Preparation method of copper-based diamond composite material

Abstract

The invention discloses a preparation method of a copper-based diamond composite material, which comprises the following steps: providing a copper base material, the copper base material comprises a first surface and a second surface which are opposite to each other, the thickness of the copper base material is 0.1-5mm, the areas of the first surface and the second surface are 100mm < 2 >-2000mm < 2 >, and the ratio of the area to the thickness of the copper base material is (100: 1)-(5000: 1); a stress buffer layer is prepared on the first surface of the copper base material, the first preparation temperature during preparation is controlled to be 150-900 DEG C, the thickness of the stress buffer layer is controlled to be 1-80 microns, and the thermal expansion coefficient of the stress buffer layer is smaller than that of the copper base material; and a diamond film layer is prepared on the second surface of the copper base material, the second preparation temperature during preparation is controlled to be 600-900 DEG C, and the thickness of the diamond film layer is controlled to be 1-30 microns. According to the method, interface cracking, debonding and buckling deformation of the copper-based diamond composite material can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite material preparation, and particularly relates to a preparation method of copper-based diamond composite material. BACKGROUND

[0002] The development of the microelectronic field promotes the continuous increase of the integration and power density of integrated circuits, resulting in the sharp rise of the heat generated by the chip when running. This problem puts higher requirements on the heat dissipation system of electronic equipment, because the excessively high working temperature can significantly reduce the reliability and shorten the service life of the equipment. The copper-based diamond composite material has become one of the main directions of the research and development of the new generation of thermal management materials due to its excellent thermal conductivity.

[0003] With the development of chemical vapor deposition process, some researchers try to directly deposit diamond film on the copper substrate to prepare diamond film / copper composite material. However, due to the poor wettability of diamond and copper and the significant difference between the thermal expansion coefficients of the two, the thermal expansion coefficient of copper is 17x10 -6 / K, and the thermal expansion coefficient of diamond is 1x10 -6 / K, which causes significant interfacial thermal stress between the two during the deposition process, and further causes the warping of the copper substrate / diamond composite matrix, the interfacial cracking and debonding, etc., which limits the application of the material. SUMMARY

[0004] The present application aims at the deficiencies of the prior art, and provides a preparation method of copper-based diamond composite material, which aims to solve the above technical problems and achieve the purpose of preventing the copper-based diamond composite material from warping and cracking.

[0005] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0006] The present application provides a preparation method of copper-based diamond composite material, which comprises the following steps: providing a copper substrate, the copper substrate comprising opposite first and second surfaces, the thickness of the copper substrate being 0.1mm-5mm, the area of the first and second surfaces being 100mm 2 ~2000mm 2 , the ratio of the area of the copper substrate to the thickness of the copper substrate being 100:1-5000:1; preparing a stress buffer layer on the first surface of the copper substrate, the first preparation temperature being controlled at 150℃-900℃ during preparation, the thickness of the stress buffer layer being controlled at 1μm-80μm during preparation, and the thermal expansion coefficient of the stress buffer layer being less than the thermal expansion coefficient of the copper substrate; and preparing a diamond film layer on the second surface of the copper substrate, the second preparation temperature being controlled at 600℃-900℃ during preparation, and the thickness of the diamond film layer being controlled at 1μm-30μm during preparation.

[0007] The technical scheme of the preparation method of the copper-based diamond composite material in the first aspect of the present application controls the thickness of the stress buffer layer and the first preparation temperature to prepare the stress buffer layer on the first surface of the copper base material, controls the thickness of the diamond film layer and the second preparation temperature to prepare the diamond film layer on the second surface of the copper base material, and finally makes the thermal stress on both sides of the copper-based diamond composite material offset in two directions, so that the copper-based diamond composite material is not easy to warp and the interface is not easy to crack.

[0008] The second aspect of the present application provides a preparation method of a copper-based diamond composite material, comprising the following steps: providing a copper base material, the copper base material comprising opposite first and second surfaces; selecting the type of stress buffer layer on the first surface of the copper base material and the corresponding preparation process parameters, wherein the preparation process parameters include the thickness of the stress buffer layer and the first preparation temperature; calculating the first stress generated between the stress buffer layer and the copper base material when the stress buffer layer is reduced from the first preparation temperature to room temperature; preparing the stress buffer layer on the first surface of the copper base material according to the type of the stress buffer layer and the corresponding preparation process parameters; selecting the type of diamond film layer on the second surface of the copper base material and the corresponding preparation process parameters, wherein the preparation process parameters include the thickness of the diamond film layer and the second preparation temperature; calculating the second stress generated between the diamond film layer and the copper base material when the diamond film layer is reduced from the second preparation temperature to room temperature, the second stress being opposite in direction to the first stress, and the difference between the second stress and the first stress being less than or equal to 1.5 GPa; and preparing the diamond film layer on the second surface of the copper base material according to the type of the diamond film layer and the corresponding preparation process parameters.

[0009] The technical scheme of the preparation method of the copper-based diamond composite material in the second aspect of the present application selects the type of the stress buffer layer and the diamond film and the preparation process parameters, calculates the first stress generated between the stress buffer layer and the copper base material when the stress buffer layer is cooled and the second stress generated between the diamond film layer and the copper base material when the diamond film layer is cooled, and makes the first stress between the stress buffer layer and the copper base material on the first surface of the copper base material and the second stress between the diamond film layer and the copper base material on the second surface of the copper base material offset in two directions, so as to reduce the stress difference generated between the base layer structures, and realize low warping degree and interface not easy to debond or crack of the copper-based diamond composite material. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0011] Figure 1 A flow chart of a preparation method of a copper-based diamond composite material according to some embodiments of the present application;

[0012] Figure 2 A flow chart of a preparation method of a copper-based diamond composite material according to some embodiments of the present application;

[0013] Figure 3 A flow chart of a preparation method of a copper-based diamond composite material according to some embodiments of the present application;

[0014] Figure 4 A flow chart of a preparation method of a copper-based diamond composite material according to some embodiments of the present application;

[0015] Figure 5 A flow chart of a preparation method of a copper-based diamond composite material according to some embodiments of the present application;

[0016] Figure 6 A macroscopic morphology schematic diagram of a copper-based diamond composite material disclosed by Comparative Example 1;

[0017] Figure 7 A macroscopic morphology schematic diagram of a copper-based diamond composite material disclosed by Comparative Example 2;

[0018] Figure 8 A macroscopic morphology schematic diagram of a copper-based diamond composite material disclosed by Example 3 of the present application;

[0019] Figure 9 A warping radius measurement diagram of a copper-based diamond composite material disclosed by Comparative Example 1;

[0020] Figure 10 A warping radius measurement diagram of a copper-based diamond composite material disclosed by Comparative Example 2;

[0021] Figure 11 A warping radius measurement diagram of a copper-based diamond composite material disclosed by Example 3 of the present application;

[0022] Figure 12 A warping radius measurement diagram of a copper-based diamond composite material disclosed by Example 5 of the present application;

[0023] Figure 13 A Raman spectrum test diagram of a copper-based diamond composite material disclosed by Comparative Example 1 and a copper-based diamond composite material disclosed by Example 3 of the present application;

[0024] Figure 14 A test actual object diagram of a copper-based diamond composite material disclosed by Example 3 of the present application, alumina and aluminum nitride;

[0025] Figure 14 b is a heat dissipation temperature measurement diagram of the copper-based diamond composite material disclosed in Embodiment 3 of the present application and aluminum oxide and aluminum nitride at different powers;

[0026] Figure 14 c is a curve diagram of the heat dissipation temperature of the copper-based diamond composite material disclosed in Embodiment 3 of the present application and aluminum oxide and aluminum nitride with the change of power;

[0027] Figure 15 is a micro-morphology schematic diagram of the nano-diamond film layer of the first surface of the copper-based diamond composite material disclosed in Embodiment 3 of the present application;

[0028] Figure 16 is a micro-morphology schematic diagram of the micro-diamond film layer of the second surface of the copper-based diamond composite material disclosed in Embodiment 3 of the present application;

[0029] Figure 17 is a structure schematic diagram of the copper-based diamond composite material disclosed in some embodiments of the present application;

[0030] Figure 18 is a structure schematic diagram of the copper-based diamond composite material disclosed in some other embodiments of the present application;

[0031] Figure 19 is a structure schematic diagram of the copper-based diamond composite material disclosed in some other embodiments of the present application.

[0032] Explanation of reference signs:

[0033] 100, copper-based diamond composite material;

[0034] 1, copper base material; 2, second transition layer; 3, first transition layer; 4, diamond film layer; 5, stress buffer layer. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0036] It should be understood that when used in the specification and the appended claims, the terms "comprise" and "include" indicate the presence of described features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or sets thereof.

[0037] It should also be understood that the terms used in the specification and the claims are for the purpose of describing particular embodiments thereof and are not intended to be limiting thereof. As used in this specification and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0038] It should further be understood that the term "and / or" as used in the specification and the claims is used to mean any one of the items in the list, or any combination of items in the list, and includes all possible combinations of the items.

[0039] Some embodiments of the present application will now be described in detail in connection with the accompanying drawings. The following embodiments and features are not mutually exclusive and can be combined with each other.

[0040] The following examples and comparative examples are not intended to be limiting of the present application. Unless otherwise indicated, conventional or manufacturer's recommended conditions were used. Unless otherwise indicated, the reagents or materials were obtained as generally available reagents from commercial suppliers and used without further purification.

[0041] In the preparation of copper-based diamond composite material, the thermal expansion coefficient of copper is 17x10 -6 / K, the thermal expansion coefficient of diamond is 1x10 -6 / K, and the difference between the two is significant. During high-temperature deposition (>750℃), the thermal stress as high as 10GPa will be generated from the deposition temperature to room temperature. In the traditional process of depositing diamond film on one side of copper substrate, the thermal stress will cause significant change in the curvature radius of the substrate, leading to interface cracking and warping deformation. Figure 6 and Figure 7

[0042] In view of this, the present application aims to provide a preparation method of copper-based diamond composite material 100, which can prepare copper-based diamond composite material 100 with low warping, interface not easy to debond, and surface not easy to crack.

[0043] Please refer to Figure 1 , Figure 1 is a flowchart of the preparation method of copper-based diamond composite material 100 provided by the present application. The preparation method of copper-based diamond composite material 100 adopts an asymmetric double-sided structure design, which can make the prepared copper-based diamond composite material 100 have low warping, interface not easy to debond, and surface not easy to crack, and has broad application prospects in the field of high-power electronics.

[0044] As shown in Figure 1 , the preparation method of copper-based diamond composite material 100 provided by the present application includes steps S110 to S130. ​

[0045] S110, Provide copper substrate 1, such as Figure 17 , Figure 18 and Figure 19 As shown, the copper substrate 1 includes a first surface and a second surface opposite to each other. The thickness of the copper substrate 1 is 0.1 mm to 5 mm, and the area of ​​the first surface and the second surface is 100 mm². 2 ~2000mm 2 The ratio of the area of ​​copper substrate 1 to the thickness of copper substrate 1 is 100:1 to 5000:1.

[0046] In some embodiments of this application, if the copper substrate 1 is too thick (>5mm), the volume fraction of diamond will be reduced, resulting in obstructed heat conduction paths and a decrease in the overall thermal conductivity of the copper-diamond composite material 100; if it is too thin (<0.1mm), it will be difficult to form an effective support structure and is prone to cracking during deposition or sintering. Therefore, the thickness of the copper substrate 1 in this application ranges from 0.1mm to 5mm, for example, the thickness of the copper substrate 1 can be 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.8mm, 1mm, 2mm, 3mm, 4mm, and 5mm, etc. In some more specific embodiments, the thickness of the copper substrate 1 is limited to the range of 0.3 mm to 1 mm. For example, the thickness of the copper substrate 1 can be 0.3 mm, 0.4 mm, 0.5 mm, 0.8 mm and 1 mm, etc. This allows the copper substrate 1 of this application to provide sufficient support for the adhesion of other material layers, and also has sufficient mechanical structural strength. It is not easy to crack or deform under stress, and it can also save manufacturing costs. It provides the necessary thermal conductivity basis for the heat dissipation of each layer of material, so that the copper-based diamond composite material 100 with the above thickness range has high overall thermal conductivity, controllable manufacturing cost and certain structural strength.

[0047] When the area of ​​copper substrate 1 is too large (>2000mm²) 2 When the area is too small (<100mm), the interface is prone to peeling due to thermal stress during the cooling process, thus affecting product performance; while if the area is too small (<100mm), the interface is prone to peeling due to thermal stress during the cooling process, thus affecting product performance. 2 During deposition, even small fluctuations in process parameters can easily lead to instability in the deposition process, which is detrimental to production control. Therefore, in this application, the areas of the first and second surfaces of the copper substrate 1 are approximately equal, and their values ​​range from 100 mm². 2 ~2000mm 2 For example, the area of ​​the first and second surfaces of the copper substrate 1 can be 100 mm². 2 400mm 2 500mm 2 600mm 2 706mm 2 800mm 2 900mm 2 1050mm2 1256 mm 2 and 2000 mm 2 In some more specific embodiments, the area of the first surface and the second surface of the copper substrate 1 is limited to 300 mm 2 ~ 800 mm 2 For example, the area of the first surface and the second surface of the copper substrate 1 can be 300 mm 2 , 500 mm 2 , 600 mm 2 , 706 mm 2 and 800 mm 2 In some more specific embodiments, the area of the first surface and the second surface of the copper substrate 1 is limited to 300 mm

[0048] When the area to thickness ratio of the copper substrate 1 is too large (> 5000:1), the copper substrate 1 will be insufficiently rigid during the preparation of the diamond film layer 4, resulting in warping and cracking. When the area to thickness ratio of the copper substrate 1 is too small (< 100:1), the thermal stress will concentrate and cause interfacial peeling. Therefore, the area to thickness ratio of the copper substrate 1 according to the present application is limited to 100:1~5000:1, for example, the area to thickness ratio of the copper substrate 1 can be 100:1, 200:1, 706:1, 750:1, 1000:1, 1125:1, 1257:1, 3500:1, 4186:1 and 5000:1. In some more specific embodiments, the area to thickness ratio of the copper substrate 1 is limited to 800:1~2000:1, for example, the area to thickness ratio of the copper substrate 1 can be 800:1, 1000:1, 1125:1, 1257:1 and 2000:1, so that the transverse to longitudinal thermal gradient ratio of the copper substrate 1 according to the present application is close to 1:1, and the thermal stress is more evenly distributed.

[0049] S120, preparing the stress buffer layer 5 on the first surface of the copper substrate 1, the first preparation temperature during preparation is controlled to be 150°C~900°C, the thickness of the stress buffer layer 5 during preparation is controlled to be 1 μm~80 μm, and the thermal expansion coefficient of the stress buffer layer 5 is less than the thermal expansion coefficient of the copper substrate 1.

[0050] In some embodiments of the present application, the thermal expansion coefficient of the stress buffer layer 5 is less than the thermal expansion coefficient of the copper substrate 1, and when the temperature changes, the shrinkage of the stress buffer layer 5 is much smaller than that of the copper substrate 1, thereby forming a reverse first stress on the surface of the copper substrate 1.

[0051] In some embodiments, the stress buffer layer 5 can be at least one of a nanocrystalline diamond film, a diamond-like carbon film, and a cemented carbide film.

[0052] The coefficient of thermal expansion of the nanocrystalline diamond film is significantly lower than that of the copper substrate 1, where the coefficient of thermal expansion of the nanocrystalline diamond film is 1x10 -6 / K, and the coefficient of thermal expansion of the copper substrate 1 is 17x10 -6 / K, and the difference in the coefficients of thermal expansion of the two is used to form a first stress in the opposite direction on the surface of the copper substrate 1, and at the same time, the film layer has ultrahigh hardness and high thermal conductivity, which can effectively disperse the local stress concentration of the copper substrate 1 and accelerate heat conduction, and reduce fatigue damage caused by thermal cycling.

[0053] The coefficient of thermal expansion of the diamond-like carbon film is lower than that of the copper substrate 1, where the coefficient of thermal expansion of the diamond-like carbon film is 2.8x10 -6 / K, and the coefficient of thermal expansion of the copper substrate 1 is 17x10 -6 / K, and the difference in the coefficients of thermal expansion of the two is used to form a first stress in the opposite direction on the surface of the copper substrate 1, and in addition, the controllability of the proportion of tetrahedral diamond bonds (sp3) and triangular graphite bonds (sp2) in the film layer can optimize the thermal expansion mismatch gradient, forming a controllable residual compressive stress distribution to avoid interface peeling.

[0054] The coefficient of thermal expansion of the cemented carbide film is lower than that of the copper substrate 1, where the coefficient of thermal expansion of the cemented carbide film is 6x10 -6 / K, and the coefficient of thermal expansion of the copper substrate 1 is 17x10 -6 / K, and the difference in the coefficients of thermal expansion of the two is used to form a first stress in the opposite direction on the surface of the copper substrate 1, and at the same time, its ultrahigh hardness can resist plastic deformation of the copper substrate 1 under mechanical stress.

[0055] When the first preparation temperature is higher than 900℃, the stress buffer layer 5 is prone to excessive crystallization, resulting in a significant decrease in the interface bonding strength with the copper substrate 1; and when the first preparation temperature is lower than 150℃, the stress buffer layer 5 cannot be fully densified, resulting in an increase in porosity and interface thermal stress, which in turn weakens the thermal stress offset effect. Therefore, the first preparation temperature is controlled to be 150℃-900℃ in the present application, for example, the first preparation temperature can be 150℃, 200℃, 260℃, 300℃, 400℃, 450℃, 500℃, 550℃, 660℃, 680℃, 700℃, 750℃, 800℃ and 900℃, etc., so that the stress buffer layer 5 prepared in the present application has a moderate crystallization degree and a high interface bonding degree with the copper substrate 1.

[0056] When the thickness of the stress buffer layer 5 is greater than 80 μm, the process control of the preparation of the stress buffer layer 5 is difficult, and the film layer of the stress buffer layer 5 is not uniform. When the thickness of the stress buffer layer 5 is less than 1 μm, the stress buffer layer 5 cannot disperse the interface thermal stress, and cracks are prone to occur. Therefore, the thickness of the stress buffer layer 5 is controlled to be 1 μm to 80 μm during preparation, for example, the thickness of the stress buffer layer 5 can be 1 μm, 5 μm, 10 μm, 12 μm, 13 μm, 20 μm, 22 μm, 30 μm, 55 μm, 60 μm and 80 μm, so that the film layer of the stress buffer layer 5 prepared by the application is more uniform, and cracks are not prone to occur.

[0057] In some embodiments, the stress buffer layer 5 is a nanocrystalline diamond film having a thickness of 1 μm to 30 μm, such as 1 μm, 3 μm, 5 μm, 5.5 μm, 6 μm, 10 μm, 18 μm, 20 μm, 25 μm, and 30 μm, and the like. The nanocrystalline diamond film is deposited on the first surface of the copper substrate 1 using a hot filament chemical vapor deposition process having the following process parameters: a pressure in the deposition furnace of 500 Pa to 2000 Pa, such as 500 Pa, 800 Pa, 900 Pa, 1000 Pa, 1300 Pa, and 2000 Pa, and the like; a power of the single hot filament of 1.2 kW to 1.8 kW, such as 1.2 kW, 1.4 kW, 1.5 kW, 1.6 kW, 1.7 kW, and 1.8 kW, and the like; a first deposition temperature of 600 °C to 750 °C, such as 600 °C, 630 °C, 650 °C, 680 °C, 700 °C, 720 °C, and 750 °C, and the like; a distance between the hot filament and the substrate of 10 mm to 16 mm, such as 10 mm, 10.5 mm, 11 mm, 12 mm, 12.5 mm, 15 mm, and 16 mm, and the like; a flow rate of H2of 300 seem to 600 seem, such as 300 seem, 360 seem, 400 seem, 460 seem, 500 seem, 550 seem, and 600 seem, and the like; a flow rate of CH4of 15 seem to 30 seem, such as 15 seem, 18 seem, 20 seem, 25 seem, and 30 seem, and the like; a flow rate ratio of CH4to H2of 3.0% to 6.0%, such as 3.0%, 4.0%, 4.2%, 4.3%, 4.5%, 5.0%, and 6.0%, and the like; a first deposition time of 1 h to 20 h, such as 1 h, 5 h, 6 h, 10 h, 18 h, and 20 h, and the like; and a cooling rate of 5 °C / h to 30 °C / h, such as 5 °C / h, 15 °C / h, 20 °C / h, 27 °C / h, and 30 °C / h, and the like. In some more specific embodiments, the process parameters are limited to a pressure in the deposition furnace of 900 Pa to 1200 Pa, a power of the single hot filament of 1.4 kW to 1.6 kW, a first deposition temperature of 680 °C to 720 °C, a distance between the hot filament and the substrate of 12 mm to 14 mm, a flow rate of H2of 450 seem to 550 seem, a flow rate of CH4of 20 seem to 25 seem, and a flow rate ratio of CH4to H2of 4.0% to 5.0%.

[0058] In yet some embodiments, the stress buffer layer 5 is a nanocrystalline diamond film, and the thickness of the nanocrystalline diamond film is 1 μm to 30 μm. On the premise that the technical solutions are not contradictory, the nanocrystalline diamond film can be prepared on the first surface of the copper substrate 1 by using a microwave plasma chemical vapor deposition method, and the preparation process parameters are as follows: the microwave power is 2 kW to 6 kW, for example, the microwave power can be 2 kW, 3 kW, 4 kW, 6 kW, etc.; the cavity gas pressure is 2000 Pa to 5000 Pa, for example, the cavity gas pressure can be 2000 Pa, 2300 Pa, 2600 Pa, 2800 Pa, 3000 Pa, 5000 Pa, etc.; the first preparation temperature is 600 ℃ to 750 ℃, for example, the first preparation temperature can be 600 ℃, 620 ℃, 660 ℃, 710 ℃, 750 ℃, etc.; the H2 flow rate is 100 sccm to 500 sccm, for example, the H2 flow rate can be 100 sccm, 130 sccm, 150 sccm, 200 sccm, 400 sccm, 500 sccm, etc.; the CH4 flow rate is 5 sccm to 35 sccm, for example, the CH4 flow rate can be 5 sccm, 6 sccm, 7 sccm, 10 sccm, 15 sccm, 26 sccm, 35 sccm, etc.; the CH4 to H2 flow rate ratio is 3.0% to 7.0%, for example, the CH4 to H2 flow rate ratio can be 3.0%, 4.0%, 4.3%, 5.5%, 7.0%, etc.; the first preparation time is 3 h to 12 h, for example, the first preparation time can be 3 h, 4 h, 5 h, 7 h, 10 h, 12 h, etc.; and the cooling rate is 30 ℃ / h to 60 ℃ / h, for example, the cooling rate can be 30 ℃ / h, 35 ℃ / h, 40 ℃ / h, 50 ℃ / h, 60 ℃ / h, etc.

[0059] By controlling the thickness and the first preparation temperature of the nanocrystalline diamond film prepared by using the hot filament chemical vapor deposition method and the microwave plasma chemical vapor deposition method, the nanocrystalline diamond film is prepared on the first surface of the copper substrate 1, so that the film layer of the nanocrystalline diamond film is more uniform, and the second stress generated during preparation of the diamond film layer 4 can be offset.

[0060] In some embodiments, the stress buffer layer is a diamond-like carbon film, the thickness of the diamond-like carbon film is 5 μm to 60 μm, for example, the thickness can be 5 μm, 6 μm, 11 μm, 12 μm, 13 μm, 19 μm, 35 μm, 55 μm and 60 μm, etc., the diamond-like carbon film is prepared on the first surface of the copper substrate by a filtered cathodic arc method, and the corresponding preparation process parameters are as follows: the cavity pressure is adjusted to 1 Pa to 10 Pa, for example, the cavity pressure can be 1 Pa, 3 Pa, 5 Pa, 8 Pa, 9 Pa and 10 Pa, etc., the arc current is 50 A to 200 A, for example, the arc current can be 50 A, 60 A, 70 A, 90 A, 100 A, 120 A, 180 A and 200 A, etc., the substrate bias is -50 V to -500 V, for example, the substrate bias can be -50 V, -80 V, -100 V, -270 V, -360 V, -400 V and -500 V, etc., the first preparation temperature is 150 °C to 400 °C, for example, the first preparation temperature can be 150 °C, 190 °C, 230 °C, 260 °C, 300 °C, 340 °C and 400 °C, etc., the distance between the arc target material and the substrate is 80 mm to 150 mm, for example, the distance between the arc target material and the substrate can be 80 mm, 85 mm, 90 mm, 100 mm, 110 mm, 130 mm and 150 mm, etc., the Ar flow rate is 200 sccm to 800 sccm, for example, the Ar flow rate can be 200 sccm, 300 sccm, 360 sccm, 450 sccm, 600 sccm, 720 sccm and 800 sccm, etc., the H2 flow rate is 50 sccm to 300 sccm, for example, the H2 flow rate can be 50 sccm, 60 sccm, 80 sccm, 100 sccm, 170 sccm, 240 sccm and 300 sccm, etc., the H2 / Ar flow rate ratio is 5.0% to 15.0%, for example, the H2 / Ar flow rate ratio can be 5.0%, 6.5%, 8.0%, 10.0%, 11.5% and 15.0%, etc., the first preparation time is 5 h to 30 h, for example, the first preparation time can be 5 h, 6 h, 8 h, 12 h, 19 h, 25 h and 30 h, etc., the cooling rate is 5 °C / h to 30 °C / h, for example, the cooling rate can be 5 °C / h, 12 °C / h, 18 °C / h, 20 °C / h, 26 °C / h and 30 °C / h, etc. In some more specific embodiments, the preparation process parameters are limited as follows: the cavity pressure is adjusted to 2 Pa to 5 Pa, the arc current is 80 A to 150 A, the substrate bias is -100 V to -300 V, the first preparation temperature is 200 °C to 300 °C, the distance between the arc target material and the substrate is 100 mm to 120 mm, the Ar flow rate is 600 sccm to 800 sccm, the H2 flow rate is 60 sccm to 200 sccm, and the H2 / Ar flow rate ratio is 8.0% to 12.0%.

[0061] By controlling the thickness and the first preparation temperature of the diamond-like film prepared by the filter cathode arc method, the diamond-like film is prepared on the first surface of the copper substrate 1, so that the film layer of the diamond-like film is more uniform, and the second stress generated in the preparation of the diamond film layer 4 can be offset.

[0062] In some embodiments, the stress buffer layer 5 is a hard alloy film, the hard alloy film is at least one of titanium carbide, tungsten carbide, tantalum carbide, titanium carbonitride and tungsten boride, the thickness of the hard alloy film is 5 μm to 80 μm, for example, the thickness can be 5 μm, 13 μm, 20 μm, 28 μm, 30 μm, 35 μm, 55 μm, 70 μm and 80 μm, etc. The hard alloy film is prepared on the first surface of the copper substrate 1 by a magnetron sputtering method, and the corresponding preparation process parameters are as follows: the target material is the material of the prepared hard alloy film, the Ar flow rate is set to 50 sccm to 200 sccm, for example, the Ar flow rate can be 50 sccm, 55 sccm, 60 sccm, 90 sccm, 95 sccm, 130 sccm, 160 sccm and 200 sccm, etc., the CH4 flow rate is 3 sccm to 10 sccm, for example, the CH4 flow rate can be 3 sccm, 4 sccm, 5 sccm, 7 sccm, 9 sccm and 10 sccm, etc., the cavity pressure is 0.5 Pa to 2.0 Pa, for example, the pressure can be 0.5 Pa, 0.6 Pa, 1.0 Pa, 1.5 Pa and 2.0 Pa, etc., the power is 80 W to 200 W, for example, the power can be 80 W, 85 W, 100 W, 110 W, 150 W and 200 W, etc., the cavity temperature is 20°C to 100°C, for example, the cavity temperature can be 20°C, 25°C, 36°C, 45°C, 60°C, 90°C and 100°C, etc., the first preparation temperature is 150°C to 500°C, for example, the first preparation temperature can be 150°C, 230°C, 300°C, 360°C, 450°C and 500°C, etc., the first preparation time is 1 h to 20 h, for example, the deposition time can be 1 h, 3 h, 7 h, 9 h, 12 h, 15 h and 20 h, etc., the cooling rate is 10°C / h to 30°C / h, for example, the cooling rate can be 10°C / h, 15°C / h, 18°C / h, 20°C / h, 25°C / h and 30°C / h, etc.

[0063] By controlling the thickness and the first preparation temperature of the diamond-like film prepared by the filter cathode arc method, the diamond-like film is prepared on the first surface of the copper substrate 1, so that the film layer of the diamond-like film is more uniform, and the second stress generated in the preparation of the diamond film layer 4 can be offset.

[0064] In some embodiments, when the first stress of the stress buffer layer 5 exceeds 10 GPa, it will cause the stress buffer layer 5 to crack and fall off, thereby affecting the quality of the subsequent preparation of the diamond film layer 4. Therefore, the first stress of the stress buffer layer 5 is controlled to be less than or equal to 10 GPa in the present application, so as to avoid film layer cracking and improve the density, and further improve the stability of the subsequent diamond film layer 4.

[0065] The thermal stress (i.e., the first stress) of the first surface stress buffer layer 5 is calculated according to the following formula:

[0066]

[0067] In the formula, E1 is the elastic modulus of the stress buffer layer 5, v1 is the Poisson's ratio of the stress buffer layer 5, a1 is the thermal expansion coefficient of the stress buffer layer 5, AT1 is the temperature difference between the first preparation temperature and the room temperature, a2 is the thermal expansion coefficient of the copper substrate 1, and T1 is the first preparation temperature. Cu The thermal expansion coefficient of the copper substrate 1.

[0068] In S130, the diamond film layer 4 is prepared on the second surface of the copper substrate 1, and the second preparation temperature during the preparation is controlled to be 600-900°C. The thickness of the diamond film layer 4 is controlled to be 1-30 μm during the preparation.

[0069] In some embodiments, the diamond film layer 4 can be a nanocrystalline diamond film or a microcrystalline diamond film. The high hardness and low stress characteristics of the nanocrystalline diamond film complement the difference in the elastic modulus of the stress buffer layer 5, offset the first stress, and at the same time, its high thermal conductivity can directly reduce the chip junction temperature and reduce the fatigue damage caused by thermal cycling. The uniform grain structure of the microcrystalline diamond film cooperates with the residual compressive stress of the stress buffer layer 5 to offset the first stress, and at the same time, the medium thermal conductivity combined with its toughness can maintain the stability of the heat dissipation channel under dynamic working conditions.

[0070] When the second preparation temperature is higher than 900°C, the diamond film layer 4 is prone to over-crystallization, which leads to a significant decrease in the interfacial bonding strength with the copper substrate 1. When the second preparation temperature is lower than 600°C, the diamond film layer 4 cannot fully nucleate and grow, which leads to a decrease in the density of the film layer. Therefore, the second preparation temperature is controlled to be 600-900°C in the present application, for example, the second preparation temperature can be 600°C, 680°C, 700°C, 750°C, 800°C, 820°C, 850°C and 900°C, etc., so that the diamond film layer 4 prepared in the present application has strong stability and moderate crystallinity.

[0071] When the thickness of the diamond film layer 4 is greater than 30 μm, the non-uniformity of the prepared diamond film layer 4 increases, resulting in local thermal stress concentration; and when the thickness of the diamond film layer 4 is less than 1 μm, the film layer cannot form a complete continuous crystal structure. Therefore, the thickness of the diamond film layer 4 prepared in the present application is controlled to be 1 μm to 30 μm, for example, the thickness of the diamond film layer 4 can be 1 μm, 3 μm, 4.8 μm, 5 μm, 5.5 μm, 6 μm, 8 μm, 10 μm, 16 μm, 20 μm, 25 μm, 28 μm and 30 μm, etc., so that the film layer thickness of the diamond film layer 4 prepared in the present application is uniform, and the risk of crack generation is reduced.

[0072] In some embodiments, the diamond film layer 4 is a nanocrystalline diamond film having a thickness of 1 μm to 30 μm, such as 1 μm, 3 μm, 5 μm, 5.5 μm, 6 μm, 10 μm, 18 μm, 20 μm, 25 μm, and 30 μm, and is prepared on the second surface of the copper substrate 1 by hot filament chemical vapor deposition, with the corresponding process parameters being: a pressure in the deposition furnace of 500 Pa to 2000 Pa, such as 500 Pa, 800 Pa, 900 Pa, 1000 Pa, 1300 Pa, and 2000 Pa; a power of a single hot filament of 1.2 kW to 1.8 kW, such as 1.2 kW, 1.4 kW, 1.5 kW, 1.6 kW, 1.7 kW, and 1.8 kW; a second preparation temperature of 600 °C to 750 °C, such as 600 °C, 630 °C, 650 °C, 680 °C, 700 °C, 720 °C, and 750 °C; a distance between the hot filament and the substrate of 10 mm to 16 mm, such as 10 mm, 10.5 mm, 11 mm, 12 mm, 12.5 mm, 15 mm, and 16 mm; a flow rate of H2of 300 seem to 600 seem, such as 300 seem, 360 seem, 400 seem, 460 seem, 500 seem, 550 seem, and 600 seem; a flow rate of CH4of 15 seem to 30 seem, such as 15 seem, 18 seem, 20 seem, 25 seem, and 30 seem; a flow rate ratio of CH4to H2of 3.0% to 6.0%, such as 3.0%, 4.0%, 4.2%, 4.3%, 4.5%, 5.0%, and 6.0%; a second preparation time of 1 h to 20 h, such as 1 h, 5 h, 6 h, 10 h, 18 h, and 20 h; and a cooling rate of 5 °C / h to 30 °C / h, such as 5 °C / h, 15 °C / h, 20 °C / h, 27 °C / h, and 30 °C / h. In some more specific embodiments, the process parameters are limited to: a pressure in the deposition furnace of 900 Pa to 1200 Pa; a power of a single hot filament of 1.4 kW to 1.6 kW; a second preparation temperature of 680 °C to 720 °C; a distance between the hot filament and the substrate of 12 mm to 14 mm; a flow rate of H2of 450 seem to 550 seem; a flow rate of CH4of 20 seem to 25 seem; and a flow rate ratio of CH4to H2of 4.0% to 5.0%.

[0073] In yet some embodiments, the diamond film layer is a nanocrystalline diamond film, and the thickness of the nanocrystalline diamond film is 1 μm to 30 μm. On the premise that the technical solutions are not contradictory, the aforementioned can be referred to, and here is not repeated. The nanocrystalline diamond film is prepared on the second surface of the copper substrate by a microwave plasma chemical vapor deposition method. The corresponding preparation process parameters are as follows: the microwave power is 2 kW to 6 kW, for example, the microwave power can be 2 kW, 3 kW, 4 kW, and 6 kW, etc.; the cavity gas pressure is 2000 Pa to 5000 Pa, for example, the cavity gas pressure can be 2000 Pa, 2300 Pa, 2600 Pa, 2800 Pa, 3000 Pa, and 5000 Pa, etc.; the second preparation temperature is 600 ℃ to 750 ℃, for example, the second preparation temperature can be 600 ℃, 620 ℃, 660 ℃, 710 ℃, and 750 ℃, etc.; the H2 flow rate is 100 sccm to 500 sccm, for example, the H2 flow rate can be 100 sccm, 130 sccm, 150 sccm, 200 sccm, 400 sccm, and 500 sccm, etc.; the CH4 flow rate is 5 sccm to 35 sccm, for example, the CH4 flow rate can be 5 sccm, 6 sccm, 7 sccm, 10 sccm, 15 sccm, 26 sccm, and 35 sccm, etc.; the CH4 to H2 flow rate ratio is 3.0% to 7.0%, for example, the CH4 to H2 flow rate ratio can be 3.0%, 4.2%, 5.5%, 6.8%, and 7.0%, etc.; the second preparation time is 3 h to 12 h, for example, the second preparation time can be 3 h, 4 h, 5 h, 7 h, 10 h, and 12 h, etc.; and the cooling rate is 30 ℃ / h to 60 ℃ / h, for example, the cooling rate can be 30 ℃ / h, 35 ℃ / h, 40 ℃ / h, 50 ℃ / h, and 60 ℃ / h, etc.

[0074] By controlling the thickness and the second preparation temperature of the nanocrystalline diamond film prepared by the aforementioned hot filament chemical vapor deposition method and the microwave plasma chemical vapor deposition method, the nanocrystalline diamond film is prepared on the second surface of the copper substrate 1, so that the film layer of the nanocrystalline diamond film is more uniform, and is not prone to warping and cracking.

[0075] In some embodiments, the diamond film layer is a microcrystalline diamond film having a thickness of 1 μm to 20 μm, such as 1 μm, 2 μm, 4.8 μm, 5 μm, 5.5 μm, 6 μm, 8 μm, 10 μm, 13 μm, 15 μm, and 20 μm, and is prepared on the second surface of the copper substrate by hot filament chemical vapor deposition, with corresponding process parameters of a pressure in the deposition furnace of 3000 Pa to 5000 Pa, such as 3000 Pa, 3100 Pa, 3800 Pa, 4000 Pa, 4500 Pa, and 5000 Pa, a power of a single hot filament of 1.5 kW to 2.5 kW, such as 1.5 kW, 1.6 kW, 1.7 kW, 1.9 kW, 2.0 kW, 2.1 kW, and 2.5 kW, a second preparation temperature of 780 °C to 900 °C, such as 780 °C, 790 °C, 800 °C, 820 °C, 850 °C, and 900 °C, a distance between the hot filament and the substrate of 8 mm to 12 mm, such as 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, and 12 mm, a flow rate of H2of 300 seem to 600 seem, such as 300 seem, 360 seem, 400 seem, 480 seem, 500 seem, 550 seem, and 600 seem, a flow rate of CH4of 5 seem to 15 seem, such as 5 seem, 7 seem, 10 seem, 11 seem, 12 seem, and 15 seem, a flow rate ratio of CH4to H2of 0.5% to 2.5%, such as 0.5%, 0.8%, 1.0%, 1.5%, 2.0%, 2.1%, 2.2%, and 2.5%, a second preparation time of 1 h to 18 h, such as 1 h, 3 h, 5 h, 7 h, 8 h, 10 h, 13 h, and 18 h, and a cooling rate of 5 °C / h to 15 °C / h, such as 5 °C / h, 8 °C / h, 10 °C / h, 12 °C / h, and 15 °C / h. In some more specific embodiments, the process parameters are limited to a pressure in the deposition furnace of 3800 Pa to 4500 Pa, a power of a single hot filament of 1.8 kW to 2.1 kW, a second preparation temperature of 820 °C to 850 °C, a distance between the hot filament and the substrate of 9.5 mm to 11 mm, a flow rate of H2of 450 seem to 550 seem, a flow rate of CH4of 8 seem to 12 seem, and a flow rate ratio of CH4to H2of 1.5% to 2.2%.

[0076] In yet some embodiments, the diamond film layer is a microcrystalline diamond film, the thickness of the microcrystalline diamond film is 1 μm to 20 μm, and on the premise that the technical solutions are not contradictory, the aforementioned can be referred to, and here is not repeated. The microcrystalline diamond film is prepared on the second surface of the copper substrate 1 by a microwave plasma chemical vapor deposition method, and the corresponding preparation process parameters are as follows: the microwave power is 4 kW to 6 kW, for example, the microwave power can be 4 kW, 4.5 kW, 5.5 kW, and 6 kW, etc.; the cavity gas pressure is 12000 Pa to 23000 Pa, for example, the cavity gas pressure can be 12000 Pa, 13000 Pa, 15000 Pa, 18000 Pa, 19000 Pa, 20000 Pa, and 23000 Pa, etc.; the second preparation temperature is 750 ℃ to 850 ℃, for example, the second preparation temperature can be 750 ℃, 760 ℃, 800 ℃, 820 ℃, and 850 ℃, etc.; the H2 flow rate is 100 sccm to 500 sccm, for example, the H2 flow rate can be 100 sccm, 180 sccm, 220 sccm, 350 sccm, 400 sccm, and 500 sccm, etc.; the CH4 flow rate is 2 sccm to 10 sccm, for example, the CH4 flow rate can be 2 sccm, 3 sccm, 6 sccm, 8 sccm, and 10 sccm, etc.; the CH4 to H2 flow rate ratio is 1.0% to 3.0%, for example, the CH4 to H2 flow rate ratio can be 1.0%, 1.5%, 2.0%, 2.3%, and 3.0%, etc.; the O2 flow rate and the N2 flow rate are optional parameters, wherein the O2 flow rate is 0.2 sccm to 2 sccm, for example, the O2 flow rate can be 0.2 sccm, 0.3 sccm, 0.6 sccm, 1.7 sccm, and 2 sccm, etc.; the N2 flow rate is 0.2 sccm to 1 sccm, for example, the N2 flow rate can be 0.2 sccm, 0.4 sccm, 0.5 sccm, 0.8 sccm, and 1 sccm, etc.; the second preparation time is 3 h to 12 h, for example, the second preparation time can be 3 h, 5 h, 6 h, 7 h, and 12 h, etc.; and the cooling rate is 20 ℃ / h to 50 ℃ / h, for example, the cooling rate can be 20 ℃ / h, 22 ℃ / h, 28 ℃ / h, 30 ℃ / h, 45 ℃ / h, and 50 ℃ / h, etc.

[0077] By controlling the thickness and the second preparation temperature of the microcrystalline diamond film prepared by the aforementioned hot filament chemical vapor deposition method and the microwave plasma chemical vapor deposition method, the microcrystalline diamond film prepared on the second surface of the copper substrate 1 is more uniform, and is not prone to warping and cracking.

[0078] In some embodiments, when the stress of the diamond film layer 4 exceeds 11 GPa, it will directly cause the film layer to break. Therefore, the second stress of the diamond film layer 4 is controlled to be less than or equal to 11 GPa in the present application, so as to reduce the film layer defects, enhance the interface bonding strength, and finally improve the process stability of the preparation of the diamond film layer 4.

[0079] wherein the thermal stress (i.e. the second stress) of the second surface diamond film layer 4 is calculated as follows:

[0080]

[0081] In the formula, E2 is the elastic modulus of the diamond film layer 4, v2 is the Poisson's ratio of the diamond film layer 4, and a2 is the thermal expansion coefficient of the diamond film layer 4; AT2 is the temperature difference between the second preparation temperature and the room temperature; a Cu is the thermal expansion coefficient of the copper substrate 1.

[0082] The stress offset is realized by the moment balance condition (Mnet≈0) as follows:

[0083]

[0084] In the formula, E1 is the elastic modulus of the stress buffer layer 5, v1 is the Poisson's ratio of the stress buffer layer 5, a1 is the thermal expansion coefficient of the stress buffer layer 5, H1 is the thickness of the stress buffer layer 5, and AT1 is the temperature difference between the first preparation temperature and the room temperature of the stress buffer layer 5; E2 is the elastic modulus of the diamond film layer 4, v2 is the Poisson's ratio of the diamond film layer 4, a2 is the thermal expansion coefficient of the diamond film layer 4, H2 is the thickness of the diamond film layer 4, and AT2 is the temperature difference between the second preparation temperature and the room temperature of the diamond film layer 4; a Cu is the thermal expansion coefficient of the copper substrate 1.

[0085] Then, the thickness, the second preparation temperature, the thermal expansion coefficient and other characteristics of the diamond film layer 4 can be calculated respectively by the above moment balance formula, so that the second stress generated between the diamond film layer 4 and the copper substrate 1 is opposite to the first stress generated between the selected stress buffer layer 5 and the copper substrate 1, the difference between the second stress and the first stress is less than or equal to 1.5 GPa, the resultant force after the first stress and the second stress offset has a small influence on the warping of the entire copper-based diamond composite material 100, the flatness of the entire copper-based diamond composite material 100 is high, the layer structure interface is not easy to debond, and the layer structure is not easy to crack.

[0086] From the above technical solutions can be seen, the preparation method of the copper-based diamond composite material 100 proposed by the application lays a foundation for the preparation of the stress buffer layer 5 and the diamond film layer 4 by controlling the thickness of the copper base material 1, the area of the first surface and the second surface, and the ratio of the area to the thickness; on this basis, the thickness of the stress buffer layer 5 and the first preparation temperature are further controlled, the stress buffer layer 5 is prepared on the first surface of the copper base material 1, and the thickness of the diamond film layer 4 and the second preparation temperature are simultaneously controlled, the diamond film layer 4 is prepared on the second surface of the copper base material 1; through the synergistic control of the above key parameters, the thermal stress on both sides of the copper-based diamond composite material 100 is finally offset in two directions, and the copper-based diamond composite material 100 is not easy to warp and the interface is not easy to crack.

[0087] The preparation method of another copper-based diamond composite material 100 proposed by the application will be described below.

[0088] As shown in Figure 2 , the preparation method of another copper-based diamond composite material 100 proposed by the application includes steps S100 to S700.

[0089] S100, providing a copper base material 1, as shown in Figure 17 , Figure 18 and Figure 19 , the copper base material 1 includes opposite first and second surfaces.

[0090] Among them, the thickness of the copper base material 1, the area of the first surface and the second surface, and the ratio of the area of the copper base material 1 to the thickness of the copper base material 1 can be referred to the foregoing description on the premise that the technical solutions are not contradictory, and will not be repeated here.

[0091] S200, selecting the type of the stress buffer layer 5 on the first surface of the copper base material 1 and the corresponding preparation process parameters, wherein the preparation process parameters include the thickness of the stress buffer layer 5 and the first preparation temperature.

[0092] The type of the stress buffer layer 5 and the corresponding preparation process parameters can be referred to the foregoing description on the premise that the technical solutions are not contradictory, and will not be repeated here.

[0093] S300, calculating the first stress generated by the stress buffer layer 5 from the first preparation temperature to room temperature and the copper base material 1.

[0094] Before the preparation of the stress buffer layer 5, the first stress generated between the stress buffer layer 5 and the copper substrate 1 when the stress buffer layer 5 is cooled from the first preparation temperature to room temperature can be simulated by computer simulation or theoretical calculation based on the preparation process parameters and the first stress calculation formula, and it is evaluated whether it is less than or equal to 10 GPa. If the simulation result meets the requirements, subsequent preparation process operations are performed. The first stress calculation formula can be referred to as described above, and a detailed description is omitted here.

[0095] S400, according to the type of stress buffer layer 5 and the corresponding preparation process parameters, the stress buffer layer 5 is prepared on the first surface of the copper substrate 1.

[0096] By using the selected type of stress buffer layer 5 and the corresponding preparation process parameters, the stress buffer layer 5 with the required thickness is prepared on the first surface of the copper substrate 1, and the first stress generated between the stress buffer layer 5 and the copper substrate 1 when the stress buffer layer 5 is cooled can be used to offset the second stress generated between the diamond film layer 4 and the copper substrate 1 when the diamond film layer 4 is cooled. In addition, the stress buffer layer 5 can provide wear resistance, corrosion resistance and electrical insulation as a protective layer.

[0097] S500, the type of diamond film layer 4 on the second surface of the copper substrate 1 and the corresponding preparation process parameters are selected, wherein the preparation process parameters include the thickness of the diamond film layer 4 and the second preparation temperature.

[0098] The type of diamond film layer 4 and the corresponding preparation process parameters can be referred to as described above, and a detailed description is omitted here.

[0099] S600, the second stress generated between the diamond film layer 4 and the copper substrate 1 when the diamond film layer 4 is cooled from the second preparation temperature to room temperature is calculated, the second stress is opposite to the first stress, and the difference between the second stress and the first stress is less than or equal to 1.5 GPa.

[0100] Before the preparation of the diamond film layer 4, the second stress generated between the diamond film layer 4 and the copper substrate 1 when the diamond film layer 4 is cooled from the second preparation temperature to room temperature can be simulated by computer simulation or theoretical calculation based on the preparation process parameters, the second stress calculation formula and the moment balance formula, and it is evaluated whether it is less than or equal to 11 GPa, and the second stress is opposite to the first stress, and the difference between the second stress and the first stress is less than or equal to 1.5 GPa. If the simulation result meets the requirements, subsequent preparation process operations are performed. In addition, the second stress calculation formula and the moment balance formula can be referred to as described above, and a detailed description is omitted here.

[0101] S700, according to the type of diamond film layer 4 and the corresponding preparation process parameters, the diamond film layer 4 is prepared on the second surface of the copper substrate.

[0102] By selecting the type of diamond film layer 4 and corresponding preparation process parameters, the diamond film layer 4 of the required thickness is prepared on the second surface of the copper base material 1, so that the second stress generated when the copper base material 1 is cooled is opposite to the direction of the first stress, and the difference is less than or equal to 1.5GPa.

[0103] From the above technical solutions, it can be seen that the present application provides another preparation method of the copper-based diamond composite material 100. The method selects the type of the stress buffer layer 5 and the diamond film layer 4 and corresponding preparation process parameters, calculates the first stress generated when the stress buffer layer 5 is cooled and the second stress generated when the diamond film layer 4 is cooled, and calculates the size and direction of the stress generated when the copper base material 1 is cooled, so that the first stress between the stress buffer layer 5 and the copper base material 1 formed on the first surface of the copper base material 1 and the second stress between the diamond film layer 4 and the copper base material 1 formed on the second surface of the copper base material 1 form a bidirectional offset, reduce the stress difference generated between the substrate layer structures, and realize low warpage of the copper-based diamond composite material 100, and the interface is not easy to debond or crack.

[0104] Please refer to Figure 3 , Figure 3 is a flowchart of a preparation method of a copper-based diamond composite material 100 according to another embodiment of the present application. The preparation method of the copper-based diamond composite material 100 includes steps S110, S111, S120 and S130, and the specific steps are substantially the same as those in Figure 1 The difference is that the present embodiment further includes step S111:

[0105] S111, the first surface and the second surface of the copper base material 1 are pretreated.

[0106] In yet some embodiments, a method for pre-treatment is provided, in particular, the first surface and the second surface of the copper substrate 1 are mechanically polished to a surface roughness Ra≤10 μm, for example, the surface roughness can be 1 μm, 3 μm, 4 μm, 5 μm, 8 μm and 10 μm, etc., to provide a uniform substrate for the subsequent formation of the stress buffer layer 5 and the diamond film layer 4; the first surface and the second surface of the copper substrate 1 are polished with diamond micro-powder particles having a particle size of 0.1 μm-50 μm, for example, the particle size of the diamond micro-powder particles can be 0.1 μm, 1 μm, 2 μm, 5 μm, 6 μm, 10 μm, 20 μm, 35 μm, 40 μm and 50 μm, etc., the polishing time is 5 min-30 min, for example, the polishing time can be 5 min, 6 min, 8 min, 10 min, 12 min, 15 min, 16 min, 18 min, 20 min, 25 min and 30 min, etc., which can improve the mechanical anchoring effect of the diamond film layer 4 and the copper substrate 1 and enhance the interfacial bonding strength; the copper substrate 1 is ultrasonically cleaned with deionized water and ethanol in sequence, the cleaning time is 10 min-100 min, for example, the cleaning time can be 10 min, 15 min, 18 min, 20 min, 25 min, 30 min, 40 min, 60 min, 85 min and 100 min, etc., and then the surface is blown dry with N2 or Ar to remove the metal debris and organic pollutants and other impurities remaining during the polishing and polishing process; the copper substrate 1 is treated with an argon plasma etching machine, the power range is 200 W-400 W, for example, the power can be 200 W, 210 W, 220 W, 230 W, 280 W, 300 W, 330 W, 370 W and 400 W, etc., the treatment time is 5 min-15 min, for example, the treatment time can be 5 min, 6 min, 8 min, 10 min, 13 min and 15 min, etc., to remove the surface oxide layer, expose copper atoms and significantly improve the surface activity of the copper substrate 1, to provide clean and high-activity nucleation sites for the subsequent formation of the stress buffer layer 5 and the diamond film layer 4.

[0107] Please refer to Figure 4 , Figure 4 is a flowchart of the method for preparing the copper-based diamond composite material 100 provided in some embodiments of the present application. The method for preparing the diamond copper composite material substrate 100 includes steps S110, S111, S120, S130 and S131, and the specific steps are substantially the same as those in Figure 3 The difference is that the present embodiment further includes step S131:

[0108] S131, removing the stress buffer layer 5.

[0109] Wherein, since the first stress and the second stress are generated in the process of cooling from the preparation temperature to the room temperature, and the copper-based diamond composite material 100 has been cooled and shaped after the preparation of the diamond film layer 4, the removal of the stress buffer layer 5 will not cause the warping and the interface cracking of the copper-based diamond composite material 100 at this time. Therefore, after the step of preparing the diamond film layer 4 on the second surface of the copper base material 1, the copper-based diamond composite material 100 without the stress buffer layer 5 and with low warping and interface cracking can be obtained by removing the stress buffer layer 5. The removal of the stress buffer layer 5 can reduce the interface thermal resistance between the stress buffer layer 5 and the copper base material 1 and the thermal resistance of the stress buffer layer 5 itself, and the exposed copper base material 1 can reduce the contact thermal resistance with the heat source after polishing, so that the overall heat transfer effect will be better.

[0110] In some other embodiments, a method for removing the stress buffer layer 5 is provided. Specifically, the diamond film layer 4 of the copper-based diamond composite material 100 is fixed on a clamp with an adhesive, and the clamp is placed on a grinding machine, for example, the grinding machine can be a COBORN PL5 type grinding machine or its equivalent device, and the outer surface of the stress buffer layer 5 is used as the surface to be ground. The grinding time is set to 30 min to 40 min, for example, the grinding time can be 30 min, 31 min, 33 min, 35 min, 37 min and 40 min, etc., the pressure is 0.2 MPa to 0.4 MPa, for example, the pressure can be 0.2 MPa, 0.3 MPa and 0.4 MPa, etc., the rotation speed is 180 r / min to 220 r / min, for example, the rotation speed can be 180 r / min, 185 r / min, 190 r / min, 200 r / min, 210 r / min and 220 r / min, etc., and the grinding operation is performed to remove the stress buffer layer 5. After the grinding is completed, the clamp and the copper base material 1 with the diamond film layer 4 on the second surface are placed together on a heating table, and the temperature of the heating table is 280℃ to 320℃, for example, the temperature can be 280℃, 282℃, 290℃, 295℃, 300℃, 310℃, 316℃ and 320℃, etc., so that the adhesive is softened and the copper base material 1 with the diamond film layer 4 on the second surface is separated from the clamp. After the separation, the copper base material 1 with the diamond film layer 4 is ultrasonically cleaned with anhydrous ethanol, and the cleaning time is 20 min to 40 min, for example, the cleaning time can be 20 min, 22 min, 23 min, 26 min, 30 min, 35 min and 40 min, etc., so as to completely remove the adhesive remaining on the surface of the diamond film layer 4, as shown in FIG. 6, and the layer structure without the stress buffer layer 5 is obtained. Figure 18

[0111] Please refer to Figure 5 , Figure 5 ​is a flowchart of a preparation method of the copper-based diamond composite material 100 provided by some embodiments of the present application. The preparation method of the copper-based diamond composite material 100 includes steps S110, S111, S112, S120 and S130, and the specific steps are substantially the same as those in the method shown in Figure 3 The difference between the two methods is that the present embodiment further includes step S112:

[0112] S112, plating a transition layer on the first surface and / or the second surface of the copper base material.

[0113] The transition layer can significantly improve the wettability between copper and diamond. By introducing titanium, chromium or other metals or titanium carbide, titanium nitride or other compounds as the transition layer, these materials can chemically react with the carbon atoms on the surface of the diamond to form a stable carbide layer, thereby effectively enhancing the bonding strength between the two.

[0114] The transition layer can be at least one of titanium, chromium, tungsten, tantalum, titanium carbide, tungsten carbide, titanium nitride, tungsten nitride, and chromium nitride.

[0115] In some embodiments, a method for preparing a transition layer is provided. Specifically, the transition layer is prepared by magnetron sputtering and has a thickness of 50 nm to 800 nm, for example, values ​​of 50 nm, 70 nm, 80 nm, 85 nm, 90 nm, 100 nm, 200 nm, 500 nm, 660 nm, and 800 nm. Specific process parameters are: the target material is the material of the transition layer to be deposited; DC mode is selected in the magnetron sputtering equipment; and the power is 100 kW. Power ratings range from W to 250W, for example, power values ​​can be 100W, 130W, 150W, 160W, 170W, 180W, 200W, and 250W, etc.; air pressure ranges from 0.5Pa to 3.0Pa, for example, air pressure values ​​can be 0.5Pa, 0.7Pa, 0.8Pa, 1.0Pa, 1.1Pa, 1.2Pa, 1.4Pa, 2.0Pa, 2.6Pa, and 3.0Pa, etc.; Ar flow rate ranges from 50 sccm to 150 sccc. For example, the Ar flow rate can be 50 sccm, 55 sccm, 60 sccm, 75 sccm, 80 sccm, 100 sccm, 110 sccm, and 150 sccm, etc., and the cavity temperature can be 25℃~200℃, for example, the cavity temperature can be 25℃, 50℃, 55℃, 75℃, 80℃, 90℃, 100℃, 130℃, 150℃, 170℃, and 200℃, etc., and the matrix temperature can be 100℃~5 00℃, for example, the substrate temperature can be 100℃, 120℃, 150℃, 200℃, 250℃, 280℃, 380℃, 400℃, 480℃ and 500℃, etc., and the deposition time is 10min to 300min, for example, the deposition time can be 10min, 13min, 16min, 20min, 22min, 25min, 60min, 150min, 220min and 300min, etc.

[0116] The structure of the copper-based diamond composite material 100 of the present invention is described below.

[0117] This invention provides a method according to Figure 1 A schematic diagram of the structure of the copper-based diamond composite material 100 prepared by the above method is shown below. Figure 17 As shown, it includes a copper substrate 1, a stress buffer layer 5 on the first surface of the copper substrate 1, and a diamond film layer 4 on the second surface of the copper substrate 1. The structure and connection relationship of the copper substrate 1, the diamond film layer 4, and the stress buffer layer 5 can be referred to the previous text, and will not be repeated here.

[0118] The copper-based diamond composite material 100 prepared by the preparation method of the present application has the stress buffer layer 5 arranged on the first surface of the copper base material 1 and the diamond film layer 4 arranged on the second surface, and the first stress generated between the stress buffer layer 5 and the copper base material 1 when the stress buffer layer 5 is formed is counteracted by the second stress generated between the diamond film layer 4 and the copper base material 1 when the diamond film layer 4 is formed, so that the copper-based diamond composite material 100 has low warping and the interface is not easy to debond and crack. In addition, the stress buffer layer 5 can provide wear resistance, corrosion resistance and electrical insulation functions as a protective layer, and the high thermal conductivity of the diamond film layer 4 can improve the overall heat dissipation performance, so that the material is suitable for application in electronic products and semiconductor devices which have high requirements for environmental tolerance and heat dissipation effect.

[0119] The present application provides a copper-based diamond composite material 100 prepared by the preparation method of the present application. Figure 4 The structure diagram of the copper-based diamond composite material 100 prepared by the preparation method of the present application is shown in FIG. 1. As shown in the figure, it comprises a copper base material 1 and a diamond film layer 4 on the second surface. The structure and connection relationship of the copper base material 1 and the diamond film layer 4 can be referred to the foregoing description, and will not be repeated here. Figure 18

[0120] The copper-based diamond composite material 100 prepared by the preparation method of the present application firstly arranges the stress buffer layer 5 on the first surface of the copper base material 1 and the diamond film layer 4 on the second surface, and counteracts the first stress generated between the stress buffer layer 5 and the copper base material 1 when the stress buffer layer 5 is formed by the second stress generated between the diamond film layer 4 and the copper base material 1 when the diamond film layer 4 is formed; secondly, after the diamond film layer 4 is arranged on the second surface, the stress buffer layer 5 is removed, so that the copper-based diamond composite material 100 does not contain the stress buffer layer 5 and has low warping and the interface is not easy to crack. Removing the stress buffer layer 5 can reduce the interface thermal resistance between the stress buffer layer 5 and the copper base material 1 and the thermal resistance of the stress buffer layer 5 itself, and the exposed copper base material 1 can reduce the contact thermal resistance with the heat source after polishing, so that the overall heat transfer effect will be better. Therefore, the material is especially suitable for application in products which have high requirements for heat dissipation effect but not high requirements for environmental tolerance.

[0121] The present application provides a copper-based diamond composite material 100 prepared by the preparation method of the present application. Figure 5 The structure diagram of the copper-based diamond composite material 100 prepared by the preparation method of the present application is shown in FIG. 1. As shown in the figure, it comprises a copper base material 1 and a diamond film layer 4 on the second surface. The structure and connection relationship of the copper base material 1 and the diamond film layer 4 can be referred to the foregoing description, and will not be repeated here. Figure 19 The present application provides a copper-based diamond composite material 100 prepared by the preparation method of the present application.

[0122] The structure diagram of the copper-based diamond composite material 100 prepared by the preparation method of the present application is shown in FIG. 1. As shown in the figure, it comprises a copper base material 1 and a diamond film layer 4 on the second surface. The structure and connection relationship of the copper base material 1 and the diamond film layer 4 can be referred to the foregoing description, and will not be repeated here. Figure 5 ​The copper-based diamond composite material 100 prepared by the preparation method has a first transition layer 3 with a thermal expansion coefficient of 10 x 10 -6 / K, which is between the copper base material 1 (17 x 10 -6 / K) and the stress buffer layer 5 (4 x 10 -6 / K), and the interface thermal stress between the stress buffer layer 5 and the copper base material 1 can be relieved by gradient design; the second transition layer 2 also has a thermal expansion coefficient of 10 x 10 -6 / K, which is between the copper base material 1 (17 x 10 -6 / K) and the diamond film layer 4 (1 x 10 -6 / K), so as to further reduce the interface thermal stress between the diamond film layer 4 and the copper base material 1, reduce film layer defects, and enhance the interface bonding strength, so that the residual thermal stress distribution of the entire copper-based diamond composite material 100 is homogenized, thereby improving the structural reliability.

[0123] The thickness of the copper base material 1, the area of the first surface and the second surface, the type and thickness of the stress buffer layer 5, the type and thickness of the diamond film layer 4, and the type and thickness of the first transition layer 3 and the second transition layer 2 in the structure of the copper-based diamond composite material 100 can be referred to the description above, and will not be repeated here.

[0124] The preparation method of the copper-based diamond composite material 100 of the embodiments of the present application will be described below through specific examples.

[0125] Example 1

[0126] Please refer to Figure 1 , first prepare an oxygen-free copper sheet with a length of 25 mm, a width of 20 mm, and a height of 0.5 mm, the thickness of the copper base material 1 is 0.5 mm, the area of the first surface and the second surface of the copper base material 1 is 500 mm 2 , and the area to thickness ratio of the copper base material 1 is 1000:1;

[0127] The copper base material 1 is placed in a hot wire chemical vapor deposition device, the furnace pressure is set to 1000 Pa, the power of a single hot wire is 1.5 kW, the first preparation temperature is controlled at 700°C, the distance between the hot wire and the substrate is 12 mm, the H2 flow is 500 sccm, the CH4 flow is 25 sccm, the first preparation time is 5 h, and a nanocrystalline diamond film (one kind of stress buffer layer 5) is prepared on the first surface of the copper base material 1, and the thickness of the stress buffer layer 5 is controlled to be 5 μm;

[0128] After the preparation, the temperature is decreased at a rate of 20℃ / h to room temperature, and then the layer structure is taken out; then the second surface is upward, and the layer structure is put into the hot filament chemical vapor deposition device again, the furnace pressure is set to 4000 Pa, the power of a single hot filament is 2.0 kW, the second preparation temperature is controlled at 800℃, the distance between the hot filament and the substrate is 10 mm, the flow rate of H2 is 500 sccm, the flow rate of CH4 is 10 sccm, and the second preparation time is 8 h, so that the microcrystalline diamond film (one of the diamond film layers 4) is prepared on the second surface of the copper substrate 1, and the thickness of the diamond film layer 4 is controlled to be 5.5 μm;

[0129] After the preparation, the temperature is decreased at a rate of 15℃ / h to room temperature, and then the layer structure is taken out, so that the copper-based diamond composite material 100 with low warping degree is obtained, and the warping radius is 395.028 mm.

[0130] Example 2

[0131] Please refer to Figure 2 First, an oxygen-free copper sheet with a length of 25 mm, a width of 20 mm, and a height of 0.5 mm is prepared, the thickness of the copper substrate 1 is 0.5 mm, the area of the first surface and the second surface of the copper substrate 1 is 500 mm 2 , and the ratio of the area to the thickness of the copper substrate 1 is 1000:1;

[0132] The stress buffer layer 5 on the first surface of the copper substrate 1 is selected to be a nanodiamond film, and the preparation process selected is hot filament chemical vapor deposition, and the parameters of the hot filament chemical vapor deposition are that the furnace pressure is 1000 Pa, the power of a single hot filament is 1.5 kW, the first preparation temperature is controlled at 700℃, the distance between the hot filament and the substrate is 12 mm, the flow rate of H2 is 500 sccm, the flow rate of CH4 is 25 sccm, the first preparation time is 5 h, and the thickness of the nanodiamond film is controlled to be 5 μm;

[0133] The first stress generated by the stress buffer layer 5 from the first preparation temperature to room temperature with the copper substrate 1 is calculated to be 5.08 GPa;

[0134] According to the type and preparation process parameters of the selected stress buffer layer 5, the stress buffer layer 5 is prepared on the first surface of the copper substrate 1;

[0135] The type of the diamond film layer 4 on the second surface of the copper substrate 1 is selected to be a microcrystalline diamond film, and the preparation process selected is hot filament chemical vapor deposition, and the parameters of the hot filament chemical vapor deposition are that the furnace pressure is 4000 Pa, the power of a single hot filament is 2.0 kW, the second preparation temperature is controlled at 800℃, the distance between the hot filament and the substrate is 10 mm, the flow rate of H2 is 500 sccm, the flow rate of CH4 is 10 sccm, the second preparation time is 8 h, and the thickness of the microcrystalline diamond film is controlled to be 5.5 μm;

[0136] The second stress generated by the diamond film layer 4 from the second preparation temperature to room temperature with the copper substrate 1 is 5.17 GPa, and the difference between the second stress and the first stress is 0.09 GPa, which is less than 1.5 GPa;

[0137] According to the selected diamond film layer 4 and the preparation process parameters, the diamond film layer 4 is prepared on the second surface of the copper substrate 1;

[0138] The copper-based diamond composite material 100 with low warpage is obtained, and the warpage radius is 395.028 mm.

[0139] Example 3

[0140] The steps are substantially the same as those of Example 1, except that Figure 5 The first surface and the second surface of the copper substrate 1 are pretreated, and a transition layer is plated on the first surface and the second surface of the copper substrate 1. The specific preparation method is as follows:

[0141] Please refer to Figure 5 First, prepare an oxygen-free copper sheet with a length of 25 mm, a width of 20 mm, and a height of 0.5 mm. The thickness of the copper substrate 1 is 0.5 mm, and the area of the first surface and the second surface of the copper substrate 1 is 500 mm 2 The ratio of the area to the thickness of the copper substrate 1 is 1000:1;

[0142] Then, the first surface and the second surface of the copper substrate 1 are pretreated: the first surface and the second surface of the copper substrate 1 are mechanically polished to a surface roughness Ra≤3 μm; 5 μm particle size diamond powder particles are used to polish the first surface and the second surface of the copper substrate 1, and the polishing time is 15 min; the first surface and the second surface of the copper substrate 1 are cleaned with deionized water and ethanol respectively, and the cleaning time is 30 min, and the surface is dried with N2; the first surface and the second surface of the copper substrate 1 are treated by using an argon plasma etching machine with a power of 200 W, and the treatment time is 10 min, to obtain the pretreated copper substrate 1;

[0143] After the pretreatment is completed, a transition layer is plated on the first surface and the second surface of the copper substrate 1: the copper substrate 1 is placed in a magnetron sputtering device, the power is set to 200 W, the gas pressure is 1.2 Pa, the Ar flow rate is 80 sccm, the target material is titanium, the cavity temperature is controlled at 150 ℃, the substrate temperature is 500 ℃, and the deposition time is 20 min. A titanium film is plated on the first surface of the copper substrate 1 as a first transition layer 3, and a titanium film is plated on the second surface as a second transition layer 2, and the thicknesses are both 80 nm;

[0144] After plating the transition layer, the copper substrate 1 is placed in a hot-wire chemical vapor deposition device, the furnace pressure is set to 1000 Pa, the power of a single hot wire is 1.5 kW, the first preparation temperature is controlled at 700℃, the distance between the hot wire and the substrate is 12 mm, the H2 flow rate is 500 sccm, the CH4 flow rate is 25 sccm, and the first preparation time is 5 h, so as to prepare a nanocrystalline diamond film (one of the stress buffer layers 5) on the first surface of the copper substrate 1, and the thickness of the stress buffer layer 5 is controlled to be 5 μm;

[0145] After the preparation is completed, the temperature is lowered at a rate of 20℃ / h, and after being lowered to room temperature, the layer structure is taken out; then the second surface is upwardly placed again into the hot-wire chemical vapor deposition device, the furnace pressure is set to 4000 Pa, the power of a single hot wire is 2.0 kW, the second preparation temperature is controlled at 800℃, the distance between the hot wire and the substrate is 10 mm, the H2 flow rate is 500 sccm, the CH4 flow rate is 10 sccm, and the second preparation time is 8 h, so as to prepare a microcrystalline diamond film (one of the diamond film layers 4) on the second surface of the copper substrate 1, and the thickness of the diamond film layer 4 is controlled to be 5.5 μm;

[0146] After the preparation is completed, the temperature is lowered at a rate of 15℃ / h, and after being lowered to room temperature, the layer structure is taken out, and the copper-based diamond composite material 100 with low warping degree is obtained, and the warping radius is 395.028 mm.

[0147] Example 4

[0148] Please refer to Figure 1 First, an oxygen-free copper sheet with a length of 30 mm, a width of 30 mm, and a height of 0.8 mm is prepared, the thickness of the copper substrate 1 is 0.8 mm, the area of the first surface and the second surface of the copper substrate 1 is 900 mm 2 The ratio of the area to the thickness of the copper substrate 1 is 1125:1;

[0149] The copper substrate 1 is placed in a filtered cathode arc device, the pressure in the adjusting cavity is set to 8 Pa, the arc current is 120 A, the substrate bias is -80 V, the first preparation temperature is controlled at 300℃, the distance between the arc target material and the substrate is 100 mm, the Ar flow rate is 600 sccm, the H2 flow rate is 60 sccm, and the first preparation time is 5 h, so as to obtain a diamond-like film on the first surface of the copper substrate 1 (one of the stress buffer layers 5), and the thickness of the stress buffer layer 5 is controlled to be 12 μm;

[0150] After the preparation, the temperature is decreased at a rate of 18℃ / h to room temperature, and then the layer structure is taken out; subsequently, the second surface is upward, and the layer structure is placed into the hot filament chemical vapor deposition device again, the furnace pressure is set to 4500 Pa, the power of a single hot filament is 2.1 kW, the second preparation temperature is controlled at 850℃, the distance between the hot filament and the substrate is 9.5 mm, the H2 flow is 550 sccm, the CH4 flow is 12 sccm, and the second preparation time is 10 h, so that the micrometer crystal diamond film (one of the diamond film layers 4) is prepared on the second surface of the copper substrate 1, and the thickness of the diamond film layer 4 is controlled to be 8 μm;

[0151] After the preparation, the temperature is decreased at a rate of 10℃ / h to room temperature, and then the copper-based diamond composite material 100 with low warping degree is obtained, and the warping radius is 138 mm.

[0152] Example 5

[0153] The steps are basically the same as those of Example 1, except that Figure 5 The first surface and the second surface of the copper substrate 1 are pretreated, and a transition layer is plated on the first surface and the second surface of the copper substrate 1, and the specific preparation method is as follows:

[0154] Please refer to Figure 5 First, an oxygen-free copper sheet with a radius of 20 mm and a thickness of 0.3 mm is prepared, the thickness of the copper substrate 1 is 0.3 mm, and the area of the first surface and the second surface of the copper substrate 1 is 1256 mm 2 The ratio of the area to the thickness of the copper substrate 1 is 4186:1;

[0155] Then, the first surface and the second surface of the copper substrate 1 are pretreated: the first surface and the second surface of the copper substrate 1 are mechanically polished to a surface roughness Ra≤3 μm; 5 μm particle size diamond powder particles are used to polish the first surface and the second surface of the copper substrate, and the polishing time is 16 min; deionized water and ethanol are used to ultrasonically clean the first surface and the second surface of the copper substrate, respectively, and the cleaning time is 25 min, and the surface is dried by N2; the first surface and the second surface of the copper substrate are treated by using an argon plasma etching machine with a power of 200 W, and the treatment time is 15 min, to obtain the pretreated copper substrate 1;

[0156] After the pretreatment is completed, a transition layer is plated on the first surface and the second surface of the copper substrate 1: the copper substrate 1 is placed in a magnetron sputtering device, the power is set to 180 W, the gas pressure is 1.1 Pa, the Ar flow is 75 sccm, the target material is titanium, the cavity temperature is controlled to be 200℃, the substrate temperature is 480℃, and the deposition time is 25 min, so that a titanium film is plated on the first surface of the copper substrate 1 as a first transition layer 3, and a titanium film is plated on the second surface as a second transition layer 2, and the thicknesses of the two are both 85 nm;

[0157] After plating the transition layer, the copper substrate 1 is placed in a hot-wire chemical vapor deposition device, the furnace pressure is set to 900 Pa, the power of a single hot wire is 1.4 kW, the first preparation temperature is controlled at 680℃, the distance between the hot wire and the substrate is 12.5 mm, the H2 flow rate is 500 sccm, the CH4 flow rate is 25 sccm, and the first preparation time is 5 h. The nanocrystalline diamond film (one of the stress buffer layers 5) is prepared on the first surface of the copper substrate 1, and the thickness of the stress buffer layer 5 is controlled to be 5 μm;

[0158] After the preparation is completed, the temperature is lowered at a rate of 20℃ / h, and after being lowered to room temperature, the layer structure is taken out; then the second surface is upwardly placed again into the hot-wire chemical vapor deposition device, the furnace pressure is set to 900 Pa, the power of a single hot wire is 1.4 kW, the second preparation temperature is controlled at 680℃, the distance between the hot wire and the substrate is 12.5 mm, the H2 flow rate is 500 sccm, the CH4 flow rate is 25 sccm, and the second preparation time is 5 h. The nanocrystalline diamond film (one of the diamond film layers 4) is prepared on the second surface of the copper substrate 1, and the thickness of the diamond film layer 4 is controlled to be 5 μm;

[0159] After the preparation is completed, the temperature is lowered at a rate of 20℃ / h, and after being lowered to room temperature, the layer structure is taken out; then the second surface is upwardly placed again into the hot-wire chemical vapor deposition device, the furnace pressure is set to 900 Pa, the power of a single hot wire is 1.4 kW, the second preparation temperature is controlled at 680℃, the distance between the hot wire and the substrate is 12.5 mm, the H2 flow rate is 500 sccm, the CH4 flow rate is 25 sccm, and the second preparation time is 5 h. The nanocrystalline diamond film (one of the diamond film layers 4) is prepared on the second surface of the copper substrate 1, and the thickness of the diamond film layer 4 is controlled to be 5 μm;

[0160] Example 6

[0161] The steps are substantially the same as those of Example 1, except that, referring to Figure 3 , the first surface and the second surface of the copper substrate 1 are pretreated, and the specific preparation method is as follows:

[0162] Please refer to Figure 3 , first prepare an oxygen-free copper sheet with a length of 20 mm, a width of 30 mm, and a height of 0.8 mm, the thickness of the copper substrate 1 is 0.8 mm, and the area of the first surface and the second surface of the copper substrate 1 is 600 mm 2 , the ratio of the area to the thickness of the copper substrate 1 is 750:1;

[0163] Then, the first surface and the second surface of the copper substrate 1 are pretreated: the first surface and the second surface of the copper substrate 1 are mechanically ground to a surface roughness Ra≤1 μm; 2 μm particle size diamond powder particles are used to grind the first surface and the second surface of the copper substrate 1, and the grinding time is 10 min; the first surface and the second surface of the copper substrate 1 are ultrasonically cleaned with deionized water and ethanol respectively, the cleaning time is 20 min, and the surface is blown dry with N2; the first surface and the second surface of the copper substrate 1 are treated by using an argon plasma etching machine with a power of 210 W, and the treatment time is 15 min, to obtain the pretreated copper substrate 1;

[0164] The copper substrate 1 is placed in a filtered cathodic arc device, the pressure in the adjustment chamber is set to 5 Pa, the arc current is 100 A, the substrate bias is -100 V, the first preparation temperature is controlled at 260℃, the distance between the arc target material and the substrate is 90 mm, the Ar flow rate is 720 sccm, the H2flow rate is 80 sccm, and the first preparation time is 6 h. A diamond-like film (one of the stress buffer layers 5) is obtained on the first surface of the copper substrate 1, and the thickness of the stress buffer layer 5 is controlled to be 13 μm.

[0165] After the preparation is completed, the temperature is lowered at a rate of 20℃ / h, and after being lowered to room temperature, the layer structure is taken out; then the second surface is upward, and the layer structure is placed again in the hot-wire chemical vapor deposition device, the furnace pressure is set to 1000 Pa, the power of a single hot wire is 1.5 kW, the second preparation temperature is controlled at 700℃, the distance between the hot wire and the substrate is 10.5 mm, the H2flow rate is 460 sccm, the CH4flow rate is 20 sccm, and the second preparation time is 6 h. A nanocrystalline diamond film (one of the diamond film layers 4) is prepared on the second surface of the copper substrate 1, and the thickness of the diamond film layer 4 is controlled to be 6 μm.

[0166] After the preparation is completed, the temperature is lowered at a rate of 20℃ / h, and after being lowered to room temperature, the layer structure is taken out; then the second surface is upward, and the layer structure is placed again in the hot-wire chemical vapor deposition device, the furnace pressure is set to 1000 Pa, the power of a single hot wire is 1.5 kW, the second preparation temperature is controlled at 700℃, the distance between the hot wire and the substrate is 10.5 mm, the H2flow rate is 460 sccm, the CH4flow rate is 20 sccm, and the second preparation time is 6 h. A nanocrystalline diamond film (one of the diamond film layers 4) is prepared on the second surface of the copper substrate 1, and the thickness of the diamond film layer 4 is controlled to be 6 μm.

[0167] Example 7

[0168] The steps are basically the same as those in Example 1, except that Figure 5 The first surface and the second surface of the copper substrate 1 are pretreated; and a transition layer is plated on the first surface and the second surface of the copper substrate 1. The specific preparation method is as follows:

[0169] Please refer to Figure 5 First, an oxygen-free copper sheet with a radius of 20 mm and a thickness of 0.3 mm is prepared, the thickness of the copper substrate 1 is 0.3 mm, and the area of the first surface and the second surface of the copper substrate 1 is 1256 mm 2 The ratio of the area to the thickness of the copper substrate 1 is 4186:1.

[0170] Then, the first surface and the second surface of the copper substrate 1 are pretreated: the first surface and the second surface of the copper substrate 1 are mechanically polished to a surface roughness Ra≤3 μm; 5 μm particle size diamond powder particles are used to polish the first surface and the second surface of the copper substrate 1, and the polishing time is 8 min; deionized water and ethanol are used to ultrasonically clean the first surface and the second surface of the copper substrate 1, respectively, and the cleaning time is 10 min, and the surface is blown dry with N2; an argon plasma etching machine with a power of 220 W is used to treat the first surface and the second surface of the copper substrate 1, and the treatment time is 15 min, to obtain the pretreated copper substrate 1.

[0171] After the pretreatment, a transition layer is plated on the first surface and the second surface of the copper substrate 1: the copper substrate 1 is placed in a magnetron sputtering device, the power is set to 170 W, the air pressure is 1.0 Pa, the Ar flow is 80 sccm, the target material is titanium, the cavity temperature is controlled to 50℃, the substrate temperature is 280℃, and the titanium film is deposited on the first surface of the copper substrate 1 as the first transition layer 3 and on the second surface of the copper substrate 1 as the second transition layer 2 for 22 min, and the thickness of the titanium film is 70 nm;

[0172] After the transition layer is plated, the copper substrate 1 is placed in a magnetron sputtering device, the target material is titanium, the Ar flow is set to 95 sccm, the CH4 flow is 5 sccm, the cavity air pressure is 1.0 Pa, the power is 100 W, the cavity temperature is 25℃, the first preparation temperature is controlled to 450℃, and the first preparation time is 15 h. The titanium carbide hard alloy film (one of the stress buffer layers 5) is prepared on the first surface of the copper substrate 1, and the thickness of the stress buffer layer 5 is controlled to be 20μm.

[0173] After the preparation is completed, the temperature is lowered at a rate of 10℃ / h, and after the temperature is lowered to room temperature, the layer structure is taken out; then the second surface is placed upward, and the hot wire chemical vapor deposition device is used again, the furnace pressure is set to 3800 Pa, the power of a single hot wire is 1.9kW, the second preparation temperature is controlled to 820℃, the distance between the hot wire and the substrate is 10mm, the H2 flow is 480sccm, the CH4 flow is 10sccm, and the second preparation time is 10h. The micron crystalline diamond film (one of the diamond film layers 4) is prepared on the second surface of the copper substrate 1, and the thickness of the diamond film layer 4 is controlled to be 10μm.

[0174] After the preparation is completed, the temperature is lowered at a rate of 10℃ / h, and after the temperature is lowered to room temperature, the layer structure is taken out; then the second surface is placed upward, and the hot wire chemical vapor deposition device is used again, the furnace pressure is set to 3800 Pa, the power of a single hot wire is 1.9kW, the second preparation temperature is controlled to 820℃, the distance between the hot wire and the substrate is 10mm, the H2 flow is 480sccm, the CH4 flow is 10sccm, and the second preparation time is 10h. The micron crystalline diamond film (one of the diamond film layers 4) is prepared on the second surface of the copper substrate 1, and the thickness of the diamond film layer 4 is controlled to be 10μm.

[0175] Example 8

[0176] The steps are basically the same as those of Example 1, except that, referring to Figure 5 , the first surface and the second surface of the copper substrate 1 are pretreated; and a transition layer is plated on the first surface and the second surface of the copper substrate 1, and the specific preparation method is as follows:

[0177] Please refer to Figure 5 , first prepare an oxygen-free copper piece with a length of 20mm, a width of 20mm, and a height of 2mm, the thickness of the copper substrate 1 is 2mm, and the area of the first surface and the second surface of the copper substrate 1 is 400mm 2 , the ratio of the area to the thickness of the copper substrate 1 is 200:1;

[0178] Then the first surface and the second surface of the copper substrate 1 are pretreated: the first surface and the second surface of the copper substrate 1 are mechanically polished to a surface roughness Ra≤1 μm; the first surface and the second surface of the copper substrate 1 are polished using 5 μm particle size diamond powder particles, and the polishing time is 12 min; the first surface and the second surface of the copper substrate 1 are ultrasonically cleaned using deionized water and ethanol respectively, and the cleaning time is 18 min, and the surface is dried with N2; the first surface and the second surface of the copper substrate 1 are treated using an argon plasma etching machine with a power of 230 W, and the treatment time is 15 min, to obtain the pretreated copper substrate 1;

[0179] After the pretreatment is completed, a transition layer is plated on the first surface and the second surface of the copper substrate 1: the copper substrate 1 is placed in a magnetron sputtering device, the power is set to 200 W, the gas pressure is 0.8 Pa, the Ar flow is 110 sccm, the target material is titanium, the cavity temperature is controlled at 100°C, the substrate temperature is 380°C, and the deposition time is 25 min. The first surface of the copper substrate 1 is plated as a first transition layer 3, and the second surface is plated with a titanium film as a second transition layer 2, both with a thickness of 90 nm.

[0180] After plating the transition layer, the copper substrate 1 is placed into a microwave plasma chemical vapor deposition device, the microwave power is set to 3 KW, the cavity gas pressure is 2800 Pa, the first preparation temperature is controlled at 660°C, the H2 flow is 200 sccm, the CH4 flow is 10 sccm, and the first preparation time is 5 h. A nanocrystalline diamond film (one of the stress buffer layers 5) is prepared on the first surface of the copper substrate, and the thickness of the stress buffer layer 5 is controlled to be 5 μm.

[0181] After the preparation is completed, the temperature is lowered at a rate of 30°C / h, and after being lowered to room temperature, the layer structure is taken out; then the second surface is upward, and the microwave plasma chemical vapor deposition device is used again, the microwave power is set to 6 KW, the cavity gas pressure is 20000 Pa, the first preparation temperature is controlled at 800°C, the H2 flow is 400 sccm, the CH4 flow is 8 sccm, and the first preparation time is 7 h. A micron crystalline diamond film (one of the diamond film layers 4) is prepared on the second surface of the copper substrate, and the thickness of the diamond film layer 4 is controlled to be 4.8 μm.

[0182] After the preparation is completed, the temperature is lowered at a rate of 20°C / h, and after being lowered to room temperature, it is taken out, obtaining a copper-based diamond composite material 100 with low warping degree, and the warping radius is 180 mm.

[0183] Example 9

[0184] The steps are basically the same as those of Example 1, except that Figure 4 The first surface and the second surface of the copper substrate 1 are pretreated; and the stress buffer layer 5 is removed, and the specific preparation method is as follows:

[0185] Please refer toFigure 4 First, an oxygen-free copper piece with a length of 20 mm, a width of 30 mm, and a height of 0.8 mm is prepared, the thickness of the copper base material 1 is 0.8 mm, and the area of the first surface and the second surface of the copper base material 1 is 600 mm 2 The ratio of the area to the thickness of the copper base material 1 is 750:1.

[0186] Then, the first surface and the second surface of the copper base material 1 are pretreated: the first surface and the second surface of the copper base material 1 are mechanically polished to a surface roughness Ra≤1 μm; the first surface and the second surface of the copper base material 1 are polished using 2 μm particle size diamond powder particles, and the polishing time is 10 min; the first surface and the second surface of the copper base material 1 are ultrasonically cleaned with deionized water and ethanol, respectively, and the cleaning time is 20 min, and the surface is blown dry with N2; the first surface and the second surface of the copper base material 1 are treated using an argon plasma etching machine with a power of 210 W, and the treatment time is 15 min, to obtain the pretreated copper base material 1.

[0187] The copper base material 1 is placed in a filtered cathode arc device, the adjustment cavity pressure is set to 5 Pa, the arc current is 100 A, the substrate bias is -100 V, the first preparation temperature is controlled at 260°C, the distance between the arc target material and the base material is 90 mm, the Ar flow rate is 720 sccm, the H2 flow rate is 80 sccm, and the first preparation time is 6 h, to obtain a diamond-like film (one of the stress buffer layers 5) on the first surface of the copper base material 1, and the thickness of the stress buffer layer 5 is controlled to be 13 μm.

[0188] After the preparation is completed, the temperature is lowered at a rate of 20°C / h, and after being lowered to room temperature, the layer structure is taken out; then the second surface is upward, and the hot wire chemical vapor deposition device is placed again, the furnace pressure is set to 1000 Pa, the power of a single hot wire is 1.5 kW, the second preparation temperature is controlled at 700°C, the distance between the hot wire and the substrate is 10.5 mm, the H2 flow rate is 460 sccm, the CH4 flow rate is 20 sccm, and the second preparation time is 6 h, to prepare a nanocrystalline diamond film (one of the diamond film layers 4) on the second surface of the copper base material 1, and the thickness of the diamond film layer 4 is controlled to be 6 μm.

[0189] After the preparation is completed, the temperature is decreased at a rate of 20℃ / h to room temperature, and then the layer structure is taken out; subsequently, the diamond film layer 4 of the layer structure is fixed on a clamp with an adhesive, and the clamp is placed on a COBORN PL5 type grinder, so that the outer surface of the stress buffer layer 5 serves as a surface to be ground; the grinding time is set to 40 min, the pressure is 0.3 MPa, and the rotation speed is 200 r / min, and the grinding operation is performed to remove the stress buffer layer 5; after the grinding is completed, the clamp and the layer structure are placed together on a heating table, and the temperature of the heating table is 300℃, so that the adhesive is softened, and then the layer structure is separated from the clamp; after the separation, the layer structure is ultrasonically cleaned with anhydrous ethanol for 30 min, so that the adhesive remaining on the surface of the diamond film layer 4 is completely removed, and a copper-based diamond composite material 100 without the stress buffer layer 5 and with low warping is obtained, and the warping radius is 177 mm.

[0190] Comparative Example 1

[0191] First, an oxygen-free copper sheet with a length of 25 mm, a width of 20 mm, and a height of 0.5 mm is prepared, the thickness of the copper substrate is 0.5 mm, the area of the first surface and the second surface of the copper substrate is 500 mm 2 , and the ratio of the area of the copper substrate to the thickness is 1000:1;

[0192] Then, the first surface and the second surface of the copper substrate 1 are pretreated: the first surface and the second surface of the copper substrate are mechanically ground to a surface roughness Ra≤3μm; the first surface and the second surface of the copper substrate are ground using 5μm particle size diamond powder particles, and the grinding time is 15 min; the first surface and the second surface of the copper substrate are ultrasonically cleaned with deionized water and ethanol respectively, and the cleaning time is 30 min, and the surface is dried with N2; the first surface and the second surface of the copper substrate are treated with an argon plasma etching machine with a power of 200W, and the treatment time is 10 min, to obtain a pretreated copper substrate;

[0193] After the pretreatment is completed, a transition layer is plated on the first surface and the second surface of the copper substrate: the copper substrate is placed in a magnetron sputtering device, the power is set to 200W, the gas pressure is 1.2Pa, the Ar flow rate is 80sccm, the target material is titanium, the cavity temperature is controlled at 150℃, and the substrate temperature is 500℃, and the titanium film is deposited on the first surface and the second surface of the copper substrate 1 for 20 min, and the thickness is 80nm;

[0194] After plating the transition layer, the copper substrate is placed in a hot wire chemical vapor deposition device, the furnace pressure is set to 4000Pa, the power of a single hot wire is 2.0kW, the deposition temperature is controlled at 800℃, the distance between the hot wire and the substrate is 10mm, the H2flow rate is 500sccm, the CH4flow rate is 10sccm, and the deposition time is 8h, to prepare a microcrystalline diamond film on the first surface of the copper substrate;

[0195] After the deposition, the temperature is decreased at a rate of 15℃ / h to room temperature, and the copper-based diamond composite material is obtained, with a warping radius of 58.187mm.

[0196] Comparative Example 2

[0197] First, an oxygen-free copper sheet with a length of 25mm, a width of 20mm, and a height of 0.5mm is prepared, the thickness of the copper substrate is 0.5mm, the area of the first surface and the second surface of the copper substrate is 500mm 2 , and the ratio of the area of the copper substrate to the thickness is 1000:1;

[0198] Then, the first surface and the second surface of the copper substrate are pretreated: the first surface and the second surface of the copper substrate are mechanically polished to a surface roughness Ra≤3μm; the first surface and the second surface of the copper substrate are polished using 5μm particle size diamond powder particles, and the polishing time is 15min; the first surface and the second surface of the copper substrate are ultrasonically cleaned with deionized water and ethanol respectively, and the cleaning time is 30min, and the surface is dried with N2; the first surface and the second surface of the copper substrate are treated using an argon plasma etching machine with a power of 200W, and the treatment time is 10min, to obtain the pretreated copper substrate;

[0199] After the pretreatment is completed, a transition layer is plated on the first surface and the second surface of the copper substrate: the copper substrate is placed in a magnetron sputtering device, the power is set to 200W, the gas pressure is 1.2Pa, the Ar flow rate is 80sccm, the target material is titanium, the cavity temperature is controlled at 150℃, the substrate temperature is 500℃, and the deposition time is 20min, to plate a titanium film on the first surface of the copper substrate 1 and a titanium film on the second surface, both with a thickness of 80nm;

[0200] After plating the transition layer, the copper substrate is placed in a hot-wire chemical vapor deposition device, the furnace pressure is set to 1000Pa, the power of a single hot wire is 1.5kW, the deposition temperature is controlled at 700℃, the distance between the hot wire and the substrate is 12mm, the H2flow rate is 500sccm, the CH4flow rate is 25sccm, and the deposition time is 5h, to prepare a nanocrystalline diamond film on the first surface of the copper substrate;

[0201] After the deposition, the temperature is decreased at a rate of 20℃ / h to room temperature, and the copper-based diamond composite material is obtained, with a warping radius of 55.530mm.

[0202] The macroscopic morphology of the copper-based diamond composite material 100 prepared in Example 3 and the copper-based diamond composite materials prepared in Comparative Examples 1 and 2 was recorded using a mobile phone. The warpage radius of the copper-based diamond composite materials 100 prepared in Examples 3 and 5 and the copper-based diamond composite materials prepared in Comparative Examples 1 and 2 was measured. Surface morphology data of the samples were acquired using a Keyence 3D-profilometer, and the warpage radius was calculated and fitted. Raman spectroscopy of the copper-based diamond composite material 100 prepared in Example 3 and the copper-based diamond composite material prepared in Comparative Example 1 was performed using a Renishaw PLC / inVia microconfocal Raman spectrometer at room temperature and pressure. The heat dissipation temperature of the copper-based diamond composite material 100, alumina, and aluminum nitride prepared in Example 3 was measured at different power levels using a FOTRIC 228s infrared imager. The copper-based diamond film composite material 100 prepared in Example 3 was measured using a ZEISS GeminiSEM. The microstructure of the nanodiamond film on the first surface and the microdiamond film on the second surface were captured by a 300 field emission scanning electron microscope system.

[0203] like Figures 6-8 As shown in the three macroscopic morphology images, it can be observed that the copper-based diamond composite material 100 prepared in Example 3 exhibits excellent thermal stability during cooling. Compared with the copper-based diamond composite material prepared in Comparative Example 1, it did not show cracking defects after cooling. Compared with the copper-based diamond composite material prepared in Comparative Example 2, the copper-based diamond composite material 100 prepared in Example 3 has significantly lower warpage, indicating that the copper-based diamond composite material 100 prepared in Example 3 of this application exhibits low warpage and is not prone to interface cracking. Furthermore, as Figures 15-16 As shown in the two microscopic morphology images, it can be found that neither the nanodiamond film nor the microdiamond film exhibits cracking. In summary, the comprehensive observation and analysis of the macroscopic and microscopic morphology images demonstrates that the copper-based diamond composite material 100 prepared in Example 3 of this application has low warpage and is not prone to interface cracking, fully proving that this composite material has significant advantages in terms of thermal stability and structural reliability.

[0204] like Figures 9-12As shown, the copper-based diamond composite material 100 prepared in Example 3 and 5 both showed significant thermal stability during the cooling process, wherein the warping radius of the copper-based diamond composite material 100 prepared in Example 3 was 395.028 mm, and the warping radius of the copper-based diamond composite material 100 prepared in Example 5 was 534.680 mm, the data showed that the warping radius of the copper-based diamond composite material 100 prepared in Example 5 was larger, and the warping radius of the copper-based diamond composite material prepared in Comparative Example 1 was 58.187 mm, and the warping radius of the copper-based diamond composite material prepared in Comparative Example 2 was 55.530 mm, the warping degree of the copper-based diamond composite material 100 prepared in Example 5 was reduced by 9.19 times compared with the copper-based diamond composite material prepared in Comparative Example 1, and reduced by 9.63 times compared with the copper-based diamond composite material prepared in Comparative Example 2, it can be seen that the larger the warping radius, the higher the material surface flatness, which indicates that the surface flatness of the copper-based diamond composite material 100 prepared in Example 3 and 5 is high.

[0205] As shown in FIG. 1a, Figure 13 The single side is the copper-based diamond composite material prepared in Comparative Example 1, and the double side is the copper-based diamond composite material 100 prepared in Example 3, wherein the Raman peak position of the copper-based diamond composite material 100 prepared in Example 3 is located at 1335.52 cm- 1 , and the Raman peak position of the copper-based diamond composite material prepared in Comparative Example 1 is located at 1337.24 cm- 1 , which is farther away from the stress-free peak position of 1332.5 cm- 1 , indicating that the copper-based diamond composite material prepared in Comparative Example 1 has greater thermal stress inside, which is the main reason for cracking, and the double-sided deposition structure of the copper-based diamond composite material 100 prepared in Example 3 effectively promotes the thermal stress release of the diamond film layer.

[0206] As shown in FIG. 2a, Figure 14 The heating ceramic was respectively attached to the Cu-Diamond (the copper-based diamond composite material 100 prepared in Example 3), the alumina (Al2O3) and the aluminum nitride (AlN) heat dissipation substrate by using the conductive silver paste, and the heat dissipation temperature under different power was measured; as shown in FIG. 2b, Figure 14As shown in b, at 2W power, the heat dissipation temperature of Cu-Dia (copper-based diamond composite material 100 prepared in Example 3) is 21.4℃, that of Al2O3 is 33.6℃, and that of AlN is 22.5℃; at 4.5W power, the heat dissipation temperature of Cu-Dia is 33.3℃, that of Al2O3 is 58.3℃, and that of AlN is 37.2℃; at 6W power, the heat dissipation temperature of Cu-Dia is 53.8℃, that of Al2O3 is 95.6℃, and that of AlN is 61.2℃, from which it can be seen that the heat dissipation temperature of Cu-Dia is always lower than that of Al2O3 and AlN in the power scenarios of 2W, 4.5W and 6W; as shown in Figure 14 As shown in c, the heat dissipation temperature rising rate of Cu-Diamond (copper-based diamond composite material 100 prepared in Example 3) is the lowest, followed by that of AlN, and that of Al2O3 is the highest. In summary, the heat dissipation effect of the copper-based diamond composite material 100 prepared in Example 3 is better than that of alumina and aluminum nitride, indicating that the copper-based diamond composite material 100 prepared in Example 3 of the present application has good heat dissipation performance and can be used in electronic products and semiconductor devices and other products that need to be quickly and efficiently cooled.

[0207] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be considered as disclosed by the present application and belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method of producing a copper-based diamond composite material, characterized by, The method comprises the following steps: A copper substrate is provided, the copper substrate including opposing first and second surfaces, the copper substrate having a thickness of 0.1 mm to 5 mm, the first and second surfaces having an area of 100 mm 2 ~ 2000 mm 2 , the copper substrate having a ratio of the area of the copper substrate to the thickness of the copper substrate of 100:1 to 5000:

1. preparing a stress buffer layer on the first surface of the copper substrate, the first preparation temperature during the preparation being controlled at 150-900 ℃, and the thickness of the stress buffer layer being controlled at 1-80 μm during the preparation, and the thermal expansion coefficient of the stress buffer layer being less than that of the copper substrate; preparing a diamond film layer on the second surface of the copper substrate, the second preparation temperature during the preparation being controlled at 600-900 ℃, and the thickness of the diamond film layer being controlled at 1-30 μm during the preparation.

2. A method of producing a copper-based diamond composite material, characterized by, The method comprises the following steps: providing a copper substrate, the copper substrate comprising opposite first and second surfaces; selecting the type of stress buffer layer on the first surface of the copper substrate and the corresponding preparation process parameters, wherein the preparation process parameters include the thickness of the stress buffer layer and the first preparation temperature; calculating the first stress generated by the stress buffer layer on the copper substrate when the stress buffer layer is reduced from the first preparation temperature to room temperature; preparing a stress buffer layer on the first surface of the copper substrate according to the type of the stress buffer layer and the corresponding preparation process parameters; selecting the type of diamond film layer on the second surface of the copper substrate and the corresponding preparation process parameters, wherein the preparation process parameters include the thickness of the diamond film layer and the second preparation temperature; calculating the second stress generated by the diamond film layer on the copper substrate when the diamond film layer is reduced from the second preparation temperature to room temperature, the second stress being opposite to the first stress, and the difference between the second stress and the first stress being less than or equal to 1.5 GPa; preparing a diamond film layer on the second surface of the copper substrate according to the type of the diamond film layer and the corresponding preparation process parameters.

3. The production method according to claim 1 or 2, characterized by, The thickness of the stress buffer layer is denoted as H1, and the thickness of the diamond film layer is denoted as H2, wherein H1 and H2 satisfy the relationship as shown in formula 1: In the formula, E1, v1, a1, H1, and AT1 are the elastic modulus, Poisson's ratio, thermal expansion coefficient, thickness of the stress buffer layer, and the temperature difference between the first preparation temperature and room temperature, respectively; E2, v2, a2, H2, and AT2 are the elastic modulus, Poisson's ratio, and thermal expansion coefficient of the diamond film layer, thickness, and the temperature difference between the second preparation temperature and room temperature, respectively; a Cu coefficient of thermal expansion of the copper substrate.

4. The production method according to claim 1 or 2, characterized by, The thickness of the copper base material is 0.3 mm to 1 mm, the area of the first surface and the second surface is 300 mm 2 to 800 mm 2 , and the ratio of the area of the copper base material to the thickness of the copper base material is 800: 1 to 2000:

1.

5. The production method according to claim 1 or 2, characterized by, The type of the stress buffer layer is selected from at least one of nanocrystalline diamond film, diamond-like carbon film and hard alloy film, and the type of the diamond film layer includes nanocrystalline diamond film or microcrystalline diamond film.

6. The preparation method according to claim 5, wherein the stress buffer layer comprises nanocrystalline diamond film, the thickness of the nanocrystalline diamond film being 1-30 μm, the nanocrystalline diamond film being prepared by hot filament chemical vapor deposition, and the first preparation temperature being 600-750 ℃; or the stress buffer layer comprises diamond-like carbon film, the thickness of the diamond-like carbon film being 5-60 μm, the diamond-like carbon film being prepared by filtered cathode arc method, and the first preparation temperature being 150-400 ℃; or the stress buffer layer comprises hard alloy film, the thickness of the hard alloy film being 5-80 μm, the hard alloy film being selected from at least one of titanium carbide, tungsten carbide, tantalum carbide, titanium carbonitride and tungsten boride, and the hard alloy film being prepared by magnetron sputtering plating method, and the first preparation temperature being 150-500 ℃.

7. The preparation method according to claim 5, wherein ​ ​ The diamond film layer comprises a nanocrystalline diamond film, the thickness of the nanocrystalline diamond film is 1-30 μm, the nanocrystalline diamond film is prepared by a hot filament chemical vapor deposition method, and the second preparation temperature is 600-750 ℃; or the nanocrystalline diamond film is prepared by a microwave plasma chemical vapor deposition method, and the second preparation temperature is 600-750 ℃. Or, the diamond film layer comprises a microcrystalline diamond film, the thickness of the microcrystalline diamond film is 1-20 μm, the microcrystalline diamond film is prepared by a hot filament chemical vapor deposition method, and the second preparation temperature is 780-900 ℃; or the microcrystalline diamond film is prepared by a microwave plasma chemical vapor deposition method, and the second preparation temperature is 750-850 ℃.

8. The production method according to claim 1 or 2, characterized by, The copper substrate is provided, and the first surface and the second surface of the copper substrate are pretreated, the pretreatment process comprises: Mechanically grinding the first surface and the second surface of the copper substrate to a surface roughness Ra≤10 μm; Grinding the first surface and the second surface of the copper substrate with diamond micro-powder particles with a particle size of 0.1-50 μm, and the grinding time is 5-30 min; Ultrasonic cleaning the copper sheet with deionized water and ethanol respectively, and the cleaning time is 10-100 min, and the surface is dried with N2 or Ar; Treating the first surface and the second surface with an argon plasma etching machine with a power of 200-400 W, and the treatment time is 5-15 min.

9. The production method according to claim 1 or 2, characterized by, After the step of preparing the diamond film layer on the second surface of the copper substrate, the stress buffer layer is removed, and the removal of the stress buffer layer comprises the following steps: Fixing the diamond film layer of the copper-based diamond composite material on a clamp with an adhesive, and placing the clamp on a grinding machine, so that the outer surface of the stress buffer layer serves as a surface to be ground; Setting the grinding time to 30-40 min, the pressure to 0.2-0.4 MPa, and the rotation speed to 180-220 r / min, and removing the stress buffer layer by grinding; After the grinding is completed, the clamp and the copper substrate with the diamond film layer on the second surface are placed on a heating table together, the temperature of the heating table is 280-320 ℃, the adhesive is softened, and then the copper substrate with the diamond film layer on the second surface is separated from the clamp; After the separation, the sample is ultrasonically cleaned with anhydrous ethanol, and the cleaning time is 20-40 min, so as to completely remove the adhesive remaining on the surface of the diamond film layer.

10. The production method according to claim 1 or 2, characterized by, Before the step of preparing the stress buffer layer on the first surface of the copper substrate, a transition layer is plated on the first surface and / or the second surface of the copper substrate by a magnetron sputtering method, the transition layer is at least one of titanium, chromium, tungsten, tantalum, titanium carbide, tungsten carbide, titanium nitride, tungsten nitride and chromium nitride, and the thickness of the transition layer is 50-800 nm.

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