A conformal thermally conductive insulating composite material and methods of making and applying the same

Abstract

The application discloses a kind of conformal heat-conducting insulating composite material and its preparation method and application method, it is related to semiconductor packaging and thermal management technical field.The composite material includes: organic polysilazane resin 40-60 parts, toughening agent 4-10 parts, crosslinking agent 0.1-3 parts, low dielectric heat-conducting filler 35-85 parts, heat-conducting filler dispersant 0.3-2 parts, low volume shrinkage modifier 5-10 parts, catalyst 0.1-1 part, polymerization inhibitor 0.01-0.06 parts, solvent 5-90 parts;Wherein low dielectric heat-conducting filler is hexagonal boron nitride nanosheet, spherical silicon powder and the complex of undefined aluminum nitride, low volume shrinkage modifier is cage-type silsesquioxane.The composite material of the application can perfectly fill micron chip gap, volume shrinkage rate is low after solidification, interface thermal resistance is small, has excellent temperature resistance and high insulation, can satisfy the requirement of high-end equipment manufacturing field such as aerospace, high-performance computing to thermal management material.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging and thermal management technology, and in particular to a conformal thermally conductive and insulating composite material based on a polysilazane precursor for use in the internal stacking gaps of three-dimensional integrated circuits, as well as its preparation and application methods. Background Technology

[0002] With the development of 3D integrated circuits, the vertical stacking of multiple chips has led to a sharp increase in internal heat flux density and serious heat accumulation problems. The gaps between stacked chips are small and irregular in shape. Traditional thermal interface materials such as thermal pads and silicone grease are difficult to effectively fill and maintain low thermal resistance due to insufficient fluidity, filling properties and long-term stability.

[0003] In existing solutions, while non-conductive adhesives / underfill adhesives offer some stress buffering and heat conduction, even those filled with fillers like alumina typically have low effective thermal conductivity, becoming a major thermal bottleneck. Furthermore, thermally conductive adhesive films, which are solid dry films filled with highly thermally conductive fillers and pressed between chips via thermoforming, suffer from less perfect microscopic contact between the dry film and chip surface compared to liquid materials, resulting in higher interfacial thermal resistance. While superior to ordinary underfill adhesives, they remain insufficient for future ultra-high power consumption chips. Although metal-based interface materials offer excellent thermal conductivity, their electrical conductivity necessitates complex insulation designs, increasing manufacturing difficulty and cost.

[0004] Existing reports indicate that acrylic resins, polyurethanes, epoxy resins, and silicone resins are suitable matrix materials for thermally conductive coatings. However, the long-term heat resistance of these matrix materials is generally below 150℃ or they have poor interfacial adhesion. Polysilazane, as a ceramic precursor, has the characteristics of low-temperature curing, excellent heat resistance, and good thermal conductivity and insulation potential. However, its direct application faces bottlenecks: firstly, the thermal conductivity of pure polysilazane is limited after curing; secondly, the large volume shrinkage during curing / ceramization easily leads to interfacial separation or self-cracking, which increases thermal resistance; and thirdly, the cured material is relatively hard and lacks flexibility, resulting in poor adhesion as a thermal interface material.

[0005] In particular, in high-end equipment manufacturing fields that require zero failures, ultra-long lifespans, and tolerance to extreme environments, such as aerospace, military equipment, high-performance computing, and autonomous driving, the chip junction temperature will inevitably rise in the pursuit of higher computing power and higher density. Therefore, there is an urgent need to develop an in-situ molded conformal thermally conductive and insulating composite material based on polysilazane precursors, which features ultra-low interface thermal resistance, good process adaptability, high insulation and low dielectric constant, to meet the more reliable safety margin of current and future generations of high-performance multi-chip vertical stacking. Summary of the Invention

[0006] To address the problems existing in the prior art, the present invention aims to provide a conformal thermally conductive and insulating composite material, its preparation method, and its application method. This conformal thermally conductive and insulating composite material has excellent conformal filling and low interfacial thermal resistance performance, can achieve a balance between high thermal conductivity and low shrinkage, and has good thermal expansion matching with silicon-based chips, and can perfectly fill the irregular micro gaps in three-dimensional chips.

[0007] This invention provides the following technical solution:

[0008] In a first aspect, the present invention provides a conformal thermally conductive and insulating composite material, comprising the following components by mass parts:

[0009] Organopolysilazane resin: 40-60 parts;

[0010] Toughening agent: 4-10 parts;

[0011] Crosslinking agent: 0.1-3 parts;

[0012] Low dielectric thermally conductive filler: 35-85 parts, wherein the low dielectric thermally conductive filler is a compound of hexagonal boron nitride nanosheets, spherical silicon micro powder and amorphous aluminum nitride;

[0013] Thermally conductive filler dispersant: 0.3-2 parts;

[0014] Low volume shrinkage modifier: 5-10 parts, wherein the low volume shrinkage modifier is a cage-type silsesquioxane;

[0015] Catalyst: 0.1-1 part;

[0016] Polymerization inhibitor: 0.01-0.06 parts;

[0017] Solvent: 5-90 parts.

[0018] Furthermore, the low-dielectric thermally conductive filler is a composite of hexagonal boron nitride nanosheets, spherical silicon micropowder, and amorphous aluminum nitride, wherein the medium particle size of the hexagonal boron nitride nanosheets is 0.2-3 micrometers, the medium particle size of the spherical silicon micropowder is 1-3 micrometers, and the medium particle size of the amorphous aluminum nitride is 0.1-2 micrometers.

[0019] Preferably, the mass ratio of the hexagonal boron nitride nanosheets, spherical silicon micropowder, and amorphous aluminum nitride is 10:(1-3):(1-6).

[0020] Furthermore, the organopolysilazane resin is one or a combination of two of methylhydropolysilazane, vinylhydropolysilazane, or vinylpolysilazane, with a viscosity of 20-20000 cp, a hydrogen content of 0-0.9%, and a vinyl content of 0-1.8%.

[0021] Furthermore, the toughening agent is methylphenyl vinyl silicone resin, wherein the vinyl content is 1.2-1.4%, the phenyl content is 5-30%, and the viscosity is 3000-200000 cs.

[0022] Furthermore, the crosslinking agent is a methyl hydrogen-containing silicone resin, wherein the hydrogen content is 0.2-0.8% and the viscosity is 20-300 cs.

[0023] Furthermore, the cage-like silsesquioxane is selected from one of dimethylsiloxy cage-like polysilsesquioxane and octavinyl cage-like polysilsesquioxane.

[0024] Furthermore, the thermally conductive filler dispersant is selected from one of octyltriethoxysilane, decyltriethoxysilane, BYK-2150 (trade name), and 3-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0025] Furthermore, the catalyst is a 500-5000 ppm castor platinum catalyst.

[0026] Furthermore, the polymerization inhibitor is selected from one of diethyl maleate, dimethyl sulfide, 2-methyl-3-butyn-2-ol, and 1-ethynyl-1-cyclohexanol.

[0027] Furthermore, the solvent is used to adjust the viscosity.

[0028] Preferably, the solvent is selected from xylene, hexamethyldisiloxane, n-hexane, cyclohexane, n-heptane, and acetone.

[0029] Preferably, the viscosity of the conformal thermally conductive and insulating composite material is between 400 and 25000 mPa·s.

[0030] Secondly, the present invention also provides a method for preparing the above-mentioned conformal thermally conductive and insulating composite material, comprising the following steps:

[0031] S1. Mix the low dielectric thermally conductive filler and the thermally conductive filler dispersant, and disperse them at 500-2500 rpm for 3-19 minutes at 60-80℃ to improve the dispersibility between the low dielectric thermally conductive fillers, reduce agglomeration, and increase the filling amount of the low dielectric thermally conductive filler in the organic matter, so as to achieve high thermal conductivity and reduce thermal resistance.

[0032] S2. Heat the mixture obtained in step S1 to 100-120℃ and dehydrate and dry it at a speed of 50-150 rpm for 30-90 minutes.

[0033] S3. The material dried in step S2 is sieved to remove large-diameter particles and obtain the processed thermally conductive filler.

[0034] S4. Mix the organopolysilazane resin, toughening agent, crosslinking agent, low volume shrinkage modifier and polymerization inhibitor, and disperse them under vacuum at a speed of 20-60 rpm for 5-15 minutes.

[0035] S5. Add the thermally conductive filler treated in step S3 to the mixture in step S4 in two batches, and disperse it under vacuum conditions at a speed of 400-800 rpm for 30-90 minutes each time.

[0036] S6. Add the catalyst and solvent to the mixture obtained in step S5, and disperse it under vacuum at a speed of 20-60 rpm for 4-8 minutes to obtain the conformal thermally conductive and insulating composite material.

[0037] Preferably, in steps S4 and S5, the vacuum degree of the vacuum condition is less than -0.08 MPa.

[0038] Preferably, in step S3, the sieving is performed using a vibrating screen with a mesh size of 1200-1500.

[0039] Thirdly, the method for applying the conformal thermally conductive and insulating composite material in three-dimensional integrated circuits includes the following steps:

[0040] A1. Inject or coat the conformal thermally conductive and insulating composite material into the gaps between stacked chips of a three-dimensional integrated circuit;

[0041] A2. Heat at 50-70℃ for 10-50 minutes to remove the solvent;

[0042] A3. Pre-curing at 80-100℃ for 1-3 hours;

[0043] A4. Finally, perform final heat curing at 150-180℃ under nitrogen protection for 1-5 hours to form a solid composite material interface layer.

[0044] Preferably, the conformal thermally conductive and insulating composite material is injected or coated into the gaps between chips using precision dispensing or inkjet printing techniques.

[0045] The present invention has the following technical effects:

[0046] This invention achieves a balance between low thermal resistance, low shrinkage, and high reliability through the synergistic effect of multiple components, including organopolysilazane resin, toughening agent, crosslinking agent, low dielectric thermal conductivity filler, and low volume shrinkage modifier. The resulting conformal thermally conductive and insulating composite material has adjustable flowability and can perfectly fill micron-level gaps of arbitrary shapes in three-dimensional chip stacks through capillary action. After curing, it forms an atomically close contact with the chip surface, significantly reducing interfacial thermal resistance.

[0047] By constructing a highly efficient three-dimensional thermally conductive network composed of hexagonal boron nitride nanosheets, spherical silica powder, and amorphous aluminum nitride within the matrix, the thermal conductivity of the material is significantly enhanced. Simultaneously, the rigid cage-like structure of the cage-like silsesquioxane effectively suppresses the volume shrinkage of the polysilazane during curing, preventing material cracking and interfacial delamination. Toughening agents are used to improve the brittleness of pure polysilazane, giving the material both excellent flexibility and heat resistance.

[0048] Furthermore, the organic polysilazane resin and the low-dielectric thermally conductive filler are firmly bonded together, exhibiting no oil seepage, cracking, or performance degradation during long-term use. This significantly improves the long-term temperature resistance of the thermal interface material and increases the reliability and safety margin. All components are insulators, and the filler is uniformly dispersed without conductive pathways. Combined with the dense cross-linked network formed after the polysilazane cures, the material possesses excellent high breakdown voltage and electrical insulation properties, fully meeting the insulation requirements between chips.

[0049] This material has a low curing temperature, is compatible with back-end packaging processes, and has a thermal expansion coefficient that matches that of silicon chips. It can maintain structural and performance stability even after wide-temperature cycling and long-term high-temperature aging, and can perfectly meet the stringent requirements of aerospace, high-performance computing and other high-end equipment manufacturing fields for extreme environmental adaptability, ultra-long life and high reliability. Detailed Implementation

[0050] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. 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.

[0051] It should be understood that, when used in this specification and the appended claims, the terms “comprising” and “including” indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0052] Example 1

[0053] A conformal thermally conductive and insulating composite material, comprising the following components by mass parts:

[0054] Organopolysilazane resin: 50 parts, which is vinyl hydrogen polysilazane with a viscosity of 11000cp, a hydrogen content of 0.45%, a vinyl content of 0.9%, and hydrogen groups and vinyl groups are distributed in the side chains of the main chain;

[0055] Toughening agent: 7 parts, which is methylphenyl vinyl silicone resin, wherein the vinyl content is 1.3%, the phenyl content is 18%, and the viscosity is 90000 cs;

[0056] Crosslinking agent: 1.9 parts, which is methyl hydrogen-containing silicone resin (CAS No. 68988-57-8), with a hydrogen content of 0.6% and a viscosity of 160 cs;

[0057] Low dielectric thermally conductive filler: 60 parts, which is a compound of hexagonal boron nitride nanosheets with a medium particle size of 1.5 micrometers, spherical silicon micropowder with a medium particle size of 3 micrometers, and amorphous aluminum nitride with a medium particle size of 0.1 micrometers, wherein the mass ratio of hexagonal boron nitride nanosheets to spherical silicon micropowder and amorphous aluminum nitride is 10:3:1;

[0058] Thermally conductive filler dispersant: 1.1 parts, decyltriethoxysilane;

[0059] Low volume shrinkage modifier: 8 parts, a cage-like silsesquioxane, specifically a dimethylsiloxy cage-like polysilsesquioxane (Ecotion). ® POSS1015);

[0060] Catalyst: 0.5 parts, 3000 ppm Castrol platinum catalyst;

[0061] Polymerization inhibitor: 0.04 parts, which is diethyl maleate;

[0062] Solvent: 90 parts, hexamethyldisiloxane, used to adjust the viscosity to 400 mPa·s.

[0063] The preparation method of the above-mentioned conformal thermally conductive and insulating composite material includes the following steps:

[0064] S1. Add the low dielectric thermally conductive filler and thermally conductive filler dispersant into a high-speed disperser according to the ratio, and disperse them at 70°C and a dispersion speed of 1500 rpm for 11 minutes.

[0065] S2. After the previous dispersion process, reduce the speed of the high-speed disperser to 100 rpm and increase the temperature to 110°C for dehydration and drying for 60 minutes.

[0066] S3. Place the dried thermally conductive filler from the previous step onto a vibrating screen to remove large-diameter filler particles. The mesh size of the vibrating screen is 1350 mesh.

[0067] S4. Add the organopolysilazane resin, toughening agent, crosslinking agent, low volume shrinkage modifier, and polymerization inhibitor into a planetary mixer according to the specified ratio, and disperse them at a low speed of 40 rpm for 10 minutes under a vacuum of less than -0.08 MPa.

[0068] S5. The thermally conductive filler prepared in step S3 is added to the planetary mixer in two batches for high-speed vacuum dispersion. Each batch is stirred and dispersed for 60 minutes at a speed of 600 rpm and a vacuum degree of less than -0.08 MPa.

[0069] S6. Add the catalyst and solvent to the mixture obtained in step S5 according to the specified ratio, and disperse them uniformly under vacuum conditions of less than -0.08MPa at a low speed of 40rpm to obtain a conformal thermally conductive and insulating composite material; in this embodiment, the dispersion time is 6 minutes.

[0070] Example 2

[0071] This embodiment provides a conformal thermally conductive and insulating composite material, which comprises the following components by mass parts:

[0072] Organopolysilazane resin: 60 parts, which is a vinyl polysilazane with a viscosity of 20,000 cp and a vinyl content of 1.8%;

[0073] Toughening agent: 10 parts, which is methylphenyl vinyl silicone resin, wherein the vinyl content is 1.2%, the phenyl content is 30%, and the viscosity is 200,000 cs;

[0074] Crosslinking agent: 3 parts, which is methyl hydrogen-containing silicone resin (CAS No. 68988-57-8), with a hydrogen content of 0.8% and a viscosity of 300 cs;

[0075] Low dielectric thermally conductive filler: 85 parts, which is a compound of hexagonal boron nitride nanosheets with a medium particle size of 3 micrometers, spherical silicon micropowder with a medium particle size of 3 micrometers, and amorphous aluminum nitride with a medium particle size of 2 micrometers, wherein the mass ratio of hexagonal boron nitride nanosheets to spherical silicon micropowder and amorphous aluminum nitride is 10:3:6.

[0076] Thermally conductive filler dispersant: 2 parts, octyltriethoxysilane;

[0077] Low volume shrinkage modifier: 10 parts, a cage-like silsesquioxane, specifically octavinyl cage-like polysilsesquioxane (Ecotion). ® POSS106).

[0078] Catalyst: 1 part, 5000 ppm Castrol platinum catalyst;

[0079] Polymerization inhibitor: 0.06 parts, 1-ethynyl-1-cyclohexanol;

[0080] Solvent: 5 parts, xylene, used to adjust the viscosity to 25000 mPa·s.

[0081] The preparation method of the above-mentioned conformal thermally conductive and insulating composite material includes the following steps:

[0082] S1. Add the low dielectric thermally conductive filler and thermally conductive filler dispersant into a high-speed disperser according to the ratio, and disperse them at 80°C and a dispersion speed of 500 rpm for 19 minutes.

[0083] S2. After the previous dispersion process, reduce the speed of the high-speed disperser to 150 rpm and increase the temperature to 100°C for dehydration and drying for 90 minutes.

[0084] S3. Place the dried thermally conductive filler from the previous step onto a vibrating screen to remove large-diameter filler particles. The mesh size of the vibrating screen is 1200 mesh.

[0085] S4. Add the organopolysilazane resin, toughening agent, crosslinking agent, low volume shrinkage modifier, and polymerization inhibitor into a planetary mixer according to the specified ratio, and disperse them at a low speed of 60 rpm for 5 minutes under a vacuum of less than -0.08 MPa.

[0086] S5. The thermally conductive filler prepared in step S3 is added to the planetary mixer in two batches for high-speed vacuum dispersion. Each batch is stirred and dispersed for 90 minutes at a speed of 400 rpm and a vacuum degree of less than -0.08 MPa.

[0087] S6. Add the catalyst and solvent to the mixture obtained in step S5 according to the specified ratio, and disperse it in a vacuum at a speed of 60 rpm for 4 minutes under a vacuum degree of less than -0.08 MPa to obtain a conformal thermally conductive and insulating composite material.

[0088] Example 3

[0089] This embodiment provides a conformal thermally conductive and insulating composite material, which comprises the following components by mass parts:

[0090] Organopolysilazane resin: 40 parts, which is methylhydropolysilazane with a viscosity of 20 cp and a hydrogen content of 0.9%;

[0091] Toughening agent: 4 parts, which is methylphenyl vinyl silicone resin, wherein the vinyl content is 1.4%, the phenyl content is 5%, and the viscosity is 3000 cs;

[0092] Crosslinking agent: 0.1 parts, which is methyl hydrogen-containing silicone resin (CAS No. 68988-57-8), with a hydrogen content of 0.2% and a viscosity of 20 cs;

[0093] Low dielectric thermally conductive filler: 35 parts, which is a compound of hexagonal boron nitride nanosheets with a medium particle size of 0.2 micrometers, spherical silicon micropowder with a medium particle size of 1 micrometer, and amorphous aluminum nitride with a medium particle size of 0.1 micrometers, wherein the mass ratio of hexagonal boron nitride nanosheets to spherical silicon micropowder and amorphous aluminum nitride is 10:1:1;

[0094] Thermally conductive filler dispersant: 0.3 parts, which is 3-(2,3-epoxypropoxy)propyltrimethoxysilane;

[0095] Low volume shrinkage modifier: 5 parts, a cage-like silsesquioxane, specifically a dimethylsiloxy cage-like polysilsesquioxane (Ecotion).® POSS1015);

[0096] Catalyst: 0.1 parts, which is 500 ppm Castrol platinum catalyst;

[0097] Polymerization inhibitor: 0.01 parts, which is diethyl maleate;

[0098] Solvent: 48 parts, hexamethyldisiloxane, used to adjust the viscosity to 12000 mPa·s.

[0099] The preparation method of the above-mentioned conformal thermally conductive and insulating composite material includes the following steps:

[0100] S1. Add the low dielectric thermally conductive filler and thermally conductive filler dispersant into a high-speed disperser according to the ratio, and disperse them at 2500 rpm for 3 minutes at 60°C.

[0101] S2. After the previous dispersion process, reduce the speed of the high-speed disperser to 50 rpm and increase the temperature to 120°C for dehydration and drying for 30 minutes.

[0102] S3. Place the dried thermally conductive filler from the previous step onto a vibrating screen to remove large-diameter filler particles. The mesh size of the vibrating screen is 1500 mesh.

[0103] S4. Add the organopolysilazane resin, toughening agent, crosslinking agent, low volume shrinkage modifier, and polymerization inhibitor into a planetary mixer according to the specified ratio, and disperse them at a low speed of 20 rpm for 15 minutes under a vacuum of less than -0.08 MPa.

[0104] S5. The thermally conductive filler prepared in step S3 is added to the planetary mixer in two batches for high-speed vacuum dispersion. Each batch is stirred and dispersed for 30 minutes at a speed of 800 rpm and a vacuum degree of less than -0.08 MPa.

[0105] S6. Add the catalyst and solvent to the mixture obtained in step S5 according to the specified ratio, and disperse it in a vacuum at a speed of 20 rpm for 8 minutes under a vacuum degree of less than -0.08 MPa to obtain a conformal thermally conductive and insulating composite material.

[0106] To further verify the technical effects of the present invention, comparative examples are set up based on Example 1 as follows:

[0107] Comparative Example 1

[0108] The only difference between this comparative example and Example 1 is that this comparative example does not contain a low volume shrinkage modifier.

[0109] Comparative Example 2

[0110] The only difference between this comparative example and Example 1 is that this comparative example does not contain a toughening agent.

[0111] Comparative Example 3

[0112] The only difference between this comparative example and Example 1 is that the preparation method of this comparative example does not include step S3.

[0113] Comparative Example 4

[0114] This comparative example uses commercially available epoxy-based thermally conductive composite slurry.

[0115] Comparative Example 5

[0116] The only difference between this comparative example and Example 1 is that the low dielectric thermally conductive filler is replaced with an equal number (60 parts) of hexagonal boron nitride nanosheets with a medium particle size of 1.5 micrometers.

[0117] Comparative Example 6

[0118] The only difference between this comparative example and Example 1 is that the low dielectric thermally conductive filler is replaced with an equal number (60 parts) of spherical silicon micropowder with a medium particle size of 3 micrometers.

[0119] Comparative Example 7

[0120] The only difference between this comparative example and Example 1 is that the low dielectric thermally conductive filler is replaced with an equal number (60 parts) of amorphous aluminum nitride with a medium particle size of 0.1 micrometers.

[0121] Comparative Example 8

[0122] The only difference between this comparative example and Example 1 is that the low dielectric thermally conductive filler is replaced with an equal number (60 parts) of a binary compound of hexagonal boron nitride nanosheets and spherical silicon powder, with a mass ratio of hexagonal boron nitride nanosheets to spherical silicon powder of 10:3.

[0123] Comparative Example 9

[0124] The only difference between this comparative example and Example 1 is that the low dielectric thermally conductive filler is replaced with an equal number (60 parts) of a binary composite of hexagonal boron nitride nanosheets and amorphous aluminum nitride, with a mass ratio of 10:1.

[0125] Comparative Example 10

[0126] The only difference between this comparative example and Example 1 is that the low dielectric thermally conductive filler is replaced with an equal number (60 parts) of a binary compound of spherical silicon micropowder and amorphous aluminum nitride, with a mass ratio of 3:1.

[0127] Comparative Example 11

[0128] The only difference between this comparative example and Example 1 is that the hexagonal boron nitride nanosheets have a particle size of 7 micrometers.

[0129] Comparative Example 12

[0130] The only difference between this comparative example and Example 1 is that the particle size in the amorphous aluminum nitride is 5 micrometers.

[0131] Comparative Example 13

[0132] The only difference between this comparative example and Example 1 is that the mass ratio of hexagonal boron nitride nanosheets, spherical silicon micropowder, and amorphous aluminum nitride is 15:3:1.

[0133] Comparative Example 14

[0134] The only difference between this comparative example and Example 1 is that the mass ratio of hexagonal boron nitride nanosheets, spherical silicon micropowder, and amorphous aluminum nitride is 5:3:1.

[0135] The composite materials obtained in Examples 1-3 and Comparative Examples 1-14 were subjected to the following performance tests:

[0136] Dielectric constant test

[0137] The composite material was cured into a film, and the dielectric constant was tested according to the ASTM D150 standard, with the test frequency set to 1MHz.

[0138] Shrinkage test

[0139] The volume shrinkage rate β is calculated by measuring the density (ρ0, ρ1) and mass (m0, m1) before and after treatment: β = [(m0 / ρ0 - m1 / ρ1) / m0 / ρ0] × 100%.

[0140] Thermal conductivity simulation test

[0141] The composite material was uniformly sprayed onto the upper and lower surfaces of a uniformly sized aluminum substrate and cured. Specifically, the solvent was removed by heating at 60°C for 30 minutes, pre-curing was performed at 90°C for 120 minutes, and finally, it was thermally cured at 160°C under nitrogen protection for 3 hours to form a solid composite material coating with a thickness of 25 μm. Two sprayed aluminum substrates were then secured with screws and placed on a thermal resistance tester to test the overall thermal resistance of the fixture according to ASTM D5470 standard.

[0142] Temperature resistance test

[0143] Similarly, the composite material was uniformly sprayed onto the upper and lower surfaces of a uniformly sized aluminum substrate and cured. Specifically, the solvent was removed by heating at 60℃ for 30 minutes, pre-curing was performed at 90℃ for 120 minutes, and finally, it was thermally cured at 160℃ under nitrogen protection for 3 hours to form a solid composite material coating with a thickness of 25μm. The individually coated aluminum substrates were placed in a 200℃ oven and a -40℃~180℃ thermal cycling chamber for 500 hours of aging. After aging, a withstand voltage test (DC) was performed.

[0144] Application testing

[0145] Following ASTM D-257 standards, the composite material was uniformly sprayed onto a uniformly sized SIR plate and cured to a coating thickness of 25 μm. It was then aged for 200 hours in an environmental chamber with 85% RH and 90°C. After aging, a withstand voltage test was performed. Finally, a surface insulation resistance test was conducted.

[0146] The test results are shown in Table 1 below:

[0147] Table 1 Performance test results of the examples and comparative examples

[0148]

[0149] As can be seen from the test results in Table 1, the conformal thermally conductive and insulating composite material prepared in the embodiments of the present invention performs excellently in all performance tests and has significant technical advantages compared with the comparative examples.

[0150] Regarding shrinkage, the volume shrinkage of the embodiment was extremely low, significantly better than that of Comparative Example 1. This indicates that cage-type silsesquioxane, as a low-volume-shrinkage modifier, can effectively suppress volume shrinkage during the curing process of polysilazane, thereby preventing interface cracking and detachment.

[0151] Regarding thermal conductivity, the tooling thermal resistance of the embodiments was significantly lower than that of the comparative examples. This fully demonstrates the importance of the introduction of toughening agent, the vibrating screen grading process, and the synergistic effect of the ternary composite filler system in constructing an efficient thermal conductivity pathway. Among them, Comparative Example 2, due to the lack of toughening agent, resulted in poor compatibility between the filler and the matrix interface, leading to a significant increase in thermal resistance. Comparative Example 3 omitted the vibrating screen grading step, and the presence of large-diameter particles disrupted the compact packing of the filler, also causing a deterioration in thermal resistance. Comparative Example 4, as a commercially available epoxy-based product, had a thermal resistance as high as 0.8315℃ / W, which was far inferior to the embodiments of the present invention.

[0152] Regarding dielectric properties, the dielectric constant of the embodiments was well controlled within the excellent range of 4.8-5.4, significantly lower than that of Comparative Examples 4, 7, and 10. This further illustrates the synergistic effect of the ternary composite filler system in coordinating dielectric constant and thermal conductivity.

[0153] In terms of temperature resistance and long-term reliability, the tested examples maintained an excellent withstand voltage of over 20kV after aging at 200℃ and thermal cycling from -40℃ to 180℃, and the surface insulation resistance remained at 10 kV. 12 -10 13 The voltage drop was on the order of Ω. In contrast, Comparative Example 1, lacking a low-shrinkage modifier, experienced a sharp drop in withstand voltage to 11kV after aging at 200℃, and only 2.5kV after thermal cycling, with its surface insulation resistance decreasing to 10 Ω. 10Ω; Comparative Example 3 also showed a significant decrease in temperature resistance due to the lack of filler grading treatment; Comparative Example 7 showed severe deterioration in voltage resistance and surface insulation resistance after thermal cycling aging; Comparative Example 4, as a commercially available product, exhibited the worst performance in all temperature resistance indicators. These comparative results clearly demonstrate that low volume shrinkage modifiers are crucial for maintaining the structural integrity and interfacial stability of the cured coating, and that combining them with filler grading treatment can effectively eliminate stress concentration points and electrically weak areas.

[0154] Regarding process feasibility, Comparative Examples 5, 9, and 13 suffered from excessively high slurry viscosity due to improper filler ratios or particle size selection, rendering them unusable materials. This demonstrates the crucial impact of component ratio balance and particle size matching on processing performance in the ternary composite system. Comparative Examples 11 and 12, using excessively large hexagonal boron nitride nanosheets and amorphous aluminum nitride, respectively, exhibited acceptable shrinkage and dielectric properties, but significantly increased thermal resistance. This indicates that optimizing filler particle size is of significant engineering importance in balancing processing flowability and thermal conductivity network density. In Comparative Example 14, reducing the proportion of hexagonal boron nitride nanosheets resulted in a significant increase in thermal resistance, further confirming the core role of high-content plate-like boron nitride in constructing in-plane thermal conductivity pathways.

[0155] In summary, the conformal thermally conductive and insulating composite material obtained by this invention, through the temperature resistance advantage of the organopolysilazane resin matrix, the synergistic effect of the ternary composite filler, the structural stabilizing effect of the low volume shrinkage modifier, and the interfacial strengthening mechanism of the toughening agent, exhibits significant advantages in terms of low shrinkage, low thermal resistance, resistance to aging over a wide temperature range, and high insulation reliability. It can meet the stringent requirements for thermal management materials in the fields of three-dimensional integrated circuits and high-end equipment manufacturing.

[0156] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and such modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A conformal thermally conductive and insulating composite material, characterized in that, The following components are included by mass parts: Organopolysilazane resin: 50-60 parts; the organopolysilazane resin is vinyl hydropolysilazane or vinyl polysilazane; Toughening agent: 7-10 parts; Crosslinking agent: 1.9-3 parts; Low-dielectric thermally conductive filler: 60-85 parts, wherein the low-dielectric thermally conductive filler is a compound of hexagonal boron nitride nanosheets, spherical silicon micropowder and amorphous aluminum nitride; the medium particle size of the hexagonal boron nitride nanosheets is 0.2-3 micrometers, the medium particle size of the spherical silicon micropowder is 1-3 micrometers, and the medium particle size of the amorphous aluminum nitride is 0.1-2 micrometers; the mass ratio of the hexagonal boron nitride nanosheets, spherical silicon micropowder and amorphous aluminum nitride is 10:(1-3):(1-6); Thermally conductive filler dispersant: 1.1-2 parts; Low volume shrinkage modifier: 8-10 parts, wherein the low volume shrinkage modifier is a cage-type silsesquioxane; Catalyst: 0.5-1 part; Polymerization inhibitor: 0.04-0.06 parts; Solvent: 5-90 parts; The toughening agent is methylphenyl vinyl silicone resin, wherein the vinyl content is 1.2-1.3%, the phenyl content is 18-30%, and the viscosity is 90,000-200,000 cs; The preparation method of the conformal thermally conductive and insulating composite material includes the following steps: S1. Mix the low dielectric thermally conductive filler and the thermally conductive filler dispersant, and disperse them at 500-2500 rpm for 3-19 minutes at 60-80℃. S2. Heat the mixture obtained in step S1 to 100-120℃ and dehydrate and dry it at a speed of 50-150 rpm for 30-90 minutes. S3. The material dried in step S2 is sieved to remove large-diameter particles and obtain the processed thermally conductive filler. S4. Mix the organopolysilazane resin, toughening agent, crosslinking agent, low volume shrinkage modifier and polymerization inhibitor, and disperse them under vacuum at a speed of 20-60 rpm for 5-15 minutes. S5. Add the thermally conductive filler treated in step S3 to the mixture in step S4 in two batches, and disperse it under vacuum conditions at a speed of 400-800 rpm for 30-90 minutes each time. S6. Add the catalyst and solvent to the mixture obtained in step S5, and disperse it under vacuum at a speed of 20-60 rpm for 4-8 minutes to obtain the conformal thermally conductive and insulating composite material.

2. The conformal thermally conductive and insulating composite material as described in claim 1, characterized in that, The organopolysilazane resin has a viscosity of 11,000-20,000 cp, a hydrogen content of 0-0.45%, and a vinyl content of 0.9-1.8%.

3. The conformal thermally conductive and insulating composite material as described in claim 1, characterized in that, The crosslinking agent is a methyl hydrogen-containing silicone resin, wherein the hydrogen content is 0.6-0.8% and the viscosity is 160-300 cs.

4. The conformal thermally conductive and insulating composite material as described in claim 1, characterized in that, The cage-like silsesquioxane is selected from one of dimethylsiloxy cage-like polysilsesquioxane and octavinyl cage-like polysilsesquioxane.

5. The conformal thermally conductive and insulating composite material as described in claim 1, characterized in that, The catalyst is a 3000-5000ppm castor platinum catalyst.

6. A method for preparing a conformal thermally conductive and insulating composite material as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Mix the low dielectric thermally conductive filler and the thermally conductive filler dispersant, and disperse them at 500-2500 rpm for 3-19 minutes at 60-80℃. S2. Heat the mixture obtained in step S1 to 100-120℃ and dehydrate and dry it at a speed of 50-150 rpm for 30-90 minutes. S3. The material dried in step S2 is sieved to remove large-diameter particles and obtain the processed thermally conductive filler. S4. Mix the organopolysilazane resin, toughening agent, crosslinking agent, low volume shrinkage modifier and polymerization inhibitor, and disperse them under vacuum at a speed of 20-60 rpm for 5-15 minutes. S5. Add the thermally conductive filler treated in step S3 to the mixture in step S4 in two batches, and disperse it under vacuum conditions at a speed of 400-800 rpm for 30-90 minutes each time. S6. Add the catalyst and solvent to the mixture obtained in step S5, and disperse it under vacuum at a speed of 20-60 rpm for 4-8 minutes to obtain the conformal thermally conductive and insulating composite material.

7. The method for applying the conformal thermally conductive and insulating composite material as described in any one of claims 1-5 in three-dimensional integrated circuits, characterized in that, Includes the following steps: A1. Inject or coat the conformal thermally conductive and insulating composite material into the gaps between stacked chips of a three-dimensional integrated circuit; A2. Heat at 50-70℃ for 10-50 minutes to remove the solvent; A3. Pre-curing is carried out at 80-100℃ for 1-3 hours; A4. Finally, perform final heat curing at 150-180℃ under nitrogen protection for 1-5 hours to form a solid composite material interface layer.

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