A low stress, low shrinkage and high reliability epoxy molding compound

Abstract

The invention relates to a low-stress, low-shrinkage and high-reliability epoxy molding compound, comprising the following components by weight: 3.5-12.3 parts of epoxy resin, 0.6-2 parts of organosilicon-modified epoxy resin, 1-2 parts of polyol diluent, 5-6 parts of phenolic resin curing agent, 0.1-0.2 parts of accelerator, 80-85 parts of powder filler, 0.2-0.3 parts of coupling agent, 0.5-0.6 parts of release agent and 0.3-0.4 parts of carbon black. The invention has the advantages that the scientific compatibility of various components and raw materials is assisted by a reasonable processing method to obtain the epoxy molding compound with low stress, low shrinkage, good temperature resistance and high reliability.

Description

Technical Field

[0001] The invention relates to the field of resin molding compounds, in particular to a low-stress, low-shrinkage and high-reliability epoxy molding compound. Background Art

[0002] Epoxy resin refers to a polymer containing two or more epoxy groups in its molecule. Due to its good insulation, bonding and mechanical properties, it is widely used in the fields of chemistry, industry, civil, national defense science and technology, ships and aircraft. Due to its bonding and mechanical properties, epoxy resin is suitable for the packaging of advanced materials such as copper clad laminates, chips and wafers, and is a commonly used packaging material.

[0003] At present, there is a Chinese patent with publication number CN106674911A, which discloses a high-adhesion epoxy molding compound for semiconductor packaging, wherein the epoxy resin content in the epoxy molding compound is 5-18wt%, the phenolic resin content is 2.5-10wt%, the curing accelerator content is 0.05-0.5wt%, the filler content is 60-90wt%, the adhesion modifier content is 0.1-0.8wt%, the release agent content is 0.1-1.5wt% and the coupling agent content is 0.1-1wt%. The curing accelerator is an imidazole compound, a tertiary amine compound and an organic phosphine compound.

[0004] The epoxy resin group reacts with the curing accelerator to generate the epoxy resin. The molecular structure is centered on the ternary epoxy group. It cures with other functional groups to form a polymer. The spatial arrangement of the molecules changes, resulting in shrinkage. In the curing process, heat is released when the reaction occurs. This heat causes the volume of the epoxy resin to shrink, resulting in greater stress. However, with the deepening of chip integration and the increase in chip wiring density, higher requirements are placed on the stress index and shrinkage ratio of the plastic encapsulation material.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0006] In view of the deficiencies of the prior art, the invention discloses a low-stress, low-shrinkage and high-reliability epoxy molding compound.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A low-stress, low-shrinkage, high-reliability epoxy molding compound, characterized in that it comprises the following components by weight: 3.5-12.3 parts of epoxy resin, 0.6-2 parts of organosilicon-modified epoxy resin, 1-2 parts of polyol diluent, 5-6 parts of phenolic resin curing agent, 0.1-0.2 parts of accelerator, 80-85 parts of powder filler, 0.2-0.3 parts of coupling agent, 0.5-0.6 parts of release agent and 0.3-0.4 parts of carbon black.

[0009] Furthermore, the epoxy resin is a bisphenol A epoxy resin or a novolac epoxy resin, and the epoxy equivalent is 120 to 230 eq.

[0010] Furthermore, the organosilicon-modified epoxy resin is a POSS type organosilicon resin, and the POSS type organosilicon resin includes glycidyloxypropyl caged polysilsesquioxane, glycidyloxypropyl cyclotetrasiloxane and octacyclohexylethyl caged polysilsesquioxane.

[0011] Furthermore, the polyol diluent includes polyether diol, polyester diol, polycaprolactone diol or triol, and the hydroxyl value of the polyol diluent is 100-320 mgKOH / g.

[0012] Furthermore, the hydroxyl equivalent of the phenolic resin curing agent is 80-200 g / eq.

[0013] Furthermore, the accelerator is a latent curing agent, and the latent curing agent includes a tertiary amine latent curing agent and an imidazole latent curing agent.

[0014] Furthermore, the powder filler is silicon dioxide and aluminum hydroxide, and the D50 particle size is 0.5-30 microns.

[0015] Furthermore, the coupling agent is an amino coupling agent.

[0016] Furthermore, the release agent is a solid release agent or a liquid release agent.

[0017] A method for preparing a low-stress, low-shrinkage, high-reliability epoxy molding compound according to claim 1, characterized in that it comprises the following steps:

[0018] Step S1, melt-mixing epoxy resin, organosilicon-modified epoxy resin, phenolic resin curing agent and accelerator at high temperature to obtain epoxy resin prepolymer;

[0019] Step S2, the epoxy resin prepolymer is cooled and then crushed, the crushed epoxy resin prepolymer powder filler, polyol diluent, coupling agent, release agent and carbon black are mixed, and then melt-mixed, and the material is extruded, cooled, crushed and other processes to obtain a sheet product;

[0020] Step S3, the flaky product is crushed and ground into granular powder, which is pressed by a cake maker to obtain a solid rubber cake, and the product is dried and stored at low temperature.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. In the basic epoxy resin system, silicone-modified epoxy resin is introduced. Its essence is polyhedral oligomeric silsesquioxane, which has small shrinkage, small stress release, good temperature resistance and aging resistance. When introduced into phenolic epoxy resin, it can interact with the molecular chain of epoxy resin, form an effective dispersed phase in the epoxy resin, and increase the crosslinking density of the resin and the interaction force between molecules. This enhancement enables the epoxy resin to better resist stress and shrinkage during the curing process, thereby improving its overall performance.

[0023] 2. The selection of phenolic resin curing agent is mainly based on its chemical reactivity and compatibility with epoxy resin. The phenolic hydroxyl group in phenolic resin can react with the epoxy group in epoxy resin to form a three-dimensional network structure, thereby increasing the cross-linking density of the cured product and thus improving the reliability of the final product.

[0024] 3. The hydroxyl equivalent of the phenolic resin curing agent is controlled within the range of 80-200g / eq, which directly affects the speed and degree of the curing reaction. If the hydroxyl equivalent is too low, the curing reaction may be too rapid, resulting in more residual stress and shrinkage in the cured product; while if the hydroxyl equivalent is too high, the curing reaction may be too slow, affecting production efficiency. Therefore, a balance point is chosen to make the curing reaction proceed at an appropriate speed, which not only ensures production efficiency, but also can obtain a cured product with excellent performance.

[0025] 4. The introduction of polyol diluent can adjust the viscosity of phenolic epoxy resin and improve its processing performance. Epoxy resin often has a higher viscosity before curing, and the hydroxyl value is controlled in the range of 100-320mgKOH / g to ensure that the phenolic epoxy resin has appropriate crosslinking density and physical properties. If the hydroxyl value is too low, it may lead to incomplete curing, affecting the mechanical properties and chemical stability of the resin; while if the hydroxyl value is too high, the resin may be too hard, reducing its flexibility and impact resistance.

[0026] 5. For tertiary amine latent curing agents, the principle is mainly to block its activity through steric hindrance effect or chemical reaction, so that the mixed material remains stable at room temperature; imidazole latent curing agents are a class of highly active curing agents, which are usually formed by introducing larger substituents into the imidazole molecule to form imidazole derivatives with steric hindrance, or reacting with inorganic salts of transition metals to form corresponding imidazole salt complexes. Under specific conditions (such as heating), these imidazole latent curing agents can quickly react with epoxy resins to achieve curing.

[0027] 6. As inorganic fillers, silicon dioxide and aluminum hydroxide have high hardness and strength. After mixing with epoxy resin, they can effectively improve the rigidity and wear resistance of the composite material. By controlling the D50 particle size of the filler between 0.5-30 microns, the smaller particle size can make the filler better dispersed in the epoxy resin to form a uniform composite material, thereby improving its overall performance.

[0028] 7. The amino functional group in the amino coupling agent can react chemically with the epoxy group in the epoxy resin or the functional group in the POSS-type silicone to form a stable chemical bond. The formation of this chemical bond can increase the cross-linking points in the resin system, thereby increasing the cross-linking density. A higher cross-linking density means that the connection between the resin molecules is tighter, which can effectively improve the mechanical properties and thermal stability of the material. The amino coupling agent can act as a "bridge" to connect the organic phase and the inorganic phase and enhance the interfacial interaction between the two phases. By introducing the amino coupling agent, the compatibility between fillers (such as silica and aluminum hydroxide) and the epoxy resin matrix can be improved, interface defects can be reduced, and the overall performance of the composite material can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the steps of the method for preparing low-stress, low-shrinkage and high-reliability epoxy molding compound. DETAILED DESCRIPTION

[0030] The specific implementation of the present invention will be described below in conjunction with the accompanying drawings.

[0031] Embodiment 1:

[0032] A low-stress, low-shrinkage, high-reliability epoxy molding compound, comprising the following components by weight:

[0033] 3.5 parts of bisphenol A epoxy resin, the specific model is NPEL-128E; 5.8 parts of phenolic epoxy resin, the specific model is SQPN-631, a total of 9.3 parts of epoxy resin;

[0034] 0.8 parts of the organosilicon-modified epoxy resin is a POSS-type organosilicon resin, specifically glycidyl ether oxypropyl caged polysilsesquioxane;

[0035] 1 part of polyol diluent Terol 2801, with a hydroxyl value of 235-265KOH / g;

[0036] 5 parts of phenolic resin curing agent Shandong Shengquan SH-5110, hydroxyl equivalent of 224-234 / eq;

[0037] 0.2 parts of accelerator, the specific model is tertiary amine latent curing agent MY-25;

[0038] The powder filler includes 12.5 parts of aluminum hydroxide H-WF-01 and 70 parts of silicon dioxide 2500SQ, with a D50 particle size of 0.5-30 microns;

[0039] 0.3 parts of coupling agent amino coupling agent, specific model is KH-550;

[0040] 0.5 parts of release agent Carabar wax;

[0041] 0.4 parts of carbon black.

[0042] The method for preparing the above-mentioned low-stress, low-shrinkage and high-reliability epoxy molding compound comprises the following steps:

[0043] Step S1, melt-mix 3.5 parts of NPEL-128E, 5.8 parts of SQPN-631, 0.8 parts of glycidyloxypropyl cage polysilsesquioxane, 5 parts of SH-5110, and 0.2 parts of MY-25 at 80°C, and react for 12 hours to obtain an epoxy resin prepolymer with a softening point of 85°C.

[0044] Step S2, the epoxy resin prepolymer is cooled and crushed to a particle size of less than 3 mm, and put into a twin-screw kneader together with 12.5 parts of H-WF-01, 70 parts of 2500SQ, 1 part of DP-750, 0.3 parts of KH-550, 0.5 parts of Laba wax and 0.4 parts of carbon black, and melt-mixed at 75°C. The material is subjected to extrusion, cooling, crushing and other processes to obtain a flaky product.

[0045] Step S3: the flaky product is crushed and ground into a granular powder with a particle size of less than 2 mm, and a solid rubber cake of a specific shape and weight is prepared by a cake making machine. The product is dried and stored at low temperature.

[0046] Embodiment 2:

[0047] A low-stress, low-shrinkage, high-reliability epoxy molding compound, comprising the following components by weight:

[0048] 10.12 parts of phenolic epoxy resin, specific model is SQCN700-2;

[0049] 1.6 parts of the organosilicon-modified epoxy resin is a POSS type organosilicon resin, specifically octaepoxycyclohexylethyl caged polysilsesquioxane;

[0050] 1.6 parts of polyol diluent, the specific model is PCL205, and its hydroxyl value is 207-217KOH / g;

[0051] 5.5 parts of phenolic resin curing agent, the specific model is Shandong Shengquan PF-8020, and the hydroxyl equivalent is 105-109 / eq;

[0052] 0.15 parts of accelerator, specific model is 2MZ-A;

[0053] The powder filler includes 65 parts of silicon dioxide DC1010 and 15 parts of aluminum hydroxide H-42M, and the D50 particle size is 0.5-30 microns;

[0054] 0.2 parts of coupling agent amino coupling agent, specific model is KH-550;

[0055] 0.53 parts of release agent calcium stearate;

[0056] 0.3 parts of carbon black.

[0057] The method for preparing the above-mentioned low-stress, low-shrinkage and high-reliability epoxy molding compound comprises the following steps:

[0058] Step S1, melt-mix 10.12 parts of SQCN700-2, 1.6 parts of octaepoxycyclohexylethyl cage polysilsesquioxane, 5.5 parts of PF-8820, and 0.15 parts of 2MZ-A at 95°C, and react for 12 hours to obtain an epoxy resin prepolymer with a softening point of 93°C.

[0059] Step S2, the epoxy resin prepolymer is cooled and crushed to a particle size of less than 3 mm, and put into a twin-screw kneader together with 65 parts of DC1010, 15 parts of H-42M, 1.6 parts of PCL205, 0.2 parts of KH-550, 0.53 parts of calcium stearate and 0.3 parts of carbon black, and melt-mixed at 85°C. The material is extruded, cooled, crushed and other processes to obtain a flaky product.

[0060] Step S3: the flaky product is crushed and ground into a granular powder with a particle size of less than 2 mm, and a solid rubber cake of a specific shape and weight is prepared by a cake making machine. The product is dried and stored at low temperature.

[0061] Embodiment 3:

[0062] A low-stress, low-shrinkage, high-reliability epoxy molding compound, comprising the following components by weight:

[0063] 1.25 parts of phenolic epoxy resin, the specific model is SQDN-302, 1.5 parts of phenolic epoxy resin, the specific model is NPPN-638;

[0064] 2 parts of the organosilicon-modified epoxy resin are POSS type organosilicon resins, specifically glycidyloxypropylcyclotetrasiloxane;

[0065] 2 parts of polyol diluent, the specific model is PCL305, and its hydroxyl value is 300-310KOH / g;

[0066] 5.5 parts of phenolic resin curing agent, the specific model is Shandong Shengquan SH-3120, and the hydroxyl equivalent is 118-122 / eq;

[0067] 0.1 part of accelerator, the specific model is PN-23;

[0068] The powder filler includes 70 parts of silicon dioxide DC1180 and 15 parts of aluminum hydroxide DF1195N, with a D50 particle size of 0.5-30 microns;

[0069] 0.23 parts of coupling agent amino coupling agent, specific model is KH-550;

[0070] 0.6 parts of release agent stearic acid;

[0071] 0.32 parts of carbon black.

[0072] The method for preparing the above-mentioned low-stress, low-shrinkage and high-reliability epoxy molding compound comprises the following steps:

[0073] Step S1, melt-mix 1.25 parts of SQDN-302, 1.5 parts of NPPN-638, 2 parts of glycidyloxypropyl cyclotetrasiloxane, 6 parts of SH-3120, and 0.1 parts of PN-23 at 100°C, and react for 12 hours to obtain an epoxy resin prepolymer with a softening point of 87°C.

[0074] Step S2, the epoxy resin prepolymer is cooled and crushed to a particle size of less than 3 mm, and put into a twin-screw kneader together with 15 parts of DF1195N, 70 parts of DC1180, 2 parts of PCL305, 0.23 parts of KH-550, 0.6 parts of stearic acid and 0.32 parts of carbon black, and melt-mixed at 75°C. The material is subjected to extrusion, cooling, crushing and other processes to obtain a flaky product.

[0075] Step S3: the flaky product is crushed and ground into a granular powder with a particle size of less than 2 mm, and a solid rubber cake of a specific shape and weight is prepared by a cake making machine. The product is dried and stored at low temperature.

[0076] Performance testing of low stress, low shrinkage and high reliability epoxy molding compound:

[0077] Experimental Group:

[0078] In Examples 1 to 3, low-stress, low-shrinkage, and high-reliability epoxy molding compounds are prepared.

[0079] Performance control group:

[0080] The epoxy resin molding materials purchased on the market are Sumitomo G591 and Changxing 3600GT.

[0081] The specific test results are shown in Table 1.

[0082]

[0083]

[0084] Table 1

[0085] Experimental results analysis:

[0086] The three embodiments provided by the present invention have a spiral flow length of about 100 cm, a bending strength of about 150 MPa, a bending modulus of about 20 GPa, a glass transition temperature of 160°C, and a linear expansion coefficient a1 / a2 between 10-15 ppm / K and 30-50 ppm / K, which meet the actual use needs of chip packaging.

[0087] It is worth mentioning that Examples 1-3 have excellent low stress, low shrinkage, and outstanding reliability, which are mainly manifested in three aspects: thermal shock performance, curing shrinkage, and PCT test water absorption. After thermal shock testing, the number of failures of Examples 1-3 is greater than 96 cycles, the curing shrinkage is less than 0.04%, and the water absorption of the product after PCT test is less than 0.22%, indicating that the embodiments given in the present invention have outstanding performance in low stress, low shrinkage, and high reliability, and can solve the technical problems in the existing chip packaging field.

[0088] Among them, Example 1 is a product with good comprehensive performance and moderate cost performance, Example 2 has the characteristics of high Tg and small shrinkage, and Example 3 emphasizes the characteristics of low linear expansion coefficient, small stress and high reliability.

[0089] It is not difficult to see from the comparative data provided in Table 1 that there is no significant difference between the commercially available products and the examples provided by the present invention in terms of spiral flow length, bending strength, bending modulus, glass transition temperature and other indicators, but there are obvious differences in thermal shock test, curing shrinkage and PCT water absorption. Sumitomo G591 cracked after 16 cycles of thermal shock test, while this indicator of Changxing 3600GT was 12 cycles; Sumitomo G591 had a curing shrinkage of 0.15% and a PCT water absorption of 1.52%, while Changxing 3600GT had a curing shrinkage of 0.23% and a PCT water absorption of 1.97%. The plastic encapsulation material prepared by the present invention is obviously superior to the mainstream plastic encapsulation materials on the market in terms of stress, shrinkage and reliability.

[0090] In order to verify the irreplaceability of each component used in the present invention, the following comparative examples were set up and relevant performance tests were performed.

[0091] Comparative Example 1:

[0092] On the basis of Example 1, the special silicone-modified epoxy resin glycidyl ether oxypropyl caged polysilsesquioxane was replaced with phenolic epoxy resin SQPN-631. The remaining components and preparation process were the same.

[0093] Comparative Example 2:

[0094] Based on Example 1, the polyol diluent DP-750 was removed. The remaining components and preparation process were the same.

[0095] Comparative Example 3:

[0096] On the basis of Example 1, the powder filler H-WF-01 was replaced with 2500SQ. The remaining components and preparation process were the same.

[0097] Comparative Example 4:

[0098] On the basis of Example 1, the powder filler H-WF-01 was replaced with 2500SQ. The remaining components and preparation process were the same.

[0099] The comprehensive performance test results are shown in Table 2.

[0100]

[0101]

[0102] Table 2

[0103] Experimental results analysis:

[0104] 1. From the data in Table 2, it can be seen that compared with Example 1, the basic indicators such as spiral flow length, bending strength, bending modulus, glass transition temperature, etc. of Comparative Example 1 are almost the same. However, the hot and cold shock test, curing shrinkage, and PCT water absorption of Comparative Example 1 are greatly reduced, proving that the role of silicone-modified epoxy resin glycidyl ether oxypropyl caged polysilsesquioxane is irreplaceable.

[0105] 2. The polyol diluent can balance the wettability of each raw material of the epoxy molding compound, improve the fluidity of the epoxy molding compound, and improve the penetration degree between the epoxy molding compound and the substrate during the heating molding process and the product application process. The data in Table 2 show that the spiral flow length of Comparative Example 2 is reduced to 56 cm, and the processing performance is greatly reduced, which is not conducive to the processing and use of the epoxy molding compound.

[0106] 3. The structure and particle size of powder fillers affect the viscosity, fluidity and stress of epoxy molding compounds. It is a key raw material. It is very important to find the best combination of powder fillers through formula design and scientific matching. The data in Table 2 show that the spiral flow length of comparative example 3 is reduced to 95cm, and the linear expansion coefficient is increased to 23 / 62ppm / K. At the same time, the product's thermal shock performance, curing shrinkage and PCT water absorption rate are reduced to varying degrees, proving that the selection and composition of powder fillers affect the performance of the product.

[0107] 4. The coupling agent plays a role of dispersion and infiltration in the epoxy molding compound, building a bridge between the powder filler and the resin, so that each component is fully mixed and evenly mixed, which is conducive to the comprehensive performance of the formula. Whether the coupling agent is properly selected directly affects the performance of the product. The data in Table 2 show that when the coupling agent KH-550 is replaced by KH-560, the spiral flow length of the product is reduced to 87cm, the linear expansion coefficient is increased, and the thermal shock performance, curing shrinkage rate and PCT water absorption rate are all deteriorated. This shows that the coupling agent KH-550 plays an important role in the formula and is an irreplaceable raw material.

[0108] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A low stress, low shrinkage and high reliability epoxy molding compound, characterized by: The invention comprises the following components by weight: 3.5-12.3 parts of epoxy resin, 0.6-2 parts of organosilicon-modified epoxy resin, 1-2 parts of polyol diluent, 5-6 parts of phenolic resin curing agent, 0.1-0.2 parts of accelerator, 80-85 parts of powder filler, 0.2-0.3 parts of coupling agent, 0.5-0.6 parts of release agent and 0.3-0.4 parts of carbon black; The epoxy resin is a bisphenol A epoxy resin or a phenolic epoxy resin, and the epoxy equivalent is 120 to 230 eq; The organosilicon-modified epoxy resin is a POSS type organosilicon resin, and the POSS type organosilicon resin includes glycidyloxypropyl caged polysilsesquioxane, glycidyloxypropyl cyclotetrasiloxane and octacyclohexylethyl caged polysilsesquioxane; The polyol diluent includes polyether diol, polyester diol and polyester triol; The hydroxyl value of the polyol diluent is 100-320 mgKOH / g; The hydroxyl equivalent of the phenolic resin curing agent is 80-200 g / eq; The powder filler is silicon dioxide and aluminum hydroxide, and the D50 particle size is 0.5-30 microns; The coupling agent is an amino coupling agent.

2. The low stress, low shrinkage and high reliability epoxy molding compound according to claim 1, characterized in that: The accelerator is a latent curing agent, and the latent curing agent includes a tertiary amine latent curing agent and an imidazole latent curing agent.

3. The low stress, low shrinkage and high reliability epoxy molding compound according to claim 1, characterized in that: The release agent is a solid release agent or a liquid release agent.

4. The low stress, low shrinkage and high reliability epoxy molding compound according to claim 1, characterized in that: The polyester diol includes polycaprolactone diol, and the polyester triol includes polycaprolactone triol.

5. A method for preparing a low-stress, low-shrinkage, high-reliability epoxy molding compound according to claim 1, characterized in that: The following steps are involved: Step S1, melt-mixing epoxy resin, organosilicon-modified epoxy resin, phenolic resin curing agent and accelerator at high temperature to obtain epoxy resin prepolymer; Step S2, the epoxy resin prepolymer is cooled and then crushed, the crushed epoxy resin prepolymer powder filler, polyol diluent, coupling agent, release agent and carbon black are mixed, and then the materials are melt-mixed, and the materials are extruded, cooled and crushed to obtain a sheet product; Step S3, the flaky product is crushed and ground into granular powder, which is pressed by a cake making machine to obtain a solid rubber cake, and the product is dried and stored at low temperature.

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