Heat dissipation member, vapor chamber, and functional module

Abstract

This heat dissipation member is provided with: a base body having a hollow portion sandwiched between a first inner surface and a second inner surface facing each other; a wick positioned in the hollow portion; and a support column positioned from the first inner surface to the second inner surface. The support column includes a first support column positioned in the wick, and a band-shaped gap extending in the circumferential direction of the first support column is positioned between the first support column and the wick.

Description

Heat dissipation member, vapor chamber and functional module

[0001] The present disclosure relates to a heat dissipation member, a vapor chamber, and a functional module.

[0002] Japanese Patent Application Laid-Open No. 2001-339026 discloses a structure in which a flat vapor chamber has supports that support the hollow portion.

[0003] The heat dissipation member according to the present disclosure comprises a base having a hollow portion sandwiched between opposing first and second inner surfaces, a wick located in the hollow portion, and pillars located across the first and second inner surfaces, wherein the pillars include a first pillar located within the wick, and a band-shaped gap extending circumferentially of the first pillar is located between the first pillar and the wick.

[0004] The vapor chamber according to the present disclosure comprises the heat dissipation member described above and a refrigerant located in the hollow portion.

[0005] The functional module according to the present disclosure comprises: a heat-generating functional component; and the vapor chamber in which the functional component is mounted.

[0006] 4 is a perspective view showing a heat dissipation member and a vapor chamber according to a first embodiment of the present disclosure; FIG. 5 is a plan view showing a heat dissipation member and a vapor chamber according to a first embodiment of the present disclosure; FIG. 6 is a diagram illustrating the overall structure of a wick; FIG. 7 is a cross-sectional view showing details of a wick; FIG. 8 is a plan view showing a heat dissipation member and a vapor chamber according to a second embodiment of the present disclosure; FIG. 9 is an enlarged cross-sectional view showing a portion C1 of FIG. 4; FIG. 10 is an enlarged cross-sectional view showing a portion C2 of FIG. 4; FIG. 11 is an enlarged cross-sectional view showing a portion C3 of FIG. 4; FIG. 12 is a longitudinal cross-sectional view showing a portion of a heat dissipation member and a vapor chamber according to a third embodiment of the present disclosure; FIG. 13 is a diagram showing a functional module according to a fourth embodiment of the present disclosure; FIG. 14 is a diagram showing a functional module according to a fifth embodiment of the present disclosure; FIG. 15 is a diagram showing a functional module according to a sixth embodiment of the present disclosure; FIG. 16 is a diagram showing a functional module according to a seventh embodiment of the present disclosure; FIG. 17 is a diagram showing a functional module according to an eighth embodiment of the present disclosure;

[0007] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings. Below, the up and down directions may be indicated when describing each part. However, these directions may be different from the directions when the heat dissipation member 10 and the vapor chamber 1 are in use.

[0008] (Embodiment 1) Figures 1A and 1B are a perspective view and a plan view, respectively, showing a heat dissipation member and a vapor chamber according to embodiment 1 of the present disclosure. Figure 2 is a diagram illustrating the overall structure of the wick 13. Figure 2 is a cross-sectional view taken along line A-A in Figure 1B. The wick 13 is indicated by shading in Figures 1B and 2. Figure 3 is a cross-sectional view showing the details of the wick 13. Hatching indicating a cross section has been omitted in Figure 3.

[0009] The heat dissipation member 10 according to the first embodiment of the present disclosure includes a base 11 having a hollow portion 111 and a wick 13 located in the hollow portion 111. The wick 13 is omitted from FIG. 1A . The vapor chamber 1 according to the first embodiment of the present disclosure includes the heat dissipation member 10 and a refrigerant located in the hollow portion 111. The hollow portion 111 may be sealed and decompressed. The refrigerant is a fluid that undergoes a phase transition between a gas phase and a liquid phase, and examples of the refrigerant that may be used include water, acetone, methanol, and ammonia.

[0010] The base 11 may have a first inner surface 112 exposed to the hollow portion 111 and a second inner surface 113 exposed to the hollow portion 111 and facing the first inner surface 112. The first inner surface 112 is an inner top surface, and a mounting portion 118 on which a heat source is mounted may be located in a part of the upper portion of the base 11. The second inner surface 113 is an inner bottom surface, and the lower portion of the base 11 may be configured to be cooled. The base 11 may be flat, and in such a configuration, the heat dissipation member 10 may be called a heat dissipation plate. The base 11 may have a sidewall 117.

[0011] The material of the base 11 may be a material with high thermal conductivity, for example, a metal such as copper or aluminum, or a ceramic such as silicon nitride, silicon carbide, aluminum nitride, or aluminum oxide. The base 11 may be made of a single material, or may be made of a combination of multiple types of materials, such as a bottom plate portion made of ceramic and a side wall portion and a top plate portion made of metal.

[0012] The base 11 may include a plurality of support columns 115 that support the hollow portion 111. The support columns 115 may be located across the hollow portion 111 from the first inner surface 112 to the second inner surface 113.

[0013] The wick 13 may have a plurality of minute voids G and gaps g (see FIG. 3 ) and may be configured to transport the liquid phase refrigerant by capillary force generated in the minute voids G and gaps g. The wick 13 may be positioned so as to be in contact with the first inner surface 112. The wick 13 may be positioned so as to be spaced apart from the second inner surface 113.

[0014] As shown in FIG. 1B , the hollow portion 111 may include, in a planar perspective, a region 111A where the wick 13 is located and a region 111B where the wick 13 is not located. In FIG. 1B , the regions 111A and 111B are indicated by dashed lines. The absence of the wick 13 in a planar perspective means that the wick 13 is not located between the first inner surface 112 and the second inner surface 113. As shown in FIG. 2 , in the region 111A where the wick 13 is located, a space 111c may be located between the wick 13 and the second inner surface 113. The region 111B and the space 111c may function as a passage through which the gas-phase refrigerant flows. The region 111B may not be a region where the wick 13 is not located, but may be a region where the wick 13 occupies a smaller proportion than the region 111A. For example, a configuration may be adopted in which the wick 13 is located within a range of 1 / 3 of the height of the hollow portion 111 from the first inner surface 112, and the space portion where the wick 13 is not located is larger than the region 111A. Even with this configuration, the region 111B can function as a flow path through which more gas-phase refrigerant flows than the region 111A. Alternatively, there may be no difference in the arrangement of the wick 13 between the regions 111A and 111B. In other words, the wick 13 may be located in the region 111B as well as in the region 111A. In this case, the space portion 111c functions as a flow path through which the gas-phase refrigerant easily flows.

[0015] The second inner surface 113 of the base 11 may have convex portions 113a protruding upward and concave portions 113b deepening downward. The concave portions 113b may be lattice-shaped grooves in a plan view, or stripe-shaped or radial grooves in a plan view.

[0016] As shown in FIG. 3, the wick 13 may be configured such that a plurality of particles 50 are bonded together via a portion of each particle 50. The components of each particle 50 may be a metal such as copper. Bonding between adjacent particles 50 may be achieved by a sintering process to the extent that the plurality of particles 50 do not become densified. The particle diameter of the particles 50 may be 1 μm to 1000 μm, 10 μm to 700 μm, or 20 μm to 500 μm. The particle diameter D50 of the particles 50 may be 20 μm, 100 μm, or 200 μm. The particle diameter refers to the average of the major axis and the minor axis. The particle diameter D50 refers to the median particle diameter of the particle size distribution.

[0017] Each of the plurality of particles 50 may have a first structure. The first structure is a structure in which a plurality of protrusions protrude obliquely radially from an imaginary central axis and are arranged in multiple stages along the imaginary central axis. The first structure can be formed by growing the particles 50 according to a crystal orientation in electroplating. The plurality of protrusions may include a protrusion having a maximum thickness partway from the base to the tip of the protrusion.

[0018] Alternatively, each of the multiple particles 50 may have a second structure. The second structure may have a structure in which multiple protrusions, each having a maximum thickness midway from the base to the tip, protrude in at least four different directions. The four directions may include components of three-dimensional directions. That is, when the four directions are referred to as the first to fourth directions, the four directions may be directions in which the third or fourth direction intersects with a plane along the first and second directions. The second structure can be produced, for example, by first forming multiple fine powder particles by atomization, and then sintering the multiple fine powder particles to a degree that does not cause densification of the fine powder particles. By forming nearly spherical fine powder particles by atomization, and then sintering the multiple fine powder particles together, the surrounding fine powder particles become protrusions having a maximum thickness midway from the base to the tip.

[0019] Alternatively, each of the plurality of particles 50 may be a particle 50 having a third structure. The third structure is a spherical structure. The spherical shape is not limited to a strict sphere or an oblate sphere, but includes a sphere that includes distortions or small jagged edges. The particles 50 having the third structure can be formed, for example, by an atomization method.

[0020] The wick 13 may have a structure in which the entire plurality of particles 50 is fixed by bonding portions of adjacent particles 50 together. Bonding of portions of the particles 50 together may be achieved by spreading the plurality of particles 50 in a space so that portions of the particles 50 are in contact with each other, and then performing a sintering process in this state to an extent that does not promote densification of the plurality of particles 50. When spreading the plurality of particles 50 in a space, a medium such as a resin may not be present around the plurality of particles 50, and the plurality of particles 50 may be spread in the air or a vacuum as powder.

[0021] When particles 50 having the first or second structure are used, a wick 13 can be realized in which a large number of voids G of various sizes are located between the particles 50, and small gaps g are located within each particle 50, as shown in Figure 3. This wick 13 can achieve the function of transporting a liquid-phase refrigerant by the capillary force generated in the voids G and the gaps g. When particles 50 having the third structure are used, the degree of variation in the size of the voids G, the proportion of the voids G, and the amount of the gaps g will differ, but the function of transporting a liquid-phase refrigerant by the capillary force can be similarly achieved.

[0022] The wick 13 may be fixed in the hollow portion 111 so as to contact the first inner surface 112 (see FIG. 2 ). This fixation may be achieved by bonding the first inner surface 112 to a portion of the particles 50. The bonding of the particles 50 to each other in the wick 13 and the bonding of the particles 50 to the first inner surface 112 may be achieved by the same sintering process. That is, by placing a plurality of particles 50 in the hollow portion 111 with the first inner surface 112 facing downward and performing a sintering process to an extent that does not cause the plurality of particles 50 to become densified, the bonding of the plurality of particles 50 and the bonding of the wick 13 to the first inner surface 112 can be achieved.

[0023] In the vapor chamber 1 configured as described above, for example, a heat source is located on the mounting portion 118 on the upper surface of the base 11, and a cooling portion is located on the bottom surface of the base 11. The liquid-phase refrigerant transported near the heat source on the first inner surface 112 by the capillary force of the wick 13 receives heat from the heat source via the first inner surface 112, undergoing a phase transition to a gaseous refrigerant. This phase transition absorbs a large amount of heat from the heat source. The gaseous refrigerant then flows through the void G within the wick 13, the region 111B where the wick 13 is not located, and the layer on the second inner surface 113 side of the region 111A where the wick 13 is located, using these as passages, releasing heat via the second inner surface 113, thereby transitioning to a liquid-phase refrigerant. This phase transition releases a large amount of heat to the cooling portion. By repeating the above cycle, the vapor chamber 1 can transport a large amount of heat from the heat source to the cooling portion.

[0024] (Embodiment 2) Figure 4 is a plan view showing a heat dissipation member and a vapor chamber according to embodiment 2 of the present disclosure. Figures 5A to 5C are enlarged cross-sectional views showing three points C1 to C3 in Figure 4, respectively. The wick 13 is indicated by shading in Figure 4 and Figures 5A to 5C. The heat dissipation member 10A and vapor chamber 1A of embodiment 2 may be similar to embodiment 1 except for the layout of the wick 13 and the support posts 115.

[0025] 4, the plurality of pillars 115 may include a first pillar 115A located within the wick 13. Being located within the wick 13 may be rephrased as being located within the region 111A in which the wick 13 is located.

[0026] 5A , a band-shaped gap G115 extending in the circumferential direction of the first support 115A may be located between the wick 13 and the first support 115A. The band-shaped gap G115 may be located from the upper end to the lower end of the support 115, or may be located in a partial range in the up-down direction. The band-shaped gap G115 may be located around the entire circumference of the support 115, or may be located in a partial range in the circumferential direction (e.g., 1 / 3 or more, 2 / 3 or more of the entire circumference).

[0027] The base 11 has a heat source located at the mounting portion 118 on its upper surface, while most of the upper surface other than the mounting portion 118 is separated from the heat source. Therefore, the heat dissipation path from the heat source includes a first path in which heat is rapidly dissipated from directly below the heat source via a phase transition and reflux of the refrigerant. Furthermore, the heat dissipation path from the heat source includes a second path in which heat is first diffused to the surroundings via the upper wall portion of the base 11 and then transferred to the refrigerant via the first support column 115A, where it is rapidly dissipated via a phase transition and reflux of the refrigerant. When the amount of heat from the heat source increases, the rate at which heat is dissipated via the second path increases. This increases the rate at which liquid-phase refrigerant transitions to gas phase at locations away from directly below the heat source, which may result in a corresponding decrease in the amount of liquid-phase refrigerant returned to directly below the heat source. In this case, the amount of liquid refrigerant returned to the area directly below the heat source decreases, reducing the rate at which heat is dissipated through the first path and reducing the heat dissipation characteristics of the vapor chamber 1A. Therefore, by positioning the wick 13 around the first support 115A, with a strip-shaped gap G115 sandwiched between them, the amount of liquid refrigerant that transitions to gas around the support 115 can be adjusted to reduce the rate at which the liquid refrigerant returns to a position close to the area directly below the heat source, even when the heat quantity of the heat source increases. Therefore, good heat dissipation characteristics can be obtained according to the expected heat quantity of the heat source.

[0028] As shown in Fig. 5B, the strip-shaped gap G115 may also be located around the second support 115B located in the region 111B where the wick 13 is not located, or around the support 115 located at the boundary between the regions 111A and 111B. As shown in Fig. 5C, a strip-shaped gap G117 may also be located on the inner surface of the side wall 117 of the base 11. These gaps G115, G117 can similarly achieve the effect achieved by the gap G115 of the first support 115A.

[0029] 4, in a plan view perspective, the hollow portion 111 may have a first passage R1 connected to a region 111A where the wick 13 is located, and a second passage R2 connected to a region 111B where the wick 13 is not located. The widths w1 to w5 of the second passage R2 may vary stepwise along the second passage R2.

[0030] A portion of the refrigerant that has undergone a phase transition to gas phase due to the heat from the heat source flows along the second passage R2. Most of the gaseous refrigerant is cooled at the second inner surface 113 and transitions to liquid phase. If the gaseous refrigerant is cooled and transitions to liquid phase over a wide area of ​​the second inner surface 113, the heat is dissipated widely. On the other hand, if the gaseous refrigerant is cooled and transitions to liquid phase over a narrow area of ​​the second inner surface 113, the heat is dissipated narrowly. When the amount of heat from the heat source increases, the refrigerant that has transitioned to gas phase due to the heat flow flows through the second passage R2 at a high flow rate and high speed. If there is no resistance in the second passage R2, the gaseous refrigerant will remain in gas phase along the flow until it reaches the end of the second passage R2, which may result in an uneven transition to liquid phase at the second inner surface 113. Therefore, by providing the second passage R2 with portions where the passage widths w1 to w5 change stepwise as described above, resistance is applied to the gas phase refrigerant flowing through the second passage R2, and even when the refrigerant flow is strong, the gas phase refrigerant can be cooled and transitioned to a liquid phase over a wide area of ​​the second inner surface 113. Therefore, even when the heat source has a large amount of heat, uneven heat dissipation can be reduced, and the heat can be dissipated widely.

[0031] The multiple support columns 115 may include a second support column 115B (see FIGS. 4 and 5B) located inside the second passage R2. Located inside means located away from the boundary between the second passage R2 and the first passage R1 in a planar perspective view, closer to the second passage R2 than the boundary. Furthermore, the wick 13 may include a strip-shaped wick 13A surrounding the entire periphery of the second support column 115B (see FIG. 5B). With this configuration, the second support column 115B and the strip-shaped wick 13A can provide flow resistance to the second passage R2. Therefore, the above-described effect of resistance can be more effectively achieved.

[0032] (Embodiment 3) Fig. 6 is a longitudinal cross-sectional view showing a portion of a heat dissipation member and a vapor chamber according to Embodiment 3 of the present disclosure. The wick 13 is indicated by hatching in Fig. 6. The heat dissipation member 10B and vapor chamber 1B of Embodiment 3 may be the same as those of Embodiment 1 or 2, except for some components of the wick 13, which will be described below.

[0033] 6, in region 111A, wick 13 is located between first inner surface 112 and intermediate surface 114, while space 111c, where wick 13 is not located except for a portion, may extend between intermediate surface 114 and second inner surface 113. Intermediate surface 114 is a smooth imaginary surface along the boundary between wick 13 and space 111c. Space 111c allows gas-phase refrigerant and concentrated liquid-phase refrigerant to flow easily, contributing to smooth circulation of the refrigerant.

[0034] 6, the wick 13 may have a protruding portion 13a that protrudes from the intermediate surface 114 toward the second inner surface 113 and contacts the second inner surface 113. The protruding portion 13a allows the refrigerant that has transitioned to a liquid phase at the second inner surface 113 to be drawn upward by the capillary force of the wick 13. Thus, the space 111c contributes to smooth circulation of the refrigerant, while enhancing the drawing action of the liquid refrigerant in the region 111A. This reduces the occurrence of dryout, in which the liquid refrigerant is depleted in the wick 13.

[0035] The second inner surface 113 may have a protrusion 113a protruding upward and a recess 113b deepening downward. The recess 113b may be a lattice-shaped groove in a plan view or a striped groove in a plan view. The protrusion 13a of the wick 13 may be configured to contact the protrusion 113a of the second inner surface 113. This configuration improves the ease of assembly of the heat dissipation member 10B during the manufacturing stage. That is, during the manufacturing stage, the base 11 is configured by joining a member on the first inner surface 112 side and a member on the second inner surface 113 side, and it is assumed that the height of the tip of the protrusion 13a matches the recess 113b. In this case, when assembling the member on the first inner surface 112 side and the member on the second inner surface 113 side, the protrusion 13a of the wick 13 and the protrusion 113a of the second inner surface 113 collide, and the particles 50 constituting the protrusion 13a are likely to fall off. On the other hand, by adjusting the height of the tip of the protrusion 13a to match the height of the convex portion 113a, it is possible to reduce the falling off of the particles 50 as described above. The protrusion 13a of the wick 13 may be configured to contact the concave portion 113b of the second inner surface 113. With this configuration, it is possible to draw up a large amount of refrigerant from the concave portion 113b where a large amount of liquid refrigerant flows.

[0036] (Functional Module) FIGS. 7A to 8C are diagrams illustrating functional modules according to Embodiments 4 to 8 of the present disclosure, respectively. Functional modules 400A to 400E according to Embodiments 4 to 8 each include a heat-generating functional component 410A to 410E and the vapor chamber 1A of Embodiment 2 equipped with the functional component 410A to 410E. Specific examples of the functional modules 400A to 400E are described below, but the following structure is merely an example, and various modifications are possible to the detailed structure, etc. Detailed illustration of the internal structure of the vapor chamber 1A is omitted in FIGS. 7A to 8C. The vapor chamber 1A may be replaced with the vapor chamber 1B of Embodiment 3.

[0037] (Functional Module of Fourth Embodiment) The functional module 400A of the fourth embodiment may be a light source module, and the functional component 410A may be a light emitting element such as an LED (Light Emitting Diode) or an LD (Laser Diode). The LD may be configured to output laser light for processing or laser light for illumination.

[0038] The functional component 410A may be mounted on the vapor chamber 1A via a submount 420. The submount 420 is a substrate smaller than the vapor chamber 1A and may be made of ceramics such as silicon nitride, silicon carbide, aluminum nitride, or aluminum oxide. Multiple functional components 410A may be mounted on the mounting portion 118.

[0039] The vapor chamber 1A has a sidewall 430 that surrounds the mounting portion 118 of the base 11, and the mounting portion 118 may be located on the inner bottom surface of a recess 431 surrounded by the sidewall 430. The opening of the recess 431 may be covered by a light-transmitting member 432 such as a lens. The light-transmitting member 432 may be bonded to the sidewall 430 to seal the recess 431. The sidewall 430 has a horizontal through-hole 433, and a conductive member 434 that transmits operating power to the functional component 410A may be bonded to the through-hole 433. A cooling mechanism (not shown) may be located below the base 11.

[0040] According to the functional module 400A of the fourth embodiment, a large amount of heat can be dissipated from the functional component 410A, which is a light-emitting element, via the vapor chamber 1A. Therefore, the functional component 410A, which is a light-emitting element, can stably emit light with high brightness. Furthermore, when the functional module 400A has multiple functional components 410A, which are light-emitting elements, the high heat dissipation properties of the vapor chamber 1A can ensure uniform heat distribution among the multiple functional components 410A, thereby ensuring uniform brightness among the multiple functional components 410A.

[0041] (Functional Module of Embodiment 5) The functional module 400B of Embodiment 5 may be a wireless module that transmits wireless signals via a wireless base station or the like. The functional component 410B may be a signal processing circuit such as a beam forming integrated circuit (BFIC) that transmits wireless signals with directionality via an array antenna. Multiple functional components 410B may be mounted on the mounting unit 118. The functional component 410B, which is a signal processing circuit, may be connected to an antenna substrate 441 such as a phased array antenna module (PAAM) substrate on which an array antenna is mounted. That is, multiple functional components 410B may be mounted on the mounting unit 118, an antenna substrate 441 may be located above the multiple functional components 410B, and multiple antennas 441a (e.g., patch antennas) may be located above the antenna substrate 441.

[0042] The vapor chamber 1A may be located between an antenna substrate 441 and another substrate 443 located below the antenna substrate 441 via a spacer 442. Furthermore, a shield case 444 may be located below the substrate 443. The substrate 443 may have an opening 443a, and a heat dissipation component 445 such as a heat pipe embedded in the shield case 444 may extend inside and outside the shield case 444. The heat dissipation component 445 may contact the vapor chamber 1A from below via the opening 443a, and may conduct heat from the vapor chamber 1A to the outside of the shield case 444.

[0043] According to the functional module 400B of the fifth embodiment, a large amount of heat can be dissipated from the functional component 410B, which is a signal processing circuit, via the vapor chamber 1A. This allows for stable transmission of wireless signals. This contributes to increasing the power of the wireless signals, i.e., increasing the output of wireless radio waves, and reducing the module volume.

[0044] (Functional Module of Embodiment 6) The functional module 400C of Embodiment 6 may be a computer module in which a computing LSI (Large Scale Integration) is used as a functional component 410C. The functional component 410C may be an LSI for AI (Artificial Intelligence) processing, an LSI for cloud processing, an LSI for display calculation, an LSI for calculation mounted on a workstation, or any of a variety of other LSIs. In addition to the above LSI, the functional component 410C may also include a memory IC (Integrated Circuit) used by the LSI.

[0045] One or more functional components 410C may be mounted on a module substrate 451 such as a PCB (Printed Circuit Board), and the vapor chamber 1A may be incorporated so that it contacts the functional components 410C from the opposite side of the module substrate 451. Here, contact is not limited to direct contact but also includes connection via a material with high thermal conductivity (e.g., a heat transfer sheet, heat transfer grease, etc.) 452. A heat dissipation component 453, such as a heat pipe 453a and a cooling fin 453b connected to the heat pipe 453a, may be connected below the base 11 of the vapor chamber 1A. Furthermore, the functional module 400C may have a cooling device 454, such as a fan, that cools the heat dissipation component 453.

[0046] According to the functional module 400C of embodiment 6, a large amount of heat can be dissipated from the functional components 410C, such as the LSI and memory IC, via the vapor chamber 1A. This allows stable computational processing by the functional components 410C. This allows the functional module 400C to accommodate the high computing power of the LSI, achieving a functional module 400C with high computing power. Furthermore, the vapor chamber 1A can dissipate heat from the functional components 410C, such as the LSI and memory IC, in response to increased heat generation due to miniaturization of wiring within the LSI, high-speed operation, and the like, as well as increased heat generation due to the three-dimensional mounting of the LSI and memory IC.

[0047] (Functional Module of Embodiment 7) The functional module 400D of Embodiment 7 may be a sensor module in which an image sensor is used as the functional component 410D. The vapor chamber 1A may have a convex portion 461 formed by a portion of the base 11 protruding, and the mounting portion 118 may be located on top of the convex portion 461.

[0048] The functional module 400D, which is a sensor module, may have a package 462 that seals the functional component 410D and a light-transmitting member 463 such as a lens. The package 462 may have an opening 464 in a portion thereof, and the vapor chamber 1A and the package 462 may be joined so that the convex portion 461 fits into the opening 464. The package 462 may have built-in wiring for transmitting electrical signals and power, and electrical signals and power may be transmitted between the functional component 410D and the outside of the package 462 via the wiring. A cooling mechanism (not shown) may be located below the vapor chamber 1A.

[0049] According to the functional module 400D of the seventh embodiment, a large amount of heat can be dissipated from the functional component 410D, which is an image sensor, via the vapor chamber 1A. Therefore, a high-performance image sensor that generates a large amount of heat and performs high-speed information processing can be applied as the functional component 410D. This contributes to improving the functionality of the functional module 400D.

[0050] (Functional Module of Embodiment 8) The functional module 400E of Embodiment 8 may be a power module in which a power semiconductor for power control is used as the functional component 410E. The power semiconductor may be a switching element or a diode. The functional module 400E includes multiple vapor chambers 1A and multiple functional components 410E, and the multiple vapor chambers 1A may be mounted on a single insulating plate 471. The insulating plate 471 may be made of ceramics such as silicon nitride, silicon carbide, aluminum nitride, or aluminum oxide. A heat dissipation fin 475 may be attached to the underside of the insulating plate 471 via a metal heat dissipation plate 474. The vapor chamber 1A and the heat dissipation plate 474 may be bonded to the insulating plate 471 via a bonding material 472. The upper wall of the vapor chamber 1A may be a conductive member, and a wiring member 476 may be electrically connected to the upper wall, and the functional component 410E may be electrically connected so that current flows through the wiring member 476 and the upper wall. The periphery of the vapor chamber 1A, the functional component 410E, the insulating plate 471, and the heat sink 474 may be sealed with a molding material 473.

[0051] According to the functional module 400E of the eighth embodiment, a large amount of heat can be dissipated from the functional component 410E, which is a power semiconductor, via the vapor chamber 1A. Therefore, a high-output power semiconductor that generates a large amount of heat can be used as the functional component 410E, and the functional module 400E can be highly integrated and miniaturized.

[0052] The above describes the embodiments of the present disclosure. However, the heat dissipation member, vapor chamber, and functional module of the present disclosure are not limited to the above embodiments. For example, the above embodiments show specific examples of wicks formed by bonding multiple particles, but wicks of various other structures may be used. Furthermore, the above embodiments show a configuration in which the support pillars have a rectangular cross section, but the support pillars may have various cross sections, such as a circular, elliptical, or oval cross section. In addition, the details shown in the embodiments may be modified as appropriate without departing from the spirit of the invention.

[0053] An embodiment of the present disclosure is described below. In one embodiment, (1) a heat dissipation member includes: a base having a hollow portion sandwiched between a first inner surface and a second inner surface facing each other; a wick located in the hollow portion; and struts located across the first inner surface and the second inner surface, wherein the struts include a first strut located within the wick, and a band-shaped gap extending in a circumferential direction of the first strut is located between the first strut and the wick.

[0054] (2) In the heat dissipation member of (1) above, when the imaginary intermediate surface located between the first inner surface and the second inner surface is called the intermediate surface, the wick is located between the first inner surface and the intermediate surface, while the wick has a protrusion that protrudes from the intermediate surface toward the second inner surface and contacts the second inner surface.

[0055] (3) In the heat dissipation member of (1) or (2) above, the hollow portion has, in plan view, a first passage connecting the areas where the wick is located and a second passage connecting the areas where the wick is not located, and the width of the second passage in plan view changes in a stepped manner along the second passage.

[0056] (4) In any one of the heat dissipation members (1) to (3) above, the hollow portion has, in a planar perspective view, a first passage connecting the areas where the wick is located and a second passage connecting the areas where the wick is not located, the support includes a second support located inside the second passage, and the wick includes a strip-shaped wick surrounding the entire periphery of the second support.

[0057] In one embodiment, (5) a vapor chamber includes: the heat dissipation member according to any one of (1) to (4) above; and a refrigerant located in the hollow portion.

[0058] In one embodiment, (6) the functional module includes: a heat-generating functional component; and (5) a vapor chamber in which the functional component is mounted.

[0059] The present disclosure can be used for heat dissipation members, vapor chambers, and functional modules.

[0060] DESCRIPTION OF SYMBOLS 1, 1A, 1B Vapor chamber 10, 10A, 10B Heat dissipation member 11 Base 13 Wick 13a Protrusion 13A Strip-shaped wick G Gap g Gap 50 Particles 111A Area where wick is located 111B Area where wick is not located R1 First passage R2 Second passage w1 to w5 Width 111c Space 112 First inner surface 113 Second inner surface 113a Convex portion 113b Concave portion 114 Intermediate surface 115 Support 115A First support 115B Second support 117 Side wall G115, G117 Strip-shaped gap 118 Mounting portion 400A to 400E Functional modules 410A to 410E Functional components

Claims

1. A heat dissipation member comprising: a base having a hollow portion sandwiched between first and second inner surfaces facing each other; a wick located in the hollow portion; and pillars located across the first and second inner surfaces, wherein the pillars include a first pillar located within the wick, and a band-shaped gap extending circumferentially of the first pillar is located between the first pillar and the wick.

2. A heat dissipation member as described in claim 1, wherein, when an imaginary intermediate surface located between the first inner surface and the second inner surface is called an intermediate surface, the wick is located between the first inner surface and the intermediate surface, while the wick has a protruding portion that protrudes from the intermediate surface toward the second inner surface and contacts the second inner surface.

3. A heat dissipation member as described in claim 1 or claim 2, wherein the hollow portion has, in plan view, a first passage connecting the areas where the wick is located and a second passage connecting the areas where the wick is not located, and the width of the second passage in plan view changes in a stepped manner along the second passage.

4. A heat dissipation member as described in any one of claims 1 to 3, wherein the hollow portion has, in a planar perspective view, a first passage connecting the areas where the wick is located and a second passage connecting the areas where the wick is not located, the support includes a second support located inside the second passage, and the wick includes a strip-shaped wick surrounding the entire periphery of the second support.

5. A vapor chamber comprising: a heat dissipation member according to any one of claims 1 to 4; and a refrigerant located in the hollow portion.

6. A functional module comprising: a heat-generating functional component; and the vapor chamber according to claim 5, in which the functional component is mounted.

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