Epoxy molding compound with low shrinkage and high heat resistance and preparation method thereof

Abstract

The invention relates to the technical field of epoxy molding compounds, in particular to a low-shrinkage and high-heat-resistance epoxy molding compound and a preparation method thereof. The low-shrinkage and high-heat-resistance epoxy molding compound is prepared from the following raw materials in parts by weight: 6 to 8 parts of epoxy resin, 3 to 7 parts of phenolic resin, 80 to 90 parts of filler, 0.6 to 1 part of modifier, 0.1 to 0.5 part of accelerant, 0.2 to 0.4 part of coupling agent, 0.3 to 0.8 part of flexibilizer, 0.2 to 0.4 part of release agent, 0.2 to 0.4 part of coloring agent and 0.3 to 0.5 part of flame retardant, the modifier is a mixture of 1-phenyl-5-mercaptotetrazole and 5-aminotetrazole according to a weight ratio of 5: (1 to 5); the prepared epoxy molding compound has the characteristics of low shrinkage and high heat resistance.

Description

Technical Field

[0001] The invention relates to the technical field of epoxy molding compounds, and in particular to a low-shrinkage and high-heat-resistant epoxy molding compound and a preparation method thereof. Background Art

[0002] Epoxy molding compound (EMC) is mainly composed of fillers, resins, hardeners, accelerators, coupling agents, release agents and other components. It is widely used in the semiconductor packaging industry due to its excellent mechanical properties and processing formability. With the integration and modularization of the semiconductor packaging industry, the demand for large-size, high-density and ultra-thin packaging is becoming increasingly widespread, and more stringent requirements are placed on the warpage of products. Shrinkage rate is an important reference for measuring warpage performance. At the same time, the widespread popularization of third-generation semiconductor technology also puts forward new requirements for the heat resistance of packaging materials.

[0003] The shrinkage of EMC during the processing and molding process mainly comes from two aspects. One is the chemical shrinkage generated during the curing process. The shrinkage at this stage is caused by the increase in cross-linking density. The other is thermal shrinkage, which occurs during the cooling stage from high-temperature curing to room temperature. Generally speaking, when EMC with high curing shrinkage is used for packaging, residual stress may appear after curing, and the product is prone to warping, deformation, and even cracking. At the same time, as the heat-resistant temperature of the material increases, the modulus increases during high-temperature molding, which further increases the material stress and the risk of warping. Therefore, it is necessary to reasonably optimize the anti-shrinkage performance and modulus of EMC while ensuring high heat resistance. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a low-shrinkage and high-heat-resistant epoxy molding compound and a preparation method thereof, so as to solve the stress release and warping problems faced by high-heat-resistant EMC for third-generation semiconductor packaging.

[0005] Based on the above purpose, the present invention provides a low-shrinkage and high-heat-resistant epoxy molding compound, which is prepared from the following raw materials, by weight: 4-8 parts of epoxy resin, 3-7 parts of phenolic resin, 80-90 parts of filler, 0.6-1 part of modifier, 0.05-0.5 part of accelerator, 0.2-0.4 part of coupling agent, 0.3-0.8 part of toughening agent, 0.2-0.4 part of release agent, 0.2-0.4 part of colorant and 0.3-0.5 part of flame retardant.

[0006] Furthermore, the modifier is a mixture of 1-phenyl-5-mercaptotetrazole and 5-aminotetrazole in a weight ratio of 5:1-5.

[0007] Furthermore, the epoxy resin is an imide-modified bisphenol epoxy resin, a mixture of a bisphenol epoxy resin and a tri-polyfunctional epoxy resin in a weight ratio of 2:2-3:2-3.

[0008] Furthermore, the structural formula of the imide-modified bisphenol epoxy resin is as follows:

[0009]

[0010] Preferably, the bisphenol epoxy resin is bisphenol A or bisphenol F epoxy resin.

[0011] Preferably, the phenolic resin is phenolic resin.

[0012] Preferably, the filler is one or a mixture of crystalline silica and fused silica.

[0013] Preferably, the accelerator is one or a mixture of several of an imidazole accelerator, a phosphorus accelerator and an amine accelerator.

[0014] Preferably, the coupling agent is one or a mixture of epoxy silane coupling agent, mercapto silane coupling agent, amino silane coupling agent and methyl methoxy silane coupling agent.

[0015] Preferably, the toughening agent is epoxy and polyether double-barreled functional group modified silicone oil.

[0016] Preferably, the release agent is a mixture of one or more of polyethylene wax, oxidized polyethylene wax and palm wax.

[0017] Preferably, the colorant is carbon black and the flame retardant is aluminum hydroxide.

[0018] Furthermore, the present invention also provides a method for preparing a low-shrinkage and high-heat-resistant epoxy molding compound, comprising the following steps: after mixing the raw materials, melting and kneading them evenly on an open rubber mixer, removing the evenly mixed materials from the open rubber mixer, naturally cooling and crushing them to obtain powdery materials, and preforming them into cake materials to obtain low-shrinkage and high-heat-resistant epoxy molding compound.

[0019] Beneficial effects of the present invention: The epoxy molding compound of the present invention can be applied to the third generation semiconductor packaging. By introducing the resin structure of imide-modified bisphenol epoxy resin with special rigidity, the molecular rotation is inhibited, the curing shrinkage is reduced, and the heat resistance and reliability are improved. Secondly, the innovative introduction of azole compounds as modifiers promotes the improvement of material strength and toughness through the coordinated regulation of two structures of azole compounds, without causing a great negative impact on the glass transition temperature of the material. Finally, because the optimized ratio of tri-multifunctional resin and promoter increases the cross-linking density of the material, the heat resistance temperature is further improved. The epoxy molding compound prepared by the above three methods has the characteristics of low shrinkage and high heat resistance. DETAILED DESCRIPTION

[0020] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0021] The sources of the raw materials used in the embodiments and comparative examples are as follows:

[0022] Epoxy resin: bisphenol A type epoxy resin (Mitsubishi Chemical Corporation, YX4000H), imide modified bisphenol type epoxy resin (Shanghai Ruiyinna Electronic Materials Co., Ltd., BES1-9517), tripolyfunctional epoxy resin (Nippon Kayaku Co., Ltd., EPPN-501H), o-cresol type epoxy resin (Nanya Electronic Materials Kunshan Co., Ltd., NPCN-702).

[0023] Phenolic resin: phenol phenolic resin (Shandong Shengquan Chemical Co., Ltd.).

[0024] Inorganic filler: molten silicon powder (NQ1130 from Jiangsu Lianrui New Materials Co., Ltd.), crystalline silicon powder (CR35 from Jiangsu Zhongteng Quartz Materials Technology Co., Ltd.).

[0025] Toughening agent: epoxy and polyether bifunctional modified silicone oil (BES5-2130 produced by Ruiyinna Electronic Materials (Shanghai) Co., Ltd.).

[0026] Modifiers: 1-phenyl-5-mercaptotetrazole (Shanghai MacLean Biochemical Technology Co., Ltd.), 5-aminotetrazole (Shanghai MacLean Biochemical Technology Co., Ltd.).

[0027] Curing accelerator: imidazole accelerator (2MZ-A from Shikoku Chemical Industry Co., Ltd.), phosphorus accelerator (TPP-BQ from Shanghai Huichuang Trading Co., Ltd.).

[0028] Coupling agent: epoxy silane coupling agent (Shandong Chenguang Silane Coupling Agent Co., Ltd., CG-O187).

[0029] Colorant: Carbon black (Mitsubishi Chemical Corporation, MA-600).

[0030] Release agent: polyethylene wax (Clariant, Germany, Licowax E PED).

[0031] Flame retardant: aluminum hydroxide (Ningbo Sumeitong Trading Co., Ltd., FR-3810-C).

[0032] The preparation methods of Examples 1-3 and Comparative Examples 1-5 are as follows:

[0033] After weighing and mixing the ingredients according to the proportions in Table 1, the ingredients are melted and mixed evenly on an open rubber mixer. The evenly mixed materials are removed from the open rubber mixer, cooled naturally, and crushed to obtain powdery materials, which are preformed into cake materials to obtain epoxy molding compounds.

[0034] Table 1 Recipe

[0035]

[0036]

[0037] Performance Test:

[0038] Spiral flow length: Take 15g of the epoxy resin composition sample to be tested and inject it into the EMMI-1-66 spiral flow metal mold on the transfer molding press to measure the spiral flow length of the sample. The mold temperature is 175±2℃, the molding pressure is 7.0±0.2MPa, and the holding time is 120s. Then take the sample out of the metal mold and read the spiral flow length in cm. The results are shown in Table 2 (GB / T 40564-2021)

[0039] Gelation time: hot plate method, heat the hot plate to 175℃±1℃, take 0.5g of epoxy resin composition sample and place it on the hot plate, and immediately spread it flat with a tongue depressor to an area of ​​about 5cm 2 , start timing when melting begins, use a tongue depressor to push the powder at a frequency of 1 time / second, and the end point is when the powder gradually changes from a fluid to a gel state. Read the time taken in seconds. The results are shown in Table 2. (GB / T 40564-2021)

[0040] PCT water absorption rate: A high temperature and high pressure cooking tester was used, the test conditions were 121°C, 0.2Mpa, and the sample size was 50mm in diameter × 3mm in height. The results are shown in Table 2.

[0041] Bending strength and bending modulus: The epoxy resin composition was molded using a low-pressure transfer molding machine at a mold temperature of 175°C. The sample size was 80×10×4mm. The curing time was 120s. The post-curing was then performed. The post-curing conditions were: 6h at 175°C. The bending strength (MPa) and bending modulus (GPa) of the post-cured specimens were tested using a universal testing machine. The results are shown in Table 2. (GB / T 40564-2021)

[0042] Glass transition temperature: tested by TMA probe method, the sample size is 5mm in diameter × 5mm in height, the probe applies a sample pressure of 0.05N, the test temperature range is 0-220℃, the heating rate is 10℃ / min, and the results are shown in Table 2. (GB / T40564-2021)

[0043] Shrinkage rate: Sample size is 120×15×10mm. After injection molding, cool to room temperature and test sample length Ls and cavity length Lm (GB / T 40564-2021)

[0044]

[0045] Warping: On a heating platform at 175°C, the epoxy molding compound was evenly scraped onto a 75×25×1mm slide glass with a coating thickness of 0.5mm. After curing and cooling, the height of one end of the test slide glass was the warping height. The results are shown in Table 2.

[0046] Table 2 Performance test results

[0047]

[0048]

[0049] Data Analysis:

[0050] As can be seen from the data of Examples 1-3 in Table 2, the epoxy molding compound prepared by the present invention has a higher glass transition temperature, indicating that it has higher heat resistance, and has high bending strength and low bending modulus, which improve the structural strength and impact resistance of the material, while giving it flexibility, adapting to slight deformation, reducing stress concentration, and reducing the risk of damage. Most importantly, the epoxy molding compound prepared by the present invention has a lower shrinkage and warping, which helps to maintain the dimensional stability and shape accuracy of the product, reduce the internal stress generated during processing and curing, and reduce the risk of deformation and cracking. The above characteristics ensure the reliability and performance consistency of the packaging components, especially in precision electronic devices, can effectively protect the internal structure and improve the overall quality and service life of the product.

[0051] It can be seen from the data of Example 1 and Comparative Example 1 in Table 2 that the introduction of imide-modified bisphenol epoxy resin can significantly reduce the shrinkage and warpage of the system, and due to the rigidity of the imide structure itself, the strength and glass transition temperature of the epoxy molding compound itself are further improved.

[0052] It can be seen from the data of Example 1 and Comparative Example 2 in Table 2 that 1-phenyl-5-mercaptotetrazole and 5-aminotetrazole synergistically regulate the flexural strength and flexural modulus of the epoxy molding compound, so that the epoxy molding compound has high flexural strength and low flexural modulus.

[0053] It can be seen from the data of Example 1 and Comparative Example 3 in Table 2 that the glass transition temperature can be effectively increased by introducing a tri-multifunctional epoxy resin, which is mainly due to the increase in cross-linking density.

[0054] It can be seen from the data of Example 1 and Comparative Example 4 in Table 2 that 1-phenyl-5-mercaptotetrazole can effectively improve the bending strength of the epoxy molding compound, which is mainly due to the introduction of benzene rings and the cross-linking effect of mercapto groups.

[0055] It can be seen from the data of Example 1 and Comparative Example 5 in Table 2 that 5-aminotetrazole can effectively reduce the flexural modulus of the epoxy molding compound, which may be because aminotetrazole helps to adjust the flexibility of the polymer chain.

[0056] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A low shrinkage and high heat resistance epoxy molding compound, characterized in that: The invention is prepared from the following raw materials by weight: 6-8 parts of epoxy resin, 3-7 parts of phenolic resin, 80-90 parts of filler, 0.6-1 parts of modifier, 0.1-0.5 parts of accelerator, 0.2-0.4 parts of coupling agent, 0.3-0.8 parts of toughening agent, 0.2-0.4 parts of release agent, 0.2-0.4 parts of colorant and 0.3-0.5 parts of flame retardant; The modifier is a mixture of 1-phenyl-5-mercaptotetrazole and 5-aminotetrazole in a weight ratio of 5:1-5; The epoxy resin is an imide-modified bisphenol epoxy resin, a mixture of a bisphenol epoxy resin and a tri-polyfunctional epoxy resin in a weight ratio of 3:1-2:2-3; The structural formula of the imide-modified bisphenol epoxy resin is as follows:

2. The low shrinkage and high heat resistance epoxy molding compound according to claim 1, characterized in that: The bisphenol epoxy resin is bisphenol A or bisphenol F epoxy resin.

3. The low shrinkage and high heat resistance epoxy molding compound according to claim 1, characterized in that: The phenolic resin is phenolic resin.

4. The low shrinkage and high heat resistance epoxy molding compound according to claim 1, characterized in that: The filler is one of crystalline silica and fused silica or a mixture of both.

5. The low shrinkage and high heat resistance epoxy molding compound according to claim 1, characterized in that: The accelerator is one or a mixture of several of an imidazole accelerator, a phosphorus accelerator and an amine accelerator.

6. The low shrinkage and high heat resistance epoxy molding compound according to claim 1, characterized in that: The coupling agent is one or a mixture of epoxy silane coupling agent, mercapto silane coupling agent, amino silane coupling agent and methyl methoxy silane coupling agent.

7. The low shrinkage and high heat resistance epoxy molding compound according to claim 1, characterized in that: The toughening agent is epoxy and polyether double-barreled functional group modified silicone oil.

8. The low shrinkage and high heat resistance epoxy molding compound according to claim 1, characterized in that: The release agent is one or a mixture of polyethylene wax, oxidized polyethylene wax and palm wax.

9. The low shrinkage and high heat resistance epoxy molding compound according to claim 1, characterized in that: The colorant is carbon black, and the flame retardant is aluminum hydroxide.

10. A method for preparing a low-shrinkage and high-heat-resistant epoxy molding compound according to any one of claims 1 to 9, characterized in that: The following steps are involved: After the raw materials are mixed, they are melted and mixed evenly on an open rubber mixer, the evenly mixed materials are taken out of the open rubber mixer, naturally cooled, and crushed to obtain powdery materials, which are preformed into cake materials to obtain low-shrinkage and high-heat-resistant epoxy molding materials.

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