Heat dissipation substrate and method for manufacturing the same

Abstract

The application provides a heat dissipation substrate and a preparation method thereof, relates to the technical field of heat dissipation substrate manufacturing, and discloses the heat dissipation substrate, which comprises a copper substrate and a heat dissipation structure; the copper substrate is used for connecting a power module; the heat dissipation structure is arranged on the copper substrate; the heat dissipation structure comprises a heat dissipation aluminum plate and a plurality of heat dissipation columns; the heat dissipation aluminum plate is connected with the surface of the copper substrate; and the heat dissipation columns are arranged on the surface of the heat dissipation aluminum plate away from the copper substrate. The heat dissipation substrate provided by the application can guarantee the bonding strength between the copper substrate and the heat dissipation aluminum plate, the overall heat exchange efficiency and long-term stability, reduce the use amount of copper material in the mode of'saving copper by using aluminum', and successfully solve the problem of balancing the cost and performance of the IGBT heat dissipation plate.

Description

Technical Field

[0001] This application relates to the field of heat dissipation substrate manufacturing technology, and in particular to a heat dissipation substrate and its preparation method. Background Technology

[0002] Currently, heat sinks play a crucial role in high-power IGBT modules. They are not only the core heat dissipation structure and channel, but also directly affect the thermal performance, reliability, and lifespan of the IGBT module. IGBTs generate a large amount of heat during operation, and the heat sink uses highly thermally conductive materials to transfer this heat from the chip to the external environment. Some heat sinks also serve as mechanical supports, fixing the IGBT module in place.

[0003] In the prior art, the heat dissipation substrate consists of three parts: a copper plate, an aluminum plate, and a transition layer plate. The copper plate is in contact with the surface of the power module, the aluminum plate is in contact with the external environment, and the two sides of the transition layer plate are coated with adhesive to bond to the copper plate and the aluminum plate respectively, so that the heat of the power module can be dissipated to the external environment in sequence through the copper plate, the transition layer plate, and the aluminum plate.

[0004] However, after long-term use, the aforementioned heat dissipation substrate is prone to separation at the interface between the transition layer and the copper and aluminum plates, affecting the heat dissipation effect of the heat dissipation substrate. Summary of the Invention

[0005] In view of this, this application provides a heat dissipation substrate and its preparation method, which reduces manufacturing costs while ensuring bonding strength, heat dissipation efficiency and long-term stability.

[0006] To achieve the above objectives, this application provides a heat dissipation substrate and its fabrication method, employing the following technical solution:

[0007] On one hand, embodiments of this application provide a heat dissipation substrate, including a copper substrate and a heat dissipation structure;

[0008] The copper substrate is used to connect the power module;

[0009] The heat dissipation structure is disposed on the copper substrate;

[0010] The heat dissipation structure includes a heat dissipation aluminum plate and a plurality of heat dissipation columns; the heat dissipation aluminum plate is connected to the surface of the copper substrate, and the heat dissipation columns are disposed on the surface of the heat dissipation aluminum plate away from the copper substrate.

[0011] In one possible implementation, the minimum thickness of the heat dissipation aluminum plate is greater than or equal to 0.05 mm and less than or equal to 3 mm.

[0012] In one possible implementation, the plurality of heat dissipation columns are arranged in multiple rows and columns, and the distance between two adjacent heat dissipation columns is greater than or equal to 1.2 mm and less than or equal to 1.5 mm.

[0013] In one possible implementation, the heat dissipation column is configured as a cylindrical heat dissipation column;

[0014] The diameter of the cylindrical heat sink is greater than or equal to 1.5 mm and less than or equal to 2 mm; and / or, the height of the cylindrical heat sink is greater than or equal to 3.5 mm and less than or equal to 4.5 mm.

[0015] In one possible implementation, a metal compound layer is formed between the heat dissipation aluminum plate and the copper substrate;

[0016] The thickness of the metal compound layer is less than or equal to 1 micrometer, the peel strength of the metal compound layer is greater than or equal to 110 Newtons / mm, and the shear strength of the metal compound layer is greater than or equal to 60 MPa.

[0017] On the other hand, embodiments of this application also provide a method for preparing a heat dissipation substrate, comprising:

[0018] Provide copper substrate;

[0019] A heat dissipation structure foundation is formed on the surface of the copper substrate by a casting and rolling process, and the copper substrate and the heat dissipation structure foundation together form a heat dissipation substrate foundation.

[0020] The foundation of the heat dissipation structure is processed to form a heat dissipation structure;

[0021] The heat dissipation structure includes a heat dissipation aluminum plate and a plurality of heat dissipation columns. The heat dissipation aluminum plate is connected to the surface of the copper substrate, and the heat dissipation columns are disposed on the surface of the heat dissipation aluminum plate away from the copper substrate.

[0022] In one possible implementation, the formation of the heat dissipation structure foundation on the surface of the copper substrate via a casting and rolling process includes:

[0023] An aluminum layer is cast onto the surface of the copper substrate;

[0024] The aluminum layer is rolled to form the basis of the heat dissipation structure.

[0025] During the process of casting the aluminum layer on the surface of the copper substrate, the casting speed is greater than or equal to 0.1 m / s and less than or equal to 0.3 m / s; the casting temperature is greater than or equal to 680 degrees Celsius and less than or equal to 700 degrees Celsius; and the casting time is greater than or equal to 0.1 seconds and less than or equal to 0.3 seconds.

[0026] In one possible implementation, rolling the aluminum layer to form the base of the heat dissipation structure includes:

[0027] The copper substrate is rolled on the surface away from the base of the heat dissipation structure by a first roll;

[0028] The surface of the heat dissipation structure base away from the copper substrate is rolled by a second roll, and the surface roughness of the first roll is less than that of the second roll.

[0029] During the rolling process of the aluminum layer, the rolling temperature is greater than or equal to 160 degrees Celsius and less than or equal to 200 degrees Celsius; the rolling pressure is greater than or equal to 240 kN and less than or equal to 300 kN; and the rolling speed is greater than or equal to 3 m / min and less than or equal to 5 m / min.

[0030] In one possible implementation, processing the heat dissipation structure foundation to form a heat dissipation structure includes:

[0031] The heat dissipation structure foundation is cold-forged, and part of the heat dissipation structure foundation forms the heat dissipation aluminum plate foundation, while the remaining part of the heat dissipation structure foundation forms multiple heat dissipation column foundations;

[0032] The heat dissipation column foundation is cut and processed;

[0033] The heat dissipation structure is based on the heat treatment;

[0034] The surface of the heat dissipation substrate base is treated to form the heat dissipation substrate;

[0035] The surface roughness of the heat dissipation substrate is greater than or equal to 0.6 and less than or equal to 1.2.

[0036] This application provides a heat dissipation substrate and its preparation method, comprising a copper substrate and a heat dissipation structure. The heat dissipation structure includes a heat dissipation aluminum plate and multiple heat dissipation pillars. Replacing part of the copper substrate with the heat dissipation aluminum plate helps control the manufacturing cost of the heat dissipation substrate, while the multiple heat dissipation pillars can expand the contact area between the heat dissipation substrate and the external environment, thereby improving the heat dissipation efficiency of the heat dissipation substrate. When using the above-mentioned heat dissipation substrate, the copper substrate is used to connect the power module. The heat from the power module is conducted through the copper substrate to the heat dissipation aluminum plate and the heat dissipation pillars provided on the surface of the heat dissipation aluminum plate. Since the heat dissipation aluminum plate and the heat dissipation pillars are exposed to the external environment, they can dissipate the heat to the external environment.

[0037] Meanwhile, the heat dissipation structure is formed on the copper substrate through a casting and rolling process. When the copper substrate and the heat dissipation aluminum plate are combined, mutual diffusion will occur at the contact surface between the two. Compared with the existing technology, which uses adhesive to bond the copper substrate and the heat dissipation aluminum plate separately by applying adhesive to both sides of the transition layer plate, this process can improve the bonding strength between the copper substrate and the heat dissipation aluminum plate and extend the service life of the heat dissipation substrate. Attached Figure Description

[0038] The specific implementation of the embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific implementation described herein is only for illustration and explanation of the embodiments of this application, and the embodiments of this application are not limited to the specific implementation described below.

[0039] Figure 1 This is a schematic diagram of the structure of one embodiment of the heat dissipation substrate provided in this application.

[0040] Figure 2 for Figure 1 Enlarged structural diagram at point A;

[0041] Figure 3 A schematic diagram of another embodiment of the heat dissipation substrate provided in this application;

[0042] Figure 4 for Figure 3 Enlarged structural diagram at point B;

[0043] Figure 5 A schematic flowchart of one embodiment of the method for preparing a heat dissipation substrate provided in this application;

[0044] Figure 6 This is a schematic flowchart of another embodiment of the method for preparing a heat dissipation substrate provided in this application.

[0045] Explanation of reference numerals in the attached figures:

[0046] 100-Copper substrate;

[0047] 200- Heat dissipation structure;

[0048] 210-Aluminum heat dissipation plate;

[0049] 220-Heat dissipation column;

[0050] 300-Metal compound layer.

[0051] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the embodiments of this application in any way, but rather to illustrate the concepts of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application and how the technical solutions of the embodiments of this application solve the above-mentioned technical problems will be clearly and completely described below with reference to specific embodiments and the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0053] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an indirect connection through an intermediate medium, or the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application according to the specific circumstances.

[0054] In the description of the embodiments of this application, it should be understood that the terms "upper", "lower", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0055] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.

[0056] In this application, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a specific manner.

[0057] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0058] A heat sink is a component used in electronic devices to dissipate heat from the power modules of the electronic device.

[0059] In the prior art, the heat dissipation substrate consists of three parts: a copper plate, an aluminum plate, and a transition layer plate. The copper plate is in contact with the surface of the power module, the aluminum plate is in contact with the external environment, and the two sides of the transition layer plate are coated with adhesive to bond to the copper plate and the aluminum plate respectively, so that the heat of the power module can be dissipated to the external environment in sequence through the copper plate, the transition layer plate, and the aluminum plate.

[0060] However, after long-term use, the aforementioned heat dissipation substrate is prone to separation at the interface between the transition layer and the copper and aluminum plates, affecting the heat dissipation effect of the heat dissipation substrate.

[0061] Based on this, the present application provides a heat dissipation substrate and its preparation method, including a copper substrate and a heat dissipation structure. The heat dissipation structure includes a heat dissipation aluminum plate and multiple heat dissipation pillars. Replacing part of the copper substrate with a heat dissipation aluminum plate helps control the manufacturing cost of the heat dissipation substrate, while multiple heat dissipation pillars can expand the contact area between the heat dissipation substrate and the external environment, thereby improving the heat dissipation efficiency of the heat dissipation substrate. When using the above-mentioned heat dissipation substrate, the copper substrate is used to connect the power module. The heat of the power module is conducted through the copper substrate to the heat dissipation aluminum plate and the heat dissipation pillars provided on the surface of the heat dissipation aluminum plate. Since the heat dissipation aluminum plate and the heat dissipation pillars are exposed to the external environment, they can dissipate the heat to the external environment.

[0062] Meanwhile, the heat dissipation structure is formed on the copper substrate through a casting and rolling process. When the copper substrate and the heat dissipation aluminum plate are combined, mutual diffusion will occur at the contact surface between the two. Compared with the existing technology, which uses adhesive to bond the copper substrate and the heat dissipation aluminum plate separately by applying adhesive to both sides of the transition layer plate, this process can improve the bonding strength between the copper substrate and the heat dissipation aluminum plate and extend the service life of the heat dissipation substrate.

[0063] The technical solutions of the embodiments of this application will be described in detail below with reference to the accompanying drawings and specific examples. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0064] Reference Figure 1 and Figure 4As shown, a first aspect of this application provides a heat dissipation substrate, which includes a copper substrate 100 and a heat dissipation structure 200; the copper substrate 100 is used to connect a power module.

[0065] In a specific implementation, the substrate is used to connect the power module, and the substrate is made of a material with good thermal conductivity, such as copper, aluminum, graphite, etc.; in the above embodiment, the substrate is made of copper to improve the heat dissipation efficiency of the heat dissipation substrate.

[0066] The heat dissipation structure 200 is disposed on the copper substrate 100; the heat dissipation structure 200 includes a heat dissipation aluminum plate 210 and a plurality of heat dissipation pillars 220; the heat dissipation aluminum plate 210 is connected to the surface of the copper substrate 100, and the heat dissipation pillars 220 are disposed on the surface of the heat dissipation aluminum plate 210 away from the copper substrate 100.

[0067] This application provides a heat dissipation substrate, including a copper substrate 100 and a heat dissipation structure 200. The heat dissipation structure 200 includes a heat dissipation aluminum plate 210 and multiple heat dissipation pillars 220. Replacing part of the copper substrate 100 with the heat dissipation aluminum plate 210 helps control the manufacturing cost of the heat dissipation substrate. The multiple heat dissipation pillars 220 can increase the contact area between the heat dissipation substrate and the external environment, thereby improving the heat dissipation efficiency of the heat dissipation substrate. When using the above-mentioned heat dissipation substrate, the copper substrate 100 is used to connect the power module. The heat from the power module is conducted through the copper substrate 100 to the heat dissipation aluminum plate 210 and the heat dissipation pillars 220 provided on the surface of the heat dissipation aluminum plate 210. Since the heat dissipation aluminum plate 210 and the heat dissipation pillars 220 are exposed to the external environment, they can dissipate heat to the external environment.

[0068] Meanwhile, the heat dissipation structure 200 is formed on the copper substrate 100 by casting and rolling process. When the copper substrate 100 and the heat dissipation aluminum plate 210 are combined, mutual diffusion will occur at the contact surface between the two. Compared with the existing technology, which uses adhesive to bond the copper substrate 100 and the heat dissipation aluminum plate 210 on both sides of the transition plate, this process can improve the bonding strength between the copper substrate 100 and the heat dissipation aluminum plate 210 and extend the service life of the heat dissipation substrate.

[0069] Reference Figure 1 As shown, in some embodiments, the minimum thickness of the heat dissipation aluminum plate 210 is greater than or equal to 0.05 mm and less than or equal to 3 mm.

[0070] For example, the minimum thickness can be 0.05 mm, 0.1 mm, 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm, 0.4 mm, 0.6 mm, 0.7 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm, and any range between two values.

[0071] This embodiment, by reasonably setting the minimum thickness of the heat dissipation aluminum plate 210, can meet the actual heat dissipation requirements of the power module while using lower-cost aluminum materials to replace higher-cost copper materials as much as possible, thereby reducing the manufacturing cost of the heat dissipation substrate.

[0072] Meanwhile, the thickness of the heat dissipation aluminum plate 210 has reached the millimeter level, while other common processes such as electroplating are suitable for the preparation of micron-level heat dissipation aluminum plates 210. Therefore, the above-mentioned heat dissipation aluminum plate 210 is prepared by casting and rolling process; and the thickness of the heat dissipation aluminum plate 210 is specifically adjusted by changing the rolling temperature, rolling pressure and rolling speed.

[0073] Reference Figures 1 to 4 As shown, in some embodiments, multiple heat dissipation columns 220 are arranged in multiple rows and columns, and the distance between two adjacent heat dissipation columns 220 is greater than or equal to 1.2 mm and less than or equal to 1.5 mm.

[0074] The heat sink 220 is configured as a cylindrical heat sink; the diameter of the cylindrical heat sink is greater than or equal to 1.5 mm and less than or equal to 2 mm; and / or, the height of the cylindrical heat sink is greater than or equal to 3.5 mm and less than or equal to 4.5 mm.

[0075] Preferably, the diameter of the cylindrical heat sink is 1.7 mm, and the height of the cylindrical heat sink is 3.9 mm. Exemplarily, the spacing can be 1.2 mm, 1.25 mm, 1.3 mm, 1.35 mm, 1.4 mm, 1.45 mm, 1.5 mm, or any two of these values; the diameter can be 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, 2 mm, or any two of these values; and the height can be 3.5 mm, 3.6 mm, 3.7 mm, 4 mm, 4.2 mm, 4.5 mm, or any two of these values.

[0076] This embodiment increases the contact area between the heat dissipation substrate and the external environment by reasonably setting the spacing, diameter, and height of adjacent cylindrical heat dissipation columns, thereby ensuring that the heat dissipation substrate has good heat dissipation efficiency.

[0077] Meanwhile, in the above embodiment, the heat dissipation column 220 is configured as a cylindrical heat dissipation column; of course, the heat dissipation column 220 can also be configured as a prismatic shape (e.g., Figure 3 and Figure 4 (as shown) or other shapes.

[0078] Reference Figure 1As shown, in some embodiments, a metal compound layer 300 is formed between the heat dissipation aluminum plate 210 and the copper substrate 100; the thickness of the metal compound layer 300 is less than or equal to 1 micrometer, the peel strength of the metal compound layer 300 is greater than or equal to 110 Newtons / mm, and the shear strength of the metal compound layer 300 is greater than or equal to 60 MPa.

[0079] In order to ensure that the metal compound layer 300 can maintain a good bonding strength between the copper substrate 100 and the heat dissipation aluminum plate 210, the thickness of the metal compound layer 300 is limited in this embodiment, and the thickness should be less than or equal to 1 micrometer.

[0080] When the copper substrate 100 and the heat dissipation aluminum plate 210 are combined, mutual diffusion and reaction will occur at the contact surface between the two to form a metal compound layer 300. Since the hardness of the metal compound layer 300 is much higher than that of the copper substrate 100 and the heat dissipation aluminum plate 210, the thicker metal compound layer 300 will become a stress concentration point. Especially during thermal cycling, the shear stress generated by the mismatch of the thermal expansion coefficients of the copper substrate 100 and the heat dissipation aluminum plate 210 will cause the metal compound layer 300 to break, causing the copper substrate 100 and the heat dissipation aluminum plate 210 to separate.

[0081] Therefore, in specific implementation, the heat dissipation structure 200 is formed on the copper substrate 100 through a casting and rolling process, which can control the thickness of the metal compound layer 300 within 1 micrometer, so that the metal compound layer 300 is not easily broken, improves the bonding strength between the copper substrate 100 and the heat dissipation aluminum plate 210, and extends the service life of the heat dissipation substrate.

[0082] Reference Figures 1 to 6 As shown, a second aspect of this application provides a method for preparing a heat dissipation substrate, the method comprising:

[0083] S101, Provide copper substrate 100.

[0084] Specifically, the contact surfaces of the copper substrate 100 and the heat dissipation aluminum plate 210 need to be pre-polished to remove the oxide layer on the surface of the copper substrate 100 and expose the unoxidized fresh copper metal so that mutual diffusion and reaction can occur when it is combined with the heat dissipation aluminum plate 210; and the surface roughness of the copper substrate 100 after pre-polishing should be controlled between 0.5 micrometers and 1.5 micrometers.

[0085] S102. A heat dissipation structure foundation is formed on the surface of the copper substrate 100 by a casting and rolling process. The copper substrate 100 and the heat dissipation structure foundation together form a heat dissipation substrate foundation.

[0086] S103. Process the foundation of the heat dissipation structure to form the heat dissipation structure 200.

[0087] The heat dissipation structure 200 includes a heat dissipation aluminum plate 210 and a plurality of heat dissipation columns 220. The heat dissipation aluminum plate 210 is connected to the surface of the copper substrate 100, and the heat dissipation columns 220 are disposed on the surface of the heat dissipation aluminum plate 210 away from the copper substrate 100.

[0088] In some embodiments, a heat dissipation structure foundation is formed on the surface of a copper substrate 100 by a casting and rolling process, including: casting an aluminum layer on the surface of the copper substrate 100; rolling the aluminum layer to form a heat dissipation structure foundation; during the casting process of forming the aluminum layer, the casting speed is greater than or equal to 0.1 m / s and less than or equal to 0.3 m / s; the casting temperature is greater than or equal to 680 degrees Celsius and less than or equal to 700 degrees Celsius; and the casting time is greater than or equal to 0.1 seconds and less than or equal to 0.3 seconds.

[0089] For example, the pouring speed can be 0.1 m / s, 0.15 m / s, 0.2 m / s, 0.25 m / s, 0.3 m / s, or any range between two values.

[0090] This embodiment avoids turbulence in the molten aluminum during the pouring process by setting a reasonable pouring speed, ensuring that the flow velocity deviation at the slot outlet is less than 5%. At this time, the molten aluminum can form a stable laminar flow and be poured onto the surface of the copper substrate 100, thereby improving the quality and reliability of the heat dissipation substrate.

[0091] For example, the pouring temperature can be 680 degrees Celsius, 685 degrees Celsius, 690 degrees Celsius, 695 degrees Celsius, 700 degrees Celsius, or any range between two values.

[0092] In this embodiment, by setting a reasonable pouring temperature, the aluminum liquid is ensured to be in a molten state during the pouring process. The molten aluminum liquid has ultra-high atomic activity and can completely wet the surface of the copper substrate 100. At the same time, the molten aluminum liquid has good fluidity and plasticity.

[0093] For example, the pouring time can be 0.1 seconds, 0.15 seconds, 0.2 seconds, 0.25 seconds, 0.3 seconds, or any range between two values.

[0094] This embodiment uses a reasonably set pouring time to complete the wetting, crystallization, and composite process in a very short time, avoiding excessive growth of brittle phases such as CuAl2, which would affect the bonding strength between the copper substrate 100 and the heat dissipation aluminum plate 210.

[0095] In practice, before casting an aluminum layer onto the surface of the copper substrate 100, it is necessary to melt aluminum ingots or other aluminum raw materials to obtain molten aluminum.

[0096] Argon or other inert gases are introduced into the molten aluminum to form bubbles. These bubbles adsorb hydrogen and inclusions in the molten aluminum and rise to the surface, thus refining the aluminum. The refining temperature should be controlled between 720 and 740 degrees Celsius, and the argon flow rate should be controlled between 0.75 cubic meters per hour and 1 cubic meter per hour.

[0097] Subsequently, a grain refiner is added to the molten aluminum. Common grain refiners are titanium boron grain refiners. Titanium boron grain refiners form heterogeneous nucleation sites in the molten aluminum, promoting heterogeneous nucleation of grains and inhibiting their growth, so that the grains remain fine and uniform, and improving the tensile strength and elongation of the molten aluminum during solidification. The addition rate of the grain refiner should be controlled between 1.5 cm / min and 2.5 cm / min.

[0098] After refining and purifying, the molten aluminum is passed into the front chamber for cooling until it reaches the preset casting temperature. The liquid level in the front chamber should be controlled between 56 mm and 60 mm, and the temperature of the molten aluminum should be controlled between 700 degrees Celsius and 740 degrees Celsius.

[0099] Finally, the molten aluminum in the front chamber is transported to the casting nozzle distribution chamber through the guide tube at a flow rate of 30 mm / s to 50 mm / s. The guide tube is covered with inert gases such as argon throughout to isolate air and prevent oxidation of the molten aluminum. The distribution chamber is equipped with a honeycomb rectifier grid, and the molten aluminum is extruded from the slot outlet at a speed of 0.1 m / s to 0.3 m / s and poured onto the surface of the copper substrate 100.

[0100] Furthermore, in some embodiments, rolling an aluminum layer to form a heat dissipation structure base includes: rolling the surface of the copper substrate 100 away from the heat dissipation structure base with a first roll; rolling the surface of the heat dissipation structure base away from the copper substrate 100 with a second roll, wherein the surface roughness of the first roll is less than the surface roughness of the second roll; during the rolling of the aluminum layer, the rolling temperature is greater than or equal to 160 degrees Celsius and less than or equal to 200 degrees Celsius; the rolling pressure is greater than or equal to 240 kN and less than or equal to 300 kN; and the rolling speed is greater than or equal to 3 m / min and less than or equal to 5 m / min.

[0101] For example, the rolling temperature can be 160 degrees Celsius, 165 degrees Celsius, 170 degrees Celsius, 175 degrees Celsius, 180 degrees Celsius, 185 degrees Celsius, 190 degrees Celsius, 195 degrees Celsius, 200 degrees Celsius, or any range between two values.

[0102] This embodiment reasonably limits the rolling temperature. When the rolling temperature is less than 160 degrees Celsius, the aluminum melt will solidify too quickly, causing cracks to appear on the surface of the heat dissipation structure base. When the rolling temperature is greater than 200 degrees Celsius, the first roll and the second roll are prone to thermal fatigue and cracking.

[0103] For example, the rolling pressure can be 240 kN, 245 kN, 250 kN, 255 kN, 260 kN, 265 kN, 270 kN, 275 kN, 285 kN, 300 kN, or any range between two values.

[0104] This embodiment uses a reasonably set rolling pressure to break the oxide film on the surface of the aluminum layer, thereby promoting the metallurgical bonding between the aluminum layer and the copper substrate 100.

[0105] For example, the rolling rate can be 3 m / min, 3.5 m / min, 4 m / min, 4.5 m / min, 5 m / min, or any range between two values.

[0106] This embodiment reduces the thickness of the oxide film on the aluminum layer surface while lowering the porosity of the bonding layer between the aluminum layer and the copper substrate 100 by reasonably setting the rolling rate.

[0107] In practice, the first roll contacts the surface of the copper substrate 100, and the second roll contacts the surface of the heat dissipation aluminum plate 210. The surface roughness of the first roll is set to be less than that of the second roll. By utilizing the difference in surface roughness between the first roll and the second roll, the rolling speed of the first roll and the second roll is different, which generates a frictional shear force between the copper substrate 100 and the heat dissipation aluminum plate 210. This breaks the oxide layer on the contact surface of the copper substrate 100 and the heat dissipation aluminum plate 210, promotes the interdiffusion of copper atoms and aluminum atoms, improves the bonding strength between the copper substrate 100 and the heat dissipation aluminum plate 210, and extends the service life of the heat dissipation substrate.

[0108] Furthermore, in some embodiments, after rolling the aluminum layer to form the heat dissipation structure base, the process further includes: annealing the heat dissipation substrate base; the annealing temperature is greater than or equal to 195 degrees Celsius and less than or equal to 205 degrees Celsius; the annealing time is greater than or equal to 415 minutes and less than or equal to 425 minutes.

[0109] For example, the annealing temperature can be 195 degrees Celsius, 196 degrees Celsius, 197 degrees Celsius, 198 degrees Celsius, 200 degrees Celsius, 202 degrees Celsius, 204 degrees Celsius, 205 degrees Celsius, or any range between two values.

[0110] This embodiment, through a reasonably set annealing temperature, can balance recrystallization, improve the stability of the bonding layer between the heat dissipation structure base and the copper substrate 100, and eliminate residual stress generated during the above processing.

[0111] For example, the annealing time can be 415 minutes, 416 minutes, 417 minutes, 418 minutes, 420 minutes, 422 minutes, 424 minutes, 425 minutes, or any range between two values.

[0112] This embodiment achieves the effect of eliminating residual stress generated during the above processing by reasonably setting the annealing time and working in synergy with the annealing temperature, thereby improving the stability of the bonding layer between the heat dissipation structure base and the copper substrate 100.

[0113] In practice, annealing the heat dissipation substrate base can remove residual stress within the heat dissipation substrate base and ensure the shear strength of the metal compound layer.

[0114] Reference Figures 1 to 6 As shown, in some embodiments, processing the heat dissipation structure foundation to form heat dissipation structure 200 includes:

[0115] S201, cold forged heat dissipation structure foundation, part of the heat dissipation structure foundation forms a heat dissipation aluminum plate foundation, and the remaining part of the heat dissipation structure foundation forms multiple heat dissipation column foundations.

[0116] Specifically, the heat dissipation structure base is forced to form within the mold cavity by the forging pressure of 2200 to 2400 tons using a mold. The edge of the heat dissipation structure base forms a heat dissipation aluminum plate base, and the middle of the heat dissipation structure base forms multiple heat dissipation column bases.

[0117] Similarly, targeting Figure 3 and Figure 4 The prismatic heat dissipation column 220 can be shaped by workers using a grooving process.

[0118] S202, Cutting and processing the heat dissipation column foundation.

[0119] Specifically, the heat dissipation column base is cut using a horizontal side-cutting special column cutting machine to achieve the preset diameter, height, and spacing of the heat dissipation column 220; the heat dissipation substrate base is milled using CNC machining to obtain the required shape and structural dimensions; and the oil and dirt on the surface of the heat dissipation substrate base are cleaned using ultrasonic cleaning.

[0120] S203, Basic structure for heat dissipation in heat treatment.

[0121] Specifically, the heat dissipation structure foundation is subjected to a second annealing to further remove residual stress within the foundation. The annealing temperature should be controlled between 190 degrees Celsius and 210 degrees Celsius, and the annealing time should be controlled between 1 hour and 2 hours.

[0122] S204. Surface-treated heat dissipation substrate base to form a heat dissipation substrate; the surface roughness of the heat dissipation substrate is greater than or equal to 0.6 micrometers and less than or equal to 1.2 micrometers.

[0123] For example, the surface roughness can be 0.6 micrometers, 0.7 micrometers, 0.8 micrometers, 0.9 micrometers, 1 micrometer, 1.1 micrometers, 1.2 micrometers, and any range between two values.

[0124] Specifically, zirconium sand is sprayed onto the surface of the heat dissipation substrate to remove the oxide layer on the surface of the heat dissipation substrate; nickel is plated onto the surface of the heat dissipation substrate to enhance its corrosion resistance and solderability. The thickness of the nickel layer can be designed according to the usage environment of the heat dissipation substrate and is not limited here.

[0125] The present application will be further described below through specific embodiments. In the following embodiments and comparative examples, the copper substrate is a copper plate with a length of 153 mm, a width of 73 mm, and a thickness of 2 mm, and the grade is T2.

[0126] Example 1

[0127] The heat dissipation substrate consists of a copper substrate and a heat dissipation aluminum plate connected to one side of the copper substrate, with the same length and width as the copper substrate. The thickness of the heat dissipation aluminum plate is 1.5 mm. Multiple cylindrical heat dissipation columns are arranged on the surface of the heat dissipation aluminum plate away from the copper substrate. The diameter of the cylindrical heat dissipation column is 1.7 mm, the height of the cylindrical heat dissipation column is 3.9 mm, and the distance between two adjacent cylindrical heat dissipation columns is 1.35 mm.

[0128] The method for preparing this heat dissipation substrate includes the following steps:

[0129] (1) Metallic aluminum is poured onto the surface of a copper substrate to obtain an aluminum layer with a thickness of 2.2 mm. During the pouring process, the pouring speed is 0.2 m / s, the pouring temperature is 690 degrees Celsius, and the pouring time is 0.2 seconds.

[0130] (2) The aluminum layer is rolled to obtain a heat dissipation structure base with a thickness of 1.9 mm. The copper substrate and the heat dissipation structure base together form a heat dissipation substrate base. During the rolling process, the rolling temperature is 180 degrees Celsius, the rolling pressure is 260 kN, and the rolling speed is 4 m / min.

[0131] (3) The heat dissipation substrate is annealed for the first time at a temperature of 200 degrees Celsius for 420 minutes.

[0132] (4) The heat dissipation structure foundation is cold-forged to obtain a heat dissipation aluminum plate foundation with a thickness of 1.5 mm and a cylindrical heat dissipation column foundation with a diameter of 1.7 mm and a height of 4.1 mm. The distance between two adjacent cylindrical heat dissipation column foundations is 1.35 mm.

[0133] (5) Cut the cylindrical heat sink base to obtain a cylindrical heat sink with a diameter of 1.7 mm and a height of 3.9 mm; mill the heat sink base to remove excess material; and clean the surface of the heat sink base with ultrasonic waves.

[0134] (6) The heat dissipation structure base is annealed for the second time at a temperature of 200 degrees Celsius for 60 minutes.

[0135] (7) Spray zircon sand onto the surface of the heat dissipation substrate base, and the surface roughness after zircon sand spraying is 0.9 micrometers; plate nickel onto the surface of the heat dissipation substrate base, and the nickel layer thickness is 0.005 millimeters to obtain the heat dissipation substrate.

[0136] Example 2

[0137] The preparation method of the heat dissipation substrate in this comparative example is basically the same as that in Example 1, except that the pouring speed is 0.1 m / s, the pouring temperature is 680 degrees Celsius, and the pouring time is 0.1 seconds.

[0138] Example 3

[0139] The preparation method of the heat dissipation substrate in this comparative example is basically the same as that in Example 1, except that the pouring speed is 0.3 m / s, the pouring temperature is 700 degrees Celsius, and the pouring time is 0.3 seconds.

[0140] Example 4

[0141] The preparation method of the heat dissipation substrate in this comparative example is basically the same as that in Example 1, except that the rolling temperature is 160 degrees Celsius, the rolling pressure is 240 kN, and the rolling speed is 3 m / min.

[0142] Example 5

[0143] The preparation method of the heat dissipation substrate in this comparative example is basically the same as that in Example 1, except that the rolling temperature is 200 degrees Celsius, the rolling pressure is 300 kN, and the rolling speed is 5 m / min.

[0144] Example 6

[0145] The preparation method of the heat dissipation substrate in this comparative example is basically the same as that in Example 1, except that the annealing temperature is 195 degrees Celsius and the annealing time is 415 minutes.

[0146] Example 7

[0147] The preparation method of the heat dissipation substrate in this comparative example is basically the same as that in Example 1, except that the annealing temperature is 205 degrees Celsius and the annealing time is 425 minutes.

[0148] Comparative Example 1

[0149] The preparation method of the heat dissipation substrate in this comparative example is basically the same as that in Example 1, except that the pouring speed is 0.4 m / s, the pouring temperature is 710 degrees Celsius, and the pouring time is 0.4 seconds.

[0150] Comparative Example 2

[0151] The preparation method of the heat dissipation substrate in this comparative example is basically the same as that in Example 1, except that the rolling temperature is 220 degrees Celsius, the rolling pressure is 320 kN, and the rolling speed is 6 m / min.

[0152] Comparative Example 3

[0153] The preparation method of the heat dissipation substrate in this comparative example is basically the same as that in Example 1, except that the heat dissipation substrate base is not annealed.

[0154] Comparative Example 4

[0155] The preparation method of the heat dissipation substrate in this comparative example is basically the same as that in Example 1, except that the annealing temperature is 210 degrees Celsius and the annealing time is 430 minutes.

[0156] Experimental Example 1

[0157] The thickness, peel strength, and shear strength of the metal compound layers obtained in the preparation of heat dissipation substrates in Examples 1-7 and Comparative Examples 1-4 were measured. The thickness was measured by metallographic microscopy, the peel strength was measured by a 90-degree peel test, and the shear strength was measured by a universal testing machine. The results are shown in Table 1.

[0158] Table 1

[0159]

[0160]

[0161] As shown in Table 1:

[0162] 1. As can be seen from Example 1 and Comparative Example 1, the pouring speed, pouring temperature and pouring time affect the peel strength and shear strength of the metal compound layer. When the appropriate pouring speed, pouring temperature and pouring time are selected and matched with each other, aluminum atoms can be fully diffused to the surface of the copper substrate, thereby obtaining a metal compound layer with higher peel strength and shear strength.

[0163] 2. As can be seen from Example 1 and Comparative Example 2, rolling speed, rolling temperature and rolling time affect the peel strength and shear strength of the metal compound layer. When appropriate rolling speed, rolling temperature and rolling time are selected and matched with each other, the grain deformation between the aluminum layer and the copper substrate can be fully achieved, thereby obtaining a metal compound layer with higher peel strength and shear strength.

[0164] 3. As can be seen from Example 1 and Comparative Example 3, when the heat dissipation substrate is not annealed, the shear strength of the metal compound layer is significantly worse, indicating that the annealing process is indispensable.

[0165] 4. As can be seen from Example 1 and Comparative Example 4, annealing temperature and annealing time affect the peel strength and shear strength of the metal compound layer. When a suitable annealing temperature and annealing time are selected and matched with each other, the internal stress of the heat dissipation substrate can be effectively eliminated, thereby obtaining a metal compound layer with higher peel strength and shear strength.

[0166] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the embodiments of this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in the embodiments of this application can be achieved, and this document does not impose any restrictions.

[0167] The specific embodiments described above do not constitute a limitation on the scope of protection of the embodiments of this application. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the principles of the embodiments of this application should be included within the scope of protection of the embodiments of this application.

Claims

1. A method for preparing a heat dissipation substrate, characterized in that, include: A copper substrate (100) is provided. A heat dissipation structure foundation is formed on the surface of the copper substrate (100) by a casting and rolling process, and the copper substrate (100) and the heat dissipation structure foundation together form a heat dissipation substrate foundation. The foundation of the heat dissipation structure is processed to form a heat dissipation structure (200). The heat dissipation structure (200) includes a heat dissipation aluminum plate (210) and a plurality of heat dissipation columns (220). The heat dissipation aluminum plate (210) is connected to the surface of the copper substrate (100), and the heat dissipation columns (220) are disposed on the surface of the heat dissipation aluminum plate (210) away from the copper substrate (100). The process of forming a heat dissipation structure foundation on the surface of the copper substrate (100) through casting and rolling includes: An aluminum layer is cast onto the surface of the copper substrate (100); The aluminum layer is rolled to form the basis of the heat dissipation structure. During the process of casting to form the aluminum layer, the casting speed is greater than or equal to 0.1 m / s and less than or equal to 0.3 m / s; the casting temperature is greater than or equal to 680 degrees Celsius and less than or equal to 700 degrees Celsius; and the casting time is greater than or equal to 0.1 seconds and less than or equal to 0.3 seconds.

2. The method for preparing a heat dissipation substrate according to claim 1, characterized in that, The rolling of the aluminum layer to form the basis of the heat dissipation structure includes: The surface of the copper substrate (100) away from the base of the heat dissipation structure is rolled by the first roll; The surface of the heat dissipation structure base away from the copper substrate (100) is rolled by a second roll, and the surface roughness of the first roll is less than that of the second roll. During the rolling process of the aluminum layer, the rolling temperature is greater than or equal to 160 degrees Celsius and less than or equal to 200 degrees Celsius; the rolling pressure is greater than or equal to 240 kN and less than or equal to 300 kN; and the rolling speed is greater than or equal to 3 m / min and less than or equal to 5 m / min.

3. The method for preparing a heat dissipation substrate according to claim 1, characterized in that, After rolling the aluminum layer to form the basis of the heat dissipation structure, the preparation method further includes: The heat dissipation substrate is annealed; the annealing temperature is greater than or equal to 195 degrees Celsius and less than or equal to 205 degrees Celsius; the annealing time is greater than or equal to 415 minutes and less than or equal to 425 minutes.

4. The method for preparing a heat dissipation substrate according to claim 1, characterized in that, The process of processing the foundation of the heat dissipation structure to form the heat dissipation structure (200) includes: The heat dissipation structure foundation described in the cold forging process is partially formed into a heat dissipation aluminum plate foundation, while the remaining part of the heat dissipation structure foundation forms multiple heat dissipation column foundations. The foundation of the heat dissipation column is cut and processed; The heat dissipation structure is based on the heat treatment; The surface of the heat dissipation substrate base is treated to form the heat dissipation substrate; The surface roughness of the heat dissipation substrate is greater than or equal to 0.6 micrometers and less than or equal to 1.2 micrometers.

5. The method for preparing a heat dissipation substrate according to claim 1, characterized in that, The minimum thickness of the heat dissipation aluminum plate (210) is greater than or equal to 0.05 mm and less than or equal to 3 mm.

6. The method for preparing a heat dissipation substrate according to claim 1, characterized in that, The multiple heat dissipation columns (220) are arranged in multiple rows and columns, and the distance between two adjacent heat dissipation columns (220) is greater than or equal to 1.2 mm and less than or equal to 1.5 mm.

7. The method for preparing a heat dissipation substrate according to claim 6, characterized in that, The heat dissipation column (220) is configured as a cylindrical heat dissipation column; The diameter of the cylindrical heat sink is greater than or equal to 1.5 mm and less than or equal to 2 mm; and / or, the height of the cylindrical heat sink is greater than or equal to 3.5 mm and less than or equal to 4.5 mm.

8. The method for preparing a heat dissipation substrate according to any one of claims 1-7, characterized in that, A metal compound layer (300) is formed between the heat dissipation aluminum plate (210) and the copper substrate (100). The thickness of the metal compound layer (300) is less than or equal to 1 micrometer, the peel strength of the metal compound layer (300) is greater than or equal to 60 Newtons / mm, and the shear strength of the metal compound layer (300) is greater than or equal to 60 MPa.

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