Low-dielectric chip mounting adhesive film composition and adhesive film

Abstract

The invention provides a low-dielectric chip mounting adhesive film composition and an adhesive film, the low-dielectric chip mounting adhesive film composition is prepared from the following raw materials in parts by weight: 100 parts of epoxy resin, 10-30 parts of a toughening agent, 40-50 parts of a curing agent, 0.5-2 parts of an accelerant and 100-250 parts of inorganic filler, and the curing agent is prepared by compounding an aryl bifunctional primary amine curing agent and a trifunctional phenol curing agent according to the mass ratio of 3: (10-12). The three-functionality phenol curing agent is synthesized by taking a benzenetricarboxaldehyde derivative and an aminophenol derivative as raw materials through a Schiff base reaction, a branched chain of the three-functionality phenol curing agent contains an aromatic ring structure and a C = N bond, the three-functionality phenol curing agent is a star-shaped three-arm compound, namely, the three-functionality phenol curing agent, and due to the fact that the aromatic ring structure is large in size, the C = N bond is high in rigidity, and the curing agent is small in displacement space, the curing agent is not prone to falling off. The adhesive film composition has high resistance to polar groups in molecules and can better hinder polarization orientation, so that the molecular polarity of the cured adhesive film composition is reduced, and the dielectric constant and the dielectric loss are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor packaging, and in particular relates to a low-dielectric chip mounting adhesive film composition and an adhesive film. Background Art

[0002] In traditional semiconductor packaging technology, glue, such as epoxy resin, silicone, etc., is often used in chip mounting. However, as the package size becomes smaller and smaller, and the number of chips in a single package increases, glue can no longer meet the process requirements. Mounting film is a thin film composite material that is attached to the back of the chip, thereby eliminating the glue painting and dispensing processes, greatly shortening the chip mounting process time, and thus improving the chip mounting process capacity.

[0003] Epoxy resin has the advantages of easy processing, chemical corrosion resistance, high mass fraction filling of fillers, and intrinsic insulation of resin. The mounting film with epoxy resin as the film base resin has a wide range of applications in the field of semiconductor packaging, such as the halogen-free epoxy resin flame retardant adhesive and its film disclosed in patent CN101602925B, including: 100 parts of epoxy resin, 35-50 parts of carboxyl-containing nitrile rubber, 8-15 parts of curing agent, and 0.5-2.0 parts of curing accelerator. Patent CN114292615B discloses a composition, film and chip packaging structure, wherein the composition includes epoxy resin, surfactant, curing agent and filler, and the surfactant is selected from modified hexafluoropropylene compounds. The surfactant in the composition is a modified hexafluoropropylene compound.

[0004] From the above technology, it can be seen that the mounting film with epoxy resin as the film base resin can form a good packaging layer for the chip with mechanical fixation, electrical isolation, impact resistance, and thermal protection characteristics. However, with the development of the microelectronics industry and the advent of the 5G era, the circuit integration is getting higher and higher, and a series of problems such as signal transmission delay and crosstalk, dielectric loss leading to increased power consumption, and noise interference have emerged. The dielectric constant of the mounting film with epoxy resin as the film base resin can no longer meet the requirements of the rapidly developing microelectronics industry. It is necessary to further improve the film with epoxy resin as the base resin to reduce the overall dielectric constant of the film and further reduce the signal hysteresis time. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a low dielectric chip mounting adhesive film composition and adhesive film. A branched star-shaped three-arm compound containing an aromatic ring structure and a C=N bond, a trifunctional phenol curing agent, is synthesized by Schiff base reaction using benzene trimeraldehyde derivatives and aminophenol derivatives as raw materials. Due to the large volume of the aromatic ring structure and the strong rigidity of the C=N bond, the displacement space of this curing agent is small, the ability to hinder polar groups in the molecule is large, and the polarization orientation can be better hindered, so that the molecular polarity of the adhesive film composition after curing is reduced, and the dielectric constant and dielectric loss are reduced.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A low dielectric chip mounting adhesive film composition comprises the following raw materials in parts by weight: 100 parts of epoxy resin, 10-30 parts of toughening agent, 40-50 parts of curing agent, 0.5-2 parts of accelerator, and 100-250 parts of inorganic filler. The curing agent is compounded by an aromatic difunctional primary amine curing agent and a trifunctional phenol curing agent in a mass ratio of 3:10-12. The trifunctional phenol curing agent has a structural formula as shown in Formula I below:

[0008] Formula I:

[0009] Among them, R1 is independently R2, R3, and R4 are independently - (chemical bond) or C1-C3 alkylene.

[0010] The aromatic difunctional primary amine curing agent is selected from one or a combination of two or more of 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, metaphenylenediamine, 3,4'-diaminodiphenylmethane, and metaphenylenediamine, preferably 4,4'-diaminodiphenylmethane. The compound of a difunctional primary amine curing agent and a trifunctional phenol curing agent is used as a curing agent. By increasing the volume and rigidity of the curing agent, the dielectric constant of the film can be significantly reduced, but the compounding ratio needs to be appropriate: if the compounding ratio is too small, internal stress is easily generated inside the film, which is easily released in a hot and humid environment, resulting in a decrease in the mechanical properties of the cured product of the film composition; if the compounding ratio is too large, it is not enough to form a group steric hindrance to limit the movement of the molecular chain, and the effect of reducing the dielectric constant and dielectric loss of the epoxy resin is not obvious.

[0011] The trifunctional phenol curing agent is prepared by Schiff base reaction between the aldehyde group on the benzene trimeraldehyde derivative and the amino group on the aminophenol derivative, and the molar ratio of the aldehyde group to the amino group is 0.9:1.12-1.18.

[0012] The benzene trimesic acid derivative is selected from one or a combination of two or more of trimesic acid, benzene-1,2,4-tricarbaldehyde, 3,4',5-trialdehyde-1,1-biphenyl, [1,1'-biphenyl]-3,3',5-tricarbaldehyde, [1,1':3',1"-terphenyl]-4,4",5'-tricarbaldehyde, preferably [1,1':3',1"-terphenyl]-4,4",5'-tricarbaldehyde.

[0013] The aminophenol derivative is selected from p-aminophenol, m-aminophenol, o-aminophenol, 4-(aminomethyl)phenol, 3-(aminomethyl)phenol, 2-(aminomethyl)phenol, 2-(2-aminoethyl)phenol, 3-(2-aminoethyl)phenol, 4-hydroxyphenethylamine, 4-(3-aminopropyl)phenol, 2-(3-aminopropyl)phenol, 3-(3-amino-propyl)-phenol, or a combination of two or more thereof, preferably p-aminophenol.

[0014] Specifically, the trifunctional phenol curing agent is prepared by a method comprising the following steps:

[0015] Under an inert gas atmosphere, benzene trimeraldehyde derivatives and aminophenol derivatives are dissolved in an organic solvent, glacial acetic acid catalyst is added, the temperature is raised to reflux state for reaction, after the reaction is completed, the mixture is naturally cooled to room temperature, the solvent is removed by vacuum distillation, and the mixture is washed and recrystallized to obtain a trifunctional phenol curing agent.

[0016] The organic solvent comprises one or a combination of DMSO and DMF. The washing is performed 1-3 times with at least one of acetone, methyl ethyl ketone, n-butanol and tetrahydrofuran. The recrystallization is performed in ethanol. The amount of the catalyst is 5-8wt% of the sum of the mass of the benzene trimeraldehyde derivative and the aminophenol derivative. The reaction time is 3-5h.

[0017] The epoxy resin is a mixed epoxy resin of liquid bisphenol epoxy resin and phenol biphenyl epoxy resin in a mass ratio of 1:3-4.

[0018] The epoxy equivalent of the liquid bisphenol epoxy resin is 170-250 g / eq, and the epoxy equivalent of the phenol biphenyl epoxy resin is 200-300 g / eq.

[0019] The toughening agent is selected from one or a combination of two or more of nitrile rubber, nitrile rubber derivatives, natural rubber, and ethylene propylene rubber. Preferably, the toughening agent is a nitrile rubber derivative, and more preferably, the toughening agent is epoxy-modified liquid nitrile rubber with an epoxy equivalent of 1200-1800 g / eq.

[0020] The curing accelerator is selected from one or a combination of two of organic amines and imidazole compounds; the organic amine is selected from one or a combination of two or more of triethylamine, benzyldimethylamine and pyridine; the imidazole compound is selected from one or a combination of two or more of imidazole, 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-hydroxymethylimidazole.

[0021] The inorganic filler has an average particle size of 0.1-3 μm, preferably 0.5-1.5, and is selected from one or a combination of two or more of silicon dioxide, calcium carbonate, aluminum hydroxide, magnesium hydroxide, aluminum oxide, aluminum nitride, silicon nitride, and boron nitride, preferably silicon dioxide.

[0022] The low dielectric die attach adhesive film composition further comprises an organic solvent selected from one or a combination of two or more of toluene, xylene, butanone, acetone, methyl ethyl ketone, cyclohexanone, ethyl acetate, and N,N-dimethylformamide.

[0023] The mass fraction of the organic solvent in the low dielectric die attach adhesive film composition is 40-60 wt %.

[0024] A glue film is obtained by coating the low dielectric chip mounting glue film composition on a release film.

[0025] Specifically, the preparation method of the adhesive film comprises the following steps: uniformly mixing epoxy resin, toughening agent, curing agent, curing accelerator, inorganic filler and organic solvent, coating the mixture on a release film, and drying the mixture to obtain the adhesive film.

[0026] The release film has a thickness of 20-60 μm and is selected from one or a combination of two or more of PET film, polyethylene film, polypropylene film, and polyvinyl chloride film; the thickness of the low dielectric chip mounting film composition after drying is 5-50 μm, preferably 10-30 μm.

[0027] The drying temperature is 80-130° C. and the drying time is 3-15 minutes.

[0028] The curing conditions of the adhesive film are: curing at 150-170° C. for 1-3 hours.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention uses benzene trimeraldehyde derivatives and aminophenol derivatives as raw materials to synthesize a branched chain star-shaped three-arm compound containing an aromatic ring structure and a C=N bond through a Schiff base reaction, which is a trifunctional phenol curing agent. Since the aromatic ring structure is relatively large in volume and the C=N bond is highly rigid, the displacement space of the curing agent is relatively small, and the hindering ability to the polar groups in the molecule is relatively large, which can better hinder the polarization orientation, reduce the molecular polarity of the adhesive film composition after curing, and reduce the dielectric constant and dielectric loss. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with specific embodiments, but is not limited to the contents of the specification. Unless otherwise specified, the "parts" described in the embodiments of the present invention are all parts by weight. The reagents used are all commercially available reagents in the art.

[0032] Epoxy-modified nitrile liquid rubber was purchased from Huntsman Company, brand RK84L is an epoxy-modified nitrile liquid rubber with a nitrile rubber content of 32% and an epoxy equivalent of 1250-1500 g / eq.

[0033] The PET release film was purchased from Zhejiang Jiemei Electronic Technology Co., Ltd. with a thickness of 50 μm.

[0034] Liquid bisphenol A epoxy resin was purchased from Dow Chemical with a brand name of DER 331-EL and an epoxy equivalent weight of 190 g / eq.

[0035] Phenol biphenyl type epoxy resin was purchased from Shandong Shengquan Chemical Co., Ltd. with a brand name of SQXN-324 and an epoxy equivalent of 300 g / eq.

[0036] Spherical silica was purchased from Yaduma Co., Ltd., Japan, brand SO-C4, with a specific surface area of ​​3-6m 2 / g, and the average particle size is 0.9μm.

[0037] Example 1

[0038] 1) Under nitrogen atmosphere, 0.3 mol [1,1':3',1"-terphenyl]-4,4",5'-triformaldehyde and 1.18 mol p-aminophenol were dissolved in 500 mL DMF, 12 g glacial acetic acid catalyst was added, the temperature was raised to reflux and reacted for 5 h, after the reaction was completed, the mixture was naturally cooled to room temperature, the mixed solvent was removed by vacuum distillation, the solid was washed with acetone for 3 times, and the trifunctional phenol curing agent was obtained by recrystallization in ethanol. The reaction formula of this step is shown below;

[0039]

[0040] 2) 20g liquid bisphenol A epoxy resin DER 331-EL, 80g Quanhua SQXN-324, 30g nitrile rubber derivative RK84L, 50g of a curing agent prepared by compounding 4,4'-diaminodiphenylmethane and the trifunctional phenol curing agent obtained in step 1) at a mass ratio of 3:10, 1g of 2-methylimidazole, 150g of spherical silica SQ-5, and 235g of acetone were uniformly mixed to obtain a low dielectric chip mounting film composition. The film composition was coated on a PET release film and dried at 80°C for 10 minutes. The dried film composition had a thickness of 25 μm to obtain a film.

[0041] Example 2

[0042] The rest is the same as Example 1, except that in step 2), the mass ratio of 4,4'-diaminodiphenylmethane to the trifunctional phenol curing agent is 3:12.

[0043] Example 3

[0044] The rest is the same as Example 1, except that the amount of p-aminophenol used in step 1) is 1.12 mol.

[0045] Example 4

[0046] The rest is the same as Example 1, except that an equimolar amount of 4-(aminomethyl)phenol is used to replace aminophenol.

[0047] Example 5

[0048] The rest is the same as Example 1, except that an equimolar amount of trimesic acid aldehyde is used to replace [1,1':3',1"-terphenyl]-4,4",5'-tricarbaldehyde.

[0049] Example 6

[0050] The rest is the same as Example 1, except that the amount of curing agent used is 40g.

[0051] Example 7

[0052] The rest is the same as Example 1, except that in step 2) 25g of liquid bisphenol A epoxy resin DER 331-EL, 75g of Quanhua SQXN-324, and 10g of nitrile rubber derivative RK84L, 50g of a curing agent prepared by compounding 4,4'-diaminodiphenylmethane and the trifunctional phenol curing agent obtained in step 1) at a mass ratio of 3:12, 1g of 2-methylimidazole, 150g of spherical silica SQ-5, and 235g of acetone were uniformly mixed to obtain a low dielectric chip mounting film composition. The film composition was coated on a PET release film and dried at 80°C for 10 minutes. The dried film composition had a thickness of 25 μm to obtain a film.

[0053] Comparative Example 1

[0054] The rest is the same as Example 1, except that the curing agent in step 2) is compounded by mixing 4,4'-diaminodiphenylmethane and the trifunctional phenol curing agent obtained in step 1) at a mass ratio of 1:12.

[0055] Comparative Example 2

[0056] The rest is the same as Example 1, except that the curing agent in step 2) is compounded by mixing 4,4'-diaminodiphenylmethane and the trifunctional phenol curing agent obtained in step 1) at a mass ratio of 5:12.

[0057] The films prepared in the above examples and comparative examples were cured at 170°C for 2 hours and then subjected to the following performance tests:

[0058] Shear strength: Cut a 25μm thick wafer into 50mm×50mm sizes, then stick the film to the mirror surface of the wafer at 70°C, remove the PET release film, and bond one side of the wafer film to the copper substrate at 120°C, 0.2kg, 1s. Finally, heat and cure the sample at 170°C for 2h. Use the fully automatic push-pull tester WBE-9088B produced by Dongguan Weibang Instrument Equipment Co., Ltd. to test the shear strength at a speed of 0.2mm / s.

[0059] Hygrothermal aging: Aging for 168h at 85℃ and 85%RH, re-measure the above shear strength and calculate the shear strength loss rate.

[0060] Dielectric properties: including the test of dielectric constant (Dk) and dielectric loss tangent (Df). The specimens were cut into square pieces of 50mm×50mm×25μm and tested at room temperature using Agilent's E4991A RF impedance tester after absolute drying. The test frequency was 1GHz.

[0061] Table 1 Test results

[0062] project Dk Df Shear strength MPa Shear strength loss rate after wet heat aging % Example 1 3.0 0.020 7.2 1.5 Example 2 2.8 0.026 7.4 1.8 Example 3 3.0 0.021 7.1 1.5 Example 4 3.1 0.029 7.0 2.0 Example 5 3.3 0.027 6.6 2.9 Example 6 3.4 0.030 6.4 2.1 Example 7 3.2 0.028 6.9 2.2 Comparative Example 1 2.8 0.014 7.5 8.7 Comparative Example 2 3.7 0.130 6.1 3.8

[0063] It can be seen from Table 1 that the mounting adhesive film prepared by the present invention has a lower dielectric constant, dielectric loss, and higher shear strength, and can better protect the chip from damage by external mechanical stress, thereby improving the reliability and service life of the chip.

[0064] The above detailed description is a specific description of one feasible embodiment of the present invention. The embodiment is not intended to limit the patent scope of the present invention. Any equivalent implementation or modification that does not deviate from the present invention should be included in the scope of the technical solution of the present invention.

Claims

1. A low dielectric die attach film composition, characterized in that: The invention comprises the following raw materials in parts by weight: 100 parts of epoxy resin, 10-30 parts of toughening agent, 40-50 parts of curing agent, 0.5-2 parts of accelerator, and 100-250 parts of inorganic filler. The curing agent is compounded by an aromatic difunctional primary amine curing agent and a trifunctional phenol curing agent in a mass ratio of 3:10-12. The structural formula of the trifunctional phenol curing agent is shown in the following formula I: Formula I: Among them, R1 is independently R2, R3, and R4 are independently - (chemical bond) or C1-C3 alkylene.

2. The low dielectric die attach film composition according to claim 1, characterized in that: The aromatic difunctional primary amine curing agent is selected from one or a combination of two or more of 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, meta-phenylenediamine, 3,4'-diaminodiphenylmethane, and meta-phenylenediamine, preferably 4,4'-diaminodiphenylmethane.

3. The low dielectric die attach film composition according to claim 1, characterized in that: The trifunctional phenol curing agent is prepared by Schiff base reaction between the aldehyde group on the benzene trimeraldehyde derivative and the amino group on the aminophenol derivative, and the molar ratio of the aldehyde group to the amino group is 0.9:1.12-1.

18.

4. The low dielectric die attach adhesive film composition according to claim 3, characterized in that: The benzene trimesic acid derivative is selected from one or a combination of two or more of trimesic acid, benzene-1,2,4-tricarbaldehyde, 3,4',5-trialdehyde-1,1-biphenyl, [1,1'-biphenyl]-3,3',5-tricarbaldehyde, [1,1':3',1"-terphenyl]-4,4",5'-tricarbaldehyde, preferably [1,1':3',1"-terphenyl]-4,4",5'-tricarbaldehyde; the aminophenol derivative The organism is selected from p-aminophenol, m-aminophenol, o-aminophenol, 4-(aminomethyl)phenol, 3-(aminomethyl)phenol, 2-(aminomethyl)phenol, 2-(2-aminoethyl)phenol, 3-(2-aminoethyl)phenol, 4-hydroxyphenethylamine, 4-(3-aminopropyl)phenol, 2-(3-aminopropyl)phenol, 3-(3-amino-propyl)-phenol, one or a combination of two or more thereof, preferably p-aminophenol.

5. The low dielectric die attach adhesive film composition according to claim 3, characterized in that: The trifunctional phenol curing agent is prepared by a method comprising the following steps: Under an inert gas atmosphere, benzene trimeraldehyde derivatives and aminophenol derivatives are dissolved in an organic solvent, glacial acetic acid catalyst is added, the temperature is raised to reflux state for reaction, after the reaction is completed, the mixture is naturally cooled to room temperature, the solvent is removed by vacuum distillation, and the mixture is washed and recrystallized to obtain a trifunctional phenol curing agent.

6. The low dielectric die attach adhesive film composition according to claim 5, characterized in that: The organic solvent comprises one or a combination of DMSO and DMF; the recrystallization is carried out in ethanol; the amount of the glacial acetic acid catalyst is 5-8wt% of the total mass of the benzene trimeraldehyde derivative and the aminophenol derivative; and the reaction time is 3-5h.

7. The low dielectric die attach adhesive film composition according to claim 1, characterized in that: The epoxy resin is a mixed epoxy resin of liquid bisphenol epoxy resin and phenol biphenyl epoxy resin in a mass ratio of 1:3-4; the epoxy equivalent of the liquid bisphenol epoxy resin is 170-250 g / eq, and the epoxy equivalent of the phenol biphenyl epoxy resin is 200-300 g / eq.

8. The low dielectric die attach film composition according to claim 1, characterized in that: The low dielectric die attach adhesive film composition further comprises an organic solvent, which is selected from one or a combination of two or more of toluene, xylene, butanone, acetone, methyl ethyl ketone, cyclohexanone, ethyl acetate, and N,N-dimethylformamide; the mass fraction of the organic solvent in the low dielectric die attach adhesive film composition is 40-60wt%.

9. An adhesive film, obtained by coating the low dielectric die attach adhesive film composition according to any one of claims 1 to 8 on a release film.

10. The adhesive film according to claim 9, characterized in that: The preparation method of the adhesive film comprises the following steps: epoxy resin, toughening agent, curing agent, curing accelerator, inorganic filler and organic solvent are uniformly mixed, coated on a release film, and dried to obtain the adhesive film.

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