Diamond filler for chip heat dissipation and preparation method thereof

Abstract

The invention discloses a diamond filler for chip heat dissipation and a preparation method thereof, and belongs to the technical field of heat conduction fillers, the diamond filler comprises the following raw materials by weight: 90-100 parts of pretreated functional diamond, 4-8 parts of modified carbon nanotubes and 15-25 parts of modified hexagonal boron nitride nanoparticles; the diamond filler for chip heat dissipation is prepared by mixing pretreated functional diamond, modified carbon nanotubes and modified hexagonal boron nitride nanosheets, adding the mixture into N-methyl pyrrolidone, adding 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide, and carrying out a reaction. According to the mode, micro-grinding rounding and dopamine functionalization of the diamond, carbon nano tube modification and hexagonal boron nitride modification have a synergistic gain effect on the filler heat conductivity, composite material heat conductivity and composite material CTE of the prepared diamond filler.

Description

Technical Field

[0001] This invention relates to the field of thermally conductive filler technology, specifically to a diamond filler for chip heat dissipation and its preparation method. Background Technology

[0002] As integrated circuit manufacturing technology enters the post-Moore's Law era, the power density and integration level of chips have experienced explosive growth. The resulting thermal barrier problem has become one of the core bottlenecks restricting their performance, reliability, and lifespan. Traditional packaging materials (such as thermal grease and gel) have low thermal conductivity, making it difficult to meet the high-efficiency heat dissipation requirements of third-generation semiconductor power devices, high-performance CPUs / GPUs, and other scenarios.

[0003] To improve the thermal conductivity of thermal interface materials, the introduction of high thermal conductivity fillers is a key strategy. Existing technologies have made many improvements to thermally conductive fillers. For example, Chinese patent CN121085583A discloses a method for preparing thermally conductive silicon gel for power module chip packaging. By optimizing diamond micropowder filling, surface etching, and particle size compounding, the thermal conductivity of the prepared thermally conductive silicon gel can reach 3.8~4.5 W / (m·K), far exceeding that of ordinary silicon gel. At the same time, surface etching increases the specific surface area of ​​diamond and the interfacial bonding force with silicon gel, reduces interfacial thermal resistance, and forms a more efficient thermal conduction path. Particle size compounding maximizes the filler packing density, reduces air gaps, and constructs a more stable and interconnected thermal conduction network. SiC devices have high power density and fast switching speed, and the chip junction temperature is a key factor restricting performance and reliability. The above-mentioned materials can quickly and uniformly transfer the chip heat to the heat dissipation substrate, significantly reduce the junction temperature and internal temperature gradient of the module, and improve power density and long-term reliability.

[0004] However, it still has the following shortcomings in practical applications:

[0005] 1. Using only diamonds of different particle sizes for compounding results in a single type of filler, making it difficult to construct a multi-dimensional synergistic heat conduction network, and the heat conduction efficiency still needs to be further improved.

[0006] 2. Surface etching only increases roughness and relies on mechanical interlocking. The reduction of interfacial thermal resistance is incomplete and may affect the reliability of long-term thermal cycling.

[0007] Based on this, the present invention designs a diamond filler for chip heat dissipation and its preparation method to solve the above problems. Summary of the Invention

[0008] In view of the above-mentioned shortcomings of the prior art, the present invention provides a diamond filler for chip heat dissipation and its preparation method.

[0009] To achieve the above objectives, the present invention provides the following technical solution:

[0010] A diamond filler for chip heat dissipation comprises the following raw materials in parts by weight: 90-100 parts pretreated functional diamond, 4-8 parts modified carbon nanotubes and 15-25 parts modified hexagonal boron nitride nanotubes.

[0011] The diamond filler for chip heat dissipation is prepared by mixing pretreated functional diamond, modified carbon nanotubes and modified hexagonal boron nitride nanosheets, adding them to N-methylpyrrolidone, and then reacting 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide.

[0012] Round diamonds are obtained by impact micro-pulverization of diamonds through high-pressure inert gas. After the round diamonds are cleaned, dried and treated with ozone, activated round diamonds are obtained. After the activated round diamonds are mixed and stirred with dopamine hydrochloride, pretreated functional diamonds are obtained.

[0013] Carbon nanotubes were first acid-treated, then reacted with anhydrous thionyl chloride and 1,8-octanediamine in sequence. After the reaction was completed, ascorbic acid was added to carry out the reaction. After the reaction was completed, the modified carbon nanotubes were obtained by centrifugation, washing and drying.

[0014] Hexagonal boron nitride powder was first dispersed with urea in an aqueous hydrogen peroxide solution for reaction. After the reaction was completed, it was reacted with bromoacetic acid. After the reaction was completed, the powder was purified by dialysis and freeze-dried to obtain modified hexagonal boron nitride nanosheets.

[0015] To better achieve the objectives of this invention, this invention also provides a method for preparing diamond filler for chip heat dissipation, specifically including the following steps:

[0016] I. Pretreatment of Diamond Raw Materials

[0017] Round diamonds are obtained by impact micro-pulverization of diamonds through high-pressure inert gas. After the round diamonds are cleaned, dried and treated with ozone, activated round diamonds are obtained. The activated round diamonds are then mixed with dopamine hydrochloride to obtain pretreated functional diamonds.

[0018] II. Modification of Carbon Nanotubes

[0019] 90-100 parts of carbon nanotubes were first acid-treated, and then reacted with 1000-1500 parts of anhydrous thionyl chloride and 2000-2500 parts of 1,8-octanediamine. After the reaction was completed, 65-85 parts of ascorbic acid were added for further reaction. After the reaction was completed, the modified carbon nanotubes were obtained by centrifugation, washing and drying.

[0020] III. Modification of Hexagonal Boron Nitride Nanosheets

[0021] 80-100 parts of hexagonal boron nitride powder were first reacted with 10-30 parts of urea in a 5-10% hydrogen peroxide aqueous solution. After the reaction was completed, it was reacted with 80-120 parts of bromoacetic acid. After the reaction was completed, the powder was purified by dialysis and freeze-dried to obtain modified hexagonal boron nitride nanosheets.

[0022] IV. Preparation of Functionalized Diamond Fillers

[0023] 90-100 parts of pretreated functional diamond, 4-8 parts of modified carbon nanotubes and 15-25 parts of modified hexagonal boron nitride nanosheets were mixed and added to N-methylpyrrolidone to make the total solid content 2-5%. The mixture was ultrasonically dispersed and stirred in an ice-water bath. Then, 8-12% of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 2-4% of N-hydroxysuccinimide were added by weight of the total carbon nanotubes and reacted.

[0024] After the reaction is complete, the material is filtered and washed, then heat-treated under argon protection, and then naturally cooled to room temperature to obtain functionalized diamond filler, i.e. diamond filler for chip heat dissipation.

[0025] Furthermore, in the pretreatment of diamond raw materials, the specific parameters in the preparation process of activated rounded diamonds are as follows:

[0026] The inert gas used is argon, nitrogen or helium, with a gas pressure of 80-150 MPa and a gas velocity of 1.5-3.0 Mach. The single treatment time is 3-5 min, and the treatment is repeated 2-3 times. After treatment, the diamond particles with a diameter of 10-50 micrometers are obtained by sieving. The ozone treatment time for the rounded diamonds is 30-60 min.

[0027] Furthermore, in the pretreatment of diamond raw materials, the specific process for preparing pretreated functional diamonds is as follows:

[0028] Disperse 90-100 parts of activated rounded diamond in Tris buffer, add 1-2 parts of dopamine hydrochloride, stir at 100-200 rpm for 5-8 hours at 20-30℃, filter and wash to obtain pretreated functional diamond.

[0029] Furthermore, the specific parameters involved in the modification process of carbon nanotubes are as follows:

[0030] The reaction conditions for carbon nanotubes and anhydrous thionyl chloride are: stirring at 300-400 rpm for 20-28 h at 70-75℃;

[0031] The subsequent reaction conditions with 1,8-octanediamine were: 78-85℃ with stirring at 400-500 rpm for 45-50 h;

[0032] The reaction conditions for adding ascorbic acid are: stirring at 150-250 rpm for 5-8 hours at 55-65℃.

[0033] Furthermore, the specific parameters involved in the modification process of hexagonal boron nitride nanosheets are as follows:

[0034] The reaction conditions for hexagonal boron nitride with urea are: reaction at 150-170℃ for 8-12 hours;

[0035] The subsequent reaction conditions with bromoacetic acid were: stirring at 300-500 rpm for 20-28 hours at 58-65℃.

[0036] Furthermore, the specific parameters involved in the preparation process of functionalized diamond fillers are as follows:

[0037] The ultrasonic treatment was carried out at a power of 300-500W for 30-60 minutes, followed by stirring for 1-3 hours at a pH of 8.3-8.7 and a speed of 200-400rpm.

[0038] The reaction conditions are 95-110℃ for 10-14 hours.

[0039] Furthermore, the specific parameters for the heat treatment are as follows:

[0040] Increase the temperature to 300-400℃ at a rate of 1-3℃ / min, hold for 20-40 minutes, then increase the temperature to 500-600℃ at the same rate and hold for 10-30 minutes.

[0041] To better achieve the objectives of this invention, this invention also provides a diamond filler prepared by the above-described preparation method.

[0042] To better achieve the objectives of this invention, the present invention also provides an application of the above-mentioned diamond filler in thermally conductive materials.

[0043] Compared with the prior art, the beneficial effects of this invention are as follows: 1. This invention uses a combination of multiple materials such as rounded diamond, modified carbon nanotubes and modified hexagonal boron nitride nanosheets, which breaks through the bottleneck of thermal conductivity of a single filler system and significantly improves the thermal conductivity of the composite material.

[0044] 2. Functional modification of diamond, carbon nanotubes and hexagonal boron nitride nanosheets reduces interfacial thermal resistance and improves the thermal expansion coefficient of the subsequent composite material, thereby ensuring the long-term thermal cycling reliability of the composite material.

[0045] 3. The micronization and rounding of diamond, dopamine functionalization, carbon nanotube modification, and hexagonal boron nitride modification have a synergistic effect on the thermal conductivity of the prepared diamond filler, the thermal conductivity of the composite material, and the CTE of the composite material. Attached Figure Description

[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0047] Figure 1 Electron microscopy of the un-micronized diamond raw material in this invention. Figure 1 ;

[0048] Figure 2 Electron microscopy of the un-micronized diamond raw material in this invention. Figure 2 ;

[0049] Figure 3 Electron microscopy of the rounded diamond that has undergone micronization in this invention. Figure 1 ;

[0050] Figure 4 Electron microscopy of the rounded diamond that has undergone micronization in this invention. Figure 2 ;

[0051] Figure 5 This is a process flow diagram of the present invention. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0053] Example 1: A method for preparing diamond filler for chip heat dissipation, the process flow is as follows: Figure 5 As shown, the specific steps include:

[0054] I. Pretreatment of Diamond Raw Materials

[0055] Diamond raw materials were subjected to impact micro-pulverization using high-pressure inert gas. The inert gas used was argon, with a gas pressure of 80 MPa and a gas velocity of Mach 3. The single treatment time was 3 minutes, and the treatment was repeated 3 times. After treatment, the diamonds were sieved to obtain round diamonds.

[0056] Unprocessed diamond raw materials, such as Figure 1 and Figure 2 As shown, a perfectly round diamond... Figure 3 and Figure 4 As shown.

[0057] The rounded diamond was soaked and cleaned successively with aqua regia and hydrofluoric acid, then washed with deionized water until neutral, vacuum dried, and then treated with ozone for 30 minutes to obtain activated rounded diamond.

[0058] 90 parts of activated rounded diamond were dispersed in Tris buffer, 2 parts of dopamine hydrochloride were added, and the mixture was stirred at 200 rpm for 5 h at 20 °C. After filtration and washing, pretreated functional diamond was obtained.

[0059] II. Modification of Carbon Nanotubes

[0060] Ninety parts of carbon nanotubes treated with concentrated nitric acid and concentrated sulfuric acid were added to 1500 parts of anhydrous thionyl chloride and stirred at 400 rpm at 70°C for 20 h. After centrifugation, 2500 parts of 1,8-octanediamine were added and stirred at 500 rpm at 78°C for 45 h. Then, 85 parts of ascorbic acid were added and stirred at 250 rpm at 55°C for 5 h. After the reaction was completed, the modified carbon nanotubes were obtained by centrifugation, washing and drying.

[0061] III. Modification of Hexagonal Boron Nitride Nanosheets

[0062] 80 parts of hexagonal boron nitride powder and 30 parts of urea were dispersed in a 5% hydrogen peroxide aqueous solution and reacted at 170℃ for 8 hours. After centrifugation and washing, the mixture was resuspended in a sodium hydroxide aqueous solution. 120 parts of bromoacetic acid were added, and the mixture was stirred at 500 rpm at 58℃ for 20 hours. After the reaction was completed, the mixture was purified by dialysis and freeze-dried to obtain modified hexagonal boron nitride nanosheets.

[0063] IV. Preparation of Functionalized Diamond Fillers

[0064] 90 parts of pretreated functional diamond, 8 parts of modified carbon nanotubes and 15 parts of modified hexagonal boron nitride nanosheets were mixed and added to N-methylpyrrolidone to make the total solid content 5%. The mixture was ultrasonically dispersed for 60 minutes at 300W in an ice-water bath using a cell disruption sonicator. Then, the mixture was stirred for 1 hour at pH 8.3 and a rotation speed of 400 rpm. Subsequently, 12% of the total weight of carbon nanotubes in 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC·HCl) and 2% of the total weight of boron nitride nanosheets in N-hydroxysuccinimide were added, and the mixture was reacted at 110℃ for 10 hours.

[0065] After the reaction is complete, the mixture is filtered and washed, and then heat-treated under argon protection: the temperature is increased to 400℃ at a rate of 1℃ / min and held for 20 minutes, then increased to 600℃ at the same rate and held for 10 minutes, and then naturally cooled to room temperature to obtain functionalized diamond filler, i.e. diamond filler for chip heat dissipation.

[0066] Example 2: A method for preparing diamond filler for chip heat dissipation, specifically including the following steps:

[0067] I. Pretreatment of Diamond Raw Materials

[0068] Diamond raw materials were subjected to impact micro-pulverization using high-pressure inert gas. The inert gas used was nitrogen, with a gas pressure of 150 MPa and a gas velocity of Mach 1.5. The single treatment time was 5 minutes, and the treatment was repeated twice. After treatment, the diamonds were sieved to obtain round diamonds.

[0069] The rounded diamond was soaked and cleaned successively with aqua regia and hydrofluoric acid, then washed with deionized water until neutral, vacuum dried, and then treated with ozone for 60 minutes to obtain activated rounded diamond.

[0070] 100 parts of activated rounded diamond were dispersed in Tris buffer, 1 part of dopamine hydrochloride was added, and the mixture was stirred at 100 rpm for 8 hours at 30°C. After filtration and washing, pretreated functional diamond was obtained.

[0071] II. Modification of Carbon Nanotubes

[0072] 100 parts of carbon nanotubes treated with concentrated nitric acid and concentrated sulfuric acid were added to 1000 parts of anhydrous thionyl chloride and stirred at 300 rpm at 75°C for 28 h. After centrifugation, 2000 parts of 1,8-octanediamine were added and stirred at 400 rpm at 85°C for 50 h. Then, 65 parts of ascorbic acid were added and stirred at 150 rpm at 65°C for 8 h. After the reaction was completed, the modified carbon nanotubes were obtained by centrifugation, washing and drying.

[0073] III. Modification of Hexagonal Boron Nitride Nanosheets

[0074] 100 parts of hexagonal boron nitride powder and 10 parts of urea were dispersed in a 10% hydrogen peroxide aqueous solution and reacted at 150°C for 12 h. After centrifugation and washing, the mixture was resuspended in a sodium hydroxide aqueous solution. 80 parts of bromoacetic acid were added, and the mixture was stirred at 300 rpm at 65°C for 28 h. After the reaction was completed, the mixture was purified by dialysis and freeze-dried to obtain modified hexagonal boron nitride nanosheets.

[0075] IV. Preparation of Functionalized Diamond Fillers

[0076] 100 parts of pretreated functional diamond, 4 parts of modified carbon nanotubes and 25 parts of modified hexagonal boron nitride nanosheets were mixed and added to N-methylpyrrolidone to make the total solid content 2%. The mixture was ultrasonically dispersed for 30 minutes at 500W in an ice-water bath using a cell disruption sonicator. Then, the mixture was stirred for 3 hours at pH 8.7 and a rotation speed of 200 rpm. Subsequently, 8% of the total weight of carbon nanotubes in EDC·HCl and 4% of the total weight of boron nitride nanosheets in N-hydroxysuccinimide were added, and the mixture was reacted at 95℃ for 14 hours.

[0077] After the reaction is complete, the mixture is filtered and washed, and then heat-treated under argon protection: the temperature is increased to 300℃ at a rate of 3℃ / min and held for 40 minutes, then increased to 500℃ at the same rate and held for 30 minutes, and then naturally cooled to room temperature to obtain functionalized diamond filler, i.e. diamond filler for chip heat dissipation.

[0078] Example 3: A method for preparing diamond filler for chip heat dissipation, specifically including the following steps:

[0079] I. Pretreatment of Diamond Raw Materials

[0080] Diamond raw materials were subjected to impact micro-pulverization using high-pressure inert gas. The inert gas used was helium, with a pressure of 120 MPa and a velocity of Mach 2. The single treatment time was 4 minutes, and the treatment was repeated 3 times. After treatment, the diamonds were sieved to obtain round diamonds.

[0081] The rounded diamond was soaked and cleaned successively with aqua regia and hydrofluoric acid, then washed with deionized water until neutral, vacuum dried, and then treated with ozone for 48 minutes to obtain activated rounded diamond.

[0082] 92 parts of activated rounded diamond were dispersed in Tris buffer, 1.5 parts of dopamine hydrochloride were added, and the mixture was stirred at 150 rpm for 6.5 h at 28 °C. After filtration and washing, pretreated functional diamond was obtained.

[0083] II. Modification of Carbon Nanotubes

[0084] 95 parts of carbon nanotubes treated with concentrated nitric acid and concentrated sulfuric acid were added to 1200 parts of anhydrous thionyl chloride and stirred at 325 rpm at 73°C for 25 h. After centrifugation, 2150 parts of 1,8-octanediamine were added and stirred at 450 rpm at 80°C for 48 h. Then, 70 parts of ascorbic acid were added and stirred at 180 rpm at 60°C for 6 h. After the reaction was completed, the modified carbon nanotubes were obtained by centrifugation, washing and drying.

[0085] III. Modification of Hexagonal Boron Nitride Nanosheets

[0086] 90 parts of hexagonal boron nitride powder and 22 parts of urea were dispersed in a 7.5% aqueous solution of hydrogen peroxide and reacted at 160°C for 10 h. After centrifugation and washing, the mixture was resuspended in an aqueous solution of sodium hydroxide. 105 parts of bromoacetic acid were added, and the mixture was stirred at 375 rpm at 61°C for 25 h. After the reaction was completed, the mixture was purified by dialysis and freeze-dried to obtain modified hexagonal boron nitride nanosheets.

[0087] IV. Preparation of Functionalized Diamond Fillers

[0088] 93 parts of pretreated functional diamond, 7 parts of modified carbon nanotubes and 20 parts of modified hexagonal boron nitride nanosheets were mixed and added to N-methylpyrrolidone to make the total solid content 3.5%. The mixture was ultrasonically dispersed for 45 minutes at 400W in an ice-water bath using a cell disruption sonicator. Then, the mixture was stirred for 2.5 hours at pH 8.5 and a rotation speed of 250 rpm. Subsequently, 10% of the total weight of carbon nanotubes in EDC·HCl and 3% of the total weight of boron nitride nanosheets in N-hydroxysuccinimide were added, and the mixture was reacted at 100℃ for 12 hours.

[0089] After the reaction is complete, the mixture is filtered and washed, and then heat-treated under argon protection: the temperature is increased to 350°C at a rate of 2°C / min and held for 30 minutes, then increased to 530°C at the same rate and held for 20 minutes, and then naturally cooled to room temperature to obtain functionalized diamond filler, i.e. diamond filler for chip heat dissipation.

[0090] Comparative Example 1: Compared with Example 3, the diamond raw material pretreatment did not involve micronization, rounding, or dopamine functionalization.

[0091] Ninety-two portions of diamond raw materials were directly soaked, washed, dried, and ozone treated sequentially. After ozone treatment, no stirring reaction with dopamine hydrochloride in Tris buffer was performed to obtain pretreated functional diamonds. The remaining steps were the same as in Example 3.

[0092] Comparative Example 2: Compared with Example 3, ascorbic acid was not added for stirring during the modification of carbon nanotubes, and the remaining steps were the same as in Example 3.

[0093] Comparative Example 3: Compared with Example 3, no urea-assisted hydrogen peroxide exfoliation and bromoacetic acid carboxylation modification were performed during the modification of hexagonal boron nitride nanosheets.

[0094] 90 parts of hexagonal boron nitride powder were dispersed in a 7.5% hydrogen peroxide aqueous solution and stirred at 300 rpm for 10 h at 160 °C. After centrifugation and washing, the mixture was resuspended in a sodium hydroxide aqueous solution. 105 parts of bromoacetic acid were added, and the mixture was stirred at 375 rpm for 25 h at 61 °C. After the reaction was completed, the mixture was purified by dialysis and freeze-dried to obtain modified hexagonal boron nitride nanosheets.

[0095] The remaining steps are the same as in Example 3.

[0096] Comparative Example 4: Compared with Example 3, the diamond raw material was not subjected to micro-pulverization and rounding treatment or dopamine functionalization treatment. Ascorbic acid was not added for stirring reaction during the modification of carbon nanotubes. Urea was not added to assist in the modification of hexagonal boron nitride nanosheets. The remaining steps were the same as in Example 3.

[0097] Experimental Example: The following performance tests were performed on Examples 1-3 and Comparative Examples 1-4:

[0098] Filler thermal conductivity: The diamond fillers prepared in Examples 1-3 and Comparative Examples 1-4 were cold-pressed into sheets, and their in-plane thermal diffusivity was measured and the thermal conductivity was calculated using the laser flare method.

[0099] Thermal conductivity of composite materials: The filler was uniformly dispersed in the epoxy resin matrix at a filling rate of 60%, and the thermal conductivity of the composite material in the vertical direction was tested after curing.

[0100] Coefficient of thermal expansion (CTE) of composite materials: This measures the coefficient of thermal expansion of the composite materials mentioned above. It indirectly reflects the interfacial bonding strength between the filler and the polymer matrix; the better the bonding, the lower the CTE.

[0101] Composite material resistivity: The volume resistivity of the above composite material was tested.

[0102] Table 1 Performance test results of Examples 1-3 and Comparative Examples 1-4

[0103]

[0104] As shown in Examples 1-3, the diamond filler for chip heat dissipation prepared using the method of this invention has a filler thermal conductivity of 238-252 W / m·K. The epoxy resin composite material prepared using this filler exhibits excellent comprehensive performance: a thermal conductivity of 11.9-12.3 W / m·K, a low coefficient of thermal expansion of 30-35 ppm / K, and extremely high insulation resistivity. These data indicate that the filler not only has excellent thermal conductivity itself but also plays a role in efficient thermal conduction, low thermal stress, and electrical insulation within the polymer matrix. The filler and composite material in Example 3 exhibit the best comprehensive performance across all indicators.

[0105] As can be seen from Example 3 and Comparative Example 1, if the diamond is not subjected to high-pressure gas micro-pulverization and rounding and dopamine functionalization, the thermal conductivity of the prepared filler and the thermal conductivity of the composite material both decrease, while the CTE of the composite material increases significantly.

[0106] As can be seen from Example 3 and Comparative Example 2, if the amylation grafting step is omitted in the modification of carbon nanotubes, the resistivity of the composite material prepared by the filler decreases sharply, and the thermal conductivity of the composite material also decreases.

[0107] As can be seen from Example 3 and Comparative Example 3, if the carboxylation modification of hexagonal boron nitride is not performed, the thermal conductivity of the composite material of the prepared filler decreases and the CTE increases.

[0108] As can be seen from Example 3 and Comparative Example 4, the micro-pulverization and rounding of diamond, dopamine functionalization, carbon nanotube modification and hexagonal boron nitride modification have a synergistic effect on the filler thermal conductivity, composite thermal conductivity and composite CTE of the prepared diamond filler.

[0109] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A diamond filler for chip heat dissipation, characterized in that, The raw materials include the following parts by weight: 90-100 parts pretreated functional diamond, 4-8 parts modified carbon nanotubes and 15-25 parts modified hexagonal boron nitride nanotubes; The diamond filler for chip heat dissipation is prepared by mixing pretreated functional diamond, modified carbon nanotubes and modified hexagonal boron nitride nanosheets, adding them to N-methylpyrrolidone, and then reacting 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide. Round diamonds are obtained by impact micro-pulverization of diamonds through high-pressure inert gas. After the round diamonds are cleaned, dried and treated with ozone, activated round diamonds are obtained. After the activated round diamonds are mixed and stirred with dopamine hydrochloride, pretreated functional diamonds are obtained. Carbon nanotubes were first acid-treated, then reacted with anhydrous thionyl chloride and 1,8-octanediamine in sequence. After the reaction was completed, ascorbic acid was added to carry out the reaction. After the reaction was completed, the modified carbon nanotubes were obtained by centrifugation, washing and drying. Hexagonal boron nitride powder was first dispersed with urea in an aqueous hydrogen peroxide solution for reaction. After the reaction was completed, it was reacted with bromoacetic acid. After the reaction was completed, the powder was purified by dialysis and freeze-dried to obtain modified hexagonal boron nitride nanosheets.

2. A method for preparing diamond filler for chip heat dissipation according to claim 1, characterized in that, Specifically, the following steps are included: I. Pretreatment of Diamond Raw Materials Round diamonds are obtained by impact micro-pulverization of diamonds through high-pressure inert gas. After cleaning, drying and ozone treatment of the round diamonds, activated round diamonds are obtained. After mixing and stirring the activated round diamonds with dopamine hydrochloride, pretreated functional diamonds are obtained. II. Modification of Carbon Nanotubes 90-100 parts of carbon nanotubes were first acid-treated, and then reacted with 1000-1500 parts of anhydrous thionyl chloride and 2000-2500 parts of 1,8-octanediamine. After the reaction was completed, 65-85 parts of ascorbic acid were added for further reaction. After the reaction was completed, the modified carbon nanotubes were obtained by centrifugation, washing and drying. III. Modification of Hexagonal Boron Nitride Nanosheets 80-100 parts of hexagonal boron nitride powder were first dispersed with 10-30 parts of urea in a 5-10% hydrogen peroxide aqueous solution for reaction. After the reaction was completed, it was reacted with 80-120 parts of bromoacetic acid. After the reaction was completed, the powder was purified by dialysis and freeze-dried to obtain modified hexagonal boron nitride nanosheets. IV. Preparation of Functionalized Diamond Fillers 90-100 parts of pretreated functional diamond, 4-8 parts of modified carbon nanotubes and 15-25 parts of modified hexagonal boron nitride nanosheets were mixed and added to N-methylpyrrolidone to make the total solid content 2-5%. The mixture was ultrasonically dispersed and stirred in an ice-water bath. Then, 8-12% of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 2-4% of N-hydroxysuccinimide were added by weight of the total carbon nanotubes and reacted. After the reaction is complete, the material is filtered and washed, then heat-treated under argon protection, and subsequently cooled naturally to room temperature to obtain functionalized diamond filler, i.e., diamond filler for chip heat dissipation.

3. The method for preparing diamond filler for chip heat dissipation according to claim 2, characterized in that, In the pretreatment of diamond raw materials, the specific parameters in the preparation process of activated rounded diamonds are as follows: The inert gas used is argon, nitrogen or helium, with a gas pressure of 80-150 MPa and a gas velocity of 1.5-3.0 Mach. The single treatment time is 3-5 min, and the treatment is repeated 2-3 times. After treatment, the diamond particles with a diameter of 10-50 micrometers are obtained by sieving. The ozone treatment time for the rounded diamonds is 30-60 min.

4. The method for preparing diamond filler for chip heat dissipation according to claim 2, characterized in that, In the pretreatment of diamond raw materials, the specific process for preparing pretreated functional diamonds is as follows: Disperse 90-100 parts of activated rounded diamond in Tris buffer, add 1-2 parts of dopamine hydrochloride, stir at 100-200 rpm for 5-8 hours at 20-30℃, filter and wash to obtain pretreated functional diamond.

5. The method for preparing diamond filler for chip heat dissipation according to claim 2, characterized in that, The specific parameters involved in the modification process of carbon nanotubes are as follows: The reaction conditions for carbon nanotubes and anhydrous thionyl chloride are: stirring at 300-400 rpm for 20-28 h at 70-75℃; The subsequent reaction conditions with 1,8-octanediamine were: 78-85℃ with stirring at 400-500 rpm for 45-50 h; The reaction conditions for adding ascorbic acid are: stirring at 150-250 rpm for 5-8 hours at 55-65℃.

6. The method for preparing diamond filler for chip heat dissipation according to claim 2, characterized in that, The specific parameters involved in the modification process of hexagonal boron nitride nanosheets are as follows: The reaction conditions for hexagonal boron nitride with urea are: reaction at 150-170℃ for 8-12 hours; The subsequent reaction conditions with bromoacetic acid were: stirring at 300-500 rpm for 20-28 hours at 58-65℃.

7. The method for preparing diamond filler for chip heat dissipation according to claim 2, characterized in that, The specific parameters involved in the preparation of functionalized diamond fillers are as follows: The ultrasonic treatment was carried out at a power of 300-500W for 30-60 minutes, followed by stirring for 1-3 hours at a pH of 8.3-8.7 and a speed of 200-400rpm. The reaction conditions are 95-110℃ for 10-14 hours.

8. The method for preparing diamond filler for chip heat dissipation according to claim 2, characterized in that, The specific parameters for heat treatment are as follows: Increase the temperature to 300-400℃ at a rate of 1-3℃ / min, hold for 20-40 minutes, then increase the temperature to 500-600℃ at the same rate and hold for 10-30 minutes.

9. A diamond filler prepared by the preparation method according to any one of claims 2-8.

10. The application of the diamond filler according to claim 9 in a thermally conductive material.

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