A composite thermally conductive pad and its preparation method

Abstract

This application provides a composite thermally conductive pad and its preparation method, belonging to the field of thermal conductivity technology. The preparation method of the composite thermally conductive pad of this application first involves applying a first adhesive to one side of a graphene pad, then allowing the first adhesive to penetrate into multiple gaps in the graphene pad through a static setting. Next, the first adhesive on the surface of the graphene pad is wiped off. Finally, the graphene pad and a metal sheet are laminated together. During the lamination process, a portion of the first adhesive in the multiple gaps of the graphene pad is squeezed out. This not only reduces the amount of first adhesive remaining in the composite thermally conductive pad but also allows most of the first adhesive to connect the gaps in the graphene pad and the metal sheet. This allows the multiple graphene sheets of the graphene pad near the end face of the metal sheet to directly contact the metal sheet, resulting in a composite thermally conductive pad that possesses both high strength and good thermal conductivity, increasing its reusability in chip testing.

Description

Technical Field

[0001] This application relates to the field of thermal conductivity technology, and more specifically, to a composite thermally conductive pad and its preparation method. Background Technology

[0002] Graphene is a material composed of carbon atoms arranged in sp... 2 Graphene is a single-layer two-dimensional honeycomb lattice structure material formed by hybrid orbitals. Due to its unique physical and chemical properties, graphene has received widespread attention in the field of materials science. Among its applications, graphene thermal pads, made from graphene's high thermal conductivity, are widely used in the thermal management of electronic devices. In existing technologies, graphene thermal pads are used in chip testing. However, during repeated use, due to their poor strength, graphene thermal pads are very prone to breakage during testing, and may leave residue on the chip surface. Therefore, improving the strength of graphene thermal pads is crucial for enhancing their reusability. Summary of the Invention

[0003] This application provides a composite thermally conductive pad and its preparation method, which has both high strength and good thermal conductivity.

[0004] The embodiments of this application are implemented as follows:

[0005] In a first aspect, this application provides a method for preparing a composite thermally conductive pad, comprising: preparing a graphene pad, applying a first adhesive to one side of the graphene pad with the side having the first adhesive facing upwards, allowing it to stand for at least 30 minutes, removing the first adhesive from the surface of the graphene pad, and pressing a metal sheet onto the side of the graphene pad with the first adhesive.

[0006] The graphene pad has a horizontal direction perpendicular to the thickness direction. The graphene pad includes multiple graphene sheets arranged sequentially in the horizontal direction, and there is a gap between any two adjacent graphene sheets.

[0007] The thickness of the metal sheet ranges from 1 μm to 1000 μm.

[0008] In the above technical solution, the composite thermal pad of this application is composed of a graphene pad and a metal sheet. The thickness of the metal sheet is only 1μm to 1000μm, which can significantly reduce the interfacial thermal resistance between the graphene pad and the aluminum sheet, reduce the thermal performance loss of the graphene pad, and improve the thermal conductivity of the composite thermal pad. The graphene pad includes multiple graphene sheets arranged sequentially in a horizontal direction. It not only has good thermal conductivity, but also has gaps between any two adjacent graphene sheets. The preparation method of the composite thermal pad of this application is as follows: First, a first adhesive is applied to one side of the graphene pad. Then, the first adhesive is allowed to penetrate into the multiple gaps in the graphene pad by standing. Next, the first adhesive on the surface of the graphene pad is wiped off. Finally, the graphene pad and the metal sheet are composited by pressing. During the pressing process, part of the first adhesive in the multiple gaps of the graphene pad is squeezed out, thereby achieving the purpose of bonding the metal sheet. The composite thermal pad fabrication method of this application employs a special bonding process that not only reduces the amount of first adhesive remaining in the composite thermal pad but also allows the first adhesive to be distributed in a dotted or blocky pattern. Most of this first adhesive connects the gaps between the graphene pad and the metal sheet, enabling multiple graphene sheets of the graphene pad to directly contact the end face of the metal sheet. This results in a composite thermal pad that possesses both high strength and good thermal conductivity, increasing its reusability in chip testing.

[0009] In some possible implementations, the thickness of the metal sheet is 5 μm to 50 μm.

[0010] In the above technical solution, by keeping the thickness of the metal sheet within the above range, it is beneficial to further reduce the interfacial thermal resistance between the graphene pad and the aluminum sheet, reduce the thermal performance loss of the graphene pad, and improve the thermal conductivity of the composite thermal pad.

[0011] In some possible implementations, the metal sheet includes an aluminum sheet, a copper sheet, a nickel sheet, or an indium sheet;

[0012] Optionally, the metal sheet is an aluminum sheet.

[0013] In the above technical solution, choosing aluminum sheet as the metal sheet can further improve the strength of the composite thermal pad, thereby increasing its reusability in chip testing.

[0014] In some possible implementations, the viscosity of the first adhesive is ≤100 mPa*S.

[0015] In the above technical solution, the first adhesive with a viscosity ≤100mpa*S has good permeability, which is beneficial for the first adhesive to penetrate into the gaps between the graphene sheets during the standing process.

[0016] In some possible implementations, the first adhesive is an organosilicone adhesive.

[0017] In some possible implementations, the method for removing the first adhesive from the surface of the graphene pad includes wiping it off with blotting paper.

[0018] In some possible implementations, the method of pressing the metal sheet with the graphene pad includes:

[0019] The metal sheet and the graphene gasket are pressed together using a pressing device. The pressing temperature is 50℃~150℃, the pressing pressure is 1MPa~100MPa, and the pressing time is 5min~20min.

[0020] In some possible implementations, the thickness of the graphene pad is 0.1 mm to 5 mm;

[0021] Optionally, the thickness of the graphene pad is 0.1 mm to 1 mm.

[0022] In some possible implementations, two adjacent graphene sheets are bonded together with a second adhesive, which is distributed in an island-like pattern.

[0023] In the above technical solution, the second adhesive, which is distributed in an island-like pattern, can not only bond multiple graphene sheets together, but also does not have a significant impact on the overall thermal conductivity of the graphene pad.

[0024] In a second aspect, this application provides a composite thermally conductive pad, which is prepared according to the method for preparing the composite thermally conductive pad in the above embodiments.

[0025] In the above technical solution, the composite thermal pad of this application has both high strength and good thermal conductivity, which increases the number of times it can be reused in chip testing. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the structure of the composite thermal pad according to an embodiment of this application;

[0028] Figure 2 for Figure 1 Enlarged view of region A;

[0029] Figure 3 for Figure 1A magnified view of region B.

[0030] Icons: 10-Composite thermal conductive pad; 100-Graphene pad; 110-Graphene sheet; 120-Second adhesive block; 200-Adhesive layer; 210-First adhesive block; 300-Metal sheet. Detailed Implementation

[0031] The embodiments of this application will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of this application. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0032] Metallic materials are also commonly used thermally conductive materials, possessing excellent thermal conductivity and processability. This application proposes that combining metallic materials with graphene pads to form composite thermally conductive pads could potentially improve the mechanical strength of graphene pads and increase their reusability in chip testing.

[0033] However, due to the different materials of the metal material and the presence of a composite interface, there is a large interfacial thermal resistance between the metal material and the graphene pad, resulting in a significant loss of thermal performance of the graphene pad and poor thermal conductivity of the composite thermal pad.

[0034] Based on this, this application provides a method for preparing a composite thermally conductive pad, which includes the following steps:

[0035] S1. Prepare graphene pads

[0036] The graphene pad has a horizontal direction perpendicular to the thickness direction. The graphene pad includes multiple graphene sheets arranged sequentially in the horizontal direction, and there is a gap between any two adjacent graphene sheets.

[0037] The thickness of the graphene gasket is 0.1mm to 5mm.

[0038] As an example, the thickness of the graphene pad can be 0.1mm, 0.2mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm or 5mm.

[0039] Optionally, the thickness of the graphene pad is 0.1 mm to 1 mm.

[0040] Adjacent graphene sheets are bonded together using a second adhesive, which is distributed in an island-like pattern. This island-like distribution of the second adhesive not only bonds multiple graphene sheets together but also does not significantly affect the overall thermal conductivity of the graphene pad.

[0041] The graphene gasket in this application can be purchased commercially or made in-house. This application provides a method for preparing a graphene gasket, including the following steps:

[0042] A dotted layer of acrylic resin adhesive is sprayed onto the first graphene film. Then, the second graphene film is aligned and placed on top of the first graphene film. Another layer of acrylic resin adhesive is then applied to the second graphene film. The third graphene film is then stacked on top of the first graphene film, and this process is repeated until the target height is reached to obtain a graphene film block. The graphene film block is then sliced ​​along the stacking direction of the graphene films using laser cutting to obtain graphene pads.

[0043] S2, Apply the first adhesive

[0044] Place the graphene pad under the spraying equipment, spray the first adhesive onto one surface of the graphene pad with the side with the first adhesive facing upwards, let it stand for at least 30 minutes, and then remove the first adhesive from the surface of the graphene pad.

[0045] Optionally, the viscosity of the first adhesive is ≤100mpa*S. The first adhesive with a viscosity ≤100mpa*S has good permeability, which is beneficial for the first adhesive to penetrate into the gaps between the graphene sheets during the standing process.

[0046] Optionally, the first adhesive is an organosilicon adhesive.

[0047] As an example, the settling time can be 30 min, 60 min, 90 min, 120 min, 150 min, or 180 min.

[0048] Alternatively, methods for removing the first adhesive from the surface of the graphene pad include wiping it off with blotting paper.

[0049] S3, Pressing

[0050] Prepare a metal sheet. Place the graphene pad and the metal sheet on a clean workbench. Then, using a high-precision positioning device, overlap the graphene pad and the metal sheet so that the side of the graphene pad that was coated with the first adhesive contacts the metal sheet. Next, align them so that they are completely aligned in the length and width directions. Finally, use a pressing device to apply a certain pressure between the graphene pad and the metal sheet to make them tightly bonded, thus obtaining a composite thermal conductive pad.

[0051] The thickness of the metal sheet ranges from 1 μm to 1000 μm.

[0052] As an example, the thickness of the metal sheet can be 1μm, 2μm, 5μm, 10μm, 50μm, 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm or 1000μm.

[0053] Optionally, the thickness of the metal sheet is 5μm to 50μm.

[0054] Optionally, by keeping the thickness of the metal sheet within the aforementioned range, it is beneficial to further reduce the interfacial thermal resistance between the graphene pad and the aluminum sheet, reduce the thermal performance loss of the graphene pad, and improve the thermal conductivity of the composite thermal pad.

[0055] Metal sheets include aluminum sheets, copper sheets, nickel sheets, or indium sheets.

[0056] Optionally, the metal sheet is an aluminum sheet.

[0057] Choosing aluminum sheet as the metal sheet can further improve the strength of the composite thermal pad, thereby increasing its reusability in chip testing.

[0058] Optionally, the pressing temperature is 50℃~150℃, the pressing pressure is 1MPa~100MPa, and the pressing time is 5min~20min.

[0059] As an example, the pressing temperature can be 50℃, 60℃, 70℃, 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃ or 150℃, the pressing pressure can be 1MPa, 2MPa, 5MPa, 10MPa, 20MPa, 30MPa, 40MPa, 50MPa, 60MPa, 70MPa, 80MPa, 90MPa or 100MPa, and the pressing time can be 5min, 10min, 15min or 20min.

[0060] The composite thermal pad of this application is composed of a graphene pad and a metal sheet. The thickness of the metal sheet is only 1μm to 1000μm, which can significantly reduce the interfacial thermal resistance between the graphene pad and the aluminum sheet, reduce the thermal performance loss of the graphene pad, and improve the thermal conductivity of the composite thermal pad. The graphene pad includes multiple graphene sheets arranged sequentially in a horizontal direction. It not only has good thermal conductivity, but also has gaps between any two adjacent graphene sheets. The preparation method of the composite thermal pad of this application is as follows: First, a first adhesive is applied to one side of the graphene pad. Then, the first adhesive is allowed to penetrate into the multiple gaps of the graphene pad by standing. Next, the first adhesive on the surface of the graphene pad is wiped off. Finally, the graphene pad and the metal sheet are composited by pressing. During the pressing process, part of the first adhesive in the multiple gaps of the graphene pad is squeezed out, thereby achieving the purpose of bonding the metal sheet. The composite thermal pad preparation method of this application employs a special bonding process that not only reduces the amount of first adhesive remaining in the composite thermal pad, but also allows the first adhesive to be distributed in a dotted or blocky pattern. Most of this first adhesive connects the gaps between the graphene pad and the metal sheet, enabling multiple graphene sheets near the end face of the metal sheet to directly contact the metal sheet. This results in a composite thermal pad that possesses both high strength and good thermal conductivity, increasing its reusability in chip testing, reducing the testing cost of chips or power devices, and improving the problem of graphene pad residue at the chip testing end.

[0061] The composite thermally conductive pad of this application has wide applications in fields such as heat dissipation management of electronic devices, material recycling, and the research and development of high-performance thermally conductive materials. Firstly, in the field of heat dissipation management of electronic devices, the composite thermally conductive pad of this application can significantly improve reusability, reduce interfacial thermal resistance, and enhance thermal conductivity. This is of great significance for solving the common heat dissipation problems in current electronic devices. Furthermore, as electronic devices develop towards high performance, miniaturization, and integration, heat dissipation problems are becoming increasingly prominent, making the application prospects of this technical solution broad. Secondly, in the field of material recycling, the composite thermally conductive pad of this application features a detachable design, enabling the reuse of graphene pads, reducing resource waste, and lowering production costs. This is of great significance for promoting the development of material recycling technology and achieving sustainable development. With increasing environmental awareness and the growing severity of resource shortages, the demand for material recycling technology is increasing, making the application prospects of this technical solution broad. Finally, in the field of high-performance thermal conductive material research and development, the composite thermal conductive pad of this application can fully utilize the thermal conductivity of graphene and improve thermal conductivity efficiency. This is of great significance for developing higher-performance thermal conductive materials and meeting the heat dissipation requirements of high-end electronic devices. With the development of high-end electronic devices, the demand for high-performance thermal conductive materials is increasing, and the application prospects of this technical solution are broad. In summary, the composite thermal conductive pad of this application has broad application prospects and large market demand, and is expected to play an important role in fields such as heat dissipation management of electronic devices, material reuse, and the research and development of high-performance thermal conductive materials.

[0062] This application also provides a composite thermally conductive pad, which is prepared according to the method for preparing the composite thermally conductive pad in the above embodiments.

[0063] Please see Figure 1 The composite thermal pad 10 includes a graphene pad 100, an adhesive layer 200, and a metal sheet 300 arranged sequentially along the thickness direction.

[0064] Please refer to Figure 2 The graphene pad 100 is a thermally conductive pad made from a raw material including graphene. It has a horizontal direction perpendicular to the thickness direction. The graphene pad 100 includes a plurality of graphene sheets 110 arranged sequentially in the horizontal direction, and there is a gap between any two adjacent graphene sheets 110.

[0065] Optionally, two adjacent graphene sheets 110 are bonded together by a plurality of second adhesive blocks 120, and the plurality of second adhesive blocks 120 are distributed in an island-like manner.

[0066] Please see Figure 1 and 3 The adhesive layer 200 is a layered structure that connects the graphene pad 100 and the metal sheet 300, and its thickness is ≤5μm.

[0067] Optionally, the adhesive layer 200 includes a plurality of first adhesive blocks 210 distributed in an island-like manner. The plurality of first adhesive blocks 210 distributed in an island-like manner are used to connect the graphene pad 100 and the metal sheet 300. This allows many areas of the graphene sheets 110 of the graphene pad 100 near the end face of the metal sheet 300 that do not have first adhesive blocks 210 to directly contact the metal sheet 300. As a result, the composite thermal pad 10 has both high strength and good thermal conductivity, and improves its reusability in chip testing.

[0068] Optionally, the first adhesive block 210 includes an organosilicon adhesive.

[0069] Metal sheet 300 is a sheet-like structure made of metal material with a thickness of 1μm to 1000μm.

[0070] Metal sheet 300 includes aluminum sheet, copper sheet, nickel sheet or indium sheet.

[0071] Optionally, the metal sheet 300 is an aluminum sheet.

[0072] Please see Figure 3 The graphene sheet 110 includes a large surface close to the adjacent graphene sheet 110. One end of the first adhesive block 210 is connected to the metal sheet 300, and the other end is connected to the large surface of the graphene sheet 110 and / or the second adhesive block 120.

[0073] The two ends of the first adhesive block 210 are used to connect the large surfaces of the metal sheet 300 and the graphene sheet 110 and / or the second adhesive block 120, respectively, so that the multiple graphene sheets 110 of the graphene pad 100 can directly contact the end face of the metal sheet 300 near the metal sheet 300, thereby making the composite thermal pad 10 have both high strength and good thermal conductivity, and increasing its reusability in chip testing.

[0074] The following describes in further detail a composite thermally conductive pad and its preparation method according to the present application, with reference to embodiments.

[0075] Example 1

[0076] This application provides a composite thermally conductive pad and its preparation method, which includes the following steps:

[0077] S1. Prepare graphene pads

[0078] A dotted acrylic resin adhesive is sprayed onto the first graphene film. Then, the second graphene film is aligned and placed on the first graphene film. Another layer of acrylic resin adhesive is then applied to the second graphene film. The third graphene film is then stacked on top of this, and this process is repeated until the target height is reached to obtain a graphene film block. The graphene film block is then sliced ​​along the stacking direction of the graphene films using laser cutting to obtain graphene pads with a thickness of 0.3 mm.

[0079] The graphene pad has a horizontal direction perpendicular to the thickness direction. The graphene pad includes multiple graphene sheets arranged sequentially in the horizontal direction, and there is a gap between any two adjacent graphene sheets.

[0080] S2, Set the silicone adhesive

[0081] The prepared graphene gasket was placed under the spraying equipment. The spraying equipment was used to spray an organosilicon adhesive with a viscosity ≤100mpa*S onto one surface of the graphene gasket, with the side with the organosilicon adhesive facing upwards. After standing for 60 minutes, the organosilicon adhesive on the surface of the graphene gasket was wiped off with oil-absorbing paper.

[0082] S3, Pressing

[0083] Prepare an aluminum sheet with a thickness of 10μm. Place the graphene pad and the aluminum sheet on a clean workbench. Then, using a high-precision positioning device, overlap the graphene pad and the aluminum sheet so that the side of the graphene pad with the silicone adhesive is in contact with the aluminum sheet. Next, align them so that they are completely aligned in the length and width directions. Finally, use a pressing device to apply a certain pressure between the graphene pad and the aluminum sheet to make them tightly bonded, thus obtaining a composite thermal conductive pad.

[0084] Example 2

[0085] This application provides a composite thermally conductive pad and its preparation method, which includes the following steps:

[0086] S1. Prepare graphene pads

[0087] A dotted acrylic resin adhesive is sprayed onto the first graphene film. Then, the second graphene film is aligned and placed on the first graphene film. Another layer of acrylic resin adhesive is then applied to the second graphene film. The third graphene film is then stacked on top of this, and this process is repeated until the target height is reached to obtain a graphene film block. The graphene film block is then sliced ​​along the stacking direction of the graphene films using laser cutting to obtain graphene pads with a thickness of 0.5 mm.

[0088] The graphene pad has a horizontal direction perpendicular to the thickness direction. The graphene pad includes multiple graphene sheets arranged sequentially in the horizontal direction, and there is a gap between any two adjacent graphene sheets.

[0089] S2, Set the silicone adhesive

[0090] The prepared graphene gasket was placed under the spraying equipment. The spraying equipment was used to spray an organosilicon adhesive with a viscosity ≤100mpa*S onto one surface of the graphene gasket, with the side with the organosilicon adhesive facing upwards. After standing for 60 minutes, the organosilicon adhesive on the surface of the graphene gasket was wiped off with oil-absorbing paper.

[0091] S3, Pressing

[0092] Prepare an aluminum sheet with a thickness of 25μm. Place the graphene pad and the aluminum sheet on a clean workbench. Then, using a high-precision positioning device, overlap the graphene pad and the aluminum sheet so that the side of the graphene pad with the silicone adhesive is in contact with the aluminum sheet. Next, align them so that they are completely aligned in the length and width directions. Finally, use a pressing device to apply a certain pressure between the graphene pad and the aluminum sheet to make them tightly bonded, thus obtaining a composite thermal conductive pad.

[0093] Example 3

[0094] This application provides a composite thermally conductive pad and its preparation method, which includes the following steps:

[0095] S1. Prepare graphene pads

[0096] A dotted acrylic resin adhesive is sprayed onto the first graphene film. Then, the second graphene film is aligned and placed on the first graphene film. Another layer of acrylic resin adhesive is then applied to the second graphene film. The third graphene film is then stacked on top of this, and this process is repeated until the target height is reached to obtain a graphene film block. The graphene film block is then sliced ​​along the direction of the graphene film stacking using laser cutting to obtain a graphene pad with a thickness of 1 mm.

[0097] The graphene pad has a horizontal direction perpendicular to the thickness direction. The graphene pad includes multiple graphene sheets arranged sequentially in the horizontal direction, and there is a gap between any two adjacent graphene sheets.

[0098] S2, Set the silicone adhesive

[0099] The prepared graphene gasket was placed under the spraying equipment. The spraying equipment was used to spray an organosilicon adhesive with a viscosity ≤100mpa*S onto one surface of the graphene gasket, with the side with the organosilicon adhesive facing upwards. After standing for 60 minutes, the organosilicon adhesive on the surface of the graphene gasket was wiped off with oil-absorbing paper.

[0100] S3, Pressing

[0101] Prepare an aluminum sheet with a thickness of 100μm. Place the graphene pad and the aluminum sheet on a clean workbench. Then, using a high-precision positioning device, overlap the graphene pad and the aluminum sheet so that the side of the graphene pad with the silicone adhesive is in contact with the aluminum sheet. Next, align them so that they are completely aligned in the length and width directions. Finally, use a pressing device to apply a certain pressure between the graphene pad and the aluminum sheet to make them tightly bonded, thus obtaining a composite thermal conductive pad.

[0102] Example 4

[0103] This application provides a composite thermally conductive pad and its preparation method, which is based on Example 2, except that the thickness of the aluminum sheet is changed to 1 μm, while other aspects remain unchanged.

[0104] Example 5

[0105] This application provides a composite thermal conductive pad and its preparation method, which is based on Example 2, except that the thickness of the aluminum sheet is changed to 5 μm, while other aspects remain unchanged.

[0106] Example 6

[0107] This application provides a composite thermal conductive pad and its preparation method, which is based on Example 2, except that the thickness of the aluminum sheet is changed to 50 μm, while other aspects remain unchanged.

[0108] Example 7

[0109] This application provides a composite thermally conductive pad and its preparation method, which is based on Example 2, except that the thickness of the aluminum sheet is changed to 1000 μm, while other aspects remain unchanged.

[0110] Example 8

[0111] This application provides a composite thermally conductive pad and its preparation method, which is based on Example 2, except that the thickness of the graphene pad is changed to 0.1 μm, while other aspects remain unchanged.

[0112] Example 9

[0113] This application provides a composite thermally conductive pad and its preparation method, which is based on Example 2, except that the thickness of the graphene pad is changed to 5 μm, while other aspects remain unchanged.

[0114] Example 10

[0115] This application provides a composite thermal pad and its preparation method, which is based on Example 2, except that the aluminum sheet is replaced with an indium sheet, while the others remain unchanged.

[0116] Comparative Example 1

[0117] This application provides a comparative example of a thermally conductive pad and its preparation method, which includes the following steps:

[0118] A dotted acrylic resin adhesive is sprayed onto the first graphene film. Then, the second graphene film is aligned and placed on the first graphene film. Another layer of acrylic resin adhesive is then applied to the second graphene film. The third graphene film is then stacked on top of this, and this process is repeated until the target height is reached to obtain a graphene film block. The graphene film block is then sliced ​​along the stacking direction of the graphene films using laser cutting to obtain graphene pads with a thickness of 0.5 mm.

[0119] Comparative Example 2

[0120] This application provides a comparative example of a composite thermally conductive pad and its preparation method, which includes the following steps:

[0121] S1. Prepare graphene pads

[0122] A dotted acrylic resin adhesive is sprayed onto the first graphene film. Then, the second graphene film is aligned and placed on the first graphene film. Another layer of acrylic resin adhesive is then applied to the second graphene film. The third graphene film is then stacked on top of this, and this process is repeated until the target height is reached to obtain a graphene film block. The graphene film block is then sliced ​​along the stacking direction of the graphene films using laser cutting to obtain graphene pads with a thickness of 0.5 mm.

[0123] The graphene pad has a horizontal direction perpendicular to the thickness direction. The graphene pad includes multiple graphene sheets arranged sequentially in the horizontal direction, and there is a gap between any two adjacent graphene sheets.

[0124] S2, Set the silicone adhesive

[0125] The prepared graphene pad is placed under a spraying device, and an organosilicon adhesive with a viscosity ≤100mpa*S is sprayed onto one surface of the graphene pad using the spraying device.

[0126] S3, Pressing

[0127] Prepare an aluminum sheet with a thickness of 25μm. Place the graphene pad and the aluminum sheet on a clean workbench. Then, using a high-precision positioning device, overlap the graphene pad and the aluminum sheet so that the side of the graphene pad with the silicone adhesive is in contact with the aluminum sheet. Next, align them so that they are completely aligned in the length and width directions. Finally, use a pressing device to apply a certain pressure between the graphene pad and the aluminum sheet to make them tightly bonded, thus obtaining a composite thermal conductive pad.

[0128] Comparative Example 3

[0129] This application provides a comparative example of a composite thermally conductive pad and its preparation method, which is based on Example 2, except that the thickness of the aluminum sheet is changed to 2000 μm, while other aspects remain unchanged.

[0130] The parameters of the composite thermal pads of Examples 1-10, Comparative Examples 2-3, and the thermal pad of Comparative Example 1 are shown in Table 1:

[0131] Table 1. Parameters of the composite thermal pads in Examples 1-10, Comparative Examples 2-3, and the thermal pad in Comparative Example 1.

[0132]

[0133]

[0134] Experimental Example 1

[0135] The composite thermal pads prepared in Examples 1-10 and Comparative Examples 2-3, and the thermal pad prepared in Comparative Example 1 were used to measure the thermal resistance of the graphene pad bare material, the overall thermal resistance, and the number of times it could be reused in chip testing. The results are shown in Table 2.

[0136] The testing method is as follows:

[0137] 1. Thermal resistance test

[0138] The graphene gasket bare material or the composite metal gasket was cut into 25.4*25.4mm pieces and tested using a LONGWIN-9389 device from Taiwan, China, with the test pressure set to 40psi.

[0139] 2. Repeat usage test

[0140] The graphene thermal pad with a surface-composite metal sheet was cut into 25.4*25.4mm sizes and compressed using an INSTRON 68 million tensile tester. The compression pressure was set to 60psi, and the holding time was 30 minutes. Then the pressure head was raised, and the compression was repeated 10 times. The sample was removed, and the damage was checked. It was then placed in a LONGWIN-9389 thermal resistance tester from Taiwan, China. When the thermal resistance exceeded the initial thermal resistance by 15% or cracks appeared on the surface, the number of uses was recorded.

[0141] Table 2 shows the performance of the composite thermal pads in Examples 1-10, Comparative Examples 2-3, and the thermal pad in Comparative Example 1.

[0142]

[0143]

[0144] As shown in Examples 1-9, when the metal sheet is made of aluminum with a thickness of 1μm to 1000μm, the graphene pad has a thickness of 0.1mm to 5mm, and the adhesive layer thickness is ≤5μm, the overall thermal resistance of the resulting composite thermally conductive pad is 0.076℃cm. 2 / W~3.4℃cm 2 / W, which can be reused 70 to 1560 times in chip testing;

[0145] As shown in Example 10, when the metal sheet is made of indium, has a thickness of 25 μm, the graphene pad has a thickness of 0.5 mm, and the adhesive layer thickness is ≤5 μm, the overall thermal resistance of the resulting composite thermal pad is 0.131 °C / cm². 2 / W, which can be reused 530 times in chip testing;

[0146] A comparison of Comparative Example 1 and Example 2 shows that Comparative Example 1 only has a graphene pad and no aluminum sheet; the overall thermal resistance of the thermally conductive pad is 0.068 °C / cm. 2 / W, the number of times it can be reused in chip testing is only 30 times, which is far less than the number of times the composite thermal pad of Example 2 with aluminum sheet can be reused in chip testing;

[0147] A comparison between Comparative Example 2 and Example 2 shows that the adhesive layer thickness of Comparative Example 2 is 10 μm to 20 μm, and the overall thermal resistance of the resulting composite thermally conductive pad is 0.174 °C / cm. 2 / W, which is higher than the overall thermal resistance of the composite thermal pad in Example 2;

[0148] A comparison between Comparative Example 3 and Example 2 shows that the metal sheet thickness of Comparative Example 3 is 2000 μm, and the overall thermal resistance of the resulting composite thermal pad is as high as 5.6 °C / cm. 2 / W, which is far higher than the overall thermal resistance of the composite thermal pad in Example 2.

[0149] The above description is merely a specific embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing a composite thermally conductive pad, characterized in that, The method for preparing the thermal pad includes: preparing a graphene pad, applying a first adhesive to one side of the graphene pad with the side having the first adhesive facing upwards, allowing it to stand for at least 30 minutes, removing the first adhesive from the surface of the graphene pad, and pressing a metal sheet onto the side of the graphene pad with the first adhesive. The graphene pad has a horizontal direction perpendicular to the thickness direction, and the graphene pad includes a plurality of graphene sheets arranged in sequence along the horizontal direction, with a gap between any two adjacent graphene sheets. The thickness of the metal sheet is 1μm to 1000μm.

2. The method for preparing the composite thermally conductive pad according to claim 1, characterized in that, The thickness of the metal sheet is 5μm to 50μm.

3. The method for preparing the composite thermally conductive pad according to claim 1, characterized in that, The metal sheet includes aluminum sheet, copper sheet, nickel sheet, or indium sheet.

4. The method for preparing the composite thermally conductive pad according to claim 3, characterized in that, The metal sheet is an aluminum sheet.

5. The method for preparing the composite thermally conductive pad according to claim 1, characterized in that, The viscosity of the first adhesive is ≤100 mPa*S.

6. The method for preparing the composite thermally conductive pad according to claim 5, characterized in that, The first adhesive is an organosilicone adhesive.

7. The method for preparing the composite thermally conductive pad according to claim 1, characterized in that, The method for removing the first adhesive from the surface of the graphene pad includes wiping it off with blotting paper.

8. The method for preparing the composite thermally conductive pad according to claim 1, characterized in that, The method of pressing the metal sheet and the graphene pad together includes: The metal sheet and the graphene gasket are pressed together using a pressing device. The pressing temperature is 50℃~150℃, the pressing pressure is 1MPa~100MPa, and the pressing time is 5min~20min.

9. The method for preparing the composite thermally conductive pad according to claim 1, characterized in that, The thickness of the graphene gasket is 0.1mm to 5mm.

10. The method for preparing the composite thermally conductive pad according to claim 9, characterized in that, The thickness of the graphene gasket is 0.1mm to 1mm.

11. The method for preparing the composite thermally conductive pad according to claim 1, characterized in that, Adjacent graphene sheets are bonded together with a second adhesive, which is distributed in an island-like pattern.

12. A composite thermally conductive pad, characterized in that, The composite thermal pad is prepared by the method of any one of claims 1 to 11.

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