High-adherence and low-moisture-absorption solid epoxy molding compound as well as preparation method and application thereof

Abstract

The invention relates to the technical field of semiconductor packaging materials, in particular to a high-adherence and low-moisture-absorption solid epoxy molding compound and a preparation method and application thereof. The high-adherence and low-moisture-absorption solid epoxy molding compound is prepared from the following raw materials in parts by weight: 4 to 10 parts of epoxy resin, 2 to 10 parts of phenolic resin, 70 to 90 parts of inorganic filler, 0.1 to 0.3 part of coloring agent, 0.2 to 0.6 part of release agent, 0.05 to 0.5 part of modified curing accelerator, 0.2 to 1.5 parts of ion trapping agent, 0.1 to 0.3 part of coupling agent, 1 to 5 parts of adherence agent and 0.2 to 1.5 parts of stress improver. Compared with the traditional epoxy molding compound, the high-adherence and low-moisture-absorption solid epoxy molding compound disclosed by the invention has the advantages that under the same curing degree, the obtained epoxy molding compound shows relatively excellent mechanical strength and adherence and extremely low water absorption.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor packaging materials, and in particular to a high-adhesion, low-hygroscopic solid epoxy molding compound and a preparation method and application thereof. Background Art

[0002] As an insulating or structural material, epoxy resin is one of the most widely used integrated circuit packaging materials. Its basic composition includes epoxy resin, phenolic curing agent, curing accelerator, fused silica, coupling agent and release agent. In recent years, about 90% of all semiconductor packaging materials are encapsulated with low-pressure transfer molding compounds made of phenolic resin cured epoxy resin. This epoxy molding compound usually contains a curing accelerator to accelerate the curing reaction of the resin and increase the molding cycle for mass production. However, the reliability of packaged semiconductors varies greatly depending on the type of curing accelerator used. It is important to select an appropriate curing accelerator to improve the reliability of packaged semiconductors, especially in recent years with the emergence of high-end packages such as BGA, POP, Fan-out, MUF, etc., the selection of curing accelerators has become increasingly important. However, conventional accelerators often have problems such as poor high-temperature adhesion, high hygroscopicity, and low reliability in accelerating the curing process of products. This affects its stability, life, packaging effect and product reliability in complex environments. Therefore, developing an epoxy molding compound with excellent adhesion and low moisture absorption at high temperatures is of great significance for improving the quality and reliability of semiconductor packaging.

[0003] Patent document CN108192285A improves the adhesion of EMC to metal substrate by adding tackifiers. However, it requires adding five tackifiers at the same time, the raw materials are complex, the adaptability is poor, and it is easily affected by changes in the supply and demand of raw materials, which is not conducive to stable production.

[0004] Patent document CN114437511A increases the batching process by adding two accelerators, and only improves the mold opening strength and glass transition temperature; Patent document CN107428914B discloses an epoxy resin composition, which uses the reaction product of a carbodiimide compound and an imidazole compound as a potential curing accelerator. Although the storage stability and operability are improved without reducing the properties of the resin cured product, the preparation steps of the curing accelerator are still relatively cumbersome, which is not conducive to promotion and application in mass production.

[0005] In view of the many problems and shortcomings exposed by the existing technology, there is an urgent need for a solid epoxy molding compound with high stability, high adhesion and low moisture absorption to cope with more complex and severe use environments. Summary of the invention

[0006] In view of this, the purpose of the present invention is to provide a solid epoxy molding compound with high adhesion and low moisture absorption, and a preparation method and application thereof, so as to solve the problems of poor stability, insufficient adhesion and strong moisture absorption of traditional solid epoxy molding compounds.

[0007] Based on the above purpose, the present invention provides a high-adhesion, low-hygroscopic solid epoxy molding compound, comprising the following raw materials in parts by weight: 4-10 parts of epoxy resin, 2-10 parts of phenolic resin, 70-90 parts of inorganic filler, 0.1-0.3 parts of colorant, 0.2-0.6 parts of release agent, 0.05-0.5 parts of modified curing accelerator, 0.2-1.5 parts of ion capture agent, 0.1-0.3 parts of coupling agent, 1-5 parts of adhesion agent, and 0.2-1.5 parts of stress improvement agent;

[0008] The preparation steps of the modified curing accelerator are as follows:

[0009] 4-Hydroxymethyl-5-methyl-2-phenylimidazole, triethylamine and tetrahydrofuran are added to a three-necked round-bottom glass flask respectively, and then 3-(3,5-dichlorophenyl)phenol is dissolved in tetrahydrofuran, and added dropwise to the three-necked round-bottom glass flask at 60-70° C., and stirred continuously for 8-9 hours. After the reaction is completed, rotary evaporation, washing and drying are performed to obtain a modified curing accelerator;

[0010] The usage ratio of the 4-hydroxymethyl-5-methyl-2-phenylimidazole, triethylamine, tetrahydrofuran and 3-(3,5-dichlorophenyl)phenol is 5.5-6g:6-7g:180-200ml:3.4-3.7g.

[0011] Preferably, the epoxy resin is one of o-cresol epoxy resin, dicyclopentadiene epoxy resin, polyaromatic epoxy resin, multifunctional epoxy resin, biphenyl epoxy resin, naphthol phenolic epoxy resin, thioether epoxy resin, or a mixture of several of them in any proportion.

[0012] Preferably, the phenolic resin is one of phenolic ether phenolic resin, o-methyl phenolic resin, biphenyl phenolic resin, polyaromatic phenolic resin, phenol aralkyl phenolic resin, or a mixture of several of them in any proportion.

[0013] Preferably, the inorganic filler is one of crystalline silica, fused silica, spherical silica, alumina, talc, kaolin, carbon fiber, glass fiber, or a mixture of several of them in any proportion.

[0014] Preferably, the colorant is one of carbon black, titanium dioxide and aniline black.

[0015] Preferably, the release agent is a wax compound.

[0016] Furthermore, the release agent is one of palm wax, montanate wax, polyethylene wax, oxidized polyethylene wax, and polyamide wax.

[0017] Preferably, the ion capture agent is an anion capture agent.

[0018] Preferably, the coupling agent is one or more of a mercapto-type siloxane coupling agent, an amino-type siloxane coupling agent or an epoxy-type siloxane coupling agent.

[0019] Preferably, the adhesive is one or more of methyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane.

[0020] Preferably, the stress improving agent is any one of silicone oil, silicone rubber and liquid rubber.

[0021] Furthermore, the present invention also provides a method for preparing a high-adhesion, low-hygroscopic solid epoxy molding compound, the specific steps of which are as follows:

[0022] (1) adding the raw materials into a high-speed mixer and stirring them uniformly to obtain a premix;

[0023] (2) The premix is ​​transferred to an extruder, kneaded and mixed thoroughly, cooled and crushed to obtain a high-adhesion, low-hygroscopic solid epoxy molding compound.

[0024] Preferably, the stirring speed of the high-speed stirrer in step (1) is 300-400 rpm, and the stirring time is 10-15 min.

[0025] Preferably, the melting zone temperature of the extruder in step (2) is 100-130°C, and the extrusion temperature is 85-100°C.

[0026] Furthermore, the present invention also provides an application of a high-adhesion, low-hygroscopic solid epoxy molding compound, which is applied to the field of chip packaging, semiconductor packaging, electronic devices, and electromechanical product packaging and protection.

[0027] Beneficial effects of the present invention: The modified curing accelerator of the present invention can react with epoxy groups, reduce the reaction activity of epoxy groups, and optimize its compatibility with epoxy resins; at the same time, due to the introduction of phenyl groups, it is inert at room temperature and has no catalytic effect. It can release active ingredients under high temperature conditions to initiate epoxy resin curing reactions to ensure good stability during storage and processing.

[0028] The modified curing accelerator provided by the present invention has a large number of nitrogen-containing heterocycles and hydroxymethyl groups in its structure during the curing process. Such polarity can form a strong interaction with the metal surface, such as hydrogen bonding or van der Waals force, thereby improving the bonding strength between the epoxy resin and the metal and increasing the adhesion of the encapsulating epoxy molding compound to the Cu / Ag substrate. At the same time, the curing accelerator can introduce alkoxy ions that can further initiate a polymerization reaction, construct a three-dimensional network structure, increase the bonding points between the epoxy resin and the metal interface, and further increase the adhesion.

[0029] The modified curing accelerator provided by the present invention, as an imidazole curing accelerator, forms a more compact three-dimensional network structure during the curing process, reduces the porosity and free volume inside the material, and at the same time, the phenyl group contained in its own structure promotes a higher cross-linking density. As the cross-linking density increases, the movement of the polymer chain is restricted, which limits the penetration and diffusion of water molecules, reduces the adsorption of water, and reduces the water absorption rate. In addition, a higher cross-linking density also provides higher strength. DETAILED DESCRIPTION

[0030] 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.

[0031] The sources or properties of the raw materials used in the embodiments and comparative examples are as follows:

[0032] Epoxy resin: naphthalene epoxy resin (DIC, HP5000); XYLOK phenolic resin (Meiwa Chemicals, Ltd., MEHC-7800M); curing accelerator: 2MZ purchased from Jiangsu Kangle New Materials, 2P4MHZ, 2MZ-A purchased from Shikoku Chemicals, Ltd., phosphorus accelerators TPP-BQ, TPTP purchased from Shanghai Huichuang Trading Co., Ltd.; carbon black MA-600 purchased from Mitsubishi Chemical Corporation; palm wax (Toa Chemicals, Ltd., WAX POWDER); oxidized polyethylene wax (Clariant, Germany, LicowaxE PED); anion scavenger: (Kyowa Chemical, Japan, DHT-4C).

[0033] Example 1: (1) 11 g of 4-hydroxymethyl-5-methyl-2-phenylimidazole, 6 g of triethylamine and 80 ml of tetrahydrofuran were added to a three-necked round-bottom glass flask, and then 2.9 g of 3,3',5,5'-tetrachlorobiphenyl was dissolved in 100 ml of tetrahydrofuran, and added dropwise to the three-necked round-bottom glass flask at 60° C., and stirred for 8 h. After the reaction was completed, the mixture was rotary evaporated, rinsed with deionized water, and then rinsed with acetone. The operation was repeated 2-3 times, and then dried in a vacuum oven at 50° C. for 24 h to obtain a modified curing accelerator;

[0034] (2) 4 g of naphthalene epoxy resin, 2 g of XYLOK phenolic resin, 70 g of 50-70 μm spherical silica, 0.1 g of carbon black, 0.1 g of palm wax, 0.1 g of oxidized polyethylene wax, 0.2 g of anion scavenger, 0.1 g of 3-aminopropyltriethoxysilane, 0.5 g of methyltrimethoxysilane, 0.5 g of 3-mercaptopropyltrimethoxysilane, 0.2 g of silicone oil, and 0.5 g of modified curing accelerator were sequentially added into a high-speed stirrer and stirred at 300 rpm for 10 min to obtain a premix;

[0035] (3) The premix is ​​transferred to an extruder, kneaded and mixed thoroughly, cooled and crushed to obtain a high-adhesion, low-hygroscopic solid epoxy molding compound; wherein the melting section temperature of the extruder is 100° C. and the extrusion temperature is 85° C.

[0036] Example 2: (1) 11.5 g of 4-hydroxymethyl-5-methyl-2-phenylimidazole, 6.5 g of triethylamine and 90 ml of tetrahydrofuran were added to a three-necked round-bottom glass flask, and then 2.95 g of 3,3',5,5'-tetrachlorobiphenyl was dissolved in 100 ml of tetrahydrofuran, and added dropwise to the three-necked round-bottom glass flask at 65° C., and stirred for 9 h. After the reaction was completed, the mixture was rotary evaporated, rinsed with deionized water, and then rinsed with acetone. The operation was repeated 2-3 times, and then dried in a vacuum oven at 50° C. for 27 h to obtain a modified curing accelerator;

[0037] (2) 7 g of naphthalene epoxy resin, 6 g of XYLOK phenolic resin, 80 g of 60 μm spherical silica, 0.2 g of carbon black, 0.3 g of palm wax, 0.1 g of oxidized polyethylene wax, 1 g of anion scavenger, 0.2 g of 3-aminopropyltriethoxysilane, 2 g of methyltrimethoxysilane, 1 g of 3-mercaptopropyltrimethoxysilane, 1 g of silicone oil, and 0.5 g of modified curing accelerator were sequentially added into a high-speed stirrer and stirred at 350 rpm for 13 min to obtain a premix;

[0038] (3) The premix is ​​transferred to an extruder, kneaded and mixed thoroughly, cooled and crushed to obtain a high-adhesion, low-hygroscopic solid epoxy molding compound; wherein the melting section temperature of the extruder is 120° C. and the extrusion temperature is 90° C.

[0039] Example 3: (1) 12 g of 4-hydroxymethyl-5-methyl-2-phenylimidazole, 7 g of triethylamine and 100 ml of tetrahydrofuran were added to a three-necked round-bottom glass flask, and then 3 g of 3,3',5,5'-tetrachlorobiphenyl was dissolved in 100 ml of tetrahydrofuran, and added dropwise to the three-necked round-bottom glass flask at 70° C., and stirred for 9 h. After the reaction was completed, the mixture was rotary evaporated, rinsed with deionized water, and then rinsed with acetone. The operation was repeated 2-3 times, and then dried in a vacuum oven at 50° C. for 30 h to obtain a modified curing accelerator;

[0040] (2) 10 g of naphthalene epoxy resin, 10 g of XYLOK phenolic resin, 90 g of 50-70 μm spherical silica, 0.3 g of carbon black, 0.5 g of palm wax, 0.1 g of oxidized polyethylene wax, 1.5 g of anion scavenger, 0.3 g of 3-aminopropyltriethoxysilane, 3 g of methyltrimethoxysilane, 2 g of 3-mercaptopropyltrimethoxysilane, 1.5 g of silicone oil, and 0.5 g of modified curing accelerator were sequentially added into a high-speed stirrer and stirred at 400 rpm for 15 min to obtain a premix;

[0041] (3) The premix is ​​transferred to an extruder, kneaded and mixed thoroughly, cooled and crushed to obtain a high-adhesion, low-hygroscopic solid epoxy molding compound; wherein the melting section temperature of the extruder is 130° C. and the extrusion temperature is 100° C.

[0042] Comparative Example 1: The difference from Example 2 is that 3,3',5,5'-tetrachlorobiphenyl is replaced by an equal amount of 3,4',5-trichlorobiphenyl. The specific steps are as follows:

[0043] (1) 11.5 g of 4-hydroxymethyl-5-methyl-2-phenylimidazole, 6.5 g of triethylamine and 90 ml of tetrahydrofuran were added to a three-necked round-bottom glass flask respectively, and then 2.95 g of 3,4',5-trichlorobiphenyl was dissolved in 100 ml of tetrahydrofuran, and added dropwise to the three-necked round-bottom glass flask at 65° C., and stirred for 9 hours. After the reaction was completed, the mixture was rotary evaporated, rinsed with deionized water, and then rinsed with acetone. The operation was repeated 2-3 times, and then dried in a vacuum oven at 50° C. for 27 hours to obtain a modified curing accelerator;

[0044] (2) 7 g of naphthalene epoxy resin, 6 g of XYLOK phenolic resin, 80 g of 60 μm spherical silica, 0.2 g of carbon black, 0.3 g of palm wax, 0.1 g of oxidized polyethylene wax, 1 g of anion scavenger, 0.2 g of 3-aminopropyltriethoxysilane, 2 g of methyltrimethoxysilane, 1 g of 3-mercaptopropyltrimethoxysilane, 1 g of silicone oil, and 0.5 g of modified curing accelerator were sequentially added into a high-speed stirrer and stirred at 350 rpm for 13 min to obtain a premix;

[0045] (3) The premix is ​​transferred to an extruder, kneaded and mixed thoroughly, cooled and crushed to obtain a high-adhesion, low-hygroscopic solid epoxy molding compound; wherein the melting section temperature of the extruder is 120° C. and the extrusion temperature is 90° C.

[0046] Comparative Example 2: The difference from Example 2 is that 3,3',5,5'-tetrachlorobiphenyl is replaced by 3,5-dichlorobiphenyl. The specific steps are as follows:

[0047] (1) 11.5 g of 4-hydroxymethyl-5-methyl-2-phenylimidazole, 6.5 g of triethylamine and 90 ml of tetrahydrofuran were added to a three-necked round-bottom glass flask respectively, and then 2.95 g of 3,5-dichlorobiphenyl was dissolved in 100 ml of tetrahydrofuran, and added dropwise to the three-necked round-bottom glass flask at 65° C., and stirred for 9 hours. After the reaction was completed, the mixture was rotary evaporated, rinsed with deionized water, and then rinsed with acetone. The operation was repeated 2-3 times, and then dried in a vacuum oven at 50° C. for 27 hours to obtain a modified curing accelerator;

[0048] (2) 7 g of naphthalene epoxy resin, 6 g of XYLOK phenolic resin, 80 g of 60 μm spherical silica, 0.2 g of carbon black, 0.3 g of palm wax, 0.1 g of oxidized polyethylene wax, 1 g of anion scavenger, 0.2 g of 3-aminopropyltriethoxysilane, 2 g of methyltrimethoxysilane, 1 g of 3-mercaptopropyltrimethoxysilane, 1 g of silicone oil, and 0.5 g of modified curing accelerator were sequentially added into a high-speed stirrer and stirred at 350 rpm for 13 min to obtain a premix;

[0049] (3) The premix is ​​transferred to an extruder, kneaded and mixed thoroughly, cooled and crushed to obtain a high-adhesion, low-hygroscopic solid epoxy molding compound; wherein the melting section temperature of the extruder is 120° C. and the extrusion temperature is 90° C.

[0050] Comparative Example 3: The difference from Example 2 is that 3,3',5,5'-tetrachlorobiphenyl is replaced by 3-chlorobiphenyl. The specific steps are as follows:

[0051] (1) 11.5 g of 4-hydroxymethyl-5-methyl-2-phenylimidazole, 6.5 g of triethylamine and 90 ml of tetrahydrofuran were added to a three-necked round-bottom glass flask respectively, and then 2.95 g of 3-chlorobiphenyl was dissolved in 100 ml of tetrahydrofuran, and added dropwise to the three-necked round-bottom glass flask at 65° C., and stirred for 9 hours. After the reaction was completed, the mixture was rotary evaporated, rinsed with deionized water, and then rinsed with acetone. The operation was repeated 2-3 times, and then dried in a vacuum oven at 50° C. for 27 hours to obtain a modified curing accelerator;

[0052] (2) 7 g of naphthalene epoxy resin, 6 g of XYLOK phenolic resin, 80 g of 60 μm spherical silica, 0.2 g of carbon black, 0.3 g of palm wax, 0.1 g of oxidized polyethylene wax, 1 g of anion scavenger, 0.2 g of 3-aminopropyltriethoxysilane, 2 g of methyltrimethoxysilane, 1 g of 3-mercaptopropyltrimethoxysilane, 1 g of silicone oil, and 0.5 g of modified curing accelerator were sequentially added into a high-speed stirrer and stirred at 350 rpm for 13 min to obtain a premix;

[0053] (3) The premix is ​​transferred to an extruder, kneaded and mixed thoroughly, cooled and crushed to obtain a high-adhesion, low-hygroscopic solid epoxy molding compound; wherein the melting section temperature of the extruder is 120° C. and the extrusion temperature is 90° C.

[0054] Comparative Example 4: The difference from Example 2 is that the curing accelerator is 4-hydroxymethyl-5-methyl-2-phenylimidazole, and the specific steps are as follows:

[0055] (1) 7 g of naphthalene epoxy resin, 6 g of XYLOK phenolic resin, 80 g of 60 μm spherical silica, 0.2 g of carbon black, 0.3 g of palm wax, 0.1 g of oxidized polyethylene wax, 1 g of anion scavenger, 0.2 g of 3-aminopropyltriethoxysilane, 2 g of methyltrimethoxysilane, 1 g of 3-mercaptopropyltrimethoxysilane, 1 g of silicone oil, and 0.5 g of 4-hydroxymethyl-5-methyl-2-phenylimidazole were sequentially added into a high-speed stirrer and stirred at 350 rpm for 13 min to obtain a premix;

[0056] (2) The premix is ​​transferred to an extruder, fully kneaded and mixed, cooled and crushed to obtain a high-adhesion, low-hygroscopic solid epoxy molding compound; wherein the melting section temperature of the extruder is 120° C. and the extrusion temperature is 90° C.

[0057] Comparative Example 5: The difference from Example 2 is that the curing accelerator is 0.1g 2MZ, and the specific steps are as follows:

[0058] (1) 7 g of naphthalene epoxy resin, 6 g of XYLOK phenolic resin, 80 g of 60 μm spherical silica, 0.2 g of carbon black, 0.3 g of palm wax, 0.1 g of oxidized polyethylene wax, 1 g of anion scavenger, 0.2 g of 3-aminopropyltriethoxysilane, 2 g of methyltrimethoxysilane, 1 g of 3-mercaptopropyltrimethoxysilane, 1 g of silicone oil, and 0.1 g of 2MZ were sequentially added into a high-speed stirrer and stirred at 350 rpm for 13 min to obtain a premix;

[0059] (2) The premix is ​​transferred to an extruder, fully kneaded and mixed, cooled and crushed to obtain a high-adhesion, low-hygroscopic solid epoxy molding compound; wherein the melting section temperature of the extruder is 120° C. and the extrusion temperature is 90° C.

[0060] Comparative Example 6: The difference from Example 2 is that the curing accelerator is 0.1g 2MZ-A, and the specific steps are as follows:

[0061] (1) 7 g of naphthalene epoxy resin, 6 g of XYLOK phenolic resin, 80 g of 60 μm spherical silica, 0.2 g of carbon black, 0.3 g of palm wax, 0.1 g of oxidized polyethylene wax, 1 g of anion scavenger, 0.2 g of 3-aminopropyltriethoxysilane, 2 g of methyltrimethoxysilane, 1 g of 3-mercaptopropyltrimethoxysilane, 1 g of silicone oil, and 0.1 g of 2MZ-A were sequentially added into a high-speed stirrer and stirred at 350 rpm for 13 min to obtain a premix;

[0062] (2) The premix is ​​transferred to an extruder, fully kneaded and mixed, cooled and crushed to obtain a high-adhesion, low-hygroscopic solid epoxy molding compound; wherein the melting section temperature of the extruder is 120° C. and the extrusion temperature is 90° C.

[0063] Comparative Example 7: The difference from Example 2 is that the curing accelerator is 0.1 g TPP-BQ, and the specific steps are as follows:

[0064] (1) 7 g of naphthalene epoxy resin, 6 g of XYLOK phenolic resin, 80 g of 60 μm spherical silica, 0.2 g of carbon black, 0.3 g of palm wax, 0.1 g of oxidized polyethylene wax, 1 g of anion scavenger, 0.2 g of 3-aminopropyltriethoxysilane, 2 g of methyltrimethoxysilane, 1 g of 3-mercaptopropyltrimethoxysilane, 1 g of silicone oil, and 0.1 g of TPP-BQ were sequentially added into a high-speed mixer and stirred at 350 rpm for 13 min to obtain a premix;

[0065] (2) The premix is ​​transferred to an extruder, fully kneaded and mixed, cooled and crushed to obtain a high-adhesion, low-hygroscopic solid epoxy molding compound; wherein the melting section temperature of the extruder is 120° C. and the extrusion temperature is 90° C.

[0066] Comparative Example 8: The difference from Example 2 is that the curing accelerator is 0.1 g TPTP, and the specific steps are as follows:

[0067] (1) 7 g of naphthalene epoxy resin, 6 g of XYLOK phenolic resin, 80 g of 60 μm spherical silica, 0.2 g of carbon black, 0.3 g of palm wax, 0.1 g of oxidized polyethylene wax, 1 g of anion scavenger, 0.2 g of 3-aminopropyltriethoxysilane, 2 g of methyltrimethoxysilane, 1 g of 3-mercaptopropyltrimethoxysilane, 1 g of silicone oil, and 0.1 g of TPTP were sequentially added into a high-speed mixer and stirred at 350 rpm for 13 min to obtain a premix;

[0068] (2) The premix is ​​transferred to an extruder, fully kneaded and mixed, cooled and crushed to obtain a high-adhesion, low-hygroscopic solid epoxy molding compound; wherein the melting section temperature of the extruder is 120° C. and the extrusion temperature is 90° C.

[0069] Performance Testing

[0070] According to the standard GB / T40564-2021 "Determination method for epoxy molding compounds for electronic packaging", the spiral flow length, gelation time and strength modulus of the epoxy resin composition prepared in the embodiment and the comparative example were determined, and the test results are shown in the following table.

[0071] Water absorption rate: According to GB / T 40564-2021, the high pressure cooking test (PCT) was used to test the epoxy molding compounds prepared in the embodiments and comparative examples. The temperature was 121°C, the humidity was 100%, and the test was carried out for 120 hours under two standard atmospheric pressures. The sample size requirements were diameter: 50±1mm, thickness: 3±0.2mm. The mass of the sample before and after the test was weighed, and the water absorption rate was calculated. The test results are shown in the following table.

[0072] Glass transition temperature: The glass transition temperature of epoxy molding compound was measured using a static thermomechanical analyzer (TMA) in bending mode. The size of the test sample was 4×4×10 mm, with a starting temperature of 25°C, a heating rate of 5°C / min, and an end temperature of 220°C. The test results are shown in the following table.

[0073] Adhesion: Use a molding machine to mold the obtained epoxy molding compound on the surface of different substrates under the conditions of mold temperature of 175±2℃, injection pressure of 7.0±0.2MPa, and curing time of 120s. Use copper substrate and silver-plated substrate respectively;

[0074] Test action: SEMI G69-0996 standard is adopted. At a speed of 10 mm / min, a shear force is applied along the sample surface to test the maximum value before the plastic packaging material and the sample are separated. The number of each test sample is 10. The average value of the 10 test results is taken as the adhesion test result of each embodiment. The test results are shown in the following table.

[0075] Table 1 Performance test results of embodiments and comparative examples 1-4

[0076]

[0077]

[0078] Table 2 Performance test results of Example 2 and existing products

[0079]

[0080] Data analysis shows that the data obtained from the embodiment in Table 1 show that the epoxy molding compound obtained by adding the modified curing accelerator shows relatively excellent mechanical strength, adhesion and extremely low water absorption at the same degree of curing, and because the modified curing accelerator has good latency, it shows longer fluidity, so that the epoxy molding compound of the present invention can show better storage stability when actually used; the data obtained from the embodiment in Table 2 show that the high-adhesion, low-hygroscopic solid epoxy molding compound of the present invention is compared with the traditional epoxy molding compound. At the same degree of curing, the epoxy molding compound for packaging in Example 2 has the most obvious improvement in adhesion to the Cu / Ag substrate, showing good bending strength and low moisture absorption. Due to its good latency, at the same degree of curing, the amount of Example 2 added is much more than the amount of the accelerator added in Comparative Examples 5-8, and it shows good fluidity in the early stage, and the gelation time is basically consistent with the traditional epoxy molding compound.

[0081] From the test results of Example 2 and Comparative Examples 1-4 in Table 1, it can be seen that 4-hydroxymethyl-5-methyl-2-phenylimidazole is modified by different modifiers and then added to the raw materials as a curing accelerator, so that the storage stability, adhesion and waterproof performance of the epoxy molding compound are greatly improved, and as the halogen groups contained in the modified substance increase, the effect becomes more obvious. This is mainly because as the halogen groups contained in the modified substance continue to increase, the high polarity of tetrachlorobiphenyl can significantly enhance the compatibility of the modified imidazole with the epoxy resin and reduce interface defects. The interface bonding can be strengthened by van der Waals force and hydrogen bond; and the highly substituted biphenyl structure can form a dense cross-linked network during the curing process of the epoxy resin, reducing the porosity and free volume inside the material and thus reducing the water penetration channel. In addition, a higher cross-linking density also provides higher strength. At the same time, the polyphenyl contained in the modified molecule itself is very easy to further promote a higher cross-linking density. As the cross-linking density increases, the movement of the polymer chain is restricted, which limits the penetration and diffusion of water molecules, reduces water adsorption, reduces water absorption, and at the same time, imparts higher strength.

[0082] 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 high-adhesion, low-hygroscopic solid epoxy molding compound, characterized in that: The invention comprises the following raw materials in parts by weight: 4-10 parts of epoxy resin, 2-10 parts of phenolic resin, 70-90 parts of inorganic filler, 0.1-0.3 parts of colorant, 0.2-0.6 parts of release agent, 0.05-0.5 parts of modified curing accelerator, 0.2-1.5 parts of ion capture agent, 0.1-0.3 parts of coupling agent, 1-5 parts of adhesion agent and 0.2-1.5 parts of stress improver; The preparation steps of the modified curing accelerator are as follows: 4-Hydroxymethyl-5-methyl-2-phenylimidazole, triethylamine and tetrahydrofuran are added to a three-necked round-bottom glass flask respectively, and then 3,3',5,5'-tetrachlorobiphenyl is dissolved in tetrahydrofuran, and added dropwise to the three-necked round-bottom glass flask at 60-70°C, and stirred continuously for 8-9 hours. After the reaction is completed, rotary evaporation, washing and drying are performed to obtain a modified curing accelerator; The usage ratio of 4-hydroxymethyl-5-methyl-2-phenylimidazole, triethylamine, tetrahydrofuran and 3,3',5,5'-tetrachlorobiphenyl is 11-12g:6-7g:180-200ml:2.9-3g.

2. The high adhesion, low moisture absorption solid epoxy molding compound according to claim 1, characterized in that: The epoxy resin is one of o-cresol epoxy resin, dicyclopentadiene epoxy resin, polyaromatic epoxy resin, multifunctional epoxy resin, biphenyl epoxy resin, naphthol phenolic epoxy resin, thioether epoxy resin, or a mixture of several of them in any proportion; the phenolic resin is one of phenol ether phenolic resin, o-methyl phenolic resin, biphenyl phenolic resin, polyaromatic phenolic resin, phenol aralkyl phenolic resin, or a mixture of several of them in any proportion.

3. The high adhesion, low moisture absorption solid epoxy molding compound according to claim 1, characterized in that: The inorganic filler is one of crystalline silica, fused silica, spherical silica, alumina, talcum powder, kaolin, carbon fiber, glass fiber, or a mixture of several of them in any proportion.

4. The high adhesion, low moisture absorption solid epoxy molding compound according to claim 1, characterized in that: The colorant is one of carbon black, titanium dioxide, and aniline black; the release agent is one of palm wax, montanate wax, polyethylene wax, oxidized polyethylene wax, and polyamide wax.

5. The high adhesion, low moisture absorption solid epoxy molding compound according to claim 1, characterized in that: The ion capture agent is an anion capture agent; the coupling agent is one or more of a mercapto-type siloxane coupling agent, an amino-type siloxane coupling agent or an epoxy-type siloxane coupling agent.

6. The high adhesion, low moisture absorption solid epoxy molding compound according to claim 1, characterized in that: The adhesive is one or more of methyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and methyltriethoxysilane; the stress improver is any one of silicone oil, silicone rubber, and liquid rubber.

7. A method for preparing a high-adhesion, low-hygroscopic solid epoxy molding compound according to any one of claims 1 to 6, characterized in that: The specific steps are as follows: (1) adding the raw materials into a high-speed mixer and stirring them uniformly to obtain a premix; (2) The premix is ​​transferred to an extruder, kneaded and mixed thoroughly, cooled and crushed to obtain a high-adhesion, low-hygroscopic solid epoxy molding compound.

8. The method for preparing a high-adhesion, low-hygroscopic solid epoxy molding compound according to claim 7, characterized in that: The stirring speed of the high-speed stirrer in step (1) is 300-400 rpm, and the stirring time is 10-15 min.

9. The method for preparing a high-adhesion, low-hygroscopic solid epoxy molding compound according to claim 7, characterized in that: The melting section temperature of the extruder in step (2) is 100-130°C, and the extrusion temperature is 85-100°C.

10. An application of the high-adhesion, low-hygroscopic solid epoxy molding compound according to any one of claims 1 to 6, characterized in that: It is used in chip packaging, semiconductor packaging, electronic devices and electromechanical product packaging and protection fields.

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