Polyimide composite film, and preparation method and application thereof

Abstract

The application provides a polyimide composite film and a preparation method and application thereof, and belongs to the technical field of integrated circuit low dielectric. The application provides a preparation method of a polyimide composite film, which comprises the following steps: mixing a polyamide acid solution, a covalent organic framework material powder and an organic solvent to obtain a mixed solution; and performing electrostatic spinning and solidification on the mixed solution in sequence to obtain the polyimide composite film. The application takes PI as a matrix, provides good mechanical property support for the composite film, and solves the high dielectric loss problem caused by adding porous inorganic materials due to the good compatibility of the covalent organic framework material and the PI, so that the polyimide composite film has ultralow dielectric constant and ultralow dielectric loss.

Description

Technical Field

[0001] This invention belongs to the field of low dielectric technology of integrated circuits, specifically relating to a polyimide composite film, its preparation method, and its application. Background Technology

[0002] Polyimide (PI) is a high-performance polymer with high mechanical strength and modulus, providing excellent mechanical support for composite materials. PI also exhibits strong thermal stability, maintaining its properties at high temperatures. However, traditional PI has a high dielectric constant, necessitating the addition of porous inorganic materials to introduce air and reduce the dielectric constant. However, incompatibility issues exist between inorganic materials and the PI matrix, leading to high losses. Therefore, improving the dielectric properties of polyimide films to reduce dielectric constant has become a pressing technical challenge in this field. Summary of the Invention

[0003] The purpose of this invention is to provide a polyimide composite film, its preparation method, and its applications. The polyimide composite film prepared by the method provided by this invention possesses ultra-low dielectric constant and ultra-low dielectric loss.

[0004] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a polyimide composite film, comprising the following steps: (1) Mix polyamic acid solution, covalent organic framework material powder and organic solvent to obtain a mixed solution; (2) The mixed solution obtained in step (1) is subjected to electrospinning and curing in sequence to obtain a polyimide composite film.

[0005] Preferably, the intrinsic dielectric constant of the covalent organic framework material powder in step (1) is 1.5~2.0, and the particle size of the covalent organic framework material powder is 200~500nm.

[0006] Preferably, the chemical structure of the covalent organic framework material powder in step (1) is as shown in Formula I: Formula I.

[0007] Preferably, the method for preparing the covalent organic framework material powder is as follows: A covalent organic framework material powder was obtained by mixing amino monomers, aldehyde monomers, acidic catalysts and organic solvents and then carrying out Schiff base condensation reaction.

[0008] Preferably, the amino monomer is 5''-(4'-amino-[1,1'-biphenyl]-4-yl)-[1,1':4',1'':3'',1''':4''',1''''-pentaphenyl]-4,4''''-diamine; the aldehyde monomer is pyromellitic methyl ether; and the molar ratio of the amino monomer to the aldehyde monomer is (1~5):(5~1).

[0009] Preferably, the Schiff base condensation reaction is carried out at room temperature for 2 to 3 days.

[0010] Preferably, in step (1), the mass of the covalent organic framework material powder is 0.5 to 3% of the mass of the polyimide matrix in the polyimide composite film.

[0011] Preferably, the curing temperature in step (2) is 200~300℃ and the curing time is 20~24h.

[0012] The present invention also provides a polyimide composite film prepared by the preparation method described in the above technical solution.

[0013] The present invention also provides the application of the polyimide composite film described above in the field of low dielectric.

[0014] This invention provides a method for preparing a polyimide composite film, comprising the following steps: mixing a polyamic acid solution, a covalent organic framework material powder, and an organic solvent to obtain a mixed solution; and sequentially subjecting the mixed solution to electrospinning and curing to obtain a polyimide composite film. This invention uses PI as a matrix, providing good mechanical property support for the composite film. Simultaneously, the good compatibility between the covalent organic framework material and PI solves the problem of high dielectric loss caused by the addition of porous inorganic materials, thereby enabling the polyimide composite film to possess ultra-low dielectric constant and ultra-low dielectric loss. Experimental results show that the polyimide composite film prepared by this invention possesses ultra-low dielectric constant and ultra-low dielectric loss. Attached Figure Description

[0015] Figure 1 The image shows the XRD pattern of the covalent organic framework material powder in Example 1. Figure 2 The FT-IR spectrum of the covalent organic framework material powder in Example 1; Figure 3 Broadband graph of the dielectric constant of the polyimide composite film prepared in Example 1; Figure 4 Broadband graph of dielectric loss of the polyimide composite film prepared in Example 1. Detailed Implementation

[0016] This invention provides a method for preparing a polyimide composite film, comprising the following steps: (1) Mix polyamic acid solution, covalent organic framework material powder and organic solvent to obtain a mixed solution; (2) The mixed solution obtained in step (1) is subjected to electrospinning and curing in sequence to obtain a polyimide composite film.

[0017] Unless otherwise specified, the present invention does not impose any special restrictions on the source of the raw materials, and commercially available products well known to those skilled in the art can be used.

[0018] This invention involves mixing a polyamic acid solution, covalent organic framework (COF) material powder, and an organic solvent to obtain a mixed solution. This invention also involves uniformly dispersing the covalent organic framework (COF) material in a PAA solution.

[0019] In this invention, the preferred method for preparing the polyamic acid (PAA) solution is as follows: A polycondensation reaction is carried out after mixing diamine monomer, dianhydride monomer and organic solvent to obtain polyamic acid solution.

[0020] In this invention, the diamine monomer is preferably 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane; the dianhydride monomer is preferably 4,4′-(hexafluoroisopropene)phthalic anhydride; and the molar ratio of the diamine monomer to the dianhydride monomer is preferably 1:1.

[0021] This invention does not impose any particular limitation on the type of organic solvent; any organic solvent well-known to those skilled in the art can be used. As one embodiment, the organic solvent may be DMAC.

[0022] This invention does not impose a specific limit on the amount of organic solvent used, as long as the raw materials are completely dissolved. As one embodiment, the solid content of the polyamic acid solution can be 15-20%.

[0023] The present invention does not have any special limitations on the operation of mixing the diamine monomer, dianhydride monomer and organic solvent, and any technical solution for preparing the mixture well known to those skilled in the art can be used.

[0024] In this invention, the polycondensation reaction is preferably carried out under ice bath conditions; the polycondensation reaction time is preferably 10-20 hours. As one embodiment, the polycondensation reaction time can be 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, or 19 hours.

[0025] In this invention, the intrinsic dielectric constant of the covalent organic framework material powder is preferably 1.5 to 2.0; the particle size of the covalent organic framework material powder is preferably 200 to 500 nm. By limiting the intrinsic dielectric constant of the covalent organic framework material powder to the above range, this invention satisfies the characteristic of low dielectric constant in polyimide films.

[0026] As one embodiment, the particle size of the covalent organic framework material powder can be 300 nm or 400 nm.

[0027] In this invention, the chemical structure of the covalent organic framework material powder is preferably as shown in Formula I: Formula I.

[0028] In this invention, the preferred method for preparing the covalent organic framework material powder is as follows: An amino monomer, an aldehyde monomer, an acidic catalyst, and an organic solvent are mixed and subjected to a Schiff base condensation reaction to obtain a covalent organic framework material powder. In this invention, an amino monomer and an aldehyde monomer construct an imine-linked covalent organic framework material through a Schiff base condensation reaction under acidic catalytic conditions.

[0029] In this invention, the amino monomer is preferably 5''-(4'-amino-[1,1'-biphenyl]-4-yl)-[1,1':4',1'':3'',1''':4''',1'''-pentaphenyl]-4,4''''-diamine; and the aldehyde monomer is preferably pyromellitic methyl ester.

[0030] In this invention, the structural formula of the 5''-(4'-amino-[1,1'-biphenyl]-4-yl)-[1,1':4',1'':3'',1''':4''',1''''-pentaphenyl]-4,4''''-diamine is shown in Formula II: Formula II.

[0031] In this invention, the structural formula of the pyromellitic methyl ether is shown in Formula III: Formula III.

[0032] In this invention, the preferred molar ratio of the amino monomer to the aldehyde monomer is (1~5):(5~1). As one embodiment, the molar ratio of the amino monomer to the aldehyde monomer can be 1:1.

[0033] In this invention, the acidic catalyst preferably comprises one or more of an aqueous solution of acetic acid, an aqueous solution of trifluoroacetic acid, and an aqueous solution of p-toluenesulfonic acid; the concentration of the acidic catalyst is preferably 3-12 mol / L. As one embodiment, the concentration of the acidic catalyst can be 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, 10 mol / L, or 11 mol / L.

[0034] In this invention, the volume ratio of the acidic catalyst to the molar amount of the amino monomer is preferably (3~4) mL:(0.5~1) mmol, more preferably 3.3 mL:0.8 mmol.

[0035] This invention does not impose any particular limitation on the type of organic solvent used; any organic solvent well-known to those skilled in the art can be used. As one embodiment, the organic solvent may be n-butanol. This invention does not impose any particular limitation on the amount of organic solvent used, as long as the raw material is completely dissolved.

[0036] The present invention does not impose any special limitations on the operation of mixing the amino monomer, aldehyde monomer, acid catalyst and organic solvent, and any technical solution for preparing the mixture well known to those skilled in the art can be used.

[0037] In this invention, the preferred temperature for the Schiff base condensation reaction is room temperature; the preferred time for the Schiff base condensation reaction is 2 to 3 days.

[0038] After the Schiff base condensation reaction is completed, the present invention preferably performs post-processing on the product obtained by the Schiff base condensation reaction to obtain covalent organic framework material powder.

[0039] In this invention, the post-processing preferably includes sequentially performing filtration, washing, and drying.

[0040] The present invention does not impose any special limitations on the filtration operation; any operation known to those skilled in the art can be used to obtain the filter residue.

[0041] The present invention does not impose any particular limitations on the washing operation; the goal is simply to remove impurities. As one embodiment, the detergent used for washing can be THF or acetone.

[0042] The present invention does not impose any special limitations on the drying operation; drying to a constant weight is sufficient.

[0043] In this invention, the mass of the covalent organic framework material powder is preferably 0.5-3% of the mass of the polyimide matrix in the polyimide composite film. As one embodiment, the mass of the covalent organic framework material powder can be 1%, 1.5%, 2%, or 2.5% of the mass of the polyimide matrix in the polyimide composite film.

[0044] This invention does not impose any particular limitation on the type of organic solvent used; any organic solvent well-known to those skilled in the art can be used. As one embodiment, the organic solvent may be DMAC. This invention does not impose any particular limitation on the amount of organic solvent used, as long as the raw material is completely dissolved.

[0045] In this invention, the mixing of the polyamic acid solution, the covalent organic framework material powder, and the organic solvent is preferably carried out by mixing the covalent organic framework material powder and the organic solvent to obtain a mixture, and then mixing the mixture with the polyamic acid solution.

[0046] In this invention, the mixing time between the mixture and the polyamic acid solution is preferably 0.5 to 20 hours; the mixing temperature between the mixture and the polyamic acid solution is preferably room temperature.

[0047] After obtaining the mixed solution, the present invention sequentially performs electrospinning and curing on the mixed solution to obtain a polyimide composite film.

[0048] The present invention does not impose any special limitations on the electrospinning operation; any operation well known to those skilled in the art can be used. The present invention prepares a fiber membrane from a mixed solution through electrospinning.

[0049] As one implementation method, the electrospinning process parameters can be: applied voltage of 10~20kV, flow rate of 1mL / h, and working distance of 15cm; the electrospinning can be carried out at room temperature.

[0050] In this invention, the curing temperature is preferably 200~300℃; the curing time is preferably 20~24h. As one embodiment, the curing temperature can be 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃ or 290℃; the curing time can be 21h, 22h or 23h.

[0051] Polyimide (PI) is a high-performance polymer with high mechanical strength and modulus, providing good mechanical support for composite materials. At the same time, PI has strong thermal stability and can maintain its performance under high temperature conditions. COF / PI composite films have high mechanical strength and low dielectric constant and dielectric loss, which provides favorable conditions for their application in low dielectric fields.

[0052] This invention prepares a type of COF / PI composite film by electrospinning. By introducing COF nanoparticles of different mass percentages into polyimide, the mechanical and electrical properties of the composite film are changed, so that the COF / PI composite film not only has a controllable ultra-low dielectric constant, but also has ultra-low dielectric loss.

[0053] Compared with existing technologies, it has the following advantages: This invention uses pre-designed structures to combine covalent organic framework materials and polyimide, and then electrospins to generate a porous COF / PI composite film, achieving ultra-low dielectric constant and ultra-low dielectric loss.

[0054] This invention combines COF nanoparticles with a PI matrix, which exhibits excellent compatibility between the COF nanoparticles and the PI matrix, thus solving the high loss problem associated with traditional methods that involve adding inorganic fillers.

[0055] The present invention also provides a polyimide composite film prepared by the preparation method described in the above technical solution.

[0056] In this invention, the thickness of the polyimide composite film is preferably 60-90 μm. As one embodiment, the thickness of the polyimide composite film can be 65 μm, 70 μm, 75 μm, 80 μm, or 85 μm.

[0057] The polyimide composite film provided by the present invention has a dielectric constant of less than 2 and a dielectric loss of less than 0.01.

[0058] The present invention also provides the application of the polyimide composite film described above in the field of low dielectric.

[0059] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0060] The structural formula of the covalent organic framework material powder used in the examples is shown in Formula I, and the preparation method is as follows: 0.8 mmol of 5''-(4'-amino-[1,1'-biphenyl]-4-yl)-[1,1':4',1'':3'',1''':4''',1''''-pentaphenyl]-4,4''''-diamine and 0.8 mmol of pyromellitic aldehyde were dissolved in n-butanol, followed by the addition of 3.3 mL of 12M acetic acid aqueous solution. The mixture was then reacted at room temperature for 3 days. The product was washed multiple times with THF and acetone, and the product was collected. The yellow powder was dried under vacuum overnight to obtain a covalent organic framework material powder with a particle size of 200-500 nm.

[0061] Example 1 The preparation method of polyimide composite film is as follows: The diamine monomer 2,2-bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane and the dianhydride monomer 4,4′-(hexafluoroisopropene) diaphthalic anhydride were dissolved in DMAC in a molar ratio of 1:1, and then polycondensation was carried out under ice bath conditions for 20 h to obtain a polyamic acid solution with a solid content of 15%. Covalent organic framework material powder was added to a DMAC solution, dispersed evenly, and then added to a PAA solution. The mixture was stirred at room temperature for 20 hours to obtain a mixed solution. The mass of the covalent organic framework material powder was 2% of the mass of the polyimide matrix in the polyimide composite film. The mixed solution was electrospun into a fiber membrane, which was then cured at 280°C for 20 h to obtain a polyimide composite film. The electrospinning process parameters were: applied voltage of 10 kV, flow rate of 1 mL / h, and working distance of 15 cm. The electrospinning was carried out at room temperature.

[0062] Figure 1 The image shows the XRD pattern of the covalent organic framework material powder in Example 1.

[0063] from Figure 1 It can be seen that the obvious peak near 3.9° is a characteristic diffraction peak of COF, proving that the material was successfully synthesized and has high crystallinity.

[0064] Figure 2 The image shows the FT-IR spectrum of the covalent organic framework material powder in Example 1.

[0065] from Figure 2 It can be seen that 1621cm -1 The stretching vibration corresponding to the carbon-nitrogen double bond further proves that COF nanoparticles were successfully prepared.

[0066] Figure 3 Broadband graph of the dielectric constant of the polyimide composite film prepared in Example 1.

[0067] from Figure 3 It can be seen that the polyimide composite film provided by the present invention has an ultra-low dielectric constant.

[0068] Figure 4 Broadband graph of dielectric loss of the polyimide composite film prepared in Example 1.

[0069] from Figure 4 As can be seen, the polyimide composite film provided by the present invention has ultra-low dielectric loss.

[0070] As can be seen from the above embodiments, the polyimide composite film prepared by the preparation method provided by the present invention has ultra-low dielectric constant and ultra-low dielectric loss.

[0071] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a polyimide composite film, comprising the following steps: (1) Mix polyamic acid solution, covalent organic framework material powder and organic solvent to obtain a mixed solution; (2) The mixed solution obtained in step (1) is subjected to electrospinning and curing in sequence to obtain a polyimide composite film.

2. The preparation method according to claim 1, characterized in that, In step (1), the intrinsic dielectric constant of the covalent organic framework material powder is 1.5~2.0, and the particle size of the covalent organic framework material powder is 200~500nm.

3. The preparation method according to claim 1, characterized in that, The chemical structure of the covalent organic framework material powder in step (1) is shown in Formula I: Equation I.

4. The preparation method according to claim 3, characterized in that, The preparation method of the covalent organic framework material powder is as follows: A covalent organic framework material powder was obtained by mixing amino monomers, aldehyde monomers, acidic catalysts and organic solvents and then carrying out Schiff base condensation reaction.

5. The preparation method according to claim 4, characterized in that, The amino monomer is 5''-(4'-amino-[1,1'-biphenyl]-4-yl)-[1,1':4',1'':3'',1''':4''',1'''-pentaphenyl]-4,4''''-diamine; the aldehyde monomer is pyromellitic methyl ester; the molar ratio of the amino monomer to the aldehyde monomer is (1~5):(5~1).

6. The preparation method according to claim 4, characterized in that, The Schiff base condensation reaction was carried out at room temperature for 2-3 days.

7. The preparation method according to claim 1, characterized in that, In step (1), the mass of the covalent organic framework material powder is 0.5 to 3% of the mass of the polyimide matrix in the polyimide composite film.

8. The preparation method according to claim 1, characterized in that, The curing temperature in step (2) is 200~300℃ and the curing time is 20~24h.

9. The polyimide composite film prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the polyimide composite film of claim 9 in the field of low dielectric.

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