Ultralow-stress epoxy resin forming material and preparation method thereof

Abstract

The invention relates to the field of epoxy resin composite materials, in particular to an ultralow-stress epoxy resin forming material and a preparation method thereof. The ultralow-stress epoxy resin molding material is prepared from a raw material composition of epoxy resin, phenolic resin, inorganic filler, an accelerant, a tackifier, a coupling agent, a release agent, an ion capturing agent, a coloring agent and a stress modifier in specific types and proportions. The epoxy resin composition contains epoxy resin with the structures shown in the formula (1) and the formula (2) and a curing agent, and the curing accelerator and the tackifier with appropriate types and dosage are added, so that the prepared epoxy resin forming material has ultralow stress, keeps high binding force with different metal coatings, has the humidity sensitivity grade reaching the MSL-1 grade, and can be used for preparing the high-strength epoxy resin forming material with the humidity sensitivity grade reaching the MSL-1 grade. And the high reliability requirement of the device can be met.

Description

Technical Field

[0001] The invention relates to the field of epoxy resin composite materials, and in particular to an ultra-low stress epoxy resin molding material and a preparation method thereof. Background Art

[0002] Epoxy resin-based composite materials have the characteristics of low cost, stable reliability and suitability for large-scale industrial production. They have occupied more than 95% of the market share of electronic packaging materials and are the preferred material in packaging fields such as integrated circuits, industrial switches, household appliances, and new energy vehicles.

[0003] The packaging materials that make up semiconductor devices include silicon wafers, frames, solder paste, etc. The thermal expansion coefficients of these materials are very different from those of epoxy resin molding materials. The packaging process will undergo a high-temperature welding process, which will generate a lot of thermal stress, which is very likely to cause chip damage and cracking of the plastic package, resulting in electrical performance failure. In recent years, with the rapid development of semiconductor packaging technology towards miniaturization, multifunctionality, and high reliability, especially the rapid development of the new energy vehicle field, the reliability requirements for vehicle-mounted electronic packaging materials are getting higher and higher. The reliability of traditional epoxy resin molding materials is gradually unable to meet the requirements, so it is necessary to develop new ultra-low stress epoxy resin molding materials. The traditional technical solution is usually to add some silicone rubber or silicone oil that is incompatible with epoxy resin as a low stress modifier in the composition to reduce the stress level, but this method is very easy to seep out due to the incompatibility of the modifier with the resin itself, and the level of stress reduction is limited. At the same time, there will be interface stratification problems caused by reduced adhesion. Summary of the invention

[0004] In view of the defects of the current technical solutions, the present invention provides an ultra-low stress epoxy resin molding material and a preparation method. The epoxy resin material composition comprises epoxy resin and curing agent in a specific ratio, and through the use of appropriate types and amounts of curing accelerators and tackifiers, the prepared epoxy composition has the properties of ultra-low stress, higher glass transition temperature (Tg), high bonding strength, etc. At the same time, the moisture sensitivity level reaches MSL-1 level, which can meet the high reliability requirements of the device.

[0005] The technical solution of the present invention to solve the technical problem is as follows:

[0006] In a first aspect of the present invention, an ultra-low stress epoxy resin molding material is provided. The raw material composition for preparing the molding material comprises 5-15wt% of epoxy resin, 1-10wt% of phenolic resin curing agent, 70-90wt% of inorganic filler, 0.1-1wt% of curing accelerator, 0.05-1wt% of tackifier, 0.1-1wt% of coupling agent, 0.1-1wt% of release agent, 0.1-1wt% of ion capture agent, 0.1-1wt% of colorant, and 0.1-1wt% of stress modifier, based on the total weight of the raw material composition as 100wt%;

[0007] The epoxy resin is a polymer having a structure as shown in formula (1):

[0008]

[0009] In formula (1), n=1-20, and the epoxy equivalent is 261-282 g / eq.

[0010] The phenolic resin curing agent is a polymer having a structure as shown in formula (2):

[0011]

[0012] In formula (2), n=1-20, and the hydroxyl equivalent is 201-220 g / eq.

[0013] Preferably, the raw material composition of the molding material comprises 6-12wt% of epoxy resin, 1-5wt% of phenolic resin curing agent, 80-90wt% of inorganic filler, 0.1-0.5wt% of curing accelerator, 0.05-0.3wt% of tackifier, 0.1-0.5wt% of coupling agent, 0.1-0.5wt% of release agent, 0.2-0.8wt% of ion capture agent, 0.2-0.6wt% of colorant and 0.1-0.5wt% of stress modifier.

[0014] Preferably, the inorganic filler is crystalline silica and / or fused silica. More preferably, the inorganic filler is fused silica. Further preferably, the median particle size of the inorganic filler is 15-30 μm.

[0015] Preferably, the curing accelerator is one or more of 2-methylimidazole, 2-ethyl-4-methylimidazole, triphenylphosphine, triphenylphosphine / p-benzoquinone complex, triphenylphosphine / phenol complex, and tetraphenylphosphine salt. More preferably, the curing accelerator is triphenylphosphine / p-benzoquinone complex and / or triphenylphosphine / phenol complex.

[0016] Preferably, the tackifier is an acid anhydride derivative and / or a triazole composition. More preferably, the tackifier is a triazole composition.

[0017] Preferably, the coupling agent is one or more of N-phenyl-3-aminopropyl trimethoxysilane, bis-(3-triethoxysilylpropyl)-tetrasulfide, γ-glycidyloxypropyl trimethoxysilane, 3-mercaptopropyl trimethoxysilane, and isocyanate silane. More preferably, the coupling agent is one or more of N-phenyl-3-aminopropyl trimethoxysilane, γ-glycidyloxypropyl trimethoxysilane, and 3-mercaptopropyl trimethoxysilane.

[0018] Preferably, the release agent is mineral wax and / or erucamide. More preferably, the release agent is erucamide.

[0019] Preferably, the stress modifier is selected from epoxidized organosilicon glycidyl resin, triblock polymer containing organosilicon component, silicone resin, liquid carboxyl-terminated nitrile rubber. Further preferably, the stress modifier is liquid carboxyl-terminated nitrile rubber.

[0020] Preferably, the ion capture agent is a cation or anion capture agent, and the cation capture agent is a polyvalent metal acid salt and / or a hydrated oxide. The anion capture agent is selected from magnesium aluminum hydroxide type and / or hydrotalcite.

[0021] Preferably, the colorant is carbon black.

[0022] In a second aspect of the present invention, a method for preparing the epoxy resin molding material according to the first aspect is provided, the method comprising the following steps:

[0023] (1) Based on the total weight of the phenolic resin being 100 wt %, 10-40 wt % of a phenolic resin curing agent is heated and melted, and then a stress modifier is added, stirred, cooled and crushed to obtain an intermediate;

[0024] (2) mixing the intermediate obtained in step (1), epoxy resin, inorganic filler, coupling agent, curing accelerator, tackifier, ion trap, release agent, colorant and remaining phenolic resin using a mixer;

[0025] (3) Extruding, cooling, crushing and molding the high-mix material obtained in step (2) to obtain an epoxy resin molding material.

[0026] Preferably, in step (1), the heating temperature is 110-160°C.

[0027] Preferably, in step (3), the extrusion equipment is a twin-screw extruder, and the extrusion temperature is 90-115°C.

[0028] Preferably, in step (3), the molding equipment is a pressure cookie maker.

[0029] In a third aspect of the present invention, there is provided application of the epoxy resin molding material as described in the first aspect as a power device packaging material.

[0030] Compared with the prior art, the epoxy resin molding material and its preparation method of the present invention have the following beneficial effects:

[0031] (1) In the preparation method provided by the present invention, the stress modifier and part of the phenolic resin curing agent form an intermediate, thereby significantly improving the dispersion uniformity of the stress modifier in the resin matrix, significantly reducing the internal stress of the epoxy resin composition while maintaining high adhesion.

[0032] (2) In the present invention, by using a specific ratio of epoxy resin and phenolic resin curing agent, the prepared epoxy resin composition has a higher Tg and a lower stress level than traditional epoxy resin molding materials.

[0033] (3) In the present invention, by adding a curing accelerator and a tackifier of appropriate type and amount to the epoxy composition, the bonding strength between the epoxy material and the different metal plating layers of copper, silver and nickel is further improved, and the reliability is extremely high, meeting the requirements of the moisture sensitivity level MSL-1. DETAILED DESCRIPTION

[0034] The specific embodiments of the present invention are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0035] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0036] In the present invention, the epoxy resin composition contains epoxy resin and curing agent in a specific ratio, and through the use of appropriate types and amounts of curing accelerators and tackifiers, the prepared epoxy composition has properties such as ultra-low stress, high glass transition temperature (Tg), high bonding strength, etc., and the moisture sensitivity level reaches MSL-1 level, which can meet the high reliability requirements of the device.

[0037] The first aspect of the present invention provides an epoxy resin molding material, which, based on the total weight of the raw material composition as 100wt%, comprises 5-15wt% of epoxy resin, 1-10wt% of phenolic resin curing agent, 70-90wt% of inorganic filler, 0.1-1wt% of curing accelerator, 0.05-1wt% of tackifier, 0.1-1wt% of coupling agent, 0.1-1wt% of release agent, 0.1-1wt% of ion capture agent, 0.1-1wt% of colorant, and 0.1-1wt% of stress modifier.

[0038] The epoxy resin is a polymer having a structure as shown in formula (1):

[0039]

[0040] In formula (1), n=1-20, and the epoxy equivalent is 261-282 g / eq.

[0041] The phenolic resin curing agent is a polymer having a structure as shown in formula (2):

[0042]

[0043] In formula (2), n=1-20, and the hydroxyl equivalent is 201-220 g / eq.

[0044] Furthermore, the composition comprises 6-12wt% of epoxy resin, 1-5wt% of phenolic resin curing agent, 80-90wt% of inorganic filler, 0.1-0.5wt% of curing accelerator, 0.05-0.3wt% of tackifier, 0.1-0.5wt% of coupling agent, 0.1-0.5wt% of release agent, 0.2-0.8wt% of ion capture agent, 0.2-0.6wt% of colorant and 0.1-0.5wt% of stress modifier.

[0045] In the epoxy molding material of the present invention, in a specific embodiment, the inorganic filler is crystalline silica and / or molten silica. In a more preferred embodiment, the inorganic filler is molten silica. In a further preferred embodiment, the median particle size of the inorganic filler is 15-30 μm, which can be 15 μm, 20 μm, 25 μm, or 30 μm.

[0046] In the epoxy molding material of the present invention, in a specific embodiment, the curing accelerator is one or more of 2-methylimidazole, 2-ethyl-4-methylimidazole, triphenylphosphine, triphenylphosphine / p-benzoquinone complex, triphenylphosphine / phenol complex, and tetraphenylphosphine salt. In a more preferred embodiment, the curing accelerator is triphenylphosphine / p-benzoquinone complex and / or triphenylphosphine / phenol complex.

[0047] In the epoxy molding material of the present invention, in a specific embodiment, the tackifier is an acid anhydride derivative and / or a triazole composition. In a more preferred embodiment, the tackifier is a triazole composition.

[0048] In the epoxy molding material of the present invention, in a specific embodiment, the coupling agent is one or more of N-phenyl-3-aminopropyl trimethoxysilane, bis-(3-triethoxysilylpropyl)-tetrasulfide, γ-glycidyloxypropyl trimethoxysilane, 3-mercaptopropyl trimethoxysilane, and isocyanate silane. In a more preferred embodiment, the coupling agent is one or more of N-phenyl-3-aminopropyl trimethoxysilane, γ-glycidyloxypropyl trimethoxysilane, and 3-mercaptopropyl trimethoxysilane.

[0049] In the epoxy molding material of the present invention, in a specific embodiment, the release agent is mineral wax and / or erucic acid amide. In a more preferred embodiment, the release agent is erucic acid amide.

[0050] In the epoxy molding material of the present invention, in a specific embodiment, the stress modifier is selected from epoxidized organosilicon glycidyl resin, triblock polymer containing organosilicon component, silicone resin, liquid carboxyl-terminated nitrile rubber. In a more preferred embodiment, the stress modifier is liquid carboxyl-terminated nitrile rubber.

[0051] In the epoxy molding material of the present invention, in a specific embodiment, the ion capture agent is a cation or anion capture agent, and the cation capture agent is a polyvalent metal acid salt and / or a hydrated oxide. The anion capture agent is selected from magnesium aluminum hydroxide type and / or hydrotalcite.

[0052] In the epoxy molding material of the present invention, in a specific embodiment, the colorant is carbon black.

[0053] A second aspect of the present invention provides a method for preparing the epoxy resin molding material described above, the method comprising the following steps:

[0054] (1) Based on the total weight of the phenolic resin as 100wt%, 10-40wt% of a phenolic resin curing agent is heated and melted, and then a stress modifier is added, stirred, cooled, and crushed to obtain an intermediate;

[0055] (2) mixing the intermediate obtained in step (1), epoxy resin, inorganic filler, coupling agent, curing accelerator, tackifier, ion trap, release agent, colorant and remaining phenolic resin using a mixer;

[0056] (3) Extruding, cooling, crushing and molding the high-mix material obtained in step (2) to obtain an epoxy resin molding material.

[0057] In the method of the present invention, in step (1), the heating temperature is 110-160° C. In a specific embodiment, for example, it can be 110° C., 120° C., 130° C., 140° C., 150° C., 160° C. In a preferred embodiment, the heating temperature is 140° C.

[0058] In the method of the present invention, in step (3), the extrusion equipment is conventionally selected in the art. In a preferred embodiment, a twin-screw extruder is selected.

[0059] In the method of the present invention, in step (3), the extrusion temperature is 90-115° C. In a specific embodiment, it can be 90° C., 95° C., 100° C., 105° C., 110° C., 115° C. In a preferred embodiment, the extrusion temperature is 110° C.

[0060] In the method of the present invention, in step (3), the molding equipment is conventionally selected in the art. In a preferred embodiment, a pressure cookie maker is selected.

[0061] A third aspect of the present invention provides a use of the epoxy resin molding material described above as a power device packaging material.

[0062] The present invention will be described in detail below through examples, but the protection scope of the present invention is not limited thereto.

[0063] Unless otherwise specified, the reagents involved in the examples and comparative examples of the present invention are all commercially available products.

[0064] Epoxy resin with the structure shown in formula (1): purchased from Jinan Shengquan Group, brand name SQXN-323;

[0065] o-Cresol epoxy resin: purchased from Jinan Shengquan Group, brand SQCN700-1.3;

[0066] Linear phenolic resin: purchased from Shanghai Hengfeng Resin, brand name Resicare3010;

[0067] Xylock phenolic resin: purchased from Shanghai Hengfeng Resin, brand name Resicare3600L;

[0068] The polyaromatic phenolic resin of the structure shown in formula (2) was purchased from Shanghai Hengfeng Resin, with the brand name Resicare3900;

[0069] Inorganic filler: fused silica, purchased from Jiangsu Lianrui New Materials Co., Ltd., with a maximum particle size of 75 μm and a median particle size of 15-30 μm;

[0070] Curing accelerator: triphenylphosphine / p-benzoquinone complex, purchased from Nanjing Lanbian Biochemical Technology Co., Ltd., with the brands TB and TD;

[0071] Thickener: triazole composition, purchased from Jinan Daen Pharmaceutical Technology Co., Ltd., brand name AP-1;

[0072] Coupling agent: γ-glycidyloxypropyltrimethoxysilane, purchased from Shandong SICO New Materials Co., Ltd., brand name SICO-A118;

[0073] Release agent: erucamide, purchased from Jiangxi Dongyuan Technology Co., Ltd., brand erucamide;

[0074] Stress modifier: liquid carboxyl-terminated nitrile rubber, purchased from Jiadida New Materials Co., Ltd., brand CTBN 1300*13;

[0075] Ion scavenger: hydrotalcite, purchased from Kyowa Chemical Industry Co., Ltd., Japan, brand DHT-4A;

[0076] Colorant: Carbon black, purchased from Sichuan Zhenghao Technology New Materials Co., Ltd., brand number JY2021.

[0077] The raw material components of Examples 1-6 and Comparative Examples 1-6 were proportioned according to Table 1 and Table 2, respectively, and implemented according to the following method;

[0078] (1) Based on the total weight of the phenolic resin being 100 wt%, 30 wt% of the phenolic resin curing agent is heated and melted, and then a stress modifier is added, stirred, cooled, and crushed to obtain an intermediate. The heating temperature is 140°C.

[0079] (2) mixing the intermediate obtained in step (1), epoxy resin, inorganic filler, coupling agent, curing accelerator, tackifier, ion trap, release agent, colorant and remaining phenolic resin using a mixer;

[0080] (3) Extruding, cooling, crushing and molding the high-mixed material obtained in step (2) to obtain an epoxy resin molding material. The extrusion equipment is a twin-screw extruder, and the extrusion temperature is 110° C. The molding equipment is a pressure cookie making machine.

[0081] Table 1: Raw material ratios of Examples 1-6

[0082]

[0083]

[0084] Table 2: Raw material ratios of comparative examples 1-6

[0085]

[0086] Test Case

[0087] (1) Gelation time: hot plate method, heat the hot plate to 175 ± 1 ° C, take 0.3-0.5g of the above molding material sample powder and place it on the hot plate. The end point is when the powder gradually changes from fluid to gel, and the required time is read.

[0088] (2) Spiral flow length: Take 20±1g sample powder and measure it on an injection molding press with the aid of a spiral flow metal mold. The molding pressure is 70±2Kgf / cm 2 , the mold temperature is 175±2℃ for testing.

[0089] (3) Glass transition temperature and linear expansion coefficient: measured by thermomechanical analyzer (TMA). The sample size for TMA test is 5 mm*5 mm (diameter*thickness).

[0090] (4) Storage modulus: measured by dynamic mechanical analyzer (DMA). The sample size for DMA test is 60mm*13mm*1.5mm (length*width*thickness). The smaller the storage modulus, the smaller the internal stress of the epoxy resin molding material.

[0091] (5) Adhesion: Tensile method, take 15±1g sample powder and measure it on an injection molding press with the help of an adhesion mold. The metal substrate size is 60mm*25mm*0.8mm (length*width*thickness), and the sample size is 15mm*5mm (diameter*thickness). Use a universal testing machine to test the 180° peel strength.

[0092] (6) Determination of moisture sensitivity level: The qualified products were baked at 125°C for 24 hours, and then placed in a humidity chamber at 85°C and 85% RH for 168 hours to absorb moisture. After that, infrared reflow was performed three times (maximum temperature 260°C), and an ultrasonic scanner was used to determine the delamination of the products.

[0093] The results of testing the gel time, spiral flow length, glass transition temperature, linear expansion coefficient, storage modulus, adhesion and reliability of the epoxy resin composite materials prepared in Examples 1-6 and Comparative Examples 1-6 are shown in Table 3.

[0094] Table 3

[0095]

[0096]

[0097] From the comparison of the test results of Examples 1-6 and Comparative Examples 1-6, it can be seen that the epoxy resin molding material of the present invention has an extremely low linear expansion coefficient, a low stress level, and Tg is still maintained at a relatively high level. While having a low storage modulus, it also has good adhesion with different metal coatings, has extremely high reliability, and meets the moisture sensitivity level MSL-1 requirements.

[0098] The above are only embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An ultra-low stress epoxy resin molding material, characterized in that: The raw material composition for preparing the molding material comprises 5-15wt% of epoxy resin, 1-10wt% of phenolic resin curing agent, 70-90wt% of inorganic filler, 0.1-1wt% of curing accelerator, 0.05-1wt% of tackifier, 0.1-1wt% of coupling agent, 0.1-1wt% of release agent, 0.1-1wt% of ion capture agent, 0.1-1wt% of colorant, and 0.1-1wt% of stress modifier, based on the total weight of the raw material composition being 100wt%; The epoxy resin is a polymer having a structure as shown in formula (1): In formula (1), n=1-20, epoxy equivalent 261-282 g / eq; The phenolic resin curing agent is a polymer having a structure as shown in formula (2): In formula (2), n=1-20, and the hydroxyl equivalent is 201-220 g / eq.

2. The ultra-low stress epoxy resin molding material according to claim 1, characterized in that: The raw material composition of the molding material includes 6-12wt% of epoxy resin, 1-5wt% of phenolic resin curing agent, 80-90wt% of inorganic filler, 0.1-0.5wt% of curing accelerator, 0.05-0.3wt% of tackifier, 0.1-0.5wt% of coupling agent, 0.1-0.5wt% of release agent, 0.2-0.8wt% of ion capture agent, 0.2-0.6wt% of colorant and 0.1-0.5wt% of stress modifier.

3. The ultra-low stress epoxy resin molding material according to claim 1, characterized in that: The inorganic filler is crystalline silica and / or fused silica.

4. The ultra-low stress epoxy resin molding material according to claim 1, characterized in that: The curing accelerator is one or more of 2-methylimidazole, 2-ethyl-4-methylimidazole, triphenylphosphine, triphenylphosphine / p-benzoquinone complex, triphenylphosphine / phenol complex, and tetraphenylphosphine salt.

5. The ultra-low stress epoxy resin molding material according to claim 1, characterized in that: The tackifier is an acid anhydride derivative and / or a triazole composition.

6. The ultra-low stress epoxy resin molding material according to claim 1, characterized in that: The coupling agent is one or more of N-phenyl-3-aminopropyltrimethoxysilane, bis-(3-triethoxysilylpropyl)-tetrasulfide, γ-glycidyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane and isocyanate-based silane.

7. The ultra-low stress epoxy resin molding material according to claim 1, characterized in that: The release agent is mineral wax and / or erucamide.

8. The ultra-low stress epoxy resin molding material according to claim 1, characterized in that: The stress modifier is selected from epoxidized organosilicon glycidyl resin, triblock polymer containing organosilicon component, silicone resin or liquid carboxyl-terminated nitrile rubber.

9. The ultra-low stress epoxy resin molding material according to claim 1, characterized in that: The ion capture agent is a cation capture agent or anion capture agent, the cation capture agent is a polyvalent metal acid salt and / or a hydrated oxide, and the anion capture agent is selected from magnesium aluminum hydroxide type and / or hydrotalcite.

10. A method for preparing an epoxy resin molding material according to any one of claims 1 to 9, the method comprising the following steps: (1) Based on the total weight of the phenolic resin being 100 wt %, 10-40 wt % of a phenolic resin curing agent is heated and melted, and then a stress modifier is added, stirred, cooled and crushed to obtain an intermediate; (2) mixing the intermediate obtained in step (1), epoxy resin, inorganic filler, coupling agent, curing accelerator, tackifier, ion trap, release agent, colorant and remaining phenolic resin using a mixer; (3) Extruding, cooling, crushing and molding the high-mix material obtained in step (2) to obtain an epoxy resin molding material.

11. The method according to claim 10, characterized in that In step (1), the heating temperature is 110-160° C.; In step (3), the extrusion equipment is a twin-screw extruder, and the extrusion temperature is 90-115°C; In step (3), the molding equipment is a pressure pancake maker.

12. Use of the epoxy resin molding material according to any one of claims 1 to 9 and the epoxy resin molding material prepared by the method according to claim 10 as a power device packaging material.

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