of not less than 99.9%. The tourmaline is tourmaline powder from Altay, Xinjiang, with a particle size of 35-40 μm and a chemical formula of NaFe3Al6Si6O. 18 (BO3)3(OH)4. Example 1

[0033] This embodiment provides a method for preparing a heat dissipation material for electronic packaging, specifically including the following steps:

[0034] S1. Treatment of tourmaline: The tourmaline is crushed, ball-milled for 2 hours, sieved (the sieve has a pore size of 300 nm), added to ethanol, ultrasonically cleaned at 1000 W for 20 minutes, and dried to obtain tourmaline ultrafine powder.

[0035] S2. Tungsten-copper-silver alloy coating: 20 parts by weight of tourmaline ultrafine powder obtained in step S1 were added to 500 parts by weight of water, 7 parts by weight of sodium tungstate, 3 parts by weight of copper chloride and 7 parts by weight of silver nitrate were added, and 40 parts by weight of citric acid were added. The mixture was stirred and reacted for 20 min, heated to 45°C, and the solvent was evaporated to obtain a sol. Then the temperature was raised to 130°C and the vacuum was reduced to 0.01 MPa. The mixture was reacted for 1 h to obtain a dry gel. The gel was taken out, calcined at 800°C for 2 h, ball-milled for 3 h, and reduced with hydrogen at 650°C in a high-drainage and permeable tube furnace for 3 h with a hydrogen flow rate of 15 L / min to obtain tungsten-copper-silver alloy coated tourmaline nanospheres.

[0036] S3. Graphene oxide coating: 12 parts by weight of graphene oxide were dissolved in 500 parts by weight of water, and 20 parts by weight of tungsten-copper-silver alloy coated tourmaline nanospheres obtained in step S2 were added. The mixture was stirred by ultrasonication at 1000W for 20 minutes, centrifuged, washed, and dried to obtain graphene oxide / tungsten-copper-silver alloy coated tourmaline nanospheres.

[0037] S4. Reduction: Add 10 parts by weight of the modified nanospheres obtained in step S3 to 200 parts by weight of water, add 3 parts by weight of hydrazine hydrate and 2 parts by weight of 22wt% ammonia water, heat to 80℃, stir and react for 2 hours, centrifuge, wash, and dry to obtain modified nanospheres.

[0038] S5. Preparation of heat dissipation material for electronic packaging: 70 parts by weight of the modified nanospheres obtained in step S4 and 20 parts by weight of copper powder were stirred and mixed for 20 min, ball milled at 150 r / min for 1 h, cold pressed at 55 MPa for 1 min, and sintered at 1 GPa and 900℃ for 10 min to obtain the heat dissipation material for electronic packaging. Example 2

[0039] This embodiment provides a method for preparing a heat dissipation material for electronic packaging, specifically including the following steps:

[0040] S1. Treatment of tourmaline: The tourmaline was crushed, ball-milled for 4 hours, sieved (the sieve has a pore size of 700 nm), added to ethanol, ultrasonically cleaned at 1200 W for 30 minutes, and dried to obtain tourmaline ultrafine powder.

[0041] S2. Tungsten-copper-silver alloy coating: 30 parts by weight of tourmaline ultrafine powder obtained in step S1 were added to 500 parts by weight of water, 10 parts by weight of sodium tungstate, 5 parts by weight of copper sulfate and 10 parts by weight of silver nitrate were added, and 50 parts by weight of sodium citrate were added. The mixture was stirred and reacted for 30 min, heated to 65 °C, and the solvent was evaporated to obtain a sol. Then the temperature was raised to the heater temperature of 140 °C, the vacuum degree was reduced to 0.1 MPa, and the reaction was carried out for 2 h to obtain a dry gel. The gel was taken out, calcined at 1000 °C for 4 h, ball-milled for 5 h, and reduced with hydrogen gas at 700 °C for 5 h in a tube furnace with strong drainage and permeability. The hydrogen gas flow rate was 20 L / min to obtain tungsten-copper-silver alloy coated tourmaline nanospheres.

[0042] S3. Graphene oxide coating: 15 parts by weight of graphene oxide were dissolved in 500 parts by weight of water, and 25 parts by weight of tungsten-copper-silver alloy coated tourmaline nanospheres obtained in step S2 were added. The mixture was stirred by ultrasonication at 1500W for 30 minutes, centrifuged, washed, and dried to obtain graphene oxide / tungsten-copper-silver alloy coated tourmaline nanospheres.

[0043] S4. Reduction: Add 10 parts by weight of the modified nanospheres obtained in step S3 to 200 parts by weight of water, add 5 parts by weight of hydrazine hydrate and 4 parts by weight of 25 wt% ammonia water, heat to 90°C, stir and react for 4 hours, centrifuge, wash, and dry to obtain modified nanospheres.

[0044] S5. Preparation of heat dissipation material for electronic packaging: 100 parts by weight of the modified nanospheres obtained in step S4 and 30 parts by weight of copper powder were stirred and mixed for 20 min, ball milled at 200 r / min for 2 h, cold pressed at 60 MPa for 2 min, and sintered at 3 GPa and 1100℃ for 20 min to obtain heat dissipation material for electronic packaging. Example 3

[0045] This embodiment provides a method for preparing a heat dissipation material for electronic packaging, specifically including the following steps:

[0046] S1. Treatment of tourmaline: The tourmaline is crushed, ball-milled for 3 hours, sieved (the sieve has a pore size of 500 nm), added to ethanol, ultrasonically cleaned at 1100 W for 25 minutes, and dried to obtain tourmaline ultrafine powder.

[0047] S2. Tungsten-copper-silver alloy coating: 25 parts by weight of tourmaline ultrafine powder obtained in step S1 were added to 500 parts by weight of water, 8 parts by weight of sodium tungstate, 4 parts by weight of copper nitrate and 8 parts by weight of silver nitrate were added, and 45 parts by weight of citric acid were added. The mixture was stirred and reacted for 25 min, heated to 55 °C, and the solvent was evaporated to obtain a sol. Then the temperature was raised to the heater temperature of 135 °C, the vacuum degree was reduced to 0.05 MPa, and the reaction was carried out for 1.5 h to obtain a dry gel. The gel was taken out, calcined at 900 °C for 3 h, ball-milled for 4 h, and reduced with hydrogen at 670 °C in a strong drainage and permeable tube furnace for 4 h with a hydrogen flow rate of 17 L / min to obtain tungsten-copper-silver alloy coated tourmaline nanospheres.

[0048] S3. Graphene oxide coating: 13 parts by weight of graphene oxide were dissolved in 500 parts by weight of water, and 22 parts by weight of tungsten-copper-silver alloy coated tourmaline nanospheres obtained in step S2 were added. The mixture was stirred by ultrasonication at 1250W for 25 minutes, centrifuged, washed, and dried to obtain graphene oxide / tungsten-copper-silver alloy coated tourmaline nanospheres.

[0049] S4. Reduction: Add 10 parts by weight of the modified nanospheres obtained in step S3 to 200 parts by weight of water, add 4 parts by weight of hydrazine hydrate and 3 parts by weight of 23wt% ammonia water, heat to 85℃, stir and react for 3 hours, centrifuge, wash, and dry to obtain modified nanospheres.

[0050] S5. Preparation of heat dissipation material for electronic packaging: 85 parts by weight of the modified nanospheres obtained in step S4 and 25 parts by weight of copper powder were stirred and mixed for 20 min, ball milled at 170 r / min for 1.5 h, cold pressed at 57 MPa for 1.5 min, and sintered at 2 GPa and 1000℃ for 15 min to obtain the heat dissipation material for electronic packaging.

[0051] Comparative Example 1

[0052] The difference from Example 3 is that copper nitrate was not added in step S2.

[0053] Comparative Example 2

[0054] The difference from Example 3 is that silver nitrate was not added in step S2.

[0055] Comparative Example 3

[0056] The difference from Example 3 is that sodium tungstate was not added in step S2.

[0057] Comparative Example 4

[0058] The difference from Example 3 is that step S2 was not performed.

[0059] Comparative Example 5

[0060] The difference from Example 3 is that steps S3 and S4 were not performed.

[0061] Test Example 1

[0062] The thermal conductivity of the electronic packaging heat dissipation materials prepared in Examples 1-3 and Comparative Examples 1-5 was tested using a laser thermal conductivity meter at a heating rate of 10 K / min, from room temperature to 800 °C. The results are shown in Table 1.

[0063]

[0064] As can be seen from the table above, the heat dissipation materials for electronic packaging prepared in Examples 1-3 of the present invention have good thermal conductivity.

[0065] Test Example 2

[0066] The bending strength of the heat dissipation materials for electronic packaging prepared in Examples 1-3 and Comparative Examples 1-5 was tested, and the results are shown in Table 2.

[0067]

[0068] As can be seen from the table above, the heat dissipation materials for electronic packaging prepared in Examples 1-3 of the present invention have good bending strength.

[0069] Test Example 3

[0070] The heat dissipation performance of the electronic packaging heat dissipation materials prepared in Examples 1-3 and Comparative Examples 1-5 was tested. A comparison was made between conventional molybdenum-copper and diamond / copper heat sinks. The heat sink dimensions were 12mm × 13mm × 1mm. The substrate material was the electronic packaging heat dissipation material prepared in Examples 1-3 or Comparative Examples 1-5, symmetrically placed at two central locations, while a conventional molybdenum-copper sheet was used at the other location. A resistor was used to simulate chip heating. The resistor dimensions were 2.4mm × 4.8mm × 2mm, and the housing material was aluminum-silicon with a gold-plated surface. A cold plate was positioned near the heat source with flow channels. The housing was pressed against the cold plate via a locking mechanism. The resistor's heating power was 30W. An equivalent voltage was applied across the resistor. After the temperature stabilized, the surface temperature of the resistor at two locations was measured using a thermal infrared meter. The results are shown in Table 3.

[0071]

[0072] As can be seen from the table above, the heat dissipation materials for electronic packaging prepared in Examples 1-3 of the present invention have good heat dissipation effects.

[0073] Compared with Example 3, Comparative Examples 1, 2, and 3 did not include copper nitrate, silver nitrate, or sodium tungstate in step S2. Comparative Example 4, compared with Example 3, did not perform step S2. The thermal conductivity and heat dissipation performance of the resulting heat dissipation material for electronic packaging decreased. This invention pulverizes tourmaline, ball-mills it to obtain nanoscale tourmaline ultrafine powder, and uses this ultrafine powder as the core. The surface is then coated with a W-Cu-Ag oxide layer through calcination and low-temperature hydrogen reduction to obtain tungsten-copper-silver alloy-coated tourmaline nanospheres. This tungsten-copper-silver alloy has extremely high thermal conductivity, further improving the heat dissipation performance of the obtained nanospheres. The addition of the tungsten-copper-silver alloy coating has a synergistic effect.

[0074] Compared to Example 3, Comparative Example 5 omitted steps S3 and S4. The resulting heat dissipation material for electronic packaging exhibited decreased thermal conductivity, reduced bending resistance, and decreased heat dissipation performance. In this invention, a layer of graphene oxide is further coated onto the surface of the tungsten-copper-silver alloy-coated tourmaline nanospheres. After reduction with hydrazine hydrate, the modified nanospheres are further coated with a high-thermal-conductivity graphite layer on top of the existing tungsten-copper-silver alloy coating. This further improves the thermal conductivity of the nanospheres and enhances the interfacial bonding of the tungsten-copper-silver alloy, resulting in a tighter bond and improved mechanical and heat dissipation properties of the prepared heat dissipation material.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a heat dissipation material for electronic packaging, characterized in that, Includes the following steps: S1. Processing of tourmaline: Tourmaline is crushed, ball-milled, sieved, washed, and dried to obtain ultrafine tourmaline powder; S2. Tungsten-copper-silver alloy coating: The tourmaline ultrafine powder obtained in step S1 is added to water, sodium tungstate, copper salt and silver salt are added, a complexing agent is added, the mixture is stirred and reacted, the solvent is heated and evaporated to obtain a sol; then the temperature is increased and the vacuum degree is decreased to obtain a dry gel, which is taken out, calcined, ball-milled, and reduced by low-temperature hydrogen to obtain tungsten-copper-silver alloy coated tourmaline nanospheres; S3. Graphene oxide coating: Graphene oxide is dissolved in water, and tungsten-copper-silver alloy coated tourmaline nanospheres obtained in step S2 are added. The mixture is stirred ultrasonically, centrifuged, washed, and dried to obtain graphene oxide / tungsten-copper-silver alloy coated tourmaline nanospheres. S4. Reduction: Add the modified nanospheres obtained in step S3 to water, add hydrazine hydrate and ammonia, heat and stir to react, centrifuge, wash, and dry to obtain modified nanospheres; S5. Preparation of heat dissipation material for electronic packaging: The modified nanospheres and copper powder obtained in step S4 are mixed evenly, ball-milled, cold-pressed, and sintered at high temperature and high pressure at a pressure of 1-3 GPa and a temperature of 900-1100℃ to obtain heat dissipation material for electronic packaging.

2. The preparation method according to claim 1, characterized in that, The ball milling time in step S1 is 2-4 hours, the sieve mesh size is 300-700 nm, and the cleaning is performed by adding ethanol and ultrasonic treatment at 1000-1200W for 20-30 minutes.

3. The preparation method according to claim 1, characterized in that, In step S2, the mass ratio of tourmaline ultrafine powder, sodium tungstate, copper salt, silver salt, and complexing agent is 20-30:7-10:3-5:7-10:40-50. The copper salt is selected from at least one of copper chloride, copper sulfate, and copper nitrate. The silver salt is silver nitrate. The stirring reaction time is 20-30 min. The complexing agent is selected from at least one of citric acid and sodium citrate. The heating temperature is 45-65℃. The temperature is increased to the heater temperature of 130-140℃, and the vacuum degree is reduced to 0.01-0.1 MPa. The ball milling time is 3-5 h. The low-temperature hydrogen reduction is carried out in a high-pressure drainage and permeable tube furnace at 650-700℃ for 3-5 h with hydrogen flow rate of 15-20 L / min. The calcination temperature is 800-1000℃ for 2-4 h.

4. The preparation method according to claim 1, characterized in that, In step S3, the mass ratio of graphene oxide to tungsten-copper-silver alloy-coated tourmaline nanospheres is 12-15:20-25, the power of the ultrasonic stirring reaction is 1000-1500W, and the time is 20-30min.

5. The preparation method according to claim 1, characterized in that, In step S4, the mass ratio of the modified nanospheres, hydrazine hydrate, and ammonia is 10:3-5:2-4, the concentration of the ammonia is 22-25 wt%, the heating and stirring reaction temperature is 80-90℃, and the time is 2-4 h.

6. The preparation method according to claim 1, characterized in that, In step S5, the mass ratio of modified nanospheres to copper powder is 7-10:2-3, the ball milling speed is 150-200 r / min, the time is 1-2 h, the cold pressing pressure is 55-60 MPa, the time is 1-2 min, and the high temperature and high pressure sintering time is 10-20 min.

7. The preparation method according to claim 1, characterized in that, Specifically, the following steps are included: S1. Treatment of tourmaline: The tourmaline is crushed, ball-milled for 2-4 hours, sieved with a mesh size of 300-700 nm, added to ethanol, ultrasonically cleaned for 20-30 minutes at 1000-1200 W, and dried to obtain tourmaline ultrafine powder. S2. Tungsten-copper-silver alloy coating: 20-30 parts by weight of the tourmaline ultrafine powder obtained in step S1 are added to 500 parts by weight of water, 7-10 parts by weight of sodium tungstate, 3-5 parts by weight of copper salt and 7-10 parts by weight of silver salt are added, and 40-50 parts by weight of complexing agent are added. The mixture is stirred and reacted for 20-30 minutes, heated to 45-65℃, and the solvent is evaporated to obtain a sol. Then the temperature is raised to the heater temperature of 130-140℃, the vacuum degree is reduced to 0.01-0.1MPa, and the reaction is carried out for 1-2 hours to obtain a dry gel. The gel is taken out, calcined at 800-1000℃ for 2-4 hours, ball-milled for 3-5 hours, and reduced with hydrogen gas at 650-700℃ in a strong drainage and permeable tube furnace for 3-5 hours with a hydrogen gas flow rate of 15-20 L / min to obtain tungsten-copper-silver alloy coated tourmaline nanospheres. S3. Graphene oxide coating: Dissolve 12-15 parts by weight of graphene oxide in 500 parts by weight of water, add 20-25 parts by weight of tungsten-copper-silver alloy coated tourmaline nanospheres obtained in step S2, stir ultrasonically at 1000-1500W for 20-30 min, centrifuge, wash, and dry to obtain graphene oxide / tungsten-copper-silver alloy coated tourmaline nanospheres; S4. Reduction: Add 10 parts by weight of the modified nanospheres obtained in step S3 to 200 parts by weight of water, add 3-5 parts by weight of hydrazine hydrate and 2-4 parts by weight of 22-25 wt% ammonia water, heat to 80-90℃, stir and react for 2-4 hours, centrifuge, wash, and dry to obtain modified nanospheres. S5. Preparation of heat dissipation material for electronic packaging: 70-100 parts by weight of the modified nanospheres obtained in step S4 and 20-30 parts by weight of copper powder are mixed evenly, ball-milled at 150-200 r / min for 1-2 h, cold-pressed at 55-60 MPa for 1-2 min, and sintered at 1-3 GPa and 900-1100℃ for 10-20 min to obtain the heat dissipation material for electronic packaging.

8. A heat dissipation material for electronic packaging prepared by the method according to any one of claims 1-7.

9. The application of the heat dissipation material for electronic packaging as described in claim 8 in SiP packaging, thick mold packaging, and high heat dissipation packaging technology.

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