Epoxy resin composition with low stress and low moisture absorption and use thereof

Abstract

The present application relates to the technical field of epoxy encapsulation material, and particularly relates to a low-stress and low-hygroscopicity epoxy resin composition and application thereof. The low-stress and low-hygroscopicity epoxy resin composition is prepared from the following components: epoxy resin, phenolic resin, inorganic filler, colorant, release agent, curing accelerator, ion capture agent and coupling agent; the epoxy resin is composed of o-cresol formaldehyde type epoxy resin and branched diphenyl sulfide epoxy resin, wherein the branched diphenyl sulfide epoxy resin is obtained by crosslinking 4,4'-dihydroxydiphenyl sulfide, inositol and epichlorohydrin; by adding the branched diphenyl sulfide epoxy resin in the epoxy resin composition, the mechanical properties and water absorption of the epoxy resin composition are significantly improved, thereby improving the stability and reliability of the product, and the epoxy resin composition can be used for packaging of small and thin integrated circuits.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of epoxy encapsulation material, and particularly relates to an epoxy resin composition with low stress and low moisture absorption and application thereof. BACKGROUND

[0002] Epoxy resin has excellent mechanical properties and good processing forming process, and is one of the most widely used resin matrices in composite materials. In recent years, with the development of new technology industry, the demand for composite structural parts is becoming more and more widespread. Among them, as one of the main raw materials of epoxy resin composition, the excellent mechanical properties are particularly important for the performance 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 external environment, epoxy molding compound has become one of the most common and important packaging materials in modern semiconductor packaging due to its low cost, high production efficiency and reasonable reliability. With the development of miniaturization of electronic equipment, higher integration and more complex structure, when preparing SOP packaging products, due to the large difference in the thermal expansion coefficient between the chip and the packaging material, the stress after packaging increases, interface peeling occurs, and packaging damage occurs, resulting in moisture absorption and delamination defects, and the reliability of the packaging product fails. Lower water absorption and lower stress can reduce the internal stress of the epoxy molding compound during reflow soldering, thereby avoiding internal delamination of the product and preventing the chip surface and lead from being detached from the solder, affecting the high reliability of the SOP packaging product.

[0004] Patent CN117624838A discloses a low-heat, low-water absorption, low-viscosity epoxy resin composition and a preparation method thereof. The invention adopts two kinds of epoxy resins for pre-polymerization to form a prepolymer, and the prepared epoxy resin composition has the characteristics of low heat release, moisture resistance, long storage time and good processability. Although the epoxy composition prepared by this method has low water absorption and low viscosity, the pre-polymer preparation process is complex, which is not conducive to large-scale industrial production, and problems such as unstable production batches are prone to occur.

[0005] Patent application CN105778429A uses organic titanium hybrid silsesquioxane to react with the hydroxyl groups in the epoxy resin to prepare a low-moisture epoxy resin. However, the synthesis process of organic titanium hybrid silsesquioxane is complex, and the prepared resin system cannot meet the technical requirements of low heat release for large thickness parts.

[0006] Therefore, the existing technology 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 needs to be solved by those skilled in the art. SUMMARY

[0007] Therefore, the present application aims to provide an epoxy resin composition with low stress and low moisture absorption and its application, and the prepared epoxy resin composition has the characteristics of low water absorption, high toughness, high bonding force, high reliability and simple process

[0008] In order to achieve the above purpose, the present application provides an epoxy resin composition with low stress and low moisture absorption, which is prepared from the following components in parts 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 several of ortho-cresol novolac epoxy resin, dicyclopentadiene epoxy resin, polyaromatic epoxy resin, multifunctional epoxy resin and branched diphenyl sulfide epoxy resin.

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

[0011] Preferably, the weight ratio of 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 several of phenolic ether novolac resin, ortho-methyl phenolic resin, diphenyl 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 several of spherical silica, alumina, talc, 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 imidazole compound, tertiary amine compound, organic phosphine compound and amide compound.

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

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

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

[0020] Further, the present application also provides a preparation method of the low-stress and low-hygroscopicity epoxy resin composition, comprising the following steps:

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

[0022] (2) transferring the premix into an extruder, kneading and mixing, cooling, and crushing to obtain the low-stress and low-hygroscopicity epoxy resin composition.

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

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

[0025] The present application has the following beneficial effects:

[0026] The present application significantly improves the mechanical properties and water absorption of the epoxy resin composition by adding the branched diphenyl sulfide epoxy resin, thereby improving the stability and reliability of the product. Specifically, after adding the branched diphenyl sulfide epoxy resin, the epoxy resin composition exhibits significantly reduced bending modulus and reduced water absorption, which makes the packaged SOP product not appear air hole delamination phenomenon during use, and exhibits good product stability and high reliability. In addition, this modification makes the material have the characteristics of low stress and low hygroscopicity, achieves higher reliability test, and is suitable for use in harsh environments.

[0027] The inositol in the branched diphenyl sulfide epoxy resin of the present application can significantly improve the performance of the epoxy resin. The presence of inositol helps to form multiple cross-linking sites, which together with the epoxy resin and phenolic resin build a high-toughness high-crosslinking network structure. This structure can effectively reduce stress when resisting external force, and at the same time improve the anti-cracking effect of the material during the cold and hot cycle process; at the same time, compared with bisphenol A epoxy resin, the long and flexible sulfur bond significantly improves the toughness of the resin, so the resin has excellent bending modulus and bending strength; thereby more significantly improving the stability of the product. However, although the 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 the appearance of air holes and layering when packaging SOP products, affecting the reliability of the product. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with specific examples.

[0029] Preparation Example 1:

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

[0031] Preparation Example 2:

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

[0033] Preparation Example 3:

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

[0035] Example 1

[0036] A pre-mix was obtained by sequentially adding 4 g of o-cresol novolac epoxy resin CNE195 XL-8, 0.5 g of branched diphenyl sulfide epoxy resin prepared in Preparation Example 1, 2 g of biphenyl novolac resin MEHC-7851SS, 70 g of spherical silica having 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 anionic scavenger DHT-4C, and 0.1 g of methyltrimethoxysilane into a high-speed mixer.

[0037] The pre-mix was transferred to an extruder, and kneading melt-mixed at a melt section temperature of 100-130°C and an extrusion temperature of 85-100°C, and extruded to be naturally cooled, pulverized to obtain a powder, pre-formed into a cake to obtain an epoxy resin composition having low stress and low moisture absorption.

[0038] Example 2

[0039] A pre-mix was obtained by sequentially adding 7 g of o-cresol novolac epoxy resin CNE195 XL-8, 1.2 g of branched diphenyl sulfide epoxy resin prepared in Preparation Example 2, 6 g of biphenyl novolac resin MEHC-7851SS, 80 g of spherical silica having 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 anionic scavenger DHT-4C, 0.1 g of methyltrimethoxysilane, and 0.1 g of 3-mercaptopropyltrimethoxysilane into a high-speed mixer.

[0040] The pre-mix was transferred to an extruder, and kneading melt-mixed at a melt section temperature of 100-130°C and an extrusion temperature of 85-100°C, and extruded to be naturally cooled, pulverized to obtain a powder, pre-formed into a cake to obtain an epoxy resin composition having low stress and low moisture absorption.

[0041] Example 3

[0042] A pre-mix was obtained by sequentially adding 10 g of o-cresol novolac epoxy resin CNE195 XL-8, 2 g of branched diphenyl sulfide epoxy resin prepared in Preparation Example 3, 10 g of biphenyl novolac resin MEHC-7851SS, 90 g of spherical silica having 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 anionic scavenger DHT-4C, and 0.3 g of 3-mercaptopropyltrimethoxysilane into a high-speed mixer.

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

[0044] Comparative Example 1

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

[0046] The specific preparation steps are as follows:

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

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

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

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

[0054] 7 g of o-cresol novolac epoxy resin CNE195 XL-8, 1.2 g of epoxidized inositol, 6 g of biphenyl novolac 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 anionic trapping agent DHT-4C, 0.1 g of methyltrimethoxysilane, and 0.1 g of 3-mercaptopropyltrimethoxysilane were sequentially added to a high-speed mixer to obtain a premix;

[0055] The premix was transferred to an extruder for kneading and melting mixing, the melting section temperature of the extruder was 100-130℃, the extrusion temperature was 85-100℃, and the extrusion was naturally cooled, crushed to obtain a powder, preformed into a cake to obtain an epoxy resin composition with low stress and low moisture absorption.

[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 novolac epoxy resin CNE195 XL-8, 6 g of biphenyl novolac 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 anionic trapping agent DHT-4C, 0.1 g of methyltrimethoxysilane, and 0.1 g of 3-mercaptopropyltrimethoxysilane were sequentially added to a high-speed mixer to obtain a premix;

[0060] The premix was transferred to an extruder for kneading and melting mixing, the melting section temperature of the extruder was 100-130℃, the extrusion temperature was 85-100℃, and the extrusion was naturally cooled, crushed to obtain a powder, preformed into a cake to obtain an epoxy resin composition with low stress and low moisture absorption.

[0061] Performance test:

[0062] According to the standard GB / T40564-2021 "Epoxy plastic packaging material for electronic packaging", the spiral flow length, gelation time, flash, viscosity, strength modulus, thermal hardness, appearance detection and thermal conductivity of the epoxy resin composition prepared in Example 2 and Comparative Example were determined;

[0063] High pressure cooking test (PCT): refer to the standard GB / T 40564-2021, temperature 121℃, humidity 100%, two standard atmospheres for 120 hours, weigh the mass of the sample before and after the test, 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 encapsulation material was determined by static thermal mechanical analyzer (TMA) in bending mode, the size of the test sample was 4×4×10mm, the starting temperature was 25℃, the heating rate was 5℃ / min, the final temperature was 220℃, and the scanning was started. 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 does not meet the requirements in terms of flowability, gelation time, overflow, water absorption and strength modulus comprehensive performance; the epoxy resin composition added with branched diphenyl sulfide epoxy resin has significantly reduced bending modulus and water absorption, and no air hole layering occurs when packaging SOP products, the product has good stability, high reliability, low stress and low moisture absorption characteristics.

[0070] From the data of Example 2 and Comparative Example 1 in the above table, it can be seen that branched diphenyl sulfide epoxy resin without inositol will increase the bending modulus of the epoxy resin composition, and the water absorption is high, and air hole layering will occur when packaging SOP products, which is mainly due to the fact that inositol helps branched diphenyl sulfide epoxy resin to form multiple crosslinking sites, and the long and flexible sulfur bond significantly improves the toughness of the resin; thereby constructing a high-toughness high-crosslinking network structure with epoxy resin and phenolic resin, which can effectively reduce the stress of the epoxy resin composition when resisting external force; at the same time, the high-toughness high-crosslinking network structure can improve the anti-cracking effect in the cold and hot cycle process, and improve the product stability.

[0071] From the data of Example 2 and Comparative Example 2 in the above table, it can be seen that directly adding epoxidized inositol will cause a large amount of air hole layering when packaging SOP products, which is mainly due to the fact that the rigid epoxidized inositol is difficult to effectively reduce the stress of the epoxy resin composition, and the product has poor stability.

[0072] It should be understood by those of ordinary skill in the art that the above discussion of any of the embodiments is merely exemplary in nature and is not intended to imply limitations on the scope of the application: limited to these examples; the technical features between the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other changes of different aspects of the application as described above. In order to be brief, they are not provided in details.

Claims

1. An epoxy resin composition of low stress and low moisture absorption, characterized by, The epoxy resin composition is prepared from the following components by weight parts: epoxy resin 4-12 parts, phenolic resin 2-10 parts, inorganic filler 70-90 parts, colorant 0.1-0.3 parts, release agent 0.2-0.6 parts, curing accelerator 0.05-0.5 parts, ion capture agent 0.2-1.5 parts and coupling agent 0.1-0.3 parts; the epoxy resin is a mixture of o-cresol novolac epoxy resin and branched diphenyl sulfide epoxy resin in a weight ratio of 4-10:0.5-2; The preparation method of the branched diphenyl sulfide epoxy resin is as follows: under nitrogen atmosphere, 4,4'-dihydroxydiphenyl sulfide, inositol and epichlorohydrin are mixed, heated to 50-60℃, stirred for 20-40 min, then the pH is adjusted to 8-9 using sodium hydroxide, heated to 105-115℃, stirred for 3-5 h, washed with water for 3 times, then the residual inositol and epichlorohydrin are removed by rotary evaporation, finally vacuum dried at 70-90℃ for 10-14 h, ground through a 50-100 mesh sieve to obtain the 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.

2. The low stress and low moisture absorption epoxy resin composition according to claim 1, characterized by, The phenolic resin is one or a mixture of several of phenolic ether novolac resin, o-methyl phenolic resin, diphenyl phenolic resin, phenol aralkyl phenolic resin and multifunctional p-benzene aralkyl phenolic resin.

3. The low stress and low moisture absorption epoxy resin composition according to claim 1, characterized by, The inorganic filler is one or a mixture of several of spherical silica, alumina, talc, kaolin, carbon fiber and glass fiber.

4. The low stress and low moisture absorption epoxy resin composition according to claim 1, characterized by, The colorant is carbon black.

5. The low stress and low moisture absorption epoxy resin composition according to claim 1, characterized by, The release agent is natural wax or synthetic wax.

6. The low stress and low moisture absorption epoxy resin composition according to claim 1, characterized by, The curing accelerator is one or a mixture of several of imidazole compound, tertiary amine compound, organic phosphine compound and amide compound.

7. The low stress and low moisture absorption epoxy resin composition according to claim 1, wherein The ion capture agent is an anion capture agent.

8. The low stress and low moisture absorption epoxy resin composition according to claim 1, characterized by, The coupling agent is one or several of methyl trimethoxysilane, 3-mercaptopropyl trimethoxysilane and methyl triethoxysilane.

9. A method for producing the low-stress and low-moisture-absorption epoxy resin composition according to any one of claims 1 to 8, characterized by, The method comprises the following steps: (1) the epoxy resin, phenolic resin, inorganic filler, colorant, release agent, curing accelerator, ion capture agent and coupling agent are sequentially added into a high-speed mixer to obtain a premix; (2) the premix is transferred into an extruder for kneading and mixing, then cooled and crushed to obtain the epoxy resin composition with low stress and low moisture absorption; The melting section temperature of the extruder is 100-130℃ and the extrusion temperature is 85-100℃.

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