Bottom filling adhesive for flip chip and preparation method of bottom filling adhesive

Abstract

The invention relates to an underfill adhesive for flip chips, which is prepared from the following raw materials in parts by mass: 22-30 parts of bifunctional epoxy resin, 5-8 parts of polyfunctional epoxy resin, 10-14 parts of polyether modified flexible epoxy resin, 7-10 parts of trifunctional maleimide compound shown in a formula (I), 4-7 parts of curing agent containing more than two amino groups and 3-4 parts of low molecular weight polyamide, 1-3 parts of a coupling agent, 0.5-2 parts of a curing accelerator and 100 parts of coupling agent modified spherical silica powder. The underfill adhesive provided by the invention has very good fluidity, relatively high Tg, proper mechanical strength and excellent warping resistance, also has high-temperature-resistant and damp-heat-resistant aging resistance and excellent moisture resistance, and can be applied to various high-temperature / high-humidity scenes.

Description

Technical Field

[0001] The invention belongs to the technical field of epoxy glue, and in particular relates to a bottom filling glue for a flip chip and a preparation method thereof. Background Art

[0002] Flip chip is a new type of chip that deposits solder balls on the I / O circuit board, flips the chip and heats it, and uses the molten solder balls and ceramics to form a basic bond. Unlike traditional chip packaging technology where the active area faces upward, flip chip packaging has the active area facing the substrate, which increases the I / O density and achieves more I / Os. Due to its advantages of small lead inductance, small signal interference, and short connection delay, flip chip has become the mainstream technology for semiconductor packaging. With the development of semiconductor integration technology, the size of circuit design is getting smaller and smaller, and the integration is getting higher and higher, which will cause the tea to be overweight in a larger temperature difference environment. The difference in thermal expansion coefficients of chips, substrates, and solder joints will be magnified in small chips. Especially under periodic temperature conditions, or high temperature and high humidity environments, chips are prone to fatigue damage. Higher quality requirements are placed on the glue used for flip chip packaging.

[0003] Under the action of capillary, the epoxy glue flowing fills the gap between the chip and the substrate. As an important electronic adhesive for integrated circuit packaging, underfill glue alleviates the problem of mismatch of thermal expansion coefficients between different materials in chip packaging and improves the reliability of device packaging. The choice of underfill glue plays a decisive role in the filling effect. The underfill for flip chip needs to have good fluidity, high glass transition temperature (Tg), suitable curing time, and excellent mechanical properties. In addition, since some electronic components may work under high temperature and high humidity, the underfill glue is also required to have high temperature and high humidity resistance.

[0004] CN113403013A discloses a bottom filling glue for semiconductor packaging, comprising epoxy resin, filler, curing agent, toughening agent and accelerator, characterized in that: in the bottom filling glue with high elongation at break, the content of the epoxy resin is 13-20wt%, the content of the filler is 60-65wt%, the content of the curing agent is 10-20wt%, the content of the toughening agent is 5-15wt%, the content of the accelerator is 0.5-0.8wt%, and the toughening agent is a methyl methacrylate-butadiene-styrene terpolymer. This terpolymer is easily dispersed in the epoxy resin system, and can still effectively reduce the crosslinking density of the epoxy resin at a high temperature above 200°C, thereby improving the toughness of the bottom filling glue.

[0005] Due to the rapid development of semiconductor integrated circuit technology, chip stacking has evolved from 2D, 2.5D to today’s 3D stacking technology, and the local power density has increased rapidly, reaching 100W / cm 2 The above will cause the temperature to rise sharply, so efficient heat dissipation and thermal stability are also required for the bottom filler. The use of maleimide resin in the bottom filler can increase thermal stability. The presence of the five-membered ring of the imide plane hinders the rotation of the polymer chain and hinders the movement of the polymer chain. Therefore, adding maleimide to the epoxy glue through curing can give the glue excellent heat resistance.

[0006] CN117777918A, CN116875243A, CN116120348A, and CN115678476A all involve the use of maleimide resins. However, these maleimide resins or compounds are all bifunctional and cannot fully exert the effect of maleimide resins. The inventor's previous patent CN202411860890.3 discloses an anti-warping bottom filling glue, which uses a polymer resin with maleimide as the side chain and end group to improve the anti-warping performance at high temperature. However, its moisture and heat resistance is not good and needs further improvement. Summary of the invention

[0007] In order to solve the problem that the comprehensive performance of the bottom filling glue used for flip chips in the prior art is not good enough and it is difficult to take into account both mechanical properties and aging resistance, the present invention proposes a bottom filling glue for flip chips that can resist wet and hot aging, wherein a self-made trifunctional maleimide compound is used to give the bottom filling glue high temperature resistance, wet and hot weather resistance. Specifically, the present invention proposes the following technical solutions to solve the above problems:

[0008] A bottom filling glue for flip chip, comprising the following raw materials in parts by mass: 22-30 parts of a bifunctional epoxy resin, 5-8 parts of a multifunctional epoxy resin, 10-14 parts of a polyether-modified flexible epoxy resin, 7-10 parts of a trifunctional maleimide compound represented by formula (I), 4-7 parts of a curing agent containing more than two amine groups, 3-4 parts of a low molecular weight polyamide, 1-3 parts of a coupling agent, 0.5-2 parts of a curing accelerator, and 100 parts of coupling agent-modified spherical silica powder;

[0009]

[0010] Furthermore, the trifunctional maleimide compound shown in formula (I) is obtained by reacting 2,3,5-triamino-1,4-naphthoquinone with maleic anhydride to obtain maleimide acid, and then dehydrating it. Preferably, the dehydration is carried out under anhydride conditions, the anhydride is selected from at least one of acetic anhydride and phosphoric anhydride, and the molar ratio of 2,3,5-triamino-1,4-naphthoquinone, maleic anhydride and anhydride is 1:3.5-4:5-6.

[0011] Furthermore, the trifunctional maleimide compound shown in formula (I) is prepared by a preparation method comprising the following steps: 2,3,5-triamino-1,4-naphthoquinone and maleic anhydride are reacted in an ice-water bath for 4-6 hours, after the reaction, anhydride is added under an inert atmosphere, the temperature is raised to 120-130°C for dehydration reaction, after the reaction is completed, the temperature is lowered to 35-45°C, the product is poured into product ice water, filtered, the filter cake is dried, and recrystallized to obtain the product compound of formula (I).

[0012] The inert atmosphere is nitrogen and / or argon, the volume of ice water is 10-15 times of the product volume, and ethanol is used for recrystallization.

[0013] Furthermore, the bifunctional epoxy resin is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and biphenyl epoxy resin, and the epoxy value is 0.3-0.5.

[0014] Furthermore, the bisphenol A epoxy resin is selected from at least one of E35, E41, E44, and NPEL-128E; the bisphenol F epoxy resin is selected from JER807 epoxy resin, EPIKOTE At least one of 862 epoxy resin, EPICLON830 epoxy resin, EPICLON830S epoxy resin, EPICLON835 epoxy resin, CYDF-170, GEFR170, NPEF-170, CYDF-180, YDF2001, and YDF2004; the biphenyl epoxy resin is selected from at least one of JSR's YX4000, JER-YX4000, JER-YX4000K, JER-YX4000H, JER-YL6121HA, Nippon Kayaku NC3000, Japan DIC brand HP-5000, Jiashengde BPNE3501, and Jiashengde NPTE4000.

[0015] The multifunctional epoxy resin has three or more epoxy groups, and is specifically selected from at least one of triglycidyl p-aminophenol, 4,4'-diaminodiphenylmethane tetraglycidylamine epoxy resin, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl ether, N,N,N',N'-tetraglycidyl-1,4-diaminobenzene, N,N,N',N'-tetraglycidyl-1,3-diaminobenzene, isocyanuric acid triglycidylamine, N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane, tetraglycidyldiaminodiphenylmethane, tetraphenylglycidyl ether methane, and tetraglycidyl hydrogenated meta-phenylenediamine.

[0016] The polyether-modified flexible epoxy resin is selected from at least one of polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether, wherein the number average molecular weight of the polyether segment is 400-600.

[0017] Furthermore, the curing agent containing more than two amine groups is selected from at least one of 3,3'-diethyl 4,4'-diaminodiphenylmethane, diethyltoluenediamine, diaminodiphenylmethane, 3,-ethyl-4,4'-diaminodiphenylmethane, 2,4-diamino-3,5-dimethylthiotoluene, hendiamine, trimethylhexanediamine, m-phenylenediamine, and diaminodiphenyl ether.

[0018] Furthermore, the coupling agent is at least one of an epoxy silane coupling agent, an amino silane coupling agent, and a urea silane coupling agent.

[0019] Furthermore, the epoxy silane coupling agent is selected from at least one of γ-glycidyloxypropyl trimethoxysilane, γ-glycidyloxypropyl triethoxysilane, and γ-glycidyloxypropyl methyl diethoxysilane; the amino silane coupling agent is selected from at least one of 3-(phenylamino)propyl trimethoxysilane, NN diethylaminopropyl trimethoxysilane, and γ-aminopropyl triethoxysilane; the urea silane coupling agent is selected from at least one of γ-urea propyl trimethoxysilane and γ-urea propyl triethoxysilane. Preferably, the coupling agent is a compound of an epoxy silane coupling agent and a urea silane coupling agent in a mass ratio of 2-4:1.

[0020] Furthermore, the coupling agent modified spherical silicon powder D50 is 0.5-0.8μm, and D100≤3μm. The coupling agent modified spherical silicon powder is prepared by a preparation method comprising the following steps: the spherical silicon powder is baked at 100-130°C for 4-6h for standby use, the silane coupling agent and the alcohol are prepared into a ball milling liquid with a mass concentration of 1-3wt%, the alcohol is selected from at least one of ethanol and isopropanol, preferably anhydrous ethanol; the silane coupling agent is an aminosilane coupling agent, specifically selected from at least one of 3-(phenylamino)propyltrimethoxysilane, NN diethylaminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane. The baked spherical silicon powder and the ball milling liquid are added to a ball mill according to a mass ratio of 10-20:80-90, wet ball milled, and dried to obtain the coupling agent modified spherical silicon powder.

[0021] Furthermore, the low molecular weight polyamide is at least one of low molecular weight polyamide 300, low molecular weight polyamide 650, and low molecular weight polyamide 651; the curing accelerator is an imidazole accelerator, specifically selected from at least one of 2-ethyl-4-methylimidazole, 4-phenylimidazole, and 4-methyl-2-phenylimidazole.

[0022] The inventors found that in the bottom filling glue, the epoxy silane coupling agent and the urea silane coupling agent are compounded as the components of the bottom filling glue, and the amino silane coupling agent is used to modify the spherical silicon powder. The three coupling agents work together to achieve the best performance.

[0023] The present invention also provides a method for preparing the bottom filling glue for the above-mentioned flip chip, comprising the following steps: adding a difunctional epoxy resin, a multifunctional epoxy resin, a polyether-modified flexible epoxy resin, a trifunctional maleimide compound, and a coupling agent into a vacuum double planetary stirring kettle, evacuating the vacuum, and stirring until uniformly dispersed; releasing the pressure, heating to 50-70°C, adding pretreated spherical silicon micropowder and then stirring evenly to obtain an epoxy resin composite, passing the above-mentioned epoxy resin composite through three rollers and grinding it three times, standing and aging it, stirring again, adding a curing agent with more than two amino groups, a low molecular weight polyamide and a curing accelerator, stirring evenly, evacuating the vacuum, and releasing the pressure to obtain the product bottom filling glue.

[0024] Compared with the prior art, the present invention has the following beneficial effects: the bottom filler provided by the present invention has high filling, high fluidity, high Tg and excellent mechanical properties. By adding the trifunctional maleimide compound of formula (I), the high temperature resistance and moisture heat resistance of the bottom filler after curing are also improved. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is further explained below with reference to specific embodiments.

[0026] Preparation Example 1

[0027] Spherical silica powder (D50 = 0.5 μm, D100 = 3 μm) was baked at 120°C for 4 h for use; 3-(phenylamino)propyltrimethoxysilane coupling agent and anhydrous ethanol were prepared as a ball milling solution in a mass ratio of 98:2; the baked spherical silica powder and the ball milling solution were added to a ball mill in a mass ratio of 10:90, and wet ball milling was performed at a ball milling speed of 500 rpm. After ball milling for 8 h, vacuum drying was performed to obtain coupling agent modified spherical silica powder.

[0028] Preparation Example 2

[0029]

[0030] Weigh 20.52g 2,3,5-triamino-1,4-naphthoquinone (0.1mol), dissolve in 100ml DMF, add to the reaction vessel, weigh 32.34g (0.4mol) maleic anhydride and dissolve in 150mL DMF was used to obtain a DMF solution of maleic anhydride; the THF solution of maleic anhydride was slowly added to the above reaction container under stirring conditions, the temperature was controlled at 10-15°C in an ice-water bath, and the addition was completed within 2 hours. After the addition was completed, the temperature was kept at 10-15°C for reaction for 2 hours; after the reaction was completed, 51.05g (0.5mol) of acetic anhydride was added to the reaction container under a nitrogen atmosphere, the temperature was raised to 120°C for dehydration reaction, the solution began to reflux, and a water separator was used for water separation. The reaction was stopped after 5 hours until no water was produced, and the reaction was naturally cooled to about 40°C. The product was poured into 10 times the volume of ice water, filtered, and the filter cake was dried and recrystallized with ethanol to obtain a crystalline product as a trifunctional maleimide compound.

[0031] Product NMR: 1 H NMR (400MHz, CDCl3) δ8.77(d,J=8.2Hz,1H),7.86(d,J=8.4Hz,6H),7.84–7.83(m,1H),7.44(d,J=8.0Hz,1H).

[0032] Example 1

[0033] 25 parts by mass of bisphenol A epoxy resin E41, 6 parts by mass of tetraglycidyl diaminodiphenylmethane, 12 parts by mass of polyethylene glycol diglycidyl ether (number average molecular weight 620), 8 parts by mass of the trifunctional maleimide compound prepared in Preparation Example 2, and 2.3 parts by mass of a silane coupling agent (γ-glycidyloxypropyl trimethoxysilane and γ-ureapropyl trimethoxysilane in a mass ratio of 3:1) were added into a vacuum double planetary stirring kettle, evacuated, and stirred until uniformly dispersed; The mixture was heated to 50°C, 100 parts by weight of the coupling agent modified spherical silicon powder prepared in Preparation Example 1 was added, and the mixture was uniformly stirred to obtain a composite. The composite was passed through three rollers and ground three times. After standing for 24 hours to mature, 6 parts by weight of curing agent 3,3'-diethyl 4,4'-diaminodiphenylmethane, 3 parts by weight of low molecular weight polyamide 651, and 0.8 parts by weight of 2-ethyl-4-methylimidazole were added again with stirring, and the mixture was uniformly stirred, vacuumed, and the pressure was released to obtain a bottom filling adhesive for flip chip packaging.

[0034] Example 2

[0035] 30 parts by mass of JER807 epoxy resin, 8 parts by mass of N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl ether, 14 parts by mass of polyethylene glycol diglycidyl ether (number average molecular weight 620), 7 parts by mass of the trifunctional maleimide compound prepared in Preparation Example 2, and 2 parts by mass of a silane coupling agent (γ-glycidyloxypropyltrimethoxysilane and γ-ureapropyltrimethoxysilane in a mass ratio of 2:1) were added into a vacuum double planetary stirring kettle, evacuated, and stirred. Stir until uniformly dispersed; release the pressure, raise the temperature to 50°C, add 100 parts by weight of the coupling agent modified spherical silicon powder obtained in Preparation Example 1, stir evenly to obtain a composite, pass the composite through three rollers and grind it three times, let it stand for 24 hours to mature, stir again, add 7 parts by weight of curing agent 3, -ethyl-4,4'-diaminodiphenylmethane, 3 parts by weight of low molecular weight polyamide 651, and 1 part by weight of 4-methyl-2-phenylimidazole, stir evenly, evacuate, and release the pressure to obtain the bottom filling glue for flip chip packaging.

[0036] Example 3

[0037] 22 parts by mass of JSR-YX4000 epoxy resin, 8 parts by mass of tetraglycidyl hydrogenated meta-phenylenediamine, 10 parts by mass of polyethylene glycol diglycidyl ether (number average molecular weight 620), 7 parts by mass of the trifunctional maleimide compound prepared in Preparation Example 2, and 2.4 parts by mass of a silane coupling agent (γ-glycidyloxypropyltrimethoxysilane and γ-ureapropyltrimethoxysilane in a mass ratio of 4:1) were added into a vacuum double planetary stirring kettle, evacuated, and stirred. Stir until uniformly dispersed; release the pressure, raise the temperature to 50°C, add 100 parts by weight of the coupling agent modified spherical silicon powder obtained in Preparation Example 1, stir evenly to obtain a composite, pass the composite through three rollers and grind it three times, let it stand for 24 hours to mature, stir again, add 5 parts by weight of curing agent diaminodiphenyl ether, 4 parts by weight of low molecular weight polyamide 650, and 1.1 parts by weight of 4-methyl-2-phenylimidazole, stir evenly, evacuate, and release the pressure to obtain the bottom filling glue for flip chip packaging.

[0038] Comparative Example 1

[0039] The other conditions were the same as those in Example 1, except that the trifunctional maleimide compound prepared in Preparation Example 2 was replaced by an equal mass of N,N-tetramethylenebismaleimide.

[0040] Comparative Example 2

[0041] The other conditions were the same as those in Example 1, except that the trifunctional maleimide compound prepared in Preparation Example 2 was replaced by an equal mass of N,N′,N″-(1,3,5-triazine-2,4,6-triyl)trimaleimide (see patent CN114133383A).

[0042] Application Examples

[0043] The bottom filling glue obtained in the above-mentioned embodiment and comparative example was subjected to the following performance test, and the results are shown in Table 1 below.

[0044] 1. Liquidity :Use two parallel glass plates with a gap of 50μm, record the time it takes for the glue to flow to the 40mm position. Preheat the heating platform at 110℃, add 1g of filling glue, and use a stopwatch to record the time required for 40mm. Observe whether there are bubbles in the glue during the flow process.

[0045] 2. Glass transition temperature Tg test :DSC method is used for testing. 10 mg of sample is placed in the equipment. The temperature is increased from 25℃ to 300℃ at a rate of 10℃ / min. The Tg data can be obtained by analyzing the obtained curve.

[0046] 3. Warpage resistance test:Prepare a test chip for evaluating the prepared bottom filling. First, on the test chip (Si size: 30mm (width) × 40mm (length) × 0.13mm (thickness), an organic resin substrate (substrate size: 180mm (width) × 240mm (length) × 0.4mm (thickness) for mounting the test chip was placed. After curing for 120 minutes at 0.6MPa and 165°C, the height difference between the center and the end of the chip was measured as the warpage value.

[0047] 4. Shear strength test : The bottom filling glue is coated on two aluminum sheets, the coating length is 12.5mm, the glue layer coating thickness is 0.2mm, the aluminum sheets are in contact, the glue layer thickness is uniform, and it is cured at 165℃ / 120min. After curing, the Al / Al shear strength is tested according to the ASTMD1002 test method.

[0048] 5. High temperature aging test : Place the cured sample at 180℃ for 24h, cool it to room temperature, and retest the shear strength. The shear strength retention rate is used to indicate the high temperature resistance of the bottom filler.

[0049] 6. Heat and humidity aging test : The cured samples were placed at 85°C, 85RH% for 300h, dried at 60°C and then retested for shear strength. The shear strength retention rate was used to indicate the moisture and heat resistance of the bottom filler.

[0050] 7. Reliability MSL level test :After the glue is filled and cured, the resistance value is tested. Then, according to the JEDEC standard J-STD-20, the MSL (moisture sensitivity level) under the following conditions is measured. The sample is taken out, wiped dry, and left to stand for 2 hours. The sample is repeatedly passed through the 260°C reflow oven 3 times to test the resistance value. Resistance value test: The resistance value of the test piece is measured, and the case showing a resistance value of 30 to 50Ω is considered qualified.

[0051] Table 1 Bottom filling glue performance test

[0052]

[0053] It can be seen from the data in Table 1 that the bottom filling glue provided by the present invention has good fluidity, high Tg, suitable mechanical strength and excellent anti-warping performance, and also has high temperature resistance and heat and humidity resistance and anti-aging properties, as well as excellent moisture resistance. This may be because the trifunctional maleimide used in the present invention has a naphthoquinone structure.

Claims

1. A bottom filler for flip chip, characterized in that: The invention comprises the following raw materials in parts by weight: 22-30 parts of a bifunctional epoxy resin, 5-8 parts of a multifunctional epoxy resin, 10-14 parts of a polyether-modified flexible epoxy resin, 7-10 parts of a trifunctional maleimide compound represented by formula (I), 4-7 parts of a curing agent containing more than two amine groups, 3-4 parts of a low molecular weight polyamide, 1-3 parts of a coupling agent, 0.5-2 parts of a curing accelerator, and 100 parts of a coupling agent-modified spherical silica powder; 2. The bottom filling glue according to claim 1, characterized in that: The trifunctional maleimide compound shown in formula (I) is obtained by reacting 2,3,5-triamino-1,4-naphthoquinone with maleic anhydride to obtain maleimide acid, which is then dehydrated; preferably, the dehydration is carried out under acid anhydride conditions, and the acid anhydride is selected from at least one of acetic anhydride and phosphoric anhydride.

3. The bottom filling glue according to claim 2, characterized in that: The molar ratio of 2,3,5-triamino-1,4-naphthoquinone, maleic anhydride and acid anhydride is 1:3.5-4:5-6.

4. The bottom filling glue according to claim 1, characterized in that: The trifunctional maleimide compound represented by formula (I) is prepared by a preparation method comprising the following steps: 2,3,5-triamino-1,4-naphthoquinone and maleic anhydride are reacted in an ice-water bath for 4-6 hours, after the reaction, anhydride is added under an inert atmosphere, the temperature is raised to 120-130° C. for dehydration reaction, after the reaction is completed, the temperature is lowered to 35-45° C., the product is poured into product ice water, filtered, the filter cake is dried, and then recrystallized to obtain a product compound of formula (I); Preferably, the inert atmosphere is nitrogen and / or argon, the volume of ice water is 10-15 times of the volume of the product, and ethanol is used for recrystallization.

5. The bottom filling glue according to claim 1, characterized in that: The bifunctional epoxy resin is selected from at least one of bisphenol A epoxy resin, bisphenol F epoxy resin and biphenyl epoxy resin, and the epoxy value is 0.3-0.

5.

6. The bottom filling glue according to claim 5, characterized in that: The bisphenol A epoxy resin is selected from at least one of E35, E41, E44, and NPEL-128E; the bisphenol F epoxy resin is selected from at least one of JER807 epoxy resin, EPIKOTE 862 epoxy resin, EPICLON830 epoxy resin, EPICLON830S epoxy resin, EPICLON835 epoxy resin, CYDF-170, GEFR170, NPEF-170, CYDF-180, YDF2001, and YDF2004; the biphenyl epoxy resin is selected from at least one of JSR's YX4000, JER-YX4000, JER-YX4000K, JER-YX4000H, JER-YL6121HA, Nippon Kayaku NC3000, Japan DIC brand HP-5000, Jiashengde BPNE3501, and Jiashengde NPTE4000.

7. The bottom filling glue according to claim 1, characterized in that: The multifunctional epoxy resin has three or more epoxy groups, and is specifically selected from at least one of triglycidyl p-aminophenol, 4,4'-diaminodiphenylmethane tetraglycidylamine epoxy resin, N,N,N',N'-tetraglycidyl-4,4'-diaminodiphenyl ether, N,N,N',N'-tetraglycidyl-1,4-diaminobenzene, N,N,N',N'-tetraglycidyl-1,3-diaminobenzene, isocyanuric acid triglycidylamine, N,N,N',N'-tetraepoxypropyl-4,4'-diaminodiphenylmethane, tetraglycidyl diaminodiphenylmethane, tetraphenylglycidyl ether methane, and tetraglycidyl hydrogenated meta-phenylenediamine; and / or The polyether-modified flexible epoxy resin is selected from at least one of polyethylene glycol diglycidyl ether and polypropylene glycol diglycidyl ether, wherein the number average molecular weight of the polyether segment is 400-600; and / or Further, the curing agent containing two or more amine groups is selected from at least one of 3,3'-diethyl 4,4'-diaminodiphenylmethane, diethyltoluenediamine, diaminodiphenylmethane, 3,-ethyl-4,4'-diaminodiphenylmethane, 2,4-diamino-3,5-dimethylthiotoluene, hendiamine, trimethylhexanediamine, m-phenylenediamine, and diaminodiphenyl ether; and / or The low molecular weight polyamide is at least one of low molecular weight polyamide 300, low molecular weight polyamide 650, and low molecular weight polyamide 651; the curing accelerator is an imidazole accelerator, specifically selected from at least one of 2-ethyl-4-methylimidazole, 4-phenylimidazole, and 4-methyl-2-phenylimidazole.

8. The bottom filling glue according to claim 1, characterized in that: The coupling agent is at least one of an epoxy silane coupling agent, an amino silane coupling agent, and a urea silane coupling agent; preferably, the coupling agent is a compound of an epoxy silane coupling agent and a urea silane coupling agent in a mass ratio of 2-4:

1. More preferably, the epoxy silane coupling agent is selected from at least one of γ-glycidyloxypropyl trimethoxysilane, γ-glycidyloxypropyl triethoxysilane, and γ-glycidyloxypropyl methyl diethoxysilane; the amino silane coupling agent is selected from at least one of 3-(phenylamino)propyl trimethoxysilane, NN diethylaminopropyl trimethoxysilane, and γ-aminopropyl triethoxysilane; the urea silane coupling agent is selected from at least one of γ-urea propyl trimethoxysilane and γ-urea propyl triethoxysilane. Preferably, the coupling agent is a compound of an epoxy silane coupling agent and a urea silane coupling agent in a mass ratio of 2-4:

1.

9. The bottom filling glue according to claim 1, characterized in that: The coupling agent modified spherical silicon micropowder has a D50 of 0.5-0.8 μm and a D100 of ≤3 μm; the coupling agent modified spherical silicon micropowder is prepared by a preparation method comprising the following steps: the spherical silicon micropowder is baked at 100-130° C. for 4-6 hours for standby use, a silane coupling agent and an alcohol are prepared into a ball milling solution with a mass concentration of 1-3wt%, the alcohol is selected from at least one of ethanol and isopropanol, preferably anhydrous ethanol; the silane coupling agent is an aminosilane coupling agent, specifically selected from at least one of 3-(phenylamino)propyltrimethoxysilane, NN diethylaminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane.

10. The method for preparing the bottom filler for flip chip according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: adding a difunctional epoxy resin, a multifunctional epoxy resin, a polyether-modified flexible epoxy resin, a trifunctional maleimide compound and a coupling agent into a vacuum double planetary stirring kettle, evacuating the kettle, and stirring the mixture until the mixture is uniformly dispersed; releasing the pressure, heating the mixture to 50-70°C, adding pretreated spherical silicon micropowder, and then stirring the mixture to obtain an epoxy resin composite; grinding the epoxy resin composite three times after passing through three rollers, standing the mixture for aging, stirring the mixture again, adding a curing agent with more than two amino groups, a low molecular weight polyamide and a curing accelerator, stirring the mixture to obtain a uniform mixture, evacuating the kettle, and releasing the pressure to obtain a bottom filling adhesive.

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