High-thermal-stability low-warpage PCB aluminum base layer and preparation method thereof

Abstract

The invention relates to the technical field of multi-layer metal substrate production, in particular to a high-thermal-stability low-warpage PCB aluminum base layer and a preparation method thereof.The preparation method comprises the following steps that 1, an adhesive and a curing agent are mixed and dispersed for 20-40 min, then stirring is conducted for 20-30 min at the speed of 600-700 r / min, standing and exhaust treatment are conducted, and a glue solution is obtained; and (3) pretreating the surface of an aluminum plate, drying the aluminum plate, laminating the dried aluminum plate and the semi-cured adhesive film obtained in the step (2) on a roller press, laminating a copper foil on one side of the semi-cured adhesive film, and finally laminating the copper foil on a plate vulcameter to obtain the PCB aluminum base layer. The PCB aluminum base layer provided by the invention has better heat-conducting property, warping resistance and lower thermal expansion coefficient.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of multilayer metal substrate production, in particular to a high-thermal-stability low-warp PCB aluminum base layer and a preparation method thereof. BACKGROUND

[0002] As a core material in modern electronic industry, the development of PCB aluminum base layer is closely intertwined with the heat dissipation demand of high-power electronic equipment. Since the end of the 20th century, with the evolution of integrated circuits towards high density and high power, the problem of device overheating caused by the insufficient thermal conductivity of traditional FR-4 substrate has become increasingly prominent, which directly led to the technology of PCB aluminum substrate taking metal aluminum as the core heat dissipation carrier. This technology combines metal aluminum with high-thermal-conductivity insulating layer and copper foil circuit layer to build a sandwich structure of "copper foil-insulating layer-aluminum base", successfully solving the heat dissipation bottleneck of power devices and becoming a key supporting material in the fields of LED lighting, new energy vehicles, 5G base stations, etc. As a supporting structure, the aluminum plate needs to have excellent mechanical properties to adapt to the processing process such as punching and drilling, and maintain a stable thermal expansion coefficient to cope with high-temperature working environment. 4047 alloy, as a high-silicon aluminum alloy, is one of the main materials for the metal base layer of current PCB aluminum substrate, and its performance is significantly affected by the morphology and distribution of primary silicon phase and eutectic silicon phase. In the prior art, 4047 alloy is prepared by conventional process, but in actual application, it is found that the thermal expansion coefficient, especially in the Z direction (thickness direction), is higher than the standard value (≤23) at 200℃ and 300℃, respectively, leading to insufficient dimensional stability of the PCB board in high-temperature environment, affecting the overall reliability. In addition, in the cold and hot impact performance test, the warp value of the existing 4047 alloy plate after 500 cycles reaches 0.9mm, exceeding the standard requirement (less than 0.6mm), and the excessive warp is easy to cause the risk of delamination of the insulating medium layer and the copper foil or aluminum base combination interface under temperature change, thereby causing early failure of the device. These problems are mainly due to the insufficient spheroidization and uneven distribution of primary silicon phase and eutectic silicon phase in the alloy, which limits the improvement of the comprehensive performance of the alloy. In view of the above problems, the prior art with patent number CN115971977A discloses a "process method for preparing high-purity aluminum oxide substrate" which obtains a high-purity aluminum oxide polishing substrate with high size precision and low surface roughness by sequentially setting a plane edge frame, rough grinding, fine grinding and fine polishing process, which meets the mirror surface requirement, wherein the high-purity aluminum oxide ceramic substrate used before processing has a density of ≥3.95g / cm 3 , a thickness of δ±0.05mm, a warp of <0.2mm, and no cracks, pits and appearance defects such as defects, but this patent only improves the process and cannot enhance the thermal conductivity.

[0003] Therefore, there is an urgent need to develop a PCB aluminum substrate that can resist deformation and warping caused by differences in thermal expansion coefficients, while also having good thermal conductivity. Summary of the Invention

[0004] The purpose of this invention is to provide a high thermal stability and low warpage PCB aluminum substrate and its preparation method, so as to solve the problems of deformation and warpage caused by the large difference in thermal expansion coefficients between the aluminum plate and copper foil of the current PCB aluminum substrate, as well as the problem of poor thermal conductivity.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a method for preparing a high thermal stability and low warpage PCB aluminum substrate, comprising the following steps: (1) Mix and disperse the adhesive and curing agent for 20-40 min, then stir at 600-700 r / min for 20-30 min, let stand, and after degassing, obtain the adhesive solution; (2) The adhesive obtained in step (1) is coated onto the release film and air-dried. Finally, it is dried at 110~130℃ for 4~6 minutes and then debonded to obtain a semi-cured adhesive film. (3) The surface of the aluminum plate is pretreated and dried. After drying, it is pressed and coated with the semi-cured adhesive film obtained in step (2) on a roller press. Copper foil is attached to one side of the semi-cured adhesive film and finally pressed on a flat vulcanizer to obtain the PCB aluminum base layer.

[0006] This application uses a self-made adhesive and curing agent to mix to obtain a high-viscosity adhesive suitable for PCB substrates. Then, by semi-curing the adhesive, an adhesive film is obtained and bonded to the surface of aluminum plate and copper foil. After curing, the adhesive can not only firmly bond the aluminum plate and copper foil, but also the graphene-modified adhesive can give the PCB substrate thermal conductivity and heat resistance.

[0007] This application avoids the problem of warping caused by uneven dispersion of inorganic fillers in the resin system due to the introduction of a large amount of inorganic fillers in the conventional PCB substrate manufacturing process in order to improve its thermal conductivity.

[0008] In some embodiments, in step (1), the curing agent is a dicyandiamide curing agent and / or an imidazole curing agent.

[0009] Preferably, in step (1), the curing agent is a dicyandiamide curing agent or an imidazole curing agent.

[0010] More preferably, in step (1), the curing agent is dicyandiamide and 2-methylimidazole, with a mass ratio of 1:(0.12-0.15).

[0011] In some embodiments, in step (1), the mass ratio of the adhesive to the curing agent is 1:(0.02~0.04).

[0012] Preferably, in step (1), the mass ratio of the adhesive to the curing agent is 1:0.03.

[0013] In some embodiments, step (1) of the method for preparing the adhesive includes the following steps: S1. Melamine and diethanolamine were mixed and added to tetrahydrofuran. The mixture was stirred at room temperature for 1-2 hours. Then, N,N-diisopropylethylamine was added and the mixture was stirred at a constant temperature for 0.8-1.5 hours. The temperature was then raised to 80-85°C and stirred at a constant temperature for 15-17 hours. After the reaction, the mixture was concentrated and dried under reduced pressure, extracted, and subjected to column chromatography to obtain the compound shown in Formula I. (I); S2. Under an inert protective gas atmosphere, the compound shown in Formula I obtained in step S1, 2,5-furandicarboxylic acid, graphene and fumed silica are mixed and added to N,N-dimethylformamide, followed by the addition of xylene and n-butyl titanate. The mixture is heated to reflux and stirred at a constant temperature for 20-24 hours. After the reaction is completed, the mixture is concentrated and dried under reduced pressure to obtain a solid product. S3. The solid product obtained in step S2 is mixed with N,N-dimethylformamide, epichlorohydrin and tetrabutylammonium bromide are added, the temperature is raised to 100~120℃, and the mixture is stirred at a constant temperature for 10~12h. The mixture is concentrated under reduced pressure, and then sodium hydroxide aqueous solution is added and extracted to obtain modified epoxy resin. S4. Mix the diester, propylene glycol methyl ether acetate and N,N-dimethylformamide, add a high-temperature diluent, coupling agent and dispersant, stir for 0.8~1.5h, then add the modified epoxy resin obtained in step S3, continue stirring for 20~40min, finally add the polyurethane modified epoxy resin, stir for 20~40min to obtain the adhesive.

[0014] This application first uses cyanuric chloride and diethanolamine as raw materials to prepare a compound of formula I with a multi-hydroxyl structure. Then, the compound of formula I is reacted with 2,5-furandicarboxylic acid to obtain a hyperbranched polyester solid product. Subsequently, end-group modification is performed to introduce epoxy groups, resulting in a hyperbranched modified epoxy resin. Finally, the modified epoxy resin and polyurethane-modified epoxy resin are mixed as the main raw materials to obtain an adhesive. This adhesive has an intrinsically high viscosity and can anchor inorganic fillers in the adhesive structure through chemical bonds, reducing the problem of uneven dispersion caused by the physical mixing of inorganic fillers, which leads to a decrease in PCB substrate performance.

[0015] In some embodiments, in step S1, the molar ratio of cyanuric chloride to diethanolamine is 1:(3.2~3.5).

[0016] Preferably, in step S1, the molar ratio of cyanuric chloride and diethanolamine is 1:3.3.

[0017] In some embodiments, in step S2, the molar ratio of the compound represented by Formula I to 2,5-furandicarboxylic acid is 1:(0.9~1).

[0018] Preferably, in step S2, the molar ratio of the compound represented by Formula I to 2,5-furandicarboxylic acid is 1:0.9.

[0019] In some embodiments, in step S2, the mass ratio of the compound represented by Formula I, graphene, and fumed silica is 1:(0.05~0.15):(0.05~0.15).

[0020] Preferably, in step S2, the mass ratio of the compound represented by Formula I, graphene, and fumed silica is 1:0.1:0.1.

[0021] This application, by adjusting the mass ratio of the compound shown in Formula I, graphene, and fumed silica, can prevent the agglomeration of inorganic fillers due to excessive amounts, and also avoid the inorganic fillers competing with 2,5-furandicarboxylic acid for active sites, which would lead to a decrease in the final adhesive viscosity and a deterioration in the PCB substrate peel performance.

[0022] In some embodiments, in step S3, the amount of epichlorohydrin added is 1 to 1.4 times the mass of the solid product.

[0023] Preferably, in step S3, the amount of epichlorohydrin added is 1.2 times the mass of the solid product.

[0024] In some embodiments, in step S4, the mass ratio of the modified epoxy resin to the polyurethane modified epoxy resin is 1:(0.05~0.15).

[0025] Preferably, in step S4, the mass ratio of the modified epoxy resin to the polyurethane modified epoxy resin is 1:0.1.

[0026] In some embodiments, in step S4, the volume ratio of the diester, propylene glycol methyl ether acetate, and N,N-dimethylformamide is (0.3~0.6):(0.1~0.2):1.

[0027] Preferably, in step S4, the volume ratio of the diester, propylene glycol methyl ether acetate, and N,N-dimethylformamide is 0.5:0.15:1.

[0028] In some embodiments, in step S4, the mass of the high-temperature diluent accounts for 4 to 6% of the total mass of the high-temperature diluent, coupling agent, dispersant, modified epoxy resin, and polyurethane modified epoxy resin.

[0029] Preferably, in step S4, the mass of the high-temperature diluent accounts for 5% of the total mass of the high-temperature diluent, coupling agent, dispersant, modified epoxy resin, and polyurethane modified epoxy resin.

[0030] In some embodiments, in step S4, the amount of coupling agent added is 0.3 to 0.6% of the total mass of the modified epoxy resin and the polyurethane modified epoxy resin.

[0031] Preferably, in step S4, the amount of coupling agent added is 0.4% of the total mass of the modified epoxy resin and the polyurethane modified epoxy resin.

[0032] In some embodiments, in step S4, the amount of dispersant added is 0.2 to 0.5% of the total mass of the modified epoxy resin and the polyurethane modified epoxy resin.

[0033] Preferably, in step S4, the amount of dispersant added is 0.35% of the total mass of the modified epoxy resin and the polyurethane modified epoxy resin.

[0034] In some embodiments, in step S4, the amount added is 0.05 to 0.15% of the total mass of the modified epoxy resin and the polyurethane modified epoxy resin.

[0035] Preferably, in step S4, the amount added is 0.1% of the total mass of the modified epoxy resin and the polyurethane modified epoxy resin.

[0036] Another aspect of the present invention provides a high thermal stability and low warpage PCB aluminum substrate obtained by the above preparation method.

[0037] In some embodiments, the pretreatment steps in step (3) are as follows: cleaning the surface of the aluminum plate with deionized water, ethanol and KH-560 in sequence.

[0038] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses a self-made adhesive and a curing agent to mix to obtain a high viscosity adhesive suitable for PCB substrate. Then, the adhesive is semi-cured to obtain an adhesive film that is bonded to the surface of aluminum plate and copper foil. After curing, the adhesive can not only firmly bond the aluminum plate and copper foil, but also the high viscosity of the adhesive gives the PCB substrate a low coefficient of thermal expansion, thereby avoiding the problem of warping. It can also improve the thermal conductivity and heat resistance of the PCB substrate.

[0039] (2) The adhesive of the present invention can anchor inorganic fillers in the adhesive structure through chemical bonds, reducing the problem of uneven dispersion caused by physical mixing of inorganic fillers, thereby reducing the performance of PCB substrate.

[0040] (3) By adjusting the mass ratio of the compound, graphene and fumed silica shown in Formula I, this invention can prevent the agglomeration phenomenon that still occurs when there is too much inorganic filler, and avoid the inorganic filler competing with 2,5-furandicarboxylic acid for active sites, which would lead to a decrease in the final adhesive viscosity and a deterioration in the PCB substrate peel performance. Detailed Implementation

[0041] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0042] Unless otherwise specified, the post-processing operations described below, such as "reduced pressure drying", "mixing", "heating", "stirring", "granulation", "air drying", "air drying", and "fermentation", can be selected by those skilled in the art based on actual conditions, and are not further limited.

[0043] 690 epoxy diluent was purchased from Hubei Xinjiecheng Chemical Technology Co., Ltd.; dispersant was purchased from Hubei Changfu Chemical Co., Ltd.; polyurethane modified epoxy resin was purchased from Hubei Langbowan Biomedical Co., Ltd. Preparation Example 1 The method for preparing adhesives includes the following steps: S1. 0.1 mol cyanuric chloride and 0.3 mol diethanolamine were mixed and added to 500 ml tetrahydrofuran. The mixture was stirred at room temperature for 1 h, followed by the addition of 1 mol N,N-diisopropylethylamine and stirring at a constant temperature for another 1 h. The temperature was then raised to 83 °C and stirred at a constant temperature for 16 h. After the reaction, the mixture was concentrated and dried under reduced pressure, extracted (dichloromethane / deionized water), and subjected to column chromatography (methanol / dichloromethane system) to obtain the compound shown in Formula I. (I); 1 H NMR (400 MHz, DMSO-d6): δ = 4.69 (s, 6H), 3.34 (s, 24H); S2. Under a N2 atmosphere, 0.1 mol of the compound of formula I obtained in step S1 was mixed with 0.09 mol of 2,5-furandicarboxylic acid, 3.9 g of graphene and 3.9 g of fumed silica and added to 200 ml of N,N-dimethylformamide. Then, 400 ml of xylene and 4 ml of tetrabutyl titanate were added, the mixture was heated to reflux, stirred at a constant temperature for 22 h, and then concentrated and dried under reduced pressure to obtain a solid product. S3. Mix 50g of the solid product obtained in step S2 with 500ml of N,N-dimethylformamide, add 60g of epichlorohydrin and 7g of tetrabutylammonium bromide, heat to 110℃, stir at a constant temperature for 11h, concentrate under reduced pressure, then add 300ml of 20wt% sodium hydroxide aqueous solution, and extract (dichloromethane / deionized water) to obtain modified epoxy resin; S4. Mix 50 ml of diester, 15 ml of propylene glycol methyl ether acetate and 100 ml of N,N-dimethylformamide, add 3.7 g of 690 epoxy diluent, 0.2 g of KH-560 and 0.2 g of dispersant, stir for 1 h, then add 50 g of the modified epoxy resin obtained in step S3, continue stirring for 30 min, and finally add 5 g of polyurethane modified epoxy resin, stir for 30 min to obtain the adhesive.

[0044] Preparation Example 2 The preparation method of the adhesive is the same as that in Preparation Example 1, except that an equimolar amount of N-ethylethanolamine is used instead of diethanolamine.

[0045] Preparation Example 3 The preparation method of the adhesive is the same as that in Preparation Example 1, except that 2,5-furandicarboxylic acid is not added.

[0046] Preparation Example 4 The preparation method of the adhesive is the same as that in Preparation Example 1, except that the amount of graphene is 7g.

[0047] Example 1 A method for preparing a high thermal stability and low warpage PCB aluminum substrate includes the following steps: (1) Mix 50g of adhesive with 1.5g of curing agent and disperse for 30min, then stir at 650r / min for 25min, let stand, and after degassing, obtain the adhesive solution; (2) The adhesive obtained in step (1) is coated onto the release film and air-dried (thickness is 70μm). Finally, it is dried at 120℃ for 5min and then debonded to obtain a semi-cured adhesive film. (3) Clean the surface of the aluminum plate with deionized water, ethanol and KH-560 in sequence. After drying at 130°C for 20 min, press the semi-cured adhesive film obtained in step (2) onto the roller press (temperature set at 120°C, speed at 1 m / min). Finally press the copper foil on one side of the semi-cured adhesive film onto the flat vulcanizer (temperature set at 170°C) to obtain the PCB aluminum base layer.

[0048] The curing agent consists of dicyandiamide and 2-methylimidazole in a mass ratio of 1:0.13; the adhesive was prepared in Preparation Example 1.

[0049] Example 2 A method for preparing a high thermal stability and low warpage PCB aluminum substrate includes the following steps: (1) Mix 50g of adhesive with 1g of curing agent and disperse for 20min, then stir at 600r / min for 30min, let stand, and after degassing, obtain the adhesive solution; (2) The adhesive obtained in step (1) is coated onto the release film and air-dried (thickness is 70 μm). Finally, it is dried at 110°C for 6 min and then debonded to obtain a semi-cured adhesive film. (3) Clean the surface of the aluminum plate with deionized water, ethanol and KH-560 in sequence. After drying at 130°C for 20 min, press the semi-cured adhesive film obtained in step (2) onto the roller press (temperature set at 120°C, speed at 1 m / min). Finally press the copper foil on one side of the semi-cured adhesive film onto the flat vulcanizer (temperature set at 170°C) to obtain the PCB aluminum base layer.

[0050] The curing agent consists of dicyandiamide and 2-methylimidazole in a mass ratio of 1:0.12; the adhesive was prepared in Preparation Example 1.

[0051] Example 3 A method for preparing a high thermal stability and low warpage PCB aluminum substrate includes the following steps: (1) Mix 50g of adhesive with 2g of curing agent and disperse for 40min, then stir at 700r / min for 20min, let stand, and after degassing, obtain the adhesive solution; (2) The adhesive obtained in step (1) is coated onto the release film and air-dried (thickness is 70 μm). Finally, it is dried at 130°C for 4 min and then debonded to obtain a semi-cured adhesive film. (3) Clean the surface of the aluminum plate with deionized water, ethanol and KH-560 in sequence. After drying at 130°C for 20 min, press the semi-cured adhesive film obtained in step (2) onto the roller press (temperature set at 120°C, speed at 1 m / min). Finally press the copper foil on one side of the semi-cured adhesive film onto the flat vulcanizer (temperature set at 170°C) to obtain the PCB aluminum base layer.

[0052] The curing agent consists of dicyandiamide and 2-methylimidazole in a mass ratio of 1:0.15; the adhesive was prepared in Preparation Example 1.

[0053] Example 4 The preparation method of the high thermal stability and low warpage PCB aluminum substrate is the same as that in Example 1, except that the adhesive is prepared in Example 2.

[0054] Example 5 The preparation method of the high thermal stability and low warpage PCB aluminum substrate is the same as that in Example 1, except that the adhesive is prepared by Example 3.

[0055] Example 6 The preparation method of the high thermal stability and low warpage PCB aluminum substrate is the same as that in Example 1, except that the adhesive is prepared in Example 4.

[0056] Comparative Example 1 Comparative Example 2 The preparation method of the high thermal stability and low warpage PCB aluminum substrate is the same as that in Example 1, except that an equal mass of thermally conductive adhesive is used instead of an adhesive. The thermally conductive adhesive is prepared according to Example 1 in patent number CN119767563B.

[0057] Performance testing; (1) Thermal conductivity: Tested according to ASTM D5470, "Standard Test Method for Thermal Conductivity of Thermally Conductive Insulating Materials"; (2) Coefficient of thermal expansion: The coefficient of thermal expansion was tested using a single-rod vertical thermal expansion meter, with the test temperature ranging from 25℃ to 100℃; (3) Warpage: The test shall be conducted in accordance with GB-T4677.5-1984 "Test Method for Warpage of Printed Circuit Board".

[0058] Each embodiment and comparative example was tested according to the above method, and the results are shown in Table 1.

[0059] Table 1

[0060] According to the data in Table 1, the PCB aluminum substrates prepared in Examples 1-3 of this invention have good thermal conductivity, anti-warping ability, and low coefficient of thermal expansion. In Example 4, the use of equimolar N-ethylethanolamine instead of diethanolamine reduced the number of active sites, resulting in a decrease in the thermal conductivity of the PCB aluminum substrate and an increase in the coefficient of thermal expansion and warpage. In Example 5, the absence of 2,5-furandicarboxylic acid reduced the viscosity of the adhesive system, leading to a slight increase in the warpage of the PCB aluminum substrate. In Example 6, the change in the mass ratio of the compound shown in Formula I, graphene, and fumed silica increased the graphene content, which competed with 2,5-furandicarboxylic acid for active sites, resulting in a decrease in adhesive viscosity. Simultaneously, trace amounts of graphene agglomeration occurred, leading to an increase in the warpage of the PCB aluminum substrate, but a slight increase in thermal conductivity. In Comparative Example 1, the use of a thermally conductive adhesive prepared using existing technology instead of an adhesive resulted in similar thermal conductivity to Examples 1-4, but the lower viscosity of the adhesive compared to Examples 1-4 of this application led to an increase in the coefficient of thermal expansion of the PCB aluminum substrate.

[0061] (4) Peel strength: Tested according to IPC TM-650 2.4.9.1-1998 "Peel strength of flexible circuits"; The adhesive prepared in the preparation example and the thermally conductive adhesive prepared in Example 1 of Patent No. CN119767563B were tested according to method (4), and the results are shown in Table 2.

[0062] Table 2

[0063] According to the data in Table 2, the adhesive of Preparation Example 1 has good peel strength; Preparation Example 2, due to the use of equimolar N-ethylethanolamine instead of diethanolamine, resulted in a decrease in viscosity, thereby reducing peel strength; Preparation Example 3, due to the absence of 2,5-furandicarboxylic acid, resulted in a decrease in the viscosity of the adhesive system, thereby reducing peel strength; Preparation Example 4, due to the change in the mass ratio of the compound shown in Formula I, graphene, and fumed silica, increased the graphene content, which competed with 2,5-furandicarboxylic acid for active sites, leading to a decrease in adhesive viscosity and thus reducing the peel strength of the adhesive.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a high thermal stability and low warpage PCB aluminum substrate, characterized in that, Includes the following steps: (1) Mix and disperse the adhesive and curing agent for 20-40 min, then stir at 600-700 r / min for 20-30 min, let stand, and after degassing, obtain the adhesive solution; (2) The adhesive obtained in step (1) is coated onto the release film and air-dried. Finally, it is dried at 110~130℃ for 4~6 minutes and then debonded to obtain a semi-cured adhesive film. (3) The surface of the aluminum plate is pretreated and dried. After drying, it is pressed and coated with the semi-cured adhesive film obtained in step (2) on a roller press. Copper foil is attached to one side of the semi-cured adhesive film and finally pressed on a flat vulcanizer to obtain the PCB aluminum base layer.

2. The method for preparing a high thermal stability and low warpage PCB aluminum substrate according to claim 1, characterized in that, In step (1), the curing agent is a dicyandiamide curing agent and / or an imidazole curing agent.

3. The method for preparing a high thermal stability and low warpage PCB aluminum substrate according to claim 1, characterized in that, In step (1), the mass ratio of the adhesive to the curing agent is 1:(0.02~0.04).

4. The method for preparing a high thermal stability and low warpage PCB aluminum substrate according to claim 1, characterized in that, In step (1), the method for preparing the adhesive includes the following steps: S1. Melamine and diethanolamine were mixed and added to tetrahydrofuran. The mixture was stirred at room temperature for 1-2 hours. Then, N,N-diisopropylethylamine was added and the mixture was stirred at a constant temperature for 0.8-1.5 hours. The temperature was then raised to 80-85°C and stirred at a constant temperature for 15-17 hours. After the reaction, the mixture was concentrated and dried under reduced pressure, extracted, and subjected to column chromatography to obtain the compound shown in Formula I. （Ⅰ）； S2. Under an inert protective gas atmosphere, the compound shown in Formula I obtained in step S1, 2,5-furandicarboxylic acid, graphene and fumed silica are mixed and added to N,N-dimethylformamide, followed by the addition of xylene and n-butyl titanate. The mixture is heated to reflux and stirred at a constant temperature for 20-24 hours. After the reaction is completed, the mixture is concentrated and dried under reduced pressure to obtain a solid product. S3. The solid product obtained in step S2 is mixed with N,N-dimethylformamide, epichlorohydrin and tetrabutylammonium bromide are added, the temperature is raised to 100~120℃, and the mixture is stirred at a constant temperature for 10~12h. The mixture is concentrated under reduced pressure, and then sodium hydroxide aqueous solution is added and extracted to obtain modified epoxy resin. S4. Mix the diester, propylene glycol methyl ether acetate and N,N-dimethylformamide, add a high-temperature diluent, coupling agent and dispersant, stir for 0.8~1.5h, then add the modified epoxy resin obtained in step S3, continue stirring for 20~40min, finally add the polyurethane modified epoxy resin, stir for 20~40min to obtain the adhesive.

5. The method for preparing a high thermal stability and low warpage PCB aluminum substrate according to claim 4, characterized in that, In step S1, the molar ratio of cyanuric chloride and diethanolamine is 1:(3.2~3.5).

6. The method for preparing a high thermal stability and low warpage PCB aluminum substrate according to claim 4, characterized in that, In step S2, the molar ratio of the compound represented by Formula I to 2,5-furandicarboxylic acid is 1:(0.9~1).

7. The method for preparing a high thermal stability and low warpage PCB aluminum substrate according to claim 4, characterized in that, In step S2, the mass ratio of the compound represented by Formula I, graphene, and fumed silica is 1:(0.05~0.15):(0.05~0.15).

8. The method for preparing a high thermal stability and low warpage PCB aluminum substrate according to claim 4, characterized in that, In step S4, the mass ratio of the modified epoxy resin to the polyurethane modified epoxy resin is 1:(0.05~0.15).

9. The method for preparing a high thermal stability and low warpage PCB aluminum substrate according to claim 1, characterized in that, In step S4, the mass of the high-temperature diluent accounts for 4 to 6% of the total mass of the high-temperature diluent, coupling agent, dispersant, modified epoxy resin, and polyurethane modified epoxy resin.

10. A high thermal stability and low warpage PCB aluminum substrate obtained by the preparation method according to any one of claims 1 to 9.

Images