Low-temperature fast-curing powder epoxy molding compound and preparation method therefor

Abstract

The present invention relates to the technical field of electronic packaging, and in particular to a low-temperature fast-curing powder epoxy molding compound and a preparation method therefor. Raw materials for preparation of the low-temperature fast-curing powder epoxy molding compound at least comprise epoxy resins, a curing agent, an inorganic filler and a catalyst. The epoxy resins at least include an epoxy resin of formula (1) and an epoxy resin of formula (2), wherein the mass ratio of the epoxy resin of formula (1) to the epoxy resin of formula (2) is (3-5):(0.5-1.5). Injection molding can be performed using a compression mold, meeting injection molding requirements of thin packaging and molding process requirements of low-temperature fast-curing.

Description

A low-temperature, rapid-curing powdered epoxy molding compound and its preparation method Technical Field

[0001] This invention relates to the field of electronic packaging technology, specifically to a low-temperature, rapid-curing powdered epoxy molding compound and its preparation method. Background Technology

[0002] In recent years, WLCSP (Wafer-Level Chip Package) and WLPLP (Wan-Out Panel-Level Package) products, which have emerged in the packaging field, have achieved a plastic package area of ​​600*600mm. 2 Correspondingly, warpage control has become a technical challenge. From the perspective of molding compound formulation, an effective method is to increase the filler content to reduce the coefficient of thermal expansion, while using rubber-based stress modifiers such as silicone resins or silicone oils and low-stress resins to reduce the elastic modulus. However, this not only brings operational problems but also deteriorates the overall performance of the molded body, making it difficult to meet high-performance requirements. From the perspective of molding process, reducing the molding temperature from 175℃ to 125℃ can effectively reduce warpage, but it places higher demands on the molding compound. Chinese patent application (publication number CN118496625A) discloses a liquid resin composition suitable for compression molding encapsulation, which mainly uses low-viscosity epoxy resin to increase the amount of silicone powder added, and combines castor oil-modified epoxy resin to ensure adhesion and reduce system stress. However, it cannot meet the requirements of compression molding and requires heating at 150℃ for 60 minutes for curing, which cannot meet the requirements of low-temperature rapid curing molding processes. Summary of the Invention

[0003] To address the aforementioned issues, this invention provides a low-temperature, rapid-curing powdered epoxy molding compound that can be injection molded using compression molds, meeting the injection molding requirements for thin-film packaging and the low-temperature, rapid-curing molding process requirements.

[0004] This invention provides a low-temperature, rapid-curing powdered epoxy molding compound, the raw materials of which include at least: epoxy resin, curing agent, inorganic filler, and catalyst. The epoxy resin includes at least the epoxy resins described in formulas (1) and (2), and the mass ratio of the epoxy resins described in formulas (1) and (2) is (3-5):(0.5-1.5).

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

[0006] Equation (2):

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

[0008] Preferably, the amount of epoxy resin added to the powdered epoxy molding compound is 5-7 wt%.

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

[0010] Equation (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 includes at least the catalyst described in formula (4).

[0014] Equation (4):

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

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

[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 micro powder, and alumina, preferably silicon dioxide.

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

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

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

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

[0023] As a preferred technical solution, the release agent is selected from at least one of Fischer-Tropsch oxidized wax, micronized 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, and more preferably 16-18 mgKOH / g.

[0025] This invention optimizes the combination of epoxy resin, curing agent, and catalyst in the system to provide a product that meets the requirements of low-temperature rapid curing molding processes. Specifically, it uses the curing agent described in formula (3) in combination with the catalyst described in formula (4), overcoming the problem that existing epoxy resin systems cannot be cured at 125°C or have too long a curing time, thus meeting the requirements of low-temperature molding processes at 125°C. In particular, by controlling the introduction of an epoxy resin combination with a mass ratio of (3-5):(0.5-1.5) into the system, the curing time is further reduced, which can effectively reduce warpage and maintain high production efficiency.

[0026] Furthermore, by introducing silica with a maximum particle size of 20 μm into the system and controlling the amount of silica with the above particle size added to the system to be 85-86 wt%, the present invention balances the effect of reducing the coefficient of thermal expansion and the processing performance of the product, so that the spiral flow length of the provided product is ≥60 inches, which meets the requirements of thin packaging.

[0027] Furthermore, by introducing silane coupling agent KH-560 and high-density oxidized polyethylene wax into the system of this invention, the acid value of high-density polyethylene wax is further controlled to 16-25 mgKOH / g, which improves the compatibility of raw materials in the system, reduces power consumption during production and processing, and imparts high gloss and smoothness to the surface of the product when it is demolded in the subsequent compression molding process.

[0028] Another aspect of the present invention provides a method for preparing a low-temperature rapid curing powdered epoxy molding compound, comprising at least the following steps: pulverizing epoxy resin and curing agent separately to obtain epoxy resin pulverized material and curing agent pulverized material; mixing raw materials other than epoxy resin and curing agent and then adding epoxy resin pulverized material and curing agent pulverized material to obtain a mixture; extruding, cooling and pulverizing the mixture to obtain the powdered epoxy molding compound.

[0029] As a preferred technical solution, the preparation method of the low-temperature rapid curing powdered epoxy molding compound includes the following steps: pulverizing epoxy resin and curing agent separately to obtain epoxy resin pulverized material and curing agent pulverized material, controlling the pulverization temperature to ≤25℃ and the pulverization fineness to be below 3.0mm; mixing raw materials other than epoxy resin and curing agent, then adding the epoxy resin pulverized material and curing agent pulverized material and mixing to obtain a mixture, controlling the mixing temperature to ≤25℃; using a twin-screw extruder, controlling the extrusion temperature to 90-120℃, extruding, cooling, pulverizing, and sieving the mixture to obtain powdered epoxy molding compound with a particle size below 3.0mm. Beneficial effects

[0030] 1. This invention provides a low-temperature, rapid-curing powdered epoxy molding compound that can be injection molded using compression molds, meeting the injection molding requirements for thin-film packaging and the molding process requirements for low-temperature, rapid curing.

[0031] 2. This 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 and rapid curing molding process. Specifically, it uses the curing agent described in formula (3) 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 molding process.

[0032] 3. By introducing an epoxy resin combination with a mass ratio of (3-5):(0.5-1.5) into the control system, the present invention further reduces the curing time, which can effectively reduce warpage and maintain high production efficiency.

[0033] 4. This invention introduces silica with a maximum particle size of 20μm into the system, and controls the amount of silica with the above particle size added to the system to be 85-86wt%, thereby balancing the effect of reducing the coefficient of thermal expansion and the processing performance of the product, so that the spiral flow length of the provided product is ≥60inch, which meets the requirements of thin packaging.

[0034] 5. This invention introduces silica with a maximum particle size of 20 μm into the system, and controls the addition amount of silica with the above particle size in the system to 85-86 wt%, thereby balancing the reduction effect of the product's coefficient of thermal expansion and processing performance, so that the spiral flow length of the provided product is ≥60 inches, meeting the requirements of thin packaging. Detailed Implementation

[0035] Example 1

[0036] Embodiment 1 of the present invention provides a low-temperature rapid curing powdered epoxy molding compound, the formulation of which is shown in Table 1 by weight.

[0037] Table 1

[0038] Example 1 of the present invention provides a method for preparing a low-temperature rapid curing powdered epoxy molding compound, comprising the following steps: pulverizing epoxy resin and curing agent separately to obtain epoxy resin pulverized material and curing agent pulverized material, controlling the pulverization temperature to ≤25℃ and the pulverization fineness to be below 3.0mm; mixing inorganic filler, catalyst, silane coupling agent, and release agent, and then adding the epoxy resin pulverized material and curing agent pulverized material to the mixture and stirring to obtain a mixture, controlling the stirring and mixing temperature to ≤25℃; using a twin-screw extruder, controlling the extrusion temperature to 100℃, extruding, cooling, pulverizing, and sieving the mixture to obtain a powdered epoxy molding compound with a particle size of 0.5-2.0mm.

[0039] Example 2

[0040] Example 2 of the present invention provides a low-temperature rapid curing powdered epoxy molding compound and its preparation method. The specific implementation method is the same as that of Example 1, except that the catalyst formula (4) is replaced with TPP-BQ (triphenylphosphine-1,4-benzoquinone adduct, CAS No.: 5405-63-0).

[0041] Example 3

[0042] Example 3 of the present invention provides a low-temperature rapid curing powdered epoxy molding compound and its preparation method. The specific implementation method is the same as that of Example 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.

[0043] Example 4

[0044] Example 4 of the present invention provides a low-temperature rapid curing powdered epoxy molding compound and its preparation method. The specific implementation method is the same as that of Example 1, except that the amount of inorganic filler added is 87 parts by weight.

[0045] Example 5

[0046] Example 5 of the present invention provides a low-temperature rapid curing powdered epoxy molding compound and its preparation method. The specific implementation method is the same as that of Example 1, except that the amount of inorganic filler added is 88 parts by weight, which makes it impossible to produce a low-temperature rapid curing powdered epoxy molding compound.

[0047] Performance testing

[0048] The performance tests of the powdered epoxy molding compounds provided in Examples 1-4 are shown in Table 2. The test methods are as follows, and the test results are shown in Table 2.

[0049] (1) Referring to GB / T40564-2021, the spiral flow length of the powdered epoxy molding compound in the test example was measured.

[0050] (2) Referring to GB / T40564-2021, the curing time of the powdered epoxy molding compound in the test example at 125°C and 175°C was measured.

[0051] (3) Hot hardness: GB / T40564-2021, test the hot hardness of powdered epoxy molding compound at 175℃.

[0052] (4) Referring to GB / T40564-2021, the glass transition temperature of the powdered epoxy molding compound in the test example was determined.

[0053] (5) At a molding temperature of 175℃, the injection pressure is 6.86MPa (70kgf / cm²). 2 Under the conditions of ), the epoxy resin composition was added into the injection molding cylinder and compressed into a cylinder with a diameter of 5 mm and a height of 5 mm. After curing at 175°C for 6 hours, the coefficient of thermal expansion 1 (temperature range of 40 to 80 degrees Celsius) and the coefficient of thermal expansion 2 (200 to 240 degrees Celsius) were tested using PerkingElmer TMA4000.

[0054] (6) Referring to GB / T40564-2021, the molding shrinkage of the powdered epoxy molding compound in the test example was measured.

[0055] Table 2

[0056] Analysis of the table above shows that, compared with Examples 2 and 3, the product provided in Example 1 achieves rapid curing at a low temperature of 125°C; compared with Example 4, the product provided in Example 1 has a longer spiral flow length and a shorter curing time at a low temperature of 125°C.

Claims

1. A low-temperature, rapid-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 at least includes the epoxy resin described in formulas (1) and (2), and the mass ratio of the epoxy resins described in formulas (1) and (2) is (3-5):(0.5-1.5). Formula (1): Where n = 1 to 3; Equation (2):

2. The low-temperature rapid-curing powdered epoxy molding compound according to claim 1, characterized in that, The amount of epoxy resin added in the powdered epoxy molding compound is ≥5wt%.

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

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

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

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

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

8. The low-temperature rapid-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 rapid-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 silane coupling agent and release agent.

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

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