High-thermal-conductivity chip bottom filling adhesive, preparation method and application

Abstract

The invention belongs to the technical field of heat-conducting glue and chip manufacturing, and discloses a high-heat-conductivity chip bottom filling glue, a preparation method and application, and the high-heat-conductivity chip bottom filling glue is prepared from bisphenol F epoxy resin, an anhydride curing agent, an accelerant, spherical silica powder, a high-heat-conductivity filler, a coloring agent and a wetting agent. The key point is that through synchronous improvement of the components, the proportion and the size and the particle size of the heat-conducting filler, on one hand, the heat conductivity coefficient of the underfill adhesive can be remarkably increased, the glass transition temperature can be increased, and the fluidity, the viscosity and the high-temperature resistance of the adhesive can be considered; therefore, the packaging process of the high-power large-size chip can be met, the requirements of heat dissipation, low expansion, stable and reliable structure and the like after curing can be met, and powerful guarantee is provided for the heat dissipation performance and reliability of the large-size chip.

Description

Technical Field

[0001] The present invention relates to the technical fields of thermal conductive adhesives and chip manufacturing technology, and particularly relates to a high thermal conductive chip underfill, a preparation method and an application thereof. Background Art

[0002] The development of modern semiconductor technology is rapid, and the continuous expansion of chip area makes the heat dissipation problem increasingly prominent. According to the data of the International Semiconductor Industry Association, the increasing speed of chip area far exceeds the improvement speed of heat dissipation capacity, resulting in the increase of chip temperature, which in turn affects the performance and lifespan of the device. Therefore, heat dissipation has become the main bottleneck restricting the development of integrated circuit performance. Chip underfill, as an important electronic packaging material, is widely used for filling between chips and substrates, playing roles of mechanical support, stress buffering and heat conduction. However, traditional chip underfills usually use epoxy resin as the matrix, and their thermal conductivity is relatively low, making it difficult to meet the heat dissipation requirements of high-power chips. In addition, heat is generated during the operation of the chip, leading to the increase of material temperature. Therefore, the underfill needs to have a relatively high glass transition temperature (Tg) to ensure the mechanical properties and stability of the material at high temperatures.

[0003] In order to address the above challenges, researchers are committed to developing materials with high thermal conductivity, high temperature resistance and strong adhesion as chip underfills. In recent years, high thermal conductive insulating fillers such as boron nitride, silicon dioxide, diamond, etc. have gradually received extensive attention due to their excellent thermal conduction performance and chemical stability. However, how to efficiently apply these high thermal conductive fillers to chip packaging while taking into account the viscosity and high temperature resistance of the material is still a technical problem to be solved urgently.

[0004] For example, the high-efficiency high-temperature resistant thermal conductive underfill and its preparation method disclosed in CN201711069729.4 is a one-component epoxy resin adhesive, and its glass transition temperature is often lower than 130 °C and fluctuates greatly among various embodiments, being unstable. Therefore, it is also difficult to take into account the fluidity, viscosity and high temperature resistance of the material. Summary of the Invention

[0005] The purpose of the present invention is to provide, in view of the above deficiencies in the prior art, a high thermal conductive chip underfill, a preparation method and an application thereof. By adjusting the proportion of each component, especially the particle size and mass ratio of the high thermal conductive filler, the microstructure of the cured adhesive layer is changed, synchronously improving the thermal conductivity and glass transition temperature of the underfill to fully match the requirements of the chip preparation process and packaging structure, effectively improving the heat dissipation performance and structural stability of the chip, having a stable glass transition temperature above 130 °C, taking into account the fluidity, viscosity and high temperature resistance of the material to meet the packaging requirements of large-size integrated circuit chips, thereby solving the above technical problems.

[0006] To achieve the above object, the technical solution provided by the present invention is as follows: A high thermal conductivity chip underfill adhesive, which is made of the following components by mass percentage: 15-20% bisphenol F epoxy resin, 10-15% acid anhydride curing agent, 1-2% accelerator, 5-10% spherical silica powder, 50-60% high thermal conductivity filler, 0.1-0.2% colorant and 1-5% wetting agent; Among them, the structural formula of bisphenol F epoxy resin is: ; After the high thermal conductivity chip underfill adhesive is cured, the glass transition temperature is stable and not less than 135 °C, and at the same time the thermal conductivity is not less than 1.85 W·m -1 ·K -1 ; The epoxy equivalent of the bisphenol F epoxy resin is between 160-180 g / eq.

[0007] A method for preparing the high thermal conductivity chip underfill adhesive, characterized in that it comprises the following steps: S1: Prepare the first slurry: Add each component into the reaction kettle according to the set ratio, stir and react to mix evenly to obtain the first slurry. S2: Prepare the second slurry: Transfer the first slurry to a homogenizer for dispersion and homogenization treatment to obtain a dispersed second slurry; S3: Prepare the finished product: Vacuum degas the uniformly dispersed second slurry, discharge it from the kettle and seal it for packaging to obtain the finished product of the high thermal conductivity chip underfill adhesive.

[0008] Application of the high thermal conductivity chip underfill adhesive in the preparation of flip chips.

[0009] Compared with the prior art, the present invention has at least the following beneficial effects: 1. The high thermal conductivity chip underfill adhesive provided by the present invention focuses on synchronously improving the components, ratio, size and particle size of the thermal conductivity filler. On the one hand, it can significantly improve the thermal conductivity coefficient of the underfill adhesive, increase the glass transition temperature, and can take into account the fluidity, viscosity and high temperature resistance of the adhesive, so that it can meet the packaging process of high-power large-size chips and the requirements of heat dissipation, low expansion and stable structure after curing.

[0010] 2. The high thermal conductivity chip underfill adhesive provided by the present invention optimizes the type and dosage of the curing agent, ensuring that after curing, the underfill adhesive has a relatively dense microstructure and a high and stable glass transition temperature, thereby enabling the chip to maintain good mechanical properties and stability at high temperatures.

[0011] 3. The high thermal conductivity chip underfill adhesive and its application provided by the present invention make full use of the synergy between spherical silicon microparticles and other components to ensure the coefficient of thermal expansion of the underfill adhesive. At the same time, a wetting agent is used to improve the fluidity of the underfill adhesive, and a colorant is used for coloring; thus, the chip underfill adhesive has good fluidity, a high glass transition temperature, and high thermal conductivity. 4. The chip underfill adhesive and its application provided by the present invention have a simple and feasible preparation method, are suitable for large-scale industrial production, and can significantly improve the reliability and lifespan of chip packaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of embodiments in conjunction with the accompanying drawings, where: Figure 1 is a schematic flow chart of the high thermal conductivity chip underfill adhesive suitable for large-size chips prepared in the embodiment of the present invention; Figure 2 is a schematic structural diagram of a flip chip prepared in the embodiment of the present invention.

[0013] Figure 3 is a schematic diagram of the underfill process route when the present invention is applied to a flip chip.

[0014] In the figure: 1. Chip; 2. Solder bump; 3. Substrate; 4. Bottom contact metal; 5. Contact pad; 6. Passivation; 7. Solder mask; 8. Underfill adhesive. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The following further describes the present invention in detail in conjunction with the accompanying drawings and embodiments, so that those skilled in the art can implement it according to the description in the specification.

[0016] It should be understood that the terms such as "having", "comprising", and "including" used herein do not exclude the presence or addition of one or more other elements or their combinations.

[0017] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchases or can be prepared by existing methods.

[0018] Basic Embodiment The high thermal conductivity chip underfill glue provided by the embodiment of the present invention is made of the following components by mass percentage: 15-20% bisphenol F epoxy resin, 10-15% anhydride curing agent, 1-2% accelerator, 5-10% spherical silica powder, 50-65% high thermal conductivity filler, 0.1-0.2% colorant and 1-5% wetting agent; Among them, the structural formula of bisphenol F type epoxy resin is: ; After the high thermal conductivity chip underfill glue is cured, the glass transition temperature is stable and not less than 135 °C, and at the same time the thermal conductivity is not less than 1.85 W·m -1 ·K -1 .

[0019] The epoxy equivalent (EEW) of the bisphenol F type epoxy resin is between 160-180 g / eq, such as NPEF-170, EPON862, EPICLON 830, Araldite PY 302-2, etc.

[0020] The anhydride curing agent is at least one of phthalic anhydride, methyltetrahydrophthalic anhydride, and methylhexahydrophthalic anhydride; The accelerator is an imidazole type or amine type accelerator. The imidazole type accelerator is at least one of 2-butylimidazole and 2-ethyl-4-methylimidazole; the amine type accelerator is at least one of 2,4,6-tris(dimethylaminomethyl)phenol and o-hydroxybenzyl dimethylamine.

[0021] The average particle size of the spherical silica powder is 0.5-1 μm.

[0022] The high thermal conductivity filler is at least one of boron nitride, aluminum oxide (Al 2 O 3 ), diamond, magnesium oxide, zinc oxide, silicon dioxide, and silicon nitride, and the average particle size is 5-20 μm.

[0023] The colorant is carbon black; the wetting agent is EASYTECH ST-5100, and its structural formula is: .

[0024] A method for preparing the high thermal conductivity chip underfill glue includes the following steps: S1: Prepare the first slurry: Add each component into the reaction kettle according to the set ratio, stir and react to mix evenly to obtain the first slurry, S2: Prepare the second slurry: Transfer the first slurry to a homogenizer for dispersion and homogenization treatment to obtain a dispersed second slurry; S3: Preparation of finished product: The uniformly dispersed second slurry is degassed under vacuum, specifically under a vacuum degree of 0.01 - 0.1 MPa for 15 minutes of vacuum retention, and then taken out of the kettle and sealed for packaging to obtain a finished product of high - thermal - conductivity chip underfill adhesive.

[0025] Application of the high - thermal - conductivity chip underfill adhesive in the preparation of flip - chip.

[0026] The said application is to apply the high - thermal - conductivity chip underfill adhesive to the preparation of flip - chip, including the following steps: A1: Preparation of the body of the flip - chip Prepare the body of the flip - chip, which includes a substrate, a chip board arranged on one surface of the substrate, and a plurality of spaced - apart solder bumps located between the substrate and the chip board and electrically connected to the substrate and the chip board. There is a gap reserved between the substrate and the chip board; A2: Filling the colloid The high - thermal - conductivity chip underfill adhesive is filled into the gap reserved between the substrate and the chip board by pouring. Specifically, the filling adhesive is extruded to the edges of the substrate and the chip board through a syringe, and the filling adhesive flows from one end of the substrate and the chip board to the other end through capillary action until the entire gap is filled; A3: Heating and curing The whole flip - chip is heated and cured. The curing temperature is 120 °C and the curing time is not less than 1 h; after curing, the colloid encapsulates the substrate, the chip board and the solder bumps as a whole to obtain a flip - chip.

[0027] The size of the flip - chip is not less than 10 mm × 25 mm, and the gap between the chip board and the substrate is less than 30 μm.

[0028] In this embodiment, in the bisphenol F - type epoxy resin used, the distribution of benzene rings and hydroxyl groups makes it have a lower viscosity, which can better fill the micro - gaps in the chip gap and reduce the residual bubbles; the high - thermal - conductivity filler can significantly increase the thermal conductivity of the underfill adhesive through its high thermal conductivity, optimized heat conduction path, good dispersion characteristics and interfacial compatibility; the spherical silicon microparticles, as a filler with a low coefficient of thermal expansion, can effectively restrict the thermal movement of the matrix resin, disperse stress and filling effect, and significantly reduce the coefficient of thermal expansion of the underfill adhesive; the fluidity of the underfill adhesive is improved by adjusting the content of the wetting agent, and coloring is carried out using a colorant; the colorant is used to color the underfill adhesive to facilitate the identification of the chip.

[0029] The present application will be further described below in conjunction with specific embodiments. These embodiments are only used to illustrate the present application and not to limit the scope of the present application. For the experimental methods without specific conditions indicated in the following embodiments, they are generally determined in accordance with national standards. If there is no corresponding national standard, they are carried out in accordance with general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0030] Example 1 The high thermal conductivity chip underfill glue, preparation method and application provided by the embodiments of the present invention are specific embodiments based on the basic embodiments.

[0031] The high thermal conductivity chip underfill glue provided in this embodiment is prepared from the following components by mass percentage: 17% bisphenol F epoxy resin (NPEF-170), 14% acid anhydride curing agent (phthalic anhydride), 2% accelerator (2-butylimidazole), 10% spherical silica powder (average particle size of 0.5 μm), 54.8% filler boron nitride (average particle size of 5 μm), 0.2% carbon black as coloring agent, 2% wetting agent EASYTECH ST-5100; The preparation method of the high thermal conductivity chip underfill glue includes the following steps: S1: Add each component according to the above ratio to a reaction kettle, carry out stirring and mixing reaction, the stirring speed is 800 rpm, and the stirring time is 30 min to obtain a first slurry; S2: Transfer the first slurry to a homogenizer for dispersion treatment, the dispersion time is 20 min, and the rotation speed is 1500 rpm to obtain a dispersed second slurry; S3: Carry out vacuum degassing on the uniformly dispersed second slurry, the degassing time is 30 minutes, and the vacuum degree is -0.09 MPa, then take out of the kettle and seal and package to obtain the finished product of the high thermal conductivity chip underfill glue.

[0032] Then, the prepared high thermal conductivity chip underfill glue is extruded through a syringe and filled into the gap of the flip chip, and the filling glue fills the entire reserved gap inside the chip through capillary action.

[0033] Place the filled chip in an oven and cure it under the conditions of 120 °C for 2 h.

[0034] Example 2 The high thermal conductivity chip underfill glue, preparation method and application provided by the embodiments of the present invention are basically the same as those in Example 1, and the differences are as follows: The components for preparing the highly thermally conductive underfill adhesive for chips include, by mass percentage: 15% bisphenol F epoxy resin (EPON 862), 10% anhydride curing agent (methyltetrahydrophthalic anhydride), 1.5% accelerator (2,4,6-tris(dimethylaminomethyl)phenol), 5% spherical silica powder (average particle size 0.75 μm), 65% alumina (average particle size 10 μm) as the filler, 0.1% carbon black, and 3.4% wetting agent.

[0035] The embodiment of the present invention provides a method for preparing a highly thermally conductive underfill adhesive for chips, which includes the following steps: S1: Add each component into a reaction kettle according to the aforementioned ratio, carry out stirring and mixing reaction, with a stirring speed of 1000 rpm and a stirring time of 30 min to obtain a first slurry; S2: Transfer the first slurry to a homogenizer for dispersion treatment, with a dispersion time of 20 min and a rotation speed of 1500 rpm to obtain a second dispersed slurry; S3: Carry out vacuum degassing on the uniformly dispersed second slurry, with a degassing time of 30 minutes and a vacuum degree of -0.09 MPa, then take it out of the kettle and seal and package it to obtain the finished product of the highly thermally conductive underfill adhesive for chips.

[0036] Example 3 The highly thermally conductive underfill adhesive for chips, the preparation method and the application provided by the embodiment of the present invention are basically the same as those in Example 2, and the differences are as follows: The components for preparing the highly thermally conductive underfill adhesive for chips include, by mass percentage: 18.85% bisphenol F epoxy resin (EPICLON 830), 15% anhydride curing agent (methylhexahydrophthalic anhydride), 1% accelerator (2-ethyl-4-methylimidazole), 10% spherical silica powder (average particle size 1 μm), 50% silicon nitride (average particle size 20 μm), 0.15% carbon black, and 5% wetting agent.

[0037] The embodiment of the present invention provides a method for preparing a highly thermally conductive underfill adhesive for chips, which includes the following steps: S1: Add each component into a reaction kettle according to the above ratio, carry out stirring and mixing reaction, with a stirring speed of 1200 rpm and a stirring time of 30 min to obtain a first slurry, S2: Transfer the first slurry to a homogenizer for dispersion treatment, with a dispersion time of 20 min and a rotation speed of 1500 rpm to obtain a second dispersed slurry; S3: Carry out vacuum degassing on the uniformly dispersed second slurry, with a degassing time of 30 minutes and a vacuum degree of -0.09 MPa to obtain the underfill adhesive.

[0038] Example 4 The high thermal conductivity underfill adhesive for chips, preparation method and application provided by the embodiments of the present invention are basically the same as those in Embodiments 1 to 3, and the differences are as follows: The components for preparing the high thermal conductivity underfill adhesive for chips include, by mass percentage: 20% bisphenol F epoxy resin (NPEF-170), 11.5% anhydride curing agent (phthalic anhydride), 1% accelerator (o-hydroxybenzyl dimethylamine), 8.5% spherical silica powder (average particle size 1 μm), 57.3% silicon dioxide (average particle size 15 μm), 0.2% carbon black and 1.5% wetting agent.

[0039] Example 5 The high thermal conductivity underfill adhesive for chips, preparation method and application provided by the embodiments of the present invention are basically the same as those in Embodiment 1, and the differences are as follows: The components for preparing the high thermal conductivity underfill adhesive for chips include, by mass percentage: 17% bisphenol F epoxy resin (EPICLON 830), 14% anhydride curing agent (methylhexahydrophthalic anhydride), 1.5% accelerator (2-ethyl-4-methylimidazole), 5.9% spherical silica powder (average particle size 0.75 μm), 59% silicon nitride (average particle size 20 μm), 0.1% carbon black and 2.5% wetting agent.

[0040] The following is a test on the storage modulus, glass transition temperature, fluidity and thermal conductivity of the underfill adhesives provided in Embodiments 1-3. The specific test process is as follows: 1. Storage modulus: Reference standard: ASTM E2254-2018. Take samples cured completely at 120 °C for 2 h. The size of the test samples prepared is 25 mm × 10 mm × 2 mm. Measure using DMA. Vibration frequency: 1 Hz, amplitude: 20 μm, heating rate: 3 °C / min; The storage modulus takes the value from 25 °C to 160 °C.

[0041] 2. Glass transition temperature Tg: Take samples cured completely at 120 °C for 2 h. The size of the test samples prepared is 25 mm × 10 mm × 2 mm. Test the glass transition temperature (Tg) of the samples using DMA. DMA parameter settings: Vibration frequency: 1 Hz, amplitude: 20 μm, heating rate: 3 °C / min; Temperature: 25 °C - 160 °C.

[0042] 3. Liquidity test: A rectangular Si wafer with dimensions of 20 mm × 40 mm and a thickness of 0.5 mm is adhered to the substrate by sticking its four corners with a 50-μm-thick double-sided adhesive. The bottom filling adhesive to be tested is dispensed horizontally along one side of the rectangular Si wafer (30 - 35 mg) using a dispensing machine. It is placed on a hot plate at 90 °C and the timing starts simultaneously. Under the action of capillary force, the bottom filling adhesive will flow along the bottom of the Si wafer. Record the time when it flows to half of the Si wafer and the time when it is fully filled.

[0043] 4. Thermal conductivity test: The laser flash method (LFA) is used to measure the thermal conductivity of the bottom filling adhesive. Samples cured completely at 120 °C for 2 h are taken, and the dimensions of the test samples are 10 mm × 10 mm × 2 mm.

[0044] The test results are shown in Table 2 below.

[0045] Table 2

[0046] As can be seen from Table 2 above: (1) In the embodiments of the present invention, high thermal conductivity fillers within a specific particle size range (such as boron nitride, alumina, silicon nitride) are used, significantly improving the thermal conductivity of the bottom filling adhesive. Especially when boron nitride is used as the high thermal conductivity filler, it exhibits a relatively high thermal conductivity (2.19 W·m -1 ·K -1 ). The high thermal conductivity fillers significantly improve the thermal conductivity of the underfill adhesive through their high thermal conductivity, optimized heat conduction paths, good dispersion, and interfacial compatibility. Among them, the type, morphology, size, surface treatment method, and filling amount of the high thermal conductivity fillers are all key factors affecting the thermal conductivity; through the synergy of the fillers and other components, a dense microstructure of the cured composite material can be reasonably designed to further optimize its thermal conductivity and meet the heat dissipation requirements of high-power chips.

[0047] (2) By adding wetting agents in the above-mentioned embodiments, the liquidity of the bottom filling adhesive is improved, ensuring complete filling of the chip gap. High thermal conductivity fillers usually have a high surface energy and are prone to agglomeration in an organic matrix (such as epoxy resin), resulting in uneven dispersion. The wetting agent molecules have an amphiphilic structure, with a hydrophilic group (such as a hydroxyl group, carboxyl group, etc.) at one end and a hydrophobic group (such as a hydrocarbon chain) at the other end. This structure enables the wetting agent to adsorb on the surface of the filler, reducing the surface tension between the filler and the matrix, thereby reducing the interaction force between the filler particles and preventing agglomeration. In addition, by reducing the viscosity, enhancing the capillary action, and improving the filling efficiency, it is ensured that the filling adhesive can quickly and evenly fill the chip gap.

[0048] (3) Through the above experimental verification, the technical solutions in the claims have high feasibility and superiority, and can effectively improve the comprehensive performance of the underfill adhesive for flip chips.

[0049] The above five embodiments respectively show the performance of the high thermal conductivity underfill adhesive for chips of the present invention under different formulations and process conditions. Through reasonable design of the formulation and process, the present invention successfully develops a high thermal conductivity underfill adhesive suitable for large-sized chips. The high thermal conductivity underfill adhesives (hereinafter referred to as underfill) provided in each embodiment of the present invention adopt components such as bisphenol F epoxy resin, and by adjusting the particle size and mass ratio of the high thermal conductivity fillers, the thermal conductivity and glass transition temperature of the underfill are changed; by adjusting the content of the wetting agent to control the rheological properties of the underfill, the underfill adhesives provided by the present invention have the characteristics of high fluidity, high glass transition temperature and high thermal conductivity coefficient, etc., providing a strong guarantee for the heat dissipation performance and reliability after the packaging of large-sized chips.

[0050] It should be particularly pointed out that within the scope of the components, ratios and process parameters recorded in the present invention, other technical solutions obtained by specific selection can all achieve the technical effects of the present invention, so they will not be listed one by one. The above actual tests show that the filling adhesive exhibits excellent performance in terms of thermal conductivity, high-temperature stability and fluidity, and can effectively improve the reliability and lifespan of chip packaging. The application of the present invention also provides a reliable material solution for the heat dissipation and packaging of high-power chips, and has broad application prospects. These embodiments further prove the feasibility and superiority of the present invention, and provide a reliable material solution for the heat dissipation and packaging of high-power chips.

[0051] Other technical solutions obtained by adopting components, ratios, preparation methods and applications equivalent to those recorded in the present invention are all included in the protection scope of the present invention.

[0052] The above are only the preferred embodiments of the present invention, and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A high thermal conductivity chip bottom filling glue, characterized in that: The invention is made of the following components by mass percentage: 15-20% bisphenol F epoxy resin, 10-15% acid anhydride curing agent, 1-2% accelerator, 5-10% spherical silica powder, 50-65% high thermal conductive filler, 0.1-0.2% colorant and 1-5% wetting agent; Among them, the structural formula of bisphenol F epoxy resin is: ； After the high thermal conductivity chip bottom filling glue is cured, the glass transition temperature is stable and not less than 135°C, and the thermal conductivity is not less than 1.85 W·m -1 ·K -1 .

2. The high thermal conductivity chip bottom filling glue according to claim 1, characterized in that: The epoxy equivalent of the bisphenol F epoxy resin is between 160 and 180 g / eq.

3. The high thermal conductivity chip bottom filling glue according to claim 1, characterized in that: The acid anhydride curing agent is at least one of phthalic anhydride, methyltetrahydrophthalic anhydride and methylhexahydrophthalic anhydride; The accelerator is an imidazole or amine accelerator, the imidazole accelerator is at least one of 2-butylimidazole and 2-ethyl-4-methylimidazole; the amine accelerator is at least one of 2,4,6-tris(dimethylaminomethyl)phenol and o-hydroxybenzyldimethylamine.

4. The high thermal conductivity chip bottom filling glue according to claim 1, characterized in that: The spherical silicon powder has an average particle size of 0.5-1 μm.

5. The high thermal conductivity chip bottom filling glue according to claim 1, characterized in that: The high thermal conductivity filler is at least one of boron nitride, aluminum oxide, diamond, magnesium oxide, zinc oxide, silicon dioxide and silicon nitride, and has an average particle size of 5-20 μm.

6. The high thermal conductivity chip bottom filling glue according to claim 1, characterized in that: The colorant is carbon black; the wetting agent is EASYTECH ST-5100, and its structural formula is: 。 7. A method for preparing the high thermal conductivity chip bottom filling glue according to any one of claims 1 to 6, characterized in that: It includes the following steps: S1: Preparation of the first slurry: Add each component into the reactor according to the set ratio, stir to react and mix evenly to obtain the first slurry. S2: Preparation of the second slurry: The first slurry is transferred to a homogenizer for dispersion and homogenization to obtain a dispersed second slurry; S3: Preparation of finished product: The evenly dispersed second slurry is vacuum degassed, taken out of the kettle and sealed and packaged to obtain a finished product of a chip bottom filling adhesive with high thermal conductivity.

8. Use of the high thermal conductive chip bottom filling glue according to any one of claims 1 to 6 in the preparation of flip chips.

9. The use according to claim 8, characterized in that: The high thermal conductivity chip bottom filling glue is applied to prepare a flip chip, comprising the following steps: A1: Preparation of flip chip body Prepare a flip chip body, which includes a substrate, a chip board arranged on a surface of the substrate, and a plurality of solder bumps arranged at intervals between the substrate and the chip board and electrically connected to the substrate and the chip board, wherein a gap is reserved between the substrate and the chip board; A2: Filling colloid Filling the chip bottom filling glue with high thermal conductivity into the reserved gap between the substrate and the chip board, specifically, squeezing the filling glue to the edge of the substrate and the chip board through a needle tube, and the filling glue flows from one end of the substrate and the chip board to the other end through capillary action until the entire gap is filled; A3: Heating and curing The flip chip is heated and cured as a whole, the curing temperature is 120° C., and the curing time is not less than 1 hour; after the curing is completed, the colloid encapsulates the substrate, the chip board and the welding bumps as a whole to obtain the flip chip.

10. The use according to claim 9, characterized in that: The size of the flip chip is not less than 10 mm×25 mm, and the gap between the chip board and the substrate is less than 30 μm.

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