Fin radiator and manufacturing method thereof

Abstract

The invention discloses a fin radiator and a manufacturing method thereof, and the method comprises the steps: forming a mask layer on a first surface of a heat dissipation substrate, the first surface comprises a welding region, and the mask layer shields the welding region; forming a first heat dissipation film on the first surface of the heat dissipation substrate through the mask layer; fixing the first surfaces of the plurality of fins on the objective table, and forming second heat dissipation films on the side surfaces and the second surfaces of the fins; and the first surfaces of the fins are fixedly connected with the welding area of the first surface of the heat dissipation substrate through welding. The first heat dissipation film and the second heat dissipation film are respectively formed on the surfaces of the heat dissipation substrate and the fins step by step, and then the heat dissipation substrate and the fins are welded to form the complete fin radiator, so that uniform deposition and efficient interface heat conduction of the graphene-based heat dissipation film are realized.

Description

Technical Field

[0001] This invention relates to the field of radiator technology, and in particular to a finned radiator and its manufacturing method. Background Technology

[0002] Currently, pin-fin copper heat sinks, widely used in power modules, face some challenges in practical applications, limiting their performance in higher-performance scenarios. Firstly, while the thermal conductivity of copper substrates is approximately 400 W / m·K, which is relatively high, it remains insufficient in applications with extremely demanding heat dissipation requirements, such as high-power-density environments like 5G communication equipment and electric vehicles (EVs). This makes it difficult to fully meet the efficient heat dissipation needs of these advanced systems.

[0003] Completely coating the pin-fin surface with a graphene nanocoating of 20-50 nm thickness can effectively improve heat dissipation efficiency, showing a significant performance advantage compared to uncoated structures. However, current graphene coating processes still face significant challenges in achieving highly uniform coating, especially in areas with dense fins where the complex structure and confined space easily lead to significant deposition gradients. These deposition gradients not only result in uneven graphene coating thickness distribution but may also form defects in localized areas, further exacerbating interfacial thermal resistance issues.

[0004] Therefore, optimizing the graphene coating process to overcome these technical challenges is key to improving the performance of Pin-Fin heat sinks. Summary of the Invention

[0005] In view of the above problems, the purpose of the present invention is to provide a finned heat sink and a method for manufacturing the same, wherein a first heat dissipation film and a second heat dissipation film are formed on the surface of the heat dissipation substrate and the fins respectively in steps, and then the heat dissipation substrate and the fins are welded to form a complete finned heat sink, thereby achieving uniform deposition of graphene-based heat dissipation film and efficient interfacial heat conduction.

[0006] According to one aspect of the present invention, a method for manufacturing a finned heat sink is provided, comprising: forming a mask layer on a first surface of a heat sink substrate, the first surface including a welding area, the mask layer shielding the welding area; forming a first heat dissipation film on the first surface of the heat sink substrate via the mask layer; fixing the first surfaces of a plurality of fins to a stage, and forming a second heat dissipation film on the side surfaces and second surfaces of the fins; and fixing the first surfaces of the fins to the welding area of ​​the first surface of the heat sink substrate by welding.

[0007] Optionally, the materials of the first heat dissipation film and the second heat dissipation film include graphene layers.

[0008] Optionally, the step of forming a first heat dissipation film on the first surface of the heat dissipation substrate via the mask layer includes: depositing a graphene layer on the first surface of the heat dissipation substrate using chemical vapor deposition, wherein the graphene layer is deposited only on the non-soldering area of ​​the first surface of the heat dissipation substrate under the cover of the mask layer; and removing the mask layer.

[0009] Optionally, the material of the mask layer includes high-temperature resistant polyimide tape.

[0010] Optionally, the projection of the mask layer on the first surface of the heat dissipation substrate completely covers the soldering area, and the soldering area is located in the projection of the mask layer; the projection edge of the mask layer is a first distance away from the edge of the soldering area.

[0011] Optionally, the first distance is not less than 2 mm.

[0012] Optionally, the step of fixing the first surface of multiple fins to a stage and forming a second heat dissipation film on the side and second surfaces of the fins includes: fixing the first surface of multiple fins to a stage, maintaining a uniform spacing between adjacent fins; forming a second heat dissipation film on the side and second surfaces of the fins using a deposition process; and separating the stage from the fins.

[0013] Optionally, the second heat dissipation film extends continuously along the direction from the second surface to the first surface on the side surface of the fin, and the edge of the second heat dissipation film on the side surface of the fin near the first surface is a second distance away from the edge of the first surface of the fin.

[0014] Optionally, the second distance is not less than 1 mm.

[0015] According to another aspect of the present invention, a finned heat sink is provided, formed by the above-described manufacturing method, comprising: a heat sink substrate and a plurality of fins, wherein a first surface of the fins is fixedly connected to a welding area of ​​the first surface of the heat sink substrate; a first heat dissipation film is located on the first surface of the heat sink substrate; and a second heat dissipation film is located on the side surface and the second surface of the fins.

[0016] The finned heat sink and its manufacturing method provided by this invention form a first heat dissipation film on a heat dissipation substrate and a second heat dissipation film on the fin surface in steps, and then weld the heat dissipation substrate and fins to form a complete finned heat sink. This achieves uniform deposition of the graphene-based heat dissipation film and efficient interfacial thermal conduction, effectively reducing interfacial thermal resistance and improving overall heat dissipation performance. This method avoids the coating unevenness problem caused by the complex structure in traditional CVD processes, ensuring the continuity and integrity of the graphene layer on the fin surface and the substrate.

[0017] Furthermore, in the finned heat sink and its manufacturing method of this application, when the first heat dissipation film and the second heat dissipation film are formed in steps, a mask layer is used to protect the welding area on the first surface of the heat dissipation substrate to prevent graphene from being deposited in the welding area. The second heat dissipation film is not deposited on the side of the fins close to the stage, thereby ensuring that the heat dissipation film will not affect the welding area during subsequent welding, thereby improving the reliability and bonding strength of the finned heat sink. Attached Figure Description

[0018] The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0019] Figure 1 A schematic diagram of a finned heat sink according to an embodiment of the present invention is shown;

[0020] Figure 2 A flowchart illustrating a method for manufacturing a finned heat sink according to an embodiment of the present invention is shown;

[0021] Figures 3a to 3d Cross-sectional views of each stage of the manufacturing method of the finned heat sink according to an embodiment of the present invention are shown. Detailed Implementation

[0022] Various embodiments of the invention will now be described in more detail with reference to the accompanying drawings. In the various drawings, the same elements are indicated by the same or similar reference numerals. For clarity, the various parts in the drawings are not drawn to scale.

[0023] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0024] Figure 1 A schematic diagram of a finned heat sink according to an embodiment of the present invention is shown.

[0025] like Figure 1 As shown, the finned heat sink 100 of this application includes a heat sink substrate 110, a plurality of fins 120 arranged in an array, and a heat sink film 130 located on the first surface S1 of the heat sink substrate 110 and the surface of the fins 120.

[0026] Specifically, refer to Figure 1 In part (a), the heat dissipation film 130 includes a first heat dissipation film and a second heat dissipation film, wherein the first heat dissipation film is located on the first surface S1 of the heat dissipation substrate 110, and the second heat dissipation film covers the surface of the fin 120, including the side surface and the second surface S2 of the fin 120. The first surface S1 of the fin 120 is connected to the first surface S1 of the heat dissipation substrate 110.

[0027] In the finned heat sink 100, the cross-sectional shape of the fins 120 along the direction of the first surface S1 of the heat sink substrate 110 includes circles, ellipses, rectangles, squares and other polygons.

[0028] exist Figure 1 In the illustrated embodiment, the cross-sectional shape of the fin 120 is, for example, circular, i.e., a pin-fin heat dissipation fin of different shapes such as barrel, cylinder, or cone. The cross-sectional diameter of the fin 120 ranges from 1 mm to 5 mm, the height of the fin 120 (the distance between the first surface and the second surface) is 3-10 mm, and the spacing between adjacent fins is 3-8 mm.

[0029] In the finned heat sink 100, the first surface S1 of the heat dissipation base plate 110 is the main heat dissipation surface, which is fixedly connected to multiple fins 120. This allows the heat generated by the heat-generating element to be conducted to the fins 120. Then, the fins 120 dissipate the heat through convective heat exchange with the flowing air or cooling fluid, and may also dissipate some heat through radiation. The presence of the fins 120 significantly increases the contact area between the heat sink and the surrounding medium, thereby enhancing the convective and radiative heat exchange effects and improving the overall heat dissipation efficiency.

[0030] Furthermore, the heat dissipation film 130 is made of graphene, which has excellent thermal conductivity and thermal stability, effectively reducing interfacial thermal resistance and improving heat dissipation efficiency. Therefore, the finned heat sink 100 with the heat dissipation film 130 can maintain stable heat dissipation performance even under high-temperature operating conditions. When using the finned heat sink 100, the high thermal conductivity of graphene allows heat to rapidly diffuse from the surface of the fins 120 and the first surface of the heat dissipation substrate 110 to the heat dissipation film 130, and then diffuse across the surface of the heat dissipation film 130, promoting efficient heat exchange between the fins 120 and the air or coolant.

[0031] In this embodiment, the finned heat sink 100 is formed, for example, by welding a heat sink substrate 110 and a plurality of needle-shaped fins 120. Before welding, a first heat dissipation film is formed on the first surface S1 of the heat sink substrate 110 and a second heat dissipation film is formed on the surface of each fin 120. Then the two are welded together to form a complete finned heat sink 100.

[0032] The finned heat sink 100 formed in this way can ensure that the first and second heat dissipation films formed in stages have good thickness uniformity and quality. At the same time, the heat dissipation film is not formed in the welding area, which avoids the influence of the heat dissipation film on the welding area, improves the welding quality of the weld joint, and is more conducive to improving the overall structural strength, reliability and heat dissipation performance.

[0033] Figure 2 A flowchart illustrating a method for manufacturing a finned heat sink according to an embodiment of the present invention is shown; Figures 3a to 3d Cross-sectional views of each stage of the manufacturing method of the finned heat sink according to an embodiment of the present invention are shown.

[0034] like Figure 2 As shown, the manufacturing method of the finned heat sink 100 includes the following steps.

[0035] Step S10: Form a mask layer on the first surface of the heat dissipation substrate.

[0036] In this step, a mask layer 101 is first deposited on the first surface S1 of the heat dissipation substrate 110. This mask layer 101 defines the film formation area of ​​the first heat dissipation film 131 and reserves the soldering area 111 to prevent the first heat dissipation film 131 from covering the solder joints. The patterning of the mask layer 101 is precisely controlled by photolithography. The patterned mask layer 101 covers the soldering area 111 on the first surface S1 of the heat dissipation substrate 110, exposing the area on the first surface S1 of the heat dissipation substrate 110 where the first heat dissipation film 131 needs to be deposited, such as... Figure 3a As shown.

[0037] Specifically, in this embodiment, the projection of the mask layer 101 on the first surface S1 of the heat dissipation substrate 110 completely covers the welding area 111 and extends outwards to a certain extent, or in other words, the welding area 111 is located within the orthogonal projection range of the mask layer 101, thereby ensuring that the welding area 111 is effectively shielded during the subsequent formation of the first heat dissipation film 131.

[0038] In this embodiment, the projected edge of the mask layer 101 is a first distance D1 away from the edge of the welding area 111, leaving a certain redundant distance to ensure that the first heat dissipation film 131 will not cover the welding area 111 when the first heat dissipation film 131 is deposited.

[0039] In some embodiments, the first distance D1 is not less than 2 mm. The first distance D1 is preferably 2 mm, which ensures both sufficient redundancy and that the heat dissipation substrate 110 can be coated with a sufficient amount of the first heat dissipation film 131.

[0040] The mask layer 101 can be made of photoresist, metal, or ceramic materials, possessing good high-temperature resistance and chemical stability. In this embodiment, for example, a high-temperature resistant polyimide tape capable of withstanding 1000°C is selected, which can maintain structural integrity and avoid carbonization or peeling during high-temperature CVD, ensuring the cleanliness and solderability of the welding area. The heat dissipation substrate 110 can be made of copper, aluminum, or their alloys, possessing good thermal conductivity and machinability, and maintaining stable physical properties even at high temperatures.

[0041] Step S20: Form a first heat dissipation film on the first surface of the heat dissipation substrate via a mask layer.

[0042] In this step, a first heat dissipation film 131 is formed on the first exposed surface S1 of the heat dissipation substrate 110 using a physical vapor deposition or chemical vapor deposition process, such as... Figure 3b As shown. Due to the shielding effect of the mask layer 101, the first heat dissipation film 131 is deposited only in the area outside the mask layer 101 and has a uniform thickness, effectively avoiding covering the welding area 111.

[0043] After the first heat dissipation film 131 is formed, the mask layer 101 is removed to complete the patterning of the first heat dissipation film 131.

[0044] In this embodiment, the material of the first heat dissipation film 131 is a graphene coating. The first heat dissipation film 131 can be a single-layer or multi-layer structure. When it is a multi-layer structure, the number of layers is, for example, 2-10 layers.

[0045] Through the coordinated control of the mask layer design and deposition process, not only is the precise deposition of the first heat dissipation film 131 in the non-welding area achieved, but the thickness uniformity of the first heat dissipation film 131 and the interfacial bonding strength between the first heat dissipation film 131 and the heat dissipation substrate 110 are also significantly improved, ensuring the long-term reliability of the heat dissipation structure under high temperature, high humidity and thermal cycling working environments.

[0046] Step S30: Fix the first surface of the multiple fins to the stage.

[0047] In this step, the first surfaces of multiple fins 120 are fixed to the stage 102 by vacuum adsorption or mechanical clamping, ensuring that each fin 120 is arranged in a predetermined array on the stage 102 and that the surface flatness is controlled within ±0.05mm. This facilitates the thickness consistency and interface bonding quality during the subsequent formation of the second heat dissipation film. Figure 3c As shown.

[0048] In this embodiment, the first surface of the fin 120 contacts the stage and is firmly fixed, so that the first surface of the fin 120 is completely and naturally shielded, ensuring that the second heat dissipation film 132 is formed only on the non-fixed surface of the fin 120 in subsequent processes.

[0049] Step S40: Form a second heat dissipation film on the side surface and the second surface of the fins.

[0050] In this step, a second heat dissipation film 132 is deposited on the side surface and the second surface of the fin 120 using a directional deposition process. This ensures that the second heat dissipation film 132 uniformly covers the side surface and the second surface of the fin 120, while avoiding deposition on the first surface in contact with the stage 102. Figure 3c As shown.

[0051] Directional deposition is an advanced materials preparation technology that uses precise control of the deposition process of materials (usually atoms or molecules) in a specific direction to create thin films or three-dimensional objects with specific orientations, shapes and structures on a substrate.

[0052] In this embodiment, by precisely controlling the deposition angle and gas flow field distribution, the graphene coating grows only on the exposed surfaces of the fin 120 side surface and the second surface, thereby preserving the integrity of the welding interface. This process, combined with multi-step heating pretreatment in a high-temperature inert atmosphere, effectively improves the crystallinity and adhesion of the graphene layer, while reducing defect density and ensuring a continuous and efficient heat dissipation path.

[0053] In this embodiment, the second heat dissipation film 132 extends continuously on the side surface of the fin 120 along the direction from the second surface to the first surface, and the edge of the second heat dissipation film 132 on the side surface of the fin 120 near the first surface is a second distance D2 from the edge of the first surface of the fin. The second distance D2 is not less than 1mm, which effectively avoids the second heat dissipation film 132 from affecting the welding area 111 during subsequent assembly.

[0054] In this embodiment, the second heat dissipation film 132 also adopts a graphene coating, which is a single-layer or multi-layer structure. When it is a multi-layer structure, the number of layers is, for example, 2-10 layers.

[0055] Specifically, the material composition and structural design of the first heat dissipation film 131 and the second heat dissipation film 132 are consistent to ensure that the first heat dissipation film 131 and the second heat dissipation film 132 perform consistently in terms of thermal conductivity, interface bonding characteristics and environmental tolerance, thereby achieving uniformity and efficiency of heat conduction path in the overall heat dissipation structure.

[0056] Furthermore, after the second heat dissipation film 132 is deposited, the fins 120 are removed from the stage 102 and the first surface is cleaned to remove adsorbed residues or surface contaminants, ensuring the cleanliness of the interface and the reliability of the connection when subsequently soldered to the heat dissipation substrate 110.

[0057] Step S50: Fix the first surface of the fins to the welding area of ​​the first surface of the heat sink substrate.

[0058] In this step, laser micro-welding technology can be used to fix the first surface of the fin 120 to the welding area 111 of the heat dissipation substrate 110, such as... Figure 3d As shown.

[0059] In this embodiment, the welding parameters for laser micro-welding include a fiber laser wavelength of 1070nm, a pulse energy of 15J, a frequency of 500Hz, and a defocusing amount of +0.5mm, ensuring a moderate weld depth and a narrow heat-affected zone, thereby avoiding problems such as material cracking caused by thermal stress between the heat dissipation film 130 and the heat dissipation substrate 110.

[0060] Among them, the welded finned heat sink 100 has excellent structural stability and thermal conductivity. The welded interface is firmly bonded and there are no obvious defects such as pores or cracks. The porosity of the weld point is less than 3% in X-ray inspection. Infrared thermal imaging shows that the temperature rise in the welded area is uniform and there is no local overheating phenomenon.

[0061] The finned heat sink and its manufacturing method provided by this invention form a first heat dissipation film on a heat dissipation substrate and a second heat dissipation film on the fin surface in steps, and then weld the heat dissipation substrate and fins to form a complete finned heat sink. This achieves uniform deposition of the graphene-based heat dissipation film and efficient interfacial thermal conduction, effectively reducing interfacial thermal resistance and improving overall heat dissipation performance. This method avoids the coating unevenness problem caused by the complex structure in traditional CVD processes, ensuring the continuity and integrity of the graphene layer on the fin surface and the substrate.

[0062] Furthermore, in the finned heat sink and its manufacturing method of this application, when the first heat dissipation film and the second heat dissipation film are formed in steps, a mask layer is used to protect the welding area on the first surface of the heat dissipation substrate to prevent graphene from being deposited in the welding area. The second heat dissipation film is not deposited on the side of the fins close to the stage, thereby ensuring that the heat dissipation film will not affect the welding area during subsequent welding, thereby improving the reliability and bonding strength of the finned heat sink.

[0063] As described above, these embodiments of the present invention do not exhaustively cover all details, nor do they limit the invention to the specific embodiments described. Clearly, many modifications and variations can be made based on the above description. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to effectively utilize the invention and its modifications. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for manufacturing a finned heat sink, comprising: forming a mask layer on a first surface of a heat dissipation substrate, the first surface comprising a soldering area, the mask layer shielding the soldering area; forming a first heat dissipation film on the first surface of the heat dissipation substrate via the mask layer; fixing a first surface of a plurality of fins on a stage, and forming a second heat dissipation film on side surfaces and a second surface of the fins; fixing and connecting the first surface of the fins and the soldering area of the first surface of the heat dissipation substrate.

2. The manufacturing method according to claim 1, wherein, The first heat dissipation film and the second heat dissipation film comprise a graphene layer.

3. The manufacturing method according to claim 2, wherein, The step of forming a first heat dissipation film on the first surface of the heat dissipation substrate via the mask layer comprises: depositing a graphene layer on the first surface of the heat dissipation substrate by chemical vapor deposition, under the shielding of the mask layer, the graphene layer is only deposited on the non-soldering area of the first surface of the heat dissipation substrate; removing the mask layer.

4. The manufacturing method according to claim 3, wherein, The mask layer comprises a high-temperature-resistant polyimide tape.

5. The manufacturing method according to claim 3, wherein, The projection of the mask layer on the first surface of the heat dissipation substrate completely shields the soldering area, and the soldering area is located in the projection of the mask layer. The edge of the projection of the mask layer is at a first distance from the edge of the soldering area.

6. The manufacturing method according to claim 5, wherein, The first distance is not less than 2mm.

7. The production method according to claim 1 or 2, wherein The step of fixing a first surface of a plurality of fins on a stage, and forming a second heat dissipation film on side surfaces and a second surface of the fins comprises: fixing the first surface of the plurality of fins on the stage, and maintaining uniform spacing between adjacent fins; forming a second heat dissipation film on the side surfaces and the second surface of the fins by a deposition process; separating the stage from the fins.

8. The manufacturing method according to claim 7, wherein The second heat dissipation film continuously extends on the side surfaces of the fins in a direction from the second surface to the first surface, and the edge of the second heat dissipation film on the side surface of the fins close to the first surface is at a second distance from the edge of the first surface of the fins.

9. The manufacturing method according to claim 8, wherein, The second distance is not less than 1mm.

10. A finned heat sink, wherein, The method comprises: a heat dissipation substrate and a plurality of fins, the finned heat sink is manufactured by the method according to any one of claims 1-9.

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