Low-temperature fast-curing powdery epoxy molding compound and preparation method thereof

Abstract

The invention relates to the technical field of electronic packaging, in particular to a low-temperature fast-curing powdery epoxy molding compound and a preparation method thereof.The low-temperature fast-curing powdery epoxy molding compound at least comprises epoxy resin, a curing agent, inorganic filler and a catalyst, the epoxy resin at least comprises epoxy resin shown in the formula (1) and the formula (2), the mass ratio of the epoxy resin shown in the formula (1) to the epoxy resin shown in the formula (2) is (3-5): (0.5-1.5), and the curing agent is a curing agent. A compression mold can be used for injection molding, and the injection molding requirement of thin packaging and the plastic packaging process requirement of low-temperature rapid curing are met.

Description

Technical Field

[0001] The invention relates to the technical field of electronic packaging, in particular to a low-temperature fast-curing powdery epoxy molding compound and a preparation method thereof. Background Art

[0002] In recent years, WLCSP (wafer-level chip packaging) and WLPLP (fan-out panel-level packaging) products have emerged in the packaging field, with a plastic packaging area of ​​600*600mm. 2 , accordingly, the control of warpage becomes a technical difficulty. From the perspective of the plastic encapsulation compound formula system, an effective way is to increase the amount of filler to reduce the thermal expansion coefficient, and use rubber stress modifiers such as silicone resin or silicone oil and low stress resin to reduce the elastic modulus, but it not only brings about operability problems, but also the comprehensive performance of the plastic encapsulation body deteriorates, making it difficult to meet high performance requirements; from the perspective of the plastic encapsulation process, reducing the plastic encapsulation temperature from 175°C to 125°C can effectively reduce warpage, but it puts forward higher requirements for the plastic encapsulation compound. A Chinese patent application (publication number CN118496625A) discloses a liquid resin composition suitable for compression molding packaging, which mainly increases the amount of silicon powder added by using low-viscosity epoxy resin, and cooperates with castor oil-modified epoxy resin to ensure adhesion and reduce system stress, but it cannot meet the use requirements of compression molding, and needs to be cured for 60 minutes after heating at 150°C, which cannot meet the requirements of low-temperature rapid curing plastic encapsulation process. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a low-temperature and fast-curing powdered epoxy molding compound, which can be injection molded using a compression mold to meet the injection molding needs of thin packages and the low-temperature and fast-curing molding process requirements.

[0004] On one hand, the present invention provides a powdered epoxy molding compound that cures quickly at low temperature. The raw materials for preparing the powdered epoxy molding compound include at least: epoxy resin, curing agent, inorganic filler, and catalyst. The epoxy resin includes at least the epoxy resin described in formula (1) and formula (2). The mass ratio of the epoxy resin described in formula (1) and formula (2) is (3-5): (0.5-1.5).

[0005] Formula (1): Where n = 1 to 3;

[0006] Formula (2):

[0007] As a preferred technical solution, the epoxy resin addition amount in the powdery epoxy molding compound is ≥5wt%.

[0008] Preferably, the epoxy resin added in the powdered epoxy molding compound is 5-7wt%

[0009] As a preferred technical solution, the curing agent at least includes the curing agent described in formula (3),

[0010] Formula (3): Where n=2-5.

[0011] As a preferred technical solution, the weight of the curing agent is not less than 60% of the total weight of the epoxy resin.

[0012] Preferably, the weight of the curing agent is 60-70% of the total weight of the epoxy resin.

[0013] As a preferred technical solution, the catalyst at least includes the catalyst described in formula (4),

[0014] Formula (4):

[0015] Preferably, the amount of catalyst added to the powdered epoxy molding compound is 0.1-0.3 wt %, preferably 0.2-0.3 wt %.

[0016] As a preferred technical solution, the amount of inorganic filler added to the powdery epoxy molding compound is 85-86wt%.

[0017] As a preferred technical solution, the maximum particle size of the inorganic filler is 20 μm.

[0018] As a preferred technical solution, the inorganic filler is selected from at least one of silicon dioxide, silicon powder, and aluminum oxide, preferably silicon dioxide.

[0019] As a preferred technical solution, the raw materials for preparing the powdered epoxy molding compound further include at least one of a silane coupling agent and a release agent;

[0020] As a preferred technical solution, the amount of coupling agent added to the powdered epoxy molding compound is 0.1-0.4wt%.

[0021] As a preferred technical solution, the silane coupling agent at least includes KH-560.

[0022] As a preferred technical solution, the amount of release agent added to the powdered epoxy molding compound is 0.1-0.4wt%.

[0023] As a preferred technical solution, the release agent is selected from at least one of oxidized Fischer-Tropsch wax, micropowder wax, polyethylene wax, low-density oxidized polyethylene wax, and high-density oxidized polyethylene wax, preferably high-density oxidized polyethylene wax.

[0024] Preferably, the acid value of the high-density polyethylene wax is 16-25 mgKOH / g, preferably 16-18 mgKOH / g.

[0025] The present invention optimizes the combination of epoxy resin, curing agent and catalyst in the system so that the provided product meets the requirements of low-temperature rapid curing plastic sealing process. Specifically, the curing agent described in formula (3) is used in combination with the catalyst described in formula (4), which overcomes the problem that the existing epoxy resin system cannot be cured at 125°C or the curing time is too long, and meets the requirements of 125°C low-temperature plastic sealing process. In particular, by introducing an epoxy resin combination with a mass ratio of (3-5): (0.5-1.5) into the control system, the curing time is further reduced, which can effectively reduce warping and maintain high production efficiency.

[0026] Furthermore, the present invention introduces silicon dioxide with a maximum particle size of 20 μm into the system, and controls the addition amount of silicon dioxide with the above particle size in the system to be 85-86 wt %, thereby balancing the thermal expansion coefficient reduction effect and processing performance of the product, so that the spiral flow length of the provided product is ≥60 inches, thereby meeting the demand for thin packaging.

[0027] In addition, the system of the present invention further controls the acid value of the high-density polyethylene wax to be 16-25 mgKOH / g by introducing the silane coupling agent KH-560 and the high-density oxidized polyethylene wax, thereby improving the compatibility of the raw materials in the system, reducing the power consumption during production and processing, and giving the product surface high gloss and smoothness during product molding and demolding in the subsequent compression molding process.

[0028] On the other hand, the present invention provides a method for preparing a powdered epoxy molding compound that cures quickly at low temperature, which comprises at least the following steps: respectively crushing an epoxy resin and a curing agent to obtain an epoxy resin crushed material and a curing agent crushed material; stirring and mixing raw materials other than the epoxy resin and the curing agent, and then adding the epoxy resin crushed material and the curing agent crushed material to stir and mix to obtain a mixture; and extruding, cooling, and crushing the mixture to obtain a powdered epoxy molding compound.

[0029] As a preferred technical solution, the preparation method of the low-temperature fast-curing powdered epoxy molding compound comprises the following steps: respectively crushing the epoxy resin and the curing agent to obtain epoxy resin crushed material and curing agent crushed material, controlling the crushing temperature to be ≤25°C, and the crushing fineness to be less than 3.0 mm, stirring and mixing the raw materials except the epoxy resin and the curing agent, adding the epoxy resin crushed material and the curing agent crushed material to stir and mix to obtain a mixture, and controlling the stirring and mixing temperature to be ≤25°C; using a twin-screw extruder, controlling the extrusion temperature to be 90-120°C, extruding, cooling, crushing, and screening the mixture to obtain a powdered epoxy molding compound with a particle size of less than 3.0 mm.

[0030] Beneficial Effects

[0031] 1. The present invention provides a powdered epoxy molding compound that cures quickly at low temperature and can be injection molded using a compression mold to meet the injection molding needs of thin packages and the requirements of a low-temperature, fast-curing molding process.

[0032] 2. The present invention optimizes the combination of epoxy resin, curing agent and catalyst in the system so that the provided product meets the requirements of low-temperature rapid curing plastic sealing process. Specifically, the curing agent described in formula (3) is used in combination with the catalyst described in formula (4), thereby overcoming the problem that the existing epoxy resin system cannot be cured at 125°C or the curing time is too long, and meeting the requirements of 125°C low-temperature plastic sealing process.

[0033] 3. The present invention further reduces the curing time by introducing an epoxy resin combination with a mass ratio of (3-5): (0.5-1.5) into the control system, which can effectively reduce warping and maintain high production efficiency.

[0034] 4. The present invention introduces silicon dioxide with a maximum particle size of 20 μm into the system, and controls the addition amount of silicon dioxide with the above particle size in the system to be 85-86 wt %, so as to balance the thermal expansion coefficient reduction effect and processing performance of the product, so that the spiral flow length of the provided product is ≥60 inches, thereby meeting the demand for thin packaging.

[0035] 5. The present invention introduces silicon dioxide with a maximum particle size of 20 μm into the system, and controls the addition amount of silicon dioxide with the above particle size in the system to be 85-86 wt%, so as to balance the thermal expansion coefficient reduction effect and processing performance of the product, so that the spiral flow length of the provided product is ≥ 60 inches, meeting the demand for thin packaging. DETAILED DESCRIPTION

[0036] Example 1

[0037] On the one hand, Example 1 of the present invention provides a low-temperature fast-curing powdered epoxy molding compound, and the formula is shown in Table 1 in parts by weight.

[0038] Table 1

[0039]

[0040] On the other hand, Example 1 of the present invention provides a method for preparing a low-temperature, fast-curing powdered epoxy molding compound, comprising the following steps: respectively crushing an epoxy resin and a curing agent to obtain an epoxy resin crushed material and a curing agent crushed material, controlling the crushing temperature to ≤25°C, and the crushing fineness to be less than 3.0 mm, stirring and mixing an inorganic filler, a catalyst, a silane coupling agent, and a release agent, and then adding the epoxy resin crushed material and the curing agent crushed material to stir and mix to obtain a mixture, and controlling the stirring and mixing temperature to ≤25°C; using a twin-screw extruder, controlling the extrusion temperature to 100°C, extruding the mixture, cooling, crushing, and sieving to obtain a powdered epoxy molding compound with a particle size of 0.5-2.0 mm.

[0041] Example 2

[0042] Example 2 of the present invention provides a low-temperature, fast-curing powdered epoxy molding compound and a preparation method thereof. Its specific implementation method is the same as that of Example 1, except that the catalyst formula (4) is replaced by TPP-BQ (triphenylphosphine-1,4-benzoquinone adduct, CAS No.: 5405-63-0).

[0043] Example 3

[0044] Embodiment 3 of the present invention provides a low-temperature fast-curing powdered epoxy molding compound and a preparation method thereof. Its specific implementation method is the same as that of Embodiment 1, except that the amount of epoxy resin formula (1) added is 2 parts by weight, and the amount of epoxy resin formula (2) added is 2 parts by weight.

[0045] Example 4

[0046] Example 4 of the present invention provides a low-temperature fast-curing powdered epoxy molding compound and a preparation method thereof. The specific implementation method is the same as that of Example 1, except that the added amount of the inorganic filler is 87 parts by weight.

[0047] Example 5

[0048] Example 5 of the present invention provides a low-temperature, fast-curing powdered epoxy molding compound and a preparation method thereof. Its specific implementation method is the same as that of Example 1, except that the amount of the inorganic filler added is 88 parts by weight, and a low-temperature, fast-curing powdered epoxy molding compound cannot be produced.

[0049] Performance Testing

[0050] The powdered epoxy molding materials provided in Examples 1-4 were subjected to the performance tests shown in Table 2. The test methods are as follows. The test results are shown in Table 2.

[0051] (1) With reference to GB / T40564-2021, the spiral flow length of the powdered epoxy molding compound of the test example was tested.

[0052] (2) With reference to GB / T40564-2021, the curing time of the powdered epoxy molding compound of the test example at 125°C and 175°C was tested.

[0053] (3) Thermal hardness: GB / T40564-2021, testing the thermal hardness of powdered epoxy molding compound at 175°C.

[0054] (4) With reference to GB / T40564-2021, the glass transition temperature of the powdered epoxy molding compound of the test example was tested.

[0055] (5) At a molding temperature of 175°C, injection pressure: 6.86 MPa (70 kgf / cm 2 ) conditions, the epoxy resin composition was added to an injection molding cylinder and compression molded into a cylinder with a diameter of 5 mm and a height of 5 mm. After post-curing at 175°C for 6 hours, the thermal expansion coefficient 1 (temperature range of 40 to 80 deg-c) and the thermal expansion coefficient 2 (200 to 240 deg-c) were tested using PerkingElmer TMA4000.

[0056] (6) With reference to GB / T40564-2021, the molding shrinkage of the powdered epoxy molding compound of the test example was tested.

[0057] Table 2

[0058] Test items unit Example 1 Example 2 Example 3 Example 4 Spiral flow length inch 65 64 70 48 Curing time (175℃) s 45 42 48 45 Curing time (125℃) s 166 184 188 168 Shore D Hardness - 85 84 83 86 Glass transition temperature ℃ 145 145 138 145 Thermal expansion coefficient 1 ppm 13 13 13 11 Thermal expansion coefficient2 ppm 42 42 43 38 Molding shrinkage ％ 0.22 0.22 0.23 0.15

[0059] Analysis of the above table shows that the product provided in Example 1 achieves rapid curing at a low temperature of 125°C relative to Examples 2 and 3; the product provided in Example 1 has a longer spiral flow length and a shorter curing time at a low temperature of 125°C relative to Example 4.

Claims

1. A low-temperature fast-curing powdered epoxy molding compound, characterized in that: The raw materials for its preparation include at least: epoxy resin, curing agent, inorganic filler, and catalyst. The epoxy resin includes at least the epoxy resin described in formula (1) and formula (2). The mass ratio of the epoxy resin described in formula (1) and formula (2) is (3-5): (0.5-1.5). Formula (1): Where n = 1 to 3; Formula (2):

2. The low-temperature fast-curing powdered epoxy molding compound according to claim 1, characterized in that: The epoxy resin addition amount in the powdery epoxy molding compound is ≥5wt%.

3. The low-temperature fast-curing powdered epoxy molding compound according to claim 1, characterized in that: The weight of the curing agent is not less than 60% of the total weight of the epoxy resin.

4. The low-temperature fast-curing powdered epoxy molding compound according to claim 1, characterized in that: The curing agent at least comprises the curing agent described in formula (3), Formula (3): Where n=2-5.

5. The low-temperature fast-curing powdered epoxy molding compound according to claim 1, characterized in that: The catalyst at least comprises the catalyst described in formula (4), Formula (4):

6. The low-temperature fast-curing powdered epoxy molding compound according to claim 1, characterized in that: The amount of catalyst added to the powdery epoxy molding compound is 0.1-0.3 wt %.

7. The low-temperature fast-curing powdered epoxy molding compound according to claim 1, characterized in that: The amount of inorganic filler added to the powdery epoxy molding compound is 85-86 wt %.

8. The low-temperature fast-curing powdered epoxy molding compound according to claim 7, characterized in that: The maximum particle size of the inorganic filler is 20 μm.

9. The low-temperature fast-curing powdered epoxy molding compound according to claim 1, characterized in that: The raw materials for preparing the powdered epoxy molding compound also include at least one of a silane coupling agent and a release agent.

10. A method for preparing a low-temperature fast-curing powdered epoxy molding compound according to any one of claims 1 to 9, characterized in that: At least the following steps are included: The epoxy resin and the curing agent are crushed separately to obtain epoxy resin crushed material and curing agent crushed material; the raw materials except the epoxy resin and the curing agent are stirred and mixed, and then the epoxy resin crushed material and the curing agent crushed material are added and stirred and mixed to obtain a mixture; the mixture is extruded, cooled and crushed to obtain a powdered epoxy molding compound.

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