High-thermal-conductivity diamond-copper composite material interface regulation and preparation method thereof

Abstract

The invention discloses a high-thermal-conductivity diamond copper composite material interface regulation and control method and a preparation method thereof, and relates to the technical field of new materials. The method at least comprises the following steps that S1, diamond particles are cleaned and dried; and S2, placing the diamond particles treated in the step 1 in a magnetron sputtering device, fixing the diamond particles on a turntable, and then vacuumizing a working cavity to 10 <-2 >-10 <-4 > Pa. According to the method, surface modification of sputtered diamond particles is completed, diamond surface metal carbonization is achieved without heat treatment, diamond graphitization is avoided fundamentally, and the heat conductivity of the diamond-copper composite material is improved; and the surface of the diamond can be uniformly plated and completely wrapped with a single-layer or multi-layer thin film according to needs, so that the effect of subjectively controlling the components of the thin film layer is achieved, and the problem of random carbonization of metal on the surface of the diamond in the heat treatment process is solved.

Description

Technical Field

[0001] The invention relates to the technical field of new materials, and in particular to interface control of a high thermal conductivity diamond-copper composite material and a preparation method thereof. Background Art

[0002] With the trend of miniaturization and integration of electronic devices, the power density of electronic components has increased significantly, resulting in a rapid increase in the heat generated in the equipment. In order to effectively control the temperature of electronic components and ensure their normal operation, the design of the heat dissipation system is crucial. Therefore, materials with high thermal conductivity are urgently needed to meet contemporary thermal needs. The thermal conductivity of traditional electronic packaging substrates (crystalline silicon) is 120-150W / (m·K). Diamond has an extremely high thermal conductivity of 1200~2500W / (m·K), which has attracted much attention due to its excellent thermal properties. However, the manufacturing process of diamond on electronic devices is very difficult and expensive, which makes it difficult to use diamond directly in the electronics industry. Another solution is to combine diamond particles with a copper matrix (the thermal conductivity of copper is 400W / (m·K)).

[0003] However, due to the high surface tension of copper and the large wetting angle between copper and diamond, the wettability between diamond particles and liquid metal is generally poor, and the excellent thermal properties of diamond cannot be fully utilized. Therefore, several methods are used to solve this problem. These methods include adding different active elements (such as Cr or B) to the matrix, and coating the diamond surface with strong carbide deformation elements (such as Ti, Cr, Mo or W), and then forming the corresponding carbides through heat treatment (above 800°C). Related research results show that these elements as an intermediate layer effectively improve the bonding strength and thermal physical properties of the material.

[0004] At present, the preparation technologies of diamond / Cu composite materials mainly include high temperature and high pressure (HTHP), hot pressing (HP), squeeze casting, gas pressure infiltration, spark plasma sintering (SPS), etc. However, the preparation technology of diamond / Cu composite materials mainly requires a higher sintering temperature (950-1827℃), and active elements are generally added to reduce the sintering temperature during the powder metallurgy sintering process. At high temperatures, part of the diamond surface will be transformed into more stable graphite, and the corresponding metal will also be carbonized, and the carbonization of the metal cannot be controlled. This phenomenon leads to a decrease in thermal conductivity.

[0005] In order to solve the problem of graphitization of diamond, which affects the decrease of thermal conductivity, the present invention provides a diamond surface modification method, and the related technology has important application value in the preparation of diamond copper composite materials. Summary of the invention

[0006] The object of the present invention is to provide a high thermal conductivity diamond copper composite material interface control and preparation method thereof, using magnetron sputtering technology and acetylene as a carbon source, W / B / Cr / Ti / Zr / Mo as a target material, directly depositing the required metal and its carbide on the surface of diamond particles, thereby modifying the diamond surface and avoiding heat treatment to prevent diamond graphitization from the source, and subsequently preparing the diamond copper composite material by cold spraying or other methods mentioned above, the thermal conductivity of the diamond copper composite material prepared in this way is 500-950W / mK, and the thermal conductivity coefficient is improved, so as to solve the technical problems raised in the background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a high thermal conductivity diamond copper composite material interface control and preparation method thereof, comprising at least the following steps:

[0008] S1: cleaning and drying of diamond particles;

[0009] S2: The diamond particles processed in step 1 are placed in a magnetron sputtering device, fixed on a turntable, and then the working chamber is evacuated to 10 -2 —10 -4 Pa, reduce impurities and pollution, enhance the sputtering effect to control the film quality, improve the coating efficiency, ensure the stability of the film forming process and the film performance;

[0010] S3: After the working chamber is evacuated, high-purity argon and high-purity acetylene are introduced into the working chamber to keep the pressure in the chamber between 0.133 and 1.33 Pa;

[0011] S4: Adjust the sputtering parameters to ensure that each diamond particle surface can be coated with a film;

[0012] S5: Turn on the power and start pre-sputtering to remove possible contaminants, oxides, impurities or surface unevenness on the target surface, thereby ensuring the quality of the deposited film;

[0013] S6: After the pre-sputtering is completed, the baffle is opened and sputtering is started until the sputtering is completed to obtain the modified diamond;

[0014] S7: chemically plating copper on the modified diamond to obtain a diamond-copper composite material after copper plating and molding.

[0015] Furthermore, the high-purity argon gas in S3 provides an ion source required for sputtering, and the high-purity acetylene provides a carbon source required for sputtering. The acetylene flow rate is related to the cavity size and sputtering power density, and also depends on the required film composition.

[0016] Further, the sputtering parameters of S4 at least include bias voltage, temperature, sputtering power density and turntable rotation speed;

[0017] The bias voltage (note: the bias voltage is generally a negative bias voltage, but for simplicity of description it is generally referred to as bias voltage) is 0V-400V;

[0018] The temperature is room temperature-300°C;

[0019] The sputtering power density is 0.1 W / cm 2 -10 W / cm 2 ;

[0020] The rotating speed of the turntable is 0.5r / min-3.5r / min.

[0021] Furthermore, the pre-sputtering time of S5 is 2 minutes to 5 minutes.

[0022] Furthermore, the copper plating method in S7 at least includes hot pressing or cold spraying. When the hot pressing method requires heating, the temperature must be controlled within 500°C-1300°C during the preparation process, and the insulation time must not exceed 1 hour, otherwise excessive carbonization of diamond will occur during this step.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. The present invention completes the surface modification of diamond particles after sputtering, and does not need to realize metal carbonization on the diamond surface through heat treatment, thus avoiding diamond graphitization from the root and improving the thermal conductivity of the diamond copper composite material;

[0025] 2. The present invention can coat the diamond surface with a uniform, fully wrapped single-layer or multi-layer film as required to achieve the effect of subjectively controlling the composition of the film layer, thereby solving the problem of random carbonization of metal on the diamond surface during heat treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the process of the present invention;

[0028] Figure 2 It is a schematic diagram of the substantial application of the present invention;

[0029] Figure 3 A schematic diagram of a cross section of the diamond of the present invention after heat treatment;

[0030] Figure 4The Raman spectra of diamond particles after annealing and without annealing after acetylene coating of the present invention are shown. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0032] See also Figure 1 , a high thermal conductivity diamond copper composite material interface control and preparation method thereof, comprising at least the following steps:

[0033] S1: cleaning and drying of diamond particles;

[0034] S2: The diamond particles processed in step 1 are placed in a magnetron sputtering device, fixed on a turntable, and then the working chamber is evacuated to 10 -2 —10 -4 Pa, reduce impurities and pollution, enhance the sputtering effect to control the film quality, improve the coating efficiency, ensure the stability of the film forming process and the film performance;

[0035] S3: After the working chamber is evacuated, high-purity argon and high-purity acetylene are introduced into the working chamber to keep the pressure in the chamber between 0.133 and 1.33 Pa;

[0036] S4: Adjust the sputtering parameters to ensure that each diamond particle surface can be coated with a film;

[0037] S5: Turn on the power and start pre-sputtering to remove possible contaminants, oxides, impurities or surface unevenness on the target surface, thereby ensuring the quality of the deposited film;

[0038] S6: After the pre-sputtering is completed, the baffle is opened and sputtering is started until the sputtering is completed to obtain the modified diamond;

[0039] S7: chemically plating copper on the modified diamond to obtain a diamond-copper composite material after copper plating and molding.

[0040] The high-purity argon gas in S3 provides the ion source required for sputtering, and the high-purity acetylene provides the carbon source required for sputtering. The acetylene flow rate is related to the chamber size and sputtering power density, and also depends on the required film composition.

[0041] The sputtering parameters of S4 include at least bias voltage, temperature, sputtering power density and turntable rotation speed;

[0042] Bias voltage (Note: bias voltage is generally negative bias voltage, but for simplicity of description it is generally referred to as bias voltage) is 0V-400V;

[0043] The temperature is room temperature-300℃;

[0044] The sputtering power density is 0.1W / cm 2 -10 W / cm 2 ;

[0045] The turntable rotation speed is 0.5r / min-3.5r / min.

[0046] The pre-sputtering time of S5 is 2 minutes to 5 minutes.

[0047] The copper plating method in S7 at least includes hot pressing or cold spraying. When hot pressing requires heating, the temperature must be controlled within 500°C-1300°C during the preparation process, and the insulation time must not exceed 1 hour, otherwise excessive carbonization of diamond will occur during this step.

[0048] Specifically, a preferred processing solution is further proposed:

[0049] Step 1: Clean and dry the diamond particles

[0050] Step 2: The diamond particles processed in step 1 are placed in a magnetron sputtering device (such as Figure 2 ), and then evacuate the working chamber to 3×10 -3 Pa.

[0051] Step 3: After evacuation in step 2, introduce 100 sccm of high-purity argon and 30 sccm of high-purity acetylene into the chamber, with a working pressure of 0.536 Pa.

[0052] Step 4: Set negative bias voltage: -50 V; temperature: room temperature; sputtering power density: 4.4 W / cm 2 ; Turntable rotation speed: 1r / min.

[0053] Step 5: Turn on the power and start pre-sputtering for 2-5 minutes to remove possible contaminants, oxides, impurities or surface unevenness on the target surface to ensure the quality of the deposited film.

[0054] Step 6: Open the shutter and start sputtering. Time: 1 hour to complete the diamond surface modification (such as Figure 3 right).

[0055] Step 7: Chemical copper plating, hot pressing sintering / cold spray molding

[0056] Based on the method provided by the present invention, refer to Figure 3 , Figure 3 (Left) is a schematic diagram of diamond and its cross-section metal after heat treatment. Figure 3 (Right) is a schematic diagram of diamond and its cross-section metal after direct sputtering of acetylene, with clear contrast;

[0057] Figure 4 (a) 400-4000cm -1 wavelength; Figure 4 (b) 1000-1800cm -1 From the enlarged image, it can be clearly observed that the prepared diamond after acetylene coating has not been graphitized. The unannealed Raman image does not show a W2C peak because W2C has no Raman activity. The annealed Raman image shows a WC peak because W2C is converted into WC.

[0058] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A high thermal conductivity diamond copper composite material interface control and preparation method thereof, characterized in that: At least the following steps are included: S1: cleaning and drying of diamond particles; S2: The diamond particles processed in step 1 are placed in a magnetron sputtering device, fixed on a turntable, and then the working chamber is evacuated to 10 -2 —10 -4 Pa, reduce impurities and pollution, enhance the sputtering effect to control the film quality, improve the coating efficiency, ensure the stability of the film forming process and the film performance; S3: After the working chamber is evacuated, high-purity argon and high-purity acetylene are introduced into the working chamber to keep the pressure in the chamber between 0.133 and 1.33 Pa; S4: Adjust the sputtering parameters to ensure that each diamond particle surface can be coated with a film; S5: Turn on the power and start pre-sputtering to remove possible contaminants, oxides, impurities or surface unevenness on the target surface, thereby ensuring the quality of the deposited film; S6: After the pre-sputtering is completed, the baffle is opened and sputtering is started until the sputtering is completed to obtain the modified diamond; S7: chemically plating copper on the modified diamond to obtain a diamond-copper composite material after copper plating and molding.

2. The method for controlling the interface of a high thermal conductivity diamond-copper composite material and its preparation method according to claim 1, characterized in that: The high-purity argon gas in S3 provides the ion source required for sputtering, and the high-purity acetylene provides the carbon source required for sputtering. The acetylene flow rate is related to the cavity size and sputtering power density, and also depends on the required film composition.

3. The method for controlling the interface of a high thermal conductivity diamond copper composite material and its preparation method according to claim 1, characterized in that: The sputtering parameters of S4 include at least bias voltage, temperature, sputtering power density and turntable rotation speed; The bias voltage is 0V-400V; The temperature is room temperature-300°C; The sputtering power density is 0.1 W / cm 2 -10 W / cm 2 ; The rotating speed of the turntable is 0.5r / min-3.5r / min.

4. The method for controlling the interface of a high thermal conductivity diamond-copper composite material and its preparation method according to claim 1, characterized in that: The pre-sputtering time of S5 is 2 minutes to 5 minutes.

5. The method for controlling the interface of a high thermal conductivity diamond-copper composite material and its preparation method according to claim 1, characterized in that: The copper plating method in S7 at least includes hot pressing or cold spraying. When hot pressing requires heating, the temperature must be controlled within 500° C.-1300° C. during the preparation process, and the insulation time must not exceed 1 hour.

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