Hot plate, power device, power module and electrical equipment
By designing an arc-shaped heat spreader and supporting structure, the problem of warping and deformation after welding was solved, enhancing heat dissipation performance and structural stability, ensuring effective contact between the heat spreader and the radiator, and achieving a highly efficient heat dissipation effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SUNGROW POWER SUPPLY CO LTD
- Filing Date
- 2025-07-15
- Publication Date
- 2026-07-31
AI Technical Summary
After the heat spreader is welded to the semiconductor components, it may warp and deform, resulting in a reduced contact area with the heat dissipation structure. This may lead to defects such as voids in the thermal grease, affecting the heat dissipation effect.
A heat spreader with an arc-shaped structure is designed, with a concave arc surface located on the first surface of the shell. By introducing an initial stress field opposite to the welding deformation in advance, the welding thermal stress is offset. Combined with the support structure and capillary structure, the material selection is optimized to improve the structural stability and heat dissipation performance.
It reduces overall deformation after the heat spreader is welded, enhances the installation stability with semiconductor components, improves heat dissipation performance and structural reliability, ensures effective contact between the heat spreader and the heat sink, and improves the heat dissipation efficiency of power devices.
Smart Images
Figure CN224583720U_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the field of electrical technology, and more specifically, to a heat spreader, a power device, a power module, and electrical equipment. Background Technology
[0002] Power modules are widely used in electrical equipment such as power conversion devices. As the power of power conversion devices increases, the power consumption of semiconductor components in power modules increases significantly, and the requirements for heat dissipation also become more and more stringent. Heat sinks are used in power modules because of their high thermal conductivity and high heat dissipation.
[0003] However, observational studies have revealed that after the heat spreader is soldered to the semiconductor element, the heat spreader warps and deforms, arching towards the semiconductor element. This reduces the contact area between the heat spreader and other heat dissipation structures, such as heat sinks. It can also lead to defects such as voids in the thermal grease between the heat spreader and the heat sink, which in turn affects heat dissipation. Utility Model Content
[0004] This disclosure aims to address, to some extent, the problem of poor heat dissipation caused by warping and deformation of the heat sink after it is connected to the semiconductor element in related technologies.
[0005] To address at least one aspect of the aforementioned problems, in a first aspect, this disclosure provides a heat spreader, comprising a housing and a support structure, wherein the housing encloses a heat spreader cavity, and the support structure is located in the heat spreader cavity and connected to the housing; the heat spreader has an arc-shaped structure, and the concave arc surface of the arc-shaped structure is located on a first surface of the housing, the first surface being the surface of the housing used for welding semiconductor elements.
[0006] Optionally, in at least one direction, the concave arc surface is a surface-symmetrical structure, and the contour line where its symmetrical plane intersects with the concave arc surface is an arc-shaped contour line.
[0007] Optionally, the curvature of the first arc-shaped contour line and the second arc-shaped contour line are consistent. The first arc-shaped contour line is the arc-shaped contour line where the plane of symmetry of the concave arc surface in the second direction intersects with the concave arc surface. The second arc-shaped contour line is the arc-shaped contour line where the plane of symmetry of the concave arc surface in the first direction intersects with the concave arc surface. The second direction is set at an angle to the first direction.
[0008] Optionally, before the heat spreader is bent to form the arc-shaped structure, the first surface is rectangular, and the first direction and the second direction are respectively set to the long side and the short side of the rectangle before the heat spreader is bent; when the long side of the rectangle before the heat spreader is bent is greater than or equal to 50 mm and less than or equal to 300 mm, the first arc height of the first arc contour line is greater than or equal to 0.5 mm and less than or equal to 1.0 mm.
[0009] Optionally, the support structure includes a plurality of columnar structures; the plurality of columnar structures are evenly distributed within the heat exchange cavity;
[0010] And / or, in at least one direction, a plurality of the columnar structures are symmetrically distributed on both sides of the symmetry plane of the concave arc surface.
[0011] Optionally, at least one of the plurality of columnar structures has columnar capillary structures inside or outside.
[0012] Optionally, the heat spreader further includes a capillary structure disposed within the heat spreader cavity;
[0013] When the capillary structure includes only the columnar capillary structure, both ends of the columnar capillary structure are connected to the inner wall surface of the shell respectively;
[0014] When the capillary structure includes a wall-mounted capillary structure and a columnar capillary structure, the wall-mounted capillary structure is attached to the inner wall surface of the housing, one end of the columnar capillary structure is connected to the wall-mounted capillary structure or the inner wall surface, and the other end of the columnar capillary structure is connected to the wall-mounted capillary structure or the inner wall surface.
[0015] Optionally, the housing includes a first housing and a second housing, which are welded together to form the heat exchange cavity.
[0016] Optionally, the wall thickness of the first housing is greater than or equal to the wall thickness of the second housing.
[0017] Optionally, the heat exchange chamber is evacuated; or, the heat exchange chamber is filled with a reducing gas.
[0018] Optionally, the heat spreader is made of copper alloy.
[0019] In a second aspect, this disclosure provides a power device comprising a semiconductor element and a heat spreader as described in any of the first aspects above, wherein the semiconductor element is welded to a first surface of the heat spreader.
[0020] Optionally, after the semiconductor element is welded to the heat spreader, the second side of the heat spreader opposite to the first side has a convex arc surface that protrudes away from the semiconductor element; the second side is used to connect to the heat sink.
[0021] Thirdly, this disclosure provides a power module made of the power device described in any one of the second aspects above, wherein the heat exchange cavity of the power device is provided with a phase change medium.
[0022] Fourthly, this disclosure provides an electrical device including a heat sink and a power module as described in the third aspect above, wherein the second side of the heat sink is connected to the heat sink of the power device of the power module.
[0023] Optionally, the heat spreader and the heat sink are connected by fasteners, and thermal grease, thermal adhesive or thermal gel is applied between the second surface and the heat sink.
[0024] In the heat spreader, power device, power module, and electrical equipment disclosed herein, the heat spreader has an arc-shaped structure. The concave arc surface of the arc-shaped structure is located on the first surface of the housing. The first surface is the surface of the housing used for welding semiconductor components. For example, when the first surface is the upper surface, the mounting area of the semiconductor components on the first surface is lower than the ends, and the two ends are warped. This is equivalent to introducing an initial stress field in the heat spreader in the opposite direction to the welding deformation. During welding, the bending recovery force will partially offset the welding thermal stress. During the cooling process, the residual tensile stress caused by welding needs to be reversed to straighten the arc-shaped structure of the heat spreader (so that the concave arc surface of the arc-shaped structure is straightened). Only when the heat spreader is flat can the mounting area of the semiconductor element on the heat spreader continue to arch towards the semiconductor element. Thus, by setting the heat spreader in this way, the net deformation of the heat spreader after welding can be reduced, and the possibility of the heat spreader bending as a whole after welding the first surface of the heat spreader to the semiconductor element, causing the mounting area of the semiconductor element to arch towards the semiconductor element, is reduced. This is beneficial to ensuring the heat dissipation performance of the final power device (the power device includes the heat spreader and the semiconductor element). The setting of the support structure in the heat spreader cavity of the housing is beneficial to improving the structural performance during the process of bending the heat spreader to form an arc-shaped structure and during welding, and reducing the possibility of excessive or insufficient local deformation of the heat spreader. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the heat spreader structure in an embodiment of this disclosure;
[0026] Figure 2 This is a schematic diagram of the structure of the heat spreader plate before it is bent in an embodiment of this disclosure;
[0027] Figure 3 for Figure 2 Another schematic diagram of the heat spreader shown;
[0028] Figure 4 This is a schematic diagram of the power device structure in an embodiment of this disclosure;
[0029] Figure 5 This is a schematic diagram of the connection between the power module and the heat sink in an embodiment of this disclosure.
[0030] Explanation of reference numerals in the attached figures:
[0031] 1-Shell; 11-First shell; 12-Second shell; 101-Heat dissipation cavity; 2-Support structure; 21-Columnar structure; 211-First columnar structure; 212-Second columnar structure; 3-Capillary structure; 31-Columnar capillary structure; 32-Wall-adhering capillary structure; 311-First wall-adhering capillary structure; 312-Second wall-adhering capillary structure; 4-Semiconductor element; 5-Heat sink; 6-Fastener; 7-Thermal grease; 8-Injection tube; S1-First surface; S2-Second surface; H1-First arc height; L1-First arc contour line; X-First direction; Y-Second direction. Detailed Implementation
[0032] To make the above-described objects, features, and advantages of this disclosure more apparent and understandable, specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. Although some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.
[0033] Those skilled in the art should understand that, unless explicitly stated in the context, or if the context reveals that it has a clear limitation, the following should be understood: the term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments"; the concepts of "first," "second," etc., are used only to distinguish different devices, modules, or units, and are not used to limit the order of functions performed by these devices, modules, or units or their interdependencies, nor should they be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. A feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.
[0034] Furthermore, the illustrative expressions of the terms used in this specification do not necessarily refer to the same embodiments or implementations. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or implementations.
[0035] In the attached figures, the Z-axis represents the vertical direction, i.e., the up-down position, and the positive direction of the Z-axis (i.e., the direction the arrow points) indicates up, and the negative direction of the Z-axis indicates down; the X-axis represents the front-back position, and the positive direction of the X-axis (i.e., the direction the arrow points) indicates the front, and the negative direction of the X-axis indicates the back; the Y-axis represents the horizontal direction and is designated as the left-right position, and the positive direction of the Y-axis (i.e., the direction the arrow points) indicates the right, and the negative direction of the Y-axis indicates the left. It should be noted that the aforementioned representations of the Z-axis, Y-axis, and X-axis are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.
[0036] Power modules are widely used in electrical equipment such as converters. As the power of converters increases, the power consumption of semiconductor components in power modules increases significantly, and the requirements for heat dissipation also become more and more stringent. Heat sinks are used in power modules because of their high thermal conductivity and high heat dissipation.
[0037] After the heat spreader is soldered to the semiconductor component, the heat spreader may warp and deform, arching towards the semiconductor component. This reduces the contact area between the heat spreader and other heat dissipation structures such as heat sinks. It may also cause defects such as voids in the thermal grease between the heat spreader and the heat sink, which in turn affects heat dissipation.
[0038] For example, semiconductor components typically include a chip and a DBC (Direct Bonded Copper) plate. The chip is connected to the DBC plate, which is then soldered to the vapor chamber using solder, usually at high temperatures such as reflow soldering. Temperature variation is a critical factor during reflow soldering. Semiconductor components and vapor chambers are typically composed of different materials. These materials have different coefficients of thermal expansion (CTE), expanding at different rates when heated and contracting inconsistently upon cooling, leading to warping. First, consider the CTE values of each material. For example, copper has a CTE of approximately 17 ppm / °C, Al₂O₃ ceramic approximately 6.5-7 ppm / °C, AlN approximately 4.5 ppm / °C, silicon approximately 2.6 ppm / °C, and solder such as SAC305 approximately 21-25 ppm / °C. Typically, the warping direction of the vapor chamber is dominated by the vapor chamber itself, as the temperature cools from a high temperature (e.g., 250°C) to room temperature during the soldering process. The CTE difference between the heat spreader and the DBC after soldering can cause the heat spreader to warp, deform as a whole, and cause the mounting area of the semiconductor element to arch toward the semiconductor element. As a result, when the side of the heat spreader away from the semiconductor element is connected to the heat sink by means of thermal grease, there may be defects such as voids.
[0039] Specifically, copper has a much higher coefficient of thermal expansion than DBC. When the heat spreader is cooled after being welded to the DBC, the heat spreader's contraction tendency is much greater than that of the DBC. If the heat spreader is thicker and more rigid, or if the DBC is more tightly bonded to the heat spreader in the middle area (weaker at the edges), the heat spreader's contraction will be "restrained" by the DBC in the middle area, but the edge area, due to less constraint, will contract more freely. In this case, the copper in the middle area, especially the copper in the middle area of the heat spreader near the DBC, is "pulled" by the DBC and cannot contract easily, accumulating compressive stress. The copper in the middle area of the heat spreader away from the DBC and the copper in the edge area of the heat spreader contract more fully, forming an arch shape in the middle area of the heat spreader bulging towards the DBC, that is, "the mounting area of the semiconductor element arches towards the semiconductor element."
[0040] like Figure 1 and Figure 4 As shown, in order to at least partially solve the above problems, this disclosure provides a heat spreader, including a housing 1 and a support structure 2. The housing 1 encloses a heat spreader cavity 101, and the support structure 2 is located in the heat spreader cavity 101 and connected to the housing 1. The heat spreader has an arc-shaped structure, and the concave arc surface of the arc-shaped structure is located on the first surface S1 of the housing 1. The first surface S1 is the surface of the housing 1 used for welding with semiconductor element 4.
[0041] It should be understood that the heat spreader forms an arc-shaped structure by bending the entire structure, and the first surface has a mounting area for power devices. For example, when the first surface S1 is the upper surface, the mounting area for power devices is lower than the two ends in the horizontal plane, so that the concave arc surface of the arc-shaped structure is located on the first surface S1 of the housing 1.
[0042] Specifically, the housing 1 typically includes a first housing 11 and a second housing 12, which are welded together to form a heat dissipation cavity 101. The first housing 11 has a first surface S1 for welding to the semiconductor element 4, and the second housing 12 has a second surface S2 for connecting to the heat sink 5.
[0043] It should be understood that, for ease of manufacturing, the overall bending of the heat spreader is usually performed after the first shell 11 and the second shell 12, as well as their internal structures such as the capillary structure 3, have been welded. The overall bending of the heat spreader is usually achieved using relevant equipment and molds, which will not be described here.
[0044] The specific construction and structural form of the support structure 2 are not limited, as long as it can support the shell structure 1 within the heat exchange cavity 101.
[0045] It should be understood that when welding semiconductor element 4 to heat spreader, tooling is required to flatten heat spreader. That is, the arc-shaped structure formed by bending heat spreader as a whole is flattened by applying pressure. At this time, the concave arc surface is pressed into a plane, which makes it easier for semiconductor element 4 and the first surface S1 of housing 1 to obtain a good contact surface during welding.
[0046] Thus, in the embodiments of this disclosure, the heat spreader has an arc-shaped structure, and the concave arc surface of the arc-shaped structure is located on the first surface S1 of the housing 1. The first surface S1 is the surface of the housing 1 used for welding with the semiconductor element 4. For example, when the first surface S1 is the upper surface, the mounting area of the semiconductor element 4 on the first surface S1 is lower than the end, and the two ends are warped. This is equivalent to introducing an initial stress field in the heat spreader in the opposite direction to the welding deformation direction in advance. During welding, the bending recovery force will partially offset the welding thermal stress. During the cooling process, the residual tensile stress caused by welding needs to be reversed to straighten the arc-shaped structure of the heat spreader (so that the concave arc surface of the arc-shaped structure is straightened into a plane) before it is possible to... The mounting area of the semiconductor element 4 on the heat spreader continues to arch towards the semiconductor element 4. Thus, by setting the heat spreader in this way, the net deformation of the heat spreader after welding can be reduced, and the possibility that the overall bending of the heat spreader after welding the first surface S1 of the heat spreader to the semiconductor element 4 will cause the mounting area of the semiconductor element 4 to arch towards the semiconductor element 4 is reduced. This is beneficial to ensuring the heat dissipation performance of the final power device (the power device includes the heat spreader and the semiconductor element 4). The setting of the support structure 2 in the heat spreader cavity 101 of the housing 1 is beneficial to improving the structural performance during the process of bending the heat spreader to form an arc-shaped structure and during welding, and reducing the possibility of excessive or insufficient local deformation of the heat spreader.
[0047] like Figure 1 As shown, optionally, in at least one direction, the concave arc surface is a surface-symmetrical structure, and the contour line where its symmetrical plane intersects with the concave arc surface is an arc-shaped contour line.
[0048] It should be understood that, in a certain direction, the plane of symmetry of the concave arc surface is perpendicular to that direction. For example, in the X-axis direction, the plane of symmetry of the concave arc surface is perpendicular to the X-axis direction, that is, the plane of symmetry of the concave arc surface is parallel to the YZ plane.
[0049] Thus, the symmetrical concave arc surface structure ensures more even stress distribution during pre-bending and welding of the heat spreader, facilitating manufacturing. When subjected to external forces or thermal expansion, the symmetrical structure better resists deformation and reduces localized stress concentration. Simultaneously, the arc contour line, compared to sharp edges or corners, better disperses stress, reducing the risk of cracks or damage due to excessive stress during use. This enhances the overall structural stability and reliability of the heat spreader, enabling it to better adapt to various working environments and conditions.
[0050] like Figure 2 , 3As shown, optionally, the first surface S1 of the heat spreader before bending is rectangular; at least one direction includes a first direction X and / or a second direction Y, the first direction X and the second direction Y being respectively set to the long side and the short side of the rectangle before bending of the heat spreader.
[0051] In this specification, the housing 1 before the heat spreader is bent is generally rectangular. The above-mentioned XYZ coordinate system is established based on this rectangular prism, where the X-axis direction corresponds to the long side direction of the rectangular prism, the Y-axis direction corresponds to the short side direction of the rectangular prism, and the Z-axis direction corresponds to the height direction of the rectangular prism. Correspondingly, the first surface S1 of the heat spreader before bending is generally rectangular. The first direction X can be understood as the X-axis direction, which corresponds to the long side direction of the rectangle before the heat spreader is bent. The second direction Y can be understood as the Y-axis direction, which corresponds to the short side direction of the rectangle before the heat spreader is bent.
[0052] In this way, the concave arc surface can present a symmetrical structure in either the long or short side direction of the rectangle formed by the first surface S1 before bending the heat spreader, or in both the long and short side directions. The heat spreader exhibits good symmetry and structural stability in different directions, facilitating processing and dimensional accuracy control during manufacturing. During bending, symmetrical bending along the long and short side directions is relatively simple and helps ensure the shape consistency of the heat spreader after bending in mass production.
[0053] Optionally, the curvature of the first arc-shaped contour line L1 and the second arc-shaped contour line are consistent. The first arc-shaped contour line L1 is an arc-shaped contour line in which the plane of symmetry of the concave arc surface in the second direction Y intersects with the concave arc surface. The second arc-shaped contour line is an arc-shaped contour line in which the plane of symmetry of the concave arc surface in the first direction X intersects with the concave arc surface. The second direction Y and the first direction X are set at an angle.
[0054] The curvature of the first arc-shaped contour line L1 and the second arc-shaped contour line are consistent. The first arc-shaped contour line L1 is an arc-shaped contour line in which the plane of symmetry of the concave arc surface in the second direction Y intersects with the concave arc surface. The second arc-shaped contour line is an arc-shaped contour line in which the plane of symmetry of the concave arc surface in the first direction X intersects with the concave arc surface.
[0055] Specifically, the first arc-shaped contour line L1, after rotating 180° around its axis of symmetry, covers the second arc-shaped contour line. This results in the entire concave arc surface exhibiting a three-dimensional shape similar to a concave sphere, with the arc height of the first arc-shaped contour line L1 being greater than that of the second arc-shaped contour line. It should be understood that, in this specification, arc height can be understood as the distance between the endpoint and midpoint of the arc-shaped contour line in the Z-axis direction. Arc height reflects the degree of curvature of the arc; when the arc length is the same, the higher the arc height, the greater the degree of curvature of the corresponding arc.
[0056] Thus, the entire concave arc surface presents a three-dimensional shape similar to a concave sphere. This design facilitates manufacturing, improves the production precision and consistency of the vapor chamber, and ensures that the shape and performance of each vapor chamber in mass production meet design requirements. Furthermore, this design enhances the structural stability of the vapor chamber, enabling it to better resist deformation under external forces or thermal expansion, reducing localized stress concentration, and thereby improving the service life and reliability of the vapor chamber.
[0057] In the above embodiments, optionally, the degree of bending of the heat spreader is configured such that after the first surface S1 is welded to the semiconductor element 4, the first surface S1 forms another concave arc surface.
[0058] It should be understood that, after the semiconductor element 4 is welded to the heat spreader, the heat spreader tends to warp and deform as a whole towards the semiconductor element 4. The first surface S1 changes from a concave arc surface before welding to another concave arc surface after welding. The degree of curvature of the concave arc surface before welding is greater than that of the concave arc surface after welding.
[0059] It should be understood that before welding, the shape and contour of the second side S2 of the heat spreader, which is opposite to the first side S1, are consistent with the shape and contour of the first side S1. After welding, the shape and contour of the second side S2 are consistent with the shape and contour of the first side S1. In subsequent use, the second side S2 is usually used to connect with other heat dissipation structures such as the heat sink 5.
[0060] In other words, the degree of curvature of the concave arc surface caused by the overall bending of the heat spreader is configured to be greater than or equal to the degree of curvature of the first surface S1 caused by the welding of the heat spreader to the semiconductor element 4.
[0061] Thus, after the heat spreader is welded to the semiconductor element 4, the first surface S1 still maintains a concave arc surface with a small degree of curvature. As a result, the second surface S2 of the heat spreader, which is opposite to the first surface S1, has a convex arc surface that protrudes outward. After the heat spreader is welded to the semiconductor element 4, for example, when the power module is connected to the heat sink 5 as described later, the convex arc surface helps to spread the thermal grease 7, thermal adhesive, thermal gel, etc. applied between the heat spreader and the heat sink 5, ensuring the heat transfer performance between the heat sink 5 and the power module.
[0062] In the above embodiments, optionally, when the long side of the rectangle before the heat spreader is bent is greater than or equal to 50 mm and less than or equal to 300 mm, the first arc height H1 of the first arc contour line L1 is greater than or equal to 0.5 mm and less than or equal to 1.0 mm. In this case, the second arc height of the second arc contour line is less than the first arc height H1, for example, the second arc height is greater than or equal to 0.35 mm and less than or equal to 0.55 mm.
[0063] In this way, the heat spreader warps as a whole during the welding process. The heat spreader is bent as a whole to counteract the warping that occurs during the high-temperature welding of the heat spreader and the semiconductor element 4, and to retain some curvature. For example, the first arc height H1 after welding is 0.25±0.05mm and the second arc height is 0.1±0.05mm.
[0064] like Figure 1-4 As shown in the above embodiment, optionally, the support structure 2 includes a plurality of columnar structures 21.
[0065] Specifically, the two ends of the columnar structure 21 extend to the inner wall of the shell 1 or to a structure provided on the inner wall, which will be described in detail later with reference to the embodiments.
[0066] Thus, the support structure 2 includes multiple columnar structures 21, which can be used to support the shell 1 in the heat dissipation cavity 101, reducing the possibility of sudden changes in the local shape of the shell 1 during the overall bending of the heat dissipation plate or during the welding of the heat dissipation plate and the semiconductor element 4, and ensuring the yield of the product.
[0067] like Figure 2-4 As shown, in an optional embodiment of the support structure 2, multiple columnar structures 21 are uniformly distributed within the heat exchange cavity 101.
[0068] Specifically, taking the first surface S1 of the heat spreader as a rectangle before bending as an example, multiple columnar structures 21 are arrayed in the heat spreader cavity 101 to achieve a uniform distribution in the heat spreader cavity 101.
[0069] These columnar structures 21 are evenly distributed within the heat exchanger 101, providing a more uniform support force to the housing 1 during the overall bending of the heat exchanger plate or during the welding process with the semiconductor element 4. This reduces the possibility of sudden changes in the local shape of the housing 1, reduces deformation or damage caused by local stress concentration, and reduces the number of columnar structures 21. It also facilitates the layout of the columnar structures 21 in the heat exchanger 101, avoiding excessive occupation of the space of the heat exchanger 101 due to the arrangement of the support structure 2.
[0070] In an alternative embodiment of the support structure 2, a plurality of columnar structures 21 are symmetrically distributed on both sides of the symmetry plane of the concave arc surface in at least one direction.
[0071] For example, in the first direction X, a plurality of columnar structures 21 are symmetrically distributed on both sides of the symmetry plane of the concave arc surface, and in the second direction Y, a plurality of columnar structures 21 are symmetrically distributed on both sides of the symmetry plane of the concave arc surface.
[0072] In this way, by symmetrically distributing multiple columnar structures 21 on both sides of the symmetry plane of the concave arc surface in at least one direction (e.g., the first direction X and the second direction Y), the reliability risk caused by local stress concentration at the symmetry plane during the bending process of the heat spreader or during the welding process with the semiconductor element 4 can be effectively reduced, thereby ensuring the yield and reliability of the product.
[0073] It should be understood that, in the optional configuration of the support structure 2, while multiple columnar structures 21 are evenly distributed within the heat dissipation cavity 101, they can also be symmetrically distributed on both sides of the symmetry plane of the concave arc surface. In other words, while multiple columnar structures 21 are evenly distributed within the heat dissipation cavity 101, columnar structures 21 are avoided at the symmetry plane of the concave arc surface. This not only provides a more uniform supporting force to the shell 1, but also effectively reduces the reliability risk caused by localized stress concentration at the symmetry plane during bending of the heat dissipation plate or during welding with the semiconductor element 4, thereby ensuring product yield and reliability.
[0074] like Figure 1 As shown, optionally, the heat spreader also includes a capillary structure 3, which is disposed in the heat spreader cavity 101.
[0075] When the heat spreader is working, the heat spreader is connected to the semiconductor element 4 and the heat spreader cavity 101 is provided with a phase change medium. The first surface S1 is the side close to the heat source (semiconductor element 4) (evaporation zone), which absorbs heat and causes the liquid phase change medium to evaporate into steam. Under the action of internal pressure, the steam quickly diffuses to the area with a lower temperature (condensation zone), releases heat and condenses back into a liquid state. Then, through the action of the capillary structure 3, the liquid phase change medium is drawn back to the evaporation zone, forming a cycle.
[0076] During this process, the capillary structure 3 serves one or more of the following functions: Liquid reflux: The capillary structure 3 provides the necessary capillary force to carry the condensed liquid back from the condensation zone to the evaporation zone, ensuring the recycling of the phase change medium and thus maintaining the continuous operation of the heat spreader. Uniform heat dissipation: The capillary structure 3 helps distribute the phase change medium throughout the heat spreader, allowing heat to be transferred more evenly from the heat source to the entire heat dissipation surface, improving heat dissipation efficiency. Enhanced heat transfer performance: A well-designed capillary structure 3 can increase the contact area between the liquid and vapor, accelerating the phase change process (i.e., the rate of liquid evaporation and vapor condensation), thereby improving the overall heat transfer performance of the heat spreader. Adaptability to different installation angles: Since capillary force is not affected by gravity, even if the heat spreader is not installed horizontally, the capillary structure 3 can still ensure effective liquid reflux, enhancing the application flexibility of the heat spreader. Stability: The presence of the capillary structure 3 also increases the stability of the system, preventing potential dry-out phenomena (i.e., insufficient liquid for evaporation in the evaporation zone), ensuring the long-term stable operation of the heat spreader.
[0077] like Figure 1 As shown in the above embodiment, optionally, at least one of the plurality of columnar structures 21 has a columnar capillary structure 31 inside or outside.
[0078] like Figure 2 As shown, at least one columnar structure 21 is a first columnar structure 211, which is a hollow column with a columnar capillary structure 31 inside. In this case, the columnar capillary structure 31 can shorten the circulation path of the phase change medium, thereby improving the efficiency of the phase change heat cycle in the heat exchanger 101.
[0079] Of course, it should be understood that at least one columnar structure 21 may also be provided with a hollow columnar capillary structure 31 on its exterior, which can also achieve the effect of shortening the circulation path of the phase change medium and improving the efficiency of the phase change heat cycle in the heat exchanger 101.
[0080] Furthermore, when the capillary structure 3 includes only the columnar capillary structure 31, the two ends of the columnar capillary structure 31 are respectively connected to the inner wall surface of the shell 1.
[0081] It should be understood that at this time, the two ends of the columnar capillary structure 31 are respectively set to the first surface S1 and the second surface S2. The columnar capillary structure 31 guides the liquid phase change medium at the end corresponding to the second surface S2 to the end corresponding to the first surface S1 through capillary action, realizing the reflux of the phase change medium.
[0082] Furthermore, when the capillary structure 3 includes a wall-mounted capillary structure 32 and a columnar capillary structure 31, the wall-mounted capillary structure 32 is attached to the inner wall surface of the shell 1, one end of the columnar capillary structure 31 is connected to the wall-mounted capillary structure 32 or the inner wall surface, and the other end of the columnar capillary structure 31 is connected to the wall-mounted capillary structure 32 or the inner wall surface.
[0083] In other words, the columnar capillary structure 31 can be directly connected to the wall-mounted capillary structure 32 or directly connected to the inner wall surface of the shell 1, which is not a limitation.
[0084] For example, the columnar structure 21 can have various types. One type of columnar structure 21 has its two ends connected to the first housing 11 and the second housing 12 described later, respectively, which can reinforce the two opposing parts of the inner wall surface, ensuring the structural stability of the housing 1. Another type of columnar structure 21 has its two ends connected to the first wall-mounted capillary structure 311 and the second wall-mounted capillary structure 312 described later, respectively, which can reinforce the two opposing parts of the wall-mounted capillary structure 32, ensuring the support stability of the wall-mounted capillary structure 32 and the housing 1.
[0085] like Figure 1As shown in the above embodiment, optionally, the housing 1 includes a first housing 11 and a second housing 12, the first housing 11 and the second housing 12 are welded together and form a heat dissipation cavity 101.
[0086] Specifically, the wall-mounted capillary structure 32 includes a first wall-mounted capillary structure 311 and a second wall-mounted capillary structure 312. The first wall-mounted capillary structure 311 and the second wall-mounted capillary structure 312 are respectively disposed corresponding to the first housing 11 and the second housing 12. The first surface S1 is located in the first housing 11 and the second surface S2 is located in the second housing 12.
[0087] In the above embodiments, optionally, the wall thickness of the first housing 11 is greater than or equal to the wall thickness of the second housing 12.
[0088] For example, the wall thickness of the first housing 11 is greater than the wall thickness of the second housing 12. For instance, the first housing 11 focuses on the reliability of the welded structure and its wall thickness is designed to be 1.2-1.5 mm, while the second housing 12 faces the heat sink 5 and its wall thickness is designed to be 0.8-1.2 mm.
[0089] In this way, the structural reliability of the welding between the housing 1 and the semiconductor element 4 can be ensured. When the wall thickness of the first housing 11 is greater than the wall thickness of the second housing 12, the thermal resistance can be reduced by thinning the wall thickness of the second housing 12, thus ensuring the heat dissipation performance of the housing 1 at the second surface S2, and taking into account both the heat dissipation performance requirements of the heat spreader and the structural strength requirements.
[0090] Optionally, the heat exchange chamber 101 is evacuated; or, the heat exchange chamber 101 is filled with a reducing gas.
[0091] In this way, when welding the heat spreader to the semiconductor element 4, the heat spreader can be protected from damage at high welding temperatures caused by the phase change medium in the heat spreader cavity 101 (the high temperature of reflow soldering is usually maintained at 250-300℃. When the phase change medium is placed in the heat spreader cavity 101, it is based on the principle of vacuum phase change heat transfer. When the temperature is >180℃, there is a risk of high temperature bulging and bursting).
[0092] Optionally, in the above embodiments, the heat spreader is made of copper alloy.
[0093] It should be understood that traditional vapor chambers are typically made of oxygen-free copper. The vapor chamber itself (which usually includes a shell 1, capillary structure 3, and support structure 2) is typically manufactured using molecular diffusion welding. This molecular diffusion welding process (e.g., 860℃ high temperature, 20T pressure) causes the oxygen-free copper to become fully annealed copper. Cold-worked metals usually contain a large number of dislocations. High dislocation density increases the material's strength, but during annealing, recovery and recrystallization occur, leading to a reduction in dislocations and grain growth. This increases ductility but reduces structural strength and yield strength. During long-term service, the thermal cycling environment causes the vapor chamber's pressure on the thermal grease 7 to gradually decrease, leading to migration of the thermal grease 7 and the creation of voids, resulting in increased thermal resistance.
[0094] In this optional solution, the heat spreader uses alloy copper (such as phosphor bronze C51000, C52100, etc.) to replace oxygen-free copper material, so that the heat spreader can maintain a certain yield strength (e.g., greater than 70 MPa) after molecular diffusion welding and annealing deoxidation processes, and meet the screw fastening force of greater than or equal to 3 N·m without plastic deformation, ensuring reliability during long-term service.
[0095] The manufacturing process of a vapor chamber is illustrated below: The vapor chamber is entirely made of copper, after the initial processes are completed. The capillary structure 3 and the subsequent phase change medium filling amount of the vapor chamber are designed according to preset loss values. After the first shell 11 and the second shell 12 of the vapor chamber are stamped, copper powder or a copper powder-copper mesh structure (including the capillary structure 3, specifically including wall-mounted capillary structures 32 and columnar capillary structures 31) are filled, and a capillary structure is formed after sintering. Columnar structures 21 (e.g., second columnar structures 212, used to ensure the vapor chamber's strength does not deform) that are not correspondingly configured with columnar capillary structures 31 can also be placed in the gaps before molecular diffusion welding between the upper and lower shells and supporting copper columns. Since the molecular diffusion welding production conditions are around 680℃, the copper product is transformed into a fully annealed state.
[0096] After molecular diffusion welding, the vapor chamber plate undergoes overall annealing and oxidation removal, further reducing its hardness. A liquid injection pipe 8 can be used to evacuate the inside of the vapor chamber plate, creating a vacuum in the vapor chamber 101. Alternatively, a reducing gas can be injected into the vapor chamber plate through the liquid injection pipe 8, followed by sealing. This prevents damage to the vapor chamber plate at the high welding temperatures caused by the presence of a phase change medium in the vapor chamber 101 during subsequent welding of the first surface S1 of the vapor chamber plate to the semiconductor element 4.
[0097] like Figure 4 As shown, another embodiment of this disclosure provides a power device, which includes a semiconductor element 4 and a heat spreader as described in the above embodiment, wherein the semiconductor element 4 is welded to the first surface S1 of the heat spreader.
[0098] As described above, when welding semiconductor components to a heat spreader, a tooling is needed to flatten the heat spreader. That is, by applying pressure, the concave arc surface formed by bending the heat spreader as a whole is pressed into a flat surface, so that the semiconductor component 4 and the first surface S1 of the housing 1 can achieve a good contact surface during welding.
[0099] In this way, the degree of warping and arching of the heat spreader towards the semiconductor element 4 after the first surface S1 of the heat spreader is welded to the semiconductor element 4 can be reduced to a certain extent. This is beneficial to ensuring the heat dissipation performance of the final power device (the power device includes the heat spreader and the semiconductor element 4). Furthermore, when the heat spreader of the subsequent power device is connected to other heat dissipation structures such as the heat sink 5, a more complete contact surface can be obtained between the second surface S2 and the heat sink 5, ensuring the heat dissipation performance of the power device.
[0100] Furthermore, after the semiconductor element 4 is welded to the heat spreader, the second surface S2 of the heat spreader, which is away from the first surface S1, is a convex arc surface that protrudes away from the semiconductor element 4; the second surface S2 is used to connect with the heat sink 5.
[0101] In this way, when the power module is made from the power device and then connected to the heat sink 5, that is, when the heat spreader is connected to the heat sink 5, the second surface S2 and the heat sink 5 can achieve a relatively complete contact surface. The convex arc surface is conducive to spreading the thermal grease 7, thermal adhesive, thermal gel and other materials applied between the heat spreader and the heat sink 5, so as to ensure the heat transfer performance between the heat sink 5 and the power module.
[0102] Another embodiment of this disclosure provides a power module made of the power device described in the above embodiments, wherein a phase change medium is provided in the heat dissipation cavity 101 of the power device.
[0103] Specifically, based on the power device of the above embodiment, a phase change medium is injected into the heat exchange chamber 101 through the liquid injection tube 8, and then sealed to prepare the power module of this embodiment.
[0104] like Figure 5 As shown, another embodiment of this disclosure provides an electrical device including a heat sink 5 and a power module as described in the above embodiment, wherein the second surface S2 of the heat spreader of the power device of the power module is connected to the heat sink 5.
[0105] Optionally, the heat spreader and the heat sink 5 are connected by fasteners 6, and thermal grease 7, thermal adhesive or thermal gel is applied between the second side S2 and the heat sink 5.
[0106] At this time, a clamping force is applied between the heat spreader plate and the heat sink 5 by means of fastener 6. Fastener 6 is usually set at the edge of the heat spreader plate in the first direction X and the edge in the second direction Y. In this way, during the process of applying the clamping force by means of fastener 6, the thermal grease 7, thermal adhesive or thermal gel can be spread out by means of the convex arc surface of the second surface S2.
[0107] While the above disclosure is provided, the scope of protection of this disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of this disclosure, and all such changes and modifications will fall within the scope of protection of this disclosure.
Claims
1. A vapor chamber, characterized by, It includes a housing (1) and a support structure (2). The housing (1) encloses a heat dissipation cavity (101). The support structure (2) is located in the heat dissipation cavity (101) and connected to the housing (1). The heat dissipation plate has an arc-shaped structure. The concave arc surface of the arc-shaped structure is located on the first surface (S1) of the housing (1). The first surface (S1) is the surface of the housing (1) used for welding with the semiconductor element (4).
2. The vapor chamber of claim 1, wherein In at least one direction, the concave arc surface is a face-symmetrical structure, and the contour line where its symmetrical plane intersects the concave arc surface is an arc-shaped contour line.
3. The vapor chamber of claim 2, wherein The curvature of the first arc-shaped contour line (L1) and the second arc-shaped contour line are consistent. The first arc-shaped contour line (L1) is the arc-shaped contour line where the plane of symmetry of the concave arc surface in the second direction (Y) intersects with the concave arc surface. The second arc-shaped contour line is the arc-shaped contour line where the plane of symmetry of the concave arc surface in the first direction (X) intersects with the concave arc surface. The second direction (Y) and the first direction (X) are set at an angle.
4. The vapor chamber of claim 3, wherein Before the heat spreader is bent to form the arc-shaped structure, the first surface (S1) is rectangular, and the first direction (X) and the second direction (Y) are respectively set to the long side and the short side of the rectangle before the heat spreader is bent; when the long side of the rectangle before the heat spreader is bent is greater than or equal to 50 mm and less than or equal to 300 mm, the first arc height (H1) of the first arc contour line (L1) is greater than or equal to 0.5 mm and less than or equal to 1.0 mm.
5. The vapor chamber of claim 2, wherein The support structure (2) includes a plurality of columnar structures (21); the plurality of columnar structures (21) are evenly distributed within the heat exchange cavity (101); And / or, in at least one direction, a plurality of the columnar structures (21) are symmetrically distributed on both sides of the symmetry plane of the concave arc surface.
6. The vapor chamber of claim 5, wherein At least one of the plurality of columnar structures (21) has a columnar capillary structure (31) inside or outside.
7. The vapor chamber of claim 6, wherein The heat spreader also includes a capillary structure (3), which is disposed within the heat spreader cavity (101); When the capillary structure (3) includes only the columnar capillary structure (31), the two ends of the columnar capillary structure (31) are respectively connected to the inner wall surface of the shell (1); When the capillary structure (3) includes a wall-mounted capillary structure (32) and a columnar capillary structure (31), the wall-mounted capillary structure (32) is attached to the inner wall surface of the housing (1), one end of the columnar capillary structure (31) is connected to the wall-mounted capillary structure (32) or the inner wall surface, and the other end of the columnar capillary structure (31) is connected to the wall-mounted capillary structure (32) or the inner wall surface.
8. The vapor chamber of any one of claims 1-7, wherein, The housing (1) includes a first housing (11) and a second housing (12), which are welded together to form the heat exchange cavity (101).
9. The vapor chamber of claim 8, wherein The wall thickness of the first housing (11) is greater than or equal to the wall thickness of the second housing (12).
10. The vapor chamber of any one of claims 1-7, wherein, The heat exchange chamber (101) is evacuated; or, the heat exchange chamber (101) is filled with a reducing gas.
11. The vapor chamber of any one of claims 1-7, wherein, The heat spreader is made of copper alloy.
12. A power device, characterized by It includes a semiconductor element (4) and a heat spreader as described in any one of claims 1 to 11, wherein the semiconductor element (4) is welded to a first surface (S1) of the heat spreader.
13. The power device of claim 12, wherein, After the semiconductor element (4) is welded to the heat spreader, the second side (S2) of the heat spreader, which is away from the first side (S1), is a convex arc surface that protrudes away from the semiconductor element (4); the second side (S2) is used to connect with the heat sink (5).
14. A power module, characterized by Made of the power device according to any one of claims 12-13, wherein the heat dissipation cavity (101) of the power device is provided with a phase change medium.
15. An electrical device, characterized by The device includes a heat sink (5) and a power module as described in claim 14, wherein the second side (S2) of the heat sink (5) of the heat exchange plate of the power device of the power module is connected to the heat sink (5).
16. The electrical device of claim 15, wherein, The heat spreader and the heat sink (5) are connected by fasteners (6), and thermal grease (7), thermal adhesive or thermal gel is applied between the second surface (S2) and the heat sink (5).