A high-Tg, low-dielectric epoxy resin composition, its preparation method, and its application.

Abstract

This invention relates to the field of electronic device packaging materials technology, and particularly to a high Tg, low dielectric epoxy resin composition, its preparation method, and its applications. By weight, the epoxy resin composition comprises 35-70 parts of multifunctional epoxy resin, 10-20 parts of fluorinated epoxy resin, 10-15 parts of a low-stress agent, 0.2-5 parts of an adhesion promoter, 2-4 parts of a release agent, 500-1000 parts of filler, 0.2-1 parts of a catalyst, and 35-50 parts of a curing agent. The epoxy resin composition has a Tg above 250°C and a Dk below 10 under testing conditions of 200°C and 0.1Hz. This invention significantly improves the overall performance of the packaging material by optimizing the formulation and curing method of the epoxy resin composition. The encapsulated IPM can pass the HTRB test under conditions of 200°C, 1200V, and 1000h.

Description

Technical Field

[0001] This invention relates to the field of electronic device packaging materials technology, and in particular to a high Tg, low dielectric epoxy resin composition, its preparation method, and its application. Background Technology

[0002] Silicon carbide (SiC) has been widely used in the manufacture of intelligent power modules (IPMs) as a semiconductor material. Compared with traditional silicon (Si)-based materials, SiC-based IPMs have several significant advantages: (1) SiC materials can operate at higher temperatures, and the junction temperature (Tj) of SiC-based IPMs can typically reach 175°C or even higher. This allows SiC-based IPMs to maintain high efficiency and stable performance even at high temperatures; (2) SiC-based IPMs can withstand higher voltages, making them suitable for applications requiring high voltage, such as the traction drive system of electric vehicles; in some high-voltage applications, IPMs may need to have a withstand voltage of up to 1200V, in which case SiC-based IPMs become the ideal material.

[0003] Because SiC-based IPMs need to operate in high-temperature, high-pressure environments, the EMC (epoxy molding compound) encapsulation material must possess multiple properties, such as good high-temperature resistance, to ensure the reliability and stability of the product under high-temperature conditions. Simultaneously, the EMC should have excellent electrical insulation properties to prevent electrical breakdown and short circuits, ensuring the safe operation of the module. Furthermore, the lead frames of SiC-based high-power semiconductor devices are typically made of materials with good thermal and electrical conductivity (such as copper alloys) to ensure effective heat conduction and low-resistance electrical connections. Therefore, the EMC's coefficient of thermal expansion needs to match the frame, or it needs to have a low modulus, to reduce internal stress caused by temperature changes and prevent delamination or cracking between the EMC and other components after encapsulation. At the same time, to avoid delamination, the EMC needs sufficient adhesion to various materials at 200°C; for example, nickel plating of the frame leads requires good adhesion of the EMC to nickel. Due to the large size of high-power semiconductor devices, voids are easily generated during encapsulation, increasing the risk of breakdown; therefore, the EMC needs to have suitable flowability. In order to effectively conduct and dissipate the heat generated by the chip, EMC needs to have low thermal resistance, thereby improving the thermal management efficiency of the module and ensuring that it can maintain a suitable operating temperature even at high power output.

[0004] Against this backdrop, existing EMC still faces many challenges. For instance, the high crosslinking density corresponding to high Tg (glass transition temperature) can limit ion migration pathways, but high Tg systems are usually highly polar, resulting in a limited reduction in dielectric constant (Dk) compared to low Tg systems. Furthermore, high Tg systems have higher resin modulus and viscosity, making it difficult to control the flowability of EMC. These are all challenges that are difficult to overcome in the design of existing EMC formulations.

[0005] Chinese invention patent application CN114250050A discloses an epoxy resin composition, its preparation, and its application in IGBT semiconductor packaging. By using a synergistic epoxy resin composition and nano-silica-modified boron phenolic resin in the IGBT packaging material, it solves the problem of poor durability of existing packaging materials at high temperatures, improves the material's thermal stability, and extends its service life. Chinese invention patent CN113201204B discloses a high-Tg, low-warpage MUF epoxy resin composition and its preparation method. By using multifunctional epoxy resin and phenolic resin in the epoxy resin composition, combined with low-viscosity epoxy resin and fillers, it solves the problems of high shrinkage and easy warpage in existing epoxy resin compositions, achieving high Tg, low warpage, and flame retardant properties, suitable for industrial applications of molded bottom packaging. However, these existing technologies have not solved the aforementioned technical problems, and the products still struggle to meet HTRB testing requirements.

[0006] Against this backdrop, there is an urgent need to provide a packaging material that can balance suitable flowability, high Tg, low dielectric, good insulation, and pass HTRB testing. Summary of the Invention

[0007] For automotive IPM devices, HTRB (High Temperature Reverse Bias) testing is a key indicator of their quality. Because power devices in automotive applications often operate under high temperature and high voltage environments, higher reliability requirements are placed on them. Passing HTRB testing ensures the safety and stability of IPMs in automotive applications, thus preventing potential failures such as circuit board fires. HTRB testing is an important method for evaluating the reliability of power semiconductor devices under high temperature and high voltage stress. The choice of packaging material has a significant impact on HTRB test results, directly affecting the thermal performance and mechanical stability of the device. Its dielectric properties under high temperature and low frequency conditions are crucial for the design and application of SiC-based IPMs. This invention, through research, optimizes a high-temperature resistant epoxy resin curing system, combines it with a specific fluorinated epoxy resin, and uses a specific three-stage curing process to obtain an epoxy resin composition suitable for SiC-based materials, with a maximum Tj of 200℃, capable of meeting the 1200V rated voltage requirement for IPM packaging. IPMs packaged with this composition can pass HTRB testing under conditions of 200℃, 1200V, and 1000h.

[0008] The first aspect of the present invention provides an epoxy resin composition, which, by weight, comprises 35-70 parts of a multifunctional epoxy resin, 10-20 parts of a fluorinated epoxy resin, 10-15 parts of a low-stress agent, 0.2-5 parts of an adhesion promoter, 2-4 parts of a release agent, 500-1000 parts of a filler, 0.2-1 parts of a catalyst, and 35-50 parts of a curing agent.

[0009] Optionally, the epoxy resin composition has a Tg of 250°C or higher and a Dk of 10 or lower under test conditions of 200°C and 0.1Hz.

[0010] Optionally, the multifunctional epoxy resin includes a first multifunctional epoxy resin and a second multifunctional epoxy resin; the mass ratio of the first multifunctional epoxy resin and the second multifunctional epoxy resin is (5-10):1; further optionally, it is (6-7):1.

[0011] Optionally, the functionality of the first multifunctional epoxy resin is 3.

[0012] Further optionally, the structural formula of the first multifunctional epoxy resin is as follows: .

[0013] The epoxy equivalent of the first multifunctional epoxy resin is 120-200 g / mol; further preferably 165-175 g / mol; and most preferably 169 g / mol.

[0014] Optionally, the functionality of the second multifunctional epoxy resin is 4.

[0015] Further optionally, the structural formula of the second multifunctional epoxy resin is as follows: .

[0016] Optionally, the epoxy equivalent of the second multifunctional epoxy resin is 120-200 g / mol; further preferably 160-170 g / mol; and most preferably 162 g / mol.

[0017] Optionally, the curing agent is a phenolic resin, which includes a first phenolic resin and a second phenolic resin; the mass ratio of the first phenolic resin and the second phenolic resin is (2-4):1.

[0018] Optionally, the first phenolic resin is a multifunctional phenolic resin, and the structural formula of the multifunctional epoxy resin is as follows: .

[0019] Optionally, the hydroxyl equivalent of the multifunctional phenolic resin is 90-150 g / mol; further preferably 100-120 g / mol; and most preferably 103 g / mol.

[0020] Optionally, the second phenolic resin is a polycyclic aromatic hydrocarbon (PAH) type phenolic resin. Examples of PAH type phenolic resins include: The hydroxyl equivalent of the polycyclic aromatic hydrocarbon phenolic resin is 200-250 g / mol; it can be further selected as 215 g / mol.

[0021] The polycyclic aromatic phenolic resin has low polarity, which can adjust the viscosity of the resin system without affecting the Dk of the system after addition; however, excessive addition will reduce the Tg of the epoxy resin composition. In order to take into account the overall performance of the epoxy resin composition, the amount of polycyclic aromatic phenolic resin added is 5-15 parts.

[0022] Optionally, the ratio of the total number of epoxy groups in the multifunctional epoxy resin to the total number of hydroxyl groups in the curing agent is 0.7-1.1; more preferably, it is 0.8-0.9.

[0023] Optionally, the fluorinated epoxy resin has the following structural formula: , n=1.

[0024] Optionally, the fluorine content in the fluorinated epoxy resin is 40-60 wt%; more preferably 49.5 wt%.

[0025] Optionally, the amount of the fluorinated epoxy resin added to the epoxy resin composition is 10-18 parts; for example, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, or 18 parts; most preferably, it is 15 parts.

[0026] Optionally, the fluorine content in the epoxy resin composition is 0.1-2 wt%, more preferably 0.3-1.1 wt%, and most preferably 0.9 wt% (corresponding to 15 parts of fluorinated epoxy resin added to the epoxy resin composition).

[0027] Introducing low-polarity chemical groups into epoxy resin molecules can lower their dielectric constant, but this has negative effects on the material's heat capacity (Tg) and adhesion. Furthermore, due to polarity differences, excessively high fluorine content leads to poor compatibility with general epoxy resins, especially for multifunctional epoxy resins and curing agents, where the polarity difference is even greater than that of fluorinated resins, making compatibility issues even more pronounced. This invention preferably provides a fluorinated epoxy resin with a specific structure that balances high Tg and low dielectric constant, enabling the IPM (Integrated Product Mass) of the encapsulation material to pass the HTRB test.

[0028] Optionally, the low-stress agent may include at least one of the following: silicone-based low-stress agent, MBS (methyl methacrylate-butadiene-styrene terpolymer) low-stress agent, and polyurethane-based low-stress agent.

[0029] To improve the high-temperature resistance of the epoxy resin composition, the low-stress agent includes an organosilicon-based low-stress agent; further optionally, it is KPM594.

[0030] Optionally, the adhesive strength enhancer may include zinc coordination compounds, organosilicon polysulfides, imidazolylsilanes, mercaptosilanes, etc.

[0031] As an example of a zinc coordination compound, 1,3,5-triazine-2,4,6(1H,3H,5H)-trione zinc salt can be selected, with the following structural formula: The CAS number is 24468-28-8.

[0032] In some embodiments, the amount of the zinc coordination compound added is 0.2-0.6 parts, and more preferably 0.3-0.4 parts.

[0033] As an example of organosilicon polysulfides, one can choose , where x = 2 - 4, for example 2, 3, 4.

[0034] In some embodiments, the amount of the organosilicon polysulfide compound added is 1-1.5 parts, and more preferably 1.2-1.3 parts.

[0035] As an example of an imidazolylsilane, an imidazolyltrimethoxysilane may be selected, and further options may be selected... .

[0036] Optionally, R is an alkylene group, which is derived from Shikoku Chemical and traded under the name 2MUSIZ.

[0037] In some embodiments, the amount of imidazolylsilane added is 0.8-1.2 parts, and more preferably 1.0 parts.

[0038] As an example of a mercaptosilane, 3-mercaptopropyltrimethoxysilane can be selected, with the structural formula: .

[0039] In some embodiments, the amount of mercaptosilane added is 2-4 parts, and more preferably 3-3.5 parts.

[0040] Optionally, the adhesive strength enhancer comprises a zinc coordination compound and a mercaptosilane; the mass ratio of the zinc coordination compound to the mercaptosilane is (6-10):1.

[0041] In this invention, the adhesive strength enhancer is a zinc coordination compound and a mercaptosilane used in a mass ratio of (6-10):1. This combination of the two enhancers can achieve synergistic effects and significantly improve the adhesive performance of the epoxy resin composition under high temperature conditions. Among them, zinc coordination compounds (such as 1,3,5-triazine-2,4,6(1H,3H,5H)-zinc triketone salt) are mainly responsible for "surface modification" and "physical reinforcement". By constructing a stable, dense passivation / complex transition layer with a certain roughness on the metal surface in situ, the surface properties of the metal are optimized, which greatly enhances the mechanical interlocking and physical adsorption between the epoxy resin / silicone system and the metal substrate. At the same time, the compound itself also plays a physical reinforcing role in the resin matrix, ultimately achieving the improvement of adhesion. Mercaptosilanes (such as 3-mercaptopropyltrimethoxysilane) play the role of "molecular bridge" to improve the adhesion between epoxy resin (especially the silica-containing system) and the substrate. Utilizing its own bifunctional structure, it forms a strong chemical bond with the substrate on one side and undergoes a chemical reaction or physical entanglement with the silica-containing epoxy resin matrix on the other side, thereby tightly connecting two materials with completely different properties. Zinc coordination compounds and mercaptosilanes are compounded in a specific ratio to ensure a balance of the overall properties of the packaging material, significantly improving the structural stability and long-term reliability of IPM devices.

[0042] Release agents may include polyethylene wax, oxidized polyethylene wax, and silicone oil.

[0043] Optionally, in order to ensure that the molded PKG (semiconductor device package formed by molding process) can be successfully demolded, the release agent includes oxidized polyethylene wax and polyethylene wax; further optionally, the mass ratio of oxidized polyethylene wax and polyethylene wax is (0.8-1.2):1; most preferably 1:1.

[0044] In some embodiments, the oxidized polyethylene wax may further be a branched oxidized polyethylene wax.

[0045] The fillers may include silica powder, aluminum oxide, aluminum nitride, glass microspheres, etc.

[0046] To give the epoxy resin composition suitable flowability, CTE (coefficient of thermal expansion), and modulus, the filler may optionally include silica powder; more preferably, the silica powder may include spherical silica powder and molten angular silica powder; the mass ratio of the spherical silica powder to the molten angular silica powder is (8-12):1; for example, 8:1, 9:1, 10:1, 11:1, 12:1; more preferably, 10:1.

[0047] Optionally, the maximum particle size (cut size) of the spherical silicon powder is 60-100 μm, and the median particle size (D50) is 20-25 μm; more preferably, the maximum particle size of the spherical silicon powder is 75 μm, and the median particle size is 23 μm.

[0048] Optionally, the maximum particle size of the molten angular silicon powder is 60-100 μm, and the median particle size is 5-10 μm; more preferably, the maximum particle size of the molten angular silicon powder is 75 μm, and the median particle size is 7 μm.

[0049] Optionally, the amount of silicon powder added accounts for 78-85 wt% of the total mass of epoxy resin; for example, 78 wt%, 79 wt%, 80 wt%, 81 wt%, 82 wt%, 83 wt%, 84 wt%, 85 wt%; and more preferably 82%.

[0050] To improve the thermal conductivity and overall compatibility of the system, the filler also includes aluminum oxide; optionally, the maximum particle size of the aluminum oxide is 60-100 μm and the median particle size is 10-30 μm; further optionally, the maximum particle size of the aluminum oxide is 75 μm and the median particle size is 19.5 μm.

[0051] In some embodiments, the aluminum oxide is spherical aluminum oxide.

[0052] Optionally, the mass ratio of the silicon powder to aluminum oxide is (15-30):1.

[0053] In some embodiments, the catalyst may be exemplified as 2MZ-A, which is an imidazole-type catalyst sourced from Shikoku Chemical Co., Ltd. of Japan.

[0054] In some embodiments, the epoxy resin composition further includes a pigment, wherein the amount of pigment added is 1-4 parts.

[0055] As an example of a pigment, carbon black can be chosen.

[0056] The dielectric constant (Dk) of the packaging material is an important parameter in HTRB (High Temperature Reverse Bias) testing. Lowering the dielectric constant of the dielectric material used in integrated circuits can reduce leakage current, capacitance between wires, and heat generation, among other things. The dielectric constant is related to Tg (temperature gating) and ionic impurities; high temperatures activate free ions (such as Na+) in EMC. + Cl - Under low-frequency electric fields, these molecules slowly migrate to the interface, exacerbating the polarization effect and increasing Dk. High Tg inhibits molecular chain segment movement, reduces dipole polarization, and restricts ion migration paths. This invention, through specific epoxy resin composition formulation design, can maximize system compatibility and reduce Dk, thereby optimizing the insulation properties of the encapsulation material.

[0057] A second aspect of the present invention provides a method for preparing an epoxy resin composition, wherein the preparation steps of the epoxy resin composition include: (1) First, the multifunctional epoxy resin, fluorinated epoxy resin, curing agent and release agent are crushed and sieved, then mixed with the catalyst and dispersed in a crusher to obtain a pre-dispersed masterbatch; (2) Mix the pre-dispersed masterbatch, low stress agent, adhesive agent and filler, and then extrude, press, crush and shape in sequence to obtain the finished product.

[0058] Optionally, the particle size of the sieve is 50-200 mesh; for example, 50 mesh, 80 mesh, 100 mesh, 150 mesh, 200 mesh; and further optionally, 100 mesh.

[0059] Optionally, the extrusion process heats the material, kneads the material into a melt, and controls the temperature of the melt to be below 130°C.

[0060] In some embodiments, the preparation steps of the epoxy resin composition include: (1) First, the multifunctional epoxy resin, fluorinated epoxy resin, curing agent and release agent are crushed and passed through a 100-mesh sieve, then mixed with the catalyst and dispersed in a pulverizer to obtain a pre-dispersed masterbatch. (2) Mix the pre-dispersed masterbatch, low stress agent, adhesive agent and filler, heat and knead them into a melt through an extruder (the melt temperature is controlled below 130℃), then use a calender to extrude the melt into a sheet, use a pulverizer to crush it, and use a patting machine to shape it to obtain the finished product.

[0061] A third aspect of the present invention provides a method of using an epoxy resin composition, wherein the epoxy resin composition is subjected to staged curing during use.

[0062] To promote the optimal crosslinking density of the cured system, the segmented curing can optionally be a three-stage curing process, consisting of a first-stage curing, a second-stage curing, and a third-stage curing.

[0063] Optionally, the curing temperature of the first stage is 170-180℃, and the curing time is 80-120s; further optionally, the curing temperature is 175℃ and the curing time is 100s.

[0064] Optionally, the curing temperature for the second stage is 170-180℃, and the curing time is more than 1 hour; further, it can be cured at 175℃ for 2 hours.

[0065] Optionally, the curing temperature for the three stages is 180-220℃, and the curing time is more than 3 hours; further, it can be cured at 200℃ for 4 hours.

[0066] This invention employs a unique curing process with a specific three-stage curing method, ensuring the complete consumption of polar groups within the epoxy resin composition system. Since HTRB testing of high-power semiconductor devices is performed at 1200V, the insulation properties of the encapsulation material are particularly important, requiring excellent CTI, breakdown field strength, and high-temperature volume resistivity. The curing method of this invention, combined with a specific formulation, enhances the overall performance of the encapsulation material, meeting the requirements for IPM applications.

[0067] The epoxy resin composition of the present invention can meet the index requirements in Table 1 below.

[0068] Table 1

[0069] A fourth aspect of the present invention provides an application of an epoxy resin composition used in the manufacture of modular power electronic devices (such as IPMs).

[0070] Beneficial effects: This invention provides a high-Tg, low-dielectric epoxy resin composition, its preparation method, and its application, which have the following advantages: (1) This invention constructs a multifunctional epoxy resin curing system to prepare a high Tg polymer composite material. By using a specific blending ratio of first and second multifunctional epoxy resins, combined with a multifunctional phenolic resin curing agent, and controlling the ratio of the total number of epoxy groups in the epoxy resin to the total number of hydroxyl groups in the phenolic resin to be 0.8-0.9, and using a staged curing process, the Tg of the obtained material can reach above 250°C, which can achieve long-term performance stability of IPM module transfer molding encapsulation in high-temperature environments.

[0071] (2) The present invention constructs a special fluorinated epoxy resin application system to prepare a material with excellent Dk performance under high temperature and low frequency conditions. Under the high temperature and low frequency test conditions of 200℃ and 0.1Hz, the material Dk < 10, which can ensure the insulation and signal transmission stability of the IPM module in high frequency applications.

[0072] (3) By optimizing the formulation and process system, this invention effectively improves the comprehensive performance of the epoxy resin composition. The prepared polymer composite material has excellent properties such as heat resistance, insulation, thermal conductivity, flowability, and adhesion. The specific selection of resin and filler reduces the thermal stress of the system. The addition of suitable adhesive additives further enhances the adhesion to copper and nickel. Moreover, the low-stress, high-adhesion encapsulation material makes the device less prone to delamination under high-temperature operating conditions, significantly improving the practicality of the encapsulation material.

[0073] (4) By optimizing the epoxy resin and phenolic resin and the filler content, the resulting composition has excellent flowability and can balance the various properties of the encapsulation material. The resulting material is suitable for transfer molding encapsulation and can achieve reliable and consistent encapsulation. More importantly, it can pass the HTRB test under harsh conditions (1200V, 200℃, 1000h) to achieve long-term stable operation of the device under harsh environments such as high temperature and high pressure.

[0074] (5) In this invention, the adhesive strength enhancer is a zinc coordination compound and a mercaptosilane in a mass ratio of (6-10):1. This can achieve synergistic effect of the two enhancers, greatly improve the adhesive performance of the epoxy resin composition in high temperature environment, avoid the problem of insufficient adhesive effect or poor system compatibility caused by the addition of a single enhancer, ensure the balance of the comprehensive characteristics of the encapsulation material, and significantly improve the structural stability and long-term reliability of IPM devices.

[0075] (6) The epoxy resin composition of the present invention can meet the manufacturing requirements of IPM, especially it can encapsulate IPM modules with a large volume such as 100mm×60mm×10mm, with a wide range of applications, strong practicality and operability. Detailed Implementation

[0076] The fluorinated epoxy resin used in the following embodiments was self-made by Tianjin Dega Chemical New Materials Co., Ltd., and the preparation steps include: (1) Friedel-Crafts reaction: 48.05 g of fluorobenzene and 10 g of anhydrous AlCl3 (catalyst) were added to a 250 mL three-necked flask equipped with a stirrer, condenser and gas inlet tube; 166.03 g of hexafluoroacetone gas was introduced into an ice bath at -5~0℃ and stirred vigorously; after the viscosity of the reaction mixture increased, the temperature was raised above 0℃ and below 25℃ to continue the reaction, during which 5 g of anhydrous AlCl3 was added to maintain the reaction rate until the viscosity of the reaction mixture no longer increased, and the reaction was completed; the mixture was diluted with dichloromethane and poured into ice water; the organic phase was separated and the aqueous phase was extracted with dichloromethane (200 mL); the organic phases were combined and the dichloromethane was removed by rotary evaporation; 156 g of 2,4-bis(1,1,1,3,3,3-hexafluoro-2-hydroxyisopropyl)fluorobenzene (denoted as FB-OH) was obtained by vacuum distillation, with a yield of 72.9%; (2) Glycidyl etherification reaction: 40g FB-OH, 172.1g epichlorohydrin and 8.2g NaOH were added to a reaction flask equipped with a reflux condenser and stirred at 110℃ for 12 hours (epoxychlorohydrin was added in excess to reduce oligomer formation); after the reaction, the generated NaCl was removed by filtration and the excess epichlorohydrin was removed by vacuum distillation of the filtrate to obtain 47.7g of pale yellow viscous liquid (i.e. fluorinated epoxy resin).

[0077] Unless otherwise specified, all raw materials, equipment and other consumables used in this invention are commercially available.

[0078] Examples 1-3 and Comparative Examples 1-7 Examples 1-3 and Comparative Examples 1-7 respectively provide an epoxy resin composition and its preparation and application methods. The formulation information is shown in Table 2-3; the units of the values ​​in Table 2-3 are parts by weight.

[0079] Table 2

[0080] Table 3

[0081] Information on the raw materials used in Examples 1-3 and Comparative Examples 1-7 is shown in Table 4.

[0082] Table 4

[0083] The preparation steps of the epoxy resin compositions in Examples 1-3 and Comparative Examples 1-7 include: (1) First, the multifunctional epoxy resin, fluorinated epoxy resin, curing agent and release agent are crushed and passed through a 100-mesh sieve, then mixed with the catalyst and dispersed in a pulverizer to obtain a pre-dispersed masterbatch. (2) Mix the pre-dispersed masterbatch, low stress agent, adhesive agent and filler, heat and knead them into a melt through an extruder (the melt temperature is controlled below 130℃), then use a calender to extrude the melt into a sheet, use a pulverizer to crush it, and use a patting machine to shape it to obtain the finished product.

[0084] The epoxy resin compositions of Examples 1-3 and Comparative Examples 1-4, 6, and 7 were cured in three stages during use: first stage curing, second stage curing, and third stage curing. The first stage curing was performed at 175°C for 100 seconds, the second stage curing was performed at 175°C for 2 hours, and the third stage curing was performed at 200°C for 4 hours.

[0085] The epoxy resin composition of Comparative Example 5 was not cured in stages during use. The curing conditions were: 175℃ for 5 hours.

[0086] Performance testing The epoxy resin compositions of Examples 1-3 and Comparative Examples 1-7 and their cured products were subjected to performance tests. The test results are shown in Table 5. Among them, the gel time, spiral flow length and viscosity were tested before the epoxy resin compositions were cured, and the other test items were tested on the cured products.

[0087] The criteria for judging moldability are: no sticking, poor filling, surface porosity, etc., no problems with operation during molding, and no problems with the appearance of the molded PKG are recorded as qualified; if the above problems occur, it is recorded as NG.

[0088] The HTRB test method is as follows: take the IPM device as a sample and perform the HTRB test according to AEC-Q101; if no abnormality is found, it is recorded as Pass; if abnormalities such as mucus or pores are found, it is recorded as NG.

[0089] All other parameters were measured in accordance with GB / T 40564-2021.

[0090] Table 5

[0091] As shown in Table 5, Examples 1-3 of the present invention use a preferred epoxy resin curing system and curing method, and the final product has the technical effects of high Tg, low dielectric, good adhesion, good film-forming properties, and can pass the HTRB test. However, in Comparative Examples 1-7, the formulation adjustment of the epoxy resin composition (such as release agent, adhesion promoter, fluorinated epoxy resin, low stress agent, etc.) or the adjustment of the curing method will result in the deterioration of the performance of the final product. In particular, the HTRB test will show results such as internal pores, leakage current, and framework delamination, which cannot meet the IPM manufacturing requirements.

Claims

1. A high Tg, low dielectric epoxy resin composition characterized in that, According to parts by weight, the epoxy resin composition comprises 35-70 parts of multifunctional epoxy resin, 15-20 parts of fluorinated epoxy resin, 10-15 parts of low-stress agent, 0.2-5 parts of adhesion promoter, 2-4 parts of release agent, 500-1000 parts of filler, 0.2-1 parts of catalyst, and 35-50 parts of curing agent. The multifunctional epoxy resin includes a first multifunctional epoxy resin and a second multifunctional epoxy resin. The first multifunctional epoxy resin has a functionality of 3 and an epoxy equivalent of 120-200 g / mol; The second multifunctional epoxy resin has a functionality of 4 and an epoxy equivalent of 120-200 g / mol; The curing agent is a phenolic resin, which includes a first phenolic resin and a second phenolic resin. The first phenolic resin is a multifunctional phenolic resin with a hydroxyl equivalent of 90-150 g / mol; The second phenolic resin is a polycyclic aromatic hydrocarbon type phenolic resin with a hydroxyl equivalent of 200-250 g / mol; The adhesive strength enhancer comprises a zinc coordination compound and a mercaptosilane, wherein the mass ratio of the zinc coordination compound to the mercaptosilane is 1:(6-10). The release agent comprises oxidized polyethylene wax and polyethylene wax, wherein the mass ratio of oxidized polyethylene wax to polyethylene wax is (0.8-1.2):1; The amount of the polycyclic aromatic hydrocarbon phenolic resin added is 5-15 parts; The epoxy resin composition has a Tg of 250°C or higher, and the epoxy resin composition has a Dk of 10 or lower under test conditions of 200°C and 0.1Hz. The fluorine content in the fluorinated epoxy resin is 40-60 wt%.

2. The high Tg, low dielectric epoxy resin composition of claim 1, wherein, The low-stress agent includes an organosilicon-based low-stress agent.

3. The high Tg, low dielectric epoxy resin composition of claim 1, wherein, The filler includes silicon powder; the silicon powder includes spherical silicon powder and molten angular silicon powder; the mass ratio of the spherical silicon powder to the molten angular silicon powder is (8-12):1; The maximum particle size of the spherical silicon powder is 60-100 μm, and the median particle size is 20-25 μm; The maximum particle size of the molten angular silicon powder is 60-100 μm, and the median particle size is 5-10 μm.

4. The high Tg, low dielectric epoxy resin composition of claim 3, wherein, The filler also includes aluminum oxide; the maximum particle size of the aluminum oxide is 60-100 μm, and the median particle size is 10-30 μm.

5. The high Tg, low dielectric epoxy resin composition of claim 4, wherein, The mass ratio of silicon powder to aluminum oxide is (15-30):

1.

6. A method of preparing a high Tg, low dielectric epoxy resin composition according to any one of claims 1 to 5, characterized in that, The preparation steps of the epoxy resin composition include: (1) First, the multifunctional epoxy resin, fluorinated epoxy resin, curing agent and release agent are crushed and sieved, then mixed with the catalyst and dispersed in a crusher to obtain a pre-dispersed masterbatch; (2) Mix the pre-dispersed masterbatch, low stress agent, adhesive agent and filler, and then extrude, press, crush and shape in sequence to obtain the finished product.

7. A method of using the high Tg, low dielectric epoxy resin composition according to any one of claims 1-5, characterized in that, The epoxy resin composition is cured in stages during use.

8. The method of using a high Tg, low dielectric epoxy resin composition according to claim 7, wherein, The segmented curing process consists of three stages: a first-stage curing, a second-stage curing, and a third-stage curing. The curing temperature of the first section is 170-180℃, and the curing time is 80-120 seconds. The curing temperature for the second stage is 170-180℃, and the curing time is more than 1 hour. The curing temperature for the three stages is 180-220℃, and the curing time is more than 3 hours.

9. Use of a high Tg, low dielectric epoxy resin composition according to any one of claims 1 to 5, characterized in that, The epoxy resin composition is applied to the manufacture of modular power electronics.

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