Heat dissipation material for high-power chip and preparation method of heat dissipation material

Abstract

The invention relates to the field of powder metallurgy composite material manufacturing, and discloses a heat dissipation material for a high-power chip and a preparation method thereof.The preparation method comprises the following steps that metal evaporation is conducted on diamond micro-powder in vacuum, and diamond powder wrapped by metal objects is obtained; the diamond powder wrapped by the metal object and copper powder are evenly mixed and then subjected to hydrogenation reduction treatment, and a treated mixture is obtained; and the treated mixture is subjected to high-temperature and high-pressure treatment, and the diamond / copper composite material is obtained. By adding the transition layer, the bonding strength of the composite material is effectively enhanced; meanwhile, high temperature and high pressure can reduce the addition amount of copper and greatly improve the heat conductivity coefficient of the diamond / copper composite material.

Description

Technical Field

[0001] The invention relates to the field of powder metallurgy composite material manufacturing, and in particular to a heat dissipation material for high-power chips and a preparation method thereof. Background Art

[0002] With the advancement of technology, chips are getting smaller and smaller, and their integration is getting higher and higher. Heat dissipation is one of the important issues that needs to be solved urgently. The thermal conductivity of diamond reaches more than 2000 W·m -1 ·K -1 , lower expansion coefficient and density, CVD diamond material has high thermal conductivity, but high cost, more cost-effective diamond composite materials have become a solution to chip heat dissipation and have received more and more attention.

[0003] The production conditions of diamond / copper composite materials produced by existing production technology are mainly no pressure or low pressure, and the copper content in diamond / copper composite materials is high, wherein the volume percentage of copper is between 35% and 50%; when the copper content is lower than 35% (volume percentage), the bonding strength of diamond / copper composite materials is low and difficult to form, which greatly limits the thermal conductivity of diamond / copper composite materials. In addition, due to the poor wettability of diamond and copper, the two cannot directly form an effective bond, and the bonding strength is low. At the same time, the thermal conductivity of copper is much lower than that of diamond. Excessive increase in copper content will greatly reduce the thermal conductivity of the composite material.

[0004] Therefore, there is an urgent need for a heat dissipation material for high-power chips and a preparation method thereof to solve the above technical problems. Summary of the invention

[0005] The object of the present invention is to provide a heat dissipation material for high-power chips and a preparation method thereof in view of the deficiencies in the prior art.

[0006] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0007] A method for preparing a heat dissipation material for a high-power chip comprises the following steps:

[0008] S1, vacuum evaporating metal on diamond powder to obtain diamond powder wrapped by metal;

[0009] S2, uniformly mixing the diamond powder wrapped by the metal object with the copper powder and performing a hydrogenation reduction treatment to obtain a treated mixture;

[0010] S3, subjecting the treated mixture to high temperature and high pressure treatment to obtain a diamond / copper composite material.

[0011] Preferably, in step S1, the diamond powder includes coarse-grained diamond powder, medium-fine-grained diamond powder, fine-grained diamond powder and ultrafine-grained diamond powder; the volume ratio of coarse-grained diamond powder, medium-fine-grained diamond powder, fine-grained diamond powder and ultrafine-grained diamond powder is (65-75): (20-15): (10-5): 5.

[0012] Preferably, in step S1, the size range of coarse-grained diamond powder is 100-150 μm, the size range of medium-fine-grained diamond powder is 50-75 μm, the size range of fine-grained diamond powder is 25-40 μm, and the size range of ultrafine-grained diamond powder is 10-20 μm.

[0013] In the present invention, the particle size and gradation of diamond are specially designed to achieve the densest packing, which is beneficial to minimize the heat transfer distance between diamond particles and improve the thermal conductivity.

[0014] Preferably, in step S1, the process of vacuum evaporation of metal is: firstly, the metal element and diamond powder are uniformly mixed, and then the vacuum degree is 10 -3 The vacuum evaporation is carried out under the conditions of Pa, temperature of 1000-1500°C and holding time of 0-60min; after the vacuum evaporation is completed, the diamond powder wrapped by the metal object is sieved.

[0015] Preferably, in step S1, the metal element is at least one of metal cobalt, metal tungsten and metal titanium; and the volume ratio of diamond powder to metal element is (90-97):(3-10).

[0016] In the present invention, the metal involved in the evaporation has high thermal conductivity and good wettability with diamond; it can react with diamond at high temperature to produce compounds to form chemical bonds, and the compounds also have good wettability with copper to form a solid solution; the strength of the diamond / copper composite material is improved through the compound transition layer.

[0017] Preferably, in step S2, the volume ratio of the diamond powder wrapped by the metal object to the copper powder is (60-95):(40-5), and the particle size of the copper powder is 10-40 μm.

[0018] Copper has high thermal conductivity and low price, making it the first choice for heat dissipation composite materials.

[0019] Preferably, in step S2, mixing is performed using a mixer; mixing balls are used during the mixing process, the ball-to-material ratio is (1.5-3):1, the mixing speed is 100-300 r / min, and the mixing time is 5-180 min.

[0020] Specifically, the mixer is an all-round mixer, the mixing tank is a hard alloy tank, and the mixing ball is (5mm diameter) carbide ball.

[0021] The present invention adopts an all-round mixing method to obtain a uniform mixture. The organizational structure of the product determines the performance of the product, and uniform organizational structure and performance can be obtained by uniform mixing.

[0022] Preferably, in step S2, the hydrogenation reduction process is: purifying the mixture of diamond powder and copper powder wrapped in metal objects under the conditions of hydrogen flow rate of 0.01 to 3 L / min, temperature of 500 to 900° C., and insulation time of 10 to 120 min.

[0023] After hydrogen reduction, the oxygen in diamond and copper itself can be removed, and the oxygen in the carbide doped during the mixing process can also be removed, so that the mixture has higher activity and cleanliness, which is beneficial to improve the bonding strength and density, thereby improving thermal conductivity.

[0024] Preferably, in step S3, the high temperature and high pressure process is: synthesizing the diamond / copper composite material under the conditions of a temperature of 1000-1300° C., a pressure of 3.5-5.5 GPa, and a holding time of 1-15 min.

[0025] High pressure can produce a denser organizational structure and improve the thermal conductivity of the material. At the same time, the use of high pressure can use less copper while ensuring density, which is beneficial to improving the thermal conductivity of the material.

[0026] A heat dissipation material for high-power chips is prepared by the above preparation method.

[0027] The present invention discloses a method for preparing a heat dissipation material for a high-power chip. In a vacuum state, one or more layers of metals, such as metal cobalt, metal tungsten, metal titanium, etc., are vacuum-deposited on the surface of diamond; diamond micropowder wrapped with the metal is uniformly mixed with copper powder, and then subjected to hydrogenation reduction treatment; the treated mixture is synthesized under high temperature and high pressure to prepare a diamond / copper composite material; the copper content in the diamond / copper composite material prepared by the present invention is as low as 5%. The present invention significantly reduces the copper content, obtains a high-density and high-strength diamond / copper composite material, and greatly improves the thermal conductivity of the diamond / copper composite material.

[0028] Beneficial effects:

[0029] The present invention effectively enhances the bonding strength of the composite material by adding a transition layer (metal material vapor-deposited on diamond micropowder); at the same time, high temperature and high pressure can reduce the amount of copper added and greatly improve the thermal conductivity of the diamond / copper composite material. DETAILED DESCRIPTION

[0030] The present invention is further described below with reference to specific embodiments. The illustrative embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0031] All raw materials of the present invention have no particular limitation on their sources, and can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0032] There is no particular limitation on the purity of all raw materials in the present invention, and the present invention preferably adopts the conventional purity used in the art.

[0033] The devices used in the present invention are not particularly limited and can be any of the commonly used devices in the art.

[0034] Example 1

[0035] A preparation method of a heat dissipation material for high-power chips:

[0036] The size of coarse diamond powder is 100μm, the size of medium fine powder is 50μm, the size of fine diamond powder is 25μm, and the size of ultrafine powder is 10μm. The volume ratio is 65:20:10:5. In the vacuum evaporation of metal tungsten (mix the metal element tungsten with a particle size of 200μm and diamond evenly, and place it in a vacuum of 10 -3 Pa, temperature 1000°C, heat preservation 60min), wherein the volume ratio of diamond powder to tungsten is 90:10, and after sieving, diamond powder wrapped with metal tungsten is obtained;

[0037] The volume ratio of the diamond powder wrapped by metal tungsten to the copper powder with a particle size of 10μm is 90:10. The diamond powder wrapped by metal tungsten and the copper powder are mixed evenly by a full-range mixer to obtain a mixture. The mixing parameters are: the material tank is a cemented carbide tank, the mixing ball is Carbide ball; ball-to-material ratio is 3:1, speed is 300r / min, time is 60min;

[0038] The mixture was subjected to hydrogenation reduction treatment and then synthesized under high temperature and high pressure to prepare a diamond / copper composite material; the hydrogenation reduction treatment parameters were: hydrogen flow rate 0.05L / min, temperature 800°C, and insulation time 60min; the high temperature and high pressure synthesis parameters were: synthesis temperature 1100°C, pressure 4GPa, and insulation time 10min.

[0039] The thermal conductivity of the diamond / copper composite material obtained in this example is 900 W / (m·k).

[0040] Example 2

[0041] A preparation method of a heat dissipation material for high-power chips:

[0042] The size of coarse-grained diamond powder is 150μm, the size of medium-fine-grained powder is 70μm, the size of fine-grained diamond powder is 30μm, and the size of ultrafine powder is 15μm, and the volume ratio is 75:15:5:5; in the vacuum evaporation of metal tungsten and metal element titanium (mix metal element tungsten with a particle size of 300μm, metal element titanium with a particle size of 300μm, and diamond evenly, and place them under vacuum at 10 -3 Pa, temperature 1200 ° C, heat preservation 30min), wherein the ratio of the volume of diamond micropowder to the volume sum of metal element tungsten and metal element titanium is 97:3, wherein the weight ratio of metal element titanium to metal element tungsten is 1:3, and after sieving, diamond powder wrapped with metal tungsten and metal titanium is obtained;

[0043] The volume ratio of the diamond powder wrapped by metal tungsten and metal titanium to the copper powder with a particle size of 40μm is 95:5. The diamond powder wrapped by metal tungsten and metal titanium and the copper powder with a particle size of 40μm are mixed evenly by a full-range mixer to obtain a mixture; the mixing parameters are: the material tank is a cemented carbide tank, the mixing ball is Carbide ball; ball-to-material ratio is 2:1, speed is 200r / min, time is 30min;

[0044] The mixture was subjected to hydrogenation reduction treatment and then synthesized under high temperature and high pressure to prepare a diamond / copper composite material; the hydrogenation reduction treatment parameters were: hydrogen flow rate 0.1 L / min, temperature 750°C, and insulation time 100 min; the high temperature and high pressure synthesis parameters were: synthesis temperature 1150°C, pressure 5 GPa, and insulation time 15 min.

[0045] The thermal conductivity of the diamond / copper composite material obtained in this example is 950 W / (m·k).

[0046] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A method for preparing a heat dissipation material for a high-power chip, characterized in that: The following steps are involved: S1, vacuum evaporating metal on diamond powder to obtain diamond powder wrapped by metal; S2, uniformly mixing the diamond powder wrapped by the metal object with the copper powder and performing a hydrogenation reduction treatment to obtain a treated mixture; S3, subjecting the treated mixture to high temperature and high pressure treatment to obtain a diamond / copper composite material.

2. The method for preparing a heat dissipation material for a high-power chip according to claim 1, characterized in that: In the step S1, the diamond powder includes coarse-grained diamond powder, medium-fine-grained diamond powder, fine-grained diamond powder, and ultrafine-grained diamond powder; the volume ratio of the coarse-grained diamond powder, medium-fine-grained diamond powder, fine-grained diamond powder, and ultrafine-grained diamond powder is (65-75): (20-15): (10-5):

5.

3. The method for preparing a heat dissipation material for a high-power chip according to claim 2, characterized in that: In the step S1, the size range of the coarse-grained diamond powder is 100-150 μm, the size range of the medium-fine-grained diamond powder is 50-75 μm, the size range of the fine-grained diamond powder is 25-40 μm, and the size range of the ultrafine-grained diamond powder is 10-20 μm.

4. The method for preparing a heat dissipation material for a high-power chip according to claim 1, characterized in that: In step S1, the process of vacuum evaporation of metal is as follows: firstly, the metal element and diamond powder are evenly mixed, and then the vacuum degree is 10 -3 The vacuum evaporation is carried out under the conditions of Pa, temperature of 1000-1500°C and holding time of 0-60min; after the vacuum evaporation is completed, the diamond powder wrapped by the metal object is sieved.

5. A heat dissipation material for high-power chips and a preparation method thereof as claimed in claim 4, characterized in that: In the step S1, the metal element is at least one of metal cobalt, metal tungsten and metal titanium; the volume ratio of diamond powder to metal element is (90-97):(3-10).

6. The method for preparing a heat dissipation material for a high-power chip according to claim 1, characterized in that: In the step S2, the volume ratio of the diamond powder wrapped by the metal object to the copper powder is (60-95): (40-5), and the particle size of the copper powder is 10-40 μm.

7. The method for preparing a heat dissipation material for a high-power chip according to claim 1, characterized in that: In the step S2, mixing is performed by a mixer; mixing balls are used in the mixing process, the ball-to-material ratio is (1.5-3):1, the mixing speed is 100-300 r / min, and the mixing time is 5-180 min.

8. The method for preparing a heat dissipation material for a high-power chip according to claim 1, characterized in that: In step S2, the hydrogenation reduction process is: purifying the mixture of diamond powder and copper powder wrapped by metal objects under the conditions of hydrogen flow rate of 0.01-3 L / min, temperature of 500-900° C., and insulation time of 10-120 min.

9. The method for preparing a heat dissipation material for a high-power chip according to claim 1, characterized in that: In step S3, the high temperature and high pressure process is: synthesizing the diamond / copper composite material under the conditions of a temperature of 1000-1300° C., a pressure of 3.5-5.5 GPa, and a holding time of 1-15 minutes.

10. A heat dissipation material for high-power chips, characterized in that: Prepared by the preparation method according to any one of claims 1 to 9.