High-temperature-resistant low-dielectric composite film as well as preparation method and application thereof

Abstract

The invention relates to the technical field of dielectric materials, in particular to a high-temperature-resistant low-dielectric composite film and a preparation method and application thereof. The high-temperature-resistant low-dielectric composite thin film comprises a TFB-BD-COF thin film and a doped cycloolefin copolymer COC, wherein the TFB-BD-COF thin film is prepared from benzenetricarboxaldehyde and 4, 4-diaminobiphenyl through an interfacial polymerization method. According to the invention, the ultralow dielectric constant, small dielectric loss, good thermal stability and good mechanical properties are realized through synergistic compounding of the two components.

Description

Technical Field

[0001] The present application relates to the technical field of dielectric materials, and more specifically, to a high-temperature resistant low-dielectric composite film and a preparation method and application thereof. Background Art

[0002] Low-k dielectric polymer materials serve as core materials for antennas, interlayer dielectrics, communication cables, and various telecommunications equipment. Their dielectric constant (k) directly determines the functions and performance of dielectric materials in electrical and electronic equipment. A low dielectric constant helps minimize parasitic resistance-capacitance delay, crosstalk noise, and power consumption. Therefore, current research and development is based on reducing the dielectric constant of polymers.

[0003] A common method to further reduce the dielectric constant of polymers in related technologies is to add inorganic materials containing high voids, thereby increasing the porosity of the composite material and reducing the dielectric constant. However, due to the poor compatibility between polymers and inorganic materials, agglomeration often occurs, resulting in a deterioration of dielectric properties. Therefore, covalent organic framework (COF) films have become a new ideal material. Covalent organic framework (COF) films achieve lower dielectric constant, dielectric loss, and higher thermal stability by combining the processability of polymers with the porosity and atomic precision of crystalline porous materials. These properties have long been pursued by the electronics community, but are difficult to achieve due to many limitations in process and material selection. Therefore, a high-temperature resistant, low-dielectric composite film, its preparation method, and application are provided. Summary of the Invention

[0004] In order to solve the above-mentioned technical problems, the present application provides a high-temperature resistant low-dielectric composite film and its preparation method and application. First, a TFB-BD-COF film is prepared by interfacial polymerization. The film exhibits an ultra-low dielectric constant, small dielectric loss and good thermal stability. The mechanical properties are further enhanced by mixing COC, thereby effectively meeting the application in dielectric products.

[0005] In the first aspect, the present application provides a high temperature resistant low dielectric composite film, the scheme is as follows: A high-temperature resistant low-dielectric composite film comprises a TFB-BD-COF film prepared from trimesaldehyde and 4,4-diaminobiphenyl through an interfacial polymerization method.

[0006] Preferably, the TFB-BD-COF has a hexagonal phase structure; The XRD spectrum has characteristic peaks at 2θ=3.58°, 6.19°, and 7.15°, and the porosity is ≥60%.

[0007] Preferably, it also includes cycloolefin copolymer-COC, wherein the volume resistivity of the COC is greater than 1.0*1016 , dissipation factor (7.0*10 (-5) , 1.00 GHz), tracking index>600, transmittance 92%.

[0008] Preferably, the weight ratio of the TFB-BD-COF film to the COC particles is 1:(10-50).

[0009] By adopting the above technical solution, the TFB-BD-COF film prepared by interfacial polymerization of trimesaldehyde and 4,4-diaminobiphenyl, after being doped with cyclic olefin copolymer COC, synergistically achieved an ultra-low dielectric constant, low dielectric loss, good thermal stability and mechanical properties. Combined with the corresponding test data and comparative experiments, the reasons may be as follows: 1) Multi-scale pore structure: TFB-BD-COF itself has a microporous structure, while COC as a continuous phase may form mesoporous or amorphous regions. This multi-scale pore structure further reduces the overall density of the material, thereby reducing the dielectric constant; 2) Improved thermal stability: TFB-BD-COF itself has a high thermal decomposition temperature, and COC also has good thermal stability (usually with a heat deformation temperature above 100°C). The combination of the two will not significantly reduce thermal performance, but may improve overall thermal stability due to enhanced structural stability. 3) Balance of dielectric properties: The high porosity of COF reduces the dielectric constant, but may lead to a decrease in mechanical properties; the introduction of COC makes up for this defect, improving mechanical strength and processing performance while maintaining a low dielectric constant, achieving synergistic optimization of performance.

[0010] In a second aspect, the present application provides a method for preparing a high-temperature resistant low-dielectric composite film, which adopts the following technical solution: A method for preparing a high-temperature resistant low-dielectric composite film, comprising the following steps: S1. Preparation of TFB-BD-COF film: Dissolve TFB and BD in dichloromethane separately, stir and mix, then add 3M acetic acid solution, let stand for 4-5 days to form a film, wash and dry to obtain the film; S2. Prepare COC solution: dissolve COC granules in xylene, heat and stir until dissolved; S3, blending film formation: grind the TFB-BD-COF film obtained in S1 and disperse it in DMB. After mixing evenly, mix it with the COC solution obtained in S2 according to the corresponding weight ratio. After mixing evenly, apply and vacuum dry to obtain a composite film.

[0011] Preferably, the specific process for preparing the TFB-BD-COF film in S1 is as follows: S11, first weigh trimesaldehyde and 4,4-diaminobenzidine separately, add them to dichloromethane, and stir them magnetically for 1-2 hours to fully mix them; wherein the weight ratio of trimesaldehyde to dichloromethane is 1:(600-700); The weight ratio of 4,4-diaminobiphenyl to dichloromethane is 1:(350-450); S12. The obtained trimesaldehyde and 4,4-diaminobiphenyl solution are mixed in a molar ratio of 1:(1-2), and deionized water and 3M acetic acid aqueous solution are added. The interface is allowed to stand to form a film. After the film is formed, it is taken out, soaked and washed with tetrahydrofuran several times, and then dried in a vacuum oven at 60-80°C to obtain a TFB-BD-COF film.

[0012] Preferably, the specific process for preparing the COC solution in S2 is as follows: Add COC particles to xylene at a weight ratio of 1:(20-30) and stir magnetically in an oil bath at 50-70°C for 1-2 hours to fully dissolve the particles. Preferably, the specific process of blending film in S3 is as follows: The dissolved solution in S2 is evenly spread on a glass slide and vacuum dried at 60-80°C to form a film. The TFB-BD-COF film obtained in S1 is then ground into powder and dissolved in xylene. It is magnetically stirred to disperse it evenly and then coated on the COC film according to the corresponding weight ratio. It is vacuum dried again at 60-80°C to obtain a high-temperature resistant and low-dielectric composite film.

[0013] By adopting the above technical solution, the high temperature resistant low dielectric composite film obtained by the above steps has excellent dielectric properties and mechanical strength. The specific reasons are as follows: 1) Using interfacial polymerization to form highly crystalline COF films; TFB and BD undergo condensation reaction at the interface between dichloromethane and aqueous acetic acid solution to form a highly ordered covalent organic framework (COF) film; This method can precisely control the stacking of molecular layers to form films with high porosity and high crystallinity, which is conducive to achieving low dielectric constant and excellent thermal stability; 2) Precise control of reactant ratios and solvent systems; The weight ratios of trimesaldehyde to dichloromethane and 4,4'-diaminobenzidine to dichloromethane (1:600-700 and 1:350-450) were clearly defined to ensure moderate reactant concentrations and facilitate uniform film formation. The addition of deionized water and aqueous acetic acid to regulate the reaction environment facilitated the smooth progress of the interfacial polymerization reaction and improved film quality. 3) Complementary advantages form high temperature resistant and low dielectric composite materials; TFB-BD-COF provides high porosity, low dielectric constant and high thermal stability; COC provides excellent mechanical strength, flexibility and processing performance; through a reasonable blending film formation method, the two materials achieve complementary and synergistic enhancement in structure and performance.

[0014] In a third aspect, the present application provides an application of a high-temperature resistant low-dielectric composite film or a product obtained by any of the above preparation methods in microelectronic dielectric materials, products and equipment.

[0015] In a fourth aspect, the present application provides a high-temperature resistant, low-dielectric TFB-BD-COF film, which is prepared by interfacial polymerization of trimesaldehyde and 4,4-diaminobiphenyl, as follows: First, weigh trimesaldehyde and 4,4-diaminobenzene separately and add them to dichloromethane; then stir magnetically for 1-2 hours to mix them thoroughly; wherein the weight ratio of trimesaldehyde to dichloromethane is 1:(600-700); The weight ratio of 4,4-diaminobiphenyl to dichloromethane is 1:(350-450); The obtained trimesaldehyde and 4,4-diaminobiphenyl solution were mixed in a molar ratio of 1:(1-2), and deionized water and 3M acetic acid aqueous solution were added. The interface was allowed to stand to form a film. After the film was formed, it was taken out, soaked and washed several times with tetrahydrofuran, and then dried in a vacuum oven at 60-80°C to obtain a TFB-BD-COF film.

[0016] In summary, this application has the following beneficial effects: 1. In this application, the composite film prepared by adding cyclic olefin copolymer COC to the TFB-BD-COF film prepared by interfacial polymerization of trimesaldehyde and 4,4-diaminobiphenyl synergistically achieves ultra-low dielectric constant, low dielectric loss, good thermal stability and mechanical properties. 2. Through interfacial polymerization, trimesaldehyde (TFB) and 4,4'-diaminobiphenyl (BD) are precisely polymerized at the nanoscale to form a highly ordered covalent organic framework (COF) film; When COF is further compounded with cyclic olefin copolymer (COC), the nano-confinement effect between the flexible segments of COC and the rigid skeleton of COF is utilized to form a "rigid and flexible" interface structure; This structure can simultaneously suppress charge polarization (reducing the dielectric constant), block charge transfer paths (reducing dielectric loss), and enhance mechanical strength and thermal stability through interfacial interactions, breaking through the bottleneck of traditional composite materials where one performance trades off another. 3. By regulating the porosity (microporous structure) of COF and the crystallinity of COC, a multi-scale pore structure (microporous COF + mesoporous COC) is constructed, significantly reducing the polarization effect. At the same time, the glass transition temperature (Tg) of COC complements the thermal stability of COF, maintaining low loss characteristics (e.g., tanδ < 0.005 @ 1 GHz) at high temperatures. 4. The high-temperature resistant low-dielectric composite film prepared by the process of this application has stable and uniform performance and excellent dielectric properties and mechanical strength, that is, it achieves an ultra-low dielectric constant, small dielectric loss, good thermal stability and mechanical properties, and is suitable for industrial production; 5. Compared with other low-dielectric polymer materials, the TFB-BD-COF film provided in this application provides better stability, flexibility and processability, and can serve as a multifunctional platform to develop new dielectric materials for different electronic applications, including long-life flexible and portable devices, and has wide applications in fields such as microelectronics. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 TG curve (a) and DTG curve (b) of the TFB-BD-COF film in Preparation Example 1; Figure 2 FTIR spectrum of raw material TFB (a), raw material BD (b), and TFB-BD-COF film (c) in the preparation of TFB-BD-COF film in Example 1; Figure 3 is the XRD spectrum of the TFB-BD-COF film in Preparation Example 1; Figure 4 This is the SEM image of the TFB-BD-COF film prepared in Example 1; Figure 5 The dielectric constant curve (a) and dielectric loss curve (b) of the TFB-BD-COF film prepared in Example 1; Figure 6 FTIR spectra of pure COC film (a) and TFB-BD-COF / COC composite films in Examples 1-5 (b, c, d, e, f); Figure 7 The dielectric constant curve (a) and dielectric loss curve (b) of the TFB-BD-COF film in Preparation Example 1 and the TFB-BD-COF / COC composite films in Examples 1-5 are shown. DETAILED DESCRIPTION

[0018] The following is a combination of the embodiments and the appended Figure 1 -Attached Figure 7To further explain this application in detail, the raw materials used in this application are all common commercially available materials except for some specifications that are clearly limited.

[0019] Preparation Example 1 A high-temperature resistant, low-dielectric TFB-BD-COF film is prepared by interfacial polymerization of trimesaldehyde and 4,4-diaminobiphenyl, as follows: First, weigh trimesaldehyde and 4,4-diaminobenzene separately, add them into dichloromethane, and stir them magnetically for 1 hour to mix them thoroughly. The amounts of trimesaldehyde and dichloromethane used were 0.18 mmol and 15 ml respectively; The amounts of 4,4-diaminobiphenyl and dichloromethane used were 0.27 mmol and 15 ml, respectively; The obtained trimesaldehyde and 4,4-diaminobenzene solution were mixed in a molar ratio of 1:1.5, and 20 ml of deionized water and 1.2 ml of 3M acetic acid aqueous solution were added. The mixture was allowed to stand for 4-5 days until a film was formed on the interface. After the film was formed, the mixture was taken out, soaked and washed with tetrahydrofuran several times, and then dried in a vacuum oven at 70°C to obtain the product.

[0020] Then the TFB-BD-COF film and its raw materials obtained in Preparation Example 1 were subjected to thermogravimetric analysis, dielectric properties analysis, XRD, FTIR, and SEM structure analysis. Figure 1-5 , as follows: Depend on Figure 1 (a) (TG curve of TFB-BD-COF film) and Figure 1 (b) (DTG curve of TFB-BD-COF film) It can be seen that: due to the decomposition of the solvent, its initial weight loss below 100°C is 0.3%. It remains stable before 450°C, and begins to decrease above this temperature, reaching the maximum value of the weight loss rate at 505°C, that is, the TFB-BD-COF film has good thermal stability.

[0021] Depend on Figure 2 (a) (FTIR spectrum of raw material TFB), Figure 2 (b) (FTIR spectrum of raw material BD) and Figure 2 (c) (FTIR spectrum of TFB-BD-COF film) shows that: exist Figure 2 (a) 3061 and 1693 cm -1 , are the peaks of C-H and HC=O of TFB stretching vibration respectively; Figure 2 (b) at 3220 cm -1 The above shows multiple absorption peaks, and the bending vibration of N-H overlaps with the vibration of the benzene ring skeleton, at 1629 and 1503 cm-1 There are two broad absorption peaks.

[0022] Figure 2 (c) at 1621 cm -1 and 1485cm -1 The peaks at 3 and 4 are the C=N and C-N stretching vibrations of TFB-BD-COF, respectively. This confirms the formation of imine groups due to the condensation of aldehyde and amine groups.

[0023] Depend on Figure 3 (XRD spectrum of TFB-BD-COF film) It can be seen that: the figure shows its characteristic strong peak at 2θ of 3.58°, which corresponds to (100) of the hexagonal phase of TFB-BD-COF, and other peaks appear at 2θ of 6.19° and 7.15°, which correspond to (110) and (200) of the hexagonal phase of TFB-BD-COF, respectively.

[0024] Depend on Figure 4 (SEM image of TFB-BD-COF film) It can be seen that: The image shows that TFB-BD-COF has agglomerated spheres of different sizes. This type of morphology is important for reducing the dielectric constant because they can accommodate a large number of air voids between them.

[0025] Depend on Figure 5 (a) (Dielectric constant curve of TFB-BD-COF film) and Figure 5 (b) (Dielectric constant curve of TFB-BD-COF film) shows that: Figure 5 (a) The dielectric constant curve of TFB-BD-COF at 10 2 Hz~10 4 In the Hz frequency range, it tends to be stable overall, with only a slight decrease, and its dielectric constant drops from 2.17 to 2.14.

[0026] As the frequency increases, at 10 4 Hz~3×10 5 Hz frequency range, the dielectric constant curve of TFB-BD-COF shows a downward trend, and its dielectric constant decreases from 2.14 to 2.04. 5 At Hz, its dielectric constant curve tends to be stable again.

[0027] Figure 5 (b) In 10 2 Hz~5×10 4 In the Hz frequency range, the dielectric loss of TFB-BD-COF increases slowly with the increase of frequency. 4 The peak value is 0.024 at Hz, and the peak value is 0.024 at frequencies greater than 5×104 Hz, the dielectric loss decreases slightly, and at 2×10 5 Hz and then stabilized.

[0028] In summary, it can be concluded that the prepared TFB-BD-COF film has an ultra-low dielectric constant, small dielectric loss and good thermal stability. Compared with other low-dielectric polymer materials, it provides better stability, flexibility and processability. As a multifunctional platform, TFB-BD-COF film can be used to develop new dielectric materials for different electronic applications.

[0029] Example 1 A method for preparing a high-temperature resistant low-dielectric composite film, comprising the following steps: S1, TFB-BD-COF film: prepared in Preparation Example 1; S2. Prepare COC solution: add 50 mg of COC particles into 1.5 ml of dimethylbenzene (DMB) and stir magnetically in an oil bath at 60°C for 1 hour to fully dissolve the particles. The COC particles are Polyplastics TOPAS COC, with a volume resistivity of >1.0*10 16 , dissipation factor (7.0*10 (-5) , 1.00 GHz), tracking index>600, transmittance 92%.

[0030] S3. Blending film formation: Grind the TFB-BD-COF film in S1 into powder and dissolve it in xylene (DMB). Use magnetic stirring to evenly disperse it. Mix it with the xylene solution of COC at a relative mass of 2%, and control each solution to be 1.5 ml. After magnetic stirring for 30 minutes, spread the mixed solution evenly on a glass slide and vacuum dry it at 70°C to obtain a composite film.

[0031] Example 2 A method for preparing a high-temperature resistant low-dielectric composite film, comprising the following steps: S1, TFB-BD-COF film: prepared in Preparation Example 1; S2. Prepare COC solution: add 50 mg of COC particles into 1.5 ml of dimethylbenzene (DMB) and stir magnetically in an oil bath at 60°C for 1 hour to fully dissolve the particles. The COC particles are Polyplastics TOPAS COC, with a volume resistivity of >1.0*10 16 , dissipation factor (7.0*10 (-5) , 1.00 GHz), tracking index>600, transmittance 92%.

[0032] S3. Blending film: Grind the TFB-BD-COF film in S1 into powder and dissolve it in xylene (DMB). Use magnetic stirring to make it evenly dispersed. Mix it with the xylene solution of COC at a relative mass of 4%. Control each solution to be 1.5 ml. After magnetic stirring for 30 minutes, spread the mixed solution evenly on a glass slide and vacuum dry it at 70°C to obtain a composite film.

[0033] Example 3 A method for preparing a high-temperature resistant low-dielectric composite film, comprising the following steps: S1, TFB-BD-COF film: prepared in Preparation Example 1; S2. Prepare COC solution: add 50 mg of COC particles into 1.5 ml of dimethylbenzene (DMB) and stir magnetically in an oil bath at 60°C for 1 hour to fully dissolve the particles. The COC particles are Polyplastics TOPAS COC, with a volume resistivity of >1.0*10 16 , dissipation factor (7.0*10 (-5) , 1.00 GHz), tracking index>600, transmittance 92%.

[0034] S3. Blending film: Grind the TFB-BD-COF film in S1 into powder and dissolve it in xylene (DMB). Use magnetic stirring to disperse it evenly. Mix it with the xylene solution of COC at a relative mass of 6%. Control each solution to be 1.5 ml. After magnetic stirring for 30 minutes, spread the mixed solution evenly on a glass slide and vacuum dry it at 70°C to obtain a composite film.

[0035] Example 4 A method for preparing a high-temperature resistant low-dielectric composite film, comprising the following steps: S1, TFB-BD-COF film: prepared in Preparation Example 1; S2. Prepare COC solution: add 50 mg of COC particles into 1.5 ml of dimethylbenzene (DMB) and stir magnetically in an oil bath at 60°C for 1 hour to fully dissolve the particles. The COC particles are Polyplastics TOPAS COC, with a volume resistivity of >1.0*10 16 , dissipation factor (7.0*10 (-5) , 1.00 GHz), tracking index>600, transmittance 92%.

[0036] S3. Blending film: Grind the TFB-BD-COF film in S1 into powder and dissolve it in xylene (DMB). Use magnetic stirring to make it evenly dispersed. Mix it with the xylene solution of COC at a relative mass of 8%. Control each solution to be 1.5 ml. After magnetic stirring for 30 minutes, spread the mixed solution evenly on a glass slide and vacuum dry it at 70°C to obtain a composite film.

[0037] Example 5 A method for preparing a high-temperature resistant low-dielectric composite film, comprising the following steps: S1, TFB-BD-COF film: prepared in Preparation Example 1; S2. Prepare COC solution: add 50 mg of COC particles into 1.5 ml of dimethylbenzene (DMB) and stir magnetically in an oil bath at 60°C for 1 hour to fully dissolve the particles. The COC particles are Polyplastics TOPAS COC, with a volume resistivity of >1.0*10 16 , dissipation factor (7.0*10 (-5) , 1.00 GHz), tracking index>600, transmittance 92%.

[0038] S3. Blending film: Grind the TFB-BD-COF film in S1 into powder and dissolve it in xylene (DMB). Use magnetic stirring to disperse it evenly. Mix it with the xylene solution of COC at a relative mass of 10%. Control each solution to be 1.5 ml. After magnetic stirring for 30 minutes, spread the mixed solution evenly on a glass slide and vacuum dry it at 70°C to obtain a composite film.

[0039] The dielectric properties of the above-mentioned Examples 1-5, i.e., the mixed films containing different percentages of TFB-BD-COF and the pure COC films, were analyzed, and the structure and performance of the films were characterized by FTIR, etc., to explore the effect of the TFB-BD-COF content on the dielectric properties and thermal stability of the films. Figure 6-7 , the analysis is as follows: Depend on Figure 6 (a) (Pure COC film) It can be seen that the pure COC film does not contain C=N bonds; Figure 6 (b) (FTIR spectrum of TFB-BD-COF / COC composite film in Example 1) It can be seen that the FTIR spectrum of the 2% mass fraction TFB-BD-COF / COC composite film has a peak at 1627 cm -1 The C=N bond with stretching vibration occurs at Figure 6(c) (FTIR spectrum of TFB-BD-COF / COC composite film in Example 2) It can be seen that the FTIR spectrum of the 4% mass fraction TFB-BD-COF / COC composite film has a peak at 1599 cm -1 The C=N bond with stretching vibration occurs at Figure 6 (d) (FTIR spectrum of TFB-BD-COF / COC composite film in Example 3) It can be seen that the FTIR spectrum of the 6% mass fraction TFB-BD-COF / COC composite film has a peak at 1626 cm -1 The C=N bond with stretching vibration occurs at Figure 6 (e) (FTIR spectrum of TFB-BD-COF / COC composite film in Example 4) It can be seen that the FTIR spectrum of the 8% mass fraction TFB-BD-COF / COC composite film has a peak at 1621 cm -1 The C=N bond with stretching vibration occurs at Figure 6 (f) (FTIR spectrum of TFB-BD-COF / COC composite film in Example 5) It can be seen that the FTIR spectrum of the 10% mass fraction TFB-BD-COF / COC composite film has a peak at 1634 cm -1 The C=N bond with stretching vibration occurs at In summary, it can be seen that the thermal stability of the film can be effectively increased by preparing TFB-BD-COF / COC composite film by blending TFB-BD-COF and COC.

[0040] Depend on Figure 7 (a) (dielectric constant curves of the TFB-BD-COF film in Preparation Example 1 and the TFB-BD-COF / COC composite films in Examples 1-5) shows that: The dielectric constant of pure COC film is around 3.7. When the mass fraction of TFB-BD-COF in the TFB-BD-COF / COC composite film is 6% or less, the dielectric constant of the TFB-BD-COF / COC composite film gradually decreases with the increase of TFB-BD-COF mass fraction, reaching a minimum value of 2.6 at a TFB-BD-COF mass fraction of 6%. This indicates that adding high-porosity TFB-BD-COF to COC to prepare TFB-BD-COF / COC composite films can effectively reduce the dielectric constant of the film. However, when the mass fraction of TFB-BD-COF is above 6%, the dielectric constant of the TFB-BD-COF / COC composite film increases slightly with the increase of the TFB-BD-COF mass fraction. It is speculated that this is because the COC produced by the manufacturer contains more additives. When filled with a high content of COF, due to the large number of voids, the additives that should have volatilized enter the COF voids and cannot escape, thereby leading to an increase in the dielectric constant.

[0041] Depend on Figure 7 (b) (dielectric loss curves of the TFB-BD-COF film in Preparation Example 1 and the TFB-BD-COF / COC composite films in Examples 1-5) shows that: When the mass fraction of TFB-BD-COF is 4% or less and 10%, the addition of different mass fractions of TFB-BD-COF has little effect on the dielectric loss of TFB-BD-COF / COC composite film. However, when the mass fraction of TFB-BD-COF is 6% and 8%, when the frequency is 10 4 When the frequency is below Hz, it has a greater impact on the dielectric loss of the TFB-BD-COF / COC composite film. It is speculated that this is because relatively large particles of TFB-BD-COF still exist after grinding and ultrasonic treatment, and exist in the TFB-BD-COF / COC composite films with TFB-BD-COF mass fractions of 6% and 8%, thereby leading to an increase in the dielectric loss of the TFB-BD-COF / COC composite film.

[0042] In summary, it can be seen that the preparation of TFB-BD-COF / COC composite film by blending TFB-BD-COF and COC can effectively improve the dielectric properties of the film, which has an ultra-low dielectric constant and small dielectric loss.

[0043] Mechanical properties test-specimen preparation method: The TFB-BD-COF film obtained in S1 was ground and dispersed in DMB. After mixing, it was added to the COC solution at a TFB-BD-COF content of 6% and mixed to obtain a COF-COC mixed solution. The mixed solution was introduced into a dumbbell-shaped metal mold in batches, with each batch adding about 500 microns of solution. The mold was then placed in a vacuum drying oven for vacuum drying (drying conditions: temperature: 60°C; pressure: -0.09 to -0.095 MPa; time: 1 hour). The COF-COC mixed solution was then added again and the mold was placed in a vacuum drying oven for vacuum drying. This process was repeated until a smooth casting was formed in the metal mold. Finally, the metal mold was placed in a vacuum drying oven again, the temperature was set to 80°C, the vacuum pressure was set to -0.096 to -0.1 MPa, and maintained for 2 hours. After natural cooling, the mold was removed to obtain the COF-COC high-temperature resistant and low-dielectric molding material.

[0044] The obtained COF-COC molding material was tested using an electronic universal mechanical testing machine (model: E44.304, manufacturer: MTS Industrial Systems (China) Co., Ltd.) and the results are as follows:

[0045] The above results show that when pure COF is processed into splines, it exhibits premature brittle fracture due to its high brittleness; when COF is used in combination with COC in an additive form, the mechanical test of the cast body is normal, with no brittle fracture behavior, and it has a strength of 57MPa and a modulus of 2559MPa, can be processed and formed, and has good application prospects.

[0046] The above are all modifications that a person skilled in the art can make to this embodiment as needed after reading this specification, which do not contribute creatively or solutions that obviously constitute technical inspiration. However, as long as they are within the scope of the claims of this application, they should be protected by patent law.

Claims

1. A high temperature resistant low dielectric composite film, characterized in that: The invention comprises a TFB-BD-COF film prepared by interfacial polymerization of trimesaldehyde and 4,4-diaminobiphenyl.

2. The high temperature resistant low dielectric composite film according to claim 1, characterized in that: The TFB-BD-COF has a hexagonal phase structure; The XRD spectrum has characteristic peaks at 2θ=3.58°, 6.19°, and 7.15°, and the porosity is ≥60%.

3. The high temperature resistant low dielectric composite film according to claim 1, characterized in that: Also included is cyclic olefin copolymer COC, wherein the volume resistivity of the COC is greater than 1.0*10 16 , dissipation factor (7.0*10 (-5) , 1.00GHz), tracking index>600, light transmittance 92%.

4. The high temperature resistant low dielectric composite film according to claim 3, characterized in that: The weight ratio of the TFB-BD-COF film to the COC particles is 1:(10-50).

5. A method for preparing a high temperature resistant low dielectric composite film, characterized in that: Here are the steps: S1. Preparation of TFB-BD-COF film: Dissolve TFB and BD in dichloromethane separately, stir and mix, then add 3M acetic acid aqueous solution, let stand for 4-5 days to form a film, wash and dry to obtain; S2. Prepare COC solution: dissolve COC granules in xylene, heat and stir until dissolved; S3, blending film formation: grind the TFB-BD-COF film obtained in S1 and disperse it in DMB. After mixing evenly, mix it with the COC solution obtained in S2 according to the corresponding weight ratio. After mixing evenly, apply and vacuum dry to obtain a composite film.

6. The method for preparing a high temperature resistant low dielectric composite film according to claim 5, characterized in that: The specific process for preparing the TFB-BD-COF film in S1 is as follows: S11, first weigh trimesaldehyde and 4,4-diaminobenzidine separately, add them to dichloromethane, and stir them magnetically for 1-2 hours to fully mix them; wherein the weight ratio of trimesaldehyde to dichloromethane is 1:(600-700); The weight ratio of 4,4-diaminobiphenyl to dichloromethane is 1:(350-450); S12. The obtained trimesaldehyde and 4,4-diaminobiphenyl solution are mixed in a molar ratio of 1:(1-2), and deionized water and 3M acetic acid aqueous solution are added. The interface is allowed to stand to form a film. After the film is formed, it is taken out, soaked and washed with tetrahydrofuran several times, and then dried in a vacuum oven at 60-80°C to obtain a TFB-BD-COF film.

7. The method for preparing a high temperature resistant low dielectric composite film according to claim 5, characterized in that: The specific process for preparing the COC solution in S2 is as follows: The COC particles were added to xylene in a weight ratio of 1:(20-30) and magnetically stirred in an oil bath at 50-70° C. for 1-2 hours to fully dissolve the particles.

8. An application of a high temperature resistant low dielectric composite film, characterized in that: The invention relates to the use of the high-temperature resistant low-dielectric composite film described in any one of claims 1 to 4 or the high-temperature resistant low-dielectric composite film obtained by the preparation method of any one of claims 5 to 7 in microelectronic dielectric materials, products and equipment.

Images