Heat dissipation member, vapor chamber, and functional module

Abstract

A heat dissipation member according to the present invention is provided with: a substrate having a hollow part and a first surface exposed to the hollow part; and a wick positioned in the hollow part and in contact with the first surface. The wick has a plurality of particles bonded to each other and a plurality of gap parts positioned among the plurality of particles. Each of the plurality of particles has a structure in which a plurality of protrusions protrude obliquely radially from the virtual central axis and are arranged in a plurality of stages along the virtual center axis.

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] Conventionally, there is a vapor chamber in which a wick is located in the hollow portion of a base (see JP 2021-131214 A).

[0003] A heat dissipation member according to one aspect of the present disclosure comprises: a base having a hollow portion and a first surface exposed in the hollow portion; and a wick located in the hollow portion and in contact with the first surface, wherein the wick has a plurality of particles bonded to one another and a plurality of voids located between the plurality of particles, and each of the plurality of particles has 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.

[0004] A heat dissipation member according to one aspect of the present disclosure comprises: a base having a hollow portion and a first surface exposed in the hollow portion; and a wick located in the hollow portion and in contact with the first surface, wherein the wick has a plurality of particles bonded to one another and a plurality of voids located between the plurality of particles, and each of the plurality of particles has a structure in which a plurality of protrusions having maximum girth points protrude in at least four different directions.

[0005] The vapor chamber according to the present disclosure comprises the heat dissipation member described above and a refrigerant located in the hollow portion.

[0006] 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.

[0007] 9A is a perspective view showing a heat dissipation member and a vapor chamber according to a first embodiment of the present disclosure. FIG. 9B is a plan view showing a heat dissipation member and a vapor chamber according to a first embodiment of the present disclosure. FIG. 9C is a view illustrating the overall structure of a wick. FIG. 9D is a view illustrating the microstructure of a wick. FIG. 9E is a view illustrating particles constituting a wick. FIG. 9F is a view illustrating a cross section taken along line B-B of FIG. 4A. FIG. 9G is a view illustrating a cross section of a wick. FIG. 9H is an enlarged view illustrating a cross section of a wick. FIG. 9I is a cross section showing a range from the first surface to the second surface of a hollow portion. FIG. 9I is a view illustrating the orientation of particles in a wick. FIG. 9J is an enlarged view of a portion of one particle constituting a wick. FIG. 9I is a view illustrating a cross section taken along line B1-B1 of FIG. 9A. FIG. 9I is a view illustrating a first example of particles constituting a wick. FIG. 9I is a view illustrating a second example of particles constituting a wick. FIG. 9I is a view illustrating a third example of particles constituting a wick. FIG. 9I is a view illustrating an example of particle distribution in a wick. FIG. 9I is a view illustrating a wick according to a second embodiment. FIG. 9I is a view illustrating a wick according to a third embodiment. FIG. 9I is a graph showing the characteristics of a heat dissipation member having wicks with different particle mixing ratios. FIG. 9I is a view illustrating particles constituting a wick according to a fourth embodiment. FIG. 9I is a view illustrating a cross section of a wick according to a fourth embodiment. FIG. 9I is a plan view showing a support structure of a base according to a fifth embodiment. FIG. 17A is a perspective view showing a heat dissipation member and a vapor chamber of embodiment 6. FIG. 17B is a diagram showing a cross section taken along line C1-C1 of FIG. 17A. FIG. 17C is a perspective view showing a heat dissipation member and a vapor chamber of embodiment 7. FIG. 18A is a diagram showing a cross section taken along line C2-C2 of FIG. 18A. FIG. 18C is a diagram showing a functional module according to embodiment 8 of the present disclosure. FIG. 18D is a diagram showing a functional module according to embodiment 9 of the present disclosure. FIG. 18E is a diagram showing a functional module according to embodiment 10 of the present disclosure. FIG. 18F is a diagram showing a functional module according to embodiment 11 of the present disclosure. FIG. 18G is a diagram showing a functional module according to embodiment 12 of the present disclosure.

[0008] 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.

[0009] (Embodiment 1) Fig. 1A is a perspective view showing a heat dissipation member and a vapor chamber according to embodiment 1 of the present disclosure. Fig. 1B is a plan view showing a heat dissipation member and a vapor chamber according to embodiment 1 of the present disclosure. Fig. 2 is a diagram illustrating the overall structure of the wick 13. Fig. 2 is a cross-sectional view taken along line A-A in Fig. 1B.

[0010] 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. In Figures 1B and 2, the wick 13 is shown shaded. The wick 13 is omitted in Figure 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, ammonia, and the like.

[0011] The base 11 may have a first surface 112 exposed to the hollow portion 111 and a second surface 113 exposed to the hollow portion 111 and facing the first surface 112. The first surface 112 may be an inner top surface, and a heat source may be mounted on the upper portion of the base 11. The second surface 113 may be an inner bottom surface, and a lower portion of the base 11 may be cooled. The base 11 may be flat, and in this case, the heat dissipation member 10 may be called a heat sink.

[0012] 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.

[0013] The base 11 may include a plurality of support columns 115 that support the hollow portion 111. The support columns 115 may be positioned across the hollow portion 111 from the first surface 112 to the second surface 113.

[0014] The wick 13 may have a plurality of minute voids G (see FIG. 3 ) and may be configured to transport the liquid phase refrigerant by capillary force generated in the minute voids G. The wick 13 may be positioned so as to be in contact with the first surface 112. The wick 13 may be positioned so as to be spaced apart from the second surface 113.

[0015] Furthermore, the hollow portion 111 may include, in a planar perspective view, 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 dotted lines. "Where the wick 13 is not located in a planar perspective view" means that the wick 13 is not located between the first surface 112 and the second surface 113. The region 111B may function as a passage through which the gas-phase refrigerant flows.

[0016] In the vapor chamber 1 configured as described above, for example, a heat source is located on a portion of the upper surface of the base 11, and a cooling unit is located on the bottom surface of the base 11. The liquid-phase refrigerant transported to the vicinity of the first surface 112 by the capillary force of the wick 13 undergoes a phase transition to a gas-phase refrigerant by receiving heat transfer from the heat source via the first surface 112. This phase transition absorbs a large amount of heat from the heat source. The gas-phase refrigerant then flows through the void G in the wick 13 and the region 111B where the wick 13 is not located, releasing heat via the second surface 113, thereby transitioning to a liquid-phase refrigerant. This phase transition releases a large amount of heat to the cooling unit. This cycle is repeated, allowing the vapor chamber 1 to transport a large amount of heat from the heat source to the cooling unit.

[0017] <Microstructure of Wick> Fig. 3 is a diagram illustrating the microstructure of the wick 13. Figs. 4A and 4B are diagrams illustrating particles 50 that form the wick 13.

[0018] The wick 13 may be formed by bonding a plurality of particles 50 together. 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. Each particle 50 may be made of a metal such as copper. Bonding between adjacent particles 50 may be achieved by a sintering process to a degree that does not promote densification of the plurality of particles 50. 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.

[0019] The wick 13 may be fixed in the hollow portion 111 so as to contact the first surface 112 (see FIG. 2 ). The wick 13 may be fixed in the hollow portion 111 so as to contact the inner surface of the base 11 and the side surface of the support 115. This fixing may be achieved by bonding the first surface 112 and the side surface to some of the particles 50 that contact these surfaces. This bonding may be achieved by a sintering process that does not cause the multiple particles 50 to become densified.

[0020] The bonding between the particles 50 in the wick 13 and the bonding between the particles 50 and the first 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 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 between the plurality of particles 50 and the bonding between the wick 13 and the first surface 112 can be achieved.

[0021] As shown in Fig. 4, each of the plurality of particles 50 may have a structure in which a plurality of protrusions 51 protrude obliquely radially from an imaginary central axis 53 and are arranged in multiple stages along the imaginary central axis 53. This structure can be formed by growing the particles 50 according to the crystal orientation during electroplating. The plurality of protrusions 51 may include a protrusion 51 having a maximum thickness point T midway from the base to the tip of the protrusion 51.

[0022] The above-described structure of the particles 50 makes it easy to realize a wick 13 that includes many large voids G (see FIG. 3 ) between the particles 50. That is, when a powder of the particles 50 is laid in the hollow portion 111 during the manufacturing process of the wick 13, the above-described structure causes many catches between adjacent particles 50. These catches then create many large voids G between the particles 50. Then, by bonding the particles 50 together through a sintering process, a wick 13 that includes many large voids G can be easily realized.

[0023] Furthermore, there are small gaps g between the multiple small protrusions 51 on the surface of each particle 50. Therefore, the wick 13 contains large gaps G, small gaps G, and even smaller gaps g dispersed throughout. The large gaps G facilitate the movement of the refrigerant, while the small gaps g create a strong capillary force. This structure therefore facilitates the retention and transport of liquid refrigerant and the discharge of gaseous refrigerant, achieving excellent heat dissipation characteristics for the vapor chamber 1. This also achieves heat dissipation characteristics that are particularly suited to situations where a large amount of heat needs to be released with low thermal resistance.

[0024] Furthermore, the plurality of particles 50 may include particles 50 having a structure in which the imaginary central axes 53, 53 are branched into multiple parts along the way. The branches are in an oblique direction, and the oblique direction may be one direction included in the oblique radial direction in which the protrusions 51 protrude.

[0025] Furthermore, by including particles 50 with this structure, when a powder of multiple particles 50 is laid in the hollow portion 111 during the manufacturing stage of the wick 13, more catches can be generated between adjacent multiple particles 50. This catch can then generate larger voids G between the multiple particles 50. Then, by the subsequent sintering process, the multiple particles 50 are bonded together, thereby realizing a wick 13 that includes larger voids G, and achieving good heat dissipation characteristics for the vapor chamber 1.

[0026] Furthermore, each of the plurality of particles 50 may have a cone-shaped portion 55 in which the diameter of the particle 50 gradually increases from one end of the imaginary central axis 53 to the middle. The cone shape may also be called a circular cone shape.

[0027] Furthermore, the cone-shaped portion 55 allows for more catches to be generated between adjacent particles 50 when powder, which is a plurality of particles 50, is laid in the hollow portion 111 during the manufacturing stage of the wick 13. This catch allows for more large voids G to be generated between the particles 50. Then, by the subsequent sintering process, the particles 50 are bonded together, thereby realizing a wick 13 that includes more large voids G, and achieving good heat dissipation characteristics for the vapor chamber 1.

[0028] FIG. 4B shows a cross-sectional view of the particle 50 of FIG. 4A taken along line B-B. When three adjacent protrusions 51 among the multiple protrusions 51 included in one particle 50 are referred to as a first protrusion 51A, a second protrusion 51B, and a third protrusion 51C, the first protrusion 51A may have a maximum thickness point T (see FIG. 4A ) midway from the base to the tip. In this case, as shown in FIG. 4B , the gap g1 between the first protrusion 51A and the second protrusion 51B and the gap g2 between the first protrusion 51A and the third protrusion 51C may be connected closer to the base than the maximum thickness point T. Note that although FIG. 4A shows two maximum thickness points T, the particle 50 may include many protrusions 51 having maximum thickness points.

[0029] The structure of the gaps g1 and g2 creates fine, long gaps g1 and g2, which generate a strong capillary force. Therefore, each particle 50 provides a high retention force for the liquid refrigerant, reducing the occurrence of localized drying of the wick 13. This allows the refrigerant to smoothly transition between the liquid and gas phases throughout the wick 13, contributing to the excellent heat dissipation characteristics of the vapor chamber 1.

[0030] <Details of Void G 1> Fig. 5 is a diagram showing a cross section of the wick 13. Hatching of the cross section of the particles 50 is omitted in Fig. 5. The multiple voids G included in the wick 13 may include a first void G1 having a width wG in the cross section that is larger than the average particle size w50 of the particles 50. The above cross section may be a cross section in any direction.

[0031] In the cross-sectional photograph, the voids G are easily identifiable because their contrast is significantly different from that of the particles 50. Therefore, the size and cross-sectional shape of the voids G can be observed from the cross-sectional photograph. The voids G are almost entirely connected in three-dimensional space. However, by dividing the voids G into blocks in the cross-sectional photograph, the connected voids G can be considered as a collection of multiple voids G. Individual voids G in the cross section are defined as follows: First, in a linearly continuous void region, the maximum width in a direction perpendicular to the linear direction is determined. Next, a point connected to the void region and having a width of 1 / 5 or less of the maximum width is defined as the periphery of one void G. With this definition, an area that includes the void region having the maximum width and is surrounded by the particles 50 and the periphery can be identified as one void G. Then, the width of each void G can be determined.

[0032] Because the particles 50 having multiple protrusions 51 are cut at various locations, it is difficult to distinguish the individual particles 50 in a cross-sectional photograph. However, by observing the surface of the wick 13 with a scanning electron microscope (SEM) (see FIG. 3), the individual particles 50 can be easily distinguished. The particle size of each particle 50 can then be determined from the surface observation. The particle size is the average of the major and minor diameters. Furthermore, by selecting multiple dispersed regions and taking statistics of the particle size of the particles 50 in each region, the average particle size of the multiple particles 50 that make up the wick 13 can be determined.

[0033] According to the above configuration, the first void G1 having a width wG larger than the average particle size w50 of the particles 50 is included, which improves the ease of movement of the liquid or gas phase refrigerant through the first void G1, thereby contributing to the good heat dissipation characteristics of the vapor chamber 1.

[0034] <Details of the Void G 2> As shown in Fig. 5, in the cross section of the wick 13, there may be four or more connection points cn between the first void G1 and another void G. The number of connection points cn may be five or more, or may be six or more. When the boundaries of the individual voids G and the first void G1 are defined using the above definitions, the first void G1 in Fig. 5 is connected to another adjacent void G via six connection points cn.

[0035] According to this configuration, the large first gap G1 is connected to another gap G at four or more connection points cn in the cross section, which further improves the ease of movement of the liquid or gas phase refrigerant through the first gap G1. Having more connection points cn further improves the ease of movement of the refrigerant. This contributes to the excellent heat dissipation characteristics of the vapor chamber 1.

[0036] <Details of the Gaps g Between the Particles 50> Figure 6 is an enlarged view showing the cross section of the wick 13. Hatching of the cross section of the particles 50 is omitted in Figure 6. In the cross section of the wick 13, the width wg of the gaps g between the particles 50 may be smaller than the width wG of the voids G connected to the gaps g. With this configuration, the wick 13 includes voids G of various sizes and gaps g with widths wg even smaller than the width of the voids G. Thus, the voids G improve the ease of refrigerant movement, while the gaps g improve the refrigerant retention force. This reduces the occurrence of localized drying of the wick 13 and facilitates phase transition of the refrigerant and exchange between the liquid and gas phases. This contributes to the excellent heat dissipation characteristics of the vapor chamber 1.

[0037] The multiple particles 50 include adjacent first particles 50A and second particles 50B (see FIG. 6 ), and the gaps gA between the first particles 50A and the gaps gB between the second particles 50B may be in contact. That is, the protrusions 51a, 51a of the first particles 50A, which sandwich the gap gA, and the protrusions 51b, 51b of the second particles 50B, which sandwich the gap gB, are bonded by a sintering process, resulting in a structure in which the gaps gA and gB are in contact with each other. This configuration allows the fine gaps gA and gB to continue for a long period of time, allowing more refrigerant to be held in the gaps g. This further reduces localized drying of the wick 13, contributing to the excellent heat dissipation characteristics of the vapor chamber 1.

[0038] Furthermore, the direction in which the gap gA between the first particles 50A expands may intersect with the direction in which the gap gB between the second particles 50B expands. That is, the gaps gA and gB may be in contact with each other so that an imaginary plane extending along the gap gA between the first particles 50A intersects with an imaginary plane extending along the gap gB between the second particles 50B. With this configuration, the narrow gap G between the first particles 50A and the second particles 50B communicates with the gaps gA and gB, and a strong capillary force can be generated in this portion.

[0039] <Overall Structure of Wick> Fig. 7 is a cross-sectional view showing the range from the first surface 112 to the second surface 113 of the hollow portion 111. In Fig. 7, the cross section of the particle 50 is shown in white, and the void portion G is shown in hatching.

[0040] The cross section of the wick 13 may have a communication passage H that extends from the first surface 112 to the end on the opposite side of the first surface 112 via a gap G. This configuration allows the gas phase refrigerant to be smoothly transported from the first surface 112 side of the wick 13 to the opposite side via the communication passage H, and also allows the liquid phase refrigerant to be smoothly transported from the opposite side of the first surface 112 of the wick 13 to the first surface 112 side due to the capillary force of the small gaps G located around the communication passage H or the gaps g between the particles 50. Therefore, heat is smoothly transported due to the phase transition of the refrigerant, contributing to the good heat dissipation characteristics of the vapor chamber 1.

[0041] In the cross section of the wick 13, the plurality of voids G may include second voids G2 that are in contact with the first surface 112 and have a width wG2 that is greater in the normal direction of the first surface 112 than the average particle size w50 of the particles 50. This configuration increases the amount of liquid-phase refrigerant that is returned to the first surface 112. This increases the amount of phase transition of the refrigerant at the first surface, and increases the amount of heat absorbed via the first surface 112.

[0042] The gaps g between the particles 50 may be adjacent to the region 111B where the wick 13 is not located. In other words, if the region 111B is considered a flow path for the gaseous refrigerant, the gaps g between the particles 50 may be adjacent to the flow path. If the liquid-phase transfer path is adjacent to the flow path for the gaseous refrigerant, localized drying of the liquid-phase transfer path is likely to occur in that area. On the other hand, providing more walls than necessary to separate the two narrows the internal space. However, in this embodiment, the flow path for the gaseous refrigerant is adjacent to minute gaps g that generate strong capillary forces, thereby reducing the occurrence of the localized drying. Therefore, the flow of the gaseous refrigerant and the reflux of the liquid-phase refrigerant counter to the flow are smooth, contributing to the excellent heat dissipation characteristics of the vapor chamber 1.

[0043] As shown in FIGS. 2 and 7 , the hollow portion 111 may have a space 111c between the wick 13 and the second surface 113. Furthermore, the space 111c may have irregularities 111c1 and 111c2 in the direction in which the first surface 112 and the second surface 113 face each other. One of the irregularities 111c1 may be due to the irregular shape of the end surface of the wick 13, and the other irregularity 111c2 may be due to the irregular shape of the second surface 113. The space 111c may have only one of the irregularities 111c1 and 111c2. With this configuration, the irregularities 111c1 and 111c2 create narrow and wide portions in the space 111c. Gas-phase refrigerant flows more easily through the wide portions, and liquid-phase refrigerant flows more easily through the narrow portions. Therefore, in the space 111c, there are areas where the gas phase refrigerant can easily flow and areas where the liquid phase refrigerant can easily flow, and the refrigerant can be smoothly circulated. This contributes to the excellent heat dissipation characteristics of the vapor chamber 1.

[0044] <Particle Orientation> Fig. 8 is a diagram illustrating the orientation of the particles 50 in the wick 13. When viewed from any direction, the vertices 55a of the particles 50 may be oriented in multiple dispersed directions. In Fig. 8, the orientation of the vertices 55a is indicated by dashed arrows.

[0045] The apex 55a refers to the apex of the cone-shaped portion 55, and the direction in which the apex 55a faces refers to the direction along the center line of the cone-shaped portion 55, toward the apex 55a. "Facing in multiple dispersed directions when viewed from one direction" is defined as follows: When an arbitrary rectangular region containing 10 vertical and 10 horizontal particles is selected and four angular ranges are set within the rectangular region, dividing at least 360 degrees into four, the particles 50 located on the surface of the rectangular region include four particles 50 facing in each of the four angular ranges. The "arbitrary rectangular region" can be selected not only on the outer surface of the wick 13 but also inside the wick 13. To select an arbitrary rectangular region within the wick 13, the wick 13 is cut or broken at a target location, and if there are particles 50 in the target location that do not maintain their original shape, the particles 50 are peeled off. By performing this processing, a rectangular region can be set at a target location within the wick 13, and the rectangular region can be observed using an SEM.

[0046] According to the above configuration, the vertices 55a of the particles 50 are oriented in a plurality of dispersed directions, resulting in a plurality of voids G of appropriately dispersed sizes being positioned between the particles 50. This allows for smooth circulation of the refrigerant through the wick 13, contributing to the excellent heat dissipation characteristics of the vapor chamber 1.

[0047] 8, the plurality of particles 50 may include a third particle 50C in which the apex 55a of the particle 50 faces the adjacent gap G. The particle 50 has many gaps g formed between the plurality of protrusions 51 on the side opposite to the apex 55a of the cone-shaped portion 55. Therefore, in a single particle 50, the liquid-phase refrigerant tends to move easily from the apex 55a to the opposite side.

[0048] According to the above configuration, the apex 55a faces the gap G, which facilitates the transfer of liquid-phase refrigerant away from the gap G. When a large amount of gas-phase refrigerant flows into the gap G near the heat source, localized drying is likely to occur near the gap G. However, in particles 50 oriented as described above, the cone-shaped portions 55 function as partition walls, improving the ability to retain liquid-phase refrigerant in the gaps g between particles 50 adjacent to the gap G. Therefore, the flow of gas-phase refrigerant through the gap G and the return flow of liquid-phase refrigerant counter to this flow are smooth, contributing to the excellent heat dissipation characteristics of the vapor chamber 1.

[0049] The plurality of particles 50 may include a fourth particle 50D in which the side opposite to the vertex 55a of the particle 50 faces the adjacent gap G, as shown in FIG.

[0050] With this configuration, when a large amount of gas-phase refrigerant flows into the gap G near the heat source, the wide portion opposite the apex 55a faces the gap G, thereby reducing the amount of gas-phase refrigerant entering the gap G. This reduces interference between the gap G through which the gas-phase refrigerant flows and the area through which the liquid-phase refrigerant returns. This allows for smooth flow of the gas-phase refrigerant and the return of the liquid-phase refrigerant that flows against the flow, contributing to the excellent heat dissipation characteristics of the vapor chamber 1.

[0051] <Details of the Particle> FIG. 9A is an enlarged view of a portion of one particle constituting the wick. FIG. 9B is a view showing a cross section taken along line B1-B1 in FIG. 9A . The particle 50 may have a smoother outer shape compared to the powder in the raw material state. Specifically, each of the particles 50 constituting the wick 13 may have a plurality of valleys 57 located between the plurality of protrusions 51, and 20% or more of the valleys 57 exposed on the surface may be gentle valleys 57a having rounded bottoms. As shown in FIG. 9B , the gentle valleys 57a are valleys having rounded bottoms like U-shaped grooves. The proportion of the gentle valleys 57a among the valleys 57 exposed on the surface may be 50% or more, or may be 80% or more.

[0052] It is difficult to count the proportion of the gentle valley portions 57a for all particles 50 in the wick 13. Therefore, the proportion of the gentle valley portions 57a can be calculated by randomly selecting multiple regions from the photograph obtained by SEM and counting the number of valley portions 57 and gentle valley portions 57a in those regions.

[0053] The formation of the gentle valley portion 57 a can be achieved by controlling the sintering temperature and time in the sintering process for fixing the plurality of particles 50 in the hollow portion 111 .

[0054] The gentle valleys 57a act to increase the ease of movement of the liquid-phase refrigerant. By including the gentle valleys 57a in the surface valleys 57 at the above-mentioned ratio, the transport capacity of the refrigerant held in the wick 13 is increased, and better heat dissipation characteristics of the vapor chamber 1 can be obtained.

[0055] <Particle Shape Variation> Figures 10A to 10C are diagrams showing first to third examples of particles constituting the wick, respectively. The multiple particles 50 constituting the wick 13 may include first-shaped particles 50H1 and second-shaped particles 50H2 and 50H2b, which have different thickness increase rates around the imaginary central axis 53. The thickness increase rate around the imaginary central axis 53 corresponds to the ratio of the maximum value to the minimum value of the width dimension of the particle 50 around the imaginary central axis 53 (more specifically, the width dimension of each branch if the imaginary central axis 53 is branched). However, the above width dimension refers to the width dimension in the range including the protrusion 51, excluding the width dimension in the vicinity of the vertex 55a where the protrusion 51 is not located.

[0056] The first-shaped particle 50H1 has a small rate of increase in thickness about the imaginary central axis 53 (for example, less than 7.5 times, less than 4.5 times, less than 1.5 times, etc.). Specifically, the first-shaped particle 50H1 has small ratios of maximum values ​​wH3, wH6, and wH8 to minimum values ​​wH1 and wH4 among width dimensions wH1 to wH8 about the imaginary central axis 53, as described above. When the imaginary central axis 53 branches midway, the width dimensions about each imaginary central axis 53 may have the above-described ratios. The first-shaped particle 50H1 may also be called a thin first-shaped particle 50H1.

[0057] The second-shaped particles 50H2 and 50H2b have a large rate of increase in thickness about the imaginary central axis 53 (for example, 7.5 times or more, 14 times or more, 20.5 times or more, etc.). Specifically, the second-shaped particles 50H2 and 50H2b have a large ratio of the maximum values ​​wH12 and wH22 to the minimum values ​​wH11 and wH21 of the width dimensions wH11, wH12, wH21, and wH22 about the imaginary central axis 53. The second-shaped particles 50H2 and 50H2b may also be referred to as thick second-shaped particles 50H2 and 50H2b.

[0058] Furthermore, the thick second-shaped particles 50H2 and 50H2b include second-shaped particles 50H2b in which the average diameter of the plurality of protrusions 51 is at least twice as large as the average diameter of the plurality of protrusions 51 in the thin first-shaped particles 50H1. The second-shaped particles 50H2b may also be referred to as coarse second-shaped particles 50H2b.

[0059] The definition of thin particles and thick particles may not be based on the above-mentioned definition 1 based on the "rate of increase in thickness," but may be based on the following definition 2 or 3.

[0060] <<Definition 2>> Definition 2 first introduces specific section lengths L1 to L5 (see FIG. 10) of the imaginary center axis 53. The specific section is a section from the position of the smallest width dimensions wH1, wH4, wH11, and wH21 to the position of the largest width dimensions wH3, wH6, wH8, wH12, and wH22.

[0061] A particle satisfying the following formula (1) is defined as a thin first-shaped particle 50H1: 1≦length of specific section of imaginary central axis 53 / maximum width dimension<3.2 (1)

[0062] Furthermore, particles that satisfy the following formula (2) are defined as thick second shape particles 50H2 and 50H2b: 0.2≦length of specific section of imaginary central axis 53 / maximum width dimension<1 (2)

[0063] The first-shaped particles 50H1 satisfying the above formula (1) have an elongated shape or a shape in which an elongated particle is branched, and tend to have small gaps G between them and surrounding particles 50. The second-shaped particles 50H2 and 50H2b satisfying the above formula (2) have a shape that spreads in the width direction, and tend to have large gaps G between them and surrounding particles 50. When the "specific section length of the imaginary central axis 53 / maximum width dimension" was measured for several particles 50, values ​​such as 2.93 and 1.40 were obtained for the elongated particles 50, and values ​​such as 0.79 and 0.27 were obtained for the particles 50 that spread in the width direction.

[0064] <<Definition 3>> Definition 3 also introduces specific section lengths L1 to L5 (see FIG. 10) of the imaginary center axis 53. The specific sections are sections extending from the positions of the smallest width dimensions wH1, wH4, wH11, and wH21 to the positions of the largest width dimensions wH3, wH6, wH8, wH12, and wH22.

[0065] Then, particles that satisfy the following formula (3) are defined as thin first-shaped particles 50H1: 5.5≦length of specific section of imaginary central axis 53 / minimum width dimension<14 (3)

[0066] Furthermore, particles that satisfy the following formula (4) are defined as thick second shape particles 50H2 and 50H2b: 2≦length of specific section of imaginary central axis 53 / minimum width<5.5 (4)

[0067] The first-shaped particles 50H1 satisfying the above formula (3) have an elongated shape or a shape branched from an elongated shape, and tend to have small gaps G between them and surrounding particles 50. The second-shaped particles 50H2 and 50H2b satisfying the above formula (4) have a shape that spreads in the width direction, and tend to have large gaps G between them and surrounding particles 50. When the "specific section length of the imaginary central axis 53 / final width dimension" was measured for several particles 50, values ​​such as 13.58, 5.35, 5.69, and 2.34 were obtained for particles 50 that spread in the width direction from the elongated particles 50.

[0068] Thin particles and thick particles can be classified in substantially the same manner by any of definitions 1 to 3 using the above-mentioned "rate of increase in thickness," "length of a specific section of the imaginary central axis 53 / maximum width," or "length of a specific section of the imaginary central axis 53 / minimum width."

[0069] The average diameter of the plurality of protrusions 51 in the thin first-shaped particle 50H1 may be a first value (e.g., 5 μm to 12 μm), and the average diameter of the plurality of protrusions 51 in the coarse second-shaped particle 50H2b may be a second value (e.g., 12 μm to 25 μm).

[0070] The particle diameter of the thin first-shaped particle 50H1 may be smaller than the particle diameter of the thick second-shaped particle 50H2, 50H2b because of its narrower width. However, even if the thin first-shaped particle 50H1 has a virtual central axis 53 that branches into multiple axes, the particle diameter may be approximately the same as the particle diameter of the thick second-shaped particle 50H2, 50H2b.

[0071] The powder, which is the raw material for the particles 50, may be produced by electroplating metal crystals grown according to a crystal orientation and then dividing them into particles. The wick 13 may then be formed by fixing multiple powders together through a sintering process. Furthermore, a single powder whose surface has been smoothed by the sintering process may correspond to a single particle 50. When particles 50 are formed in this manner, the thin first-shaped particles 50H1 can be formed from powder divided from the leading end of the grown metal crystals, which has a short growth period. The thick second-shaped particles 50H2 can be formed from powder divided from the middle portion, which has a medium growth period. The coarse second-shaped particles 50H2b can be formed from powder divided from the root of the grown metal crystals, which has a long growth period.

[0072] The plurality of particles 50 having the above-described shape variations can cause variations in the size of the voids in the wick 13. The variation in the size of the voids can increase the retention and transport capacity of the liquid refrigerant by the wick 13, thereby achieving better heat dissipation characteristics of the vapor chamber 1.

[0073] <Particle Distribution> Figure 11 is a diagram showing an example of particle distribution in the wick. Hereinafter, the region where the wick 13 is located is divided into three regions from the first surface 112 to the end opposite the first surface 112, and these regions are referred to as a first region R1, a second region R2, and a third region R3 from the side closest to the first surface 112. The first region R1 and the third region R3 have a height width long enough to accommodate two to three particles 50 on average.

[0074] The particles 50 distributed in the first region R1 may have more thin first-shaped particles 50H1 than thick second-shaped particles 50H2, 50H2b. In the first region R1, the ratio (number of thick second-shaped particles 50H2, 50H2b) / (number of thin first-shaped particles 50H1) may be 1 / 3 or less, 1 / 5 or less, or 1 / 7 or less.

[0075] The particles 50 distributed in the third region R3 may have more thick second-shaped particles 50H2 and 50H2b than thin first-shaped particles 50H1. In the third region R3, the ratio (number of thin first-shaped particles 50H1) / (number of thick second-shaped particles 50H2 and 50H2b) may be 2 / 3 or less, 1 / 2 or less, or 1 / 3 or less.

[0076] The above-mentioned distribution of particles 50 can be achieved by laying the powder in the hollow portion 111 before sintering so that the powder that will become the thin first-shaped particles 50H1 is more in the first region R1 and the powder that will become the thick second-shaped particles 50H2, 50H2b is more in the third region R3, and then performing a sintering process in this state so that the multiple particles 50 are bonded together.

[0077] The distribution of the first shaped particles 50H1 and the second shaped particles 50H2 and 50H2b described above enhances the capillary force of the wick 13 in the first region R1 close to the heat source, while also enhancing the ease of refrigerant movement in the third region R3 away from the heat source. This reduces localized drying of the wick 13 in the first region R1 close to the heat source, and facilitates the smooth delivery of gaseous refrigerant from the third region R3 and the smooth intake of liquid refrigerant. This results in improved heat dissipation characteristics for the vapor chamber 1.

[0078] <Details of Particle Orientation and Details of Junctions Between Particles and First Surface> When the wick 13 is viewed from the first surface 112, the particles 50 constituting the wick 13 may be predominantly composed of particles 50 whose vertices 55a (see FIG. 10) face the first surface 112 (see FIG. 11). Facing the first surface 112 means that when a particle 50 is viewed from the first surface 112, the vertex 55a is visible and not hidden by other portions of the particle 50. Making up a majority of the particles 50 means that the vertex 55a accounts for 40% or more, 50% or more, or 60% or more. When the wick 13 is viewed from the first surface 112, the particles 50 that are visible and not hidden by other particles 50 correspond approximately to the particles 50 in the first region R1. Therefore, it may be considered that the particles 50 in the first region R1 have their vertices 55a facing the first surface 112.

[0079] When the wick 13 is viewed from the opposite side of the first surface 112, the particles 50 constituting the wick 13 may be mostly composed of particles 50 with the side opposite the apex 55a facing the viewer. The side opposite the apex 55a facing the viewer means that when a particle 50 is viewed from the opposite side of the first surface 112, the apex 55a is hidden by other parts of the particle 50 and cannot be seen. The term "majority" means that the apex 55a accounts for 50% or more, 60% or more, or 70% or more. When the wick 13 is viewed from the opposite side of the first surface 112, the particles 50 that are visible and not hidden by other particles 50 correspond approximately to the particles 50 in the third region R3. Therefore, in the third region R3, the particles 50 with the side opposite the apex 55a facing the opposite side of the first surface 112 may be considered to be mostly composed of particles 50.

[0080] A plurality of particles 50 may be bonded to the first surface 112 by a sintering process. As shown in FIGS. 10A to 10C , the particle 50 may have a vertex 55a and a maximum portion 56 where the diameter around a center line connecting the vertex 55a and the opposite side of the vertex 55a is maximized. A large proportion of the particles 50 bonded to the first surface 112 may be bonded to the first surface 112 at any point within the range from the vertex 55a to the maximum portion 56. The above-mentioned large proportion may be 40% or more, 50% or more, or 60% or more of all the particles 50 bonded to the first surface 112.

[0081] The first surface 112 has a heat source located above the center, while most of the area outside the center is distant 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 also includes a second path in which heat is first diffused from the center of the base 11 to the surrounding area along the first surface 112, then transferred to the refrigerant via the first surface 112, where it is rapidly dissipated via a phase transition and reflux of the refrigerant. When the heat source's heat quantity 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 the heat source, which may result in less liquid-phase refrigerant being returned directly below the heat source. In this case, the heat dissipation characteristics of the vapor chamber 1 decrease due to the decrease in liquid-phase refrigerant being returned directly below the heat source. As explained above, the particles 50 tend to move the liquid refrigerant from the apex 55a to the opposite side. Therefore, by distributing the plurality of particles 50 in the above-described direction, and by bonding the plurality of particles 50 to the first surface 112 as described above, the liquid refrigerant acts to move slightly away from the first surface 112 at the portion of the first surface 112 that is far from the heat source. This reduces the possibility of the liquid refrigerant transitioning to a gas phase at the portion of the first surface 112 that is far from the heat source. This makes it possible to supply a large amount of liquid refrigerant close to the area directly below the heat source, even when the heat source has a large amount of heat. Therefore, even when the heat source has a large amount of heat, the vapor chamber 1 can achieve good heat dissipation characteristics.

[0082] 12A and 12B are diagrams showing the wick of embodiment 2 and the wick of embodiment 3, respectively. The heat dissipation member of embodiment 2-3 differs in the particles 70 that make up the wick 13, and the configuration other than the wick 13 may be the same as that of embodiment 1. Furthermore, the multiple configurations described in embodiment 1 may also be applied to the wick 13 of embodiment 2-3.

[0083] The wick 13 may be configured by combining multiple particles 70, each of which is a mixture of first-type particles 71 and second-type particles 72 having different shapes. The first-type particles 71 may be the particles 50 described in the first embodiment, and the second-type particles 72 may be spherical particles. The spherical shape does not necessarily mean a strict sphere or an oblate sphere, but also includes spheres with distortions or small jagged edges. The particles 70 of the second embodiment shown in FIG. 12A are a mixture of the second-type particles 72 and the first-type particles 71 at a mass ratio of 75:25. The particles 70 of the third embodiment shown in FIG. 12B are a mixture of the second-type particles 72 and the first-type particles 71 at a mass ratio of 50:50.

[0084] The mixing ratio of the second type particles 72 to the first type particles 71 may be 25:75 by mass or may be various ratios.

[0085] By mixing the first type particles 71 and the second type particles 72 to form the wick 13, it is possible to adjust the heat dissipation characteristics of the vapor chamber 1 by adjusting the mixture ratio. This makes it easy to achieve heat dissipation characteristics that correspond to the properties of the heat source to be dissipated.

[0086] FIG. 13 is a graph showing the characteristics of a heat dissipation member having a wick with different particle mixture ratios. The legend of the graph indicates the mixture ratio of "second-type particles 72:first-type particles 71." The input power on the horizontal axis corresponds to the amount of heat output from the heat source. As shown in the graph, the higher the mixture ratio of first-type particles 71, the greater the input power at which thermal resistance is minimized. Furthermore, gradually decreasing the mixture ratio of first-type particles 71 gradually decreases the input power at which thermal resistance is minimized. Therefore, when the heat amount desired to exert the highest heat dissipation capacity is planned using the above mixture ratio, the heat dissipation characteristics of the vapor chamber 1 can be easily adjusted to reduce the thermal resistance at that heat amount.

[0087] In the above example, the particles 50 of the first embodiment are used as the first type particles 71, but the particles 60 of the fourth embodiment described below may also be used as the first type particles 71. In this configuration, the same effect is achieved.

[0088] 14 is a diagram showing particles 60 constituting the wick 13 of embodiment 4. In embodiment 4, the shape of the particles 60 constituting the wick 13 is different, and the configuration other than the wick 13 may be the same as embodiment 1. Furthermore, the arrangement and distribution pattern of the plurality of particles 50 and the voids G, as well as the configuration related to the gaps g provided between the protrusions 51 of each particle 50, described in embodiment 1, may also be applied to the wick 13 of embodiment 4.

[0089] However, the particles 60 of embodiment 4 do not have a structure in which the protrusions 51 have directional properties, as in embodiment 1. Furthermore, the particles 60 of embodiment 4 do not have the cone-shaped portions 55 of embodiment 1. Therefore, the configuration regarding the directionality of the protrusions 51 and the configuration regarding the cone-shaped portions 55 shown in embodiment 1 do not apply to the wick 13 of embodiment 4.

[0090] The wick 13 of the fourth embodiment may be configured by bonding multiple particles 60 together, as in the first embodiment. The wick 13 may have a structure in which multiple particles 60 are fixed together as a whole by bonding portions of adjacent particles 60 together. Each particle 60 may be made of a metal such as copper. Bonding between adjacent particles 60 may be achieved by a sintering process to the extent that the multiple particles 60 do not become densified. The particle diameter of the particles 60 may be 1 μm to 1000 μm, 5 μm to 700 μm, or 10 μm to 500 μm. The particle diameter D50 of the particles 60 may be 5 μm, 50 μm, or 100 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.

[0091] Each of the plurality of particles 60 may have a structure in which a plurality of protrusions 61, each having a maximum thickness partway from the base to the tip, protrude in at least four mutually different directions, as shown in Fig. 14. The four directions may include components of three-dimensional directions. In other words, when the four directions are referred to as 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.

[0092] The above structure of the particle 60 can be produced, for example, by first forming a plurality of fine powder particles by atomization, and then sintering the gathered fine powder particles to a degree that does not cause the fine powder particles to become denser. Fine powder particles that are nearly spherical are formed by atomization, and the surrounding fine powder particles are sintered together, forming protrusions 61 that have a maximum thickness point T midway from the base to the tip.

[0093] The bonding between the fine powder particles by the sintering process is stronger than the bonding between the particles 60 in the wick 13. Therefore, by measuring the width of the bonding area through SEM observation, it is possible to distinguish between the former type of bonding and the latter type of bonding. By using the latter type of bonding as the boundary between one particle 60 and another particle 60, it is possible to identify the individual particles 60 and measure the particle size of each particle 60.

[0094] Although the particle 60 in FIG. 14 has a plurality of protrusions 61 spaced apart, some or all of the protrusions 61 may be close to each other, with minute gaps between the protrusions 61 .

[0095] According to the wick 13 of the fourth embodiment, the plurality of protrusions 61 of the particles 60 can easily realize a wick 13 that includes many large voids G between the plurality of particles 60. That is, in the manufacturing stage of the wick 13, when a powder of the plurality of particles 60 is laid in the hollow portion 111, many of the protrusions 61 cause a large number of catches between adjacent particles 60. These catches then create many large voids G between the plurality of particles 60. Then, by bonding the plurality of particles 60 through a sintering process, a wick 13 that includes many large voids G can easily be realized.

[0096] Furthermore, the surface of each particle 60 may contain small gaps g between the multiple protrusions 61. Therefore, the wick 13 contains large gaps G, small gaps G, and even smaller gaps g dispersed therein. This structure allows for smooth retention and transport of liquid-phase refrigerant and discharge of gas-phase refrigerant, achieving good heat dissipation characteristics for the vapor chamber 1. In particular, heat dissipation characteristics suitable for dissipating a large amount of heat with low thermal resistance can be achieved.

[0097] Figure 15 shows a cross-sectional view of a wick 13 made up of the particles 60 of Figure 14. Larger particles 60 are made up of a greater number of fine particles gathered together. Therefore, in larger particles 60, minute gaps g60 exist even within the particle 60. As shown in Figure 15, when observing a cross section, gaps g60 that do not connect to the outside may be located within the particle 60. While these gaps g60 do not connect to the outside in a two-dimensional cross section, they continue to the outside via other gaps g60 in three-dimensional space.

[0098] The wick 13 is formed by combining a plurality of particles 60 varying in size, which can cause variations in the size of the voids within the wick 13. The voids include minute gaps g60 contained within a single particle 60. The variation in void size increases the retention and transport capacity of the liquid refrigerant by the wick 13, thereby achieving better heat dissipation characteristics for the vapor chamber 1.

[0099] <Support structure of base> Figure 16 is a plan view showing the support structure of the base 11B in embodiment 5. The heat dissipation member 10B and vapor chamber 1B of embodiment 5 may have the same configuration as those of embodiments 1 and 2, except for the support structure of the base 11B. In Figure 16, the heat source mounting portion 15B is indicated by a dashed line.

[0100] The base 11B may have a support 116 that overlaps with the mounting portion 15B in a planar perspective view. The support 116 may be thicker than the wall-shaped support 117, 118. The support 116 may have a planar shape such as a circular, square, or elliptical shape. The support 116 may be connected to surrounding wall-shaped support 117. The support 116 to 118 may be positioned from the inner top surface to the inner bottom surface of the hollow portion 111 and may be configured to support the hollow portion 111 from the inside. In this structure, the side surface of the support 116 may be considered as a first surface 112 that applies heat to the wick 13.

[0101] <Surface Treatment of Base> Fig. 17A is a perspective view showing the heat dissipation member and vapor chamber in embodiment 6. Fig. 17B is a cross-sectional view taken along line C1-C1 in Fig. 17A. Fig. 18A is a perspective view showing the heat dissipation member and vapor chamber in embodiment 7. Fig. 18B is a cross-sectional view taken along line C2-C2 in Fig. 18A. In Figs. 17B and 18B, the wick 13 is indicated by shading. The heat dissipation members 10C and 10D and vapor chambers 1C and 1D in embodiments 6 and 7 may have the same configuration as those in embodiments 1 to 5, except for the bases 11C and 11D.

[0102] The bases 11C and 11D may have a hollow portion 111 separated into a plurality of parts. The bases 11C and 11D may have an insulating substrate 11Ca, a plurality of box bodies 11Cb joined to the insulating substrate 11Ca, and a plate material 11Cc joined to the insulating substrate 11Ca. The base 11C may have a plurality of small box bodies 11Cb arranged in a plurality of rows. The base 11D may have a plurality of large box bodies 11Cb arranged in a plurality of rows. The large box bodies 11Cb may have a rectangular planar shape, and the small box bodies 11Cb may have a planar shape closer to a square than the large box bodies 11Cb. The insulating substrate 11Ca may be made of silicon nitride (Si ３ N ４ ), silicon carbide (SiC), aluminum nitride (AlN), aluminum oxide (Al ２ O ３The plurality of box bodies 11Cb may be made of a metal such as copper and may have cavities that are open on one side. The open side of the cavity may be joined to the insulating substrate 11Ca, so that the cavity forms the hollow portion 111. The plate material 11Cc may be made of a metal such as copper and may be joined to the insulating substrate 11Ca on the side opposite to the box bodies 11Cb.

[0103] 17B and 18B, the bases 11C and 11D may have a metal film 11Cd on a portion of their outer surfaces. The metal film 11Cd may be a Ni (nickel) plated film, a Ni-Au (gold) plated film, a Ni-pd (palladium)-Au plated film, or an Ag (silver) plated film.

[0104] The metal film 11Cd may be located on the outer surfaces of the bases 11C and 11D, excluding the outer surface of the insulating substrate 11Ca. On the outer surface of the box body 11Cb, the metal film 11Cd may be located on the entire outer surface, or on a mounting portion 15C for a heat source such as a semiconductor chip. On the plate material 11Cc, the metal film 11Cd may be located on the entire outer surface of the plate material 11Cc that is exposed to the outside, or on a joining portion 16C to which a cooling body (e.g., a heat sink, a heat dissipation fin, etc.) is joined.

[0105] The insulating substrate 11Ca may be omitted, or the box body 11Cb may be joined to the plate material 11Cc. In this configuration, the metal film 11Cd may be positioned on the entire outer surface exposed to the outside, or the metal film 11Cd may be omitted from the area excluding the heat source mounting portion 15C and the cooling body joining portion 16C.

[0106] (Functional Module) FIGS. 19A to 20C are diagrams illustrating functional modules according to embodiments 8 to 12 of the present disclosure, respectively. Functional modules 400A to 400E according to embodiments 8 to 12 each include a heat-generating functional component 410A to 410E and a vapor chamber 1 according to an embodiment in which the functional component 410A to 410E is mounted. Specific examples of functional modules 400A to 400E are described below, but the following structure is merely an example, and various modifications to the detailed structure are possible. Detailed illustrations of the internal structure of the vapor chamber 1 are omitted in FIGS. 19A to 20C. The vapor chamber 1 may be replaced with any of the vapor chambers 1A to 1D according to the other embodiments described above.

[0107] (Functional Module of Embodiment 8) The functional module 400A of Embodiment 8 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.

[0108] The functional component 410A may be mounted on the vapor chamber 1 via a submount 420. The submount 420 is a substrate smaller than the vapor chamber 1 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 401. The mounting portion 401 corresponds to the mounting portion for the heat source in the vapor chamber 1.

[0109] The vapor chamber 1 has a sidewall 430 that surrounds the periphery of the mounting portion 401 of the base 11, and the mounting portion 401 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.

[0110] According to the functional module 400A of embodiment 8, a large amount of heat can be dissipated from the functional component 410A, which is a light-emitting element, via the vapor chamber 1. 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 1 can ensure uniform heat distribution among the multiple functional components 410A, thereby ensuring uniform brightness among the multiple functional components 410A.

[0111] (Functional Module of Embodiment 9) The functional module 400B of Embodiment 9 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 section 401. 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 section 401, 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.

[0112] The vapor chamber 1 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 1 from below via the opening 443a, and may conduct heat from the vapor chamber 1 to the outside of the shield case 444.

[0113] According to the functional module 400B of the ninth embodiment, a large amount of heat can be dissipated from the functional component 410B, which is a signal processing circuit, via the vapor chamber 1. This allows for stable transmission of wireless signals, which contributes to increasing the power of the wireless signals, i.e., increasing the output of wireless radio waves, and reducing the module volume.

[0114] (Functional Module of Embodiment 10) The functional module 400C of embodiment 10 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.

[0115] One or more functional components 410C may be mounted on a module substrate 451 such as a PCB (Printed Circuit Board), while the vapor chamber 1 may be incorporated so that it contacts the functional components 410C from the side opposite 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 1. Furthermore, the functional module 400C may have a cooling device 454, such as a fan, that cools the heat dissipation component 453.

[0116] According to the functional module 400C of embodiment 10, a large amount of heat can be dissipated from the functional components 410C, such as the LSI and memory IC, via the vapor chamber 1. This allows stable computational processing by the functional components 410C. This allows for the high computing power of the LSI to be accommodated, resulting in a functional module 400C with high computing power. Furthermore, the vapor chamber 1 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.

[0117] (Functional Module of Embodiment 11) The functional module 400D of Embodiment 11 may be a sensor module in which an image sensor is used as a functional component 410D. The vapor chamber 1 may have a convex portion 461 formed by a portion of the base 11 protruding, and the mounting portion 401 may be located on top of the convex portion 461.

[0118] 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 1 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 1.

[0119] According to the functional module 400D of the eleventh embodiment, a large amount of heat can be dissipated from the functional component 410D, which is an image sensor, via the vapor chamber 1. 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, which contributes to improving the functionality of the functional module 400D.

[0120] (Functional Module of Embodiment 12) The functional module 400E of Embodiment 12 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 1 and multiple functional components 410E, and the multiple vapor chambers 1 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 chambers 1 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 1 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 1 , the functional component 410E, the insulating plate 471 and the heat sink 474 may be sealed with a molding material 473 .

[0121] According to the functional module 400E of the twelfth embodiment, a large amount of heat can be dissipated from the functional component 410E, which is a power semiconductor, via the vapor chamber 1. Therefore, a high-output power semiconductor that generates a large amount of heat can be used as the functional component 410E, and further, the functional module 400E can be highly integrated and miniaturized.

[0122] The embodiments of the present disclosure have been described above. However, the present invention is not limited to the above embodiments. For example, in the above embodiments, the base 11 is shown to be flat, but the base 11 may have a shape including a pipe. Other details shown in the embodiments can be modified as appropriate without departing from the spirit of the invention.

[0123] An embodiment of the present disclosure is described below. In one embodiment, (1) a heat dissipation member includes: a base having a hollow portion and a first surface exposed in the hollow portion; and a wick located in the hollow portion and in contact with the first surface, wherein the wick has a plurality of particles bonded to one another and a plurality of voids located between the plurality of particles, and each of the plurality of particles has a structure in which a plurality of protrusions protrude obliquely radially from an imaginary central axis and are arranged in a plurality of stages along the imaginary central axis.

[0124] (2) The heat dissipation member of (1) above has a structure in which the imaginary central axis is branched into a plurality of parts along the way.

[0125] (3) In the heat dissipation member of (1) or (2) above, the particles have a cone-shaped portion in which the diameter of the particles gradually increases from one end of the imaginary central axis to the middle.

[0126] (4) In the heat dissipation member according to any one of (1) to (3) above, each of the plurality of particles has a plurality of valleys located between the plurality of protrusions, and 20% or more of the plurality of valleys visible from the surface are gentle valleys having rounded bottoms.

[0127] (5) In the heat dissipation member of any one of (1) to (4), the plurality of particles include first-shaped particles having a thickness increase rate of less than 7.5 times around the imaginary central axis and second-shaped particles having a thickness increase rate of 7.5 times or more around the imaginary central axis, and when a region where the wick is located is divided into three from the first surface to the end opposite to the first surface and the three regions are referred to as a first region, a second region, and a third region from the side closest to the first surface, the first-shaped particles are distributed more frequently in the first region than the second-shaped particles, and the second-shaped particles are distributed more frequently in the third region than the first-shaped particles.

[0128] (6) The heat dissipation member of any one of (1) to (5) above has a vertex portion that is one end of the imaginary central axis, and when the wick is viewed from the first surface, the vertices of 40% or more of the particles face toward the first surface.

[0129] (7) A heat dissipation member comprises: a base having a hollow portion and a first surface exposed in the hollow portion; and a wick located in the hollow portion and in contact with the first surface, wherein the wick has a plurality of particles bonded to each other and a plurality of voids located between the plurality of particles, and each of the plurality of particles has a structure in which a plurality of protrusions having a maximum thickness point protrude in at least four different directions.

[0130] (8) In the heat dissipation member of any one of (1) to (7) above, the three adjacent protrusions are called the first protrusion, the second protrusion, and the third protrusion, and when the first protrusion has a maximum thickness point midway from the base to the tip, the gap between the first protrusion and the second protrusion and the gap between the first protrusion and the third protrusion are connected closer to the base than the maximum thickness point of the first protrusion.

[0131] (9) In the heat dissipation member according to any one of (1) to (8) above, in a cross section of the wick, the plurality of voids include a first void having a width greater than the average particle size of the particles.

[0132] (10) In the heat dissipation member of (9) above, there are four or more connection points between the first void portion and another void portion in the cross section of the wick.

[0133] (11) In the heat dissipation member of any one of (1) to (10) above, the particles have gaps between multiple protrusions, and in the cross section of the wick, the width of the gaps is smaller than the width of the void portions connected to the gaps.

[0134] (12) The heat dissipation member according to any one of (1) to (11) above, wherein each of the plurality of particles has a gap between the plurality of protrusions, and the plurality of particles includes a first particle and a second particle in which the gaps between two adjacent particles are in contact with each other.

[0135] (13) The heat dissipation member of any one of (1) to (12) above has a cross section in which the first surface is connected to the end of the wick on the opposite side of the first surface via the plurality of voids.

[0136] (14) The heat dissipation member according to any one of (1) to (13) above, wherein in a cross section of the wick, the plurality of voids include second voids that are larger in the normal direction than the average particle diameter of the plurality of particles and are in contact with the first surface.

[0137] (15) The heat dissipation member of any one of (1) to (14) above, wherein the hollow portion includes an area between two opposing inner surfaces where the wick is not located, and the particles have gaps between a plurality of protrusions, and the gaps are in contact with the area.

[0138] (16) The heat dissipation member of any one of (1) to (13) above, wherein the base has a second surface exposed to the hollow portion and facing the first surface, the hollow portion has a space between the wick and the second surface, and the space has irregularities in the direction in which the first surface and the second surface face each other.

[0139] (17) In the heat dissipation member of (3) above, when viewed from one direction, the directions of the apexes of the cone-shaped portions of the plurality of particles are oriented in a plurality of dispersed directions.

[0140] (18) In the heat dissipation member of (3) or (17) above, the plurality of particles include a third particle having an apex of the cone-shaped portion facing toward the adjacent void portion.

[0141] (19) In the heat dissipation member of (3), (17) or (18) above, the plurality of particles include a fourth particle having a side opposite to the apex of the cone-shaped portion facing the adjacent void portion.

[0142] In one embodiment, (20) a vapor chamber includes: the heat dissipation member according to any one of (1) to (19) above; and a refrigerant located in the hollow portion.

[0143] In one embodiment, (21) a functional module includes: a heat-generating functional component; and (20) a vapor chamber in which the functional component is mounted.

[0144] The present disclosure can be used for heat dissipation members, vapor chambers, and functional modules.

[0145] 1, 1B, 1C Vapor chamber 10, 10B, 10C, 10D Heat dissipation member 11, 11B, 11C, 11D Base 11Cd Metal film 13 Wick 50 Particle 50A First particle 50B Second particle 50C Third particle 50D Fourth particle 50H1 First shaped particle 50H2, 50H2b Second shaped particle 51, 51a, 51b Projection 51A First projection 51B Second projection 51C Third projection 53 Virtual central axis 55 Cone-shaped portion 55a Apex portion 57 Valley portion 57a ​​Gentle valley portion 60 Particle g60 Gap 61 Projection 70 Particle 71 First type particle 72 Second type particle 111 Hollow portion 111A, 111B Region 111c Space 111c1, 111c2 Concave and convex 112 First surface 113 Second surface 115-118 Support cn Connection point g, g1, g2, gA, gB Gap G Air gap G1 First air gap G2 Second air gap H Communication path T Maximum point wg, wG, wG2 Width R1 First region R2 Second region R3 Third region 400A-400E Functional module 410A-410E Functional part

Claims

1. A heat dissipation component comprising: a substrate having a hollow portion and a first surface exposed in the hollow portion; and a wick located in the hollow portion and in contact with the first surface, wherein the wick has a plurality of particles bonded to one another and a plurality of voids located between the plurality of particles, and each of the plurality of particles has 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.

2. The heat dissipation member according to claim 1, wherein the imaginary central axis has a structure in which it branches into multiple parts along the way.

3. A heat dissipation member according to claim 1 or claim 2, wherein the particle has a cone-shaped portion in which the diameter of the particle gradually increases from one end of the imaginary central axis to the middle.

4. A heat dissipation member according to any one of claims 1 to 3, wherein each of the plurality of particles has a plurality of valleys respectively located between the plurality of protrusions, and 20% or more of the plurality of valleys visible from the surface are gentle valleys having rounded bottoms.

5. A heat dissipation member according to any one of claims 1 to 4, wherein the plurality of particles include first-shaped particles whose rate of increase in thickness around the imaginary central axis is less than 7.5 times and second-shaped particles whose rate of increase in thickness around the imaginary central axis is 7.5 times or more, and when the region in which the wick is located is divided into three from the first surface to the opposite end of the first surface and the three regions are referred to as a first region, a second region, and a third region in order from the side closest to the first surface, the first-shaped particles are distributed more frequently in the first region than the second-shaped particles, and the second-shaped particles are distributed more frequently in the third region than the first-shaped particles.

6. A heat dissipation member according to any one of claims 1 to 5, wherein each of the plurality of particles has an apex portion which is one end of the imaginary central axis, and when the wick is viewed from the first surface, 40% or more of the apexes of the particles face towards the first surface.

7. A heat dissipation component comprising: a substrate having a hollow portion and a first surface exposed in the hollow portion; and a wick located in the hollow portion and in contact with the first surface, wherein the wick has a plurality of particles bonded to one another and a plurality of voids located between the plurality of particles, and each of the plurality of particles has a structure in which a plurality of protrusions having a maximum thickness point protrude in at least four different directions.

8. A heat dissipation member according to any one of claims 1 to 7, wherein three adjacent protrusions are referred to as a first protrusion, a second protrusion, and a third protrusion, and when the first protrusion has a point of maximum thickness midway from the base to the tip, the gap between the first protrusion and the second protrusion and the gap between the first protrusion and the third protrusion are connected on the base side of the point of maximum thickness of the first protrusion.

9. A heat dissipation member according to any one of claims 1 to 8, wherein in a cross section of the wick, the plurality of voids include a first void having a width greater than the average particle size of the particles.

10. The heat dissipation member according to claim 9, wherein there are four or more connection points between the first void portion and another void portion in the cross section of the wick.

11. A heat dissipation member according to any one of claims 1 to 10, wherein the particles have gaps between a plurality of protrusions, and in the cross section of the wick, the width of the gaps is smaller than the width of the void portions connected to the gaps.

12. A heat dissipation member according to any one of claims 1 to 11, wherein each of the plurality of particles has a gap between the plurality of protrusions, and the plurality of particles includes a first particle and a second particle in which the gaps between two adjacent particles are in contact with each other.

13. A heat dissipation member according to any one of claims 1 to 12, wherein in a cross section of the wick, the first surface is connected to the end of the wick on the opposite side of the first surface via the plurality of voids.

14. A heat dissipation member described in any one of claims 1 to 13, wherein in the cross section of the wick, the plurality of voids include a second void that is larger in the normal direction than the average particle size of the plurality of particles and is in contact with the first surface.

15. A heat dissipation member according to any one of claims 1 to 14, wherein the hollow portion includes an area between two opposing inner surfaces where the wick is not located, and the particles have gaps between a plurality of protrusions, and the gaps are in contact with the area.

16. A heat dissipation member described in any one of claims 1 to 13, wherein the base has a second surface exposed to the hollow portion and facing the first surface, the hollow portion has a space between the wick and the second surface, and the space has irregularities in the direction in which the first surface and the second surface face each other.

17. A heat dissipation member according to claim 3, wherein, when viewed from one direction, the directions of the apexes of the cone-shaped portions of the plurality of particles are oriented in a plurality of dispersed directions.

18. A heat dissipation member according to claim 3 or claim 17, wherein the plurality of particles includes a third particle having an apex of the cone-shaped portion facing toward an adjacent void portion.

19. A heat dissipation member according to claim 3, claim 17 or claim 18, wherein the plurality of particles includes a fourth particle having the side opposite to the apex of the cone-shaped portion facing the adjacent void portion.

20. A vapor chamber comprising: a heat dissipation member according to any one of claims 1 to 19; and a refrigerant located in the hollow portion.

21. A functional module comprising: a heat-generating functional component; and the vapor chamber according to claim 20, in which the functional component is mounted.

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