One-component heat-curing addition type silicone adhesive for chip packaging and preparation method thereof

Abstract

This application relates to the field of adhesive technology, specifically to a one-component thermosetting addition-curing silicone adhesive for chip packaging and its preparation method. The one-component thermosetting addition-curing silicone adhesive for chip packaging comprises the following raw material components in parts by weight: 40-60 parts electronic-grade vinyl silicone oil, 5-15 parts vinyl MQ silicone resin, 1-3 parts colorant, 8-12 parts special-structure vinyl silicone oil, 3-8 parts end-side hydrogen-containing silicone oil, 0.1-0.15 parts platinum catalyst, 0.01-0.1 parts inhibitor, 1-3 parts self-made tackifier, and 35-75 parts composite filler; the composite filler includes graphene-coated alumina, silica, and carboxyl-functionalized boron nitride. The one-component thermosetting addition-curing silicone adhesive for chip packaging in this application improves upon the existing problems of low shear strength and poor thermal stability, resulting in a one-component thermosetting addition-curing silicone adhesive that balances shear strength, thermal stability, and long-term storage performance.

Description

Technical Field

[0001] This application relates to the field of adhesive technology, specifically to a one-component thermosetting addition-curing silicone adhesive for chip packaging and its preparation method. Background Technology

[0002] As microelectronic packaging technology rapidly evolves towards higher integration and higher power density, adhesives for chip packaging have become indispensable key materials for ensuring system reliability. They not only need to achieve stable mechanical bonding between the chip and the substrate, efficient heat dissipation, and reliable insulation, but also require excellent long-term durability under complex operating conditions. Among numerous technical approaches, addition-cure silicone adhesives have gradually become an ideal choice for high-end packaging applications due to their outstanding advantages such as no small molecule release during curing, low shrinkage, easy reaction control, and environmental friendliness. However, this system still faces a series of inherent challenges in practical application: the large amount of inorganic filler used to achieve high thermal conductivity often severely damages the rheological properties and process applicability of the colloid; the single-component systems developed for ease of operation have an extremely fragile balance between storage stability and reactivity; more importantly, the lack of strong interaction between the non-polar silicone network and common substrates (such as metals, ceramics, and plastics) results in interfacial adhesion strength, especially long-term adhesion at high temperatures, becoming a core weakness restricting its reliability.

[0003] Current technological improvements often focus on optimizing single properties, lacking systematic and synergistic enhancement solutions. For example, introducing tackifiers can improve initial adhesion, but residual catalysts (such as organotin) from traditional tackifier synthesis can easily poison the platinum catalyst in subsequent addition curing, jeopardizing storage stability and curing completeness. Special fillers (such as cerium oxide) added to improve heat resistance may introduce environmental and compatibility issues. Furthermore, after long-term thermal cycling or high-temperature storage, interfacial chemical bonds are prone to breakage, leading to adhesive failure and colloid detachment. Therefore, developing a simple synthesis route for a single-component thermosetting addition-curing silicone adhesive that simultaneously ensures shear strength, heat resistance, and long-term storage has become an urgent technological requirement for driving the development of advanced packaging technologies. Summary of the Invention

[0004] To effectively address the aforementioned issues, this application provides a one-component thermosetting addition-curing silicone adhesive for chip packaging and its preparation method, resulting in a one-component thermosetting addition-curing silicone adhesive that balances shear strength and heat resistance stability.

[0005] The single-component thermosetting addition-curing silicone adhesive for chip packaging provided in this application adopts the following technical solution: A single-component thermosetting addition-curing silicone adhesive for chip packaging comprises the following raw material components in parts by weight: 40-60 parts electronic-grade vinyl silicone oil, 5-15 parts vinyl MQ silicone resin, 1-3 parts color paste, 8-12 parts special-structure vinyl silicone oil, 3-8 parts end-side hydrogen-containing silicone oil, 0.1-0.15 parts platinum catalyst, 0.01-0.1 parts inhibitor, 1-3 parts self-made tackifier, and 35-75 parts composite filler; wherein the composite filler includes graphene-coated alumina, silica, and carboxyl-functionalized boron nitride.

[0006] Electronic-grade vinyl silicone oil serves as the base polymer, providing the main structure and flexibility. The addition reaction of a specially structured vinyl silicone oil and hydrogen-containing silicone oil achieves thermosetting crosslinking, enhancing the crosslinking density and mechanical strength of the system. Vinyl MQ silicone resin, as a reinforcing filler, adjusts the system's modulus and thixotropic properties, forming a crosslinking network with the specially structured vinyl silicone oil and end-side hydrogen-containing silicone oil. This ensures low modulus and high elasticity while improving cohesive strength, optimizing the balance between elastic modulus and adhesive strength. Self-made tackifiers and composite fillers enhance the adhesive's adhesion to inorganic surfaces and provide excellent shear strength and heat stability. The combined effect of these components results in a single-component thermosetting addition-curing silicone adhesive with high shear strength and heat stability, while ensuring no small molecule release and reduced shrinkage during curing. In this composite filler, graphene-coated alumina, silica, and carboxyl-functionalized boron nitride work together to create an enhanced system with high shear strength, excellent thermal stability, and long-term storage performance. Firstly, the two-dimensional sheet structure of graphene and silica nanoparticles form a three-dimensional stable rigid-semi-rigid composite network framework. This network framework acts as an efficient stress transfer pathway within the colloid, constructing a highly efficient and uniform stress transfer framework, thus laying the mechanical foundation for high shear strength. Simultaneously, the interaction between this rigid-semi-rigid composite network framework and the composite filler effectively controls the elastic modulus of the adhesive layer, avoiding stress concentration caused by excessively high modulus in traditional high-filler systems. This achieves low-modulus, high-elasticity mechanical properties, perfectly matching the low-stress packaging requirements of MEMS devices. The addition of carboxyl-functionalized boron nitride further enhances the stress transmission pathway and thermal conductivity, thereby improving the material's heat resistance and stability. Simultaneously, during the curing phase, the system viscosity decreases and molecular motion intensifies. The carboxyl groups on the surface of the carboxyl-functionalized boron nitride react with the self-made tackifier, anchoring the composite filler within the flexible polymer network. This significantly enhances the tensile and shear strength of the material, purifies the curing environment, and allows the platinum catalyst to fully exert its catalytic efficiency. Furthermore, the carboxyl-functionalized boron nitride is firmly integrated into the crosslinking network, anchoring the composite filler within the flexible polymer network, significantly enhancing the tensile and shear strength of the material. This reduces internal stress accumulation and microcrack initiation caused by mismatched coefficients of thermal expansion, allowing the adhesive layer to maintain excellent mechanical integrity and bonding reliability even after long-term high-temperature cycling, thus improving the overall shear strength, heat resistance, and long-term storage performance of the adhesive material.

[0007] Preferably, the preparation method of the self-made tackifier includes: (1) taking dimethyl dimethoxysilane, methyl vinyl dimethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane and tetraethyl orthosilicate in sequence and adding them to ethylene glycol, then stirring and adding resin catalyst and water to react, and then processing to obtain polysiloxane oligomer; (2) adding isopropanol solution containing tetrabutyl titanate, reacting at 60-80℃ for 2-4h, adding magnesium oxide, and rotary evaporating to obtain the self-made tackifier.

[0008] The self-made tackifier introduces active functional groups such as epoxy and methacryloxy groups through silane hydrolysis condensation and titanate catalytic crosslinking. It matches the reactivity of the organosilicon matrix and the surface characteristics of the substrate, provides bonding sites and introduces flexible segments. Unlike the physical adsorption tackifier of ordinary tackifiers, it improves the adhesion of the adhesive to inorganic surfaces such as chips and substrates, making the bond stronger and more stable.

[0009] The inventors discovered that carboxyl-functionalized boron nitride yields a porous composite structure. By introducing carboxyl groups, during the heat curing period, as the system's fluidity increases, the epoxy functional groups of the tackifier react with their carboxyl groups, anchoring them within the cross-linked network to form a chemically bonded interface with extremely high heat resistance. This not only improves the adhesion of the adhesive to inorganic surfaces such as chips and substrates but also enhances the bonding between the filler and the matrix, thereby ensuring the elasticity and thermal stress absorption capacity of the adhesive layer.

[0010] Preferably, the preparation method of carboxyl-functionalized boron nitride includes: (1) dissolving hexadecyltrimethylammonium bromide in a mixture of water and ethanol, adding tetraethyl orthosilicate and ammonia water and stirring to obtain SiO2 precursor, then adding boric acid and urea and grinding and mixing, and reacting at 800-1000℃ for 5-6 hours under an ammonia atmosphere to obtain boron nitride complex; (2) dispersing the boron nitride complex in toluene, adding carboxylsilane, and reacting for 10-12 hours to obtain carboxyl-functionalized boron nitride.

[0011] More preferably, the mass ratio of boron nitride complex to carboxysilane is 1:(0.8-1).

[0012] Preferably, the preparation method of graphene-coated alumina includes: weighing alumina, adding it to ethanol and water for dispersion, adding a silane coupling agent, reacting and dispersing it in water to obtain a suspension, slowly adding the graphene oxide powder dispersion to the suspension, heating to 65-80℃ and reacting for 8-12 hours, drying, and then, under a protective atmosphere, heating to 350-400℃ and reacting for 1-3 hours to obtain graphene-coated alumina.

[0013] Preferably, the mass ratio of graphene-coated alumina, silica, and carboxyl-functionalized boron nitride is (5-8):(3-5):(2-4).

[0014] More preferably, the mass ratio of graphene-coated alumina, silica, and carboxyl-functionalized boron nitride is 7:4:3.

[0015] By synthesizing a silica precursor and then loading boron nitride in situ onto the silica to form a composite, a porous SiO2 framework is created. This porous structure allows for elastic compression and rebound under stress, absorbing significant amounts of stress and providing additional deformation capacity before molecular chain breakage. The well-dispersed boron nitride within the pores provides a thermally conductive pathway, improving the material's temperature resistance. Furthermore, the carboxyl groups on its surface react with the epoxy groups of the tackifier during curing, strengthening interfacial bonding and stress transfer efficiency. Simultaneously, this structure, together with graphene-coated alumina and silica filler components, constructs a thermally conductive network, enhancing thermal conductivity. The high thermal stability of carboxyl-functionalized boron nitride and its interaction with tackifiers and other components effectively suppress the thermal motion and desorption of polymer chains at high temperatures, preventing performance degradation due to precipitation interfaces and ensuring the adhesive possesses high shear strength, low modulus, high elasticity, and heat resistance. Therefore, if there is too little carboxysilane, the chemical synergistic effect of the tackifier is weakened, reducing interfacial bonding and stress transfer efficiency, resulting in a decrease in tensile and shear strength; if there is too much carboxysilane, it is not conducive to storage stability, and shear bond strength may also decrease.

[0016] The graphene coating forms a two-dimensional interconnected network between alumina particles, which can effectively transfer and disperse stress under stress and inhibit crack propagation. At the same time, the slippage of the graphene sheets themselves can also dissipate some energy. Alumina provides intrinsic thermal conductivity, and the graphene coating greatly reduces the interfacial thermal resistance between alumina particles, forming an efficient heat transfer pathway.

[0017] By leveraging the intrinsic thermal conductivity of alumina in graphene-coated alumina, and utilizing the high specific surface area and surface silanol groups of silica, a thermally conductive network is constructed, further enhancing the thixotropic and mechanical properties of the colloid. Simultaneously, the surface active groups of graphene-coated alumina can interact with carboxyl-functionalized boron nitride, further strengthening the three-dimensional thermally conductive network. This improves thermal conductivity while ensuring high shear strength, long-term storage stability, and heat resistance.

[0018] Preferably, the inhibitor is one or more of ethynylcyclohexanol, methylbutynol, ethynyltert-butanol, and phenylbutynol.

[0019] Secondly, this application provides a method for preparing a one-component thermosetting addition-curing silicone adhesive for chip packaging, using the following technical solution: A method for preparing a single-component thermosetting addition-curing silicone adhesive for chip packaging includes the following steps: (1) Electronic grade vinyl silicone oil, special structure vinyl silicone oil, vinyl MQ silicone resin, color paste, and composite filler are added sequentially, stirred and mixed, heated to 90-100℃, and dehydrated under vacuum to obtain a base adhesive; (2) Inhibitors, self-made tackifiers, and end-side hydrogen-containing silicone oil are added to the base adhesive and stirred and reacted, then a platinum catalyst is added, stirred and mixed under vacuum, and degassed under vacuum to obtain a single-component thermosetting addition-curing silicone adhesive for chip packaging.

[0020] Preferably, the stirring reaction conditions in (2) are stirring at a temperature of 10-20℃ and a speed of 15-200rpm for 20-30min.

[0021] In summary, this application includes at least one of the following beneficial technical effects: 1. In this application, electronic-grade vinyl silicone oil is used as the main base polymer to provide the main structure and flexibility; the addition reaction of special structure vinyl silicone oil and side-containing hydrogen silicone oil realizes thermosetting crosslinking, which enhances the crosslinking density and mechanical strength of the system; the self-made tackifier and composite filler improve the adhesion of the adhesive to inorganic surfaces and have excellent shear strength and heat resistance stability.

[0022] 2. By leveraging the intrinsic thermal conductivity of alumina in graphene-coated alumina, and further enhancing the thixotropic and mechanical properties of the colloid through the high specific surface area and surface silanol groups of silica, a thermally conductive network can be constructed. At the same time, the active groups on the surface of graphene-coated alumina can also interact with carboxyl-functionalized boron nitride, thereby improving thermal conductivity while further ensuring the adhesive's comprehensive properties such as high strength, long-term storage stability, and excellent heat resistance. Detailed Implementation

[0023] Electronic grade vinyl silicone oil: RH-Vi1000E; Special structure vinyl silicone oil: RH-Vi306B Runhe Materials; Pigment paste: BASF 0066 pigment paste; End-side hydrogen-containing silicone oil: RH-LHC-2 (Ningbo Runhe) with a hydrogen content of 0.79%; Platinum catalyst: TJ-P-2500 from Guangzhou Tianjiang High-Tech Materials Co., Ltd.; Inhibitor: Ethynylcyclohexanol; Alumina: AS-50; Graphene oxide powder: Changzhou Sixth Element SE2430; Silica: Evonik AEROSIL®200; Boron nitride (200-3000 mesh): purchased from Hebei Ruihuang Metal Materials Co., Ltd.; Ammonia (mass fraction: 28%); Carboxysilane: CarboxyPEG silane, product number: PS2-CML-2K, purchased from Shanghai Pengshuo Biotechnology Co., Ltd.; Resin catalyst: LDX604; Silane coupling agent: KH-560; Other raw materials are commercially available.

[0024] Preparation Example 1 Preparation of homemade thickener: (1) Add 65g of ethylene glycol to a 500mL three-necked flask, then add 32g of dimethyldimethoxysilane, 22g of methylvinyldimethoxysilane, 26g of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 26g of 3-(methacryloyloxy)propyltrimethoxysilane, and slowly add 42g of tetraethyl orthosilicate and stir until homogeneous. Then add 8.5g of resin catalyst, slowly add 22.5g of water, and heat up. The reaction was carried out at 60°C for 4 hours under nitrogen protection. After the reaction was completed, the mixture was neutralized to neutral with 10% sodium bicarbonate solution, filtered, washed with water until neutral, and the organic layer was distilled under reduced pressure at 90°C and vacuum degree -0.09MPa to obtain polysiloxane oligomer; (2) 20g of isopropanol solution containing 2g of titanate n-butyl ester was added and the mixture was reacted at 70°C for 3 hours. Magnesium oxide was added and the mixture was rotary evaporated at 110°C and vacuum degree -0.1MPa to obtain the self-made thickener.

[0025] Preparation Example 2 Preparation of graphene-coated alumina: The steps are as follows: 100g of alumina was calcined at 400℃ for 2h, then 200ml of ethanol and 50ml of water were added and dispersed evenly. 1.5g of silane coupling agent was added, and under nitrogen protection, the temperature was raised to 75℃ and refluxed for 6h. After centrifugation and washing, the alumina was dispersed in 200mL of water to obtain a suspension. A dispersion containing 3.0g of graphene oxide powder in 200mL of water was slowly added dropwise to the suspension. The pH of the system was adjusted to 9 with ammonia. The temperature was raised to 80℃ and reacted for 12h. After filtration, washing, and drying, the alumina was heated to 350℃ and reacted for 1.5h under argon atmosphere to obtain graphene-coated alumina.

[0026] Preparation Example 3 Preparation of modified alumina: The steps are as follows: 100g of alumina filler is added to 500g of 50% ethanol aqueous solution and sonicated for 30min to form a suspension; 0.5g of KH-550 is added and stirred at 60℃ for 2h; the pH is adjusted to 5 with hydrochloric acid; the mixture is centrifuged; washed 3 times with water; and vacuum dehydrated at 100℃ for 1h to obtain modified alumina.

[0027] Preparation Example 4 Preparation of carboxyl-functionalized boron nitride: (1) Take 4 parts of hexadecyltrimethylammonium bromide and dissolve it in a mixture of 480 parts of water and 120 parts of ethanol. Add 20 parts of tetraethyl orthosilicate dropwise under stirring and slowly add 10 parts of 28% ammonia water. Stir and react for 24 hours. Centrifuge, wash with ethanol 3 times, and dry at 60°C to obtain SiO2 precursor. Add 10 parts of boric acid and 15 parts of urea and grind and mix. Place in a tube furnace and heat to 1000°C at 3°C / min under ammonia atmosphere for 5 hours to obtain boron nitride complex. (2) Take 5 parts of boron nitride complex and disperse it in 200 parts of toluene. Add 4 parts of carboxyl PEG silane and react for 12 hours. Filter, wash with toluene and ethanol 3 times respectively, and dry under vacuum at 80°C for 8 hours to obtain carboxyl-functionalized boron nitride.

[0028] Preparation Example 5 Preparation of carboxyl-functionalized boron nitride: (1) Take 4 parts of hexadecyltrimethylammonium bromide and dissolve it in a mixture of 480 parts of water and 120 parts of ethanol. Add 20 parts of tetraethyl orthosilicate dropwise under stirring and slowly add 10 parts of 28% ammonia water. Stir and react for 24 hours. Centrifuge, wash with ethanol 3 times, and dry at 60°C to obtain SiO2 precursor. Add 10 parts of boric acid and 15 parts of urea and grind and mix. Place in a tube furnace and heat to 1000°C at 3°C / min under ammonia atmosphere for 5 hours to obtain boron nitride complex. (2) Take 5.5 parts of boron nitride complex and disperse it in 200 parts of toluene. Add 3.5 parts of carboxyl PEG silane and react for 12 hours. Filter, wash with toluene and ethanol 3 times respectively, and dry under vacuum at 80°C for 8 hours to obtain carboxyl-functionalized boron nitride.

[0029] Preparation Example 6 Preparation of carboxyl-functionalized boron nitride: (1) Take 4 parts of hexadecyltrimethylammonium bromide and dissolve it in a mixture of 480 parts of water and 120 parts of ethanol. Add 20 parts of tetraethyl orthosilicate dropwise under stirring and slowly add 10 parts of 28% ammonia water. Stir and react for 24 hours. Centrifuge, wash with ethanol 3 times, and dry at 60°C to obtain SiO2 precursor. Add 10 parts of boric acid and 15 parts of urea and grind and mix. Place in a tube furnace and heat to 1000°C at 3°C / min under ammonia atmosphere for 5 hours to obtain boron nitride complex. (2) Take 4 parts of boron nitride complex and disperse it in 200 parts of toluene. Add 5 parts of carboxyl PEG silane and react for 12 hours. Filter, wash with toluene and ethanol 3 times respectively, and dry under vacuum at 80°C for 8 hours to obtain carboxyl-functionalized boron nitride. Example 1 A method for preparing a single-component thermosetting addition-curing silicone adhesive for chip packaging includes the following steps: (1) In a double planetary mixer, 40 parts of electronic-grade vinyl silicone oil, 10 parts of special-structure vinyl silicone oil, 5 parts of vinyl MQ silicone resin, 1.5 parts of color paste, and 40 parts of composite filler are added sequentially. The composite filler is graphene-coated alumina, silica, and carboxyl-functionalized boron nitride prepared in Preparation Example 2, with a mass ratio of 7:4:3. The mixture is stirred and mixed at 500 rpm for 30 min. After heating to 80°C, vacuum dehydrate for 1 hour to obtain the base adhesive; (2) at room temperature, transfer the base adhesive to a homogenizer, add 0.1 parts of inhibitor, 3 parts of the self-made tackifier prepared in Preparation Example 1, and 4 parts of end-side hydrogen-containing silicone oil. Stir at 80°C and 200 rpm for 20 minutes, cool to room temperature, add 0.1 parts of platinum catalyst, and under temperature control of 10°C, vacuum stir and mix for 20 minutes, vacuum degas for 30 minutes, and seal and store after discharge to obtain a single-component thermosetting addition-curing silicone adhesive for chip packaging. Example 2

[0030] The difference between this embodiment and Example 1 is that the composite filler is graphene-coated alumina and silica prepared in Preparation Example 2 with a mass ratio of 6:4:4, and carboxyl-functionalized boron nitride prepared in Preparation Example 4. Example 3

[0031] The difference between this embodiment and Example 1 is that the composite filler is graphene-coated alumina and silica prepared in Preparation Example 2 with a mass ratio of 4:4:6, and carboxyl-functionalized boron nitride prepared in Preparation Example 4. Example 4

[0032] The difference between this embodiment and Example 1 is that the composite filler is graphene-coated alumina and silica prepared in Preparation Example 2 with a mass ratio of 9:4:1, and carboxyl-functionalized boron nitride prepared in Preparation Example 4. Example 5

[0033] The difference between this embodiment and Example 1 is that the composite filler is graphene-coated alumina and silica prepared in Preparation Example 2 with a mass ratio of 7:4:3, and carboxyl-functionalized boron nitride prepared in Preparation Example 5. Example 6

[0034] The difference between this embodiment and Example 1 is that the composite filler is graphene-coated alumina and silica prepared in Preparation Example 2 with a mass ratio of 7:4:3, and carboxyl-functionalized boron nitride prepared in Preparation Example 6.

[0035] Comparative Example 1 The difference between this comparative example and Example 1 is that 3 parts of the homemade tackifier prepared in Preparation Example 1 were replaced with 3 parts of Dow Corning Z-6300 vinyltrimethoxysilane.

[0036] Comparative Example 2 The difference between this comparative example and Example 1 is that the composite filler is modified alumina and silica prepared in Preparation Example 3 and carboxyl-functionalized boron nitride prepared in Preparation Example 4, with a mass ratio of 7:4:3.

[0037] Comparative Example 3 The difference between this comparative example and Example 1 is that the composite filler is the graphene-coated alumina, silica, and boron nitride prepared in Preparation Example 2 with a mass ratio of 7:4:3.

[0038] Comparative Example 4 The difference between this comparative example and Example 1 is that the composite filler is alumina, silica, and carboxyl-functionalized boron nitride prepared in Example 4, with a mass ratio of 7:4:3.

[0039] Comparative Example 5 The difference between this comparative example and Example 1 is that the composite filler is the graphene-coated alumina and silica prepared in Preparation Example 1 with a mass ratio of 10:4.

[0040] Comparative Example 6 The difference between this comparative example and Example 1 is that the composite filler is graphene-coated alumina prepared in Preparation Example 1 and carboxyl-functionalized boron nitride prepared in Preparation Example 3, with a mass ratio of 11:3.

[0041] The single-component thermosetting addition-curing silicone adhesive for chip packaging prepared in the examples and comparative examples was cured at 150℃+1h. (1) Heat resistance test: The test was conducted according to the MIL-STD-883 Method 2019 standard. The specific method is as follows: The chip (approximately 1mm×1mm in size) was bonded to the PCB board with the adhesive prepared in the examples, and the curing conditions were 150℃ / 1h. After curing, the samples were placed in a constant temperature chamber at room temperature and at 300℃ for 72h, respectively, and then the push force was tested using a push-pull force tester. The test speed is 50-200μm / s. The pusher pushes the chip horizontally in a constant direction perpendicular to the side of the chip until the chip falls off the PCB board or the adhesive layer fails. Record the maximum push force value (unit: N). Divide the maximum push force value by the chip bonding area (mm²) to calculate the PCB board-chip push bond strength (unit: MPa). (2) Hardness: The Shore hardness tester is used for testing. (3) Elastic modulus: The test standard is ASTM D412. The test results are shown in Table 1.

[0042] Table 1 Performance Test Results Experimental data show that the single-component thermosetting addition-curing silicone adhesives for chip packaging prepared in Examples 1-6 of this application exhibit higher strength, superior adhesive shear properties, better thermal conductivity, and better temperature and aging resistance compared to those in Comparative Examples 1-6, and also demonstrate better room-temperature storage performance. Combining Examples 1-6 and Comparative Examples 2-6, it is evident that by leveraging the intrinsic thermal conductivity of alumina in graphene-coated alumina, and further utilizing the high specific surface area and surface silanol groups of silica, the thixotropic and mechanical properties of the colloid are improved, aiding in the construction of a thermally conductive network. Simultaneously, the active groups on the surface of graphene-coated alumina can interact with carboxyl-functionalized boron nitride, constructing a three-dimensional thermally conductive network and filling gaps in the thermally conductive pathways. This enhances thermal conductivity while further ensuring the adhesive's high strength and long-term storage stability. It exhibits excellent comprehensive properties such as heat resistance; the two-dimensional sheets of graphene and the nanoparticles of silica interweave to form a rigid-semi-rigid three-dimensional composite network framework, providing a basic mechanical support framework for the adhesive layer; the porous structure of carboxyl-functionalized boron nitride is uniformly dispersed in the gaps of this framework, and the carboxyl groups on its surface react with the epoxy groups of the self-made tackifier during the curing period, anchoring the composite filler in the network. On the one hand, the modulus is reduced through the compression and rebound of the porous structure, and on the other hand, the composite filler and the self-made tackifier limit the excessive slippage of molecular chains and avoid the modulus from being too low. This constructs a network structure that has both a certain rigid support and sufficient elastic deformation capacity, thereby precisely controlling the elastic modulus within the MEMS packaging stress range, achieving a low-modulus, high-elasticity mechanical property and a high-adhesion adhesive.

[0043] As can be seen from Example 1 and Comparative Example 1, the self-made tackifier introduces active functional groups such as epoxy groups and methacryloxy groups through silane hydrolysis condensation and titanate catalytic crosslinking. This matches the reactivity of the organosilicon matrix and the surface characteristics of the substrate, providing bonding sites and introducing flexible segments. Unlike the physical adsorption tackification of ordinary tackifiers, this improves the adhesion of the adhesive to inorganic surfaces such as chips and substrates, resulting in stronger adhesion and improved shear strength and heat resistance.

[0044] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A one-component thermosetting addition-curing silicone adhesive for chip packaging, characterized in that: The raw material components include the following parts by weight: 40-60 parts of electronic grade vinyl silicone oil, 5-15 parts of vinyl MQ silicone resin, 1-3 parts of color paste, 8-12 parts of special structure vinyl silicone oil, 3-8 parts of end-side hydrogen-containing silicone oil, 0.1-0.15 parts of platinum catalyst, 0.01-0.1 parts of inhibitor, 1-3 parts of self-made tackifier, and 35-75 parts of composite filler; the composite filler includes graphene-coated alumina, silica, and carboxyl-functionalized boron nitride.

2. The single-component thermosetting addition-curing silicone adhesive for chip packaging according to claim 1, characterized in that: The preparation method of the self-made tackifier includes: (1) taking dimethyl dimethoxysilane, methyl vinyl dimethoxysilane, 3-(2,3-epoxypropoxy)propyltrimethoxysilane, 3-(methacryloyloxy)propyltrimethoxysilane and tetraethyl orthosilicate in sequence and adding them to ethylene glycol, then stirring and adding resin catalyst and water to react, and then processing to obtain polysiloxane oligomer; (2) adding isopropanol solution containing tetrabutyl titanate, reacting at 60-80℃ for 2-4h, adding magnesium oxide, and rotary evaporating to obtain the self-made tackifier.

3. The single-component thermosetting addition-curing silicone adhesive for chip packaging according to claim 1, characterized in that: The preparation method of the carboxyl-functionalized boron nitride includes: (1) dissolving hexadecyltrimethylammonium bromide in a mixture of water and ethanol, adding tetraethyl orthosilicate and ammonia water and stirring to obtain SiO2 precursor, then adding boric acid and urea and grinding and mixing, and reacting at 800-1000℃ for 5-6 hours under an ammonia atmosphere to obtain boron nitride complex; (2) dispersing the boron nitride complex in toluene, adding carboxylsilane, and reacting for 10-12 hours to obtain carboxyl-functionalized boron nitride.

4. The single-component thermosetting addition-curing silicone adhesive for chip packaging according to claim 3, characterized in that: The mass ratio of the boron nitride complex to the carboxysilane is 1:(0.8-1).

5. The single-component thermosetting addition-curing silicone adhesive for chip packaging according to claim 1, characterized in that: The mass ratio of graphene-coated alumina, silica, and carboxyl-functionalized boron nitride is (5-8):(3-5):(2-4).

6. The single-component thermosetting addition-curing silicone adhesive for chip packaging according to claim 1, characterized in that: The inhibitor is one or more of ethynylcyclohexanol, methylbutynol, ethynyl tert-butanol, and phenylbutynol.

7. The method for preparing the single-component thermosetting addition-curing silicone adhesive for chip packaging according to any one of claims 1-6, characterized in that: The steps include: (1) adding electronic grade vinyl silicone oil, special structure vinyl silicone oil, vinyl MQ silicone resin, color paste, and composite filler in sequence, stirring and mixing, heating to 90-100℃, and vacuum dehydration to obtain the base adhesive; (2) adding inhibitor, self-made tackifier, and end-side hydrogen-containing silicone oil to the base adhesive, stirring and reacting, adding platinum catalyst, vacuum stirring and mixing, and vacuum degassing to obtain a single-component thermosetting addition-curing silicone adhesive for chip packaging.

8. The method for preparing the single-component thermosetting addition-curing silicone adhesive for chip packaging according to claim 7, characterized in that: The conditions for the stirring reaction in (2) are to stir for 20-30 minutes at a temperature of 10-20℃ and a speed of 15-200 rpm.

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