Epoxy resin composition with low stress and low hygroscopicity and application thereof

Abstract

The invention relates to the technical field of epoxy molding compounds, in particular to a low-stress low-hygroscopicity epoxy resin composition and application thereof. The low-stress low-hygroscopicity epoxy resin composition is prepared from the following components: epoxy resin, phenolic resin, inorganic filler, a coloring agent, a release agent, a curing accelerator, an ion trapping agent and a coupling agent, the epoxy resin is composed of o-cresol formaldehyde type epoxy resin and branched diphenyl sulfide epoxy resin, and the branched diphenyl sulfide epoxy resin is obtained by crosslinking 4, 4 '-dihydroxy diphenyl sulfide, inositol and epichlorohydrin; by adding the branched diphenyl sulfide epoxy resin into the epoxy resin composition, the mechanical property and the water absorption rate of the epoxy resin composition are remarkably improved, so that the stability and the reliability of a product are improved, and the epoxy resin composition can be used for packaging small and thin integrated circuits.

Description

Technical Field

[0001] The invention relates to the technical field of epoxy molding compounds, and in particular to a low-stress and low-hygroscopic epoxy resin composition and application thereof. Background Art

[0002] Epoxy resin has excellent mechanical properties and good processing and molding processability, and is one of the most widely used resin matrices in composite materials. In recent years, with the development of new technology industries, the demand for composite structural parts has become more and more widespread. Among them, epoxy resin is one of the main raw materials of epoxy resin compositions, and its excellent mechanical properties are particularly important for the various properties of packaging materials.

[0003] Epoxy molding compound has been widely used in the field of electronic packaging, accounting for more than 90% of the packaging market. As an important material for protecting and supporting chips from the external environment, epoxy molding compound has become one of the most common and important packaging materials for modern semiconductor packaging with its low cost, high production efficiency and reasonable reliability. With the increasing miniaturization of electronic equipment, higher integration and more complex structure, when preparing SOP packaging products, due to the large difference in thermal expansion coefficients between chips and packaging materials, the stress increases after packaging, and the packaging is damaged during interface peeling, resulting in moisture absorption and delamination defects, and the reliability of the packaging product fails; while lower water absorption and lower stress can reduce the internal stress of epoxy molding compound during packaging reflow soldering, thereby avoiding delamination inside the product, and preventing the chip surface and leads inside the product from desoldering, affecting the high reliability of SOP packaging products.

[0004] Patent CN117624838A discloses a low heat release, low water absorption, low viscosity epoxy resin composition and its preparation method. The invention uses two epoxy resins to perform prepolymerization to form a prepolymer. The prepared epoxy resin composition has the characteristics of low heat release, resistance to moisture and heat, long storage time and good processability. Although the epoxy composition prepared by this method has low water absorption and low viscosity, the prepolymerization preparation process is complicated, which is not conducive to large-scale industrial production, and is prone to problems such as unstable production batches.

[0005] Patent application CN105778429A uses organic titanium hybrid siloxane to react with hydroxyl groups in epoxy resin to prepare low hygroscopic epoxy resin, but the synthesis process of organic titanium hybrid siloxane is complicated, and the prepared resin system cannot meet the technical requirements of low heat release for thick parts.

[0006] Therefore, the prior art needs to be further developed and improved. In order to adapt to the development of small and thin packaging forms, the epoxy resin composition needs to have lower stress, lower moisture absorption and high reliability, which is a technical problem that those skilled in the art need to solve urgently. Summary of the invention

[0007] In view of this, the purpose of the present invention is to provide a low-stress and low-hygroscopic epoxy resin composition and its application, the prepared epoxy resin composition has the characteristics of low water absorption, high toughness, high bonding strength, high reliability and simple process

[0008] Based on the above purpose, the present invention provides a low-stress and low-hygroscopic epoxy resin composition, which is prepared from the following components by weight: 4-12 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 curing accelerator, 0.2-1.5 parts of ion capture agent and 0.1-0.3 parts of coupling agent;

[0009] Preferably, the epoxy resin is one or a mixture of o-cresol epoxy resin, dicyclopentadiene epoxy resin, polyaromatic epoxy resin, polyfunctional epoxy resin and branched diphenyl sulfide epoxy resin.

[0010] Furthermore, the preparation method of the branched diphenyl sulfide epoxy resin is as follows: under a nitrogen atmosphere, 4,4'-dihydroxydiphenyl sulfide, inositol and epichlorohydrin are mixed, the temperature is raised to 50-60°C, and stirred for 20-40min, and then the pH is adjusted to 8-9 with sodium hydroxide, the temperature is raised to 105-115°C, and stirred for 3-5h, washed with water 3 times, and then the residual inositol and epichlorohydrin are removed by rotary evaporation, and finally vacuum dried at 70-90°C for 10-14h, and ground through a 50-100 mesh sieve to obtain a branched diphenyl sulfide epoxy resin;

[0011] Preferably, the weight ratio of the 4,4'-dihydroxydiphenyl sulfide, inositol and epichlorohydrin is 0.05-0.2:0.1-0.4:1.2-5.

[0012] Preferably, the phenolic resin is one or a mixture of phenol ether phenolic resin, o-methyl phenolic resin, biphenyl phenolic resin, polyaromatic phenolic resin, phenol aralkyl phenolic resin and multifunctional p-phenyl aralkyl phenolic resin.

[0013] Preferably, the inorganic filler is one or a mixture of spherical silica, alumina, talcum powder, kaolin, carbon fiber and glass fiber.

[0014] Preferably, the colorant is carbon black.

[0015] Preferably, the release agent is natural wax or synthetic wax.

[0016] Preferably, the curing accelerator is one or a mixture of several of an imidazole compound, a tertiary amine compound, an organic phosphine compound and an amide compound.

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

[0018] More preferably, the ion capture agent is anion capture agent DHT-4C.

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

[0020] Furthermore, the present invention also provides a method for preparing a low-stress and low-hygroscopic epoxy resin composition, comprising the following steps:

[0021] (1) adding epoxy resin, phenolic resin inorganic filler, colorant, release agent, curing accelerator, ion capture agent and coupling agent into a high-speed mixer in sequence to obtain a premix;

[0022] (2) The premix is ​​transferred to an extruder, kneaded and mixed, cooled and crushed to obtain an epoxy resin composition with low stress and low hygroscopicity.

[0023] Preferably, the melting section temperature of the extruder is 100-130°C, and the extrusion temperature is 85-100°C.

[0024] Furthermore, the present invention also provides an application of a low-stress and low-hygroscopic epoxy resin composition, which can be used for packaging of integrated circuits.

[0025] Beneficial effects of the present invention:

[0026] The present invention significantly improves the mechanical properties and water absorption of the epoxy resin composition by adding a branched diphenyl sulfide epoxy resin to the epoxy resin composition, thereby improving the stability and reliability of the product. Specifically, after adding the branched diphenyl sulfide epoxy resin, the epoxy resin composition shows a significant reduction in bending modulus and water absorption, which makes the encapsulated SOP product not have pore stratification during use, showing good product stability and high reliability. In addition, this modification makes the material have the characteristics of low stress and low hygroscopicity, achieves a higher reliability test, and is suitable for use in harsh environments.

[0027] The inositol in the branched diphenyl sulfide epoxy resin of the present invention can significantly improve the performance of the epoxy resin. The presence of inositol helps to form multiple cross-linking sites, and together with the epoxy resin and the phenolic resin, constructs a highly cross-linked network structure with high toughness. This structure can effectively reduce stress when resisting external forces, while improving the anti-cracking effect of the material during hot and cold cycles; at the same time, compared with bisphenol A epoxy resin, the chain segment of the sulfide bond is long and flexible, which significantly improves the toughness of the resin, so the resin has excellent bending modulus and bending strength; thereby significantly improving the stability of the product. However, although the direct addition of epoxidized inositol can reduce the bending modulus and reduce the water absorption rate, due to its rigid characteristics, it is difficult to effectively reduce the stress of the composition, resulting in easy occurrence of pore stratification when encapsulating SOP products, affecting the reliability of the product. DETAILED DESCRIPTION

[0028] 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.

[0029] Preparation Example 1:

[0030] Under a nitrogen atmosphere, 0.05 g of 4,4'-dihydroxydiphenyl sulfide, 0.1 g of inositol and 1.2 g of epichlorohydrin were mixed, heated to 50°C, stirred for 20 min, and then adjusted to pH 8.1 with sodium hydroxide, heated to 105°C, stirred for 3 h, washed with water 3 times, and then rotary evaporated to remove residual inositol and epichlorohydrin, and finally vacuum dried at 70°C for 10 h, ground through an 80-mesh sieve to obtain a branched diphenyl sulfide epoxy resin.

[0031] Preparation Example 2:

[0032] Under a nitrogen atmosphere, 0.1 g of 4,4'-dihydroxydiphenyl sulfide, 0.2 g of inositol and 2.5 g of epichlorohydrin were mixed, heated to 55°C, stirred for 230 min, and then the pH was adjusted to 8.4 with sodium hydroxide, heated to 1010°C, stirred for 4 h, washed with water 3 times, and then rotary evaporated to remove residual inositol and epichlorohydrin, and finally vacuum dried at 80°C for 12 h, ground through a 80-mesh sieve to obtain a branched diphenyl sulfide epoxy resin.

[0033] Preparation Example 3:

[0034] Under a nitrogen atmosphere, 0.2 g of 4,4'-dihydroxydiphenyl sulfide, 0.4 g of inositol and 5 g of epichlorohydrin were mixed, heated to 60°C, stirred for 40 min, and then adjusted to pH 8.8 with sodium hydroxide, heated to 115°C, stirred for 5 h, washed with water 3 times, and then rotary evaporated to remove residual inositol and epichlorohydrin, and finally vacuum dried at 90°C for 14 h, ground through a 80-mesh sieve to obtain a branched diphenyl sulfide epoxy resin.

[0035] Example 1

[0036] 4 g of o-cresol-formaldehyde epoxy resin CNE195 XL-8, 0.5 g of branched diphenyl sulfide epoxy resin prepared in Preparation Example 1, 2 g of biphenyl phenol-formaldehyde resin MEHC-7851SS, 70 g of spherical silica with a maximum size of 70 μm, 0.1 g of carbon black, 0.2 g of palm wax, 0.05 g of triphenylphosphine-1,4-benzoquinone adduct TPP-BQ, 0.2 g of anion scavenger DHT-4C, and 0.1 g of methyltrimethoxysilane were sequentially added into a high-speed mixer to obtain a premix;

[0037] The premix is ​​transferred to an extruder for kneading, melting and mixing. The melting section temperature of the extruder is 100-130° C., the extrusion temperature is 85-100° C., and the premix is ​​naturally cooled and crushed to obtain a powder, which is preformed into a cake to obtain a low-stress and low-hygroscopic epoxy resin composition.

[0038] Example 2

[0039] 7 g of o-cresol-formaldehyde epoxy resin CNE195 XL-8, 1.2 g of branched diphenyl sulfide epoxy resin prepared in Preparation Example 2, 6 g of biphenyl phenol-formaldehyde resin MEHC-7851SS, 80 g of spherical silica with a maximum size of 70 μm, 0.2 g of carbon black, 0.35 g of palm wax, 0.2 g of triphenylphosphine-1,4-benzoquinone adduct TPP-BQ, 1 g of anion scavenger DHT-4C, 0.1 g of methyltrimethoxysilane and 0.1 g of 3-mercaptopropyltrimethoxysilane were sequentially added into a high-speed mixer to obtain a premix;

[0040] The premix is ​​transferred to an extruder for kneading, melting and mixing. The melting section temperature of the extruder is 100-130° C., the extrusion temperature is 85-100° C., and the premix is ​​naturally cooled and crushed to obtain a powder, which is preformed into a cake to obtain a low-stress and low-hygroscopic epoxy resin composition.

[0041] Example 3

[0042] 10 g of o-cresol-formaldehyde epoxy resin CNE195 XL-8, 2 g of branched diphenyl sulfide epoxy resin prepared in Preparation Example 3, 10 g of biphenyl phenol-formaldehyde resin MEHC-7851SS, 90 g of spherical silica with a maximum size of 70 μm, 0.3 g of carbon black, 0.6 g of palm wax, 0.5 g of triphenylphosphine-1,4-benzoquinone adduct TPP-BQ, 1.5 g of anion scavenger DHT-4C and 0.3 g of 3-mercaptopropyltrimethoxysilane were sequentially added into a high-speed mixer to obtain a premix;

[0043] The premix is ​​transferred to an extruder for kneading, melting and mixing. The melting section temperature of the extruder is 100-130° C., the extrusion temperature is 85-100° C., and the premix is ​​naturally cooled and crushed to obtain a powder, which is preformed into a cake to obtain a low-stress and low-hygroscopic epoxy resin composition.

[0044] Comparative Example 1

[0045] The difference between Comparative Example 1 and Example 2 is that no inositol is added to the raw materials of the branched diphenyl sulfide epoxy resin;

[0046] The specific preparation steps are as follows:

[0047] In a nitrogen atmosphere, 0.3 g of 4,4'-dihydroxydiphenyl sulfide and 2.5 g of epichlorohydrin were mixed, heated to 55°C, stirred for 230 min, then the pH was adjusted to 8.4 with sodium hydroxide, heated to 1010°C, stirred for 4 h, washed with water 3 times, and then the residual epichlorohydrin was removed by rotary evaporation, and finally vacuum dried at 80°C for 12 h, ground through an 80-mesh sieve, to obtain a branched diphenyl sulfide epoxy resin;

[0048] 7 g of o-cresol-formaldehyde epoxy resin CNE195 XL-8, 1.2 g of branched diphenyl sulfide epoxy resin, 6 g of biphenyl phenol-formaldehyde resin MEHC-7851SS, 80 g of spherical silica with a maximum size of 70 μm, 0.2 g of carbon black, 0.35 g of palm wax, 0.2 g of triphenylphosphine-1,4-benzoquinone adduct TPP-BQ, 1 g of anion scavenger DHT-4C, 0.1 g of methyltrimethoxysilane and 0.1 g of 3-mercaptopropyltrimethoxysilane were sequentially added into a high-speed mixer to obtain a premix;

[0049] The premix is ​​transferred to an extruder for kneading, melting and mixing. The melting section temperature of the extruder is 100-130° C., the extrusion temperature is 85-100° C., and the premix is ​​naturally cooled and crushed to obtain a powder, which is preformed into a cake to obtain a low-stress and low-hygroscopic epoxy resin composition.

[0050] Comparative Example 2:

[0051] The difference between Comparative Example 2 and Example 2 is that the branched diphenyl sulfide epoxy resin is replaced by epoxidized inositol;

[0052] The specific preparation steps are as follows:

[0053] In a nitrogen atmosphere, 0.3 g of inositol and 2.5 g of epichlorohydrin were mixed, heated to 55°C, stirred for 230 min, then the pH was adjusted to 8.4 with sodium hydroxide, heated to 1010°C, stirred for 4 h, washed with water 3 times, and then rotary evaporated to remove residual inositol and epichlorohydrin, and finally vacuum dried at 80°C for 12 h, ground through an 80-mesh sieve to obtain epoxy inositol;

[0054] 7 g of o-cresol-formaldehyde epoxy resin CNE195 XL-8, 1.2 g of epoxidized inositol, 6 g of biphenylphenol-formaldehyde resin MEHC-7851SS, 80 g of spherical silica with a maximum size of 70 μm, 0.2 g of carbon black, 0.35 g of palm wax, 0.2 g of triphenylphosphine-1,4-benzoquinone adduct TPP-BQ, 1 g of anion scavenger DHT-4C, 0.1 g of methyltrimethoxysilane and 0.1 g of 3-mercaptopropyltrimethoxysilane were sequentially added into a high-speed mixer to obtain a premix;

[0055] The premix is ​​transferred to an extruder for kneading, melting and mixing. The melting section temperature of the extruder is 100-130° C., the extrusion temperature is 85-100° C., and the premix is ​​naturally cooled and crushed to obtain a powder, which is preformed into a cake to obtain a low-stress and low-hygroscopic epoxy resin composition.

[0056] Comparative Example 3:

[0057] The difference between Comparative Example 3 and Example 2 is that: no branched diphenyl sulfide epoxy resin is added;

[0058] The specific preparation steps are as follows:

[0059] 8.2 g of o-cresol-formaldehyde epoxy resin CNE195 XL-8, 6 g of biphenylphenol-formaldehyde resin MEHC-7851SS, 80 g of spherical silica with a maximum size of 70 μm, 0.2 g of carbon black, 0.35 g of palm wax, 0.2 g of triphenylphosphine-1,4-benzoquinone adduct TPP-BQ, 1 g of anion scavenger DHT-4C, 0.1 g of methyltrimethoxysilane and 0.1 g of 3-mercaptopropyltrimethoxysilane were sequentially added into a high-speed mixer to obtain a premix;

[0060] The premix is ​​transferred to an extruder for kneading, melting and mixing. The melting section temperature of the extruder is 100-130° C., the extrusion temperature is 85-100° C., and the premix is ​​naturally cooled and crushed to obtain a powder, which is preformed into a cake to obtain a low-stress and low-hygroscopic epoxy resin composition.

[0061] Performance Test:

[0062] Referring to GB / T40564-2021 "Test Method for Epoxy Molding Materials for Electronic Packaging", the spiral flow length, gel time, flash, viscosity, strength modulus, hot hardness, appearance inspection and thermal conductivity of the epoxy resin composition prepared in Example 2 and the comparative example were measured;

[0063] High Pressure Cooking Test (PCT): Refer to the standard GB / T 40564-2021, test for 120 hours at 121°C, 100% humidity, and two standard atmospheres. Weigh the mass of the sample before and after the test and calculate the water absorption. Sample size requirements: diameter: 50±1mm, thickness: 3±0.2mm;

[0064] TMA test (Tg): The glass transition temperature (Tg) of the epoxy molding compound was determined using a static thermomechanical analyzer (TMA) in bending mode. The size of the test sample was 4×4×10 mm. The starting temperature was 25°C, the heating rate was 5°C / min, the end temperature was 220°C, and the scan began. The results are shown in Table 1.

[0065] Table 1 Performance test results

[0066]

[0067]

[0068] Data Analysis:

[0069] From the data of Examples 1-3 and Comparative Example 3 in the above table, it can be seen that the epoxy resin composition without adding branched diphenyl sulfide epoxy resin, its comprehensive performance of fluidity, gelation time, overflow, water absorption and strength modulus does not meet the requirements; the epoxy resin composition with added branched diphenyl sulfide epoxy resin has significantly reduced bending modulus and reduced water absorption, and no pore stratification occurs when encapsulating SOP products, the product has good stability, high reliability, and has the characteristics of low stress and low hygroscopicity.

[0070] From the data of Example 2 and Comparative Example 1 in the above table, it can be seen that the branched diphenyl sulfide epoxy resin without inositol will increase the bending modulus of the epoxy resin composition, and the water absorption rate is high, and pore stratification will occur when encapsulating SOP products. This is mainly because inositol helps the branched diphenyl sulfide epoxy resin to form multiple cross-linking sites, and the sulphur bond chain segment is long and flexible, which significantly improves the toughness of the resin; thereby constructing a high-toughness, high-crosslinked network structure with epoxy resin and phenolic resin. When resisting external forces, the high-toughness, high-crosslinked network structure can effectively reduce the stress of the epoxy resin composition; at the same time, the high-toughness, high-crosslinked network structure can improve the anti-cracking effect during the hot and cold cycle process and improve product stability.

[0071] It can be seen from the data of Example 2 and Comparative Example 2 in the above table that directly adding epoxidized inositol will lead to a large number of pore stratification when encapsulating SOP products. This is mainly because the rigid epoxidized inositol is difficult to effectively reduce the stress of the epoxy resin composition and the product stability is poor.

[0072] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

Claims

1. A low stress and low hygroscopicity epoxy resin composition, characterized in that: The invention is prepared from the following components by weight: 4-12 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 curing accelerator, 0.2-1.5 parts of ion capture agent and 0.1-0.3 parts of coupling agent.

2. The low stress and low hygroscopicity epoxy resin composition according to claim 1, characterized in that: The epoxy resin is one or a mixture of o-cresol epoxy resin, dicyclopentadiene epoxy resin, polyaromatic epoxy resin, polyfunctional epoxy resin and branched diphenyl sulfide epoxy resin. The preparation method of the branched diphenyl sulfide epoxy resin is as follows: in a nitrogen atmosphere, 4,4'-dihydroxydiphenyl sulfide, inositol and epichlorohydrin are mixed, the temperature is raised to 50-60°C, and stirred for 20-40 minutes, and then the pH is adjusted to 8-9 with sodium hydroxide, the temperature is raised to 105-115°C, and stirred for 3-5 hours, washed with water for 3 times, and then the residual inositol and epichlorohydrin are removed by rotary evaporation, and finally vacuum dried at 70-90°C for 10-14 hours, and ground through a 50-100 mesh sieve to obtain a branched diphenyl sulfide epoxy resin; The weight ratio of the 4,4'-dihydroxydiphenyl sulfide, inositol and epichlorohydrin is 0.05-0.2:0.1-0.4:1.2-5.

3. The low stress and low hygroscopicity epoxy resin composition according to claim 1, characterized in that: The phenolic resin is one or a mixture of phenol ether phenolic resin, o-methyl phenolic resin, biphenyl phenolic resin, polyaromatic phenolic resin, phenol aralkyl phenolic resin and multifunctional p-phenyl aralkyl phenolic resin.

4. The low stress and low hygroscopicity epoxy resin composition according to claim 1, characterized in that: The inorganic filler is one or a mixture of spherical silica, alumina, talcum powder, kaolin, carbon fiber and glass fiber.

5. The low stress and low hygroscopicity epoxy resin composition according to claim 1, characterized in that: The colorant is carbon black.

6. The low stress and low hygroscopicity epoxy resin composition according to claim 1, characterized in that: The release agent is natural wax or synthetic wax.

7. The low stress and low hygroscopicity epoxy resin composition according to claim 1, characterized in that: The curing accelerator is one or a mixture of several of an imidazole compound, a tertiary amine compound, an organic phosphine compound and an amide compound.

8. The low stress and low hygroscopicity epoxy resin composition according to claim 1, characterized in that: The ion capture agent is an anion capture agent.

9. The low stress and low hygroscopicity epoxy resin composition according to claim 1, characterized in that: The adhesive is one or more of methyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane.

10. A method for preparing the low-stress and low-hygroscopic epoxy resin composition according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) adding epoxy resin, phenolic resin inorganic filler, colorant, release agent, curing accelerator, ion capture agent and coupling agent into a high-speed mixer in sequence to obtain a premix; (2) transferring the premix to an extruder, kneading and mixing, cooling and crushing, and obtaining an epoxy resin composition with low stress and low hygroscopicity; The melting section temperature of the extruder is 100-130°C, and the extrusion temperature is 85-100°C.

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