JP7639307B2 - Heat dissipation device - Google Patents

Description

This disclosure relates to a heat dissipation device.

In recent years, advances in semiconductor technology have led to the development of semiconductor chips with higher output and higher voltage resistance than ever before. Furthermore, as systems become more sophisticated, electronic components, including semiconductor elements, are becoming more functional. As a result, the amount of heat generated by semiconductor elements, i.e., heat-generating components, is increasing. For example, the mainstream substrate material for high-frequency semiconductor elements has been gallium arsenide (GaAs). However, in recent years, gallium nitride (GaN) has rapidly become popular as a substrate material for high-frequency semiconductor elements. This has resulted in a several-fold increase in the output of the elements. At the same time, the amount of heat generated by heat-generating components, including the semiconductor elements, has also increased several-fold.

In order to deal with the increased heat generated by these semiconductor elements, it is necessary to improve the cooling structure. For cooling, heat must be transferred from the parts that generate a lot of heat, such as the semiconductor elements included in the heat-generating components, to heat dissipation parts such as fins or heat exchangers. When semiconductor elements that generate a large amount of heat are mounted by surface mounting in electronic components, heat-generating components such as semiconductor elements are attached to a printed wiring board, as in JP 2017-5093 A (Patent Document 1), for example.

However, printed wiring boards are generally made of resin materials and therefore do not have good thermal conductivity. For this reason, when heat-generating components that generate a lot of heat, such as semiconductor elements, are mounted on a printed wiring board, the heat-generating components become very hot. In order to improve the thermal conductivity of the printed wiring board, in JP 2017-5093 A, a heat dissipation mechanism using thermal vias is formed in the printed wiring board.

JP 2017-5093 A

In JP 2017-5093 A, high heat dissipation performance from the heat generating component to the heat dissipation fin side is obtained by filling the above-mentioned thermal vias with a heat conductive core. However, in recent years, electronic components have become smaller, more functional, and more highly integrated. This has resulted in high density wiring on the back side or around the electronic components. This has resulted in a high heat density in the heat generating components, and the problem is that the cooling performance is insufficient with only the heat dissipation mechanism disclosed in JP 2017-5093 A.

The present disclosure has been made in consideration of the above problems. Its purpose is to provide a heat dissipation device that can dissipate heat generated by heat-generating components arranged on a substrate with high efficiency.

The heat dissipation device according to the present disclosure includes a mounting component including a heat generating component and a package for housing the heat generating component, a first main surface on which a first hole is formed and on which a surface wiring is formed by joining a conductive film pattern formed on the bottom surface of the package and electrically connecting with the heat generating component with a conductive bonding member, a second main surface opposite to the first main surface, a heat conducting portion including an area overlapping with the heat generating component in a plan view, penetrating from the first main surface to the second main surface, and having a first heat conducting portion formed of a first conductive member filled in the first hole and connected with the surface wiring, and an inner layer wiring formed inside to be connected with the heat conducting portion. The first conductive member has a first thread groove formed on an outer peripheral surface, and the first hole has a second thread groove formed on an inner peripheral surface and the inner peripheral surface is covered with an inner wall conductive film, and the first thread groove and the second thread groove are engaged with each other.

This disclosure provides a heat dissipation device that can dissipate heat generated by heat-generating components arranged on a substrate with high efficiency.

1 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a first embodiment. 11 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a second embodiment. FIG. 11 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a third embodiment. FIG. 13 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a first example of embodiment 4. FIG. 13 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a second example of the fourth embodiment. FIG. 13 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a third example of the fourth embodiment. FIG. 4 is a flowchart showing a manufacturing process of a substrate included in the heat dissipation device of the first embodiment. 13 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a fifth embodiment. FIG. 6 is a schematic cross-sectional view showing a bonding step between a substrate and a mounted component in the manufacturing process of the heat dissipation device of FIG. 5. 22 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a first example of embodiment 6. FIG. 23 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a second example of the sixth embodiment. FIG. FIG. 23 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a third example of the sixth embodiment. 22 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a fourth example of the sixth embodiment. FIG. FIG. 23 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a fifth example of the sixth embodiment. 23 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a first example of embodiment 7. FIG. 13 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a second example of the seventh embodiment. FIG. 16 is a schematic cross-sectional view showing a step of inserting a heat conductive portion into a hole in a substrate as a first step in the manufacturing process of the heat dissipation device of FIG. 15. 16 is a schematic cross-sectional view showing a bonding step of a heat conductive portion as a second step in the manufacturing process of the heat dissipation device of FIG. 15. 13 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a first example of embodiment 8. FIG. 13 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a second example of the eighth embodiment. FIG. 13 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a third example of the eighth embodiment. FIG. 23 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a fourth example of the eighth embodiment. FIG. 13 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a fifth example of the eighth embodiment. FIG. FIG. 23 is a schematic cross-sectional view showing a configuration of a heat dissipation device according to a sixth example of the eighth embodiment.

The present embodiment will be described below with reference to the drawings. For ease of explanation, the X, Y, and Z directions are introduced.

Embodiment 1.
First, referring to FIG. 1, the general structural features of the heat dissipation device according to the present embodiment will be described. FIG. 1 is a schematic cross-sectional view showing the structure of the heat dissipation device according to the first embodiment. Referring to FIG. 1, the heat dissipation device 100a according to the present embodiment mainly includes a substrate 11, a mounted component 21, and a heat dissipation member 31. The substrate 11 has a first main surface 11a which is one of the main surfaces, and a second main surface 11b which is the other main surface opposite to the first main surface 11a. In FIG. 1, the first main surface 11a is the uppermost surface in the Z direction of the substrate 11, particularly the substrate body 12. In FIG. 1, the second main surface 11b is the lowermost surface in the Z direction of the substrate 11, particularly the substrate body 12. The mounted component 21 is placed on the first main surface 11a of the substrate 11 via a solder ball 32 which is a bonding material having high thermal conductivity. The mounted component 21 includes a heat generating component 22 which generates heat when driven. That is, a heat generating component 22 is disposed above the first main surface 11 a of the substrate 11 .

The substrate 11 is a plate material having, for example, a rectangular planar shape, mainly composed of a substrate body 12. That is, the substrate body 12 of the substrate 11 is a plate material having a rectangular first main surface 11a and a second main surface 11b in a direction along the XY plane, and having a certain thickness in the Z direction. The substrate 11 includes a heat conductive portion 13 and an inner layer wiring 14. The heat conductive portion 13 has a function of transmitting heat generated by the heat generating component 22, for example, from the upper side to the lower side in the Z direction of the figure. For this reason, the heat conductive portion 13 extends along the Z direction. The inner layer wiring 14 is formed so as to be connected to the heat conductive portion 13 within the substrate 11. Here, the inner layer wiring 14 is formed so as to be thermally and electrically connected to the heat conductive portion 13 within the substrate 11.

The thermal conductive portion 13 has a first thermal conductive portion 13a. The first thermal conductive portion 13a includes an area that overlaps with the heat generating component 22 in a plan view. In FIG. 1, the first thermal conductive portion 13a overlaps with the heat generating component 22 in a plan view. The first thermal conductive portion 13a is arranged so as to fill almost the entire inside of the hole portion 15 (first hole portion) formed to penetrate the substrate 11, particularly the substrate body 12, from the first main surface 11a to the opposite second main surface 11b. That is, the first thermal conductive portion 13a is arranged so as to penetrate the substrate 11, particularly the substrate body 12, from the first main surface 11a to the second main surface 11b. The first thermal conductive portion 13a is, for example, a structure made of a conductive material arranged in the hole portion 15 (first hole portion). Specifically, the first thermal conductive portion 13a is formed of a metal lump of a material with high thermal conductivity such as copper. In what follows, such metal blocks will be referred to as core materials.

In other words, the first heat conducting portion 13a is formed by a first conductive member filled in a hole portion 15 (first hole portion) formed in the substrate 1. The first conductive member has a first screw groove formed on its outer peripheral surface. Here, the outer peripheral surface of the first conductive member refers to the surface between the surface of the first conductive member facing the heat generating component 22 and the surface opposite to the surface facing the heat generating component 22. Also, the hole portion 15 (first hole portion) has a second screw groove formed on its inner peripheral surface. Here, the inner peripheral surface of the hole portion 15 (first hole portion) refers to the surface that becomes the inner wall of the hole portion 15 (first hole portion). The substrate 11 and the first heat conducting portion 13a are engaged by screwing so that the first screw groove and the second screw groove mesh with each other. In addition, the first conductive member, which is the first heat conducting portion 13a in FIG. 1, is formed from a portion formed inside the hole portion 15 (first hole portion) and a portion protruding outside the hole portion 15 (first hole portion). This gives the first conductive member a screw-like shape.

More specifically, the surface of the first conductive member opposite to the surface facing the heat generating member 22 protrudes outside the hole 15 (first hole). The portion of the first conductive member protruding outside the hole 15 (first hole) has a larger dimension in the X direction and Y direction than the portion formed inside. In other words, the portion of the first conductive member protruding outside the hole 15 (first hole) has a larger diameter than the hole 15 (first hole). This gives the first conductive member a screw-like shape. More specifically, the portion of the first conductive member protruding outside the hole 15 (first hole) becomes the head of the screw, and the portion formed inside the hole 15 (first hole) becomes the shaft of the screw. In the portion of the first conductive member protruding outside the hole 15 (first hole), the surface facing the substrate 11 is bonded to the substrate 11 by adhesive, solder, or the like. In this embodiment, the first conductive member has a portion protruding out of the hole 15 (first hole), but may have no protruding portion out of the hole 15 (first hole) if necessary. The first conductive member may also have a surface side facing the heat generating member 22 protruding out of the hole 15 (first hole). In this case, the protruding portion of either the surface side facing the heat generating member 22 or the surface side opposite the surface facing the heat generating member 22 of the first conductive member has the same dimensions in the X and Y directions as the portion formed inside. In other words, the protruding portion of either the surface side facing the heat generating member 22 of the first conductive member or the surface side opposite the surface facing the heat generating member 22 becomes the axis of the screw, similar to the portion formed inside the hole 15 (first hole). The heat dissipation device 100a of FIG. 1 will be described in more detail below.

<Board Configuration>
The substrate 11 is, for example, a printed wiring board. A substrate body 12 of the substrate 11 is formed from a generally known resin material. As described below, the substrate body 12 is formed by stacking a plurality of plate materials, each of which is thinner in the Z direction than the substrate 11 of FIG. 1, in the Z direction and integrating them. A pattern of inner layer wiring 14 is formed on one or the other main surface of each of the plurality of stacked thin plate materials. The pattern of the inner layer wiring 14 is, for example, a thin film pattern formed from copper.

The hole 15 penetrates the substrate body 12 from the first main surface 11a to the second main surface 11b of the substrate 11. The hole 15 (first hole) penetrating the substrate body 12 from the first main surface 11a to the second main surface 11b is formed in the center in the X direction in FIG. 1, and is formed to include an area that overlaps with the heat-generating component 22 in a plan view. In FIG. 1, only one such hole 15 (first hole) penetrating the substrate body 12 is formed in the center of the substrate body 12. The first heat-conducting part 13a is inserted inside this hole 15 (first hole).

The substrate 11 has multiple layers of inner wiring 14 formed at intervals in the Z direction. However, surface wiring 17 is formed on the first main surface 11a of the substrate 11. The pattern of the surface wiring 17 is formed from the same material and thickness as the pattern of the inner wiring 14. In other words, the surface wiring 17 is a thin film pattern made of, for example, copper.

<Configuration of mounted components>
The mounting component 21 includes a heat generating component 22 and a package 23. The heat generating component 22 is a semiconductor element having a semiconductor transistor or a diode formed on a substrate of, for example, silicon (Si), gallium nitride, or gallium arsenide. The heat generating component 22 generates heat by driving the semiconductor element. The package 23 is a case-shaped member formed of a single-layer or multi-layer resin substrate or a ceramic substrate. However, the package 23 may be a case-shaped member made of metal. The package 23 houses the heat generating component 22 inside. The package 23 is preferably any one selected from the group consisting of a gull-wing package, a flat-lead package, a QFN (Quad For Non-Lead) package, and a BGA (Ball Grid Array) package. The heat generating component 22 is bonded to the inside of the package 23, for example, on the bottom surface thereof, by a bonding layer 24 such as solder.

<Other materials>
A heat dissipation member 31 is bonded to the substrate 11 so as to contact the surface wiring on the second main surface 11b of the substrate 11. That is, the heat dissipation member 31 is bonded to the second main surface 11b side of the substrate 11, which is opposite to the first main surface 11a side on which the mounted components 21 including the heat generating components 22 are mounted. The heat dissipation member 31 is a commonly known heat sink made of, for example, copper. However, the heat dissipation member 31 is not limited to this, and other coolers may be used as the heat dissipation member 31.

Multiple solder balls 32 are arranged at intervals so as to contact the surface wiring 17 and plating film 17a on the first main surface 11a of the substrate 11. These solder balls 32 are arranged so as to contact the conductive film pattern formed on the bottom surface of the package 23. It is preferable that the conductive film pattern of the package 23 is electrically connected to the semiconductor element included in the heat-generating component 22. In this way, the solder balls 32 electrically connect the substrate 11 and the mounted component 21.

In this embodiment, the solder balls 32 are preferably made of a highly thermally conductive and reflowable joining material, such as a solder material containing a metal core or silver paste. This allows the solder balls 32 to connect the substrate 11 and the mounted components 21 with low thermal resistance.

<Operation of heat dissipation device>
The heat dissipation device 101 having the above configuration operates as follows. Heat generated in the heat generating component 22 by driving the semiconductor element is transferred through the package 23 and the solder balls 32 to the first heat conducting portion 13a of the substrate 11, which overlaps with the heat generating component 22 in a planar manner. The first heat conducting portion 13a can dissipate the heat to the heat dissipation member 31 directly below it. The first heat conducting portion 13a is also connected to the inner layer wiring 14 directly or via the inner wall conductive film 16 on the inner wall surface of the hole 15 (first hole) in which it is placed.

Next, the manufacturing process of the heat dissipation device 100a of FIG. 1, particularly the substrate 11, will be described using the flowchart of FIG. 7. FIG. 7 is a flowchart showing the manufacturing process of the substrate included in the heat dissipation device of embodiment 1. Referring to FIG. 7, a preparation process (S10) is performed first. Specifically, a plurality of thin rectangular resin plates to become the substrate body 12 are prepared. A wiring pattern, for example of copper, is formed on one or both main surfaces of each of the plurality of plates.

Next, the lamination process (S20) is performed. Each plate is stacked with a sheet called prepreg placed on top of it. Then, the bonding process (S30) is performed. The stacked plates are exposed to high temperature and high pressure. This causes the prepreg to bond the plates together. The above processes (S20) and (S30) may be repeated multiple times until the required thickness of the substrate 11 in the Z direction is achieved.

When the substrate 11 is formed to the required thickness, a hole 15 (first hole) is formed through the substrate 11 so as to penetrate the entire substrate body 12 from the first main surface 11a to the second main surface 11b in the drilling process (S40). After that, a second thread groove is formed in the inner peripheral surface, which is the inner wall surface of the hole 15 (first hole), or in the inner wall conductive film 16 covering the inner peripheral surface. In addition, a thin copper film may be formed as the inner wall conductive film 16 on the inner wall surface of this hole 15 (first hole), for example, by a plating process.

Then, a first thread groove is formed on the outer peripheral surface of the first conductive member of the first heat conducting portion 13a. In addition, a portion of the first conductive member that is formed outside the hole portion 15 (first hole portion) is formed with a diameter larger than that of the hole portion 15 (first hole portion). The first conductive member of the first heat conducting portion 13a is inserted into the hole portion 15 (first hole portion) that penetrates the entire substrate 11. At this time, the substrate 11 and the first heat conducting portion 13a are engaged by screwing so that the first thread groove formed in the first conductive member and the second thread groove formed in the hole portion 15 (first hole portion) engage with each other. The first conductive member fills almost the entire hole portion 15. At least a part of the first conductive member contacts the inner layer wiring 14 exposed as the inner wall surface of the hole portion 15 (first hole portion), or the inner wall conductive film 16 covering the inner wall surface. The first heat conductive portion 13a is formed from a first conductive member, which is a core material that has been shaped into a metal block in advance. After the core material is inserted, a heat treatment process and a chemical process may be performed as necessary.

After that, if necessary, a hole-filling resin may be filled into the gap between the inner wall surface of the hole 15 in the substrate body 12 and the core material of the thermally conductive part 13 filled therein. In this way, the thermally conductive part 13 is fixed in the hole 15 without the need for a resin material.

Next, we will explain the effects of this embodiment.

The heat dissipation device according to the present disclosure includes a substrate 11 and a heat generating component 22. The heat generating component 22 is disposed on a first main surface 11a of the substrate 11. The substrate 11 includes a heat conducting portion 13 and an inner layer wiring 14. The heat conducting portion 13 transmits heat generated by the heat generating component 22. The inner layer wiring 14 is formed so as to be connected to the heat conducting portion 13 within the substrate 11. The heat conducting portion 13 has a first heat conducting portion 13a. The first heat conducting portion 13a includes an area overlapping with the heat generating component 22 in a plan view, and penetrates the substrate 11 from the first main surface 11a to the second main surface 11b opposite to the first main surface 11a. The first heat conducting portion 13a is formed by a first conductive member filled in a hole portion 15 (inside a first hole portion) formed in the substrate 11. The first conductive member has a first thread groove formed on its outer circumferential surface. The hole 15 (first hole) formed in the substrate 11 has a second screw groove formed on the inner circumferential surface. The first screw groove and the second screw groove are engaged. This has the advantage of providing a higher joint strength than when only adhesive and solder are used for the fixing method, and allows for highly efficient heat dissipation. In addition, the high joint strength reduces the occurrence of cracks in the solder at the joint. Furthermore, when attaching the first conductive member to the substrate 11, the member is attached by screwing, so that a press-in process is not required and the member can be easily attached. Furthermore, the first conductive member has a portion protruding out of the hole 15. Therefore, even if the thickness of the first conductive member in the Z direction is shorter than the thickness of the substrate 11 in the Z direction, the first conductive member can be fixed to the substrate 11 at the portion protruding out of the hole 15. Therefore, the first conductive member can be easily attached to the substrate 11 even if the thickness in the Z direction is different from the thickness in the Z direction of the substrate 11.

Embodiment 2.
FIG. 2 is a schematic cross-sectional view showing the configuration of the heat dissipation device of the second embodiment. In the following figures, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description of the configuration and features substantially similar to those in FIG. 1 will not be repeated. That is, in the following description of each example, the configuration and features different from those in FIG. 1 or other existing examples will be mainly described. With reference to FIG. 2, in this embodiment, the first heat conduction portion 13h is the first heat conduction portion 13a in FIG. 1 to which a heat dissipation fin is further formed. In detail, the first heat conduction portion 13h is the first heat conduction portion 13a to which a heat dissipation fin is formed on the surface opposite to the surface facing the heat generating component 22. In addition, the first conductive member which is the first heat conduction portion 13h is formed from a portion formed inside the hole portion 15 (first hole portion) and a portion protruding to the outside of the hole portion 15 (first hole portion) in the same manner as the first heat conduction portion 13a. The heat dissipation fin is formed on the portion protruding to the outside. That is, since the first conductive member has a portion protruding outward from the hole portion 15 (first hole portion), it is possible to form a heat dissipation fin on this protruding portion. Here, the first heat conductive portion 13h is engaged with the substrate 11 by screwing the first heat conductive portion 13h to the first conductive member so that the first screw groove formed in the first conductive member and the second screw groove formed in the hole portion 15 (first hole portion) engage with each other, as in the case of the first heat conductive portion 13a. However, if necessary, the first heat conductive portion 13h may be configured to be inserted into the hole portion 15 (first hole portion) by press-fitting without the first screw groove formed therein. In that case, the second screw groove is not formed on the inner peripheral surface of the hole portion 15 (first hole portion).

The following describes the additional effects of the second embodiment that are obtained in addition to those of the first embodiment. This also applies to the explanation of the effects of each of the following embodiments. Heat can be dissipated directly from the first heat conducting portion 13h, allowing for highly efficient heat dissipation. Although the figure shows a configuration that includes a heat dissipation member 31, heat can be dissipated from the heat dissipation fins formed on the first heat conducting portion 13h even in a configuration that does not include the heat dissipation member 31. The first heat conducting portion 13h has high bonding strength because the substrate 11 and the first heat conducting portion 13h are engaged with screws. Therefore, a high heat dissipation effect can be obtained by processing a portion into a large heat dissipation fin, etc.

Embodiment 3.
3, in this embodiment, the first heat conducting portion 13h is the first heat conducting portion 13a in FIG. 1 or the heat conducting portion 13h in FIG. 2, in which the heat dissipation member 31 and the first heat conducting portion 13 are fixed by a fastening member such as a screw. Here, the heat dissipation member 31 and the first heat conducting portion 13 are fixed by a fastening member in the heat dissipation device 100a in FIG. 1. As shown in FIG. 3, the first conductive member which is the first heat conducting portion 13i is formed of a portion formed inside the hole portion 15 (first hole portion) and a portion protruding to the outside of the hole portion 15 (first hole portion) like the first heat conducting portion 13a. In the first heat conducting portion 13i, a hole portion is formed on the surface opposite to the surface facing the heat generating component 22 in the portion protruding to the outside, and a screw groove is formed in the hole portion by tapping or the like. In other words, since the first conductive member has a portion that protrudes outward from the hole portion 15 (first hole portion), it is possible to form a hole portion and a screw groove in this portion that protrudes outward.

The heat dissipation member 31 is provided on the surface opposite to the surface facing the heat generating component 22 of the first heat conductive portion 13i. A hole is also formed in the heat dissipation member 31 at a portion overlapping the hole formed in the first heat conductive portion 13i. A fastening member such as a screw is inserted between the hole formed in the heat dissipation member 31 and the hole formed in the first heat conductive portion 13i. The heat dissipation member 31 and the first heat conductive portion 13i are fixed by this fastening member. Note that here, like the first heat conductive portion 13a, the first heat conductive portion 13i engages the substrate 11 and the first heat conductive portion 13h by screwing them together so that the first screw groove formed in the first conductive member and the second screw groove formed in the hole portion 15 (first hole portion) engage with each other. However, if necessary, the first heat conducting portion 13i may be configured so that the first thread groove is not formed and the first heat conducting portion 13i is inserted into the hole portion 15 (first hole portion) by press-fitting. In that case, the second thread groove is not formed on the inner circumferential surface of the hole portion 15 (first hole portion).

The following describes additional effects of the third embodiment in addition to those of the first and second embodiments. The heat dissipation device 100c can firmly attach even a large-area heat dissipation member 31 using fastening members, thereby improving cooling efficiency. In addition, the portion where the heat dissipation member 31 and the first heat conductive portion 13i are joined can be the portion of the first heat conductive portion 13i, so there is no need to provide holes in other portions of the substrate 11 for inserting joining members, and more space can be secured for arranging the inner layer wiring 14.

Embodiment 4.
FIG. 4 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a fourth embodiment. Referring to FIG. 4, in this embodiment, the heat dissipation device in any one of FIGS. 1 to 3 has a second heat conductive portion 13b. Here, the heat dissipation device in FIG. 1 having the second heat conductive portion 13b is shown. The second heat conductive portion 13b is arranged around the first heat conductive portion 13a with a gap therebetween in the X direction or Y direction of the figure. The second heat conductive portion 13b is also arranged so as to fill almost the entire inside of the hole portion 15 (second hole portion) formed, for example, extending in the Z direction of the figure, inside the substrate 11, particularly the substrate body 12. However, the second heat conductive portion 13b is arranged with a gap from at least one of the first main surface 11a and the second main surface 11b. The second heat conductive portion 13b is a structure made of a conductive material arranged, for example, inside the hole portion 15 (second hole portion). Specifically, the second thermally conductive portion 13b is formed of a metal mass, i.e., a core material, of a material with high thermal conductivity, such as copper.

In other words, the hole 15 (second hole) in which the second heat conductive portion 13b is disposed is formed inside the first main surface 11a and the second main surface 11b so as not to be exposed to at least one of them. For example, in FIG. 1, the hole 15 (second hole) in which the second heat conductive portion 13b is disposed is formed so as not to be exposed to the first main surface 11a but only to the second main surface 11b, that is, so as to be connected only to the second main surface 11b. As a result, the second heat conductive portion 13b in FIG. 1 is exposed to the second main surface 11b, does not connect to the first main surface 11a, and is disposed so as to be spaced apart from the first main surface 11a in the Z direction.

The hole portion 15 includes a hole portion (first hole portion) that penetrates the substrate body 12 from the first main surface 11a to the second main surface 11b of the substrate 11, and a hole portion (second hole portion) that extends only a part of the substrate body 12 in the Z direction and leads to only either the first main surface 11a or the second main surface 11b. As in FIGS. 1 to 3, the hole portion 15 (first hole portion) that penetrates the substrate body 12 from the first main surface 11a to the second main surface 11b is formed in the center in the X direction in FIG. 4, and is formed to include an area that overlaps with the heat generating component 22 in a plan view. In FIG. 4, only one hole portion 15 (first hole portion) that penetrates the substrate body 12 is formed in the center of the substrate body 12. The first heat conducting portion 13a is inserted inside this hole portion 15 (first hole portion). In contrast, the latter hole portion 15 (second hole portion) that extends only a part of the substrate main body 12 and does not penetrate is formed around the hole portion 15 (first hole portion) into which the first heat conductive portion 13a is inserted in FIG. 4, with a space between the hole portion 15 and the first hole portion 15 in the X direction and the Y direction. In FIG. 4, some of the holes 15 (second hole portion) among the plurality of non-penetrating holes 15 (second hole portion) extend downward in the Z direction from the first main surface 11a. Since these holes 15 (second hole portion) are formed on the upper side in the Z direction in FIG. 4, they will be referred to as upper non-penetrating holes 15 (second hole portion) hereinafter. In FIG. 4, other holes 15 (second hole portion) among the plurality of non-penetrating holes 15 (second hole portion) extend upward in the Z direction from the second main surface 11b. These holes 15 (second holes) are formed on the lower side in the Z direction in FIG. 4, and will hereafter be referred to as lower non-through holes 15 (second holes).

In FIG. 4, the upper non-through hole 15 (second hole) and the lower non-through hole 15 (second hole) overlap each other in a plan view. In FIG. 4, the non-through holes 15 (second hole) are narrower in width in the X direction than the central through hole 15 (first hole). Although not shown, the non-through holes 15 (second hole) may be narrower in width in the Y direction than the central through hole 15 (first hole). In FIG. 4, two rows of non-through holes 15 (second hole) are formed on the left and right sides of the central through hole 15 (first hole), but the number of rows is arbitrary.

Of these multiple non-through holes 15 (second holes), the second heat conductive part 13b is inserted into the lower non-through hole 15 (second hole). As a result, the second heat conductive part 13b as a core material is arranged to communicate with the second main surface 11b. On the other hand, in FIG. 1, the second heat conductive part 13b as a core material is not inserted into the upper non-through hole 15 (second hole) of the multiple non-through holes 15.

In other words, in FIG. 4, the first heat conducting portion 13a and the second heat conducting portion 13b as the heat conducting portion 13 both communicate with the second main surface 11b. On the other hand, the first heat conducting portion 13a communicates with the first main surface 11a, but the second heat conducting portion 13b does not communicate with the first main surface 11a. Therefore, in FIG. 4, the sum of the areas of the portions where the first heat conducting portion 13a and the second heat conducting portion 13b as the heat conducting portion 13 communicate with the second main surface 11b is greater than the sum of the areas of the portions where the first heat conducting portion 13a and the second heat conducting portion 13b as the heat conducting portion 13 communicate with the first main surface 11a.

Among these multiple non-through holes 15, the second heat conductive portion 13b inserted into the lower non-through hole 15 (second hole) and filling the hole 15 is a core material made of a conductive material such as copper. In contrast, inside the upper non-through hole 15 (second hole), a second conductive material such as copper that covers the inner wall of the hole 15 may be formed as the second heat conductive portion instead of the conductive material as the core material. This conductive material is the inner wall conductive film 16. The inner wall conductive film 16 may also be formed on the inner wall surface of the lower non-through hole 15 (second hole) that is filled with the second heat conductive portion 13b as the core material. In FIG. 1, the inner wall conductive film 16 is also formed on the inner wall surface of the lower non-through hole 15 (second hole).

Note that, although not shown here, the second conductive member, which is the second heat conductive portion 13b, may be engaged by screwing to the substrate 11 in the same manner as the first conductive member in FIG. 1. In this case, the second conductive member has a first screw groove formed on its outer circumferential surface. Also, the second conductive member, which is the second heat conductive portion 13b, may be formed of a portion formed inside the hole portion 15 (second hole portion) and a portion protruding to the outside of the hole portion 15 (second hole portion) in the same manner as the first conductive member in FIG. 1. Also, the hole portion 15 (second hole portion) has a second screw groove formed on its inner circumferential surface. The substrate 11 and the second heat conductive portion 13b are engaged by screwing so that the first screw groove and the second screw groove mesh with each other. Furthermore, although not shown here, the second heat conductive portion 13b may have a configuration in which a heat dissipation fin is formed on the surface opposite to the surface facing the heat generating component 22 in the same manner as the first heat conductive portion h in FIG. 2. Furthermore, although not shown here, the second heat conducting portion 13b may be configured in such a way that the heat dissipation member 31 and the second heat conducting portion 13b are fixed together by a fastening member such as a screw, similar to the heat conducting portion 13i in FIG. 3. In more detail, the second heat conducting portion 13b may be fixed together by a fastening member inserted into a hole formed in the heat dissipation member 31 and a hole formed in the second heat conducting portion 13b.

The second heat conductive portion 13b is inserted into a non-through hole portion 15 (second hole portion) that is smaller in dimensions in the Z direction, X direction, and Y direction than the hole portion 15 into which the first heat conductive portion 13a is inserted. For this reason, in FIG. 4, the second heat conductive portion 13b is smaller in dimensions than the first heat conductive portion 13a. However, this is not limited to this, and for example, multiple first heat conductive portions 13a that are approximately the same size as the second heat conductive portion 13b may be inserted into the central hole portion 15 (first hole portion).

In FIG. 4, the size of the non-through holes 15 (second holes) arranged in multiple rows in the X direction has the following characteristics. That is, as the center hole 15 (first hole) is approached, the lower non-through holes 15 (second holes) extend longer in the Z direction, and the upper non-through holes 15 (second holes) extend shorter in the Z direction. In this way, more space can be secured for arranging the inner layer wiring 14. However, this is not limited to this embodiment. As long as the arrangement space for the inner layer wiring 14 can be secured, for example, among the non-through holes 15 (second holes) in each row, the upper non-through holes 15 (second holes) and the lower non-through holes 15 (second holes) that overlap each other in a plan view may have approximately the same length extending in the Z direction.

Also, as shown in FIG. 4, the total number of core materials of the heat conductive portion 13 that connects to the second main surface 11b side may be greater than the total number of core materials of the heat conductive portion 13 that connects to the first main surface 11a side. Specifically, in FIG. 4, there is only one first heat conductive portion 13a that connects to the first main surface 11a. In contrast, in FIG. 4, there are a total of five core materials that connect to the second main surface 11b, including one first heat conductive portion 13a and four second heat conductive portions 13b.

In FIG. 4, the inner layer wiring 14 is arranged to connect the first heat conductive portion 13a and the second heat conductive portion 13b. Here, the inner layer wiring 14 is meant to thermally and electrically connect the first heat conductive portion 13a and the second heat conductive portion 13b.

Specifically, for example, a first heat conductive portion 13a as a core material and a second heat conductive portion 13b as a core material are filled in a hole 15 formed in the substrate 11. As described later, these holes 15 are formed as portions of the resin substrate body 12 and the thin film pattern of copper or the like formed thereon to become the inner layer wiring 14, where these portions are missing. Therefore, the inner layer wiring 14 is exposed on at least a part of the inner wall surface of the hole 15. A heat conductive portion 13 of a conductive material as a core material is inserted into this hole 15. At least a part of the surface of the heat conductive portion 13 contacts the exposed part of the inner layer wiring 14 that forms the inner wall surface of the hole 15. As a result, the first heat conductive portion 13a and the second heat conductive portion 13b are connected to the inner layer wiring 14 at the portion where the heat conductive portion 13 in the hole 15 and the inner layer wiring 14 exposed on the inner wall surface of the hole 15 contact each other. These connections are made thermally and electrically.

However, the heat conductive portion 13 and the inner wiring 14 in the hole 15 may be connected to each other by sandwiching another conductive member, such as the inner wall conductive film 16 as a plating film on the inner wall surface, or a thin resin between them. Even in this case, the heat conductive portion 13 and the inner wiring 14 are at least thermally connected through the inner wall conductive film 16 and a member such as a thin resin between them. In other words, heat can be conducted between the heat conductive portion 13 and the inner wiring 14. Therefore, in this embodiment, the heat conductive portion 13, i.e., the first heat conductive portion 13a and the second heat conductive portion 13b, and the inner wiring 14 are defined as being "connected" including such a case. In addition, the first heat conductive portion 13a and the second heat conductive portion 13b are at least thermally connected through the inner wall conductive film 16 in the hole 15 into which the first heat conductive portion 13a is inserted and the inner wall conductive film 16 in the hole 15 into which the second heat conductive portion 13b is inserted. For this reason, the inner layer wiring 14 is arranged so as to connect the first heat conducting portion 13a and the second heat conducting portion 13b, i.e., at least thermally connect them, for example, via the inner wall conductive film 16. However, it is more preferable that the heat conducting portion 13 and the inner layer wiring 14 are electrically connected, for example, via the inner wall conductive film 16. It is also more preferable that the inner layer wiring 14 is electrically connected between the first heat conducting portion 13a and the second heat conducting portion 13b via the inner wall conductive film 16.

In addition, directly above the upper non-penetrating hole 15 (second hole), a plating film 17a is formed, which is, for example, of the same material and thickness as the surface wiring 17. The plating film 17a is, for example, a thin copper film formed by plating. The plating film 17a is a conductive film formed so as to compensate for the portion of the inner wiring 14 that was removed by the formation of the hole 15. Therefore, the plating film 17a is formed so as to block the hole 15 from above in the Z direction.

The second heat conducting portion 13b is connected to the inner layer wiring 14 either directly or via the inner wall conductive film 16 on the inner wall surface of the hole 15 in which it is placed. In other words, the first heat conducting portion 13a is at least thermally connected to the second heat conducting portion 13b via the inner layer wiring 14. Therefore, heat transferred to the first heat conducting portion 13a can be transferred to the second heat conducting portion 13b via the inner layer wiring 14. The second heat conducting portion 13b can dissipate heat to the heat dissipation member 31 directly below it, just like the first heat conducting portion 13a.

Figure 5 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a second example of the fourth embodiment. Referring to Figure 5, in the heat dissipation device 102 according to the second example of the present embodiment, a plurality of holes 15 (first holes) are formed at intervals in the center of the substrate body 12. Although three holes 15 (first holes) are shown as an example in Figure 5, the number of holes 15 is not limited to this. The first heat conductive parts 13a are inserted inside these holes 15. Therefore, each first heat conductive part 13a in Figure 5 has smaller dimensions in the X and Y directions than each first heat conductive part 13a in Figure 4.

Figure 6 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a third example of embodiment 4. Referring to Figure 6, in the heat dissipation device 103 of the third example of this embodiment, the upper non-through hole 15 (second hole) closest to the central through hole 15 has a lower non-through hole 15 (second hole) so as to overlap with it in a plan view, as in the other examples described above. The lower non-through hole 15 (second hole) is filled with the second heat conductive portion 13b. However, the upper non-through hole 15 (second hole) on the outer side does not overlap with the lower non-through hole 15 (second hole) in a plan view. And further outside the upper non-through hole 15 (second hole), it has a lower non-through hole 15 (second hole). The inside of this lower non-through hole 15 (second hole) is not filled with the second heat conductive portion 13b. The outer upper non-through hole 15 (second hole) and the lower non-through hole 15 (second hole) are connected by the inner layer wiring 14.

In the heat dissipation device 103, a non-conductive heat dissipation sheet 33 is disposed between the substrate 11 and the heat dissipation member 31. The non-conductive heat dissipation sheet 33 is made of an insulating material with high thermal conductivity, such as epoxy resin. The non-conductive heat dissipation sheet 33 is a flat member. This is the second main surface 11b side of the substrate 11, and is joined to the upper side of the heat dissipation member 31 in the Z direction.

There are cases where it is desired to avoid connecting the upper non-through hole 15 (second hole) to the heat dissipation member 31, which also functions as a frame ground. However, if the hole 15 is made non-through for that purpose, the hole 15 does not reach the second main surface 11b, and therefore the heat dissipation performance is inferior. Therefore, as shown in FIG. 3, a non-conductive heat dissipation sheet 33 is placed between the board 11 and the heat dissipation member 31. As a result, as shown in FIG. 3, the upper non-through hole 15 (second hole) and the lower non-through hole 15 (second hole) are electrically connected by the inner layer wiring 14 or the like, and an integrated structure is obtained. The integrated structure enables heat dissipation from the mounted component 21 to the heat dissipation member 31 below, thereby improving the heat dissipation function of the entire heat dissipation device 103.

In the manufacturing process of the heat dissipation devices 101, 102, and 103 shown in Figures 4 to 6, the following steps are further performed in the preparation step (S10) in the manufacturing process of the heat dissipation devices 100a, 100b, and 100c shown in Figures 1 to 3. After a wiring pattern, for example of copper, is formed on one or both main surfaces of each of the multiple plate materials, a via is formed in each of the multiple plate materials, penetrating the plate materials from one main surface to the other main surface on the opposite side. It is preferable that this via is formed so that, for example, when one plate material and another plate material among the multiple plate materials are overlapped, the via of the one plate material and the via of the other plate material overlap at the same position. In particular, when the multiple plate materials are overlapped, it is preferable that the above-mentioned vias overlap each other to form a non-penetrating hole portion 15 (second hole portion) of the substrate 11 shown in any one of Figures 1 to 3. In addition, a thin copper film is formed on the inner wall surface of the via as a film to be the inner wall conductive film 16, for example, by a plating process. In the next lamination step (S20), the vias are connected to each other to form non-through holes 15 (second holes).

When the substrate 11 is formed to the required thickness, a hole 15 (first hole) is formed in the substrate 11 so as to penetrate the entire substrate body 12 from the first main surface 11a to the second main surface 11b in the hole drilling process (S40). A thin copper film may also be formed as an inner wall conductive film 16 on the inner wall surface of the hole 15, for example, by a plating process. If the core material of the second heat conducting portion 13b is configured to have a first screw groove, a second screw groove is formed on the inner peripheral surface, which is the inner wall surface of the hole 15, or on the inner wall conductive film 16 covering the inner peripheral surface.

Then, among the holes 15 that do not penetrate the substrate 11, the core material of the second heat conductive portion 13b is inserted, for example, by a press-in process into the hole 15 that is formed to lead to the second main surface 11b. If the core material of the second heat conductive portion 13b is configured to have a first screw groove, the first screw groove is formed on the outer peripheral surface of the second conductive member of the second heat conductive portion 13b, similar to the first heat conductive portion 13b. At this time, the substrate 11 and the second heat conductive portion 13b are engaged by screwing so that the first screw groove formed in the second conductive member and the second screw groove formed in the hole 15 engage with each other. The second heat conductive portion 13b is a core material that has been shaped in advance to become a metal lump. After the core material is inserted, a heat treatment process and a chemical process may be performed as necessary.

After that, if necessary, a hole-filling resin may be filled into the gap between the inner wall surface of the hole 15 of the substrate body 12 and the core material of the thermally conductive portion 13 filled therein. Alternatively, the thermally conductive portion 13 inserted into the hole 15 may be partially crimped by a press-fitting process. In this way, the thermally conductive portion 13 is fixed in the hole 15 without the need for a resin material.

Next, the effects of the fourth embodiment, which are obtained in addition to the effects of the above-mentioned embodiments, will be described. The heat dissipation device according to the present disclosure includes a substrate 11 and a heat generating component 22. The heat generating component 22 is disposed on a first main surface 11a of the substrate 11. The substrate 11 includes a heat conducting portion 13 and an inner layer wiring 14. The heat conducting portion 13 transmits heat generated by the heat generating component 22. The inner layer wiring 14 is formed so as to be connected to the heat conducting portion 13 within the substrate 11. The heat conducting portion 13 has a first heat conducting portion 13a. The first heat conducting portion 13a includes an area overlapping with the heat generating component 22 in a plan view, and penetrates the substrate 11 from the first main surface 11a to the second main surface 11b opposite to the first main surface 11a. The first heat conducting portion 13a is formed by a first conductive member filled in a hole portion 15 (inside a first hole portion) formed in the substrate 11. The first conductive member has a first thread groove formed on its outer circumferential surface. The hole 15 (first hole) formed in the substrate 11 has a second thread groove formed on its inner circumferential surface. The first thread groove and the second thread groove are engaged with each other.

The heat conducting portion 13 also has a second heat conducting portion 13b. The second heat conducting portion 13b is arranged around the first heat conducting portion 13a with a gap between it and the first heat conducting portion 13a, and is arranged with a gap between it and at least one of the first main surface 11a and the second main surface 11b. The heat of the heat-generating component 22 is directly transmitted to the first heat conducting portion 13a, which includes an area overlapping with the heat-generating component 22 in a plan view. The heat conducting portion 13 and the inner layer wiring 14 are arranged so as to be connected, particularly thermally connected. Therefore, the heat transmitted to the first heat conducting portion 13a is transmitted to the inner layer wiring 14, and is easily transmitted from there to the second heat conducting portion 13b. This allows the heat of the heat-generating component 22 to be dispersed not only to the first heat conducting portion 13a but also to the surrounding second heat conducting portion 13b. Therefore, heat can be dissipated from the first heat conductive portion 13a and the second heat conductive portion 13b to the outside, such as the heat dissipation device 101. In other words, the thermal resistance of the heat dissipation route can be reduced compared to when only the first heat conductive portion 13a is provided. As a result, high heat dissipation performance can be achieved in the entire heat dissipation devices 101 to 103.

Heat from the heat-generating component 22 is transferred with high heat dissipation to the first heat conductive portion 13a directly below it. However, if there was only one route for transferring heat from there to the heat dissipation member 31 directly below, the heat dissipation function may still be insufficient. Therefore, an additional route for transferring heat from the first heat conductive portion 13a to the second heat conductive portion 13b is provided via the inner layer wiring 14 that is thermally connected to the first heat conductive portion 13a. As a result, the number of heat dissipation routes from the heat-generating component 22 to the heat dissipation member 31 is increased in the heat dissipation devices 101 to 103, achieving even higher heat dissipation performance.

The second heat conducting portion 13b is arranged, for example, at a distance from the first main surface 11a. Conversely, the second heat conducting portion 13b is arranged, for example, on the second main surface 11b side. This can further enhance the heat dissipation function of the second heat conducting portion 13b to the heat dissipation member 31 side, particularly on the second main surface 11b side of the substrate 11 opposite the first main surface 11a side on which the heat generating component 22 is arranged.

The second heat conducting portion 13b is arranged, for example, at a distance from the first main surface 11a. This allows for an increased space for routing the power supply and control signals of the mounted components 21, particularly in the area close to the first main surface 11a in the substrate 11. The number of power supplies and control signals of the mounted components 21 to be arranged around the first heat conducting portion 13a in the substrate 11 is restricted by the power supplies and control signals of the mounted components 21 arranged around the first heat conducting portion 13a. The area in the substrate 11 particularly close to the first main surface 11a is set as the arrangement area for the power supply and control signals. As a result, the area in the substrate 11 particularly close to the second main surface 11b, which is the opposite side to the side where the heat generating components 22 are arranged, can be used as the area where the second heat conducting portion 13b is arranged and the heat of the heat generating components 22 is released from the second heat conducting portion 13b to the outside of the heat dissipation device.

From the viewpoint of achieving the above effects, in the heat dissipation device, it is preferable that the second heat conductive portion 13b is arranged so as to be connected to the second main surface 11b. In the heat dissipation device, it is preferable that the sum of the areas of the portions of the first heat conductive portion 13a and the second heat conductive portion 13b as the heat conductive portion 13 that are connected to the second main surface 11b is greater than the sum of the areas of the portions of the first heat conductive portion 13a and the second heat conductive portion 13b as the heat conductive portion 13 that are connected to the first main surface 11a. In this way, the heat conductive portions 13 are arranged on the second main surface 11b of the substrate 11 in a larger area or in greater numbers than on the first main surface 11a. Therefore, the heat of the heat generating component 22 can be dissipated from the heat dissipation member 31 to the outside of the substrate 11 more efficiently on the second main surface 11b side.

In the above heat dissipation device, the second heat conductive portion 13b is preferably formed from a core material as a conductive member filled in the hole 15 formed in the substrate 11. In this way, the heat dissipation function of the second heat conductive portion 13b can be further improved.

However, in the above heat dissipation device, the second heat conduction section may be formed by an inner wall conductive film 16 as a conductive member that covers the inner wall of a hole 15 formed in the substrate 11. In this case, no core material or the like is placed inside the inner wall conductive film 16 in the hole 15, and it is hollow. However, even in this case, the thermal conductivity of the inner wall conductive film 16 ensures a minimum level of thermal conductivity for the second heat conduction section. Because no core material is provided, such a second heat conduction section can reduce manufacturing costs by reducing material costs.

In the above heat dissipation device, the inner layer wiring 14 is preferably arranged to connect the first heat conductive portion 13a and the second heat conductive portion 13b. For example, the resin material constituting the board body 12 has difficulty in sufficiently transmitting the heat transmitted from the heat generating component 22 to the first heat conductive portion 13a directly below it to the second heat conductive portion 13b. Therefore, the first heat conductive portion 13a and the second heat conductive portion 13b are connected by the inner layer wiring 14. This allows the heat of the first heat conductive portion 13a to be easily transmitted to the second heat conductive portion 13b via the inner layer wiring 14. In this way, the heat of the heat generating component 22 can be dissipated to the outside not only from the first heat conductive portion 13a but also from the second heat conductive portion 13b.

Embodiment 5.
Fig. 8 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to embodiment 5. Referring to Fig. 8, this embodiment has a third heat conductive portion 13c. Specifically, in heat dissipation device 201 according to embodiment 5 shown in Fig. 5, third heat conductive portion 13c as heat conductive portion 13 is arranged to be sandwiched between heat generating component 22 and first heat conductive portion 13a. Third heat conductive portion 13c is arranged to include an area overlapping heat generating component 22 in plan view. In Fig. 5, first heat conductive portion 13a entirely overlaps heat generating component 22 in plan view.

The third heat conductive portion 13c is, for example, a plate having a rectangular planar shape. The third heat conductive portion 13c is formed from a metal block of a material with high thermal conductivity, such as copper.

The third heat conductive portion 13c is disposed at approximately the same position as the solder ball 32 in the Z direction. The third heat conductive portion 13c is also joined to the plating film 17a that covers the upper part of the hole 15 into which the first heat conductive portion 13c is inserted, by a reflow layer 34. The reflow layer 34 refers to a layer that is joined by a reflow process described below. The third heat conductive portion 13c is also joined to the bottom surface of the package 23 by a bonding layer 35. This bonding layer 35 is made of a material with high thermal conductivity, in particular a material that is more conductive than the solder ball 32.

Next, a method for joining the heat dissipation device 201 of FIG. 8, particularly the substrate 11 and the mounted component 21, will be described with reference to FIG. 9. FIG. 9 is a schematic cross-sectional view showing a joining process between the substrate and the mounted component in the manufacturing process of the heat dissipation device of FIG. 8. Referring to FIG. 9, reflow solder 34a is applied onto the surface wiring 17 and plating film 17a on the first main surface 11a of the substrate 11. The reflow solder 34a is a paste-like solder material used for joining by the reflow process described below. However, the reflow solder 34a is not limited to a solder material, and other paste-like conductive materials that can be joined by the reflow process may be used.

As shown in FIG. 9, prior to bonding of the substrate 11 and the mounted component 21, the third heat conductive portion 13c is bonded by a bonding layer 35 at a position of the mounted component 21 where it overlaps, for example, the heat generating component 22 in a plan view. The third heat conductive portion 13c is bonded to the bottom surface of the package 23. The bonding layer 35 used for this bonding is made of a material that is more conductive than the solder balls 32.

Then, as shown in FIG. 9, the mounted component 21 to which the third heat conductive portion 13c and the solder ball 32 are joined is placed on the board 11 to which reflow solder 34a has been applied. The reflow solder 34a is applied to the surface wiring 17 and plating film 17a of the board 11 in an area that should overlap the solder ball 32 or the third heat conductive portion 13c in a planar view. With the mounted component 21 placed on the board 11, a commonly known reflow process is performed. As a result, the reflow solder 34a becomes a reflow layer 34, and the board 11 and the mounted component 21 are joined.

Next, the effects of this embodiment will be described. For example, if the package is a BGA package, the board and the mounted components are connected by solder balls. Therefore, the area of the region that can be thermally connected between the board and the mounted components is limited by the amount and surface area of the solder balls. Therefore, if the amount and surface area of the solder balls are insufficient, the thermal resistance between the board and the mounted components will be large. Therefore, it is desirable to minimize the thermal resistance between the two.

In order to reduce thermal resistance, solder balls may be made of highly thermally conductive bonding materials, such as a solder material containing a metal core or silver paste. However, bonding materials with high thermal conductivity are expensive. For this reason, using only solder balls made of the above materials for the entire heat dissipation device will increase costs. In order to reduce material costs, it is preferable to selectively use the above materials only for solder balls in areas of the heat dissipation device that require particularly high heat dissipation properties.

Therefore, in the heat dissipation device according to the disclosure of this embodiment, the third heat conductive portion 13c is sandwiched between the heat generating component 22 and the first heat conductive portion 13a. In other words, the third heat conductive portion 13c with high thermal conductivity is arranged at least directly below the heat generating component 22, i.e., in the area where the amount of heat dissipation is large and overlaps with the heat generating component 22 in a plan view. For this reason, the solder balls 32 arranged in the area other than the arrangement area of the third heat conductive portion 13c can be made of a cheaper material with a lower thermal conductivity than the material used in embodiment 4. Even in this case, by arranging at least the third heat conductive portion 13c, high heat dissipation performance can be ensured in the entire heat dissipation device 201.

In addition, if the third heat conductive portion 13c has a rectangular plate shape, the joint between it and the first heat conductive portion 13a does not need to be spherical like the solder ball 32. In other words, the degree of freedom in the shape of the joint increases. Therefore, by giving the joint a shape with low thermal resistance, the thermal resistance of the joint can be reduced. Therefore, the third heat conductive portion 13c can reduce the thermal resistance of the joint between it and the substrate 11. Therefore, high heat dissipation performance can be ensured throughout the heat dissipation device 201.

Embodiment 6.
Fig. 10 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a first example of the sixth embodiment. Referring to Fig. 10, a heat dissipation device 301 according to the first example of the present embodiment has almost the same configuration as the heat dissipation device 101, but a first heat conduction part 13ad is arranged instead of the first heat conduction part 13a. The first heat conduction part 13ad as a core material is made of copper molybdenum (CuMo). Thus, the first heat conduction part 13ad in the present embodiment contains copper molybdenum.

Figure 11 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a second example of the sixth embodiment. Referring to Figure 11, the heat dissipation device 302 according to the second example of the present embodiment has almost the same configuration as the heat dissipation device 102, but instead of the first thermal conductive portion 13a, a first thermal conductive portion 13ad made of copper molybdenum is arranged. Figure 12 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a third example of the sixth embodiment. Referring to Figure 12, the heat dissipation device 303 according to the third example of the present embodiment has almost the same configuration as the heat dissipation device 201, but instead of the first thermal conductive portion 13a, a first thermal conductive portion 13ad made of copper molybdenum is arranged.

Next, the effect of the sixth embodiment will be described. By using the first thermal conductive portion 13ad containing copper molybdenum as shown in Figures 10 to 12, it is possible to further improve the heat dissipation performance compared to the first thermal conductive portion 13a made of copper.

In the heat dissipation devices 301 to 303 in Figs. 10 to 12, the core material of the second heat conductive portion 13b may be made of copper as in the fourth and fifth embodiments. However, the second heat conductive portion 13b of the heat dissipation devices 301 to 303 may also contain copper molybdenum or be made of copper molybdenum as in the first heat conductive portion 13ad. Fig. 13 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a fourth example of the sixth embodiment. Referring to Fig. 13, the heat dissipation device 304 of the fourth example of the present embodiment has almost the same configuration as the heat dissipation device 301, but the core material of the second heat conductive portion 13b is not arranged in the lower non-through hole portion 15 (second hole portion). Fig. 14 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a fifth example of the sixth embodiment. Referring to FIG. 14, the heat dissipation device 305 of the fifth example of this embodiment has almost the same configuration as the heat dissipation device 302, but the core material of the second heat conductive portion 13b is not arranged in the lower non-through hole portion 15 (second hole portion). Since high heat dissipation is ensured by the first heat conductive portion 13ad, the second heat conductive portion around it may be configured as shown in FIGS. 13 and 14, which is only the inner wall conductive film 16 having only the minimum thermal conductivity. Since no core material is provided, the inner wall conductive film 16, which is the second heat conductive portion in the lower non-through hole portion 15 (second hole portion), can reduce the manufacturing cost by reducing the material cost. Also, in FIG. 13 and FIG. 14, the first heat conductive portion 13a similar to the fourth and fifth embodiments may be used instead of the first heat conductive portion 13ad.

Embodiment 7.
FIG. 15 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a first example of the seventh embodiment. The first heat conduction portion 13e of the heat dissipation device 401 is different in shape from the first heat conduction portion 13h or the first heat conduction portion 13i. Here, the first heat conduction portion 13e is different in shape from the first heat conduction portion 13h, but the first heat conduction portion 13i may have the same configuration. With reference to FIG. 15, the heat dissipation device 401 of the first example of this embodiment does not have a non-through hole portion 15 (second hole portion), and only the hole portion 15 (first hole portion) is formed in the substrate 11 from the first main surface 11a to the second main surface 11b. This hole portion 15 is formed in the center of the X direction in FIG. 15, and is formed so as to include an area overlapping with the heat generating component 22 in a plan view. In FIG. 1, such a substrate main body 12 has only one hole portion 15 (first hole portion) formed in the center of the substrate main body 12. Hole 15 has a width in a direction along the main surface and a cross-sectional area along an XY plane intersecting with the Z direction that extends therein that gradually increases from first main surface 11a to second main surface 11b.

That is, the inner wall surface of the hole 15 extending from the first main surface 11a to the second main surface 11b extends at an angle with respect to the Z direction. In other words, in the cross-sectional view of FIG. 15, the inner wall surface of the hole 15 extends in a tapered shape.

The inside of the hole 15 is filled with a first heat conducting portion 13e as the heat conducting portion 13. The first heat conducting portion 13e is arranged so as to fill almost the entire inside of the hole 15, similar to the first heat conducting portion 13a of the first embodiment. That is, the first heat conducting portion 13e is arranged so as to penetrate the substrate 11, particularly the substrate body 12, from the first main surface 11a to the second main surface 11b. The first heat conducting portion 13e includes an area that overlaps with the heat generating component 22 in a planar view. However, since the first heat conducting portion 13e becomes larger toward the bottom in the Z direction, the outside of the first heat conducting portion 13e does not overlap with the heat generating component 22 in a planar view, particularly in the area on the second main surface 11b side. The first heat conducting portion 13e is a core material made of a material with high thermal conductivity such as copper, having a tapered cross-sectional shape similar to the hole 15.

The first heat conducting portion 13e has a heat dissipation fin formed on the surface opposite to the surface facing the heat generating component 22, similar to the first heat conducting portion h in FIG. 2. More specifically, the first conductive member that is the first heat conducting portion 13e is formed of a portion formed inside the hole portion 15 (first hole portion) and a portion protruding to the outside of the hole portion 15 (first hole portion), similar to the first heat conducting portion 13h. A heat dissipation fin is formed on this portion protruding to the outside. Although not shown here, the first heat conducting portion 13e may be configured in such a way that the heat dissipation member 31 and the first heat conducting portion 13e are fixed by a fastening member such as a screw, similar to the heat conducting portion 13i in FIG. 3. More specifically, the first heat conducting portion 13e may be configured in such a way that the heat dissipation member 31 and the first heat conducting portion 13e are fixed by a fastening member inserted into the hole portion formed in the heat conducting portion 31 and the hole portion formed in the first heat conducting portion 13e.

The inner layer wiring 14 is partially removed when the hole 15 is formed, so that it is exposed on at least a portion of the inner wall surface of the hole 15. However, an inner wall conductive film 16 may be formed on the inner wall surface. In any case, the first heat conductive portion 13e and the inner layer wiring 14 are at least thermally connected. It is more preferable that the first heat conductive portion 13e and the inner layer wiring 14 are electrically connected.

In the heat dissipation device 401, similar to the heat dissipation device 201, the third heat conductive portion 13c as the heat conductive portion 13 is arranged to be sandwiched between the heat generating component 22 and the first heat conductive portion 13a. However, the heat dissipation device 401 does not have the third heat conductive portion 13c, and the substrate 11 and the mounted component 21 may be connected by the solder balls 32 even in the area where the third heat conductive portion 13c is arranged.

Figure 16 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a second example of the seventh embodiment. With reference to Figure 16, the heat dissipation device 402 according to the second example of the present embodiment differs from the heat dissipation device 401 in the following respects. The substrate 11 of the heat dissipation device 402 has a non-through hole 15 (second hole) formed on the upper side. In addition, the hole 15 (first hole) of the substrate 11 from the first main surface 11a to the second main surface 11b has a width in a direction along the main surface and a cross-sectional area along the XY plane intersecting the Z direction in which it extends that gradually increase from the first main surface 11a to the second main surface 11b.

In other words, the inner wall surface of the hole 15 extending from the first main surface 11a to the second main surface 11b extends so as to periodically have a portion extending in the Z direction and a portion bending from that portion to extend along the X direction and the Y direction. In other words, in the cross-sectional view of FIG. 16, the inner wall surface of the hole 15 extends in a stepped manner.

The inside of the hole 15 is filled with a first heat conductive portion 13f as the heat conductive portion 13. The first heat conductive portion 13f is a core material such as copper. The filling manner of the first heat conductive portion 13f into the hole 15 is similar to the filling manner of the first heat conductive portion 13e into the hole 15 in the heat dissipation device 402.

The conductive member, which is the first heat conducting portion 13f, is engaged with the substrate 11 by screwing it in the same manner as the first conductive member in FIG. 1. More specifically, the conductive member, which is the first heat conducting portion 13f, has a first screw groove formed on its outer peripheral surface. The hole portion 15 (second hole portion) has a second screw groove formed on its inner peripheral surface. The substrate 11 and the first heat conducting portion 13f are engaged with each other by screwing so that the first screw groove and the second screw groove mesh with each other. As with the heat dissipation device 401, the first heat conducting portion 13f may be configured to be inserted into the hole portion 15 by press-fitting without having the first screw groove formed, if necessary. Furthermore, although not shown here, the first heat conducting portion 13f may be configured to be fixed between the heat dissipation member 31 and the first heat conducting portion 13e by a fastening member such as a screw, as with the heat conducting portion 13i in FIG. 3. Specifically, the heat dissipation member 31 may be fixed by a fastening member inserted into a hole formed in the first heat conductive portion 13f. The first heat conductive portion 13f and the inner layer wiring 14 are at least thermally connected.

That is, the first heat conducting portion 13f has a stepped cross-sectional shape. The first heat conducting portion 13f has a width in the X direction that allows it to face the upper non-through hole portion 15 (second hole portion) located directly above it in the Z direction. The hole portion 15 closest to the first heat conducting portion 13f among the multiple non-through holes 15 (second hole portion) faces the second region of the first heat conducting portion 13f, which is one step wider than the narrow first region of the first heat conducting portion 13f that leads to the first main surface 11a, in the Z direction. The hole portion 15 farthest from the first heat conducting portion 13f among the multiple non-through holes 15 (second hole portion) faces the third region of the first heat conducting portion 13f, which is one step wider than the second region, in the Z direction. In this way, it is preferable that the width of the first heat conductive portion 13f in the X direction be gradually increased in accordance with the position of the non-through hole portion 15 (second hole portion) in the X direction so as to face it.

Next, the insertion process and bonding process of the first heat conductive part 13e into the hole 15 of the substrate 11 bonded to the mounted component 21 of the heat dissipation device 401 of FIG. 15 will be described with reference to FIG. 17 and FIG. 18. FIG. 17 is a schematic cross-sectional view showing the insertion process of the heat conductive part into the hole of the substrate as the first process of the manufacturing process of the heat dissipation device of FIG. 15. Referring to FIG. 17, the substrate 11 and the mounted component 21 are bonded via the solder ball 32 by the reflow process similar to the process of FIG. 9. At this point, the inside of the hole 15 formed in the substrate 11 is hollow. After the bonding, the core material of the first heat conductive part 13e, the uppermost surface of which is coated with, for example, paste-like low-temperature solder 36a, is inserted into the hole 15.

18 is a schematic cross-sectional view showing the bonding process of the heat conductive portion as the second process of the manufacturing process of the heat dissipation device of FIG. 15. Referring to FIG. 18, for example, a reflow process is performed again using low-temperature solder 36a. As a result, the low-temperature solder 36a becomes a low-temperature solder layer 36, and the first heat conductive portion 13e is bonded to the lower surface of the third heat conductive portion 13c. As a result, the first heat conductive portion 13e is filled in the hole portion 15 of the substrate 11. The reason why the low-temperature solder 36a is used here is to prevent the occurrence of defects such as the reflow solder 34a used for bonding in the previous reflow process being melted again during the second reflow process. In other words, the low-temperature solder 36a means a solder material with a lower melting point than the reflow solder 34a used in the previous reflow process. However, the low-temperature solder 36a is not limited to a solder material, and any material can be used as long as it has a lower melting point than the reflow solder 34a.

Although detailed explanation is omitted, the insertion process and bonding process of the first heat conductive portion 13f in the heat dissipation device 402 in FIG. 16 are also performed by basically the same process as in FIG. 17 and FIG. 18.

Next, the effects of this embodiment will be described. The heat dissipation device according to the disclosure of this embodiment includes a substrate 11 and a heat generating component 22. The heat generating component 22 is disposed on a first main surface 11a of the substrate 11. The substrate 11 includes a heat conducting portion 13 and an inner layer wiring 14. The heat conducting portions 13e and 13f transmit heat generated by the heat generating component 22. The inner layer wiring 14 is formed so as to be connected to the heat conducting portions 13e and 13f within the substrate 11. The heat conducting portions 13e and 13f include an area that overlaps with the heat generating component 22 in a plan view, and penetrate the substrate 11 from the first main surface 11a to the second main surface 11b opposite the first main surface 11a. The thermally conductive portions 13e and 13f have a larger width along the main surface of the substrate 11 and a larger cross-sectional area in a plane along a direction intersecting the extension direction of the thermally conductive portions 13e and 13f on the second main surface 11b side than on the first main surface 11a side.

As a result, similar to embodiment 4, the area of the portion where heat conduction portions 13e, 13f connect to second main surface 11b is larger than the area of the portion where heat conduction portions 13e, 13f connect to first main surface 11a. Therefore, similar to embodiment 4, the heat of heat-generating component 22 can be dissipated to the outside of substrate 11 more efficiently on the second main surface 11b side.

In addition, in the manufacturing process of the heat dissipation devices 401, 402, if the third heat conductive portion 13c is particularly large, it may not be possible to store it between the substrate 11 and the mounted component 21. In such a case, as in the process of Figures 17 and 18, after the mounted component 21 is mounted on the substrate 11, the heat conductive portions 13e, 13f are inserted into the hole 15 (first hole) of the substrate 11 and joined by low-temperature solder. In this way, the heat dissipation devices 401, 402 having the configuration of Figures 15 and 16 can be provided with high quality.

Embodiment 8.
FIG. 19 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a first example of the eighth embodiment. Referring to FIG. 19, a heat dissipation device 501 according to the first example of the present embodiment has almost the same configuration as the heat dissipation device 100a, but a first heat conduction part 13ad is arranged instead of the first heat conduction part 13a. The first heat conduction part 13ad as a core material is made of copper molybdenum (CuMo). Thus, the first heat conduction part 13ad in the present embodiment contains copper molybdenum. Here, the first heat conduction part 13ad is made of the first heat conduction part 13a of the heat dissipation device 100a, but the first heat conduction part 13ad may be made of the first heat conduction part 13h or the first heat conduction part 13i, which is made of copper molybdenum (CuMo).

The heat dissipation device 501 does not have a non-through hole 15 (second hole), and only the hole 15 (first hole) is formed in the substrate 11 from the first main surface 11a to the second main surface 11b. This hole 15 is formed to include an area overlapping with the heat generating component 22 in a planar view, similar to the hole 15 into which the first heat conducting part 13a of the heat dissipation device 101 is inserted. In FIG. 19, the entire area inside this hole 22 is arranged in an area overlapping with the heat generating component 22 in a planar view. The first heat conducting part 13ad is arranged as the heat conducting part 13 so as to fill almost the entire inside of this hole 15. That is, the core material of the first heat conducting part 13ad, which contains copper molybdenum or is made of copper molybdenum, is arranged in the hole 15 formed in the substrate 11 in the manner shown in FIG. 19. The first heat conducting portion 13ad is arranged to penetrate the substrate 11, particularly the substrate body 12, from the first main surface 11a to the second main surface 11b. The first heat conducting portion 13e includes an area that overlaps with the heat generating component 22 in a plan view.

In the substrate 11, the first heat conductive portion 13ad and the inner layer wiring 14 are at least thermally connected. It is more preferable that the first heat conductive portion 13ad and the inner layer wiring 14 are electrically connected.

Figure 20 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a second example of the eighth embodiment. With reference to Figure 20, a heat dissipation device 502 according to the second example of the present embodiment differs from heat dissipation device 501 in that solder balls 32 are not disposed in the region between the substrate 11 and the mounted component 21 directly above the first thermally conductive portion 13ad.

Next, the effects of the heat dissipation devices 501 and 502 will be described. These heat dissipation devices include a substrate 11 and a heat generating component 22. The heat generating component 22 is disposed on the first main surface 11a of the substrate 11. The substrate 11 includes a heat conducting portion 13ad and an inner layer wiring 14. The heat conducting portion 13ad transmits heat generated by the heat generating component 22. The inner layer wiring 14 is formed so as to be connected to the heat conducting portion 13ad within the substrate 11. The heat conducting portion 13ad includes an area that overlaps with the heat generating component 22 in a plan view, and penetrates the substrate 11 from the first main surface 11a to the second main surface 11b opposite the first main surface 11a. The first heat conducting portion 13ad includes copper molybdenum.

In this way, as in the sixth embodiment, the first heat conductive portion 13ad containing copper molybdenum provides higher heat dissipation than copper. Therefore, even if the solder ball 32 directly below the heat generating component 22 is omitted as in the heat dissipation device 502 of FIG. 20, heat dissipation from the heat generating component 22 to the heat conductive portion 13ad directly below it can be ensured.

Figure 21 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a third example of the eighth embodiment. Referring to Figure 21, a heat dissipation device 503 according to the third example of the present embodiment differs from heat dissipation device 501 in that the hole 15 does not penetrate the substrate 11, but only connects to the first main surface 11a. Therefore, the first thermally conductive portion 13gd filled in the hole 15 also does not penetrate the substrate 11, but only connects to the first main surface 11a. The first thermally conductive portion 13gd is a core material containing or made of copper molybdenum.

Even if the structure shown in FIG. 21 is used, the heat dissipation properties of the first heat conductive portion 13gd containing copper molybdenum are very high. Therefore, the heat dissipation function from the heat generating component 22 to the first heat conductive portion 13gd and the heat dissipation member 31 below it can be ensured to a certain extent. This is because the thermal conductivity of the first heat conductive portion 13gd is high.

Figure 22 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a fourth example of the eighth embodiment. With reference to Figure 22, in the heat dissipation device 504 of the fourth example of this embodiment, the hole 15 is formed in a stepped shape like the heat dissipation device 402, as compared to the heat dissipation device 501. However, the stepped shape of the hole 15 is simpler than that of the heat dissipation device 402. While the heat dissipation device 402 has a three-step stepped shape, the heat dissipation device 504 has a two-step stepped shape. As in the other examples, the core material of the first heat conduction part 13fd containing copper molybdenum is arranged in the hole 15. With the configuration of Figure 22, the high thermal conductivity of the first heat conduction part 13fd and the shape in which the area on the second main surface 11b side is larger than that on the first main surface 11a side ensure high heat dissipation to the heat dissipation member 31 side, as in the other examples.

Figure 23 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a fifth example of the eighth embodiment. With reference to Figure 23, in the heat dissipation device 505 of the fifth example of this embodiment, the first thermal conductive portion 13e of the heat dissipation device 401 is replaced with a core material of the first thermal conductive portion 13ed containing or made of copper molybdenum. Figure 24 is a schematic cross-sectional view showing the configuration of a heat dissipation device according to a sixth example of the eighth embodiment. With reference to Figure 24, in the heat dissipation device 506 of the sixth example of this embodiment, the first thermal conductive portion 13f of the heat dissipation device 402 is replaced with a core material of the first thermal conductive portion 13fd containing or made of copper molybdenum. Even if the thermal conductive portions 13ed and 13fd containing copper molybdenum are used as in Figures 23 and 24, high heat dissipation can be ensured as in the other examples of this embodiment.

In this embodiment, as in the sixth embodiment, a core material of the heat conductive portion 13 containing or made of copper molybdenum may be inserted into the non-through hole portion 15 (second hole portion).

The features described in each of the above-mentioned embodiments (or each of the examples included therein) may be applied in any suitable combination within the scope of technical compatibility.

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than the above description, and it is intended to include all modifications within the meaning and scope of the claims.

11 substrate, 11a first main surface, 11b second main surface, 12 substrate body, 13 heat conductive portion, 13a, 13ad, 13e, 13ed, 13fd, 13gd, 13h, 13i first heat conductive portion, 13b second heat conductive portion, 13c third heat conductive portion, 14 inner layer wiring, 15 hole portion, 16 inner wall conductive film, 17 surface wiring, 17a plating film, 21 mounting component, 22 heat generating component, 23 package, 24, 35 bonding layer, 31 heat dissipation member, 32 solder ball, 33 non-conductive heat dissipation sheet, 34 reflow layer, 34a reflow solder, 36 low temperature solder layer, 36a Low temperature solder, 100a, 100b, 100c, 101, 102, 103, 201, 301, 302, 303, 401, 402, 501, 502, 503, 504, 505, 506 Heat dissipation device.

Claims (11)

a mounting component including a heat generating component and a package for accommodating the heat generating component;
a substrate including: a first main surface on which a first hole is formed, and on which a surface wiring is formed that is joined by a conductive bonding member to a pattern of a conductive film formed on a bottom surface of the package and electrically connected to the heat generating component; a second main surface opposite to the first main surface; a heat conducting portion that transmits heat generated by the heat generating component and that includes an area overlapping with the heat generating component in a plan view, the heat conducting portion penetrating from the first main surface to the second main surface, the first heat conducting portion being formed by a first conductive member filled in the first hole and connected to the surface wiring; and an inner layer wiring formed inside the heat conducting portion;
a heat dissipation device, wherein the first conductive member has a first thread groove formed on its outer peripheral surface, the first hole portion has a second thread groove formed on its inner peripheral surface and the inner peripheral surface is covered with an inner wall conductive film, and the first thread groove and the second thread groove are engaged with each other. The heat dissipation device according to claim 1, wherein the first heat conduction section has a heat dissipation fin formed on a surface opposite to the surface facing the heat generating component. a heat dissipation member provided on a surface of the first thermal conductive portion opposite to a surface facing the heat generating component;
The heat dissipation device according to claim 1 , wherein the heat dissipation member is fixed to the first heat conductive portion by a fastening member inserted into a hole formed in the heat dissipation member and a hole formed in the first heat conductive portion. 4. The heat dissipation device according to claim 1, further comprising a second heat conductive portion arranged around the first heat conductive portion and spaced apart from the first main surface and/or the second main surface. The heat dissipation device according to claim 4 , wherein the second thermally conductive portion is disposed in communication with the second main surface. 6. The heat dissipation device according to claim 4, wherein a sum of an area of a portion of the first heat conductive portion and the second heat conductive portion as the heat conductive portion that connect to the second main surface is greater than a sum of an area of a portion of the first heat conductive portion and the second heat conductive portion as the heat conductive portion that connect to the first main surface. 7. The heat dissipation device according to claim 4 , wherein the second thermal conductive portion is formed by a second conductive member filled in a second hole formed in the substrate. 7. The heat dissipation device according to claim 4 , wherein the second thermal conductive portion is formed of a second conductive member covering an inner wall of a second hole formed in the substrate. The heat dissipation device according to claim 4 , wherein the inner layer wiring is disposed so as to connect the first heat conductive portion and the second heat conductive portion. The heat dissipation device according to claim 1 , further comprising a third heat conductive portion sandwiched between the heat generating component and the first heat conductive portion. The heat dissipation device according to claim 1 , wherein the first thermally conductive portion comprises copper molybdenum.

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