WO2022041361A1

WO2022041361A1 - Polyimide composite material and preparation method therefor and application thereof

Info

Publication number: WO2022041361A1
Application number: PCT/CN2020/116771
Authority: WO
Inventors: 李金辉; 张国平; 随裕莹; 孙蓉
Original assignee: 中国科学院深圳先进技术研究院
Priority date: 2020-08-28
Filing date: 2020-09-22
Publication date: 2022-03-03
Also published as: CN112029098A; CN112029098B

Abstract

Disclosed are a polyimide composite material and a preparation method therefor and an application thereof. The polyimide composite material comprises a polyimide matrix and a fluorinated carbon material distributed in the polyimide matrix; the fluorinated carbon material comprises any one or a combination of at least two of fluorinated graphene having a plane size of less than or equal to 10 μm, fluorinated nano carbon black having a diameter of less than or equal to 100 nm, or a fluorinated graphene quantum dot having a diameter of less than or equal to 10 nm.

Description

A kind of polyimide composite material and its preparation method and application

technical field

The present application relates to the technical field of packaging materials, for example, to a polyimide composite material and a preparation method and application thereof.

Background technique

Polyimide (PI) is widely used in aviation due to its excellent thermal stability, mechanical properties, chemical resistance, dimensional stability, low dielectric constant and loss, low water absorption and good adhesion. aerospace, microelectronics and other fields. In advanced semiconductor packaging, with the rapid development of advanced packaging processes such as fan-out wafer-level packaging and fan-out large board-level packaging, the need for polyimide layers with low dielectric constant, high transparency and low water absorption Intermediate dielectric materials put forward higher requirements. Among them, with the rapid development of high-frequency communications such as 5G, there is an urgent requirement for polyimide materials with low dielectric constant. Usually, the dielectric constant of polyimide can be reduced by introducing fluorine-containing dianhydride or diamine monomer, but it is expensive and thermal stability is reduced; The dielectric constant can be significantly reduced, but the presence of porous structures will lead to an increase in water absorption, which is detrimental to package reliability.

Taking advantage of the low polarizability of CF bonds and hydrophobicity of fluorinated nanomaterials such as fluorinated graphene, the addition of fluorinated graphene to polyimide further reduces the dielectric constant of polyimide and improves the hydrophobicity, and the addition of fluorinated graphene Its mechanical properties and heat resistance can be further improved and good optical transmittance can be maintained.

CN102604094A discloses a crosslinkable fluorine-containing polyimide and a preparation method thereof. The material is prepared by condensation polymerization and chemical imidization, and its raw materials and formula are composed (in parts by weight): 3-15 parts of 4-phenylacetylene phthalic anhydride, 10-20 parts of dianhydride compounds, fluorine-containing dianhydride 10-25 parts, 15-25 parts of diaminodiphenyl ether, 150-250 parts of N,N-dimethylacetamide, 50-70 parts of catalyst, 50-70 parts of dehydrating agent. The fluorine-containing groups on the surface of the material obtained by the invention are not easily enriched, the surface is ductile, and the body is hydrophobic. However, the raw materials used in the invention are expensive and the preparation cost is high, and the introduction of the obtained fluorine-containing dianhydride monomer is not conducive to the improvement of the thermal stability of the polyimide, and the mechanical properties are limited.

CN101429278A discloses a resin for encapsulating optical semiconductor elements comprising polyimide, the polyimide is prepared by mixing 5-norbornene-2,3-dianhydride or maleic anhydride, aliphatic tetracarboxylic dianhydride and The aliphatic diamine compound is prepared by imidizing the polyimide precursor obtained by the polycondensation reaction. The resin of the invention has excellent heat resistance and excellent light transmission properties. However, the dielectric properties, light transmittance, heat resistance and mechanical properties of the polyimide resin obtained by the invention all need to be further improved.

Therefore, according to the characteristics of the existing polyimide packaging materials, combined with the excellent properties of polyimide, such as high stability, a composite material was developed, which has low dielectric, high light transmittance, low water absorption, excellent heat resistance A series of comprehensive properties such as performance and mechanical properties are of great significance.

SUMMARY OF THE INVENTION

One of the objectives of the present application is to provide a polyimide composite material. The composite material has low dielectric, high light transmittance, low water absorption, high heat resistance and excellent mechanical properties.

For this purpose, the application adopts the following technical solutions:

The application provides a polyimide composite material, the polyimide composite material includes a polyimide matrix and a fluorocarbon material distributed in the polyimide matrix;

The fluorinated carbon material includes fluorinated graphene with a plane size ≤ 10 μm (eg 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, etc.), diameter ≤ 100 nm (eg 10 nm, 20 nm, 30 nm, 40 nm) ,50nm,60nm,70nm,80nm,90nm,etc any one or a combination of at least two. The combination can be a combination of fluorinated graphene and fluorinated nanocarbon black, a combination of fluorinated graphene and fluorinated graphene quantum dots, a combination of fluorinated nanocarbon black and fluorinated graphene quantum dots, or a combination of fluorinated graphene and fluorinated graphene quantum dots. A combination of graphene, fluorinated nanocarbon black, and fluorinated graphene quantum dots.

"Plane size" refers to the longest distance on the graphene plane. For example, the plane shape of graphene is a square, then the plane size is the diagonal length of the square. The square is only an example. The shape is not specifically limited. In addition, considering that the size of each sheet or particle in the carbon material cannot be exactly the same, the "planar size" and "diameter" are average values.

In this application, "fluorinated carbon material" refers to a fluorinated carbon material.

In the present application, the above three fluorinated carbon materials of specific sizes are introduced into the polyimide matrix. Within the size range defined in the present application, the dispersibility of the fluorinated nanomaterials can be improved and the optical transparency can be improved. Compared with the specified size The fluorinated carbon materials outside the range can effectively improve the synthesis of polyimide, so that it has both low dielectric, high light transmittance, low water absorption, high heat resistance and excellent mechanical properties.

Among them, if the plane size of fluorinated graphene is too large, it will lead to more serious stacking of nanomaterials, and because the size of nanomaterials is too large, it will lead to increased scattering and absorption of light, which is not conducive to lithography and optical transparency. For applications in other fields, the same is true for fluorinated nanocarbon black and fluorinated graphene quantum dots.

Optionally, the fluorinated graphene is single-layer fluorinated graphene.

Optionally, the thickness of the fluorinated graphene is less than or equal to 1 nm, for example, 0.1 nm, 0.2 nm, 0.3 nm, 0.4 nm, 0.5 nm, 0.6 nm, 0.7 nm, 0.8 nm, 0.9 nm, and the like.

Optionally, the fluorine to carbon ratios (F/C) of the fluorinated graphene, fluorinated nanocarbon black and fluorinated graphene quantum dots are each independently (0.1-1.5): 1, such as 0.2: 1, 0.4 :1, 0.6:1, 0.8:1, 1:1, 1.2:1, 1.4:1, etc., optional (0.5-1.15):1. The "fluorocarbon ratio" refers to the (molar) ratio of the amount of fluorine atoms to carbon atoms.

The present application can further improve the comprehensive performance of the polyimide composite material through the fluorocarbon ratio range of the above-mentioned fluorocarbon material. If the fluorocarbon ratio is too low, the dielectric constant will be too high, and the fluorocarbon ratio will be too high. Polyimide material with a dielectric constant, but the production cost will be significantly increased, and the decrease in the dielectric constant after exceeding 1.5:1 is not obvious.

Optionally, the fluorinated graphene with a plane size of ≤10 μm is obtained by a fluorination reaction of graphene oxide with a plane size of ≤10 μm.

Optionally, the graphene oxide is single-layer graphene oxide.

The commonly used method for preparing fluorinated graphene in the prior art is the exfoliation method, that is, the fluorinated graphene with a larger thickness is peeled off to obtain a relatively small fluorinated graphene, but this method often fails to obtain a single-layer fluorinated graphite. Graphene, and there is a problem of high oxygen content (low fluorocarbon ratio), and the application first prepares single-layer graphene, and then fluorination, compared with the peeling method, can obtain a single-layer fluorine with a high fluorocarbon ratio. Graphene, and the process is simpler.

Optionally, the graphene oxide with a plane size ≤ 10 μm exists in the form of an aerogel.

Optionally, the fluorinated nano carbon black with a diameter of ≤ 100 nm is obtained by a fluorination reaction of nano carbon black with a diameter of ≤ 100 nm.

Optionally, the fluorinated graphene quantum dots with a diameter of ≤10 nm are obtained by a fluorination reaction of graphene quantum dots with a diameter of ≤10 nm.

Optionally, the fluorination reaction includes: combining any one or at least two of single-layer graphene oxide with a plane size ≤ 10 μm, nano carbon black with a diameter ≤ 100 nm, or graphene quantum dots with a diameter ≤ 10 nm with fluorine. The chemical reagents are mixed, heated to carry out the fluorination reaction, and the carbon fluoride material is obtained.

Optionally, the fluorination reaction is carried out in a closed container, optionally a closed tetrafluoroethylene reactor.

Optionally, the fluorination reagent includes any one or a combination of at least two of hydrofluoric acid, trifluoroacetic acid, trifluoroacetic anhydride, xenon fluoride or fluorine gas, and hydrofluoric acid is optional.

The present application further selects hydrofluoric acid as the fluorination reagent. Since hydrofluoric acid has high reactivity, high-efficiency fluorination can be achieved, and at the same time, the cost is low, and the safety of the liquid-phase reaction is high.

Optionally, the fluorination reaction temperature is 120-230°C, such as 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, and the like.

Optionally, the time of the fluorination reaction is 12-30h, such as 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, 24h, 25h, 26h, 27h, 28h, 29h Wait.

Optionally, the fluorination reaction specifically includes the following steps:

(1) Add any one or at least two of graphene oxide with a plane size ≤ 10 μm, nano carbon black with a diameter ≤ 100 nm or graphene quantum dots with a diameter ≤ 10 nm and a fluorinating reagent into a closed tetrafluoroethylene reaction In the kettle, the fluorination reaction is carried out at 120-230° C. for 12-30 hours to obtain the carbon fluoride material.

Optionally, a polyimide with low dielectric, high light transmittance, low water absorption, high heat resistance and excellent mechanical properties is obtained by preparing the single-layer graphene oxide with a plane size of ≤10 μm by an improved Hummers method. composite material.

Optionally, the improved Hummers method comprises the steps:

(1) Add graphite and concentrated H ₂ SO ₄ in a glass bottle in an ice bath at 0-10 °C (optionally 0 °C), then add NaNO ₃ and KMnO ₄ under constant stirring and react for 0.5-2 h (optional) 1h);

(2) Keep in a water bath at 30-40°C (optional 35°C) for 0.5-2h (optional 1h);

(3) Add deionized water at 40-50°C (optionally 45°C), then treat with hydrogen peroxide, and wash the solid material obtained by centrifugation with hydrochloric acid and deionized water successively until the pH is adjusted to 7 to obtain graphene oxide aqueous solution;

(4) Take the graphene oxide aqueous solution, freeze it in liquid nitrogen, and then thoroughly dry it in a freeze dryer to obtain a single-layer graphene oxide aerogel powder with a plane size of ≤10 μm.

Optionally, the raw materials for preparing graphene quantum dots with a diameter of ≤10 nm include citric acid and/or glucose.

Optionally, the graphene quantum dots with a diameter less than or equal to 10 nm are prepared by a hydrothermal method.

Optionally, the hydrothermal method specifically includes the following steps:

Put citric acid and/or glucose into a beaker, heat directly to 150-250°C (optional 200°C) for 1.5-3h (optional 2h), then cool to room temperature, and use a dialysis bag (retained molecular weight: 1000Da ) was dialyzed overnight. Then, the solution is concentrated by rotary evaporation and dried to obtain graphene quantum dots with the diameter≤10nm.

Optionally, based on the mass of the polyimide matrix as 100%, the mass proportion of the fluorocarbon material is 0.1-5%, for example, 1.2%, 1.4%, 1.6%, 1.8%, 2% , 2.2%, 2.4%, 2.6%, 2.8%, 3%, 3.2%, 3.4%, 3.6%, 3.8%, 4%, 4.2%, 4.4%, 4.6%, 4.8%, etc.

The mass ratio of the optional fluorocarbon material in the present application is within this range, which can further improve the comprehensive performance of the composite material. If the ratio is too low, the dielectric constant of polyimide will not be reduced significantly, and the ratio will be too high. As a result, the processing difficulty is increased, and at the same time, agglomeration easily occurs, resulting in a decrease in optical transparency.

The second purpose of this application is to provide a preparation method of the polyimide composite material described in one of the purposes, and the preparation method comprises the following steps:

(1) fluorocarbon material, diamine monomer, dianhydride monomer and organic solvent are mixed and reacted to obtain fluorocarbon material and polyamic acid mixed solution;

(2) subjecting the mixed solution to an imidization reaction to obtain the polyimide composite material.

The present application adopts the method of in-situ polymerization to prepare the polyimide composite material, and the method is simple to operate.

Optionally, the diamine monomer includes any one or a combination of at least two of the following compounds:

Optionally, the dianhydride monomer includes any one or a combination of at least two of the following compounds:

Optionally, the molar ratio of the diamine monomer to the dianhydride monomer is (0.9-1):1, such as 0.91:1, 0.92:1, 0.93:1, 0.94:1, 0.95:1, 0.96: 1, 0.97:1, 0.98:1, 0.99:1, etc.

Optionally, the organic solvent includes N,N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), tetramethyl Any one or a combination of at least two of urea, dimethyl sulfoxide or hexamethylphosphoric triamide.

Optionally, step (1) specifically includes: adding a fluorocarbon material to an organic solvent, ultrasonicating, then adding a diamine monomer and a dianhydride monomer under nitrogen protection, and reacting to obtain a fluorocarbon material and a polymer. amic acid mixed solution.

Optionally, in step (1), the ultrasonic time is 20-50min, such as 22min, 24min, 26min, 28min, 30min, 32min, 34min, 36min, 38min, 40min, 42min, 44min, 46min, 48min, etc.

Optionally, in step (1), the dianhydride monomer is added in two batches.

Optionally, in step (1), the temperature of the reaction is 0-25°C, such as 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, 10°C ℃, 11℃, 12℃, 13℃, 14℃, 15℃, 16℃, 17℃, 18℃, 19℃, 20℃, 21℃, 22℃, 23℃, 24℃, etc.

Optionally, in step (1), the reaction time is 5-24h, such as 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h , 21h, 22h, 23h, 24h, etc.

Optionally, step (2) specifically includes: coating the mixed solution on a silicon wafer for film formation and soft baking, followed by imidization reaction to obtain the polyimide composite material.

Optionally, in step (2), the coating is realized by a spin coater.

Optionally, in step (2), the temperature of the soft bake is 60-100°C, such as 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C, and the like.

Optionally, in step (2), the soft baking is performed on a hot plate.

Optionally, in step (2), the temperature of the imidization reaction is 300-400°C, such as 310°C, 320°C, 330°C, 340°C, 350°C, 360°C, 370°C, 380°C, 390°C °C, etc.

Optionally, in step (2), the imidization reaction is carried out under nitrogen protection.

Optionally, the preparation method comprises the steps:

(1) Add the fluorinated carbon material to the organic solvent, sonicate for 20-50min, then add the diamine monomer under nitrogen protection, then add the dianhydride monomer twice, and react at 0-25°C for 5-24h , to obtain a mixed solution of carbon fluoride material and polyamic acid.

(2) Coating the mixed solution on a silicon wafer to form a film and performing soft baking on a hot plate at 60-100° C., and then introducing nitrogen gas and performing imidization at 300-400° C. to obtain the obtained The polyimide composite material.

In a specific embodiment of the present application, the preparation process of the polyimide composite material is shown in FIG. 1 .

The third objective of the present application is to provide an interlayer dielectric material, which contains the polyimide composite material described in one of the objectives.

The fourth purpose of the present application is to provide an application of the polyimide composite material according to the first purpose or the interlayer dielectric material according to the second purpose in packaging.

Optionally, the package includes a wafer-level fan-out package or a large board-level fan-out package.

Compared with the prior art, the present application has the following beneficial effects:

In the present application, the above-mentioned three specific sized carbon fluoride materials are introduced into the polyimide matrix. Within the size range defined in the present application, the dielectric constant can be effectively reduced, the hydrophobicity can be improved, and its optical transparency can be maintained. Compared with Fluorocarbon materials outside the specified size range can effectively improve the synthesis of polyimide, making it both low dielectric, high light transmittance, low water absorption, high heat resistance and excellent mechanical properties. Among them, the dielectric constant is 2.6-2.9, the contact angle is 86°-92°, the transmittance is 86-92%, the Young's modulus is 2-2.9GPa, the breaking stress is 190-220MPa, and the breaking elongation is 40-63%, 5% weight loss temperature is 566-580℃.

Description of drawings

FIG. 1 is a flow chart of the preparation of the polyimide composite material provided in a specific embodiment of the present application.

2 is a TEM image of fluorinated graphene in Example 1 of the present application.

FIG. 3 is a TEM image of the fluorinated quantum dots in Example 13 of the present application.

FIG. 4 is a TEM image of the fluorinated nanocarbon black in Example 14 of the present application.

5 is a graph of the dielectric properties of the fluorinated graphene/polyimide composite material in Example 1 of the present application.

6 is a graph of the dielectric properties of the fluorinated graphene quantum dot/polyimide composite material in Example 13 of the present application.

7 is a graph of the dielectric properties of the fluorinated nanocarbon black/polyimide composite material in Example 14 of the present application.

FIG. 8 is an optical transmittance diagram of the fluorinated graphene/polyimide composite material in Example 1 of the present application.

FIG. 9 is an optical transmittance diagram of the fluorinated graphene quantum dot/polyimide composite material in Example 13 of the present application.

FIG. 10 is an optical transmittance diagram of the fluorinated nanocarbon black/polyimide composite material in Example 14 of the present application.

FIG. 11 is a contact angle test diagram of the fluorinated graphene/polyimide composite material in Example 1 of the present application.

FIG. 12 is a contact angle test diagram of the fluorinated graphene quantum dot/polyimide composite material in Example 13 of the present application.

FIG. 13 is an optical contact angle test chart of the fluorinated nanocarbon black/polyimide composite material in Example 14 of the present application.

detailed description

In order to facilitate the understanding of the present application, the present application lists the following examples. It should be understood by those skilled in the art that the embodiments are only for helping the understanding of the present application, and should not be regarded as a specific limitation of the present application.

In the following examples and comparative examples, the plane dimensions or diameters of fluorinated graphene, fluorinated nanocarbon black and fluorinated graphene quantum dots are obtained by transmission electron microscopy (TEM) testing (take the average value), and the manufacturer of the transmission electron microscope It is Japan Electronics (JEOL), the instrument model is JEM-3200FS; the thickness of fluorinated graphene is measured by atomic force microscope (AFM), the manufacturer is Bruker, the instrument model is Dimension Icon; the fluorocarbon ratio is obtained by X-ray photoelectron spectroscopy The instrument (XPS) test was obtained from the manufacturer of Thermo Fisher in the United Kingdom, and the instrument model was ESCALAB 250Xi.

Example 1: Fluorinated graphene/polyimide composite

(1) Preparation of graphene oxide

First, 4 g of graphite and 120 mL of concentrated H ₂ SO ₄ were added to a glass bottle in an ice bath at 0 °C, then 2 g of NaNO ₃ and 20 g of KMnO ₄ were added under constant stirring and reacted for 1 h. Then, it was kept in a 35°C water bath for 1 hour. Finally, deionized water was added up to 500 mL at 45°C, treated with H ₂ O ₂ (30%), and the solid matter (graphene oxide) obtained by centrifugation (9500 rpm) was washed sequentially with 5% hydrochloric acid and deionized water until Adjust pH to 7.

The above graphene oxide is frozen by liquid nitrogen, and then thoroughly dried in a freeze dryer to obtain graphene oxide aerogel powder.

(2) Preparation of fluorinated graphene

Get 1g of above-mentioned graphene oxide aerogel powder and add it in the reaction kettle of 500mL of tetrafluoroethylene, add 5g of XeF ₂ and react at 200 ° C for 24 hours to obtain a plane size of 2 μm, a thickness of 1 nm, and a fluorocarbon ratio of 1:1 The monolayer of fluorinated graphene (TEM image is shown in Fig. 2).

(3) Preparation of polyimide composite materials

At room temperature, 0.02 g of fluorinated graphene and 36 g of nitrogen methyl pyrrolidone were added to a 100 mL three-necked flask, and it was completely dispersed uniformly by ultrasonic treatment for 30 minutes. Under the condition of nitrogen flow, add 2.00g of 4,4'-diaminodiphenyl ether to the reaction flask and stir well, then add 2.18g of pyromellitic anhydride in two batches, and react at 0°C for 12 hours Then, the fluorinated graphene/polyamic acid composite solution is obtained.

(4) The above fluorinated graphene/polyamic acid solution was spin-coated on the surface of a clean silicon wafer to form a film, baked at 80°C for 10 minutes, placed in a nitrogen oven, and subjected to imidization at 350°C to obtain polyimide Composite material (the content of fluorinated graphene is 0.5%, based on the mass of the polyimide matrix as 100%).

Example 2

The only difference from Example 1 is that, in step (3), the amount of fluorinated graphene added is 0.01 g, and the content of fluorinated graphene in the obtained composite material is 0.25%.

Example 3

The only difference from Example 1 is that, in step (3), the amount of fluorinated graphene added is 0.04 g, and the content of fluorinated graphene in the obtained composite material is 1%.

Example 4

The only difference from Example 1 is that, in step (3), the amount of fluorinated graphene added is 0.004 g, and the content of fluorinated graphene in the obtained composite material is 0.1%.

Example 5

The only difference from Example 1 is that, in step (3), the amount of fluorinated graphene added is 0.2 g, and the content of fluorinated graphene in the obtained composite material is 5%.

Example 6

The only difference from Example 1 is that in step (3), the amount of fluorinated graphene added is 0.002 g, and the content of fluorinated graphene in the obtained composite material is 0.05%.

Example 7

The only difference from Example 1 is that in step (3), the amount of fluorinated graphene added is 0.24 g, and the content of fluorinated graphene in the obtained composite material is 6%.

Example 8

The difference from Example 1 is that, in step (2), XeF ₂ is replaced with hydrofluoric acid of the same mass.

Example 9

The difference from Example 1 is that in step (2), the addition amount of XeF ₂ is 2 g, and the obtained fluorinated graphene has a fluorocarbon ratio of 0.5:1.

Example 10

The difference from Example 1 is that, in step (2), the addition amount of XeF ₂ is 6.5 g, and the obtained fluorinated graphene has a fluorocarbon ratio of 1.15:1.

Example 11

The difference from Example 1 is that, in step (2), the addition amount of XeF ₂ is 0.5 g, and the obtained fluorinated graphene has a fluorocarbon ratio of 0.1:1.

Example 12

The difference from Example 1 is that in step (2), the addition amount of XeF ₂ is 8 g, and the obtained fluorinated graphene has a fluorocarbon ratio of 1.5:1.

Example 13: Fluorinated graphene quantum dots/polyimide composites and films

(1) First, put 2g of citric acid into a 50mL beaker, heat directly to 200°C for about 2 hours, then cool to room temperature and dialyze overnight using a dialysis bag (retained molecular weight: 1000Da). The solution was then concentrated by rotary evaporation and dried at 80°C to obtain pale yellow crystals. Then put 1 g of graphene quantum dot powder and 5 _g of XeF into a sealed tetrafluoroethylene reaction kettle, and react at 200 ° C for 24 h to obtain fluorinated graphene quantum dots with an F/C ratio of 1.08 and a diameter of 3 nm. point (TEM image is shown in Fig. 3).

(2) at room temperature, in the three-necked flask of 100mL, add the nitrogen methyl pyrrolidone of 0.02g fluorinated graphene quantum dots and 36g, make it completely dispersed uniformly by ultrasonic treatment for 30 minutes. Under the condition of nitrogen flow, add 2.00g of 4,4'-diaminodiphenyl ether to the reaction flask and stir well, then add 2.18g of pyromellitic anhydride in two batches, and react at 0°C for 12 hours Then, the fluorinated graphene quantum dots/polyamic acid composite solution is obtained.

(3) The above fluorinated graphene quantum dots/polyamic acid solution was spin-coated on the surface of a clean silicon wafer to form a film, baked at 80°C for 10 minutes, placed in a nitrogen oven, and subjected to imidization at 350°C to obtain fluorination Graphene quantum dots/polyimide composite material (the content of fluorinated graphene quantum dots is 0.5%).

Example 14: Fluorinated Nanocarbon Black/Polyimide Composite

(1) First, put 1g of nano-carbon black and 5g of XeF into a sealed tetrafluoroethylene reactor, and react at ₂₀₀ °C for 24h to obtain a fluorinated fluoride with a F/C ratio of 1.12 and a diameter of about 50nm. Nano carbon black (TEM image is shown in Figure 4).

(2) At room temperature, add 0.02 g of fluorinated nano-carbon black and 36 g of nitrogen methyl pyrrolidone to a 100 mL three-necked flask, and perform ultrasonic treatment for 30 minutes to completely disperse uniformly. Under the condition of nitrogen flow, add 2.00g of 4,4'-diaminodiphenyl ether to the reaction flask and stir well, then add 2.18g of pyromellitic anhydride in two batches, and react at 0°C for 12 hours Then the fluorinated nano carbon black/polyamic acid composite solution is obtained.

(3) Spin coating the above fluorinated nano carbon black/polyamic acid solution on the surface of a clean silicon wafer to form a film, bake at 80°C for 10 min, put it in a nitrogen oven, and obtain fluorinated nanometers after imidization at 350°C Carbon black/polyimide composite film (the content of fluorinated nano carbon black is 0.5%).

Example 15: Fluorinated graphene/fluorinated graphene quantum dots/polyimide composite material

(1) at room temperature, add 0.01g fluorinated graphene (the preparation method is the same as in Example 1), 0.01g fluorinated graphene quantum dots (the preparation method is the same as in Example 13) and 36g of nitrous in a 100mL there-necked flask pyrrolidone, which was completely dispersed by ultrasonic treatment for 30 minutes. Under the condition of nitrogen flow, add 2.00g of 4,4'-diaminodiphenyl ether into the reaction flask and stir well, then add 2.18g of pyromellitic anhydride in two batches, and react at 0°C for 12 hours Then, the fluorinated graphene/fluorinated graphene quantum dots/polyamic acid composite solution is obtained.

(2) The above fluorinated graphene/fluorinated graphene quantum dots/polyamic acid solution was spin-coated on the surface of a clean silicon wafer to form a film, and after baking at 80°C for 10min, put it in a nitrogen oven, and pass through a sub-surface at 350°C. Amination obtains fluorinated graphene/fluorinated graphene quantum dots/polyimide composite material.

Example 16: Fluorinated graphene quantum dots/fluorinated nanocarbon black/polyimide composite material

(1) at room temperature, in the three-necked flask of 100mL, add 0.01g fluorinated graphene quantum dots (preparation method is the same as Example 13), 0.01g fluorinated nano carbon black (preparation method is the same as Example 14), and 36g of Nitrogen methyl pyrrolidone was fully dispersed by ultrasonication for 30 minutes. Under the condition of nitrogen flow, add 2.00g of 4,4'-diaminodiphenyl ether to the reaction flask and stir well, then add 2.18g of pyromellitic anhydride in two batches, and react at 0°C for 12 hours Then, a composite solution of fluorinated graphene quantum dots/fluorinated nano carbon black/polyamic acid is obtained.

(2) The above fluorinated graphene quantum dots/fluorinated nano carbon black/polyamic acid solution was spin-coated on the surface of a clean silicon wafer to form a film, baked at 80°C for 10min, placed in a nitrogen oven, and passed through a 350°C The fluorinated graphene quantum dots/fluorinated nanocarbon black/polyimide composite material is obtained by imidization.

Example 17: Fluorinated graphene/fluorinated graphene quantum dots/fluorinated nanocarbon black/polyimide composite material

(1) At room temperature, add 0.01g fluorinated graphene (the preparation method is the same as in Example 1), 0.01g fluorinated graphene quantum dots (the preparation method is the same as in Example 13), 0.01g fluorinated graphene in a 100mL three-necked flask Nano carbon black (the preparation method is the same as that of Example 14), and 36 g of nitrogen methyl pyrrolidone, were completely and uniformly dispersed by ultrasonic treatment for 30 minutes. Under the condition of nitrogen flow, add 2.00g of 4,4'-diaminodiphenyl ether to the reaction flask and stir well, then add 2.18g of pyromellitic anhydride in two batches, and react at 0°C for 12 hours Then, the fluorinated graphene/fluorinated graphene quantum dots/fluorinated nano carbon black/polyamic acid composite solution is obtained.

(2) The above fluorinated graphene quantum dots/fluorinated nano carbon black/polyamic acid solution was spin-coated on the surface of a clean silicon wafer to form a film, baked at 80°C for 10min, put into a nitrogen oven, and passed through a 350°C The fluorinated graphene/fluorinated graphene quantum dots/fluorinated nano carbon black/polyimide composite material is obtained by imidization.

Comparative Example 1

The difference from Example 1 is that in step (3), no fluorocarbon material is added.

Comparative Example 2

The difference with Embodiment 1 is that step (1) and step (2) are as follows:

(1) First, in a 0°C ice bath, add 4g graphite and 120mL concentrated H ₂ SO ₄ into a glass bottle, then add 2g NaNO ₃ and 20g KMnO ₄ under constant stirring and react for 1 h. Then, it was kept in a 35°C water bath for 1 hour. Finally, deionized water was added at 45°C until 500 mL, treated with H ₂ O ₂ (30%), and the supernatant obtained by centrifugation (1000 rpm) was washed sequentially with 5% hydrochloric acid and deionized water until the pH was adjusted to 7.

The above graphene oxide aqueous solution is frozen by liquid nitrogen, and then thoroughly dried in a freeze dryer to obtain graphene oxide aerogel powder.

(2) 1g above-mentioned graphene oxide aerogel powder is added in the reactor of the tetrafluoroethylene of 500mL, add 5g XeF ₂₄ hours at 200 ℃ of reaction, obtain plane size is 15 μm, thickness is 1nm, fluorocarbon ratio is 1 :1 single-layer fluorinated graphene.

Comparative Example 3

The difference with Embodiment 13 is that step (1) is as follows:

(1) First, put 2g of citric acid into a 50mL beaker, heat directly to 200°C for about 2 hours, then cool to room temperature, and dialyze overnight using a dialysis bag (retained molecular weight: 600Da). The solution was then concentrated by rotary evaporation and dried at 80°C to obtain pale yellow crystals. Then put 1g of graphene quantum dot powder and 5g of XeF into a sealed tetrafluoroethylene reactor, and react at ₂₀₀ °C for 24h to obtain fluorinated graphene quantum dots with an F/C ratio of 1.05 and a diameter of 20nm. point.

Comparative Example 4

The difference with Embodiment 14 is that step (1) is as follows:

(1) First, put 1g of nano _- carbon black and 5g of XeF into a sealed tetrafluoroethylene reactor, and react for 18h under the condition of 200°C to obtain a fluorinated nanometer with an F/C ratio of 1.10 and a diameter of 120nm. carbon black.

Performance Testing

(1) Dielectric constant test:

The dielectric properties of the material were tested with an impedance analyzer (Agilent 4294A). Before the test, gold was sprayed on both sides of the sample as electrodes, similar to a sandwich structure, and then the capacitance value was tested according to the formula:

Among them, C is the capacitance; d is the film thickness; A is the effective electrode area; ε ₀ is the vacuum dielectric constant.

(2) Contact angle test:

It was carried out on a contact angle measuring instrument with the model OCA20, and the volume of the droplet was 6uL. For comparison, the contact angle of all test samples was measured after the droplet was dropped for 10s.

(3) Transmittance test:

The light transmittance test was carried out on the UV-3600 UV-Vis spectrophotometer of SHIMADZU, Japan, and the test wavelength range was 200-800nm.

(4) Mechanical properties test

The polyimide film was cut into a stretched sample: length: 20 mm; width: 2 mm; thickness: 25 μm. Tensile tests were performed on a dynamic thermomechanical analyzer (DMA Q800). Test conditions: Under normal temperature environment, the tensile rate is 2N min ^-1 , and the maximum tensile force cannot exceed 18N.

(5) Thermogravimetric analysis test

Thermogravimetric analysis was performed on a TA SDTQ600 thermogravimetric analyzer. The heating conditions and process are as follows: in a nitrogen atmosphere of 100 mL min ^-1 , the heating temperature range is from 30°C to 800°C, and the heating rate is 10K min ^-1 . In this experiment, the weight of the tested material was controlled at about 7 mg, and the test obtained 5% weight loss temperature (T ₅ ).

The above test results are shown in Table 1.

Table 1

It can be seen from the data in Table 2 that the polyimide composite material provided by the present application has both lower dielectric constant, higher contact angle and transmittance. Compared with Example 1 without adding carbon fluoride material, the dielectric constant of Comparative Example 1 was significantly increased, and the contact angle was also significantly decreased; The size of the carbonized material is beyond the specific range of this application, and the comprehensive properties of the composite material are also significantly deteriorated.

By comparing Examples 1-7, it can be seen that when the mass proportion of the carbonized material is 0.1-5% (Example 1-5), it has the best comprehensive performance, and the addition amount is less than 0.1% (Example 6), and the medium The improvement of electric constant and contact angle is not obvious, the addition amount is higher than 5% (Example 7), the light transmittance is reduced, and the processing difficulty is increased.

Figures 5, 6 and 7 are graphs of the dielectric properties of Example 1, Example 13 and Example 14, respectively. The figures show that the relative dielectric constants are 2.88, 2.63 and 2.82 (1MHz), respectively.

Figures 8, 9 and 10 are the optical transmittance diagrams of Example 1, Example 13 and Example 14, respectively, which show that the optical transparency reaches 88%, 91% and 89% (550 nm).

Figure 11, Figure 12 and Figure 13 are the contact angle test charts of Example 1, Example 13 and Example 14, respectively. In the figures, the measured water contact angles reached 89°, 91°, and 90°, respectively.

The applicant declares that the present application illustrates the detailed method of the present application through the above-mentioned embodiments, but the present application is not limited to the above-mentioned detailed method, which does not mean that the present application must rely on the above-mentioned detailed method for implementation.

Claims

A polyimide composite material, comprising a polyimide matrix and a fluorinated carbon material distributed in the polyimide matrix;

The fluorinated carbon material includes any one or a combination of at least two of fluorinated graphene with a plane size of ≤10 μm, fluorinated nano-carbon black with a diameter of ≤100 nm, or fluorinated graphene quantum dots with a diameter of ≤10 nm.
The polyimide composite material according to claim 1, wherein, based on the mass of the polyimide matrix as 100%, the mass proportion of the carbon fluoride material is 0.1-5%.
The polyimide composite material according to claim 1 or 2, wherein the fluorocarbon ratios of the fluorinated graphene, fluorinated nanocarbon black and fluorinated graphene quantum dots are each independently (0.1-1.5) :1.
The polyimide composite material according to claim 3, wherein the fluorocarbon ratios of the fluorinated graphene, fluorinated nanocarbon black and fluorinated graphene quantum dots are each independently (0.5-1.15):1 .
The polyimide composite material according to any one of claims 1-4, wherein the fluorinated graphene is a single-layer fluorinated graphene;

Optionally, the thickness of the fluorinated graphene is less than or equal to 1 nm.
The polyimide composite material according to any one of claims 1-5, wherein the fluorinated graphene with a plane size ≤ 10 μm is obtained by a fluorination reaction of graphene oxide with a plane size ≤ 10 μm;

Optionally, the graphene oxide is single-layer graphene oxide;

Optionally, the graphene oxide with plane size≤10μm exists in the form of aerogel;

Optionally, the fluorinated nano carbon black with a diameter of ≤ 100 nm is obtained by a fluorination reaction of nano carbon black with a diameter of ≤ 100 nm;

Optionally, the fluorinated graphene quantum dots with diameter≤10nm are obtained by fluorination reaction of graphene quantum dots with diameter≤10nm;

Optionally, the fluorination reaction includes: fluorinating any one or at least two of graphene oxide with a plane size ≤ 10 μm, nano carbon black with a diameter ≤ 100 nm, or graphene quantum dots with a diameter ≤ 10 nm. The reagents are mixed and heated to carry out a fluorination reaction to obtain a carbon fluoride material;

Optionally, the fluorination reagent includes any one or a combination of at least two of hydrofluoric acid, trifluoroacetic acid, trifluoroacetic anhydride, xenon fluoride or fluorine gas, and optional hydrofluoric acid;

Optionally, the fluorination reaction temperature is 120-230°C;

Optionally, the time of the fluorination reaction is 12-30h.
A preparation method of a polyimide composite material according to any one of claims 1-6, wherein the preparation method comprises the steps of:

(1) fluorocarbon material, diamine monomer, dianhydride monomer and organic solvent are mixed and reacted to obtain fluorocarbon material and polyamic acid mixed solution;

(2) subjecting the mixed solution to an imidization reaction to obtain the polyimide composite material.
The preparation method according to claim 7, wherein the diamine monomer comprises any one or a combination of at least two of the following compounds:

Optionally, the dianhydride monomer includes any one or a combination of at least two of the following compounds:

Optionally, the molar ratio of the diamine monomer to the dianhydride monomer is (0.9-1): 1;

Optionally, the organic solvent includes N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N,N-dimethylformamide, tetramethylurea, dimethylsulfoxide or hexamethylene Any one or a combination of at least two of the methylphosphoric triamides.
The preparation method according to claim 7 or 8, wherein the step (1) specifically comprises: adding the fluorinated carbon material to an organic solvent, ultrasonicating, and then adding diamine monomer and dianhydride monomer under nitrogen protection , react to obtain the mixed solution of carbon fluoride material and polyamic acid;

Optionally, in step (1), the ultrasonic time is 20-50min;

Optionally, in step (1), the dianhydride monomer is added in two batches;

Optionally, in step (1), the temperature of the reaction is 0-25°C;

Optionally, in step (1), the time of the reaction is 5-24h;

Optionally, step (2) specifically includes: coating the mixed solution on a silicon wafer for film-forming and soft baking, followed by imidization to obtain the polyimide composite material;

Optionally, in step (2), the coating is realized by a spin coater;

Optionally, in step (2), the temperature of the soft bake is 60-100°C;

Optionally, in step (2), the soft roasting is performed on a hot plate;

Optionally, in step (2), the temperature of the imidization reaction is 300-400 °C;

Optionally, in step (2), the imidization reaction is carried out under nitrogen protection.
An interlayer dielectric material, wherein the interlayer dielectric material contains the polyimide composite material according to any one of claims 1-6.
An application of the polyimide composite material according to any one of claims 1-6 or the interlayer dielectric material according to claim 10 in packaging;

Optionally, the package includes a wafer-level fan-out package or a large board-level fan-out package.