Underfill Adhesive for Encapsulated Chips and Its Preparation Method

Abstract

The present invention discloses an underfill adhesive for encapsulating chips and a preparation method thereof. The underfill adhesive for encapsulating chips comprises 10wt% - 25wt% of organosilicon hybrid epoxy resin, 10wt% - 25wt% of curing agent, 50wt% - 70wt% of inorganic filler, 0.1wt% - 2wt% of curing accelerator and 0.1wt% - 2wt% of coupling agent. This underfill adhesive for encapsulating chips includes organosilicon hybrid epoxy resin, curing agent, inorganic filler, coupling agent and curing accelerator. The organosilicon hybrid epoxy resin has a low surface energy, can effectively reduce the viscosity and fluidity of the system, reduce the modulus, stress and water absorption rate of the cured product, and can achieve the filling of smaller ball pitch and larger size encapsulated chips. In addition, the content of the inorganic filler in this underfill adhesive for encapsulating chips is above 50wt%, and the material properties of low dielectric, low thermal expansion coefficient and low water absorption rate can be achieved, so that the underfill adhesive for encapsulating chips has low stress and high reliability.

Description

Technical Field

[0001] The present invention relates to the field of adhesives, and particularly to an underfill adhesive for encapsulating chips and a preparation method thereof. Background Art

[0002] In the process of flip-chip electronic packaging, the underfill adhesive plays a very important role. Through the filling of the underfill adhesive, a transition layer is formed between the chip and the substrate. On the one hand, the existence of the transition layer can ensure the rigidity of the whole structure and protect the structure; on the other hand, due to the large difference in the coefficient of thermal expansion between the chip and the substrate, the transition layer can also greatly relieve the high stress caused by the mismatch of the coefficient of thermal expansion, providing a guarantee for avoiding various failures in the chip packaging process.

[0003] In traditional underfill adhesives, the content of inorganic fillers is relatively low, which is difficult to meet the requirements of low coefficient of thermal expansion for underfill adhesives in flip chips, and the encapsulation protection effect on flip chips is relatively low. In addition, underfill adhesives with a high content of inorganic fillers have problems such as an increase in the viscosity of the system, poor fluidity, resulting in easy clogging, holes, and uneven dispensing during the dispensing process, and it is difficult to meet the development needs of small chip sizes, small filling pitches, and dense solder ball arrangements in high-density narrow-pitch flip chips.

[0004] Therefore, it is particularly important to develop an underfill adhesive with low viscosity, high fluidity, low coefficient of thermal expansion, and low dielectric constant for further improving the reliability of highly integrated semiconductor devices for communication. Summary of the Invention

[0005] Based on this, it is necessary to provide an underfill adhesive for encapsulating chips with low viscosity, high fluidity, low coefficient of thermal expansion, and low dielectric constant.

[0006] In addition, it is also necessary to provide a preparation method of the above-mentioned underfill adhesive for encapsulating chips.

[0007] An underfill adhesive for encapsulating chips includes 10wt% - 25wt% of organosilicon hybrid epoxy resin, 10wt% - 25wt% of curing agent, 50wt% - 70wt% of inorganic filler, 0.1wt% - 2wt% of curing accelerator, and 0.1wt% - 2wt% of coupling agent.

[0008] In one embodiment, the organosilicon hybrid epoxy resin is selected from at least one of X-40-2678, X-40-2669, X-40-2728, KR470, POSS101 and POSS1010.

[0009] In one embodiment, the silicone hybrid epoxy resin is a mixture of X-40-2669, KR470, and POSS101.

[0010] In one embodiment, the mass ratio of X-40-2669, KR470, and POSS101 is 5 to 9: 0.5 to 8: 0.5 to 3.

[0011] In one embodiment, the curing agent is selected from at least one of tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, nadic anhydride, methylnadic anhydride, trimellitic anhydride, and pyromellitic dianhydride.

[0012] In one embodiment, the inorganic filler is selected from at least one of spherical silica and spherical hollow glass microspheres. The particle size of the spherical silica is 0.1 μm to 20 μm, and the particle size of the spherical hollow glass microspheres is 0.1 μm to 20 μm.

[0013] In one embodiment, the inorganic filler is a mixture of the spherical silica and the spherical hollow glass microspheres, and the mass ratio of the spherical silica to the spherical hollow glass microspheres is 5:1 to 1:5.

[0014] In one embodiment, the curing accelerator is selected from at least one of aluminum acetylacetonate, cobalt acetylacetonate, triphenylphosphine, 2,4,6-tris(dimethylaminomethyl)phenol, 1-cyanoethyl-2-phenyl-4,5-bis(cyanoethylidene)imidazole, and heptadecylimidazole.

[0015] In one embodiment, the coupling agent is selected from at least one of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropyltriethoxysilane, γ-anilinopropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane.

[0016] A method for preparing the bottom filling adhesive for encapsulating chips as described above includes the following steps:

[0017] Stir and mix the silicone hybrid epoxy resin, curing agent, curing accelerator, inorganic filler, and coupling agent to obtain an epoxy resin composite;

[0018] The above epoxy resin composite is passed through a three-roll mill and then ground three times. After that, it is stirred again and subjected to vacuum degassing treatment. Finally, it is filtered and discharged to obtain the required underfill adhesive for encapsulating chips. The underfill adhesive for encapsulating chips includes 10wt% - 25wt% of organosilicon hybrid epoxy resin, 10wt% - 25wt% of curing agent, 50wt% - 70wt% of inorganic filler, 0.1wt% - 2wt% of curing accelerator, and 0.1wt% - 2wt% of coupling agent.

[0019] This underfill adhesive for encapsulating chips includes organosilicon hybrid epoxy resin, curing agent, inorganic filler, coupling agent, and curing accelerator. The organosilicon hybrid epoxy resin has a low surface energy, which can effectively reduce the viscosity and fluidity of the system, decrease the modulus, stress, and water absorption rate of the cured product, and can achieve the filling of encapsulating chips with smaller ball pitches and larger sizes. In addition, the content of inorganic filler in this underfill adhesive for encapsulating chips is above 50wt%, which can achieve the material properties of low dielectric, low coefficient of thermal expansion, and low water absorption rate, making the underfill adhesive for encapsulating chips have low stress and high reliability.

[0020] Combined with the test example part, this underfill adhesive for encapsulating chips has the advantages of low viscosity, high fluidity, low coefficient of thermal expansion, low dielectric, etc., and has obvious advantages compared with traditional underfill adhesives, and can meet the low dielectric and high reliability application requirements of 5G mobile communication high-density encapsulating chips. Detailed implementation mode

[0021] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] The present invention discloses an underfill adhesive for encapsulating chips in an embodiment, which includes 10wt% - 25wt% of organosilicon hybrid epoxy resin, 10wt% - 25wt% of curing agent, 50wt% - 70wt% of inorganic filler, 0.1wt% - 2wt% of curing accelerator, and 0.1wt% - 2wt% of coupling agent.

[0023] This underfill adhesive for encapsulated chips comprises organosilicon hybrid epoxy resin, curing agent, inorganic filler, coupling agent and curing accelerator. The organosilicon hybrid epoxy resin has a low surface energy, which can effectively reduce the viscosity and fluidity of the system, decrease the modulus, stress and water absorption rate of the cured product, and can achieve the filling of encapsulated chips with smaller ball pitches and larger sizes. In addition, the content of inorganic filler in this underfill adhesive for encapsulated chips is above 50wt%, which can achieve the material properties of low dielectric, low thermal expansion coefficient and low water absorption rate, making the underfill adhesive for encapsulated chips have low stress and high reliability.

[0024] Combined with the test example part, this underfill adhesive for encapsulated chips has the advantages of low viscosity, high fluidity, low expansion coefficient, low dielectric, etc., and has obvious advantages compared with traditional underfill adhesives, and can meet the low dielectric and high reliability application requirements of 5G mobile communication high-density encapsulated chips.

[0025] Preferably, in this embodiment, the organosilicon hybrid epoxy resin is selected from at least one of Shin-Etsu X-40-2678, Shin-Etsu X-40-2669, Shin-Etsu X-40-2728, Shin-Etsu KR470, Guangzhou Yixin epoxy-functionalized polyhedral oligomeric silsesquioxane POSS101 and Guangzhou Yixin epoxy-functionalized polyhedral oligomeric silsesquioxane POSS1010.

[0026] More preferably, in this embodiment, the organosilicon hybrid epoxy resin is a mixture of X-40-2669, KR470 and POSS101.

[0027] Specifically, in the organosilicon hybrid epoxy resin, the mass ratio of X-40-2669, KR470 and POSS101 is 5-9:0.5-8:0.5-3.

[0028] Preferably, in this embodiment, the curing agent is selected from at least one of tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, nadic anhydride, methylnadic anhydride, trimellitic anhydride and pyromellitic dianhydride.

[0029] More preferably, in this embodiment, the curing agent is selected from at least one of methyltetrahydrophthalic anhydride, methylnadic anhydride and pyromellitic dianhydride.

[0030] Preferably, in this embodiment, the inorganic filler is selected from at least one of spherical silica and spherical hollow glass microspheres, the particle size of the spherical silica is 0.1μm-20μm, and the particle size of the spherical hollow glass microspheres is 0.1μm-20μm.

[0031] Spherical hollow glass microspheres and spherical silica are more conducive to the underfill adhesive achieving characteristics such as low dielectric constant, low coefficient of thermal expansion, and low water absorption, thereby enabling the underfill adhesive to have low stress and high reliability.

[0032] More preferably, in this embodiment, the inorganic filler is a mixture of spherical silica and spherical hollow glass microspheres, and the mass ratio of spherical silica to spherical hollow glass microspheres is 5:1 to 1:5.

[0033] More preferably, in this embodiment, the content of the inorganic filler is 67 wt%.

[0034] Particularly preferably, in this embodiment, the spherical hollow glass microspheres are surface-modified spherical hollow glass microspheres with an average particle size of 0.1 μm to 10 μm; the spherical silica is surface-modified spherical silica with an average particle size of 0.8 μm to 5 μm.

[0035] Specifically, the surface modifiers used for the above-mentioned surface-modified spherical hollow glass microspheres and surface-modified spherical silica are silane coupling agents, preferably methoxysilane coupling agents, and more preferably γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0036] Preferably, in this embodiment, the curing accelerator is selected from at least one of aluminum acetylacetonate, cobalt acetylacetonate, triphenylphosphine, 2,4,6-tris(dimethylaminomethyl)phenol, 1-cyanoethyl-2-phenyl-4,5-bis(cyanoethylmethylene)imidazole, and heptadecylimidazole.

[0037] More preferably, in this embodiment, the curing accelerator is selected from at least one of aluminum acetylacetonate and triphenylphosphine.

[0038] Preferably, in this embodiment, the coupling agent is selected from at least one of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropyltriethoxysilane, γ-anilinopropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane.

[0039] More preferably, in this embodiment, the coupling agent is selected from at least one of γ-(2,3-epoxypropoxy)propyltrimethoxysilane and γ-anilinopropyltrimethoxysilane.

[0040] The present invention also discloses a preparation method of the above-mentioned underfill adhesive for encapsulating chips in an embodiment, which includes the following steps:

[0041] Mix the silicone hybrid epoxy resin, curing agent, curing accelerator, inorganic filler and coupling agent by stirring to obtain an epoxy resin composite.

[0042] Pass the above epoxy resin composite through a three-roll mill and then grind it three times. After that, stir it again and perform vacuum degassing treatment. Finally, filter and discharge to obtain the required underfill for encapsulating chips.

[0043] The underfill for encapsulating chips comprises 10wt% - 25wt% of silicone hybrid epoxy resin, 10wt% - 25wt% of curing agent, 50wt% - 70wt% of inorganic filler, 0.1wt% - 2wt% of curing accelerator and 0.1wt% - 2wt% of coupling agent.

[0044] The following are specific examples

[0045] Example 1

[0046] S1. Add 100 g of silicone hybrid epoxy resin KR-470 (Shin-Etsu, Japan), 100 g of X-40-2669 (Shin-Etsu, Japan), 190 g of curing agent MH-700G (Shin Nippon Rika), 100 g of spherical hollow glass microspheres (average particle size of 10 μm), 500 g of spherical silica (average particle size of 5 μm), 9.0 g of silane coupling agent KBM-403 (Shin-Etsu, Japan), and 1.0 g of curing accelerator aluminum acetylacetonate into a reaction kettle. Stir at a stirrer speed of 50 rpm and a disperser speed of 200 - 300 rpm for 120 min to obtain epoxy resin composite 1;

[0047] S2. Take out the above epoxy resin composite 1, put it into a three-roll mill for grinding and mixing three times, then transfer it to a double-planet hybrid power stirring kettle and stir for 60 min, and perform vacuum degassing treatment with a vacuum degree < -0.098 MPa. Finally, filter and discharge to obtain underfill 1 for encapsulating chips.

[0048] Example 2

[0049] S1. Add 80 g of silicone hybrid epoxy resin KR-470 (Shin-Etsu, Japan), 80 g of X-40-2669 (Shin-Etsu, Japan), 2.0 g of POSS101 epoxy-functionalized polyhedral oligomeric silsesquioxane (Guangzhou Yixin), 152 g of curing agent MH-700G (Shin Nippon Rika), 170 g of spherical hollow glass microspheres (average particle size of 5 μm), 500 g of spherical silica (average particle size of 5 μm), 13.2 g of silane coupling agent KBM-403 (Shin-Etsu, Japan), and 0.8 g of curing accelerator aluminum acetylacetonate into a reaction kettle. Stir at a stirrer speed of 50 rpm and a disperser speed of 200 - 300 rpm for 120 min to obtain epoxy resin composite 2;

[0050] S2. Take out the above epoxy resin composite 2, put it into a three-roll grinder for grinding and mixing three times, then transfer it to a double planetary hybrid stirring kettle for stirring for 60 min, and conduct vacuum defoaming treatment with a vacuum degree < -0.098 MPa. Finally, filter and discharge to obtain the underfill adhesive 2 for encapsulating chips.

[0051] Example 3

[0052] S1. Add 58 g of organosilicon hybrid epoxy resin KR-470 (Shin-Etsu, Japan), 80 g of X-40-2669 (Shin-Etsu, Japan), 20 g of POSS101 epoxy-functionalized silsesquioxane (Guangzhou Yixin), 160 g of curing agent methyl nadic anhydride, 170 g of spherical hollow glass microspheres (average particle size of 5 μm), 500 g of spherical silica (average particle size of 5 μm), 10.0 of silane coupling agent KBM-573 (Shin-Etsu, Japan), and 2.0 g of curing accelerator triphenylphosphine into a reaction kettle. Stir at a stirrer speed of 50 rpm and a disperser speed of 200 - 300 rpm for 120 min to obtain epoxy resin composite 3;

[0053] S2. Take out the above epoxy resin composite 3, put it into a three-roll grinder for grinding and mixing three times, then transfer it to a double planetary hybrid stirring kettle for stirring for 60 min, and conduct vacuum defoaming treatment with a vacuum degree < -0.098 MPa. Finally, filter and discharge to obtain the underfill adhesive 3 for encapsulating chips.

[0054] Example 4

[0055] S1. Add 30 g of organosilicon hybrid epoxy resin KR-470 (Shin-Etsu, Japan), 90 g of X-40-2678 (Shin-Etsu, Japan), 30 g of POSS1010 epoxy-functionalized silsesquioxane, 145 g of methyl nadic anhydride, 200 g of spherical hollow glass microspheres (average particle size of 5 μm), 500 g of spherical silica (average particle size of 5 μm), 15 g of silane coupling agent KBM-573 (Shin-Etsu, Japan), and 0.5 g of curing accelerator aluminum acetylacetonate into a reaction kettle. Stir at a stirrer speed of 50 rpm and a disperser speed of 200 - 300 rpm for 120 min to obtain epoxy resin composite 4;

[0056] S2. Take out the above epoxy resin composite 4, put it into a three-roll grinder for grinding and mixing three times, then transfer it to a double planetary hybrid stirring kettle for stirring for 60 min, and conduct vacuum defoaming treatment with a vacuum degree < -0.098 MPa. Finally, filter and discharge to obtain the underfill adhesive 4 for encapsulating chips.

[0057] Example 5

[0058] S1. Add 50 g of silicone hybrid epoxy resin X-40-2728 (Shin-Etsu, Japan), 50 g of X-40-2669 (Shin-Etsu, Japan), 77 g of POSS1010 epoxy group silsesquioxane (Guangzhou Yixin), 150 g of curing agent methyltetrahydrophthalic anhydride, 10 g of pyromellitic dianhydride, 450 spherical hollow glass beads (average particle size of 5 μm), 200 g of spherical silica (average particle size of 2 μm), 12 g of silane coupling agent KBM-403 (Shin-Etsu, Japan), and 1.0 g of curing accelerator aluminum acetylacetonate into the reaction kettle. Stir at a stirrer speed of 50 rpm and a disperser speed of 200 - 300 rpm for 120 min to obtain epoxy resin composite 5;

[0059] S2. Take out the above epoxy resin composite 5, put it into a three-roll mill for grinding and mixing three times, then transfer it to a double planetary hybrid stirring kettle and stir for 60 min, and perform vacuum degassing treatment with a vacuum degree < -0.098 MPa. Finally, filter and discharge to obtain underfill 5 for encapsulating chips.

[0060] Comparative Example 1

[0061] S1. Add 180 g of bisphenol F diglycidyl ether, 45 g of terminal epoxy polybutadiene, 165 g of MH-700G (New Japan Rika), 600 g of silica (average particle size of 5 μm), 10 g of silane coupling agent KBM-403 (Shin-Etsu, Japan), and 0.5 g of carbon black into the reaction kettle. Stir at a stirrer speed of 50 rpm and a disperser speed of 200 - 300 rpm for 120 min to obtain epoxy resin composite 6;

[0062] S2. Take out the above epoxy resin composite 6, put it into a three-roll mill for grinding and mixing three times, then transfer it to a double planetary hybrid stirring kettle and stir for 60 min, and perform vacuum degassing treatment with a vacuum degree < -0.098 MPa. Finally, filter and discharge to obtain reference epoxy resin underfill 1.

[0063] Comparative Example 2

[0064] S1. Add 250 g of bisphenol F diglycidyl ether, 50 g of liquid polybutadiene (Evonik Polyoil 110), 90 g of m-phenylenediamine, 600 g of silica (average particle size of 5 μm), 5 g of silane coupling agent KBM-403 (Shin-Etsu, Japan), and 5 g of carbon black into the reaction kettle. Stir at a stirrer speed of 50 rpm and a disperser speed of 200 - 300 rpm for 120 min to obtain epoxy resin composite 7;

[0065] S2. Take out the above epoxy resin composite 7, put it into a three-roll mill for grinding and mixing three times, then transfer it to a double planetary hybrid stirring kettle for stirring for 60 min, and perform vacuum degassing treatment with a vacuum degree < -0.098 MPa. Finally, filter and discharge to obtain the reference epoxy resin underfill 2.

[0066] Test Example

[0067] The properties of the underfills for encapsulated chips prepared in the above Examples 1 to 5 and the reference epoxy resin underfills prepared in Comparative Examples 1 to 2 were tested through the following tests, and Table 1 was obtained.

[0068] Viscosity test: Use a Brookfield rotational viscometer at a temperature of 25 °C, with a 52# rotor, a gap of 0.2 mm, and a rotational speed of 10 rpm to test the viscosity value.

[0069] Flow time test: Use two parallel glass plates with a gap of 50 μm, and record the time when the glue flows to the 30 mm position.

[0070] Bonding strength test: Apply 0.2 mg of glue on FR-4, then attach a 1 mm silicon chip on it, place it at room temperature for 5 min, and then cure it. After curing, use DAGE4000 to test the thrust force to obtain the bonding strength.

[0071] Glass transition temperature Tg test: Use the DSC method for testing. Put 10 mg of the sample into the equipment, heat from 25 °C to 300 °C at a heating rate of 10 °C / min, and analyze the obtained curve to obtain the Tg data.

[0072] Coefficient of thermal expansion CTE test: Test according to the standard (ASTM D696-79). Use a Hitachi TMA7300 device, with a detection temperature range of 25 °C to 300 °C, a heating rate of 5 °C / min, and the sample size: Φ6 mm, length 3 mm.

[0073] Modulus test method: Use a DMA7100 dynamic thermomechanical analyzer, adopt the three-point bending method, set the frequency to 2 Hz, with a detection temperature range of 25 °C to 300 °C, a heating rate of 5 °C / min, and the sample size: 70 mm * 12 mm * 3 mm.

[0074] Dielectric constant measurement: Use a radio frequency impedance material analyzer, with a test frequency of 106 Hz. According to the test standard of GB / T1409-2006, test the dielectric constant of the above example samples.

[0075] Double 85 reliability test, tested according to the standard (GB / T5170.5 - 2008), using a damp heat aging test machine, with a temperature of 85°C, a humidity of 85%RH, and a time of 1000h.

[0076] Table 1

[0077]

[0078]

[0079] Comparing the test results in Table 1, it can first be found that for the reference epoxy resin underfill adhesives prepared in Comparative Examples 1 - 2, their flow rate is slow, and the time taken for the same flow length exceeds 220S. While for the underfill adhesives for encapsulated chips prepared in Examples 1 - 5, the time taken is shortened to about 140S, and the fastest can reach 112S. The relative flow rate is doubled, indicating that the underfill adhesive prepared by the present invention has good fluidity and filling properties. This is mainly because the organosilicon hybrid epoxy resin has a low surface energy and is easy to spread and diffuse at the solid interface.

[0080] In addition, the glass transition temperature of the cured products in Examples 1 - 5 is around 150°C, which is significantly higher than the glass transition temperatures of 115°C and 124°C of the cured products in Comparative Examples 1 and 2. This is because the organosilicon hybrid epoxy resin has multi - functional group characteristics, which increases the cross - linking density of the cured product, giving the material a higher glass transition temperature and heat resistance.

[0081] At the same time, the modulus of the underfill adhesives for encapsulated chips prepared in Examples 1 - 5 is between 5.1 - 6.9GPa. Compared with 7.6GPa and 8.1GPa of the comparative examples, the modulus is reduced. In addition, it is also found that after introducing the spherical hollow glass microspheres and organosilicon composition, the dielectric constant of the cured product is greatly reduced, and it has a low Young's modulus and water absorption rate. After 1000h of damp heat aging, there is no cracking or peeling, and it can still work normally. This is mainly because the silicon - oxygen bond in the structure of the organosilicon hybrid epoxy resin has a longer bond length than the C - C bond in the epoxy resin, which is beneficial to the movement of the polymer molecular segments, absorbs the stress generated in environments such as temperature shock, reduces the damage to the chip, and improves the reliability of the device.

[0082] The underfill adhesives for encapsulated chips prepared in Examples 1 - 5 are more suitable for underfilling in large - size chip packaging (CSP), ball grid array packaging (BGA), etc., greatly increasing the packaging efficiency, reliability, and long - term usability.

[0083] The above-described embodiments merely represent several implementation manners of the present invention. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. An underfill adhesive for encapsulating chips, characterized in that, It includes 10 wt% - 25 wt% of organosilicon hybrid epoxy resin, 10 wt% - 25 wt% of curing agent, 50 wt% - 70 wt% of inorganic filler, 0.1 wt% - 2 wt% of curing accelerator, and 0.1 wt% - 2 wt% of coupling agent; The organosilicon hybrid epoxy resin is a mixture of X-40-2669, KR470, and Ecotion® POSS101; The mass ratio of X-40-2669, KR470, and Ecotion® POSS101 is 5 - 9:0.5 - 8:0.5 - 3; The inorganic filler is a mixture of spherical silica and spherical hollow glass microspheres. The particle size of the spherical silica is 0.1 μm - 20 μm, and the particle size of the spherical hollow glass microspheres is 0.1 μm - 20 μm; The mass ratio of the spherical silica to the spherical hollow glass microspheres is 5:1 - 1:

5.

2. The underfill adhesive for encapsulating chips according to claim 1, wherein, The curing agent is selected from at least one of tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, nadic anhydride, methylnadic anhydride, trimellitic anhydride, and pyromellitic dianhydride.

3. The underfill adhesive for encapsulating chips according to claim 1, wherein The curing accelerator is selected from at least one of aluminum acetylacetonate, cobalt acetylacetonate, triphenylphosphine, 2,4,6-tris(dimethylaminomethyl)phenol, 1-cyanoethyl-2-phenyl-4,5-bis(cyanoethylmethylene)imidazole, and heptadecylimidazole.

4. The underfill adhesive for encapsulating chips according to claim 1, wherein, The coupling agent is selected from at least one of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, γ-(2,3-epoxypropoxy)propyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropyltriethoxysilane, γ-anilinopropyltrimethoxysilane, and 3-mercaptopropyltrimethoxysilane.

5. The preparation method of the underfill adhesive for encapsulating chips according to any one of claims 1 to 4, characterized in that, It includes the following steps: Stir and mix the organosilicon hybrid epoxy resin, curing agent, curing accelerator, inorganic filler, and coupling agent to obtain an epoxy resin composite; Pass the above epoxy resin composite through a three-roll mill and grind it three times, then stir again, and perform vacuum defoaming treatment. Finally, filter and discharge to obtain the required underfill for encapsulating chips. The underfill for encapsulating chips includes 10 wt% - 25 wt% of organosilicon hybrid epoxy resin, 10 wt% - 25 wt% of curing agent, 50 wt% - 70 wt% of inorganic filler, 0.1 wt% - 2 wt% of curing accelerator, and 0.1 wt% - 2 wt% of coupling agent.

Images