Encapsulating adhesive for system-in-package and method for preparing the same

Abstract

This invention discloses an encapsulating adhesive for system-in-package (SIIP) and its preparation method. The encapsulating adhesive comprises 3 wt%–10 wt% organic resin, 0.05 wt%–5 wt% toughening agent, 3 wt%–10 wt% curing agent, 0.05 wt%–2 wt% curing accelerator, 75 wt%–90 wt% inorganic filler, and 0.05 wt%–2 wt% coupling agent. Based on the test examples, the encapsulating adhesive for SIIP of this invention, comprising 75 wt%–90 wt% inorganic filler, exhibits low viscosity (≤80 Pa·s), good processability, and after curing, a low coefficient of thermal expansion (≤15 ppm / ℃), low water absorption (≤0.32%), high glass transition temperature (≥180℃), and excellent mechanical and impact resistance properties, thus meeting the needs of high-density microelectronic packaging and system-in-package (SIIP).

Description

Technical Field

[0001] This invention relates to the field of adhesives, and in particular to an encapsulating adhesive for system-level encapsulation and its preparation method. Background Technology

[0002] System-in-Package (SiP) is a high-density integration technology that integrates different active chips and passive devices into a single package to form a system or subsystem. It effectively reduces product size, achieves high-density integration and miniaturization, while also reducing costs and meeting various performance requirements and complex heterogeneous integration needs. As system requirements for performance, power consumption, and density increase, SiP is increasingly using 2.5D / 3D / wafer-level advanced packaging processes. Coupled with the recently popular chiplet technology (where different functional circuits are packaged into individual chips), advanced packaging technologies led by 3D-IC have achieved a good balance between SoC and PCB, and have become one of the hottest technologies in the industry, playing a vital role in wireless communications, automotive electronics, medical electronics, artificial intelligence, and military electronics.

[0003] However, as a new direction for the development of integrated circuits in the post-Moore era, system-in-package (SIP) technology is currently facing a series of challenges, such as the control of multiple physical fields, the coordination of multiple performances, and the integration of multiple materials. Due to the differences in the expansion coefficients of different devices and chips, it is necessary to establish heterogeneous interface dynamics and bonding mechanisms, and achieve highly reliable heterogeneous integration through interface control and integration. This places higher demands on the encapsulating adhesive.

[0004] Traditional solid epoxy encapsulation materials are solid and are mainly formed through injection molding under heat, requiring high temperatures and certain pressures. This process has a certain impact on the solder joints of multi-chip devices and cannot meet the requirements of system-in-package (SIPP). US6117953 discloses a method for preparing a liquid epoxy encapsulant for semiconductors. This liquid epoxy encapsulant is composed of bisphenol A type epoxy, alicyclic epoxy and their epoxy resins, anhydride curing agents, etc. The glass transition temperature of the cured resin is in the range of 150-160℃, and the warpage is less than 85µm. However, its water absorption rate is relatively high (0.79-0.92%), and its resistance to damp heat is poor. US 5439977 discloses an epoxy encapsulant with good shelf life and flowability, but the heat resistance of the cured resin is low, and the glass transition temperature is only 100-110℃.

[0005] In response to the problems existing in current encapsulating adhesives, it is urgent to develop an encapsulating adhesive with low coefficient of thermal expansion, low stress, low water absorption, and high glass transition temperature, so that electronic components can work stably within the normal temperature range. Summary of the Invention

[0006] Therefore, it is necessary to provide an encapsulating adhesive for system-level encapsulation with low coefficient of thermal expansion, low stress, low water absorption, and high glass transition temperature.

[0007] In addition, it is necessary to provide a method for preparing the above-mentioned encapsulating adhesive for system-level encapsulation.

[0008] An encapsulating adhesive for system-level encapsulation comprises 3 wt% to 10 wt% organic resin, 0.05 wt% to 5 wt% toughening agent, 3 wt% to 10 wt% curing agent, 0.05 wt% to 2 wt% curing accelerator, 75 wt% to 90 wt% inorganic filler, and 0.05 wt% to 2 wt% coupling agent.

[0009] In one embodiment, the organic resin is selected from at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexyl carboxylate, 3-epoxyethylene 7-oxabicyclo[4.1.0]heptane, bis((3,4-epoxycyclohexyl)methyl)adipate, 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester, 1,4-cyclohexanediethanol bis(3,4-epoxycyclohexane carboxylate), triglycidyl p-aminophenol, 4,4'-bis(2,3-epoxypropoxy)biphenyl, hydantoin epoxy resin, bisphenol A type cyanate, bisphenol F type cyanate, bisphenol E type cyanate, bisphenol M type cyanate, dicyclopentadiene type cyanate, and phenolic type cyanate resin.

[0010] In one embodiment, the toughening agent is selected from at least one of organosilicon hybrid epoxy resin and epoxy oligomeric silsesquioxane.

[0011] In one embodiment, the curing agent is selected from at least one of methylhexahydrophthalic anhydride, modified methyltetrahydrophthalic anhydride, methylnadic anhydride, modified trimellitic anhydride, and alkenyl-substituted succinic anhydride.

[0012] In one embodiment, the curing accelerator is selected from at least one of 1,8-diazabicycloundec-7-ene, 1,5-diazabicyclo[4.3.0]nonene, 5,6-dibutylamino-1,8-diazabicyclo[5.4.0]undecene-7, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenyl-4,5-di(cyanoethylmethylene)imidazole, heptadecanylimidazole, and 2,4-diamino-6[2'-methylimidazole-(1')]ethyl-S-triazine.

[0013] In one embodiment, the inorganic filler is selected from at least one of spherical silica and spherical alumina.

[0014] In one embodiment, the particle size of the spherical alumina is 0.5 μm to 20 μm.

[0015] In one embodiment, the particle size of the spherical silica is 0.1 μm to 10 μm.

[0016] In one embodiment, the coupling agent is selected from at least one of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, (3-epoxypropoxypropyl)triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropyltriethoxysilane, and γ-anilinopropyltrimethoxysilane.

[0017] A method for preparing the above-mentioned encapsulating adhesive for system-level encapsulation includes the following steps:

[0018] Organic resin, toughening agent, curing agent, curing accelerator, inorganic filler and coupling agent are stirred and mixed to obtain epoxy resin composite;

[0019] The epoxy resin composite was passed through a three-roll mill and ground three times, then stirred again and subjected to vacuum degassing. Finally, it was filtered and discharged to obtain the required underfill adhesive for encapsulation chips. The encapsulation adhesive for system-level encapsulation includes 3wt% to 10wt% of the organic resin, 0.05wt% to 5wt% of the toughening agent, 3wt% to 10wt% of the curing agent, 0.05wt% to 2wt% of the curing accelerator, 75wt% to 90wt% of the inorganic filler, and 0.05wt% to 2wt% of the coupling agent.

[0020] Based on the test examples, the encapsulating adhesive for system-in-package of the present invention comprises 75wt% to 90wt% inorganic filler, has low viscosity (≤80Pa·S), good processability, and after curing, has a low coefficient of thermal expansion (≤15ppm / ℃), low water absorption (≤0.32%), high glass transition temperature (≥180℃), as well as excellent mechanical properties and impact resistance, which can meet the needs of high-density microelectronic packaging and system-in-package.

[0021] Furthermore, the encapsulant for system-level encapsulation of the present invention employs a modified anhydride curing system, which significantly reduces the volatility of the anhydride and maintains a low viscosity of the system, achieving high filling of inorganic powder and effectively reducing the coefficient of thermal expansion of the liquid encapsulation material. At the same time, the introduction of low surface energy organosilicon hybrid epoxy resin reduces the modulus and stress of the cured product, effectively reducing the water absorption rate of the system, significantly improving the heat resistance of the system, and reducing the water absorption rate and stress of the system, thereby obtaining a low-stress, moisture-resistant liquid encapsulation material, which has obvious advantages compared with traditional solid epoxy encapsulation materials, meeting the application requirements of high fluidity and high reliability in system-level encapsulation. Detailed Implementation

[0022] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] The present invention discloses an embodiment of a system-level encapsulating adhesive, comprising 3 wt% to 10 wt% organic resin, 0.05 wt% to 5 wt% toughening agent, 3 wt% to 10 wt% curing agent, 0.05 wt% to 2 wt% curing accelerator, 75 wt% to 90 wt% inorganic filler, and 0.05 wt% to 2 wt% coupling agent.

[0024] Based on the test examples, the encapsulating adhesive for system-in-package (SIIP) of this invention comprises 75 wt% to 90 wt% inorganic filler, has low viscosity (≤80 Pa·S), good processability, and after curing, exhibits a low coefficient of thermal expansion (≤15 ppm / ℃), low water absorption (≤0.32%), high glass transition temperature (≥180℃), as well as excellent mechanical properties and impact resistance, thus meeting the needs of high-density microelectronic packaging and system-in-package.

[0025] Preferably, in this embodiment, the organic resin is selected from at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexyl carboxylate, 3-epoxyethylene 7-oxabicyclo[4.1.0]heptane, bis((3,4-epoxycyclohexyl)methyl)adipate, 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester, 1,4-cyclohexanediethanol bis(3,4-epoxycyclohexane carboxylate), triglycidyl p-aminophenol, 4,4'-bis(2,3-epoxypropoxy)biphenyl, hydantoin epoxy resin, bisphenol A type cyanate, bisphenol F type cyanate, bisphenol E type cyanate, bisphenol M type cyanate, dicyclopentadiene type cyanate, and phenolic type cyanate resin.

[0026] More preferably, in this embodiment, the organic resin is selected from at least one of liquid bisphenol A type epoxy resin, liquid bisphenol F type epoxy resin, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate, p-aminophenol type liquid epoxy resin and bisphenol E type cyanate.

[0027] Preferably, in this embodiment, the toughening agent is selected from at least one of organosilicon hybrid epoxy resin and epoxy oligomeric silsesquioxane.

[0028] The organosilicon hybrid epoxy resin can be Kanekazu MX962, Shin-Etsu X-40-2678, Shin-Etsu X-40-2669, Shin-Etsu X-40-2728 or Shin-Etsu KR470 from Japan, and the epoxy-based oligomeric silsesquioxane can be EP0409 from HybridPlastics, USA.

[0029] Among them, Kanekachi MX962 from Japan and EP0409 from Hybrid Plastics in the United States are preferred due to their core-shell structure, which has good heat resistance and impact resistance.

[0030] More preferably, in this embodiment, the toughening agent is a mixture of organosilicon hybrid epoxy resin and epoxy oligomeric silsesquioxane in a mass ratio of 1:0.8 to 3.

[0031] Preferably, in this embodiment, the toughening agent content is 0.1wt% to 3wt%.

[0032] Preferably, in this embodiment, the curing agent is selected from at least one of methylhexahydrophthalic anhydride (S816, LD-GX60), modified methyltetrahydrophthalic anhydride JH-0611, methylnadic anhydride JH-0630, modified trimellitic anhydride, and alkenyl-substituted succinic anhydride.

[0033] Modified anhydride curing agents exhibit excellent moisture resistance and thermal cycling resistance, while modified methylhexahydrophthalic anhydride S816 and methylnadic anhydride demonstrate good storage stability.

[0034] Preferably, in this embodiment, the curing accelerator is selected from at least one of 1,8-diazabicycloundec-7-ene, 1,5-diazabicyclo[4.3.0]nonene, 5,6-dibutylamino-1,8-diazabicyclo[5.4.0]undecene-7, 2-ethyl-4-methylimidazolium, 2-phenylimidazolium, 1-cyanoethyl-2-methylimidazolium, 1-cyanoethyl-2-phenyl-4,5-di(cyanoethylmethylene)imidazolium, heptadecanylimidazolium, and 2,4-diamino-6[2'-methylimidazolium-(1')]ethyl-S-triazine.

[0035] Preferably, in this embodiment, the content of the curing accelerator is 0.05wt% to 2wt%.

[0036] More preferably, in this embodiment, the content of the curing accelerator is 0.1wt% to 0.5wt%.

[0037] If the curing accelerator dosage is less than 0.05%, the curing properties tend to deteriorate in a short time; if the curing accelerator dosage is higher than 2%, the curing speed is too fast, making it difficult to obtain molded parts with good shapes.

[0038] Preferably, in this embodiment, the inorganic filler is selected from at least one of spherical silica and spherical alumina, wherein the particle size of the spherical alumina is 0.5 μm to 20 μm, and the particle size of the spherical silica is 0.1 μm to 10 μm.

[0039] More preferably, in this embodiment, the inorganic filler is a mixture of spherical silica and spherical alumina in a mass ratio of 0.9 to 1.5:1.

[0040] In a particularly preferred embodiment, the spherical alumina is surface-modified spherical alumina with an average particle size of 1 μm to 10 μm; and the spherical silica is surface-modified spherical silica with an average particle size of 0.8 μm to 5 μm.

[0041] Specifically, the surface modification of the surface-modified spherical alumina and surface-modified spherical silica uses a silane coupling agent, preferably a methoxysilane coupling agent, and more preferably γ-(2,3-epoxypropoxy)propyltrimethoxysilane.

[0042] Preferably, in this embodiment, the coupling agent is selected from at least one of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, (3-epoxypropoxypropyl)triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropyltriethoxysilane, and γ-anilinepropyltrimethoxysilane.

[0043] Preferably, in this embodiment, the content of the coupling agent is 0.05wt% to 2wt%.

[0044] More preferably, in this embodiment, the content of the coupling agent is 0.5wt% to 1.5wt%.

[0045] If the content of coupling agent is less than 0.1%, the moldability and moisture resistance will decrease; if the content of coupling agent is more than 2%, a certain degree of thixotropy will occur, resulting in poorer system fluidity and reduced adhesion.

[0046] The encapsulant for system-level packaging of this invention adopts a modified anhydride curing system, which significantly reduces the volatility of the anhydride and maintains a low viscosity of the system, achieving high filling of inorganic powder and effectively reducing the coefficient of thermal expansion of the liquid encapsulation material. At the same time, the introduction of low surface energy organosilicon hybrid epoxy resin reduces the modulus and stress of the cured product, which can effectively reduce the water absorption rate of the system, significantly improve the heat resistance of the system, and reduce the water absorption rate and stress of the system, thereby obtaining a low-stress, moisture-resistant liquid encapsulation material. Compared with traditional solid epoxy encapsulation materials, it has obvious advantages and meets the application requirements of high fluidity and high reliability of system-level packaging.

[0047] The present invention also discloses a method for preparing the above-described encapsulating adhesive for system-level encapsulation according to one embodiment, comprising the following steps:

[0048] Organic resin, toughening agent, curing agent, curing accelerator, inorganic filler and coupling agent are stirred and mixed to obtain epoxy resin composite;

[0049] The epoxy resin composite was passed through a three-roll mill and ground three times, then stirred again and subjected to vacuum degassing. Finally, it was filtered and discharged to obtain the bottom filler for the encapsulated chip.

[0050] The resulting encapsulant for system-level encapsulation comprises 3 wt% to 10 wt% organic resin, 0.05 wt% to 5 wt% toughening agent, 3 wt% to 10 wt% curing agent, 0.05 wt% to 2 wt% curing accelerator, 75 wt% to 90 wt% inorganic filler, and 0.05 wt% to 2 wt% coupling agent.

[0051] The following are specific embodiments.

[0052] Example 1

[0053] S1. Add 35g of bisphenol F epoxy resin YD8170, 20g of bisphenol A epoxy resin YD8125, 15g of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate CELLOXIDE2021P, 12g of toughening agent MX962, 60g of curing agent S816, 850g of spherical silica SEC-4050, 5g of silane coupling agent KBM-403 (Shin-Etsu Chemical, Japan), and 3.0g of accelerator DBU to the reactor. Stir for 120 minutes at a stirrer speed of 50 rpm and a disperser speed of 1200-1500 rpm.

[0054] S2. Take out the above mixture, put it into a three-roll mill for grinding, then transfer it to a double planetary hybrid mixing tank and stir for 60 minutes. Perform vacuum degassing treatment with a vacuum degree of <-0.098MPa. Finally, filter and discharge to obtain encapsulating adhesive 1 for system-level encapsulation.

[0055] Example 2

[0056] S1. Add 20g of 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate CELLOXIDE2021P (Japan Daicel), 40g of bisphenol E cyanate, 8g of toughening agent MX962, 20g of curing agent methyl nadic anhydride, 900g of spherical alumina AZ2-75 (Nippon Steel), 10g of silane coupling agent KBM-403 (Japan Shin-Etsu), and 2g of accelerator DBU to the reactor. Stir for 120min at a stirrer speed of 50rpm and a disperser speed of 1200-1500rpm.

[0057] S2. Take out the above mixture and put it into a three-roll mill for grinding and mixing three times. Then transfer it to a double planetary hybrid mixing tank and stir for 60 minutes. Perform vacuum degassing treatment with a vacuum degree of <-0.098MPa. Finally, filter and discharge to obtain encapsulating adhesive 2 for system-level encapsulation.

[0058] Example 3

[0059] S1. Add 30g CELLOXIDE2021P (Japan Caillu), 53g bisphenol E cyanate, 4g toughening agent epoxy silsesquioxane EP0409, 30g curing agent methyl nadic anhydride, 870g spherical silica SC-220G-SQ, 10g silane coupling agent KBM-403 (Japan Shin-Etsu), and 3g accelerator MZ-A to the reactor. Stir for 120 minutes with a stirrer speed of 50 rpm and a disperser speed of 1200-1500 rpm.

[0060] S2. Take out the above mixture, put it into a three-roll mill for grinding, then transfer it to a double planetary hybrid mixing tank and stir for 60 minutes. Perform vacuum degassing treatment with a vacuum degree of <-0.098MPa. Finally, filter and discharge to obtain the encapsulating adhesive 3 for system-level encapsulation.

[0061] Example 4

[0062] S1. Add 40g of bisphenol F epoxy resin YD8170, 25g of triglycidyl p-aminophenol AG-90, 10g of toughening agent epoxy silsesquioxane EP0409, 10g of toughening agent X-40-2669, 75g of curing agent methyl nadic anhydride, 830g of spherical silica SC-220G-SQ, 7g of silane coupling agent KBM-403 (Shin-Etsu Chemical, Japan), and 3g of accelerator MZ-A to the reactor. Stir for 120 minutes at a stirrer speed of 50 rpm and a disperser speed of 1200-1500 rpm.

[0063] S2. Take out the above mixture, put it into a three-roll mill for grinding, then transfer it to a double planetary hybrid mixing tank and stir for 60 minutes. Perform vacuum degassing treatment with a vacuum degree of <-0.098MPa. Finally, filter and discharge to obtain the encapsulating adhesive 4 for system-level encapsulation.

[0064] Example 5

[0065] S1. Add 35g of bisphenol F epoxy resin YD8170, 15g of CELLOXIDE2021P (Japan Daicel), 15g of triglycidyl p-aminophenol AG-90, 5g of toughening agent epoxy silsesquioxane EP0409, 10g of toughening agent MX962, 63g of curing agent S816, 450g of spherical silica SC-220G-SQ, 400g of spherical alumina ASFP-20, 5g of γ-anilinepropyltrimethoxysilane, and 2g of accelerator 2-phenylimidazole to the reactor. Stir for 120 minutes at a stirrer speed of 50 rpm and a disperser speed of 1200-1500 rpm.

[0066] S2. Take out the above mixture, put it into a three-roll mill for grinding, then transfer it to a double planetary hybrid mixing tank and stir for 60 minutes. Perform vacuum degassing treatment with a vacuum degree of <-0.098MPa. Finally, filter and discharge to obtain the encapsulating adhesive 5 for system-level encapsulation.

[0067] Comparative Example 1

[0068] S1. Add 75g of bisphenol A diglycidyl ether YD8125, 15g of toughening agent MX154, 69g of MH-700G (New Japan Rika), 830g of spherical silica SEC-4050, 10g of silane coupling agent KBM-403 (Shin-Etsu Chemicals, Japan), and 1.0g of accelerator 2E4MZ to the reactor. Stir for 120 minutes at a stirrer speed of 50 rpm and a disperser speed of 1200-1500 rpm.

[0069] S2. Take out the above epoxy resin composite, put it into a three-roll mill for grinding, then transfer it to a double planetary hybrid stirring tank and stir for 60 minutes. Perform vacuum degassing treatment with a vacuum degree of <-0.098MPa. Finally, filter and discharge to obtain the reference liquid encapsulation material 1.

[0070] Comparative Example 2

[0071] S1. Add 60g of bisphenol F diglycidyl ether YD8170, 15g of CELLOXIDE2021P (Japan Daicel), 15g of toughening agent MX154, 69g of MH-700G (New Japan Rika), 850g of spherical silica SC-220G-SQ, 10g of silane coupling agent KBM-403 (Japan Shin-Etsu), and 1.0g of accelerator 2E4MZ to the reactor. Stir for 120 minutes at a stirrer speed of 50 rpm and a disperser speed of 200-300 rpm.

[0072] S2. Take out the above epoxy resin composite, put it into a three-roll mill for grinding, then transfer it to a double planetary hybrid stirring tank and stir for 60 minutes. Perform vacuum degassing treatment with a vacuum degree of <-0.098MPa. Finally, filter and discharge to obtain the reference liquid encapsulation material 2.

[0073] Test case

[0074] The performance of the encapsulating adhesives for system-level packaging prepared in Examples 1 to 5 and the reference liquid encapsulating materials prepared in Comparative Examples 1 to 2 were tested through the following experiments, and the results are shown in Table 1.

[0075] Viscosity test: The viscosity value was measured using a Brookfield rotational viscometer at 25°C, with a 52# rotor, a gap of 0.2 mm, and a rotation speed of 10 rpm.

[0076] Flow time test: Using two parallel glass plates with a gap of 50μm, the time it takes for the adhesive to flow to a position of 30mm is recorded.

[0077] Adhesion strength test: Apply 0.2mg of adhesive to FR-4, then attach a 1mm silicon chip on top, leave at room temperature for 5 minutes, and then cure. After curing, use DAGE4000 to test the push force to obtain the adhesion strength.

[0078] Glass transition temperature (Tg) test: The DSC method was used. 10 mg of sample was placed in the equipment, and the temperature ranged from 25 to 300 °C. The heating rate was 10 °C / min. The Tg data could be obtained by analyzing the obtained curve.

[0079] Linear thermal expansion coefficient (CTE) test: Tested according to standard (ASTM D696-79) using Hitachi TMA7300 equipment, with a test temperature range of 25~300℃, a heating rate of 5℃ / min, and sample size: Φ6mm, length 3mm.

[0080] Double 85 reliability test: Tested according to standard (GB / T5170.5-2008) using a damp heat aging test chamber, temperature 85℃, humidity 85%RH, time 1000h.

[0081] Thermal shock test: Tested according to standard (GB / T5170.5-2008) using a temperature cycling aging test chamber, temperature -55℃ / 15min, 125℃ / 15min, 700 cycles.

[0082] Table 1

[0083]

[0084]

[0085] As can be seen from Table 1, the encapsulating adhesives for system-in-package prepared in Examples 1 to 5 have low viscosity (≤80 Pa·S), good processability, low coefficient of thermal expansion (≤15 ppm / ℃), low water absorption (≤0.32%), high glass transition temperature (≥180℃) after curing, as well as excellent mechanical properties and impact resistance, which can meet the needs of high-density microelectronic packaging and system-in-package.

[0086] Furthermore, the liquid encapsulation materials prepared by modifying the encapsulating adhesive with anhydride curing agent in Examples 1-5 exhibit good fluidity and low volume shrinkage, mainly due to the reduced volatility of the modified anhydride curing agent. In addition, the introduction of hybrid silicone epoxy resin, due to the multifunctionality of silicone, increases the crosslinking density of the cured product, imparting a higher glass transition temperature and temperature resistance to the material, and significantly reducing the water absorption rate of the system. This significantly improves the system's resistance to damp heat and thermal shock. After 1000 hours of damp heat aging and 700 thermal shocks, the bonding surface did not crack or peel, and the device could still function normally.

[0087] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A system-level encapsulating adhesive, characterized in that, It includes 3wt% to 10wt% organic resin, 0.05wt% to 5wt% toughening agent, 3wt% to 10wt% curing agent, 0.05wt% to 2wt% curing accelerator, 75wt% to 90wt% inorganic filler and 0.05wt% to 2wt% coupling agent; The inorganic filler is selected from at least one of spherical silica and spherical alumina, wherein the particle size of the spherical alumina is 0.5 μm to 20 μm, and the particle size of the spherical silica is 0.1 μm to 10 μm; The toughening agent is a mixture of organosilicon hybrid epoxy resin and epoxy oligomeric silsesquioxane in a mass ratio of 1:0.8-3, wherein the organosilicon hybrid epoxy resin is Kanekachi MX962, Shin-Etsu X-40-2678, Shin-Etsu X-40-2669, Shin-Etsu X-40-2728 or Shin-Etsu KR470. The organic resin is selected from at least one of bisphenol A type epoxy resin, bisphenol F type epoxy resin, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexyl carboxylate, 3-epoxyethylene 7-oxabicyclo[4.1.0]heptane, bis((3,4-epoxycyclohexyl)methyl)adipate, 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester, 1,4-cyclohexanediethanol bis(3,4-epoxycyclohexane carboxylate), triglycidyl p-aminophenol, 4,4'-bis(2,3-epoxypropoxy)biphenyl, and hydantoin epoxy resin; or The organic resin is 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexylcarboxylate and bisphenol E cyanate; The curing agent is selected from at least one of curing agent S816 and methyl nadic anhydride.

2. The encapsulating adhesive for system-level encapsulation according to claim 1, characterized in that, The curing accelerator is selected from at least one of 1,8-diazabicycloundec-7-ene, 1,5-diazabicyclo[4.3.0]nonene, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, heptadecanylimidazole and 2,4-diamino-6[2'-methylimidazole-(1')]ethyl-S-triazine.

3. The encapsulating adhesive for system-level packaging according to claim 1, characterized in that, The coupling agent is selected from at least one of 3-(2,3-epoxypropoxy)propyltrimethoxysilane, (3-epoxypropoxypropyl)triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-aminoethyl-3-aminopropyltriethoxysilane, and γ-anilinopropyltrimethoxysilane.

4. A method for preparing a system-level encapsulating adhesive according to any one of claims 1 to 3, characterized in that, Includes the following steps: Organic resin, toughening agent, curing agent, curing accelerator, inorganic filler and coupling agent are stirred and mixed to obtain epoxy resin composite; The epoxy resin composite was passed through a three-roll mill and ground three times, then stirred again and subjected to vacuum degassing. Finally, it was filtered and discharged to obtain the required bottom filler for the encapsulation chip, namely the encapsulation adhesive for system-level packaging.

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