A method for preparing gallium-based liquid metal thermal interface material by plating Ga2O3 on diamond particles

Abstract

The application discloses a method for preparing gallium-based liquid metal thermal interface material by coating Ga2O3 on diamond particles. The method comprises the following steps: firstly, preparing gallium-based liquid metal by heating metal gallium, indium and tin with a specified ratio; secondly, coating Ga2O3 on the surface of specified diamond particles by low-pressure chemical vapor deposition after ultrasonic cleaning, wherein liquid gallium and high-purity oxygen are used as precursors, and high-purity argon is used as a protective gas; thirdly, mixing the prepared gallium-based liquid metal and the diamond particles coated with Ga2O3 and stirring in an oxygen-free environment; and fourthly, preparing high-thermal-conductivity gallium-based liquid metal thermal interface material after the interface wetting of the mixed composite material is regulated by Ga2O3 through ultrasonic-assisted wetting. The method can finely regulate the layer thickness of Ga2O3 between two phases, efficiently utilize Ga2O3 to improve the interface wetting, and reduce the negative effect of low thermal conductivity of Ga2O3 to the minimum, so that the gallium-based liquid metal thermal interface material with high thermal conductivity is finally prepared.

Description

Technical Field

[0001] This invention belongs to the field of metal-based thermal interface materials, specifically relating to a method for preparing gallium-based liquid metal thermal interface materials by coating diamond particles with Ga2O3. Background Technology

[0002] Advanced thermal management processes combine high thermal conductivity packaging materials, thermal interface materials, heat storage materials, and thermoelectric materials with power devices to construct efficient and stable heat dissipation channels. In flip-chip ball grid array (FCBGA) packages, thermal interface materials establish efficient heat dissipation channels between the bare die and the heat sink (cover plate), thereby effectively reducing junction temperature and preventing chip failure. Gallium-based liquid metal thermal interface materials have thermal conductivity far exceeding that of mainstream thermal greases and are expected to gain a larger application market.

[0003] Adding nanodiamond particles to liquid metal can further improve its thermal conductivity and enhance its flowability to suppress spillover. However, the poor wettability between diamond particles and the liquid metal matrix limits the full utilization of its high thermal conductivity. Ga2O3, which is easily generated in liquid metal under oxygen conditions, can significantly improve the interfacial wetting between diamond and liquid metal. However, the disordered distribution of Ga2O3 generated by random oxidation and its very low intrinsic thermal conductivity are detrimental to the overall performance of the composite material. Existing diamond-based gallium-based liquid metal thermal interface materials often employ surface modification with a metal layer to improve two-phase wetting. However, the thermal conductivity of the metal carbide layer is generally low, and it introduces more interfaces. Some studies have also noted the application of Ga2O3 in the assembly process of gallium-based liquid metal thermal interface materials to improve the spreading problem of gallium-based thermal interface materials on specific metal surfaces. However, the preparation process of these diamond-based gallium-based liquid metal thermal interface materials has not fully considered the combined effects of Ga2O3 on interfacial wetting and interfacial thermal conductivity at the two-phase interface. Summary of the Invention

[0004] To address the problems existing in current preparation technologies, this invention provides a method for preparing gallium-based liquid metal thermal interface materials by coating diamond particles with Ga2O3. Ga2O3 is deposited on the surface of diamond particles using a low-pressure vapor phase chemical deposition method, and then fully mixed with gallium-based liquid metal in an oxygen-free environment. This allows for precise control of the Ga2O3 layer thickness between the two phases, efficiently utilizing Ga2O3 to improve interface wetting while minimizing the negative effects of its low thermal conductivity.

[0005] The technical solution of this invention is as follows:

[0006] A method for preparing gallium-based liquid metal thermal interface materials by coating Ga2O3 with diamond particles includes the following steps;

[0007] Step 1: Preparation of gallium-based liquid metal: Place the specified ratio of gallium, indium and tin in a crucible, heat it to the rated temperature through a vacuum furnace, cool it down and take it out after forming liquid metal;

[0008] Step 2: Diamond particle cleaning: Select diamond particles of the specified size and ultrasonically clean them with dilute hydrochloric acid, then rinse them with alcohol.

[0009] Step 3: Ga2O3 plating: The diamond particles cleaned in Step 2 are spread evenly in the reaction crucible. High-purity liquid gallium is used as the precursor. High-purity oxygen and high-purity argon as a protective gas are introduced at the same time. The temperature is raised to the specified temperature and cooled after the reaction is completed. Protective argon is then introduced.

[0010] Step 4: Mixing gallium-based liquid metal and Ga2O3-coated diamond particles: Mix and stir the gallium-based liquid metal and Ga2O3-coated diamond particles obtained in the above steps in an oxygen-free environment.

[0011] Step 5: Preparation of thermal interface material: The mixed composite material is ultrasonically assisted to wet, and a high thermal conductivity gallium-based liquid metal thermal interface material with interface controlled by Ga2O3 is obtained.

[0012] Furthermore, in step 1, the mass percentages of gallium, indium, and tin are 45-60% gallium, 25-40% indium, and 5-10% tin, respectively, and the heating temperature is 300-400°C.

[0013] Furthermore, in step 2, the diamond particles have a particle size of 50–200 μm, and the dilute hydrochloric acid has a mass concentration of 5–25%.

[0014] Furthermore, in step 3, the volume ratio of oxygen to argon is 1-5%, the heating temperature is 700-950℃, and the Ga2O3 film thickness is 0.2-1.5μm.

[0015] Furthermore, in step 4, the volume ratio of diamond particles in the mixture is 20-60%, the diamond particle size is a single particle size or a combination of 2-3 particle sizes, and the stirring time is 10-40 minutes.

[0016] Furthermore, in step 5, the ultrasonic-assisted wetting time is 15 to 40 minutes.

[0017] The beneficial effects of this invention are as follows:

[0018] This invention uses a low-pressure vapor phase chemical deposition method to deposit Ga2O3 on the surface of diamond particles and fully mixes it with gallium-based liquid metal in an oxygen-free environment. This allows for precise control of the Ga2O3 layer thickness between the two phases, efficiently utilizing Ga2O3 to improve interface wetting while minimizing the negative effects of its low thermal conductivity, ultimately producing a gallium-based liquid metal thermal interface material with high thermal conductivity. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the preparation of gallium-based liquid metal thermal interface materials by coating Ga2O3 with diamond particles according to the present invention. Detailed Implementation

[0020] The present invention will be further described below with reference to specific embodiments.

[0021] Example 1: Preparation of Gallium-based Liquid Metal Thermal Interface Material by Coating Diamond Particles with Ga2O3

[0022] Includes the following steps;

[0023] Step 1: Prepare gallium-based liquid metal. Place the specified ratio of gallium, indium, and tin in a crucible, heat it to the rated temperature through a vacuum furnace, and then cool and remove it after forming liquid metal.

[0024] Step 2: Select diamond particles of a specified size and ultrasonically clean them with dilute hydrochloric acid, then rinse them with alcohol.

[0025] Step 3: Coating with Ga2O3. Diamond particles are spread evenly in a reaction crucible. High-purity liquid gallium is used as a precursor. High-purity oxygen and high-purity argon as a protective gas are introduced simultaneously. The temperature is raised to the specified temperature and the reaction is completed. The power is turned off and the temperature is lowered, while protective argon is introduced again.

[0026] Step 4: Mix and stir the gallium-based liquid metal obtained in the previous steps and the diamond particles coated with Ga2O3 in an oxygen-free environment;

[0027] Step 5: The mixed composite material is ultrasonically assisted to wet it, and a high thermal conductivity gallium-based liquid metal thermal interface material with interface controlled by Ga2O3 is obtained.

[0028] In Example 1: the mass fractions of gallium, indium, and tin were 52% gallium, 40% indium, and 8% tin, and the heating temperature during the mixing preparation was 300°C; the diamond particles had two sizes, 100 μm and 200 μm, and the mass concentration of dilute hydrochloric acid was 10%; the volume ratio of oxygen to argon was selected as 2.3% when coating Ga2O3, the heating temperature was selected as 880°C, and the thickness of the Ga2O3 film was 1.1 μm; the volume ratio of diamond particles in the mixture was 50%, the ratio of the two diamond particle sizes was 1:1, the stirring time was 25 minutes, and after stirring, ultrasonic-assisted wetting was performed for 15 minutes.

[0029] The working principle of the present invention will be explained below with reference to the accompanying drawings. Figure 1 As shown:

[0030] (1) To prepare gallium-based liquid metal, gallium, indium and tin in a mass ratio of 52:40:8 were placed in a crucible, heated to 300°C in a vacuum furnace to form liquid metal, then cooled and removed.

[0031] (2) Select 100μm and 200μm diamond particles and ultrasonically clean them with 15% dilute hydrochloric acid, then rinse them with alcohol.

[0032] (3) Diamond particles were spread in a reaction crucible. High-purity liquid gallium was used as a precursor. High-purity oxygen and high-purity argon were introduced at the same time. The volume ratio of oxygen to argon was 2.3%. After the reaction was completed at 880°C, the power was turned off and the temperature was lowered. Protective argon was introduced. After the coating was completed, the diamond particles were removed, sieved and separated and ultrasonically cleaned. The coating thickness and uniformity were characterized by SEM. The thickness of the Ga2O3 coating on the diamond surface was 1.1 μm.

[0033] (4) In an oxygen-free environment, the gallium-based liquid metal obtained in the above steps and the diamond particles coated with Ga2O3 are mixed and stirred. The diamond volume ratio is 50%, the two particle sizes are in a 1:1 ratio, and the mixture is stirred for 25 minutes.

[0034] (5) The mixed composite material was ultrasonically assisted to wet for 15 minutes to obtain a high thermal conductivity gallium-based liquid metal thermal interface material after interface wetting controlled by Ga2O3.

[0035] Obviously, the above embodiments are only some embodiments of the present invention, and not all embodiments. The above embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention. Based on the above embodiments, all other embodiments obtained by those skilled in the art without creative effort, that is, all modifications, equivalent substitutions, and improvements made within the spirit and principle of this application, fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing gallium-based liquid metal thermal interface materials by coating Ga2O3 with diamond particles, comprising the following steps: Step 1: Preparation of gallium-based liquid metal: Place 45-60% gallium, 25-40% indium, and 5-10% tin by mass into a crucible, with the total amount of gallium, indium, and tin equal to 100%. Heat the crucible to the rated temperature in a vacuum furnace to form liquid metal, then cool it down and remove it. Step 2: Diamond particle cleaning: Select diamond particles of a specified size and ultrasonically clean them with dilute hydrochloric acid, then rinse them thoroughly with alcohol; the diamond particle size is 50~200μm, and the mass concentration of dilute hydrochloric acid is 5~25%; Step 3: Ga2O3 coating: The diamond particles cleaned in Step 2 are spread evenly in the reaction crucible. High-purity liquid gallium is used as the precursor. High-purity oxygen and high-purity argon as a protective gas are introduced at the same time. The temperature is raised to the specified temperature and cooled after the reaction is completed. Protective argon is continued to be introduced to make the Ga2O3 film thickness on the surface of the diamond particles 0.2~1.5μm. Step 4: Mixing gallium-based liquid metal and Ga2O3-coated diamond particles: Mix and stir the gallium-based liquid metal and Ga2O3-coated diamond particles obtained in the above steps in an oxygen-free environment. Step 5: Preparation of thermal interface material: The mixed composite material is ultrasonically assisted to wet, and a high thermal conductivity gallium-based liquid metal thermal interface material with interface controlled by Ga2O3 is obtained.

2. The method according to claim 1, wherein in step 1, the rated temperature is 300~400℃.

3. The method according to claim 1, wherein in step 3, the specified temperature is 700~950℃.

4. According to the method of claim 1, in step 4, the volume percentage of diamond particles in the mixed composite material is 20-60%, and the diamond particle size is a single particle size or a combination of 2-3 particle sizes.

5. According to the method of claim 1, in step 4, the stirring time is 10-40 minutes.

6. According to the method of claim 1, in step 5, the ultrasonic-assisted wetting time is 15-40 minutes.

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