Epoxy resin composition and preparation method thereof

Abstract

The invention relates to the technical field of high polymer materials, in particular to an epoxy resin composition and a preparation method thereof. The epoxy resin composition comprises the following raw materials: epoxy resin, a curing agent, a curing accelerator, a cycloolefin polymer, a coupling agent, a release agent, a coloring agent, a surface modifier and an inorganic filler. According to the epoxy resin composition, the surface modifier and the cycloolefin polymer are added, so that the dispersing performance of the filler is improved, agglomeration of the filler in the epoxy resin composition is prevented, good filler treatment is realized, the water absorption performance is reduced, and increase of water absorption paths in the epoxy resin composition caused by filler agglomeration is reduced; meanwhile, the cycloolefin polymer has the characteristics of low dielectric constant and dielectric loss, so that ion movement can be prevented and reduced under high-temperature and high-humidity conditions, the durability is excellent, the uniformity of the epoxy resin composition is improved, and the service life is prolonged. Further, the epoxy resin composition which is stable in performance, low in water absorption rate, excellent in high-temperature and high-humidity resistance and relatively good in continuous die processability is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and specifically, to an epoxy resin composition and a preparation method thereof. Background Art

[0002] Epoxy resin compositions are thermosetting materials widely used in the field of electronic packaging, mainly for encapsulating and protecting semiconductor devices such as integrated circuits, diodes, transistors, etc. With their excellent electrical properties, mechanical properties, heat resistance, and chemical stability, they can effectively protect chips from the influence of the external environment such as moisture, dust, and mechanical shock, making epoxy resin compositions one of the key electronic materials for encapsulating integrated circuits, ultra-large-scale, and ultra-thin integrated circuits.

[0003] Existing epoxy resin compositions, such as a low-hydroxyl phosphorus-containing epoxy resin and a composition for copper clad laminates and its preparation method disclosed in CN109438673B, by selecting a phenolic resin with a flexible hydrophobic skeleton structure and adding a large amount of fillers, reduce the water absorption rate of the epoxy resin composition, thereby reducing the vapor pressure during the reflow soldering process. At the same time, the bonding strength of the epoxy resin composition to the metal frame is improved, and the cracking resistance and PCT performance of the material are enhanced. However, this method of adding a large amount of fillers, although achieving the purpose of improving bonding and reducing water absorption, due to the excessive filler content, the fillers are prone to agglomeration, resulting in poor coating performance between the resin and the fillers. During the molding encapsulation process, when opening the mold, the strength is low, and the continuous model processing performance is poor. Summary of the Invention

[0004] The purpose of the present invention is to avoid the problem of poor coating performance between the resin and the fillers caused by filler agglomeration on the premise of ensuring the reliable performance of low water absorption of the epoxy resin composition.

[0005] The purpose of the present invention is to provide an epoxy resin composition and a preparation method thereof. On the premise of reducing the water absorption performance, by improving the dispersion performance of the fillers, preventing the agglomeration of the fillers in the epoxy resin composition, and ensuring the coating performance between the resin and the fillers.

[0006] To achieve the above object, one of the objects of the present invention is to provide an epoxy resin composition, comprising raw materials in the following mass percentages: Epoxy resin 1 - 15%, curing agent 1 - 15%, curing accelerator 0.01 - 2%, cycloolefin polymer 0.01 - 1%, coupling agent 0 - 5%, release agent 0.1 - 5%, colorant 0.1 - 5%, surface modifier 0.01 - 1%, and the balance is inorganic filler; The surface modifier is .

[0007] As a further improvement of the present technical solution, the ratio of the epoxy equivalent in the epoxy resin to the hydroxyl equivalent in the phenolic resin is 0.5 - 1.5:1.

[0008] As a further improvement of the present technical solution, the mass proportion of the epoxy resin in the epoxy resin composition is 2 - 10%.

[0009] As a further improvement of the present technical solution, the mass proportion of the curing agent in the epoxy resin composition is 2 - 10%.

[0010] As a further improvement of the present technical solution, the glass transition temperature of the cycloolefin polymer is less than 150 °C.

[0011] As a further improvement of the present technical solution, the mass proportion of the cycloolefin polymer in the epoxy resin composition is 0.01 - 0.7%.

[0012] As a further improvement of the present technical solution, the mass proportion of the surface modifier in the epoxy resin composition is 0.01 - 0.5%.

[0013] The second object of the present invention is to further provide a preparation method for preparing the above-mentioned epoxy resin composition, comprising the following steps: Step S1: Weigh the raw materials according to the mass ratio. Step S2: At room temperature, add the epoxy resin into the reaction kettle and stir until the epoxy resin is completely melted. After the material temperature is stable, add the cycloolefin polymer, continue to heat and stir until the cycloolefin polymer is uniformly dispersed in the melted resin, continue to stir for 30 - 60 min until completely uniformly mixed, then cool and discharge the material, and pulverize it for standby after cooling. Step S3: According to the ratio, put the inorganic filler into a high-speed mixer and stir until uniform. Then add the surface modifier and stir evenly, then add the coupling agent, release agent, and coloring agent, continue to stir until uniform, add the curing agent, pre-dispersed epoxy olefin polymer, and curing accelerator and stir evenly. Step S4: Knead and calender the stirred product in Step S3, then cool and pulverize it to a suitable particle size to obtain a powdery epoxy resin composition.

[0014] As a further improvement of the present technical solution, Step S2 is carried out in a reaction kettle with nitrogen protection.

[0015] As a further improvement of the present technical solution, in Step S4, the stirred product in Step S3 is put into an extruder, hot roll or kneader for kneading and calendering.

[0016] In the present invention, by adding a surface modifier, the dispersion performance of the filler is improved, agglomeration of the filler in the epoxy resin composition is prevented, good filler treatment is achieved, the water absorption performance is reduced, the increase in the water absorption path in the epoxy resin composition caused by filler agglomeration is reduced, and by performing high-temperature melting of the cycloolefin polymer and the epoxy / curing agent, molecular-level dispersion is achieved, the uniformity of the epoxy resin composition is improved, and thus an epoxy resin composition with better continuous molding processing performance is obtained.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: In the epoxy resin composition and its preparation method, by adding a surface modifier and a cycloolefin polymer, the dispersion performance of the filler is improved, agglomeration of the filler in the epoxy resin composition is prevented, good filler treatment is achieved, the water absorption performance is reduced, the increase in the water absorption path in the epoxy resin composition caused by filler agglomeration is reduced, and at the same time, due to the characteristics of the cycloolefin polymer having a low dielectric constant and dielectric loss, it can prevent and reduce ion movement under high-temperature and high-humidity conditions, has excellent durability, improves the uniformity of the epoxy resin composition, and thus an epoxy resin composition with stable performance, low water absorption rate, excellent high-temperature and high-humidity resistance, and good continuous molding processing performance is obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a flowchart of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] With ultra-thin very large-scale integrated circuits being the mainstream in the mid- to high-end market, under the condition that the packaging process and the market are becoming increasingly mature, the competition is also becoming increasingly fierce. Not only is it required that the epoxy molding compound meet the MSL reliability requirements of the JEDEC standard, but also PCT (Pressure Cooker Test), as a commonly used reliability test method for evaluating the performance stability of materials in high-temperature and high-humidity environments, together with tests such as HAST (High Accelerated Stress Test) and TCT (Thermal Cycle Test), has become a necessary test item in the industry to further evaluate the sealing performance and aging performance of products and ensure the competitiveness of products in the market.

[0021] PCT (Pressure Cooker Test) is an important test method for evaluating the reliability of materials in high-temperature and high-humidity environments. The main reasons for the failure of epoxy molding compounds (EMC) in PCT tests are as follows: Epoxy molding compounds absorb moisture in high-humidity environments, causing the material to expand and generate internal stress. When the moisture absorption exceeds a certain limit, delamination may occur at the interfaces between the material and the chip, lead frame, etc. This further damages the mechanical integrity and electrical properties of the material; In high-temperature and high-humidity environments, mobile ions (such as Na⁺, Cl⁻) in the material will migrate along the direction of the electric field, resulting in an increase in leakage current or device short circuit. This ion migration will seriously affect the electrical performance and reliability of the device, as well as delamination or electrical failure caused by process defects such as pores or incomplete curing.

[0022] There are the following two technical solutions in the prior art: Solution 1: By selecting epoxy resins or phenolic resins with a flexible hydrophobic backbone structure and adding a large amount of fillers, the water absorption rate of the epoxy resin composition is reduced, thereby reducing the vapor pressure during the reflow soldering process. At the same time, the bonding strength of the epoxy resin composition to the metal frame is improved, and the crack resistance and PCT performance of the material are enhanced.

[0023] The disadvantages of this solution are that due to the too high filler content, the coating performance between the resin and the filler is poor; the resin with a flexible backbone structure is relatively expensive, resulting in a high cost. In addition, during the molding and encapsulation process, when opening the mold, the strength is low, and the continuous model processing performance is poor.

[0024] Solution 2: Select a compound containing hydrotalcite or a layer-like double hydroxide particle plasma scavenger such as carbonate to capture and neutralize the movement of halogen ions or inorganic acid ions generated by the epoxy resin when the epoxy resin composition is placed at high temperature, improving and enhancing the heat resistance and moisture resistance of the epoxy resin composition for semiconductor encapsulation, and reducing the deterioration of the bonding part.

[0025] The disadvantages of this solution are that when the raw material purity is insufficient or the water absorption rate of the epoxy resin composition is too high, a small amount of ion scavenger is not enough to capture the ion movement in a high-temperature and high-humidity environment, especially during the long-term and rigorous assessment of PCT for 168 hours. At this time, a large amount of ion scavenger needs to be added to achieve the corresponding effect. When the amount of ion scavenger added is too large, problems such as an increase in water absorption rate resulting in failure of the MSL assessment or a decrease in the continuous moldability of the epoxy resin composition are likely to occur. At the same time, since the ion scavenger is a nano-level material, how to improve its dispersion performance is also one of the current problems when the added amount is relatively large.

[0026] Therefore, one of the objectives of the present invention is to provide an epoxy resin composition, comprising raw materials in the following mass percentages: Epoxy resin 1 - 15%, curing agent 1 - 15%, curing accelerator 0.01 - 2%, cycloolefin polymer 0.01 - 1%, coupling agent 0 - 5%, release agent 0.1 - 5%, colorant 0.1 - 5%, surface modifier 0.01 - 1%, and the balance being inorganic filler; The surface modifier is , which is of the X - 88 - 398 type, purchased from Shin - Etsu Chemical Co., Ltd. The chemical name of this surface modifier is 2,2 - dimethoxy - 1 - phenyl - 1 - aza - 2 - silacyclopentane, and the functional groups contained are amino (secondary) and phenyl (parent organic group).

[0027] Furthermore, the ratio of the epoxy equivalent in the epoxy resin to the hydroxyl equivalent in the phenolic resin is 0.5 - 1.5:1, and the mass percentage of the epoxy resin in the epoxy resin composition is preferably 2 - 10%.

[0028] Furthermore, the mass percentage of the curing agent in the epoxy resin composition is preferably 2 - 10%.

[0029] Still further, the mass percentage of the cycloolefin polymer in the epoxy resin composition is preferably 0.01 - 0.7%, and the glass transition temperature of the cycloolefin polymer is less than 150 °C, more preferably less than 100 °C.

[0030] Even further, the mass percentage of the surface modifier in the epoxy resin composition is preferably 0.01 - 0.5%.

[0031] Regarding the selection of epoxy resin in the present invention: On the premise of not affecting the effects of the present invention, the epoxy resin can be a general - purpose epoxy resin in the art, including the following epoxy resins: for example, phenol - novolac - type epoxy resins such as phenol - novolac epoxy resin and o - cresol - novolac epoxy resin, which are phenol - novolac epoxy resins of phenols and aldehydes; diglycidyl ethers such as bisphenol A, bisphenol F, bisphenol S, and alkyl - substituted bisphenol; glycidylamine - type epoxy resins obtained by reacting polyamines such as diaminodiphenylmethane and melamine with epichlorohydrin; linear aliphatic epoxy resins obtained by oxidizing olefin bonds with peroxyacids such as peracetic acid, and alicyclic epoxy resins; biphenyl - type epoxy resins and poly - aromatic - ring - type epoxy resins with excellent water absorption and adhesion properties, etc., can all be used on the premise of not affecting the performance of the present invention. Among them, from the viewpoints of fluidity and reflow soldering resistance, biphenyl - type epoxy resins are preferred; from the viewpoint of reducing water absorption, dicyclopentadiene - type epoxy resins can be selected.

[0032] Selection of curing agent in the present invention: On the premise of not affecting the effect of the present invention, the curing agent can be a commonly used phenolic resin-based curing agent in the art. For example: phenol-arylalkyl resins synthesized by reacting phenols such as phenol, cresol, resorcinol, catechol, bisphenol A, bisphenol F, phenylphenol, aminophenol, etc. and / or naphthols, and dimethoxyp-xylene or bis(methoxymethyl)biphenyl; biphenyl-type phenol-arylalkyl resins; naphthol-arylalkyl resins; dicyclopentadiene-type phenolic novolak epoxy resins synthesized by copolymerizing phenols and / or naphthols with dicyclopentadiene, dicyclopentadiene-type naphthol phenolic novolak epoxy resins and other dicyclopentadiene-type phenolic resins; triphenylmethane-type phenolic resins; terpene-modified phenolic resins; p-xylene and / or m-xylene-modified phenolic resins; melamine-modified phenolic resins; dicyclopentadiene-modified phenolic phenolic resins; and phenolic resins obtained by copolymerizing two or more of them, etc.

[0033] Selection of curing accelerator in the present invention: There is no special requirement for the curing accelerator. Any known curing accelerator for epoxy resin compositions can be used. Commonly used tertiary amine compounds; imidazole compounds, including 2-methylimidazole, 2-phenylimidazole, 2-methyl-4-ethylimidazole, etc.; quaternary ammonium salts; organometallic salts; phosphorus compounds, such as triphenylphosphine, tributylphosphine, adducts of triphenylphosphine and benzoquinone, tetraphenylboric acid, tetraphenylphosphonium, triphenylphosphine triphenylborane, etc.; diazabicycloolefins, etc. These compounds and their derivatives can be used alone or in combination.

[0034] Selection of inorganic filler in the present invention: The inorganic filler is a filling component in the epoxy resin composition. Any known inorganic filler used in epoxy resins in the prior art solutions can be used, such as fused silica, crystalline silica, alumina, aluminum nitride, boron nitride, oxidized state, glass fiber, calcium carbonate, calcium silicate, barium titanate, etc. As the inorganic filler, spherical and fused silica with an average particle size of 3-30 microns are mainly preferred.

[0035] Selection of coupling agent in the present invention: In order to enhance the bonding strength between the inorganic filler and the resin, a known silane coupling agent or titanate coupling agent in the prior art can be selected to pretreat the surface of the inorganic filler. For example: γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-ureidopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-isocyanatopropyltriethoxysilane, etc. can be used alone or in combination.

[0036] Selection of release agent in the present invention: For the epoxy resin composition described in the present invention, there is no particular limitation on the release agent, and natural or synthetic waxes known in the art can be selected as the release agent. For example, beeswax, carnauba wax, polyethylene wax, montan wax, rice wax, saponified montan wax, stearic acid, stearate, zinc stearate, etc.

[0037] In the present invention, the colorant can be selected as carbon black, titanium oxide, iron oxide red, etc., and for the epoxy resin composition described in the present invention, if necessary, in addition to the above components, a flame retardant can also be included, such as aluminum hydroxide, magnesium hydroxide, zinc borate, zinc molybdate, melamine, etc., so as to achieve the effect of environmental protection and flame retardancy.

[0038] Please refer to Figure 1 As shown, the second object of the present invention is to also provide a preparation method for preparing the above-mentioned epoxy resin composition, and the specific steps are as follows: Step S1: Weigh the raw materials according to the mass ratio. Step S2: At room temperature, add the epoxy resin to the reaction kettle and stir until the epoxy resin is completely melted. After the material temperature is stable, add the cycloolefin polymer, continue to heat and stir until the cycloolefin polymer is completely and evenly dispersed in the melted resin, continue to stir for 30 - 60 min until completely and evenly mixed, then cool and discharge, and pulverize for standby after cooling. Here, to reduce resin oxidation, it is preferably prepared in a reaction kettle with nitrogen protection. Step S3: According to the ratio, put the inorganic filler into a high-speed mixer and stir until uniform, set the rotation speed and stirring time as needed, with the criterion of being stirred evenly; Then add the surface modifier and stir evenly, then add the coupling agent, release agent, and colorant, continue to stir until uniform, add the curing agent, pre-dispersed epoxy olefin polymer, and curing accelerator and stir evenly; Step S4: Put the stirring product in step S3 into an extruder, hot roll or kneader for kneading and calendering, then cool and pulverize to a suitable particle size to obtain a powdery epoxy resin composition.

[0039] The following specific examples are used to further illustrate an epoxy resin composition and its preparation method provided by the present invention. Example 1

[0040] Step S1: Weigh 6.57% of epoxy resin, 4.38% of curing agent, 0.18% of curing accelerator, 0.1% of cycloolefin polymer, 0.12% of coupling agent, 0.25% of release agent, 0.2% of colorant, 0.2% of surface modifier according to the mass ratio, and the balance is inorganic filler; Among them, the surface modifier is ; Step S2: At room temperature, add epoxy resin into a reaction kettle with nitrogen protection and stir until the epoxy resin is completely melted. After the material temperature is stable, add cycloolefin polymer, continue heating and stirring until the cycloolefin polymer is completely and evenly dispersed in the molten resin, continue stirring for 30 - 60 min until completely and evenly mixed, then cool and discharge the material, and pulverize it after cooling for standby; Step S3: According to the ratio, put the inorganic filler into a high-speed mixer and stir until it is uniform. Set the rotation speed and stirring time as required, with the criterion of being stirred evenly; Then add the surface modifier and stir evenly, then add the coupling agent, release agent and colorant, continue stirring until it is uniform, add the curing agent, pre-dispersed epoxy olefin polymer and curing accelerator and stir evenly; Step S4: Put the stirring product in step S3 into an extruder, hot roll or kneader for kneading and calendering, then cool and pulverize it to a suitable particle size to obtain a powdery epoxy resin composition.

[0041] In this embodiment, other materials such as epoxy resin use polyaromatic ring type epoxy resin NC - 3000L, purchased from Nippon Kayaku Co., Ltd.; The curing agent uses polyaromatic ring type phenolic resin MEH - 7851SS, purchased from Meiwa Plastics Ind., Ltd.; The curing accelerator uses triphenylphosphine - 1,4 - benzoquinone adduct, purchased from Nanjing Lanbian Biochemical Technology Co., Ltd.; The inorganic filler uses silica powder NQ1250D, purchased from Jiangsu Lianrui New Materials Co., Ltd.; The coupling agent uses γ - mercaptopropyltriethoxysilane KH580, purchased from Jiangxi Chenguang New Materials Co., Ltd.; The release agent uses paraffin wax, purchased from Clariant; The cycloolefin polymer uses TOPAS 8007S - 04, purchased from Polyplastics Co., Ltd.; The colorant uses carbon black JY 2021, purchased from Sichuan Zhenghao Special Carbon Black Technology Co., Ltd.; Example 2

[0042] Step S1: Weigh 6.45% of epoxy resin, 4.3% of curing agent, 0.18% of curing accelerator, 0.3% of cycloolefin polymer, 0.12% of coupling agent, 0.25% of release agent, 0.2% of colorant, 0.2% of surface modifier according to the mass ratio, and the balance is inorganic filler; Among them, the surface modifier is ; Step S2: At room temperature, add epoxy resin into a reaction kettle with nitrogen protection and stir until the epoxy resin is completely melted. After the material temperature is stable, add cycloolefin polymer, continue to heat and stir until the cycloolefin polymer is completely and evenly dispersed in the melted resin, continue to stir for 30 - 60 min until completely and evenly mixed, then cool and discharge the material, and crush it for standby after cooling; Step S3: According to the ratio, put the inorganic filler into a high-speed mixer and stir until it is uniform. Set the rotation speed and stirring time as needed, with the criterion of being stirred evenly; Then add the surface modifier and stir evenly, then add the coupling agent, release agent, and coloring agent, continue to stir until it is uniform, add the curing agent, pre-dispersed epoxy olefin polymer, and curing accelerator and stir evenly; Step S4: Put the stirred product in Step S3 into an extruder, hot roll or kneader for kneading and calendering, then cool and crush it to a suitable particle size to obtain a powdery epoxy resin composition.

[0043] In this embodiment, the materials such as epoxy resin and curing agent are the same as those in Embodiment 1, and will not be elaborated in this embodiment. Embodiment 3

[0044] Step S1: Weigh 5.73% of epoxy resin, 3.82% of curing agent, 0.18% of curing accelerator, 1.5% of cycloolefin polymer, 0.12% of coupling agent, 0.25% of release agent, 0.2% of coloring agent, 0.2% of surface modifier according to the mass ratio, and the balance is inorganic filler; Among them, the surface modifier is ; Step S2: At room temperature, add epoxy resin into a reaction kettle with nitrogen protection and stir until the epoxy resin is completely melted. After the material temperature is stable, add cycloolefin polymer, continue to heat and stir until the cycloolefin polymer is completely and evenly dispersed in the melted resin, continue to stir for 30 - 60 min until completely and evenly mixed, then cool and discharge the material, and crush it for standby after cooling; Step S3: According to the ratio, put the inorganic filler into a high-speed mixer and stir until it is uniform. Set the rotation speed and stirring time as needed, with the criterion of being stirred evenly; Then add the surface modifier and stir evenly, then add the coupling agent, release agent, and coloring agent, continue to stir until it is uniform, add the curing agent, pre-dispersed epoxy olefin polymer, and curing accelerator and stir evenly; Step S4: Put the stirred product in Step S3 into an extruder, hot roll or kneader for kneading and calendering, then cool and crush it to a suitable particle size to obtain a powdery epoxy resin composition.

[0045] In this embodiment, the materials such as epoxy resin and curing agent are the same as those in Embodiment 1, and will not be elaborated in this embodiment. Example 4

[0046] In this example, the surface modifier was replaced and the cycloolefin polymer was cancelled, specifically as follows: Step S1: Weigh 6.63% of epoxy resin, 4.42% of curing agent, 0.18% of curing accelerator, 0.12% of coupling agent, 0.25% of demolding agent, 0.2% of colorant, and 0.2% of surface modifier according to the mass ratio, and the balance is inorganic filler; Among them, the surface modifier is ; Step S2: At room temperature, add the epoxy resin to a reaction kettle with nitrogen protection and stir until the epoxy resin is completely melted, then cool and discharge, and crush it for standby after cooling; Step S3: According to the ratio, put the inorganic filler into a high-speed mixer and stir until it is uniform. Set the rotation speed and stirring time as required to ensure uniform stirring; Then add the surface modifier and stir evenly, then add the coupling agent, demolding agent, and colorant, continue to stir until uniform, add the curing agent, pre-dispersed epoxy olefin polymer, and curing accelerator and stir evenly; Step S4: Put the stirring product in Step S3 into an extruder, hot roll or kneader for kneading and calendering, then cool and crush it to a suitable particle size to obtain a powdery epoxy resin composition.

[0047] In this example, the surface modifier is , and this surface modifier is of the KBM-573 type, also purchased from Shin-Etsu Chemical Co., Ltd. The chemical name of this modifier is N-phenyl-3-aminopropyltrimethoxysilane, and the CAS number is 3068-76-6. It is a silane coupling agent with an aniline structure as the organic functional group, and its functional group is an amino group.

[0048] Other materials such as epoxy resin and curing agent are the same as those in Example 1, and will not be elaborated in this example.

[0049] In Examples 1-4, the components and mass ratios are shown in Table 1: Table 1: Components and mass ratios in Examples 1-4

[0050] The following detection tests were carried out on the epoxy resin compositions prepared in Examples 1-4: Gel time (GT) test: Determine the gelation time (s) according to Article 6.1 of "GB / T 40564-2021 Test Methods for Epoxy Molding Compounds for Electronic Packaging".

[0051] Flow length (SF) test: The flow distance (cm) was measured according to the spiral flow length in Article 6.2 of "Test Methods for Epoxy Molding Compounds for Electronic Packaging - GB / T 40564-2021".

[0052] Reliability / MSL1 test: Use epoxy molding compound on the MGP molding die to encapsulate the products of SOD523 chips. After encapsulation, post-cure (175 °C * 6 h). After electroplating, printing, and lead frame cutting, place the encapsulated body in a humidity chamber at 85 °C / 85% relative humidity for moisture absorption for 168 h. After moisture absorption, perform reflow soldering at 260 °C three times, which is the MSL1 test. After completion, use C-SAM for scanning to observe the delamination situation. Pass the assessment if there is no delamination.

[0053] PCT electrical performance test: For products that have passed the MSL1 and delamination scanning, perform electrical performance tests after PCT for 96 h. Excessive leakage current, short circuit, and open circuit are all considered failures.

[0054] Continuous operability test: Use epoxy molding compound on the MGP molding die to encapsulate the products of SOD523 chips and perform continuous encapsulation until the frame is deformed or the mold is dirty and needs to be cleaned. The number of encapsulations during this period is the continuous moldability of production.

[0055] Record the above test results in Table 2.

[0056] Table 2: Comparison of test results of epoxy resin compositions prepared in Examples 1-4

[0057] It can be seen from Table 2 that the gel time of the epoxy resin compositions prepared in Examples 1-4 is 25-27 s, the flow length is 90-113 cm, and the continuous moldability of 300 molds is normal, indicating that the epoxy resin compositions prepared by the present invention have relatively high strength and good continuous mold processing performance.

[0058] Specifically, in the epoxy resin composition for semiconductor packaging in the present invention, by adding the X-88-398 type surface modifier, the dispersion performance of the filler is improved, the agglomeration of the filler in the epoxy resin composition is prevented, good filler treatment is achieved, the water absorption performance is reduced, and the increase in the water absorption path in the epoxy resin composition caused by filler agglomeration is reduced, thereby reducing the failure risk during the MSL and PCT assessments; Meanwhile, after the X-88-398 type surface modifier reacts with silica powder, it can still play the role of coupling and treating silica powder, and at the same time, it will not introduce other non-reactive small molecule substances, reducing the volatility of the epoxy resin composition and the risk of molecular and ionic movement during the high-temperature and high-humidity assessment process, which is beneficial to improving the reliable performance and high-temperature and high-humidity performance. The reaction process of the X-88-398 type surface modifier and silica powder (the component is silicon dioxide SiO2) is as follows: ; The structure of the X-88-398 type surface modifier is: , this structure has an active group of phenylamino, and the presence of nitrogen atoms plays a promoting role in enhancing the adhesion between the resin composition and the encapsulation material.

[0059] In addition, due to its low polarity, cycloolefin polymer has low moisture absorption and low water permeability, which can reduce the water absorption rate of the epoxy resin composition. At the same time, due to its characteristics of low dielectric constant and dielectric loss, it has the characteristics of preventing and reducing ion movement under high-temperature and high-humidity conditions and excellent durability.

[0060] Through verification and screening, the present invention uses a polyolefin polymer with a relatively low Tg suitable for processing and molding, adjusts its dosage, and at the same time, through high-temperature melting with epoxy / curing agent, achieves molecular-level dispersion, improves the uniformity of the epoxy resin composition, and further obtains an epoxy resin composition with stable performance, low water absorption rate, and excellent high-temperature and high-humidity performance.

[0061] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions in the specification are only preferred examples of the present invention and do not limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements fall within the scope of the present invention claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an epoxy resin composition, characterized in that, It includes the following steps: Step S1: Weigh 1-15% of epoxy resin, 1-15% of curing agent, 0.01-2% of curing accelerator, 0.01-1% of cycloolefin polymer, 0-5% of coupling agent, 0.1-5% of release agent, 0.1-5% of colorant, 0.01-1% of surface modifier according to mass ratio, and the balance is inorganic filler; Among them, the surface modifier is ; Step S2: At room temperature, add epoxy resin into the reaction kettle and stir until the epoxy resin is completely melted. After the material temperature is stable, add cycloolefin polymer, continue to heat and stir until the cycloolefin polymer is uniformly dispersed in the melted resin, continue to stir for 30-60 min until completely and uniformly mixed, then cool and discharge, and pulverize for standby after cooling; Step S3: Put the inorganic filler into a high-speed mixer according to the ratio and stir until uniform; Then add the surface modifier and stir evenly, then add the coupling agent, release agent and colorant, continue to stir until uniform, add the curing agent, pre-dispersed epoxy olefin polymer and curing accelerator and stir evenly; Step S4: Knead and calender the stirring product in Step S2, then cool and pulverize to obtain a powdery epoxy resin composition.

2. The method for preparing an epoxy resin composition according to claim 1, characterized in that: In the said Step S1, the ratio of the epoxy equivalent in the epoxy resin to the hydroxyl equivalent in the phenolic resin is 0.5-1.5:

1.

3. The method for preparing an epoxy resin composition according to claim 1, characterized in that: In the said Step S1, the mass proportion of the epoxy resin in the epoxy resin composition is 2-10%.

4. The method for preparing an epoxy resin composition according to claim 1, characterized in that: In the said Step S1, the mass proportion of the curing agent in the epoxy resin composition is 2-10%.

5. The method for preparing an epoxy resin composition according to claim 1, characterized in that: In the said Step S1, the glass transition temperature of the cycloolefin polymer is less than 150 °C.

6. The method for preparing an epoxy resin composition according to claim 1, characterized in that: In the said Step S1, the mass proportion of the cycloolefin polymer in the epoxy resin composition is 0.01-0.7%.

7. The method for preparing an epoxy resin composition according to claim 1, characterized in that: In the said Step S1, the mass proportion of the surface modifier in the epoxy resin composition is 0.01-0.5%.

8. The method for preparing an epoxy resin composition according to claim 1, characterized in that: The said Step S2 is carried out in a reaction kettle with nitrogen protection.

9. The method for preparing an epoxy resin composition according to claim 1, characterized in that: In the said Step S4, the stirring product in Step S3 is put into an extruder, a hot roll or a kneader for kneading and calendering.

10. An epoxy resin composition prepared by the preparation method according to any one of claims 1-9.

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