High-thermal-conductivity and high-filling-density elargol, preparation method thereof and application of elargol in semiconductor packaging

Abstract

The invention relates to the field of sealant materials, in particular to a high-thermal-conductivity and high-filling-density elargol and a preparation method thereof. The high-thermal-conductivity and high-filling-density elargol is prepared from the following raw materials: silver particles, carrier resin, a curing agent, a coupling agent, a diluent, a defoaming agent, a flatting agent, a polymer additive and the like. The high-thermal-conductivity and high-filling elargol prepared by the invention has the most remarkable beneficial effects that the contradiction between high silver content and excellent processability is successfully solved, excellent balance of comprehensive performance is realized, and the high-thermal-conductivity and high-filling elargol can show good flowability and silk-screen printing trafficability in a dispensing or printing process; the problems of sagging, wire flying or hole blocking and the like are effectively avoided, and the processing efficiency and the yield of a semiconductor packaging process are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of packaging materials, more particularly to a silver adhesive with high thermal conductivity and high filling density, a preparation method thereof and application in semiconductor packaging. BACKGROUND

[0002] In the field of semiconductor packaging, with the continuous increase of chip power density and the continuous miniaturization of device size, efficient heat dissipation has become a key factor to ensure device reliability and prolong service life. As the key interface material between the chip and the substrate or heat sink, the thermal conductive adhesive, especially the silver adhesive, is widely used due to its excellent electrical conductivity and thermal conductivity. Its core role is to fill the small gap between the chip and the heat dissipation structure, exclude air, and establish an efficient heat conduction path to quickly conduct the heat generated by the chip during operation, thereby maintaining the junction temperature within a safe range.

[0003] At present, the widely used conventional silver adhesive is mainly composed of organic polymers such as epoxy resin and acrylate as the matrix, and filled with a large amount of micron or nanoscale silver powder. Its heat conduction mechanism mainly depends on the heat conduction network formed by the mutual contact of silver powder in the organic matrix. In order to obtain higher thermal conductivity, the common technical path is to continuously increase the filling density of silver powder, i.e. the volume or weight percentage of silver powder in the adhesive. In the prior art, the filling density of silver adhesive with high silver content can usually reach 85% to 90% by weight, or even higher, in order to maximize the content of metal fillers to approach the high thermal conductivity of silver itself.

[0004] However, with the significant increase of silver powder filling density, a series of technical and process challenges also come with it. First, the extremely high silver powder content will sharply increase the viscosity of the silver adhesive, leading to deterioration of its rheological properties, poor flowability, printability or dispensing properties. This makes it difficult to achieve ultra-thin, uniform and defect-free adhesive layer coating in the packaging process, especially when facing advanced packaging designs with complex three-dimensional structures or extremely small gaps, the problem of insufficient filling and covering ability is more prominent. Second, during the curing process, it is more difficult for the gas or solvent wrapped in the high-viscosity silver adhesive to be discharged, and internal micropores or interface delamination defects are easily formed. These defects not only interrupt the local heat conduction path, actually reducing the overall heat conduction efficiency, but also become a weak point of the mechanical structure, affecting the mechanical strength and long-term thermal cycle reliability of the packaging. SUMMARY

[0005] In summary, the prior art simply pursues high silver filling density to improve the thermal conductivity, which inevitably reduces the comprehensive application performance and processing operability of the silver paste, and ultimately affects the overall performance of the semiconductor product. Therefore, how to realize the stable improvement of the thermal conductivity of the silver paste without sacrificing or even improving the application performance of the silver paste, such as flowability, dispensing, covering effect and processing performance, has become a technical problem to be solved in the field.

[0006] A high-thermal-conductivity high-filling-density silver paste, by mass fraction, raw materials include: silver particles 330-370 parts, carrier resin 20-35 parts, curing agent 3-6 parts, coupling agent 1-2 parts, diluent 2-3 parts, defoaming agent 0.2-0.4 parts, leveling agent 0.3-0.5 parts, thixotropic agent 0.3-0.8 parts, wetting and dispersing agent 1-1.8 parts, polymer additive 4-12 parts.

[0007] Preferably, the silver particles are a combination of micron silver particles and nano silver particles.

[0008] Preferably, the mass ratio of the micron silver particles and the nano silver particles is (8-10):(2-4).

[0009] Preferably, the mass ratio of the micron silver particles and the nano silver particles is (9-10):(2-3).

[0010] Preferably, the micron silver particles are spherical micron silver particles with an average particle size of 1-10 μm.

[0011] Preferably, the average particle size of the spherical micron silver particles is 2.5-5 μm.

[0012] Preferably, the nano silver particles are spherical nano silver particles with an average particle size of 50-150 nm.

[0013] Preferably, the average particle size of the spherical nano silver particles is 60-100 nm.

[0014] Preferably, the mass ratio of the silver particles, the carrier resin and the polymer additive is (34-36.5):(2.2-3):(0.6-1).

[0015] Preferably, the mass ratio of the silver particles, the carrier resin and the polymer additive is (35-36):(2.4-2.7):(0.7-0.9).

[0016] Preferably, the carrier resin is a combination of flexible polyurethane epoxy resin and phenolic epoxy resin.

[0017] Preferably, the mass ratio of the flexible polyurethane epoxy resin and the phenolic epoxy resin is (2-3):(0.8-1.2).

[0018] Preferably, the mass ratio of the flexible polyurethane epoxy resin to the phenolic epoxy resin is (2.3~2.5):(1~1.1).

[0019] Preferably, the epoxy value of the phenolic epoxy resin is 190~230 g / eq.

[0020] Preferably, the epoxy value of the flexible polyurethane epoxy resin is 300~350 g / eq.

[0021] Preferably, the flexible polyurethane epoxy resin is specifically flexible polyurethane epoxy resin DER852, manufactured by Dow Chemical Company, USA.

[0022] Preferably, the phenolic epoxy resin is o-cresol epoxy resin NPPN 631, manufactured by Nan Ya Plastics, Taiwan.

[0023] The carrier resin added in this application fundamentally optimizes the processing rheology and interfacial bonding effect of the silver paste while ensuring the final performance. The compounded raw materials use a flexible polyurethane epoxy long-chain molecular structure to isolate and lubricate the high-density stacked silver particles, and significantly reduce the viscosity of the system under shear force, giving the silver paste excellent flowability and dispensing / filamentation ability.

[0024] On the other hand, the combined effect of the two enhances the toughness of the cured silver paste, alleviates the internal stress caused by thermal expansion mismatch, improves its coverage and wrapping effect on the chip and substrate, and provides high cross-linking density during curing, ensuring the overall heat resistance, modulus and bonding strength of the silver paste, and preventing performance degradation due to excessive toughening. The combination of the two achieves the performance balance of the high-filler silver paste throughout the entire life cycle from processing to service.

[0025] Preferably, the curing agent is at least one selected from methyltetrahydrophthalic anhydride, polyetheramine, methylhexahydrophthalic anhydride, and diaminodiphenyl sulfone.

[0026] Preferably, the curing agent is methyltetrahydrophthalic anhydride or diaminodiphenyl sulfone.

[0027] Preferably, the curing agent is methyltetrahydrophthalic anhydride.

[0028] Preferably, the coupling agent is at least one selected from γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and vinyltrimethoxysilane.

[0029] Preferably, the coupling agent is γ-aminopropyltriethoxysilane or vinyltrimethoxysilane.

[0030] Preferably, the coupling agent is γ-aminopropyltriethoxysilane.

[0031] Preferably, the diluent is any one of benzyl alcohol, octyl glycidyl ether, and 1,4-butanediol diglycidyl ether.

[0032] Preferably, the diluent is benzyl alcohol or octyl glycidyl ether.

[0033] Preferably, the defoamer is at least one of silicone defoamers.

[0034] Preferably, the leveling agent is at least one of polyether-modified polydimethylsiloxane, polyacrylate, fluorocarbon-modified polymer, and cellulose acetate butyrate.

[0035] Preferably, the leveling agent is polyether-modified polydimethylsiloxane or polyacrylate.

[0036] Preferably, the leveling agent is polyacrylate.

[0037] Preferably, the thixotropic agent is at least one of fumed silica, hydrogenated castor oil, polyamide wax, and organobentonite.

[0038] Preferably, the thixotropic agent is fumed silica or hydrogenated castor oil.

[0039] Preferably, the thixotropic agent is hydrogenated castor oil.

[0040] Preferably, the wetting and dispersing agent is at least one selected from phosphate esters, polyurethanes, and acrylics.

[0041] Preferably, the wetting and dispersing agent is a phosphate ester or a polyurethane.

[0042] Preferably, the wetting and dispersing agent is a phosphate ester.

[0043] Preferably, the polymer additive is a combination of epoxy acrylate and polyurethane acrylate oligomers.

[0044] Preferably, the mass ratio of the epoxy acrylate to the polyurethane acrylate oligomer is (2.5~3.5):(0.8~1.3).

[0045] Preferably, the mass ratio of the epoxy acrylate to the polyurethane acrylate oligomer is (2.6~3):(1~1.2).

[0046] Preferably, the polyurethane acrylate oligomer is CN9006, produced by Sartoma, France.

[0047] Preferably, the epoxy acrylate is EBECRYL 3740, manufactured by Zyxel from the Netherlands.

[0048] The added polymer additives create a high-performance internal network system for the silver paste during high-speed dispensing and low-temperature soldering, achieving a good balance between flowability and final mechanical strength. The combination of these two additives provides high molecular rigidity, and their long, flexible chain segments act as internal plasticizers, effectively reducing system viscosity and improving the flow uniformity and dispensing stability of the colloid, avoiding poor flowability and uniformity at high viscosity. Furthermore, during actual use and curing, it ensures strong adhesion to the substrate, guaranteeing excellent mechanical strength and heat resistance at the joints. The elastic network's toughness absorbs and disperses internal stress caused by mismatched coefficients of thermal expansion, preventing cracking of the adhesive layer. Together, these factors ensure the long-term structural integrity and reliability of the silver paste under complex working conditions.

[0049] A method for preparing a high thermal conductivity and high filling density silver paste includes the following steps: S1: Silver particles, carrier resin, polymerization aid, curing agent, thixotropic agent, and wetting and dispersing agent are added to a planetary mixer at once and mixed at 500-600 rpm for 15-20 min to obtain a preliminary mixture; S2: The remaining raw materials are added to the preliminary mixture and dispersed at 1200-1400 rpm for 30-40 min, and then passed through a three-roll mill 4-5 times to obtain a final mixture; S3: The final mixture is transferred to a vacuum desulfurization system. Degas the product using a foaming machine, then dispense it into containers and freeze it at -20~-10℃ to obtain the silver paste to be cured; S4: Apply or print the silver paste to be cured onto the component to be packaged, and then perform step-by-step temperature curing. First, pre-cur it at 75~85℃ for 30~60min, then raise the temperature to 145~150℃ for 90~120min, and then raise the temperature to 180~185℃ for 30~60min, maintaining a temperature increase rate of 2~3℃ / min during the process. After curing, the product is obtained.

[0050] This application further defines the application of the obtained high thermal conductivity and high filler density silver paste in semiconductor packaging.

[0051] The beneficial effects of this application are: 1. The most significant advantage of the high thermal conductivity and high filler silver paste prepared in this application is that it successfully solves the contradiction between high silver content and excellent processability, achieving an excellent balance of comprehensive performance. It can exhibit good flowability and screen printing passability during packaging or printing, effectively avoiding problems such as sagging, wire flying or hole blockage, greatly improving the processing efficiency and yield of semiconductor packaging process, ensuring high reliability and long life of packaging structure in long-term thermal cycling operation, and meeting the higher performance requirements of the current semiconductor field for this type of silver paste.

[0052] 2. The two raw materials in the composite carrier resin added in this application work together to enhance the toughness of the cured silver paste, alleviate the internal stress caused by thermal expansion mismatch, improve its coverage and wrapping effect on the chip and substrate, and provide high cross-linking density during curing, ensuring the overall heat resistance, modulus and bonding strength of the silver paste, and preventing performance degradation due to excessive toughening. The combination of the two achieves the performance balance of the high-filled silver paste throughout the entire life cycle from processing to service.

[0053] 3. The polymer additives further added in this application provide high molecular rigidity and, with their long flexible chain segments, act as internal plasticizers, effectively reducing the viscosity of the system and improving the flow uniformity and dispensing stability of the colloid, thus avoiding the phenomenon of poor flowability and uniformity at high viscosity. On the other hand, during the actual use and curing process, they achieve strong adhesion to the substrate, ensuring that the connection points have excellent mechanical strength and heat resistance, thereby providing a solid foundation for improving the overall performance of the silver paste. Detailed Implementation

[0054] Example 1

[0055] A high thermal conductivity and high filling density silver paste, by weight, comprises the following raw materials: 355 parts silver particles, 25 parts carrier resin, 4.5 parts curing agent, 1.3 parts coupling agent, 2.6 parts diluent, 0.3 parts defoamer, 0.4 parts leveling agent, 0.7 parts thixotropic agent, 1.4 parts wetting and dispersing agent, and 8.2 parts polymer additives.

[0056] The silver particles are a combination of micron-sized silver particles and nano-sized silver particles in a mass ratio of 10:2. The micron-sized silver particles are spherical with an average particle size of 3.2 μm; the nano-sized silver particles are spherical with an average particle size of 80 nm.

[0057] The carrier resin is a combination of flexible polyurethane epoxy resin and phenolic epoxy resin in a mass ratio of 2.5:1. The phenolic epoxy resin is o-cresol epoxy resin NPPN 631 with an epoxy value of 210 g / eq, manufactured by Nan Ya Plastics, Taiwan; the flexible polyurethane epoxy resin is specifically flexible polyurethane epoxy resin DER852 with an epoxy value of 320 g / eq, manufactured by Dow Chemical, USA.

[0058] The polymer additive is a combination of epoxy acrylate and polyurethane acrylate oligomers in a mass ratio of 2.8:1.2. The polyurethane acrylate oligomer is CN9006, produced by Sartoma, France; the epoxy acrylate is EBECRYL 3740, produced by Zinxin, Netherlands.

[0059] The curing agent is methyltetrahydrophthalic anhydride; the coupling agent is γ-aminopropyltriethoxysilane; the diluent is benzyl alcohol; the defoamer is BYK-024; the leveling agent is polyacrylate BYK-381; the thixotropic agent is hydrogenated castor oil; and the wetting and dispersing agent is phosphate ester TEGO 655.

[0060] A method for preparing a high thermal conductivity and high filling density silver paste includes the following steps: S1: Silver particles, carrier resin, polymer additives, curing agent, thixotropic agent, and wetting and dispersing agent are added to a planetary mixer at once and mixed at 600 rpm for 20 min to obtain a preliminary mixture; S2: The remaining raw materials are added to the preliminary mixture and dispersed at 1200 rpm for 38 min, and then passed through a three-roll mill 5 times to obtain a final mixture; S3: The final mixture is transferred to a vacuum degassing machine for degassing, and after degassing, it is packaged into containers and frozen at -15℃ to obtain the silver paste to be cured; S4: The silver paste to be cured is coated or printed onto the component to be packaged, and then subjected to step-by-step temperature curing. First, it is pre-cured at 80℃ for 50 min, then heated to 150℃ for 100 min, and then heated to 180℃ for 45 min, with the heating rate maintained at 2.5℃ / min. After curing, the final product is obtained.

[0061] Example 2

[0062] This embodiment differs from Embodiment 1 only in the following aspects: A high thermal conductivity and high filling density silver paste, by weight, comprises the following raw materials: 365 parts silver particles, 22 parts carrier resin, 4.5 parts curing agent, 1.3 parts coupling agent, 2.6 parts diluent, 0.3 parts defoamer, 0.4 parts leveling agent, 0.7 parts thixotropic agent, 1.4 parts wetting and dispersing agent, and 9.5 parts polymer additives.

[0063] The remaining implementation methods are the same.

[0064] Example 3

[0065] This embodiment differs from Embodiment 1 only in the following aspects: A silver paste with high thermal conductivity and high filling density, by weight, comprises the following raw materials: 360 parts silver particles, 29.5 parts carrier resin, 4.5 parts curing agent, 1.3 parts coupling agent, 2.6 parts diluent, 0.3 parts defoamer, 0.4 parts leveling agent, 0.7 parts thixotropic agent, 1.4 parts wetting and dispersing agent, and 7.5 parts polymer additives.

[0066] The remaining implementation methods are the same.

[0067] Comparative Example 1 This comparative example differs from Example 1 only in the following aspects: a silver paste with high thermal conductivity and high filling density, comprising, by weight, 395 parts silver particles, 29 parts carrier resin, 4.5 parts curing agent, 1.3 parts coupling agent, 2.6 parts diluent, 0.3 parts defoamer, 0.4 parts leveling agent, 0.7 parts thixotropic agent, 1.4 parts wetting and dispersing agent, and 2.2 parts polymer additives.

[0068] The remaining implementation methods are the same.

[0069] Comparative Example 2 This comparative example differs from Example 1 only in the following aspects: a silver paste with high thermal conductivity and high filling density, comprising, by weight, 360 parts silver particles, 15 parts carrier resin, 4.5 parts curing agent, 1.3 parts coupling agent, 2.6 parts diluent, 0.3 parts defoamer, 0.4 parts leveling agent, 0.7 parts thixotropic agent, 1.4 parts wetting and dispersing agent, and 12 parts polymer additives.

[0070] The remaining implementation methods are the same.

[0071] Comparative Example 3 This comparative example differs from Example 1 only in the following way: the carrier resin is a combination of flexible polyurethane epoxy resin and phenolic epoxy resin in a mass ratio of 3.3:0.2.

[0072] The remaining implementation methods are the same.

[0073] Comparative Example 4 The only difference between this comparative example and Example 1 is that the carrier resin is a combination of flexible polyurethane epoxy resin and phenolic epoxy resin in a mass ratio of 1.5:2.

[0074] The remaining implementation methods are the same.

[0075] Comparative Example 5 This comparative example differs from Example 1 only in the following way: the polymer additive is a combination of epoxy acrylate and polyurethane acrylate oligomers in a mass ratio of 3.5:0.5.

[0076] The remaining implementation methods are the same.

[0077] Comparative Example 6 This comparative example differs from Example 1 only in the following way: the polymer additive is a combination of epoxy acrylate and polyurethane acrylate oligomers in a mass ratio of 1:3.

[0078] The remaining implementation methods are the same.

[0079] Performance testing 1. Thermal conductivity: Refer to ASTM D5470, and the results are the average of 10 tests and recorded in Table 1.

[0080] 2. Resistivity: Refer to ASTM D257, and the results are the average of 10 tests recorded in Table 1.

[0081] 3. Degree and Rheological Properties: Using a rotational rheometer equipped with a cone-plate measurement system, uncured examples and comparative samples were placed on the measurement platform and tested under a constant temperature of 25°C. First, a shear rate scan was performed from 0.1 1 / s to 100 1 / s. Then, at a fixed high shear rate of 10 1 / s, the dispensing process was simulated, and at a low shear rate of 0.5 1 / s, the static state was simulated, and the apparent viscosity values ​​were read. The results were the average of 10 tests and recorded in Table 1.

[0082] 4. Shear strength: The silver paste prepared in the examples and comparative examples was applied to a standard silver-plated frame, and then a chip of a specified size (2mm×2mm) was attached. After curing, a push-pull force gauge was used to push the side of the chip at 0.5mm / s until the bonding joint failed. The maximum failure force was recorded to obtain the shear strength. The average value of 10 tests was recorded in Table 1.

[0083] 5. Thermal cycling stability: The test sample with the chip attached by silver paste was placed in a high and low temperature cycling test chamber. The thermal cycling temperature conditions were set from -30℃ to 150℃, and the temperature was maintained at the two extreme temperatures for 15 minutes. The heating rate was 10℃ / min, and 1000 cycles were performed. The shear strength retention rate of the sample after cycling was recorded. The test method was the same as that in performance test 4. The average value of 10 tests was recorded in Table 1.

[0084] Table 1 Performance Test Results Example Thermal conductivity (W / (m-K)) Electrical resistivity (μΩ-cm) Low shear viscosity (Pa-s) High shear viscosity (Pa-s) Shear strength (MPa) Thermal cycle-shear strength retention (%) Example 1 23.2 28.2 45.2 12.4 44.2 93.7 Example 2 22.9 29.7 44.7 11.9 43.9 93.6 Example 3 23.0 28.8 45.3 12.8 44.3 93.3 Comparative Example 1 20.9 31.7 41.6 15.9 38.9 90.9 Comparative Example 2 21.6 33.5 43.2 15.8 40.2 88.2 Comparative Example 3 22.1 32.0 42.9 14.2 41.5 91.4 Comparative Example 4 21.3 31.8 44.1 13.3 43.1 90.9 Comparative Example 5 21.7 32.2 43.4 13.6 42.6 92.3 Comparative Example 6 22.0 31.6 43.0 42.8 42.0 91.1 Examples 1-3 achieved better performance test results compared to Comparative Examples 1-6. This is mainly because the two raw materials in the compound carrier resin added in the technical solution specified in this application, used in Examples 1-3, work together to enhance the toughness of the cured silver paste, alleviate the internal stress caused by thermal expansion mismatch, improve its coverage and wrapping effect on the chip and substrate, and provide high crosslinking density during curing. This ensures the overall heat resistance, modulus, and adhesive strength of the silver paste, preventing performance degradation due to excessive toughening. Furthermore, the added polymer additives provide high molecular rigidity and, with their long flexible chain segments, act as internal plasticizers, effectively reducing the viscosity of the system and improving the flow uniformity and dispensing stability of the colloid, avoiding the phenomenon of poor flowability and uniformity at high viscosity. In contrast, Comparative Examples 1-6, because they adopted technical solutions different from those specified in this application, had significantly reduced technical effects in the silver paste system of this application, ultimately leading to a decrease in the overall performance of the silver paste.

Claims

1. A high thermal conductive high packing density silver paste, characterized in that: The raw materials include, in mass parts, silver particles 330-370 parts, carrier resin 20-35 parts, curing agent 3-6 parts, coupling agent 1-2 parts, diluent 2-3 parts, defoaming agent 0.2-0.4 parts, leveling agent 0.3-0.5 parts, thixotropic agent 0.3-0.8 parts, wet dispersing agent 1-1.8 parts, and polymer additive 4-12 parts; The silver particles are a combination of micron silver particles and nano silver particles, with a mass ratio of (8-10):(2-4); The carrier resin is a combination of flexible polyurethane epoxy resin and phenolic epoxy resin, with a mass ratio of (2-3):(0.8-1.2).

2. The high thermal conductive high packing density silver paste according to claim 1, characterized in that: The micron silver particles are spherical micron silver particles with an average particle size of 1-10 μm.

3. The high thermal conductive high packing density silver paste according to claim 2, characterized in that: The nano silver particles are spherical nano silver particles with an average particle size of 50-150 nm.

4. The high thermal conductive high packing density silver paste according to claim 3, characterized in that: The mass ratio of the silver particles, carrier resin and polymer additive is (34-36.5):(2.2-3):(0.6-1).

5. The high thermal conductive high packing density silver paste according to claim 4, characterized in that: The phenolic epoxy resin has an epoxy value of 190-230 g / eq, and the flexible polyurethane epoxy resin has an epoxy value of 300-350 g / eq.

6. The high thermal conductivity and high packing density silver paste according to claim 5, characterized in that: The flexible polyurethane epoxy resin is specifically flexible polyurethane epoxy resin DER852, and the phenolic epoxy resin is ortho-cresol formaldehyde epoxy resin NPPN631.

7. The high thermal conductivity and high packing density silver paste according to claim 6, characterized in that: The curing agent is at least one of methyl tetrahydrophthalic anhydride, polyether amine, methyl hexahydrophthalic anhydride and diaminodiphenyl sulfone.

8. The high thermal conductivity and high packing density silver paste according to claim 7, characterized in that: The polymer additive is a combination of epoxy acrylate and polyurethane acrylate oligomer, with a mass ratio of (2.5-3.5):(0.8-1.3).

9. A method for preparing the high thermal conductive and high packing density silver paste according to any one of claims 1-8, characterized in that: Specifically comprising the following steps: S1: the silver particles, carrier resin, polymer additive, curing agent, thixotropic agent and wet dispersing agent are added into a planetary mixer at one time, mixed at 500-600 rpm for 15-20 min to obtain a preliminary mixture; S2: the remaining raw materials are added to the preliminary mixture, dispersed at 1200-1400 rpm for 30-40 min, and passed through a three-roll mill 4-5 times to obtain a mixture; S3: the mixture is transferred to a vacuum defoaming machine for defoaming, and after defoaming, the mixture is divided into containers, frozen and stored at -20 to -10℃ to obtain a silver paste to be cured; S4: the silver paste to be cured is coated or printed on a component to be packaged, and then subjected to stepwise temperature curing, first pre-cured at 75-85℃ for 30-60 min, then cured at 145-150℃ for 90-120 min, and then cured at 180-185℃ for 30-60 min, with a temperature increasing rate of 2-3℃ / min during the process, to obtain the silver paste.

10. Use of the silver paste with high thermal conductivity and high filling density according to any one of claims 1-8 in semiconductor packaging.