Aluminum-based diamond layered composite material and preparation method thereof

Abstract

The invention provides an aluminum-based diamond layered composite material and a preparation method thereof, the aluminum-based diamond layered composite material sequentially comprises an aluminum layer, an aluminum-based diamond layer and an aluminum layer from top to bottom, the surface of diamond powder in the aluminum-based diamond layer is plated with titanium, the thickness of the plating layer is 10-100 nm, and the mass of the titanium-plated diamond powder accounts for 25-55% of the mass of the aluminum-based diamond layer; the thickness of the aluminum layer ranges from 0.5 mm to 1.5 mm, and the thickness of the aluminum-based diamond layer ranges from 1 mm to 4 mm. Titanium is plated on the surface of the diamond powder, so that micro-bulge structures on the surface of the diamond powder can be reduced, the surface roughness is reduced, the interface wettability of the diamond powder is improved, and the surface of the composite material can reach the flatness required by a coating process; titanium is plated on the surface of the diamond powder, so that the aluminum binding force between the aluminum-based diamond layer and the upper and lower layers is improved, and the heat conductivity coefficient and the heat dissipation capability of the composite material are further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic packaging materials, and specifically relates to a high thermal conductivity aluminum-based diamond laminated composite material and a preparation method thereof. Background Art

[0002] The development of existing chip manufacturing processes has encountered bottlenecks, while the demand for chip computing power is increasing day by day, resulting in excessive system heat generation and affecting the stability of the operation of microelectromechanical systems. Chip packaging materials made of single substances, such as ceramics, aluminum, silicon, etc., have a maximum thermal conductivity of no more than 400 W / (m·K), which is difficult to solve the heat dissipation problem of high-power semiconductor devices. At the same time, due to the different thermal expansion coefficients from silicon, the interfacial thermal resistance between semiconductor devices and packaging increases; although copper-based diamond composite materials have high thermal conductivity and thermal expansion coefficients matching silicon, they have a relatively large density and are not suitable for scenarios with high quality requirements.

[0003] As an electronic packaging material with high thermal conductivity, aluminum-based diamond materials have relatively high thermal conductivity (which can reach 600 - 750 W / (m·K)) and low density. However, the particle size of diamond is relatively large (100 - 250 μm), and there will be many micro-protrusions on the material surface, and the micro-protrusion structure will significantly increase the surface roughness, resulting in insufficient film layer bonding strength in the coating process; the bonding strength between metallic aluminum and diamond is weak, thus affecting the thermal conductivity and heat dissipation capacity of the material. Summary of the Invention

[0004] The technical problem to be solved by the present invention is how to improve the film layer bonding strength of aluminum-based diamond materials.

[0005] The present invention realizes the solution to the above technical problem through the following technical means:

[0006] The first aspect of the present invention provides an aluminum-based diamond laminated composite material, which successively includes an aluminum layer, an aluminum-based diamond layer, and an aluminum layer from top to bottom. Titanium is plated on the surface of diamond powder in the aluminum-based diamond layer, the coating thickness is 10 - 100 nm, and the mass of the titanium-plated diamond powder accounts for 25 - 55% in the aluminum-based diamond layer; the thickness of the aluminum layer is 0.5 - 1.5 mm, and the thickness of the aluminum-based diamond layer is 1 - 4 mm.

[0007] Beneficial Effects: By plating titanium on the surface of diamond powder, the present invention can reduce the micro-protrusion structure on the surface of diamond powder, reduce the surface roughness, thereby improving the interfacial wettability of diamond powder, so that the surface of the composite material can reach the flatness required by the coating process; by plating titanium on the surface of diamond powder, the present invention improves the bonding strength between the aluminum-based diamond layer and the upper and lower aluminum layers, and further improves the thermal conductivity and heat dissipation capacity of the composite material.

[0008] The present invention can change the mold according to requirements to obtain an aluminum-based diamond laminated composite material with a specific shape. By adjusting the thickness of each layer and the mass percentage of titanium-plated diamond powder in the aluminum-based diamond layer, an aluminum-based diamond laminated composite material with high thermal conductivity and adjustable coefficient of thermal expansion can be prepared. The high-thermal-conductivity aluminum-based diamond laminated composite material of the present invention has the advantages of high thermal conductivity, adjustable coefficient of thermal expansion, easy processing, and coatability, and can meet the high-thermal-conductivity requirements of electronic packaging materials.

[0009] In the second aspect of the present invention, a preparation method of the above-mentioned aluminum-based diamond laminated composite material is provided, including the following steps:

[0010] S1 Titanium is plated on the surface of diamond powder by vacuum evaporation plating or salt bath method to obtain titanium-plated diamond powder;

[0011] S2 The titanium-plated diamond powder and aluminum powder are mixed and cold-pressed under an inert gas to form an aluminum-based diamond green compact;

[0012] S3 According to the aluminum layers as the upper and lower layers and the middle layer as the aluminum-based diamond green compact, they are loaded into a mold and then pressed to form an aluminum-based diamond laminated green compact;

[0013] S4 The aluminum-based diamond laminated green compact is hot-pressed and sintered under an inert gas to obtain an aluminum-based diamond laminated composite material.

[0014] Beneficial effects: In the present invention, the titanium-plated diamond powder and aluminum powder are pre-pressed into an aluminum-based diamond blank by cold pressing under normal pressure, and then according to the laminated structure, the aluminum-based diamond blank and the aluminum layer are pressed by cold pressing to obtain an aluminum-based diamond-aluminum laminated blank. Finally, the aluminum-based diamond-aluminum laminated blank is hot-pressed and sintered to obtain a dense, high-strength, and uniform microstructural aluminum-based diamond laminated composite material.

[0015] The preparation method of the present invention is easy to implement, has simple processes, and short working hours, realizes the integral sintering densification of the aluminum-based diamond and aluminum layer composite material, and can avoid the formation of a fragile transition layer between the upper and lower layers of aluminum and the aluminum-based diamond material in the middle layer. Titanium is plated on the surface of diamond powder to achieve good metallurgical bonding between layers and improve the comprehensive performance of the aluminum-based diamond laminated composite material.

[0016] Preferably, the diameter of the diamond powder is 120-150 μm; the diameter of the aluminum powder is 30-40 μm, its purity is above 99.95%, and the oxygen content is not more than 0.003%.

[0017] Preferably, the mixing time is 6-8 h.

[0018] Preferably, the pressure of the cold pressing is 80-120 MPa, and the pressure holding time is 25-30 s.

[0019] Preferably, the pressure for pressing is 120 - 170 MPa, and the pressure holding time is 25 - 30 s.

[0020] Preferably, the temperature for hot - pressing sintering is 1000 - 1170 °C, and the sintering pressure is 34 - 45 MPa.

[0021] Preferably, the specific operation of the hot - pressing sintering is to heat up to 900 °C at a rate of 50 - 150 °C / min at room temperature, and then heat up to 1000 - 1170 °C at a rate of 18 - 48 °C / min, and the heat - preservation time is 10 - 15 min.

[0022] Preferably, the inert gas is nitrogen or argon. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a schematic structural view of an aluminum - based diamond laminated composite material in this embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] For the purpose of making the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0025] The test materials and reagents used in the following embodiments, unless otherwise specified, can all be obtained from commercial channels.

[0026] For those technical or conditions not specified in the embodiments, they can all be carried out according to the techniques or conditions described in the literature in this field or according to the product specifications.

[0027] Embodiment 1

[0028] This embodiment provides an aluminum - based diamond laminated composite material and its preparation method, which are as follows:

[0029] The aluminum - based diamond laminated composite material in this embodiment is cylindrical in shape, with a diameter of 45 mm and a thickness of 3.5 mm. The thickness of the aluminum layer is 0.75 mm, the thickness of the aluminum - based diamond material layer is 2 mm, the mass of the titanium - coated diamond powder accounts for 48% of the aluminum - based diamond material layer, the diamond powder is coated with titanium, the coating thickness is 30 nm, the diameter of the diamond powder is 130 μm, and the diameter of the aluminum powder is 30 - 40 μm. The cross - section of the aluminum - based diamond laminated composite material in this embodiment is as Figure 1 shown.

[0030] The preparation method of the high thermal conductivity aluminum-based diamond laminated composite material in this embodiment specifically includes the following steps:

[0031] S1 Titanium plating by vacuum evaporation: Clean diamond powder with a diameter of 130 μm, then place it in the evaporation chamber. Evaporate titanium in a vacuum environment to generate titanium vapor, and finally titanium deposits on the surface of the diamond powder to form titanium-plated diamond powder with a coating thickness of 30 nm.

[0032] S2 Put 94.7 g of titanium-plated diamond powder and 102.6 g of aluminum powder into a stainless steel ball milling tank. The purity of the aluminum powder reaches over 99.95%, and the oxygen content is no more than 0.003%. Argon is introduced into the ball milling tank for protection. Place the ball milling tank in an all-round planetary ball mill and set the ball milling parameters: the self-rotation speed is 500 r / min, the revolution speed is 200 r / min, and the ball milling time is 6 h to form a uniformly mixed powder.

[0033] S3 Load the mixed powder into a stainless steel circular mold, and place the stainless steel circular mold in a servo hydraulic press for cold pressing. Pressing conditions: the pressing pressure is 120 MPa, and the pressure holding time is 20 s to obtain an aluminum-based diamond green compact with a diameter of 45 mm and a thickness of 2 mm.

[0034] S4 Remove the oxide film on the surface of an aluminum material with a thickness of 0.75 mm and a diameter of 45 mm. Place 2 pieces of aluminum material and the aluminum-based diamond green compact in step S3 into a stainless steel circular mold with the aluminum layers as the upper and lower layers and the middle layer as the aluminum-based diamond green compact. Place the stainless steel circular mold in a servo hydraulic press for pressing. Pressing conditions: the pressing pressure is 150 MPa, and the pressure holding time is 20 s to obtain an aluminum-based diamond laminated green compact with a diameter of 45 mm and a thickness of 3.5 mm.

[0035] S5 Load the aluminum-based diamond laminated green compact obtained in step S4 into a graphite mold, and place the graphite mold in a hot press sintering furnace for sintering under high temperature and high pressure conditions. Sintering parameters: the sintering temperature is 1060 °C, and the sintering pressure is 40 MPa; the specific operation is to heat from room temperature to 900 °C at a rate of 100 °C / min, and then heat from 900 °C to 1060 °C at a rate of 30 °C / min. After reaching the sintering temperature, the heat preservation time is 12 min. The inert gas during sintering is argon, and the pressure does not exceed 20 MPa. After sintering is completed, the sintered aluminum-based diamond laminated composite material cools down to room temperature in the graphite mold. After removing the graphite mold, the aluminum-based diamond laminated composite material is obtained.

[0036] The thermal conductivity of the aluminum-based diamond laminated composite material in this embodiment is 315.1 W / (m·K), and the thermal expansion coefficient is 16.2 ppm / K.

[0037] Example 2

[0038] This example provides an aluminum-based diamond laminated composite material and a preparation method thereof. The difference between this example and Example 1 is that the mass of the titanium-plated diamond powder accounts for 35% in the aluminum-based diamond layer, and the preparation method is exactly the same as that of Example 1.

[0039] The high thermal conductivity aluminum-based diamond laminated composite material of this example has a thermal conductivity of 290.9 W / (m·K) and a thermal expansion coefficient of 17.8 ppm / K.

[0040] Example 3

[0041] This example provides an aluminum-based diamond laminated composite material and a preparation method thereof. The difference between this example and Example 1 is that the mass of the titanium-plated diamond powder accounts for 53% in the aluminum-based diamond layer, and the preparation method is exactly the same as that of Example 1.

[0042] The high thermal conductivity aluminum-based diamond laminated composite material of this example has a thermal conductivity of 324.5 W / (m·K) and a thermal expansion coefficient of 15.6 ppm / K.

[0043] Example 4

[0044] This example provides an aluminum-based diamond laminated composite material and a preparation method thereof. The difference between this example and Example 1 is that the thickness of the aluminum layer in the aluminum-based diamond laminated composite material is 0.5 mm, and the thickness of the aluminum-based diamond layer is 3 mm, and the preparation method is exactly the same as that of Example 1.

[0045] The high thermal conductivity aluminum-based diamond laminated composite material of this example has a thermal conductivity of 356.2 W / (m·K) and a thermal expansion coefficient of 14.4 ppm / K.

[0046] Example 5

[0047] This example provides an aluminum-based diamond laminated composite material and a preparation method thereof. The difference between this example and Example 1 is that the thickness of the aluminum material layer in the aluminum-based diamond laminated composite material is 1 mm, and the thickness of the aluminum-based diamond material layer is 2.5 mm, and the preparation method is exactly the same as that of Example 1.

[0048] The aluminum-based diamond laminated composite material of this example has a thermal conductivity of 311.8 W / (m·K) and a thermal expansion coefficient of 16.4 ppm / K.

[0049] Example 6

[0050] This embodiment provides an aluminum-based diamond laminated composite material and a preparation method thereof. The difference between this embodiment and Embodiment 1 is that the shape of the aluminum-based diamond laminated composite material is rectangular parallelepiped, with a length of 45 mm, a width of 3.5 mm, and a height of 3.5 mm. The preparation method is exactly the same as that of Embodiment 1.

[0051] For the aluminum-based diamond laminated composite material of this embodiment, the thermal conductivity is 315.1 W / (m·K), and the thermal expansion coefficient is 16.2 ppm / K.

[0052] Embodiment 7

[0053] This embodiment provides an aluminum-based diamond laminated composite material and a preparation method thereof. The difference between this embodiment and Embodiment 1 is that the surface of the diamond powder is coated with titanium, and the coating thickness is 50 nm. The preparation method is exactly the same as that of Embodiment 1.

[0054] For the aluminum-based diamond laminated composite material of this embodiment, the thermal conductivity is 312.6 W / (m·K), and the thermal expansion coefficient is 16.2 ppm / K.

[0055] Comparative Example 1

[0056] This comparative example provides an aluminum-based diamond laminated composite material and a preparation method thereof. The difference between this comparative example and Embodiment 1 is that the surface of the diamond powder is not coated with titanium. The preparation method is exactly the same as that of Embodiment 1.

[0057] For the aluminum-based diamond laminated composite material of this comparative example, the thermal conductivity is 265.4 W / (m·K), and the thermal expansion coefficient is 19.0 ppm / K. Since titanium is not coated on the surface of the diamond powder in this comparative example, the flatness of the composite material cannot meet the requirements of the coating process, so coating cannot be carried out or the bonding force of the coating layer is poor. The thermal conductivity of the composite material in this comparative example is relatively low, its heat dissipation ability is weak, and the thermal expansion coefficient is relatively high, resulting in poor mechanical properties of the composite material.

[0058] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An aluminum-based diamond laminated composite material, characterized in that, From top to bottom are an aluminum layer, an aluminum-based diamond layer, and an aluminum layer. The diamond powder in the aluminum-based diamond layer is coated with titanium on its surface, and the coating thickness is 10 - 100 nm. The mass of the titanium-coated diamond powder accounts for 25 - 55% of the aluminum-based diamond layer. The thickness of the aluminum layer is 0.5 - 1.5 mm, and the thickness of the aluminum-based diamond layer is 1 - 4 mm.

2. The preparation method of the aluminum-based diamond laminated composite material according to claim 1, characterized in that, It includes the following steps: S1 The surface of the diamond powder is coated with titanium by vacuum evaporation or salt bath method to obtain titanium-coated diamond powder; S2 The titanium-coated diamond powder and aluminum powder are mixed and cold-pressed under inert gas to form an aluminum-based diamond green compact; S3 With the aluminum layers as the upper and lower layers and the middle layer as the aluminum-based diamond green compact, it is loaded into a mold and then pressed to form an aluminum-based diamond laminated green compact; S4 The aluminum-based diamond laminated green compact is hot-pressed and sintered under inert gas to obtain an aluminum-based diamond laminated composite material.

3. The method for preparing the aluminum-based diamond laminated composite material according to claim 2, wherein the diameter of the diamond powder is 120 - 150 μm; the diameter of the aluminum powder is 30 - 40 μm, its purity is above 99.95%, and the oxygen content is not more than 0.003%.

4. The method for preparing an aluminum-based diamond laminated composite material according to claim 2, characterized in that, The mixing time is 6 - 8 h.

5. The method for preparing the aluminum-based diamond laminated composite material according to claim 2, wherein, The pressure of the cold pressing is 80 - 120 MPa, and the pressure holding time is 25 - 30 s.

6. The preparation method of the aluminum-based diamond laminated composite material according to claim 2, characterized in that The pressure of the pressing is 120 - 170 MPa, and the pressure holding time is 25 - 30 s.

7. The preparation method of the aluminum-based diamond laminated composite material according to claim 2, characterized in that, The temperature of the hot-pressing sintering is 1000 - 1170 °C, and the sintering pressure is 34 - 45 MPa.

8. The method for preparing an aluminum-based diamond laminated composite material according to claim 8, wherein, The specific operation of the hot-pressing sintering is to heat up to 900 °C at 50 - 150 °C / min at room temperature, and then heat up to 1000 - 1170 °C at 18 - 48 °C / min, and the heat preservation time is 10 - 15 min.

9. The preparation method of the aluminum-based diamond laminated composite material according to claim 2, characterized in that, The inert gas is nitrogen or argon.

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