WO2021047225A1 - 散热结构和散热系统 - Google Patents

散热结构和散热系统 Download PDF

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Publication number
WO2021047225A1
WO2021047225A1 PCT/CN2020/095375 CN2020095375W WO2021047225A1 WO 2021047225 A1 WO2021047225 A1 WO 2021047225A1 CN 2020095375 W CN2020095375 W CN 2020095375W WO 2021047225 A1 WO2021047225 A1 WO 2021047225A1
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Prior art keywords
heat dissipation
heat
thermally conductive
cavity
channel
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PCT/CN2020/095375
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English (en)
French (fr)
Inventor
项晓东
权泰
沈美
郭跃进
张国飙
安丰伟
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南方科技大学
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Priority to US17/775,757 priority Critical patent/US20220392827A1/en
Publication of WO2021047225A1 publication Critical patent/WO2021047225A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
    • H01L23/367—Cooling facilitated by shape of device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/42—Fillings or auxiliary members in containers or encapsulations selected or arranged to facilitate heating or cooling
    • H01L23/427—Cooling by change of state, e.g. use of heat pipes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
    • H01L23/367—Cooling facilitated by shape of device
    • H01L23/3672—Foil-like cooling fins or heat sinks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L23/00—Details of semiconductor or other solid state devices
    • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
    • H01L23/36—Selection of materials, or shaping, to facilitate cooling or heating, e.g. heatsinks
    • H01L23/373—Cooling facilitated by selection of materials for the device or materials for thermal expansion adaptation, e.g. carbon
    • H01L23/3731—Ceramic materials or glass

Definitions

  • This application relates to the technical field of heat dissipation of semiconductor devices and chips, for example, to a heat dissipation structure and a heat dissipation system.
  • the third-generation semiconductor materials and devices have gradually become the "core" that supports a new generation of information technology, energy saving, emission reduction, and intelligent manufacturing.
  • the third-generation semiconductor materials and devices are characterized by small area and high power. This leads to the problems of more heat generation and more difficult heat dissipation. Therefore, high power density limits the development and application of third-generation semiconductor devices and chips.
  • the heating power density ie, Joule heat per unit area
  • the GaN half-bridge circuit can reach 6400W/cm 2 , which is close to the heat of the sun’s surface density.
  • Part of a graphics processor (Graphics Processing Unit, GPU) has nearly 300W heating power 815mm 2 in size, the heating power density portion of the graphics processor of 37W / cm 2.
  • the central processing unit (CPU) has a maximum heating power consumption of 165W on a chip with a size of 600mm 2 , and the heating power density of the central processing unit is 27.5W/cm 2 .
  • the highest heat-resistant junction temperature of the third-generation semiconductor devices and chips is about 90°C, and can reach about 105°C under special circumstances. If there is no efficient heat dissipation system, the working environment temperature of the device and chip can exceed the highest heat-resistant junction of the device and chip. Temperature, that is, devices and chips will work in an unstable state, resulting in thermal runaway damage.
  • the present application provides a heat dissipation structure and a heat dissipation system to improve heat dissipation efficiency and avoid thermal runaway damage of devices and chips.
  • the embodiment of the present application proposes a heat dissipation structure, and the heat dissipation structure includes:
  • the heat dissipation fins are arranged on at least one side of the heat dissipation channel; the heat dissipation fins located on the same side of the heat dissipation channel are arranged along the extending direction of the heat dissipation channel;
  • the heat dissipation channel and the heat dissipation fin are both formed into a cavity structure; the heat dissipation fin includes a first end and a second end that are opposed to each other, the first end is a closed end, and the second end is an opening The second end communicates with the heat dissipation channel.
  • An embodiment of the present application proposes a heat dissipation system, and the heat dissipation system includes: any of the heat dissipation structures provided in the foregoing embodiments;
  • the heat dissipation system further includes: a heat conduction cavity and a transmission channel, the heat conduction cavity communicates with the heat dissipation structure through the transmission channel, and the connection end of the transmission channel and the heat dissipation structure is higher than the transmission channel and the heat dissipation structure.
  • the connecting end of the heat conducting cavity is not limited to:
  • the heat dissipation system further includes: a heat exchange medium; the liquid heat exchange medium is stored in the heat conduction cavity, and the transmission channel is used to transmit the heat exchange medium heated and vaporized in the heat conduction cavity to the heat dissipation structure, And it is used to transfer the heat exchange medium that causes condensation and liquefaction at the heat dissipation structure to return to the heat conduction cavity.
  • FIG. 1 is a schematic structural diagram of a heat dissipation system provided by an embodiment
  • FIG. 2 is a schematic structural diagram of a heat dissipation structure provided by an embodiment of the present application.
  • FIG. 3 is a schematic structural diagram of another heat dissipation structure provided by an embodiment of the present application.
  • FIG. 4 is a schematic structural diagram of yet another heat dissipation structure provided by an embodiment of the present application.
  • FIG. 5 is a schematic structural diagram of a heat dissipation system provided by an embodiment of the present application.
  • FIG. 6 is a schematic structural diagram of another heat dissipation system provided by an embodiment of the present application.
  • FIG. 7 is a schematic structural diagram of another heat dissipation system provided by an embodiment of the present application.
  • Fig. 8 is a front view of a thermally conductive substrate and a sample to be dissipated according to an embodiment of the present application
  • Fig. 9 is a top view of a thermally conductive substrate and a sample to be dissipated according to an embodiment of the present application.
  • FIG. 10 is a schematic structural diagram of another heat dissipation system provided by an embodiment of the present application.
  • the heat of the chip 300 is conducted to the bottom of the solid heat sink 320 through the heat exchange medium in the connection channel 310; after that, the heat needs to pass through the solid heat sink 320 with a path length of centimeters to the outside Convective medium exchange.
  • the equivalent heat transfer coefficient of any solid material on the centimeter-level heat transfer path can match the heat transfer coefficient of the heat exchange medium (for example, phase change material).
  • the design of the solid heat sink 320 needs to shorten the solid heat exchange path and match the equivalent heat transfer coefficient with the heat dissipation power density of the phase-change heat material.
  • the most cost-saving way is the natural convection of the atmosphere.
  • Its heat dissipation power density is 0.012-0.15W/cm 2 , which is far lower than the upcoming chip heating power density (500-1000W/cm 2 ) .
  • the heat dissipation structure and heat dissipation system provided by the embodiments of the present application are formed into a cavity structure by arranging the heat dissipation channels and the heat dissipation fins, and the heat dissipation area of the heat dissipation structure can be enlarged by 3-6 orders of magnitude on a small-volume heat dissipation structure. Increase the heat dissipation area; that is, use area compensation to match the heating power and the heat dissipation power, and improve the heat dissipation efficiency.
  • the heat dissipation structure 10 includes: a heat dissipation channel 110; a heat dissipation fin 120 arranged on at least one side of the heat dissipation channel 110, and the heat dissipation fins 120 on the same side of the heat dissipation channel 110 are arranged along the extending direction of the heat dissipation channel 110;
  • the channel 110 and the heat dissipation fin 120 are both formed into a cavity structure;
  • the heat dissipation fin 120 includes a first end and a second end that are opposed to each other. The first end is a closed end, the second end is an open end, and the second end is connected to the heat dissipation channel. 110 connected.
  • the heat dissipation structure provided by the embodiments of the present application is formed into a cavity structure by arranging the heat dissipation channel and the heat dissipation fins, and all the surface walls of the cavity structure can be used to realize heat exchange, thereby increasing the heat dissipation area, that is, it can be used in a small
  • the volume of the heat dissipation structure increases the heat dissipation area, thereby improving the heat dissipation efficiency, which is beneficial to avoid thermal runaway damage of devices and chips.
  • the cavity structure of the heat dissipation channel 110 and the heat dissipation fin 120 may allow the heat exchange medium to circulate, thereby realizing the heat exchange process.
  • the first end of the heat dissipation fin 120 is an end of the heat dissipation fin 120 away from the heat dissipation channel 110.
  • the first end of the heat dissipation fin 120 is the top end of the heat dissipation fin 120
  • the second end is the bottom end of the heat dissipation fin 120
  • the second end is provided with an opening. It is connected with the heat dissipation channel 110 to realize the circulation of the heat exchange medium in the heat exchange structure 10.
  • the contact area between the heat exchange medium and the heat dissipation structure 10 can be increased, and the contact area between the heat exchange structure and the atmosphere can be increased, thereby The heat dissipation area can be increased, which is beneficial to improve the heat dissipation efficiency.
  • the heat dissipation structure 10 may also be referred to as a “3D inner hollow heat dissipation fin group”.
  • the heat dissipation surface area of the samples to be dissipated is on the order of square centimeters (cm 2 ).
  • the heat dissipation structure 10 can enlarge the heat dissipation area by 3-6 orders of magnitude in a small volume, that is, the heat dissipation area can reach 1 Square meter (m 2 )-10 square meter (m 2 ) of the order of magnitude.
  • FIG. 2 only exemplarily shows 11 heat dissipation fins 120 located on the same side of the heat dissipation channel 110.
  • the heat dissipation fins 120 may also be located on at least two sides of the heat dissipation channel 110, and the number and shape of the heat dissipation fins 120 can be set according to the actual requirements of the heat dissipation structure 10, which is not limited in the embodiment of the present application. .
  • FIG. 2 only exemplarily shows that the heat dissipation channel 110 extends in the horizontal direction, and the extension direction of the heat dissipation fin 120 is perpendicular to the extension direction of the heat dissipation channel 110, that is, the heat dissipation fin 120 extends in the vertical direction, but not
  • the direction of the extension direction of the heat dissipation fin 120 and the heat dissipation channel 110 may be set, which is not limited in the embodiment of the present application. .
  • the form of the heat dissipation structure 10 will be exemplarily described below in conjunction with FIGS. 2 to 4.
  • the heat dissipation channel 110 extends along the first direction X
  • the heat dissipation fins 120 are arranged along the first direction X
  • the heat dissipation fins 120 extend along the second direction Y, the first direction X Intersect the second direction Y; and the distance between the first end of the same heat dissipation fin 120 and the horizontal plane is greater than or equal to the distance between the second end and the horizontal plane.
  • the heat exchange medium in the heat dissipation channel 110 can be dispersed into the plurality of heat dissipation fins 120; at the same time, the heat exchange medium in the heat dissipation fin 120 can be gathered into the heat dissipation channel 110, which will be combined with other components in the heat dissipation system below. Be explained.
  • the gaseous phase change material carrying heat can be dispersed into the plurality of heat dissipation fins 120 by the heat dissipation channel 110, and then, the heat carried by the gaseous phase change material is dissipating heat.
  • the inner wall and outer wall of the fin 120 finally realize heat exchange with the atmosphere; the heat exchange reduces the temperature of the gaseous phase change material, and can condense and restore the liquid phase change material.
  • the opening end of the heat dissipation fin 120 is lower than or equal to the distance between the second end of the heat dissipation fin 120 and the horizontal plane.
  • the closed end of the fin 120 that is, the open end is horizontal or downward, so that the liquid phase change material can flow back into the heat dissipation channel 110 from the heat dissipation fin 120, thereby realizing the circulation of the heat exchange medium.
  • FIGS. 2 to 4 only exemplarily show that the heat dissipation channel 110 includes two ends, and one end of the heat dissipation channel 110 is open and the other end is closed, but it does not constitute the heat dissipation structure provided by the embodiment of the present application.
  • the heat dissipation channel 110 may also include multiple ends, and at least one of the ends may be set as an open end, or multiple ends may be set as open ends, which can be set according to the actual requirements of the heat dissipation structure 10. Not limited.
  • the first direction X is a horizontal direction
  • the second direction Y is a vertical direction.
  • the first direction X is a vertical direction
  • the angle between the second direction Y and the first direction X can be 90° or 45°
  • the second direction Y can be a horizontal direction or It is the oblique direction of any angle.
  • the angle between the extending direction of the heat dissipation fins 120 and the horizontal direction can also be any angle from 0° to 180°, including 0° and 180°, which can ensure that the heat dissipation fins 120 are arranged in an open manner.
  • the end is horizontal or downward, that is, the liquid heat exchange medium can flow back to the heat dissipation channel 110.
  • FIGS. 2 to 4 only exemplarily show that the heat dissipation fins 120 located on the same side of the heat dissipation channel 110 have the same shape and are cylindrical, and the distance between the first end and the second end
  • the sidewalls are smooth, but they do not constitute a limitation on the heat dissipation structure 10 provided in the embodiment of the present application.
  • the shape of the heat dissipation fins 120 may be conical, truncated, or other three-dimensional shapes.
  • the shapes of the heat dissipation fins 120 may be the same or different; the sidewalls of the heat dissipation fins 120 may be formed to be zigzags.
  • a shape, a broken line, an arc shape, or any other shape can ensure that the heat dissipation structure 10 as a whole has a large heat dissipation area under the premise of a small volume, which is not limited in the embodiment of the present application.
  • an embodiment of the present application also provides a heat dissipation system.
  • the heat dissipation system includes any of the heat dissipation structures provided in the foregoing embodiments. Therefore, the heat dissipation system has the technical effects of the heat dissipation structure in the foregoing embodiments.
  • the similarities can be understood with reference to the above explanation of the heat dissipation structure. I will not repeat them in the following.
  • the heat dissipation system 20 includes a heat dissipation structure 10, and further includes: a heat conduction cavity 210, a transmission channel 220, and a heat exchange medium 230; the heat conduction cavity 210 communicates with heat dissipation through the transmission channel 220
  • the structure 10 is connected, and the connection end of the transmission channel 220 and the heat dissipation structure 10 is higher than the connection end of the transmission channel 220 and the heat conduction cavity 210, the liquid heat exchange medium 230 is stored in the heat conduction cavity 210, and the transmission channel 220 is configured to conduct heat
  • the heat exchange medium 230 heated and vaporized in the cavity 210 is transferred to the heat dissipation structure 10, and is configured to transfer the heat exchange medium 230 condensed and liquefied at the heat dissipation structure 10 back into the heat conduction cavity 210.
  • the sample 300 to be dissipated is attached to at least a part of the side wall of the thermally conductive cavity 210 (in FIGS. 5-7, the sample 300 to be dissipated is attached to the bottom of the thermally conductive cavity 210 as an example for description),
  • the heat of the sample 300 to be dissipated is transferred to the heat exchange medium 230 through the bottom of the heat conducting cavity 210;
  • the heat exchange medium 230 may be a liquid-vapor phase change medium, so that the heat exchange medium 230 is heated and vaporized; in conjunction with FIGS.
  • the gaseous heat exchange medium 230 is transmitted to the heat dissipation structure 10 through the transmission channel 220, and is dispersed by the heat dissipation channel 110 of the heat dissipation structure 10 to the plurality of heat dissipation fins 120; the heat carried by the gaseous heat exchange medium 230 passes through the inner wall of the heat dissipation structure 10 Exchanges heat with the outer wall and the atmosphere, the gaseous heat exchange medium 230 decreases in temperature, and condenses to return to the liquid heat exchange medium 230; the liquid heat exchange medium 230 is collected by a plurality of heat dissipation fins 120 to the heat dissipation channel 110, and passes through the transmission channel 220 flows back into the heat conducting cavity 210.
  • the solid arrow represents the transmission path of the vaporized gaseous heat exchange medium 230
  • the dashed arrow represents the transmission path of the liquefied liquid heat exchange medium 230.
  • FIGS. 5-7 only part of the arrows are exemplarily drawn.
  • the transmission paths of the heat exchange medium 230 in other similar structures can be understood with reference to this, and they are not shown in this document.
  • the sample 300 to be dissipated may be a high-power device or chip.
  • the sidewall of the thermally conductive cavity 210 to which the sample 300 to be dissipated may be attached may be a thermally conductive substrate 212 with higher thermal conductivity.
  • the heat transfer path may include: the heat generated by the sample 300 to be dissipated is transferred to the heat exchange medium 230 through the thermally conductive substrate 212. In the heat dissipation system 20, the heat transmission path is relatively short, and the heat dissipation efficiency is high.
  • the sample 300 to be dissipated may also include a thermally conductive substrate 212; the heating surface of the sample 300 to be dissipated is attached to one side of the thermally conductive substrate 212 to conduct heat. The other side of the base 212 is attached to the bottom of the thermally conductive cavity 210.
  • the heat transfer path may include: the heat generated by the sample 300 to be dissipated is transferred to the heat dissipating medium 230 through the heat conducting substrate 212 and the bottom of the heat conducting cavity 210 in sequence.
  • the heat-conducting cavity 210 can be integrally formed with the same material, and the preparation process is relatively simple and the cost is low.
  • the heat conducting cavity 210 the transmission channel 220, and the heat exchange medium 230 will be exemplarily described with reference to FIGS. 5 to 10 respectively.
  • the thermally conductive cavity 210 includes a thermally conductive substrate 212 and a storage groove 211; the thermally conductive substrate 212 is provided as part of the bottom surface of the thermally conductive cavity 210; the storage groove 211 is provided on the thermally conductive cavity
  • the bottom surface of 210 is located on the side of the thermally conductive substrate 212 away from the heat dissipation structure 10; the surface of the thermally conductive substrate 212 on the side of the cavity facing away from the thermally conductive cavity 210 is used for attaching the sample 300 to be dissipated.
  • the thermally conductive substrate 212 is used to convert a point heat source into an equivalent surface heat source to increase the effective heat exchange area, thereby reducing the thermal conductivity power density.
  • the thermal conductivity of the thermally conductive substrate 212 is greater than or equal to 500 watts per square meter ⁇ degree W/m ⁇ K.
  • the thermally conductive substrate 212 with high thermal conductivity, the heat of the sample 300 to be dissipated can be rapidly diffused along multiple directions of the thermally conductive substrate 212.
  • the arrow in the thermally conductive substrate 212 indicates the direction of heat diffusion from the sample 300 to be dissipated to the thermally conductive substrate 212.
  • the diffusion path of heat also includes other paths from the sample 300 to be dissipated to the thermally conductive substrate 212.
  • the material of the thermally conductive substrate 212 includes diamond.
  • thermal conductivity of common materials can be found in Table 1.
  • thermally conductive substrate 212 by using diamond or other ultra-high solid thermally conductive materials as the material of the thermally conductive substrate 212 with high conductive heat power density, it can replace other materials of the thermally conductive substrate 212 with lower thermal conductivity, thereby improving the thermal conductivity of the thermally conductive substrate 212.
  • heat conduction efficiency the heat inside the sample 300 (such as high power density devices and chips) to be dissipated can be more easily conducted to the surface of the thermally conductive substrate 212 facing the interior of the thermally conductive cavity 210.
  • the ratio between the heating area, the heat conduction area and the heat dissipation area can also be set.
  • the ratio A00 of the area of the heat conducting substrate 212 to the area of the heating surface of the sample 300 to be dissipated satisfies: 5 ⁇ A00 ⁇ 20000; the ratio of the heat dissipation area of the heat dissipation structure 10 to the area of the heat conduction substrate 212 satisfies A01 : A01>B01, where B01 is the ratio of the heating power density of the sample 300 to be dissipated to the heat dissipation power density of the natural convection of the gas.
  • the thermally conductive substrate 212 is in contact with the heating surface of the sample 300 to be dissipated, and a large-area solid thermally conductive substrate 212 material with ultra-high thermal conductivity is used to greatly expand the area of the thermally conductive substrate 212 under the same heating power.
  • the heat can be rapidly diffused along the plane and side of the thermally conductive substrate 212 shown in FIGS. 8 and 9 to turn a point heat source into a surface heat source, thereby greatly reducing the heating power density of the thermally conductive substrate 212, thereby reducing the device And the difficulty of heat dissipation of the chip.
  • the area ratio A00 can be several hundreds to tens of thousands of magnitudes, so that the heating surface can be effectively expanded and the heating power density can be reduced.
  • 500 ⁇ A00 ⁇ 5000, 900 ⁇ A00 ⁇ 8000, 5000 ⁇ A00 ⁇ 80000 or other selectable value ranges can be set according to the actual heat dissipation requirements of the heat dissipation system 20. This embodiment of the application does not make this limited.
  • FIG. 7 only exemplarily shows that the shapes of the thermally conductive substrate 212 and the sample 300 to be dissipated are rectangular.
  • the shape of the thermally conductive substrate 212 may also be a circle, an ellipse, a triangle, other polygons or other shapes; the shape of the sample 300 to be dissipated may be a circle, an ellipse, a triangle, other polygons or other shapes. The embodiment of the application does not limit this.
  • the heat dissipation area of the heat dissipation structure 10 may include the area of the outer wall of the heat dissipation channel and the heat dissipation fins.
  • the heat exchange medium thermally short-circuits the heat conducting base 212 and the heat dissipation structure 10.
  • the power density mismatch can be transformed into power matching, so as to achieve system heat transfer matching.
  • the thickness A11 of the thermally conductive substrate 212 satisfies: 1 ⁇ m ⁇ A11 ⁇ 10cm; along the direction that the inside of the heat dissipation structure 10 points to the outside, the heat dissipation structure
  • the thickness A12 between the inner wall and the outer wall of 10 satisfies: 1 ⁇ m ⁇ A12 ⁇ 10cm.
  • the thickness of the cavity sidewalls of the multiple structures in the heat dissipation system will not be too thin, thereby helping to ensure the overall structural stability of the heat exchange system; on the other hand, the thickness of the cavity sidewalls will not be too thin. Thick, which can ensure higher heat conduction and heat exchange efficiency.
  • 5 ⁇ m ⁇ A11 ⁇ 5cm, 8mm ⁇ A11 ⁇ 5.8cm; 5mm ⁇ A12 ⁇ 7.5cm, 8mm ⁇ A12 ⁇ 5cm or other optional ranges can also be set, which is not limited in the embodiment of the application.
  • the heat exchange medium 230 may include a thermal superconducting phase change material.
  • connecting the heat-conducting area of the heat-conducting substrate 212 and the heat-dissipating area of the heat-dissipating structure 10 requires a heat-exchange medium 230, which transfers heat from the heating surface of the device and chip (equivalent to the heat-conducting surface of the heat-conducting substrate 212) Transfer to the heat dissipation structure 10.
  • the heat exchange medium 230 is attached to the surface of the heat-conducting substrate 212 of the device and chip.
  • the heat exchange power density of the heat exchange medium must be at the same level as the heating power density of the device and chip, and has rapid fluidity, so that heat can be quickly transferred to At the heat dissipation structure 10, a thermal short circuit between the heat conducting substrate 212 and the heat dissipation structure 10 is realized.
  • the gas-phase heat exchange material has fluidity, but the power density is not enough; the liquid-phase heat exchange material has a slightly poor fluidity and the power density is not up to the standard; the solid phase material has the power density up to the standard but does not have fluidity.
  • the heat exchange medium 230 by setting the heat exchange medium 230 to be a thermal superconducting phase change material, it can also be referred to as a "phase change material” or “liquid-vapor phase change material” or “liquid-vapor phase change thermal material” , Can make the heat exchange medium 230 have power density matching at the same time, and have the characteristics of strong fluidity.
  • the heat transfer power density of the liquid-vapor phase heat transfer material can reach 1000 W/cm 2 .
  • heat exchange medium 230 can be selected according to the requirements of the heat dissipation system 20 to ensure that its power density matches the heating power density and has good fluidity.
  • the heat transfer substrate 212 and the heat dissipation structure 10 can be heated. The short-circuit is sufficient, and the embodiment of the present application will not repeat this description and make no limitation.
  • the transmission channel 220 is a rigid channel or a flexible channel.
  • the heat dissipation structure 10 and the thermally conductive substrate 212 of the device and chip are communicated by a transmission channel 220.
  • the effective contact area can be enlarged.
  • the heat transmission path includes: gaseous phase change material ⁇ inner wall of heat dissipation structure ⁇ outer wall of heat dissipation structure ⁇ atmosphere.
  • the contact area can refer to the contact area between the gaseous phase change material and the inner wall of the heat dissipation structure, or the contact area between the outer wall of the heat dissipation structure and the atmosphere.
  • the transmission channel 220 is a rigid channel
  • the shape of the transmission channel 220 is fixed, so that the relative position of the heat conduction cavity 210 and the heat dissipation structure 10 can be fixed, which is beneficial to enhance the overall structural stability of the heat dissipation system 20.
  • the size and size of the transmission channel 220 can be set according to the spatial positional relationship such as the distance and position of the heat dissipation structure 10 and the thermally conductive cavity 210, and the arrangement position relationship of devices and chips.
  • the shape thereby increasing the design flexibility of the heat dissipation system 20.
  • FIGS. 5-7 only exemplarily show that a heat conduction cavity 210 communicates with a heat dissipation structure 10 through a transmission channel 220.
  • a heat conduction cavity 210 may also be provided to communicate with multiple heat dissipation structures 10 through multiple transmission channels 220, respectively, which can be set according to the actual requirements of the heat dissipation system 20, which is not limited in the embodiment of the present application.
  • FIG. 10 exemplarily shows a partially enlarged view of the heat dissipation system 20 in a structure in a bold solid line frame.
  • the heat dissipation system 20 may further include a hydrophobic film layer 251 and a hydrophilic film layer 251.
  • the thermally conductive substrate 212 in is away from the surface of the sample 300 to be dissipated;
  • the water-conducting film layer 253 covers at least one of the surface of the groove structure 211 and the inner surface of the thermally conductive cavity 210 between the thermally conductive substrate 212 and the groove structure 211.
  • a hydrophilic film layer 252 is coated on the heat-dissipating surface of the thermally conductive substrate 212 to make the liquid phase change material easier to adhere to the thermally conductive substrate 212 toward the inside of the thermally conductive cavity 210. on the surface.
  • the surface of the thermally conductive substrate 212 is provided with a storage groove 211, and the heat exchange medium 230 is stored in the storage groove 211.
  • the surface of the storage groove 211 can be easily hydrated, so that the liquid phase change material can be more easily conducted to the device. And the surface of the thermally conductive substrate 212 of the chip.
  • the inner surface of the transmission channel 220 and the heat dissipation structure 10 is hydrophobicized, so that the vapor phase change material does not adhere to the inner surface of the heat dissipation structure 10 and the transmission channel 220 after condensation, and flows quickly along the drainage path. Return to the storage groove 211 of the heat conduction cavity 210, and add the heat exchange cycle again, so that the cycle efficiency can be improved, and the heat exchange efficiency can be improved.
  • the water-conducting membrane layer 253 includes a fiber structure or a core structure.
  • the water-conducting treatment can be realized by capillary action, and the structure is simple.
  • water-conducting membrane structures can also be used, as well as any type of hydrophilic membrane structure and hydrophobic membrane structure, which will not be repeated or limited in the embodiments of the present application.
  • a plurality of samples 300 to be dissipated are attached to the surface of the same thermally conductive substrate 212 away from the thermally conductive cavity 210.
  • a plurality of thermally conductive substrates 212 can be provided, and each sample 300 to be dissipated is attached to a thermally conductive substrate 212 in a one-to-one correspondence.
  • the water-conducting film 253 can also cover adjacent thermally conductive substrates 212. Or adopt other cooperative relationships, which are not limited in the embodiment of the present application.
  • the following describes the heat dissipation process of the heat dissipation system provided in the embodiment of the present application in combination with multiple stages of the heat dissipation process of the heat dissipation system.
  • the essence of solving the heat dissipation of high power density devices and chips is to solve the problem of mismatch between heat dissipation density and heat generation density in multiple heat dissipation stages. Take three stages as an example. In the first stage, heat is conducted from the heating surface of the device or chip to the heat exchange medium through the thermally conductive substrate; in the second stage, the heat exchange medium contacts the inner surface of the heat dissipation structure, and the heat passes through the inner The surface is conducted to the outer surface of the heat dissipation structure; in the third stage, the heat of the outer surface of the heat dissipation structure is convectively exchanged with the atmosphere, thus completing the heat exchange cycle.
  • the equivalent heat dissipation coefficient (h 2 ) of the next stage needs to be set to be equal to or greater than the heat generation/heat transfer/heat conduction of the previous stage Equivalent heat dissipation coefficient (h 1 ): h 2 ⁇ h 1 .
  • phase-change heat power density (q 2 ′′) must be equal to or greater than the heating power density of the previous stage (q 1 ′′): q′′ 2 ⁇ q′′ 1 .
  • the convective heat dissipation power (q 2 ) needs to be equal to or greater than the power (q 1 ) of the previous stage: q 2 ⁇ q 1 .
  • the embodiment of the present application solves the problem of matching the heat exchange power/power density in multiple stages, and completes the design of the heat dissipation system 20.
  • power is the energy/heat generated or exchanged per unit time, the unit is watts (W); power density is the power generated or exchanged per unit area, the unit is watts per square centimeter (W/cm 2 ).
  • the embodiment of the present application proposes a fin-type 3D hollow phase change heat dissipation structure and system.
  • the heat dissipation system 20 includes a heat conduction cavity 210 where a heat conduction substrate is located, a heat dissipation structure 10 composed of fish-fin type 3D hollow heat dissipation fins and a heat dissipation channel, and a transmission channel 220.
  • the thermal superconducting phase change material is stored inside the heat dissipation system 20 as the heat exchange medium 230.
  • thermal conductivity ⁇ 500W/m ⁇ K Use materials with high thermal conductivity such as diamond as the thermally conductive substrate 212, and the heating surfaces of high-power density devices and chips are attached to the bottom of the thermally conductive cavity 210 through the thermally conductive substrate 212 .
  • the thermally conductive substrate 212 is hydrophilized
  • the liquid-vapor phase change material storage groove is located at the bottom of the thermally conductive cavity 210, and the phase change material can be smoothly and fully coated on the hydrophilic surface through capillary action.
  • the height of the heat dissipation structure 10 (ie, the fin-shaped 3D hollow structure) can be higher than the heat-conducting substrate 212, and the heat-conducting cavity 210 can be connected to the heat-dissipating structure 10 through the transmission channel.
  • a flexible transmission channel is added between the device and chip and the 3D hollow heat dissipation structure, which can transfer the increased volume of the heat dissipation system to any place, facilitating the design of the device and the chip itself.
  • the inner wall of the fin-shaped 3D hollow structure is coated with a layer of hydrophobic material to reduce the adhesion of liquid phase change materials.
  • the devices and chips When the heat dissipation system 20 is working, the devices and chips generate heat with high power density, and the heat is transferred to the phase change material through the thermally conductive substrate 212. As the heat accumulates, the temperature of the phase change material rises above the boiling point (phase change temperature), and the liquid-vapor phase change heat dissipation material vaporizes and rises away from the heat dissipation surface. At the same time, the liquid phase change material is stored in a groove on the side and undergoes capillary phenomena and The hydrophilic film quickly adsorbs on the heat dissipation surface of the device and the chip to supplement the vaporized material.
  • the vaporized phase change material passes through the transmission channel (hydrophobic treatment) to reach the fin-shaped 3D hollow structure; the vapor phase change material contacts the inner surface of the 3D hollow heat dissipation fin, and the heat is transferred to the 3D hollow through the phase change material At the radiating fins, the heat of the phase change material itself is reduced, the temperature drops below the boiling point (phase change temperature), and the phase change material becomes liquid again. Due to the hydrophobic treatment of the inner wall of the 3D hollow structure and an oblique downward angle with the horizontal direction, the condensed phase change material passes through the transmission channel, and then reflows and adheres to the surface of the thermally conductive substrate or the phase change material storage groove. The phase change material is attached to the heat dissipation surface of the heat-conducting substrate again through capillary phenomenon and the hydrophilic film layer, completing a cycle of the phase change material.
  • the heat is transferred from the phase change material to the inner radiating fins, the fins are hollow inside, and the surface wall thickness is on the order of 1mm.
  • the heat conduction power density matches the power density of the phase change material, and the heat is transferred to the heat sink through the inner surface wall of the radiating fins
  • the temperature rise of the outer wall of the fin and the heat dissipation wall is controlled at about 1°C.
  • the outer surface of the 3D inner hollow radiating fin is in contact with the air (atmosphere), and the heat is transferred to the atmosphere through heat exchange. Since the heat dissipation area is 3-6 orders of magnitude higher than the chip surface area, the chip heating power matches the atmospheric heat dissipation power, and the chip heating heat is transferred to the atmosphere, completing a complete heat dissipation cycle.
  • the phase change medium can form a thermal short circuit between a local small area high heat power density heat exchange surface and a non-local large area low power density heat exchange surface, that is, the heating surface and the heat dissipation surface are connected by the phase change medium.
  • the thermal circuit can improve the efficiency of heat conduction and heat dissipation; it can also be understood as: the use of phase-change thermal materials as the thermal superconducting link can increase the matching area of the hollow heat dissipation fins and the chip heat dissipation (heat conduction) substrate by 4-5 orders of magnitude , So that the natural convection power of the gas matches the required heat dissipation power.
  • the heat dissipation system 20 can be used for the heat dissipation of high power density devices and integrated circuit chips based on third-generation semiconductors such as silicon carbide SiC or GaN, and solves the problem of heat dissipation that the heating power of high power density devices and integrated circuit chips does not match the heat dissipation power. And has the advantage of low cost.
  • the temperature rise is ⁇ 33°C, that is, when the ambient temperature is 27°C, the chip temperature is ⁇ 60°C, which is much lower than the maximum endurance of the chip
  • the temperature is 85°C, meeting the heat dissipation requirements of future high-power density devices and chip (GaN or SiC) power electronic devices, thereby avoiding thermal runaway damage.

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Abstract

一种散热结构（10）和散热系统（20），该散热结构（10）包括：散热通道（110）；散热翅片（120），设置于散热通道（110）的至少一侧；位于散热通道（110）同一侧的散热翅片（120）沿散热通道（110）的延伸方向排列；散热通道（110）与散热翅片（120）均形成为空腔结构；散热翅片（120）包括相对设置的第一端和第二端，第一端为封闭端，第二端为开口端，第二端与散热通道（110）连通。

Description

散热结构和散热系统
本申请要求在2019年09月10日提交中国专利局、申请号为201910853481.3的中国专利申请的优先权，该申请的全部内容通过引用结合在本申请中。
技术领域
本申请涉及半导体器件及芯片的散热技术领域，例如涉及一种散热结构和散热系统。
背景技术
随着半导体技术的发展，第三代半导体材料和器件逐渐成为支撑新一代信息技术、节能减排和智能制造的“核芯”，但第三代半导体材料和器件的小面积和高功率的特点导致了发热较多以及散热较困难的问题，因此，高功率密度限制了第三代半导体器件和芯片的发展应用。示例性的，当氮化镓GaN半桥电路在10MHz工作频率和400V工作电压时，GaN半桥电路的发热功率密度(即单位面积的焦耳热)可达到6400W/cm 2，接近太阳表面的热密度。部分图形处理器(Graphics Processing Unit，GPU)在815mm 2的尺寸上有近300W的发热功率，部分图形处理器的发热功率密度达37W/cm 2。中央处理器(central processing unit，CPU)在尺寸为600mm 2的芯片上最大发热功耗达到165W，中央处理器的发热功率密度达27.5W/cm 2。据预测，高功率密度器件及芯片的平均功率密度将达到500W/cm 2，热量集中的局部功率密度可超过1000W/cm 2，远远超过现广泛应用的气体对流散热功率密度上限(1.5W/cm 2)以及液体对流散热功率密度上限(120W/cm 2)。
第三代半导体器件和芯片的最高耐热结温为90℃左右，特殊情况可达105℃左右，若无高效的散热系统，器件和芯片的工作环境温度可超过器件和芯片的最高耐热结温，即器件和芯片将工作于非稳定状态下，导致热失控损坏。
发明内容
本申请提供一种散热结构和散热系统，以提高散热效率，避免器件和芯片的热失控损坏。
本申请实施例提出一种散热结构，该散热结构包括：
散热通道；
散热翅片，设置于所述散热通道的至少一侧；位于所述散热通道同一侧的所述散热翅片沿所述散热通道的延伸方向排列；
所述散热通道与所述散热翅片均形成为空腔结构；所述散热翅片包括相对设置的第一端和第二端，所述第一端为封闭端，所述第二端为开口端，所述第二端与所述散热通道连通。
本申请实施例提出一种散热系统，该散热系统包括：上述实施例提供的任一种散热结构；
该散热系统还包括：导热腔体和传输通道，所述导热腔体通过所述传输通道与所述散热结构连通，且所述传输通道与所述散热结构的连接端高于所述传输通道与所述导热腔体的连接端；
该散热系统还包括：换热介质；液态的所述换热介质存储于所述导热腔体内，所述传输通道用于将所述导热腔体内受热汽化的换热介质传输至所述散热结构，以及用于将在所述散热结构处换热导致冷凝液化的换热介质回传至所述导热腔体内。
附图说明
图1是一实施例提供的散热系统的结构示意图；
图2是本申请实施例提供的一种散热结构的结构示意图；
图3是本申请实施例提供的另一种散热结构的结构示意图；
图4是本申请实施例提供的又一种散热结构的结构示意图；
图5是本申请实施例提供的一种散热系统的结构示意图；
图6是本申请实施例提供的另一种散热系统的结构示意图；
图7是本申请实施例提供的又一种散热系统的结构示意图；
图8是本申请实施例提供的导热基底与待散热样品的正视图；
图9是本申请实施例提供的导热基底与待散热样品的俯视图；
图10是本申请实施例提供的又一种散热系统的结构示意图。
具体实施方式
下面结合附图和实施例对本申请进行说明。为了便于描述，附图中仅示出 了与本申请相关的部分而非全部结构。
实施例
随着半导体技术的发展，基于第三代半导体材料和器件的小面积和高功率密度的特点，散热系统的散热效率亟待提高，以避免半导体器件的热失控损失。
热量最终需要与大气交换，才能完成完整的换热过程。参见图1，该芯片散热方案中：芯片300的热量通过连接通道310中的换热介质传导至实心散热片320的底部；其后，热量需经过路径长度为厘米级的实心散热片320与外部对流介质交换。但尚未发现有哪种固体材料在厘米级长度换热路径上的等效换热系数可以匹配换热介质(例如相变材料)的换热系数。基于此，对实心散热片320的设计需将固体换热路径缩短，将等效换热系数与相变换热材料的散热功率密度相匹配。在最终与大气换热阶段，最节省成本的方式是大气自然对流，其散热功率密度为0.012-0.15W/cm 2，远远低于即将达到的芯片发热功率密度(500-1000W/cm 2)。若要完成完整的换热过程，需将散热表面与大气接触面积扩大3-6个数量级，将功率密度不匹配转变为功率匹配，实现系统换热匹配。
本申请实施例提供的散热结构和散热系统，通过设置散热通道和散热翅片均形成为空腔结构，可在小体积的散热结构上将散热结构的散热面积放大3-6个数量级，从而可增大散热面积；即利用面积补偿实现发热功率与散热功率的匹配，提高散热效率。
下面结合本申请实施例中的附图，对本申请实施例中的技术方案进行描述。
参见图2，该散热结构10包括：散热通道110；散热翅片120，设置于散热通道110的至少一侧，位于散热通道110同一侧的散热翅片120沿散热通道110的延伸方向排列；散热通道110与散热翅片120均形成为空腔结构；散热翅片120包括相对设置的第一端和第二端，第一端为封闭端，第二端为开口端，第二端与散热通道110连通。
本申请实施例提供的散热结构，通过设置散热通道和散热翅片均形成为空腔结构，可利用空腔结构的所有表壁实现热交换，从而可增大散热面积，即可以在较小的散热结构的体积上将散热面积增大，从而可提高散热效率，有利于避免器件和芯片的热失控损坏。
在一实施例中，散热通道110和散热翅片120的空腔结构可允许换热介质循环流通，从而实现换热过程。
在一实施例中，散热翅片120的第一端为散热翅片120远离散热通道110的一端。示例性的，以图2中示出的方位为例，散热翅片120的第一端为散热翅片120的顶端，第二端为散热翅片120的底端，第二端设置开口，用于与散 热通道110连通，以实现换热介质在该换热结构10中的流通。
在一实施例中，通过设置散热通道110和散热翅片120均形成为空腔结构，可增大换热介质与散热结构10的接触面积，以及增大换热结构与大气的接触面积，从而可增大散热面积，有利于提高散热效率。
示例性的，该散热结构10还可称为“3D内空散热翅片组”。待散热样品(例如半导体器件和芯片)的散热表面积在平方厘米(cm 2)的量级，该散热结构10可以在较小体积上将散热面积放大3-6个数量级，即散热面积可达到1平方米(m 2)-10平方米(m 2)的量级。
在一实施例中，图2中仅示例性的示出了位于散热通道110的同一侧的11个散热翅片120。在其他实施方式中，散热翅片120还可位于散热通道110的至少两个侧面，且散热翅片120的数量和形态均可根据散热结构10的实际需求设置，本申请实施例对此不作限定。
此外，图2中仅示例性的示出了散热通道110沿水平方向延伸，散热翅片120的延伸方向与散热通道110的延伸方向垂直，即散热翅片120沿竖直方向延伸，但并不构成对本申请实施例提供的散热结构10的限定。在其他实施方式中，还可根据散热结构10的实际需求，结合待散热样品的大小和空间位置关系，设置散热翅片120与散热通道110的延伸方向的指向，本申请实施例对此不作限定。下面结合图2-图4，对散热结构10的形态进行示例性说明。
可选的，参照图2-图4任一图，散热通道110沿第一方向X延伸，散热翅片120沿第一方向X排列，散热翅片120沿第二方向Y延伸，第一方向X与第二方向Y相交；且同一散热翅片120的第一端与水平面之间的距离大于或等于第二端与水平面之间的距离。
如此设置，散热通道110中的换热介质可分散至多个散热翅片120中；同时，散热翅片120中的换热介质可汇聚至散热通道110中，下文中结合散热系统中的其他组成部件进行说明。
示例性的，当换热介质为液-汽相变材料时，携带热量的气态相变材料可由散热通道110分散至多个散热翅片120中，其后，气态相变材料所携带的热量在散热翅片120中通过散热翅片120的内壁和外壁最终实现与大气的热交换；热交换使气态的相变材料的温度降低，可冷凝恢复液态的相变材料。通过设置同一散热翅片120的第一端与水平面之间的距离大于或等于散热翅片120的第二端与水平面之间的距离，即使得散热翅片120的开口端低于或等于散热翅片120的封闭端，即开口端水平或朝下，从而液态的相变材料可由散热翅片120回流至散热通道110中，由此实现换热介质的循环流通。
在一实施例中，图2-图4中仅示例性的示出了散热通道110包括两端，且散热通道110的一端开放，另一端封闭，但并不构成对本申请实施例提供的散热结构10的限定。在其他实施方式中，散热通道110还可包括多端，设置其中的至少一端为开放端即可，也可设置多端均为开放端，可根据散热结构10的实际需求设置，本申请实施例对此不作限定。
下面结合实际空间方位，对第一方向X和第二方向Y的可选方向进行示例性的说明。
可选的，参照图2，第一方向X为水平方向，第二方向Y为竖直方向。
或者，参照图3或图4，第一方向X为竖直方向，第二方向Y与第一方向X的夹角可为90°或45°，即第二方向Y可为水平方向，也可为任意角度的斜角方向。
在其他实施方式中，散热翅片120的延伸方向与水平方向的夹角还可为0°至180°中的任意角度，包括0°和180°，可保证散热翅片120的设置方式为开口端水平或朝下，即液态的换热介质可回流至散热通道110即可。
在一实施例中，图2-图4中仅示例性的示出了位于散热通道110的同一侧的散热翅片120形状均一致，为圆柱形，且第一端和第二端之间的侧壁均平滑，但并不构成对本申请实施例提供的散热结构10的限定。在其他实施方式中，还可设置散热翅片120的形状为圆锥形、圆台形或其他立体形状，散热翅片120的形状可相同，也可不同；散热翅片120的侧壁可形成为曲折状、折线状、弧形状或者形成为任意其他形状，可保证散热结构10整体在小体积的前提下具有较大的散热面积即可，本申请实施例对此不作限定。
在上述实施方式的基础上，本申请实施例还提供了一种散热系统。该散热系统包括上述实施方式提供的任一种散热结构，因此，该散热系统具有上述实施方式中的散热结构所具有的技术效果，相同之处可参照上文中对散热结构的解释说明进行理解，在下文中不再赘述。
示例性的，参照图5-图7任一图，该散热系统20包括散热结构10，还包括：导热腔体210、传输通道220以及换热介质230；导热腔体210通过传输通道220与散热结构10连通，且传输通道220与散热结构10的连接端高于传输通道220与导热腔体210的连接端，液态的换热介质230存储于导热腔体210内，传输通道220设置为将导热腔体210内受热汽化的换热介质230传输至散热结构10，以及设置为将在散热结构10处换热冷凝液化的换热介质230回传至导热腔体210内。
在一实施例中，待散热样品300贴附于导热腔体210的至少部分侧壁(图 5-图7中均以待散热样品300贴附于导热腔体210的底部为例进行说明)，待散热样品300的热量通过导热腔体210的底部传输至换热介质230；换热介质230可为液-汽相变介质，由此，换热介质230受热汽化；结合图2和图5，气态的换热介质230通过传输通道220传输至散热结构10处，并由散热结构10的散热通道110分散至多个散热翅片120；气态的换热介质230所携带的热量通过散热结构10的内壁和外壁与大气进行换热，气态的换热介质230温度降低，冷凝恢复为液态的换热介质230；液态的换热介质230由多个散热翅片120汇集至散热通道110，并通过传输通道220回流至导热腔体210中。
示例性的，图5-图7中，实线箭头代表汽化后的气态的换热介质230的传输路径，虚线箭头代表液化后的液态的换热介质230的传输路径。图5-图7中仅示例性的画出了部分箭头，其他类似结构中的换热介质230的传输路径可参照此理解，本文中未一一示出。
示例性的，实际产品结构中，待散热样品300可为高功率器件或芯片，此时待散热样品300所贴附的导热腔体210的侧壁可设置为导热率较高的导热基底212，以利用导热基底212辅助散热。此时，热量的传输路径可包括：待散热样品300产生的热量通过导热基底212传输至换热介质230。该散热系统20中，热量传输路径相对较短，散热效率较高。
在一实施例中，实际产品结构中，待散热样品300除包括高功率器件和芯片之外，还可包括导热基底212；待散热样品300的发热面贴附于导热基底212的一侧，导热基底212的另一侧贴附于导热腔体210的底部。此时，热量的传输路径可包括：待散热样品300产生的热量依次经过导热基底212和导热腔体210的底部传输至散热介质230。该散热结构20中，导热腔体210可采用同一种材料一体成型，制备工艺较简单，成本较低。
下面结合图5-图10，分别对导热腔体210、传输通道220以及换热介质230进行示例性说明。
可选的，参照图5-图7任一图，导热腔体210包括导热基底212和存储凹槽211；导热基底212设置为导热腔体210的部分底面；存储凹槽211设置于导热腔体210的底面，且位于导热基底212远离散热结构10的一侧；导热基底212背离导热腔体210的空腔一侧的表面用于贴附待散热样品300。
在一实施例中，导热基底212用于将点热源变为等效面热源，以增大有效换热面积，从而降低导热功率密度。
可选的，导热基底212的热传导率大于或等于500瓦/平方米·度W/m·K。
如此设置，通过使用热传导率较高的导热基底212，可使待散热样品300的 热量沿导热基底212的多个方向快速扩散开来，可参照图8和图9。其中，导热基底212中的箭头指向可代表热量由待散热样品300向导热基底212的扩散方向。图8和图9中仅示例性的画出了几个箭头，热量的扩散路径还包括由待散热样品300指向导热基底212的其他路径。
可选的，参照图8，导热基底212的材料包括金刚石。
示例性的，常见材料的导热率可参见表1。
表1 常见材料的热传导率表格
材料 热传导率(W/m·K)
氧化铝(Al 2O 3) 30
碳化硅(SiC) 450
氮化镓(GaN) 110
金刚石 2300
铜 401
铝 237
本实施例中，通过使用金刚石或其他超高固体导热材料作为具有高传导热功率密度的导热基底212的材料，可替代其他热传导率较低的导热基底212的材料，从而可提高导热基底212的热传导效率，待散热样品300(例如高功率密度器件及芯片)内部的热量更容易导出至导热基底212朝向导热腔体210内部的表面。
在此基础上，为实现通过面积补偿达到发热功率与散热功率的匹配，还可对发热面积、导热面积以及散热面积之间的比例进行设置。
示例性的，参照图9，导热基底212的面积与待散热样品300的发热面的面积之比A00满足：5≤A00≤20000；散热结构10的散热面积与导热基底212的面积之比A01满足：A01>B01，其中，B01为待散热样品300的发热功率密度与气体自然对流的散热功率密度的比值。
在一实施例中，导热基底212与待散热样品300的发热面相接触，使用大面积超高热传导率的固体导热基底212的材料，在同样的发热功率下极大地扩大导热基底212的面积，使热量可沿着图8和图9中示出的导热基底212的平面和侧面迅速扩散开来，即可使点热源变成面热源，从而大大降低了导热基底212的发热功率密度，从而降低器件及芯片的散热难度。
示例性的，面积比A00可为几百至上万量级，从而可有效扩大发热面，降低发热功率密度。
示例性的，待散热样品300的宽度可为0.1mm，长度可为0.2mm；导热基底212的长度和宽度均为7mm，其面积比A00＝2450。
在其他实施方式中，还可根据散热系统20的实际散热需求，设置500≤A00≤5000，900≤A00≤8000，5000≤A00≤80000或其他可选取值范围，本申请实施例对此不作限定。
在一实施例中，图7中仅示例性的示出了导热基底212和待散热样品300的形状均为矩形。在其他实施方式中，导热基底212的形状还可为圆形、椭圆形、三角形、其他多边形或其他形状；待散热样品300的形状可为圆形、椭圆形、三角形、其他多边形或其他形状，本申请实施例对此不作限定。
在一实施例中，散热结构10的散热面积可包括散热通道和散热翅片的外壁面积，换热介质将导热基底212与散热结构10热短路，通过设置A01>B01，可通过面积补偿，使散热率与发热率匹配，从而达到较好的散热效果，避免热失控损坏。
示例性的，高功率密度器件及芯片的平均发热功率密度将达到500W/cm 2，热量集中的局部功率密度可超过1000W/cm2，气体自然对流的散热功率密度最大可为1.5W/cm 2，B01可为(500/1.5)＝333.34或(1000/1.5)＝666.6。
在此基础上，通过设置散热表面与大气接触的面积扩大3-6个数量级，可将功率密度不匹配转变为功率匹配，从而实现系统换热匹配。
可选的，参照图8和图10，沿待散热样品300指向导热基底212的方向，导热基底212的厚度A11满足：1μm≤A11＜10cm；沿散热结构10的内部指向外部的方向，散热结构10的内壁与外壁之间的厚度A12满足：1μm≤A12＜10cm。
如此设置，一方面，散热系统中的多个结构的空腔侧壁厚度不会太薄，从而有利于确保换热系统的整体结构稳定性；另一方面，空腔侧壁的厚度不会过厚，从而可确保较高的导热和换热效率。
示例性的，A11＝0.5mm，A12＝1mm。
在其他实施方式中，还可设置5μm≤A11≤5cm，8mm≤A11≤5.8cm；5mm≤A12≤7.5cm，8mm≤A12≤5cm或其他可选范围，本申请实施例对此不作限定。
可选的，换热介质230可包括热超导相变材料。
在一实施例中，连接导热基底212的导热面积与散热结构10的散热面积需要换热介质230，换热介质230将热量从器件及芯片的发热面(等效为导热基底212的导热面)传递至散热结构10处。换热介质230附着在器件及芯片的导热基底212表面，换热介质的换热功率密度必须同器件及芯片的发热功率密度处于同一量级，并且具备快速流动性，如此可将热量迅速传递至散热结构10处，实现导热基底212与散热结构10的热短路。
气相换热材料具有流动性，但功率密度不够；液相换热材料流动性稍差，且功率密度也不达标；固相材料功率密度达标，但不具备流动性。
本实施例中，通过设置换热介质230为热超导相变材料，也可称为“相变材料”或“液-汽相变材料”或“液相-汽相相变换热材料”，可使换热介质230同时具备功率密度匹配，且具备流动性强的特点。
示例性的，液相-汽相相变换热材料的换热功率密度可达1000W/cm 2。
在其他实施方式中，还可根据散热系统20的需求，选用其他类型的换热介质230，确保其功率密度与发热功率密度匹配，且流动性较好，可将导热基底212与散热结构10热短路即可，本申请实施例对此不赘述，也不作限定。
可选的，传输通道220为刚性通道或柔性通道。
在一实施例中，散热结构10和器件及芯片的导热基底212之间由传输通道220连通。如此设计，可实现有效接触面积的放大。其中，热量传输路径包括：气态相变材料→散热结构内壁→散热结构外壁→大气。如此，接触面积可指气态相变材料与散热结构内壁的接触面积，也可指散热结构外壁与大气的接触面积。
示例性的，传输通道220为刚性通道时，传输通道220的形态固定，可使导热腔体210与散热结构10的相对位置固定，有利于增强散热系统20的整体结构稳定性。
示例性的，传输通道220为柔性通道时，可根据散热结构10与导热腔体210的远近、位置等空间位置关系，以及根据器件以及芯片的排布位置关系等需求设置传输通道220的尺寸和形态，从而增加散热系统20的设计灵活性。
在一实施例中，图5-图7中仅示例性的示出了一个导热腔体210通过一条传输通道220与一个散热结构10连通。在其他实施方式中，还可设置一个导热腔体210通过多条传输通道220分别与多个散热结构10同时连通，可根据散热系统20的实际需求设置，本申请实施例对此不作限定。
可选的，图10中以加粗的实线框中的结构示例性的示出了散热系统20的部分局部放大图，参照图10，该散热系统20还可包括疏水膜层251、亲水膜层 252以及导水膜层253；疏水膜层251覆盖传输通道220的内壁、散热通道110的内壁以及散热翅片120的内壁中的至少一处；亲水膜层252至少覆盖导热腔体210中的导热基底212背离待散热样品300的表面；导水膜层253覆盖凹槽结构211的表面以及导热基底212与凹槽结构211之间的导热腔体210的内表面中的至少一处。
在一实施例中，在导热基底212的散热表面涂覆一层亲水膜层252，即做亲水化处理，可使得液态的相变材料更容易附着在导热基底212朝向导热腔体210内部的表面上。导热基底212表面设置有存储凹槽211，存储凹槽211内存储有换热介质230，通过对存储凹槽211的表面做易导水化处理，可使液态相变材料更容易地传导至器件及芯片的导热基底212表面。通过对导热基底212与凹槽结构211之间的导热腔体210的内表面做易导水化处理，可形成由存储凹槽211到导热基底212之间的完整的亲水路径，从而有利于液态相变材料由存储凹槽211向导热基底212表面的传输。
在一实施例中，传输通道220和散热结构10的内表面做疏水化处理，可使得汽态相变材料冷凝之后不在散热结构10和传输通道220的内表面附着，并沿着疏导路径迅速流回导热腔体210的储存凹槽211内，再次加入换热循环，从而可提高循环效率，进而可提高换热效率。
可选的，导水膜层253包括纤维结构或芯结构。
如此设置，可通过毛细作用实现导水化处理，且结构简单。
在其他实施方案中，还可采用其他导水膜层结构，以及采用任何类型的亲水膜层结构和疏水膜层结构，本申请实施例对此不赘述也不作限定。
在一实施例中，在图5-7以及图10中，多个待散热样品300均贴附于同一导热基底212的背离导热腔体210的表面。在其他实施方式中，还可设置多块导热基底212，每个待散热样品300与一块导热基底212一一对应贴附，该结构中，导水膜层253还可覆盖相邻的导热基底212之间的表面；或采用其他配合关系，本申请实施例对此不作限定。
下面结合散热系统的散热过程的多个阶段，对本申请实施例提供的散热系统的散热过程进行说明。
示例性的，解决高功率密度器件及芯片散热的本质是解决多个散热阶段散热密度与发热密度不匹配的问题。以三个阶段为例，第一阶段，热量从器件或芯片的发热面，通过导热基底传导至换热介质；第二阶段，换热介质与散热结构的内表面接触，热量经散热结构的内表面传导至散热结构的外表面；第三阶段，散热结构的外表面热量与大气对流换热，如此完成换热循环。
第一阶段中，对于固体导热，传热路径(导热基底212的厚度)一定时，需设置下一阶段的等效散热系数(h 2)等于或大于上一阶段的发热/传热/导热的等效散热系数(h 1)：h 2≥h 1。
第二阶段中，对于相变换热，若有效接触面积相等，则相变换热功率密度(q 2″)必须等于或大于上一个阶段的发热功率密度(q 1″)：q″ 2≥q″ 1。
第三阶段中，对于对流换热，若有效散热面积不相等，则对流散热功率(q 2)需等于或大于上一阶段的功率(q 1)：q 2≥q 1。
由此，本申请实施例解决了多个阶段的换热功率/功率密度相匹配的难题，将散热系统20设计完整。
需理解功率和功率密度的概念。其中，功率是单位时间内产生或交换的能量/热量，单位是瓦特(W)；功率密度是在单位面积上产生或交换的功率，单位是瓦特每平方厘米(W/cm 2)。
下面结合散热系统20的多个组成结构及相对位置关系，示例性的说明散热系统20的工作过程。
本申请实施例提出一种鱼鳍式3D内空相变散热结构和系统。该散热系统20包括导热基底所在的导热腔体210、鱼鳍式3D内空散热翅片和散热通道组成的散热结构10以及传输通道220。散热系统20内部存储热超导相变材料作为换热介质230。
使用金刚石等具有高热传导率(示例性的，热传导率≥500W/m·K)的材料作为导热基底212，高功率密度器件及芯片的发热面通过导热基底212与导热腔体210的底部贴附。
在一实施例中，导热基底212做亲水化处理，液-汽相变材料存储凹槽位于导热腔体210的底部，相变材料可经过毛细作用顺畅地充分涂敷在亲水表面。
散热结构10(即鱼鳍式3D内空结构)的高度可高于导热基底212，通过传输通道可将导热腔体210与散热结构10连通。在器件及芯片与3D内空散热结构中间，加入一条柔性传输通道，可将散热系统所增加的体积转移至任意处，方便器件及芯片本身的设计。鱼鳍式3D内空结构内壁涂覆一层疏水材料，以减少液态相变材料的附着。
散热系统20工作时，器件及芯片高功率密度发热，热量经过导热基底212传递至相变材料。热量积累，相变材料温度升高，超过沸点(相变温度)，液-汽相变散热材料汽化上升，脱离散热表面；同时，液态相变材料储存在一旁的凹槽内，经过毛细现象及亲水膜迅速吸附在器件及芯片散热表面上，补充汽化走的材料。汽化的相变材料经过传输通道(疏水化处理)到达鱼鳍式3D内空结构处；汽态相变材料与3D内空散热翅片内表壁接触，热量经相变材料传递至3D内空散热翅片处，相变材料自身热量减少，温度下降至沸点(相变温度)以下，相变材料再次相变为液态。由于3D内空结构内壁疏水化处理，并与水平方向成斜向下的夹角，冷凝后的相变材料通过传输通道，而后回流附着至导热基底表面或相变材料存储凹槽内。相变材料经毛细现象和亲水膜层再次附着在导热基底散热表面，完成相变材料的一次循环。
热量由相变材料传递至内空散热翅片，散热翅片内部中空，表壁厚度在1mm量级，热传导功率密度与相变材料功率密度匹配，热量经散热翅片的内表壁传递至散热翅片的外表壁，散热壁的温升控制在1℃左右。3D内空散热翅片的外表壁与空气(大气)接触，经换热将热量传递至大气。由于散热面积高出芯片表面积3-6个量级，使得芯片发热功率与大气散热功率相匹配，将芯片发热热量传递至大气，完成完整的散热循环。
在该散热系统20中，相变介质可将局域小面积高热功率密度换热面与非局域大面积低功率密度换热面形成热短路，即发热面与散热面通过相变介质连通形成热回路，可提高导热及散热效率；也可理解为：采用相变换热材料做热超导链接，可将内空散热翅片与芯片散热(导热)基底匹配的面积提高4-5个数量级，使得气体自然对流的功率与所需散热功率相匹配。
该散热系统20可用于基于碳化硅SiC或GaN等第三代半导体的高功率密度器件及集成电路芯片的散热，解决高功率密度器件及集成电路芯片的发热功率与散热功率不匹配的散热难题，并具备低成本的优势。
示例性的，发热功率密度达到500-1000W/cm 2的高功率密度器件及芯片，温升≤33℃,即在环境温度为27℃情况下，芯片温度≤60℃，远低于芯片最高承受温度85℃，满足未来高功率密度器件及芯片(GaN或SiC)电力电子器件的散热需求，从而可避免热失控损坏。

Claims (13)

  1. 一种散热结构，包括：
    散热通道；
    散热翅片，设置于所述散热通道的至少一侧，位于所述散热通道同一侧的所述散热翅片沿所述散热通道的延伸方向排列；
    所述散热通道与所述散热翅片均形成为空腔结构；所述散热翅片包括相对设置的第一端和第二端，所述第一端为封闭端，所述第二端为开口端，所述第二端与所述散热通道连通。
  2. 根据权利要求1所述的散热结构，其中，所述散热通道沿第一方向延伸，所述散热翅片沿所述第一方向排列，所述散热翅片沿第二方向延伸，所述第一方向与所述第二方向相交；且
    同一所述散热翅片的所述第一端与水平面之间的距离大于或等于同一所述散热翅片的所述第二端与所述水平面之间的距离。
  3. 根据权利要求2所述的散热结构，其中，所述第一方向为水平方向，所述第二方向为竖直方向；或者
    所述第一方向为竖直方向，所述第二方向与所述第一方向的夹角小于或等于90°。
  4. 一种散热系统，包括如权利要求1-3中任一项所述的散热结构；
    还包括：导热腔体和传输通道，所述导热腔体通过所述传输通道与所述散热结构连通，且所述传输通道与所述散热结构的连接端高于所述传输通道与所述导热腔体的连接端；
    还包括：换热介质，液态的所述换热介质存储于所述导热腔体内，所述传输通道设置为将所述导热腔体内受热汽化的换热介质传输至所述散热结构，以及设置为将在所述散热结构处换热导致冷凝液化的换热介质回传至所述导热腔体内。
  5. 根据权利要求4所述的散热系统，其中，所述换热介质包括热超导相变材料。
  6. 根据权利要求4所述的散热系统，其中，所述传输通道为刚性通道或柔性通道。
  7. 根据权利要求4所述的散热系统，其中，所述导热腔体包括导热基底和存储凹槽；
    所述导热基底设置为所述导热腔体的部分底面；
    所述存储凹槽设置于所述导热腔体的底面，且位于所述导热基底远离所述散热结构的一侧；
    所述导热基底背离所述导热腔体的空腔一侧的表面用于贴附待散热样品。
  8. 根据权利要求7所述的散热系统，其中，所述导热基底的热传导率大于或等于500瓦/平方米·度W/m·K。
  9. 根据权利要求8所述的散热系统，其中，所述导热基底的材料包括金刚石。
  10. 根据权利要求7所述的散热系统，其中，所述导热基底的面积与所述待散热样品的发热面的面积之比A00满足：5≤A00≤20000；
    所述散热结构的散热面积与所述导热基底的面积之比A01满足：A01>B01，其中，所述B01为所述待散热样品的发热功率密度与气体自然对流的散热功率密度的比值。
  11. 根据权利要求7所述的散热系统，还包括：疏水膜层、亲水膜层和导水膜层；
    所述疏水膜层覆盖所述传输通道的内壁、所述散热通道的内壁以及散热翅片的内壁中的至少一处；
    所述亲水膜层至少覆盖所述导热腔体中的所述导热基底背离所述待散热样品的表面；
    所述导水膜层覆盖所述凹槽结构的表面以及所述导热基底与所述凹槽结构之间的所述导热腔体的内表面中的至少一处。
  12. 根据权利要求11所述的散热系统，其中，所述导水膜层包括纤维结构或芯结构。
  13. 根据权利要求7所述的散热系统，其中：沿所述待散热样品指向所述导热基底的方向，所述导热基底的厚度A11满足：1微米μm≤A11＜10厘米cm；
    沿所述散热结构的内部指向所述散热结构的外部的方向，所述散热结构的内壁与所述散热结构的外壁之间的厚度A12满足：1μm≤A12＜10cm。
PCT/CN2020/095375 2019-09-10 2020-06-10 散热结构和散热系统 WO2021047225A1 (zh)

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