Preparation method of molybdenum-copper heat sink material

Abstract

The application discloses a preparation method of a molybdenum-copper heat sink material; the preparation method comprises the following steps: step one, selecting raw materials; step two, arranging a template; step three, wrapping the template; step four, pouring copper slurry; step five, shaping and demolding; and step six, atmosphere sintering; the application has the beneficial effects that the application provides a 1-3 type structure molybdenum-copper composite material, the molybdenum-copper composite material can form a molybdenum-copper interconnection composite according to different volume ratios and mass ratios, 1 is the interconnection dimension of molybdenum, 3 is the interconnection dimension of copper, and finally a molybdenum metal composite material interconnecting copper in a three-dimensional structure is obtained; the problems of the component ratio, the volume ratio and the design deviation of the theoretical value of molybdenum-copper are solved; the molybdenum-copper composite material has high density, consistent performance, better high thermal conductivity, a low thermal expansion coefficient and is matched with a chip; the preparation method has the advantages of simple operation, small process energy consumption, high material utilization, a simple process and low production cost.

Description

Technical Field

[0001] This invention relates to the field of heat sink materials technology, and in particular to a method for preparing a molybdenum-copper heat sink material. Background Technology

[0002] In short, a heat sink is a device or material that can absorb and dissipate heat. Heat sink materials refer to a class of materials that can efficiently transfer heat and dissipate large amounts of thermal energy, and are widely used in the field of heat dissipation. Heat sink materials, with their excellent heat dissipation performance, have successfully achieved a breakthrough in traditional heat dissipation methods. From a molecular structure perspective, heat sink materials are generally composed of materials with high thermal conductivity and large heat capacity. Typical materials include metals such as copper and aluminum, as well as semiconductor materials such as silicon nitride and aluminum nitride. The low resistivity and high thermal conductivity of these materials can effectively conduct heat energy, transferring it away quickly and efficiently. In the field of electronic equipment, heat sink materials are widely used in chip heat dissipation, heat sinks, etc., to ensure the normal operation of electronic equipment. In the nuclear energy field, heat sink materials are used to remove the heat generated by the reactor, ensuring the safe operation of the reactor. Furthermore, heat sink materials also play an indispensable role in industrial heat processing, automobile manufacturing, and other fields. In summary, heat sinks and heat sink materials play important roles in multiple fields. They can effectively manage heat, ensure the stable operation of systems, and are of great significance to modern industrial production and technological development. Among them, metal heat sink materials are commonly used for heat dissipation when integrated circuits are combined with chips. Typical metal heat sink materials are represented by tungsten copper alloy and molybdenum copper alloy. These materials have advantages such as high thermal conductivity, low coefficient of thermal expansion, and compatibility with chips.

[0003] The existing method for preparing molybdenum-copper heat sink materials is the melt infiltration method. This method involves melt infiltration sintering to prepare copper-based composite materials. It requires first molding a molybdenum blank, then degreasing and pre-firing to form a network structure framework with specific pores, followed by capillary infiltration of molten copper into the framework at high temperature to form an alloy-like material. This method has the following drawbacks: 1. The structural strength of the framework often affects the coefficient of thermal expansion of the molybdenum-copper material; 2. The porosity and network structure of the molybdenum framework are difficult to control precisely; 3. The molybdenum-copper composition of the melt-infiltrated molybdenum-copper material deviates from the design value; 4. Problems exist such as unstable density, poor uniformity of coefficient of thermal expansion and thermal conductivity; 5. This preparation process is energy-intensive, has low material utilization, is cumbersome, and has high production costs. Summary of the Invention

[0004] This invention aims to solve the above-mentioned problems and provides a method for preparing a molybdenum-copper heat sink material. It provides a molybdenum-copper composite material with a 1-3 type structure, which can obtain a metal composite material in which molybdenum is connected to copper in a three-dimensional structure; the molybdenum-copper composite material has high density and consistent performance; the preparation method is simple to operate, consumes little energy, has high material utilization, is simple in process, and has low production cost.

[0005] To achieve the above objectives, the present invention provides a method for preparing a molybdenum-copper heat sink material, the steps of which are as follows: S1. Select raw materials: molybdenum rods, copper paste, and prepare templates; S2, Arrangement template: Arrange the molybdenum rods on the template; S3. Wrapping template: Wrap the template with molybdenum rods around to form a cavity with an open top. S4. Casting copper slurry: Cast copper slurry into the mold cavity, level it at room temperature, and degas it under vacuum. S5. Shaping and Demolding: The template and material are cured and shaped at low temperature. After shaping, the material is demolded to obtain the blank of molybdenum-copper composite material with type 1-3 structure. S6. Atmosphere sintering: The blank of the 1-3 type structure molybdenum-copper composite material is sintered in an atmosphere to obtain a molybdenum-copper heat sink material, namely the 1-3 type structure molybdenum-copper composite material. S7. Layered unit segmentation: The sintered 1-3 type structure molybdenum-copper composite material is segmented into layered units to obtain an ultrathin molybdenum-copper heat sink material.

[0006] Furthermore, in step S1, the molybdenum rod is square-column shaped and has a purity of not less than 99.95%; the copper paste has a viscosity of 50-250 Pa·s and a sheet resistance of ≤1.5 MΩ / sq.

[0007] Furthermore, in step S2, the template is made of polytetrafluoroethylene, and the upper layer of the template has a square recessed channel; the molybdenum rod is placed in the square recessed channel perpendicular to the template.

[0008] Furthermore, in step S3, the wrapping material is polytetrafluoroethylene, and its height is equivalent to that of the molybdenum rod.

[0009] Furthermore, in step S4, the leveling temperature is 25°C, the time is 5-20 min, and the vacuum degassing time is 30-120 min.

[0010] Furthermore, in step S5, the low-temperature curing and shaping is achieved by drying in a tunnel oven at a temperature of 150°C for 10-15 minutes.

[0011] Furthermore, in step S6, the atmosphere sintering is carried out in a nitrogen atmosphere sintering furnace with a peak temperature of 950°C and a peak time of 10-20 min.

[0012] Furthermore, after step S6, there is a step S7; step S7 is layered unit segmentation, which involves dividing the sintered 1-3 type structure molybdenum-copper composite material into layered units to obtain an ultrathin molybdenum-copper heat sink material; the layered unit segmentation is wire cutting, and the thickness of a single layer material is 0.1~2mm.

[0013] Furthermore, in steps S1 and S2, the molybdenum rod can also be cylindrical, and the corresponding square sinking channel is a circular sinking channel.

[0014] Furthermore, in step S7, the segmentation of the layered units can also be machined.

[0015] The beneficial effects of this invention are as follows: 1. This invention provides a molybdenum-copper composite material with a 1-3 type structure, which can form a molybdenum-copper interconnected composite according to different volume ratios and mass ratios, where 1 is the interconnection dimension of molybdenum and 3 is the interconnection dimension of copper, finally obtaining a metal composite material in which molybdenum is interconnected with copper in a three-dimensional structure; 2. It solves the problem of design deviation between the composition ratio and volume ratio of molybdenum and copper and the theoretical value; 3. It achieves high density and consistent performance of molybdenum-copper composite materials; 4. It has better high thermal conductivity, low coefficient of thermal expansion, and better chip matching; 5. This preparation method is simple to operate, consumes little energy, has high material utilization, is simple in process, and has low production cost. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the description are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a flowchart of the preparation method of the invention.

[0018] Figure 2 This is a top view of an invention of a molybdenum-copper composite material with a 1-3 structure.

[0019] Figure 3 This is a schematic diagram of a molybdenum-copper composite material with a 1-3 structure.

[0020] The following description, in conjunction with embodiments and the accompanying drawings, further illustrates the realization of the objectives, functional characteristics, and advantages of the present invention. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the invention clearer, the technical solutions of the embodiments of the invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without creative effort are within the scope of protection of the invention.

[0022] Example 1: like Figure 1 , Figure 2, Figure 3 As shown, a molybdenum-copper heat sink material, namely a molybdenum-copper composite material with a type 1-3 structure, is prepared. After cutting, it becomes a single-layer ultrathin Mo50Cu50 material with a type 1-3 structure. The preparation method is as follows: Step 1: Select molybdenum rods and copper paste, and prepare the template. The molybdenum rods are square prisms with a purity of not less than 99.95%. The copper paste has a viscosity of 50-250 Pa·s and a sheet resistance ≤1.5 mΩ / sq. The molybdenum rods have a cross-section of 3*3 mm and a height of 10 mm. Pa·s is the unit of dynamic viscosity in the International System of Units (SI). It describes the magnitude of internal friction during fluid flow and is widely used in engineering, physics, chemistry, and other fields. Ω / sq is surface resistivity, which refers to the resistance per unit area and is often used to measure the conductivity of a material surface. Its unit of measurement is ohms per square. The lower the surface resistivity, the better the conductivity of the material. m is for meters and mm is for millimeters. 3*3 mm represents a square with a side length of 3 millimeters.

[0023] Step 2: Arrange the molybdenum rods on the bottom template, specifically placing the molybdenum rods perpendicular to the template in the square recessed channel.

[0024] Step 3: Wrap the template with the molybdenum rods around it to form a cavity with an opening at the top.

[0025] Step 4: Slowly pour the mixed copper slurry into the template device that holds the molybdenum material, that is, slowly pour the copper slurry from the opening of the cavity; after pouring, allow it to self-level at room temperature for 10 minutes, then vacuum degas; min means minutes.

[0026] Step 5: Place the material after pouring copper slurry, along with the template, into a tunnel furnace for drying. The drying temperature is 150℃ and the time is 15 minutes. At this point, the copper slurry has been cured and shaped. Remove the bottom and surrounding templates to obtain the dried molybdenum-copper blank, which is the blank of the 1-3 type structure molybdenum-copper composite material.

[0027] Step 6: Sinter the blank of the molybdenum-copper composite material with type 1-3 structure in a nitrogen atmosphere at a peak temperature of 950℃ for 10-20 minutes. After natural cooling, a molybdenum-copper heat sink material, namely a molybdenum-copper composite material with type 1-3 structure, is completed.

[0028] Step 7: Cut the molybdenum-copper composite material of type 1-3 into thin slices with a thickness of 0.2 mm to complete the preparation of Mo50Cu50 material with precise volume ratio.

[0029] Table 1 shows the performance parameters of the molybdenum-copper heat sink material prepared in this embodiment, obtained through testing. The mass density was measured using Archimedes' displacement method. The average linear thermal expansion coefficient (hereinafter referred to as thermal expansion coefficient) under the conditions of room temperature to 400℃ was determined according to the standard "QBT 1321-1991 Method for Determination of Average Linear Thermal Expansion Coefficient of Ceramic Materials". The thermal conductivity was measured according to "GB / T 22588-2008 Measurement of Thermal Diffusion Coefficient by Flash Method", and the material density was measured using the displacement method. The corresponding theoretical specific heat capacity was calculated, and finally the thermal conductivity of the material was calculated using the formula.

[0030] Table 2 shows the performance parameters of Mo50Cu50 materials prepared by the melt infiltration process, obtained by testing: By comparing Table 1 and Table 2, the mass density of the molybdenum-copper heat sink material prepared in this embodiment is better than that prepared by the melt infiltration process. The coefficient of thermal expansion of the molybdenum-copper heat sink material prepared in this embodiment is lower than that prepared by the melt infiltration process. The thermal conductivity of the molybdenum-copper heat sink material prepared in this embodiment is better than that prepared by the melt infiltration process.

[0031] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a molybdenum-copper heat sink material, characterized in that, The preparation method involves the following steps: S1. Select raw materials: molybdenum rods and copper paste, and prepare templates; the molybdenum rods are square prisms with a purity of not less than 99.95%; the copper paste has a viscosity of 50-250 Pa·s and a sheet resistance of ≤1.5 mΩ / sq. S2, Arrangement Template: Arrange molybdenum rods on the template; the template is made of polytetrafluoroethylene and has a square recessed channel on the upper layer; the molybdenum rods are placed in the square recessed channel perpendicular to the template. S3. Wrapping template: Wrap the template with molybdenum rods around its perimeter to form a cavity with an open top; the wrapping material is polytetrafluoroethylene, and the height is equal to that of the molybdenum rods. S4. Casting copper slurry: Cast copper slurry into the mold cavity, level it at room temperature, and degas it under vacuum; the leveling temperature is 25℃, the time is 5-20 min, and the vacuum degassing time is 30-120 min. S5. Shaping and Demolding: The template and material are cured and shaped at low temperature. After shaping, the material is demolded to obtain a blank of molybdenum-copper composite material with structure type 1-3. The low-temperature curing and shaping is carried out by drying in a tunnel oven at a temperature of 150°C for 10-15 minutes. The molybdenum-copper composite material with structure type 1-3 is formed by forming molybdenum-copper interconnected composites according to different volume ratios and mass ratios, where 1 represents the interconnection dimension of molybdenum and 3 represents the interconnection dimension of copper. S6. Atmosphere sintering: The blank of the 1-3 type structure molybdenum-copper composite material is sintered in an atmosphere to obtain a molybdenum-copper heat sink material, namely the 1-3 type structure molybdenum-copper composite material; the atmosphere sintering is carried out in a nitrogen atmosphere sintering furnace with a peak temperature of 950℃ and a peak time of 10-20min. S7. Layered unit segmentation: The sintered 1-3 type structure molybdenum-copper composite material is segmented into layered units to obtain an ultrathin molybdenum-copper heat sink material. The layered unit segmentation is wire cutting, and the thickness of a single layer material is 0.1~2mm.

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