A crack-resistant and high-toughness bottom filling adhesive and its preparation method and application

Abstract

A crack-resistant and high-toughness bottom filling glue and its preparation method and application belong to the field of adhesive technology. The bottom filling glue of the present invention includes the following raw material components: epoxy resin, curing agent, filler and silane coupling agent; the curing agent is a compound modified by (E-1) toughening agent. (E-1) Toughening agent includes modified silicone oil containing reactive groups, block copolymer containing reactive groups or rubber containing reactive groups, and the reactive groups include oxirane groups, amino groups, hydroxyl groups or carboxyl groups. The preparation method and application of the bottom filling glue are also provided. The bottom filling glue of the present invention significantly improves the cracking problem in the packaging process. Toughness is improved without losing strength, and properties such as appropriate viscosity, fluidity, modulus, etc. are maintained. The reactivity of the bottom filling glue can also be regulated by adjusting the modification conditions of the curing agent to meet the diversified needs of the curing temperature and curing time of the bottom filling glue system.

Description

Technical Field

[0001] The present invention belongs to the technical field of adhesives, and specifically relates to a crack-resistant and high-toughness bottom filling adhesive, a preparation method thereof, and an application thereof. Background Art

[0002] In flip-chip packaging, bottom filler is used between the chip and the substrate to provide a stronger mechanical connection and reduce the stress on the solder joints due to the mismatch in thermal expansion coefficients between the chip and the substrate. The bottom filler is mainly composed of a cured epoxy resin filled with a large amount of silica filler. The cured epoxy resin has excellent electrical insulation, high modulus and strength, as well as good adhesion at different interfaces. It is a good bottom filler matrix resin. However, epoxy resin itself is relatively brittle. In flip-chip packaging, there are large stress strains, thermal and mechanical shocks, which can easily cause cracking problems, such as Figure 1 As shown. To address this problem, the prior art has physically introduced toughening agents into the formula, such as liquid rubber, core-shell particles, inorganic fillers, thermoplastic phases, and combinations of the above. However, such additives have limitations. For example, the use of rubber particles to improve fracture toughness usually requires a trade-off between the reduction in yield stress and the reduction in glass transition temperature. In addition, the presence of the rubber phase usually increases the viscosity of the epoxy monomer mixture, which destroys the process performance of the bottom filler. Rigid inorganic particles can increase the toughness of the epoxy resin system without affecting the glass transition temperature of the epoxy resin, but these relatively large particles also significantly increase the viscosity of the resin, reduce the elongation at break, reduce the convenience of processing, and reduce the process performance of the bottom filler. Summary of the Invention

[0003] In response to the aforementioned problems in the prior art, the present invention aims to provide a crack-resistant, high-toughness underfill, its preparation method, and application. The present invention utilizes a toughening agent-modified curing agent to prepare the underfill. This underfill significantly improves cracking during packaging while maintaining excellent process performance. Furthermore, the curing agent's modification conditions can be adjusted to regulate the underfill's reactivity, meeting diverse requirements for the underfill system's curing temperature and curing time.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions:

[0005] A crack-resistant and high-toughness bottom filling adhesive, characterized by comprising the following raw material components: epoxy resin, curing agent, filler and silane coupling agent;

[0006] Based on 100 parts by mass of the total mass of the raw materials of the bottom filling glue, the filler is 45 to 85 parts by mass, the silane coupling agent is 0.2 to 1.5 parts by mass, and the content of the curing agent is 0.6 to 1.5 equivalents relative to the epoxy equivalent of the epoxy resin;

[0007] The curing agent is a compound modified by a toughening agent (E-1).

[0008] The crack-resistant, high-toughness underfill adhesive is characterized in that the toughening agent (E-1) comprises a modified silicone oil, a block copolymer, or a rubber containing reactive groups, wherein the reactive groups include oxirane, amino, hydroxyl, or carboxyl functional groups. The toughening agent used in the modified curing agent is a block copolymer, rubber, or other toughening agent containing reactive groups that react with the functional groups of the epoxy resin or curing agent.

[0009] The crack-resistant and high-toughness bottom filling glue is characterized in that the modified silicone oil containing reactive groups includes modified silicone oil containing epoxy groups (Shin-Etsu Chemical; X-22-163), modified silicone oil containing hydroxyl groups (Shin-Etsu Chemical; KF-6000), and modified silicone oil containing carboxyl groups (Shin-Etsu Chemical; X-22-162C); the block copolymer containing reactive groups includes acryl block copolymers (Kuraray; LA2140e, LA2250, LA4285); and the rubber containing reactive groups includes carboxyl-terminated liquid nitrile rubber (CTBN) and hydroxyl-terminated liquid nitrile rubber (HTBN).

[0010] The crack-resistant and high-toughness bottom filling adhesive is characterized in that the curing agent is liquid at room temperature and is an aromatic amine curing agent or an acid anhydride curing agent.

[0011] The crack-resistant and high-toughness bottom filling glue is characterized in that the aromatic amine curing agent includes one or more of diaminodiphenylmethane (4,4'-methylenedianiline, MDA), m-phenylenediamine (MPDA), diaminodiphenyl sulfone (DDS), diethyltoluenediamine (DETDA), diaminodiphenylmethane (DDM), 3,3'-diethyl-4,4'-diaminodiphenylmethane, 4,4'-methylenebis(N-methylaniline), trimethylenebis(4-aminobenzoate), polytetrahydrofuran-bis-p-aminobenzoate, methylenebis(2-ethyl-6-methylaniline), 4,4'-methylenebis(2,6-dimethylaniline), and 4,4'-methylenebis(2,6-diethylaniline), preferably one or more of diethyltoluenediamine and 3,3'-diethyl-4,4'-diaminodiphenylmethane; and is preferred because it is easily mixed with the liquid toughening agent.

[0012] The acid anhydride curing agent includes tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, hydrogenated methyl nadic anhydride, trialkyltetrahydrophthalic anhydride, methylcyclohexanetetracarboxyl dianhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxyl dianhydride, ethylene glycol bis(anhydro) trimellitic anhydride, and the like. sanhydrotrimellitate), glycerin bis(anhydrotrimellitate) monoacetate, dodecenylsuccinic anhydride, aliphatic dibasic acid polyanhydride, chlorendic anhydride, methylbutenyltrahydrophthalic anhydride, alkylation tetrahydrophthalic anhydride, methyl HIMIC anhydride, alkenyl-substituted succinic anhydride, glutaric anhydride.

[0013] The crack-resistant and high-toughness bottom filling glue is characterized in that the epoxy resin is liquid at room temperature, the filler includes a spherical silica filler, and the particle size of the spherical silica filler is 1 to 10 μm.

[0014] The crack-resistant and high-toughness bottom filling adhesive is characterized in that the silane coupling agent contains active groups and is compatible with the epoxy system.

[0015] Any of the above-described methods for preparing a crack-resistant, high-toughness bottom filling adhesive is characterized in that it includes the following steps: uniformly mixing an epoxy resin and a silane coupling agent, stirring at 800 to 1600 rpm for 1 to 4 minutes, then adding the filler in three batches, stirring at 800 to 1600 rpm for 1 to 4 minutes after each batch is added, adding a curing agent modified with a toughening agent (E-1), stirring at 1500 to 2500 rpm for 1 to 4 minutes, and controlling the vacuum degree at -0.06 to -0.1 MPa to obtain the bottom filling adhesive.

[0016] The preparation method is characterized in that the specific method of modifying the toughening agent (E-1) is: dissolving the toughening agent (E-1) containing an ethylene oxide, amino, hydroxyl or carboxyl functional group in a curing agent at 180-210°C, stirring for 1-12 hours, and naturally cooling to room temperature.

[0017] The application of the bottom filling glue in chip packaging.

[0018] Add the toughening agent to the curing agent, dissolve it in the curing agent at 180-210℃, and stir for 1-12 hours. At a high temperature of 180-210℃, the curing agent will undergo a prepolymerization reaction with the toughening agent containing reactive groups, such as opening anhydride, primary amine to generate secondary amine, etc. Figure 2 and Figure 3 As shown). It helps to increase the reaction speed when reacting with epoxy resin, so this method can improve the curing reaction activity of the curing agent. Since stirring at high temperature can promote the dispersion of the toughening agent in the liquid curing agent on the one hand, it can also promote the pre-reaction of the reactive groups in the toughening agent and the curing agent on the other hand, which can improve the dispersion of the toughening agent in the bottom filling glue system (such as Figure 4 As shown in the figure, the toughening effect is enhanced, and the problem of uneven dispersion of powder or viscous toughening agent in the underfill resulting in increased flow time and viscosity is prevented; the viscosity of the underfill is reduced, and the rheological properties of the underfill are improved, so that the underfill material has better overall performance.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention utilizes a toughening agent-modified curing agent to prepare an underfill adhesive, which significantly improves cracking during the packaging process. While maintaining excellent processability, it effectively improves toughness without sacrificing strength, while maintaining appropriate viscosity, fluidity, modulus, and other properties. Furthermore, by adjusting the curing agent's modification conditions, the underfill adhesive's reactivity can be regulated, meeting diverse requirements for the underfill adhesive system's curing temperature and curing time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a picture of the underfill cracking in the Flip Chip;

[0022] Figure 2 It is a general formula for the pre-reaction of an amine curing agent and a carboxyl-terminated toughening agent;

[0023] Figure 3 It is a general formula for the pre-reaction of an anhydride curing agent and a hydroxyl-terminated toughening agent;

[0024] Figure 4 Comparison of the differences between traditional physical blending toughening and chemical modification toughening;

[0025] Figure 5 The cross-sectional SEM image of the product obtained in Comparative Example 1;

[0026] Figure 6 This is the bottom fill glue flow time test chart;

[0027] Figure 7 This is a cross-sectional SEM image of the product obtained in Example 3;

[0028] Figure 8 This is a typical SEM image of bottom filler cracking;

[0029] Figure 9 This is an SEM image of the chip filled with the bottom filler of the product obtained in Comparative Example 1;

[0030] Figure 10 This is an SEM image of the chip filled with the bottom filling glue of the product obtained in Example 3. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] Example 1:

[0033] Step 1: Add 15 g of carboxyl-terminated liquid nitrile rubber (CTBN) to a round-bottom flask containing 100 g of aromatic amine curing agent DETDA, and then stir and reflux at 180°C and 600 rpm for 4 h. After the reaction, allow the sample to cool naturally to room temperature to obtain a modified curing agent (B-1).

[0034] Step 2: Bisphenol F epoxy resin and silane coupling agent were mixed uniformly and stirred at 1500 rpm for 2 minutes. Then, filler was added to the above mixture in three batches, and filler (C) was stirred at 1500 rpm for 2 minutes each time. Finally, the liquid modified curing agent (B-1) obtained in step 1 was added to the mixture of (A) epoxy resin, (C) filler and (D) silane coupling agent, and stirred at 2000 rpm for 2 minutes. The vacuum degree was controlled at -0.08 MPa to obtain an underfill adhesive, wherein the filler filling amount was 60 wt%.

[0035] Comparative Example 1:

[0036] Step 1: Bisphenol F epoxy resin, carboxyl-terminated liquid nitrile rubber (CTBN), and silane coupling agent were mixed uniformly and stirred at 1500 rpm for 2 minutes. Then, filler was added to the above mixture in three batches, and each addition of filler (C) was stirred at 1500 rpm for 2 minutes. Finally, aromatic amine curing agent DETDA was added to the mixture of (A) epoxy resin, (C) filler, and (D) silane coupling agent, and stirred at 2000 rpm for 2 minutes. The vacuum was controlled at -0.08 MPa to obtain an underfill adhesive with a filler loading of 60 wt%. The cross-sectional SEM image of the product of Comparative Example 1 is shown in FIG. Figure 5 shown.

[0037] Example 2:

[0038] Step 1: Add 15 g of hydroxyl-terminated liquid nitrile rubber (HTBN) to a round-bottom flask containing 100 g of anhydride curing agent methylhexahydrophthalic anhydride, and then stir and reflux at 180°C and 600 rpm for 4 hours. After the reaction is completed, allow the sample to cool naturally to room temperature to obtain a modified curing agent (B-2).

[0039] Step 2: Bisphenol F epoxy resin and silane coupling agent were mixed uniformly and stirred at 1500 rpm for 2 minutes. Then, filler was added to the above mixture in three batches, and each addition of filler (C) was stirred at 1500 rpm for 2 minutes. Finally, the liquid modified curing agent (B-2) obtained in step 1 was added to the mixture of (A) epoxy resin, (C) filler and (D) silane coupling agent, and stirred at 2000 rpm for 2 minutes. The vacuum degree was controlled at -0.08 MPa to obtain an underfill adhesive, wherein the filler filling amount was 60 wt%.

[0040] Comparative Example 2:

[0041] Bisphenol F epoxy resin, carboxyl-terminated liquid nitrile rubber (HTBN), and a silane coupling agent were uniformly mixed and stirred at 1500 rpm for 2 minutes. Filler was then added to the mixture in three batches, with each addition of filler (C) being stirred at 1500 rpm for 2 minutes. Finally, methylhexahydrophthalic anhydride, an anhydride curing agent, was added to the mixture of (A) epoxy resin, (C) filler, and (D) silane coupling agent, and stirred at 2000 rpm for 2 minutes. The vacuum was controlled at -0.08 MPa to obtain an underfill adhesive with a filler loading of 60 wt%.

[0042]

【K 1C Determination of

[0043] The prepared liquid underfill was injected into the mold to prepare a sample 35 mm long × 7 mm wide × 3 mm thick. This sample was measured using an electronic universal testing machine (Shimadzu AGX-10kNVD). When making the sample, a crack was introduced in the middle with a blade.

[0044]

Determination of reactivity

[0045] Reactivity is the property that causes epoxy resins to cure (the property of constructing a three-dimensional network structure through crosslinking of epoxy resins and amines). Reactivity is measured using a rheometer at 165°C, measuring the initial viscosity (the state of the epoxy resin composition immediately after reaching the measurement temperature). Viscosity is then measured continuously, and the time it takes for the viscosity to reach five times the initial viscosity is determined as the reaction time.

[0046]

Viscosity measurement

[0047] Viscosity is one of the means to characterize the process performance of the bottom filling glue. The viscosity is measured using a rheometer at room temperature. The viscosity is measured as the shear rate changes, and the viscosity value when the shear rate is 501 / s is taken.

[0048]

Determination of fluidity

[0049] like Figure 6 As shown in the figure, two pieces of glass are bonded together with double-sided tape, where the tape is 50 μm thick and there is no tape in the middle 10 mm width. Then the glass plate is placed on a heating table at 110°C and kept for 2 minutes. Then, the bottom filler is dropped on one end of the glass plate. When the bottom filler enters the glass plate, the timing is started. The time from the bottom filler entering the glass plate to the time it flows to 30 mm is recorded as the bottom filler flow time.

[0050] The above performance measurements were performed on Examples 1 and 2 and Comparative Examples 1 and 2, and the results are shown in Table 1 below.

[0051] Table 1 Performance test results of Examples 1-2 and Comparative Examples 1-2

[0052]

[0053]

[0054] Example 3:

[0055] Step 1: Add 15 g of carboxyl-terminated liquid nitrile rubber (CTBN) to a round-bottom flask containing 100 g of an aromatic amine curing agent, DETDA, and then stir and reflux at 190°C and 600 rpm for 4 h. After the reaction, allow the sample to cool naturally to room temperature to obtain a modified curing agent (B-3).

[0056] Step 2: Bisphenol F epoxy resin and silane coupling agent were mixed uniformly and stirred at 1500 rpm for 2 minutes. Then, filler was added to the above mixture in three batches, and each addition of filler (C) was stirred at 1500 rpm for 2 minutes. Finally, the liquid modified curing agent (B-3) obtained in step 1 was added to the mixture of (A) epoxy resin, (C) filler and (D) silane coupling agent, and stirred at 2000 rpm for 2 minutes. The vacuum degree was controlled at -0.08 MPa to obtain an underfill adhesive with a filler filling amount of 60 wt%. The cross-sectional SEM image of the obtained product is shown below. Figure 7 shown.

[0057] Example 4:

[0058] Step 1: Add 15 g of carboxyl-terminated liquid nitrile rubber (CTBN) to a round-bottom flask containing 100 g of aromatic amine curing agent DETDA, and then stir and reflux at 200°C and 600 rpm for 4 h. After the reaction, allow the sample to cool naturally to room temperature to obtain a modified curing agent (B-4).

[0059] Step 2: Bisphenol F epoxy resin and silane coupling agent were uniformly mixed and stirred at 1500 rpm for 2 minutes. Then, filler was added to the above mixture in three batches, and filler (C) was stirred at 1500 rpm for 2 minutes each time. Finally, the liquid modified curing agent (B-4) obtained in step 1 was added to the mixture of (A) epoxy resin, (C) filler and (D) silane coupling agent, and stirred at 2000 rpm for 2 minutes. The vacuum degree was controlled at -0.08 MPa to obtain an underfill adhesive, wherein the filler filling amount was 60 wt%.

[0060] Example 5:

[0061] Step 1: Add 15 g of carboxyl-terminated liquid nitrile rubber (CTBN) to a round-bottom flask containing 100 g of aromatic amine curing agent DETDA, and then stir and reflux at 210°C and 600 rpm for 4 h. After the reaction, allow the sample to cool naturally to room temperature to obtain a modified curing agent (B-5).

[0062] Step 2: Bisphenol F epoxy resin and silane coupling agent were mixed uniformly and stirred at 1500 rpm for 2 minutes. Then, filler was added to the above mixture in three batches, and filler (C) was stirred at 1500 rpm for 2 minutes each time. Finally, the liquid modified curing agent (B-5) obtained in step 1 was added to the mixture of (A) epoxy resin, (C) filler and (D) silane coupling agent, and stirred at 2000 rpm for 2 minutes. The vacuum degree was controlled at -0.08 MPa to obtain an underfill adhesive, wherein the filler filling amount was 60 wt%.

[0063] Performance tests were performed on Example 1, Examples 3-5, and Comparative Example 1, and the results are shown in Table 2 below.

[0064] Table 2 Performance test results of Example 1, Examples 3-5 and Comparative Example 1

[0065]

[0066] Combined with Tables 1 and 2 above, it can be explained that compared with the bottom filling glue in which the traditional toughening agent is added in a blending manner, such as Figure 8 The following is a typical SEM picture of bottom filler cracking. The high-toughness bottom filler provided by the present invention has advantages in performance mainly in the following aspects: The SEM picture of the bottom filler-filled chip of the product obtained in Comparative Example 1 is as follows: Figure 9 As shown, the SEM of the bottom filling glue filled chip of the product obtained in Example 3 is as follows Figure 10 shown.

[0067] 1. Dispersibility: Traditional blended toughening agents are usually difficult to disperse evenly in the bottom filling glue due to the difference in polarity. The bottom filling glue containing the toughening agent modified curing agent provided by the present invention can assist the toughening agent to be evenly dispersed in the curing agent by high-temperature stirring, thereby achieving uniform dispersion of the toughening agent in the bottom filling glue.

[0068] 2. Mechanical properties: Traditionally, the toughening agent is blended in the bottom filling glue. The bottom filling glue provided by the present invention, which contains a toughening agent-modified curing agent, can improve the dispersion of the toughening agent in the bottom filling glue and the interfacial interaction with the epoxy resin by controlling the curing agent modification conditions, thereby achieving low stress and improved toughness of the bottom filling glue.

[0069] 3. Reactivity: It can be seen that compared with traditional blended toughening agents in bottom filling glue, the anti-cracking high-toughness bottom filling glue provided by the present invention has higher reactivity, and with the increase of modification temperature, the reactivity gradually increases. This modified curing agent with adjustable reactivity provides a wider operating process range for the bottom filling glue.

[0070] 4. Fluidity and viscosity: Compared with the traditional blended toughening agent in the bottom filling glue, the bottom filling glue provided by the present invention containing a toughening agent modified curing agent has a faster flow rate and lower viscosity. This improvement in fluidity is conducive to improving the generation of defects such as voids in the bottom filling glue when filling the chip.

[0071] 5. Anti-cracking: Compared with the traditional blended toughening agent in the bottom filling glue, the anti-cracking high-toughness bottom filling glue provided by the present invention can effectively improve the cracking problem in the chip packaging process.

[0072] The present invention has been experimentally verified with good results. The bottom filling glue prepared by this method can effectively prevent the bottom filling glue from cracking during the chip packaging process, and the bottom filling glue has high reactivity and good rheological properties.

Claims

1. A crack-resistant and high-toughness bottom filling glue, characterized by The invention comprises the following raw material components: epoxy resin, curing agent, filler and silane coupling agent; Based on 100 parts by mass of the total mass of the raw materials of the bottom filling glue, the filler is 45 to 85 parts by mass, the silane coupling agent is 0.2 to 1.5 parts by mass, and the content of the curing agent is 0.6 to 1.5 equivalents relative to the epoxy equivalent of the epoxy resin; The curing agent is a compound modified by a toughening agent (E-1); The specific method of modifying the toughening agent (E-1) is as follows: dissolving the toughening agent (E-1) containing an oxirane group, an amino group, a hydroxyl group or a carboxyl group functional group in a curing agent at 180 to 210° C., stirring for 1 to 12 hours, and naturally cooling to room temperature; The (E-1) toughening agent includes modified silicone oil containing reactive groups, block copolymer containing reactive groups or rubber containing reactive groups, and the reactive groups include oxirane, amino, hydroxyl or carboxyl functional groups.

2. The anti-cracking and high-toughness bottom filling adhesive according to claim 1, characterized in that The block copolymer containing reactive groups includes an acryl block copolymer, and the rubber containing reactive groups includes a carboxyl-terminated liquid nitrile rubber and a hydroxyl-terminated liquid nitrile rubber.

3. The anti-cracking and high-toughness bottom filling adhesive according to claim 1, characterized in that The curing agent is liquid at room temperature and is an aromatic amine curing agent or an acid anhydride curing agent.

4. The anti-cracking and high-toughness bottom filling adhesive according to claim 3, characterized in that The aromatic amine curing agent includes one or more of diaminodiphenylmethane, m-phenylenediamine, diaminodiphenyl sulfone, diethyltoluenediamine, 3,3'-diethyl-4,4'-diaminodiphenylmethane, 4,4'-methylenebis(N-methylaniline), trimethylenebis(4-aminobenzoate), polytetrahydrofuran-bis-p-aminobenzoate, methylenebis(2-ethyl-6-methylaniline), 4,4'-methylenebis(2,6-dimethylaniline), and 4,4'-methylenebis(2,6-diethylaniline); The anhydride curing agent includes tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, methylcyclohexanetetracarboxylic dianhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenonetetracarboxylic dianhydride, ethylene glycol dianhydrotrimellitate, glycerol bis(anhydrotrimellitate) monoacetate, dodecenylsuccinic anhydride, aliphatic dibasic acid polyanhydride, chlorendic anhydride, methylbutenyltetrahydrophthalic anhydride, alkylated tetrahydrophthalic anhydride, methylHIMIC anhydride, alkenyl substituted succinic anhydride, and glutaric anhydride.

5. The anti-cracking and high-toughness bottom filling adhesive according to claim 4, characterized in that The aromatic amine curing agent includes one or more of diethyltoluenediamine and 3,3'-diethyl-4,4'-diaminodiphenylmethane.

6. The anti-cracking and high-toughness bottom filling adhesive according to claim 1, characterized in that The epoxy resin is liquid at room temperature, and the filler comprises a spherical silica filler having a particle size of 1 to 10 μm.

7. The anti-cracking and high-toughness bottom filling adhesive according to claim 1, characterized in that The silane coupling agent contains active groups and is compatible with the epoxy system.

8. A method for preparing a crack-resistant and high-toughness bottom filling adhesive according to any one of claims 1 to 7, characterized in that The following steps are involved: The epoxy resin and silane coupling agent are mixed evenly, stirred at 800-1600 rpm for 1-4 minutes, and then the filler is added in three batches. After each batch is added, the mixture is stirred at 800-1600 rpm for 1-4 minutes. The curing agent modified with the toughening agent (E-1) is added and stirred at 1500-2500 rpm for 1-4 minutes. The vacuum degree is controlled at -0.06-0.1 MPa to obtain the bottom filling glue.

9. Use of the bottom filling adhesive according to any one of claims 1 to 7 in chip packaging.

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