JP2021132155A - Heat transport device and electronic apparatus - Google Patents

Abstract

To provide a heat transport device having an excellent heat dissipation, capable of reducing a thickness, and applying no stress to a substrate.SOLUTION: A heat transport device 11 comprises: a first radiator plate 38 expanded along a back face 20b in a main substrate 20, and contacted to a position corresponding to a chip 34 in the back face 20b; a second radiator plate 40 expanded along a mounting face 20a and contacted to a front face of the chip 34; and a connection tool 42 passing through a through hole 41 of the main substrate 20, and fixing the first radiator plate 38 and the second radiator plate 40 so that a gap between the first radiator plate 38 and the second radiator plate 40 has a predetermined width W. The connection tool 42 comprises: a bolt 44 in which a male screw hole 58 formed in the second radiator plate 40 passes through a male screw part 44b; and a stud 46 built so as to be fixed to the first radiator plate 38 to pass the through hole 41, and to which the male screw part 44b is screwed. The second radiator plate 40 is fixed by an end face 46b of the stud 46 and a head part 44a of the bolt 44.SELECTED DRAWING: Figure 8

Description

The present invention relates to a heat transport device for transporting heat of a heating element and an electronic device including the heat transport device.

Electronic devices are equipped with a heating element such as a CPU, and it is necessary to dissipate heat depending on the power consumption thereof. Patent Document 1 discloses an invention in which heat generated by a CPU is dissipated by a heat sink. The heat sink of Patent Document 1 is a single plate including a heat pipe and a heat spreader, and is in contact with the upper surface of the CPU.

On the other hand, portable electronic devices such as notebook PCs and tablet terminals are required to be further miniaturized and thinned. In portable electronic devices, it is conceivable that a PoP (Package on Package) structure is used in order to reduce the size of the substrate. In the PoP structure, for example, the mounting area can be reduced and the wiring length can be shortened by stacking the logic-based subpackage and the memory-based subpackage and mounting them on the substrate.

The lower layer subpackage in the PoP structure package is covered with the upper layer subpackage, so that the heat dissipation is inferior. In particular, it is desirable to provide some kind of heat transport means in order to make the lower layer subpackage a CPU having a large amount of heat generation. Therefore, Patent Document 2 proposes that a heat radiating member is brought into contact with an upper exposed surface of an electronic component in a lower layer subpackage of PoP to dissipate heat.

Japanese Unexamined Patent Publication No. 2000-349479 Japanese Unexamined Patent Publication No. 2014-116602

In the invention described in Patent Document 2, the heat radiating member is brought into contact with the electronic component of the lower layer subpackage, but the heat radiating member must be interposed in a narrow gap between the lower layer subpackage and the upper layer subpackage, which makes manufacturing difficult. Is. Further, such a heat radiating member cannot be retrofitted to the existing PoP structure.

In order to sufficiently dissipate heat from a heating element having a large amount of heat generation, it is conceivable to provide two heat radiating plates. For example, when the heating element chip 502 is mounted on the upper surface of the substrate 500 as shown in the comparative example of FIG. 11, the first heat radiating plate 504 and the second heat radiating plate 506 are provided. The first heat radiating plate 504 extends along the back surface 500a of the chip 502 on the substrate 500 and comes into contact with the position corresponding to the chip 502 on the back surface 500a. The second heat radiating plate 506 spreads along the mounting surface 500b and comes into contact with the surface of the chip 502. The first heat radiating plate 504 and the second heat radiating plate 506 are fixed to the substrate 500 by studs 508a and 508b, respectively. By using the first heat radiating plate 504 and the second heat radiating plate 506 in this way, heat can be appropriately dissipated even if the chip 502 has a PoP structure.

However, in the example shown in FIG. 11, the first heat radiating plate 504 is fixed to the back surface 500a by the stud 508a, and the second heat radiating plate 506 is fixed to the mounting surface 500b by the stud 508b. Two studs 508a and 508b are interposed in the longitudinal direction to increase the dimension in the height direction, which is contrary to the demand for thinning.

Further, in order to appropriately contact the first heat radiating plate 504 and the second heat radiating plate 506 with the upper surface of the chip 502 and the corresponding portion corresponding to the back surface thereof, it is desirable to arrange the studs 508a and 508b in the vicinity of the chip 502. However, since these studs 508a and 508b are fixed to the substrate 500, bending stress is applied to the substrate 500, and there is a concern that poor contact such as peeling may occur at the soldered portion of the chip 502.

The present invention has been made in view of the above problems, and provides a heat transport device and an electronic device which have good heat dissipation, can be made thinner, and do not give stress to a substrate. The purpose is to do.

In order to solve the above-mentioned problems and achieve the object, the heat transport device according to the first aspect of the present invention is a heat transport device that transports heat of a heating element mounted on a substrate, and the heat transport device in the substrate. A first heat sink that spreads along the back surface opposite to the mounting surface of the heating element and makes thermal contact with the position corresponding to the heating element on the back surface, and spreads along the mounting surface to heat the surface of the heating element. The first heat radiating plate and the second heat radiating plate pass through a through hole formed in the substrate and the second heat radiating plate in contact with each other so that the gap between the first heat radiating plate and the second heat radiating plate has a predetermined width. It is provided with a connector for fixing the plate.

In such a heat transport device, the first heat radiating plate and the second heat radiating plate have better heat radiating properties. Further, since the connector for fixing the first heat radiating plate and the second heat radiating plate passes through the through hole formed in the substrate, it is common to the mounting surface side and the back surface side, so that the thickness can be reduced. Moreover, it does not give stress to the substrate.

The connector is erected through a bolt through which a male screw portion passes through a male screw hole formed in either one of the first heat radiation plate and the second heat radiation plate, and a bolt fixed to the other through the through hole. A stud to which the male screw portion is screwed is provided, and one of the first heat radiating plate and the second heat radiating plate in which the male screw hole is formed has an end face of the stud and a head portion of the bolt. It may be sandwiched and fixed by and.

The connector is erected by passing a male screw hole formed in either one of the first heat radiating plate and the second heat radiating plate through a bolt through which the male screw portion passes and a support hole formed in the other. A stud that is prevented from coming off from the support column hole and into which the male screw portion is screwed is provided, and one of the first heat radiating plate and the second heat radiating plate on which the male screw hole is formed is said to be It may be sandwiched and fixed by the end face of the stud and the head portion of the bolt.

One end of the first heat radiating plate and the second heat radiating plate on which the male screw hole is formed is fixed to a portion that is in thermal contact with the heating element, and the bolt is screwed into the stud. If the other end is provided with a leaf spring that is elastically displaced by being pressed by the head portion, a good thermal connection state is obtained.

The first heat radiating plate is thermally contacted at a position corresponding to the heating element on the back surface, and is fixed to a first thickness portion on which the stud is provided and a side surface of the first thickness portion, and from the first thickness portion. It may also include a thin second thickness portion. The second thickness portion is thicker than the first thickness portion and is suitable for supporting the stud.

The second heat radiating plate is in a good thermal connection state when the contact portion that makes thermal contact with the heating element has a convex shape.

Even if the heating element has a PoP structure, suitable heat dissipation can be obtained.

Further, the electronic device according to the second aspect of the present invention is an electronic device including a heating element, along a substrate on which the heating element is mounted and a back surface opposite to the mounting surface of the heating element on the substrate. A first heat radiating plate that spreads and makes thermal contact with a position corresponding to the heating element on the back surface, and a second heat radiating plate that spreads along the mounting surface and makes thermal contact with the surface of the heating element are formed on the substrate. It is provided with a connector for fixing the first heat radiating plate and the second heat radiating plate so that the gap between the first heat radiating plate and the second heat radiating plate becomes a predetermined width through the through hole.

According to the above aspect of the present invention, it is an object of the present invention to provide a heat transport device and an electronic device which have good heat dissipation, can be made thin, and do not give stress to a substrate.

FIG. 1 is a perspective view showing a state in which the electronic device according to the embodiment is closed and stored. FIG. 2 is a perspective view schematically showing a state in which the electronic device shown in FIG. 1 is opened and used. FIG. 3 is a plan view schematically showing the internal structure of the electronic device shown in FIG. FIG. 4 is an exploded perspective view of the housing member and the components provided inside the housing member. FIG. 5 is a perspective view of the housing member and the components provided inside the housing member. FIG. 6 is a cross-sectional side view of a chip having a PoP structure. FIG. 7 is a perspective view of the auxiliary tool. FIG. 8 is a cross-sectional side view of the heat transport device. FIG. 9 is a cross-sectional side view of the heat transport device according to the first modification. FIG. 10 is a cross-sectional side view of the heat transport device according to the second modification. FIG. 11 is a cross-sectional side view of the heat transport device according to the comparative example.

Hereinafter, embodiments of the heat transport device according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to this embodiment.

FIG. 1 is a perspective view showing a state in which the electronic device 10 according to the embodiment of the present invention is closed and stored. FIG. 2 is a perspective view schematically showing a state in which the electronic device 10 shown in FIG. 1 is opened and used. FIG. 3 is a plan view schematically showing the internal structure of the electronic device 10 shown in FIG. The electronic device 10 includes a heat transport device 11 according to an embodiment of the present invention.

As shown in FIGS. 1 and 2, the electronic device 10 includes two housing members 12A and 12B, a spine member 14, and a display 16. The housing members 12A and 12B are covered with a cover 18. The cover 18 is, for example, polyurethane. In this embodiment, a tablet PC that can be folded in half like a book is illustrated as an electronic device 10. The electronic device 10 may be a mobile phone, a smartphone, an electronic personal organizer, or the like.

The display 16 is, for example, a touch panel type. The display 16 has a structure that can be folded together when the housing members 12A and 12B are folded. The display 16 is, for example, a flexible display such as an organic EL (Electroluminescence) having a highly flexible paper structure, and opens and closes as the housing members 12A and 12B are opened and closed. The display 16 is a liquid crystal type that does not have a foldable structure, and may be provided on either one of the housing members 12A and 12B.

Each of the housing members 12A and 12B is a rectangular plate-shaped member in which side walls are formed upright on three sides other than the side corresponding to the spine cover member 14, respectively. Each housing member 12A and 12B is composed of, for example, a metal plate such as stainless steel, magnesium or aluminum, or a fiber reinforced resin plate containing reinforcing fibers such as carbon fiber. The display 16 is fixed to the inner surface side of the housing members 12A and 12B via a support plate. The housing members 12A and 12B are connected via a pair of hinge mechanisms 19 and 19. The hinge mechanism 19 foldably connects the housing members 12A and 12B to the storage form shown in FIG. 1 and the usage form shown in FIG. The line O indicated by the alternate long and short dash line in FIG. 3 indicates the bending center O which is the center of the folding operation of the housing members 12A and 12B.

As shown in FIG. 3, a heat transport device 11, a main board 20, a communication module 22, an SSD (Solid State Drive) 24, and the like are attached and fixed to the inner surface 12Aa of the housing member 12A. The main substrate 20 and the heat transport device 11 occupy a large area on the inner surface 12Aa of the housing member 12A. A cooling fan 26 is provided at a corner of the housing member 12A. A sub-board 28, an antenna 30, a battery device 32, and the like are attached and fixed to the inner surface 12Ba of the housing member 12B.

FIG. 4 is an exploded perspective view of the housing member 12A and the components provided inside the housing member 12A. FIG. 5 is a perspective view of the housing member 12A and the components provided inside the housing member 12A. In the following description, the direction in which the main substrate 20 is arranged in FIGS. 4 and 5 is upward, and the direction in which the housing member 12A is arranged is downward.

As shown in FIGS. 4 and 5, a PoP-structured chip 34, a chipset 36, and the like are mounted on the mounting surface 20a, which is the upper surface of the main board 20. The chip 34 is a heating element having the largest amount of heat among the electronic components mounted on the electronic device 10. The heat transport device 11 transports the heat of the chip 34 mounted on the main board 20, but it can also be applied to other heating elements (not limited to the PoP structure) mounted on the main board 20. be.

FIG. 6 is a cross-sectional side view of the chip 34 having a PoP structure. The chip 34 is composed of a lower layer subpackage 34a and an upper layer subpackage 34b. The gap between the lower subpackage 34a and the upper subpackage 34b is narrow, and the height dimension of the chip 34 is sufficiently small.

The lower layer subpackage 34a includes a lower layer substrate 34aa and a semiconductor component 34ab. A plurality of solder balls 34ac are provided on the lower surface of the lower layer substrate 34aa, and the solder balls 34ac are electrically connected to the pattern of the main substrate 20. The semiconductor component 34ab is, for example, a CPU (Central Processing Unit). The lower layer substrate 34aa and the semiconductor component 34ab are connected by a plurality of wires 34ad, and signal transmission is performed. The semiconductor component 34ab and the wire 34ad are sealed with the resin 34ae.

The upper layer subpackage 34b includes an upper layer substrate 34ba and a semiconductor component 34bb. A solder ball 34 bc is provided on the lower surface of the upper layer prayer 34 ba, and the solder ball 34 bc is electrically connected to the pattern of the lower layer substrate 34 aa. The semiconductor component 34bb is, for example, a memory. The upper layer substrate 34ba and the semiconductor component 34bb are connected by a plurality of wires 34bb, and signal transmission is performed. The semiconductor component 34bb and the wire 34bd are sealed with the resin 34bed. In such a chip 34, the main substrate 20 can be miniaturized because the lower layer subpackage 34a and the upper layer subpackage 34b have a laminated structure.

Returning to FIGS. 4 and 5, the heat transport device 11 is mounted with a first heat sink 38 that extends along the back surface 20b opposite to the mounting surface 20a and is in thermal contact with a position corresponding to the back side of the chip 34 on the back surface 20b. A gap between the first heat radiating plate 38 and the second heat radiating plate 40 passes through the second heat radiating plate 40 that spreads along the surface 20a and makes thermal contact with the surface of the chip 34 and the through hole 41 formed in the main substrate 20. A connector 42 for fixing the first heat radiating plate 38 and the second heat radiating plate 40 so as to have a predetermined width W (see FIG. 8) is provided. The thermal contact is a contact so as to be able to transfer heat, and includes not only direct contact but also contact via a heat transfer body, heat transfer grease, or the like.

Three through holes 41 and three connecting tools 42 are provided near the chip 34 at substantially equal intervals. The first heat radiating plate 38 and the second heat radiating plate 40 of the heat transport device 11 are set to be larger than the main substrate 20 in a plan view. In the main board 20, many electronic components including the chip 34 are mounted on the mounting surface 20a, but some components may be mounted on the back surface 20b depending on the design conditions.

The connector 42 includes a bolt 44 and a stud 46. An auxiliary tool 48 is caulked and fixed to the second heat radiating plate 40. The auxiliary tool 48 is a member fixed to the second heat radiating plate 40, but in FIG. 4, the auxiliary tool 48 and the second heat radiating plate 40 are shown separately for easy understanding. The bolt 44, the stud 46 and the auxiliary tool 48 will be described later.

The first heat radiating plate 38 includes a heat pipe 50 that is thermally connected to the chip 34 via the main substrate 20 and a heat spreader 54 that is thermally connected to the heat pipe 50 to dissipate heat.

The heat pipe 50 has, for example, a structure in which a metal pipe having both ends joined to form a closed space inside is crushed, and heat is efficiently transported by utilizing the phase change of the working fluid sealed in the closed space. It is a possible heat transport device. A part of the heat pipe 50 is arranged so as to be thermally connected to the back side of the chip 34 on the back surface 20b of the main substrate 20, and the end portion 50a can transfer heat to the cooling fan 26 connected to the air outlet of the cooling fan 26. It is connected. The heat pipe 50 is thermally connected to the main substrate 20 via the heat transfer plate 52, but may be in direct contact with the main substrate 20.

The cooling fan 26 is arranged in the vicinity of the end portion 50a, and takes in air from one of the ventilation holes 12Aa on one side surface of the housing member 12A and the ventilation holes 12Ab on the other side surface and exhausts the air to the other side of the heat pipe 50. Dissipate heat.

The heat spreader 54 has a first thickness portion 54a fixed so as to surround a portion of the heat pipe 50 other than the end portion 50a, and a first thickness portion 54a fixed to the side surface thereof so as to surround substantially the entire circumference of the first thickness portion 54a. It has two thickness portions 54b. The heat pipe 50 and the first thickness portion 54a have the same thickness (see FIG. 8). The second thickness portion 54b is thinner than the first thickness portion 54a (see FIG. 8). The side of the heat spreader 54 on the side where the end portion 50a is arranged is formed of substantially only the first thickness portion 54a.

Since the first thickness portion 54a is thicker than the second thickness portion 54b, the protruding end portion 50a can be stably supported. The heat pipe 50, the first thickness portion 54a and the second thickness portion 54b extend along the inner surface 12Aa and do not overlap in the vertical direction. The first thickness portion 54a has an area equal to or larger than that of the heat pipe 50. The second thickness portion 54b has a larger area than the first thickness portion 54a.

The heat pipe 50 and the first thickness portion 54a are fixed and in contact with each other by, for example, pressing or press fitting. In the press fitting of the heat pipe 50 and the first thickness portion 54a, for example, the metal pipe and the base material of the first thickness portion 54a are simultaneously pressurized by the rolling of a roller, and the metal pipe is crushed to form the heat pipe 50. At the same time, the first thickness portion 54a can be press-fitted into the side surface thereof.

The first thickness portion 54a and the second thickness portion 54b are fixed and in contact with each other by, for example, pressing or press fitting. The boundary between the first thickness portion 54a and the second thickness portion 54b may be connected by a comb-teeth-shaped meshing portion continuously provided over substantially the entire circumference. A notch 50 that avoids the cooling fan 26 is formed in the corner of the second thick portion 54b.

The heat transfer plate 52 and the heat spreader 54 are metal plates having high heat transfer properties, such as aluminum, copper, stainless steel, or alloys thereof. The first thickness portion 54a and the second thickness portion 54b of the heat spreader 54 may be made of the same material or different materials. If the first thickness portion 54a, which is thicker than the second thickness portion 54b, is made of aluminum, weight reduction can be achieved. When the second thickness portion 54b, which is thinner than the first thickness portion 54a, is made of copper, heat can be widely diffused due to its high heat conductivity.

A part of the heat pipe 50 is in thermal contact with the back surface 20b of the main substrate 20 via the heat transfer plate 52, and heat is transferred to the heat spreader 54 and the cooling fan 26. The heat spreader 54 has a sufficiently large area, and receives heat from the heat pipe 50 to dissipate heat. Further, the cooling effect is further enhanced by receiving the wind from the cooling fan 26 at the end portion 50a of the heat pipe 50. However, the cooling fan 26 may be omitted depending on the thermal conditions.

The second heat sink 40 is a heat spreader, and for example, the same material can be applied with the same thickness as the second thickness portion 54b. The second heat radiating plate 40 has substantially the same shape as the first heat radiating plate 38 in a plan view, and has an appropriately large area. The second heat radiating plate 40 includes a convex portion 56 having a convex shape downward. The convex portion 56 is formed by, for example, press molding, and has a gently substantially truncated cone shape that opens upward, and includes a bottom portion 56a and a tapered portion 56b. The bottom portion 56a, which is the lower surface of the convex portion 56, makes thermal contact with the upper surface of the chip 34. Auxiliary tool 48 is caulked and fixed to the bottom portion 56a. The second heat radiating plate 40 is formed with three male screw holes 58 around the convex portion 56. The male screw hole 58 is coaxial with the through hole 41 and the stud 46.

The second heat radiating plate 40 is fixed to a plurality of bosses 47b provided on the inner surface 12Aa by screws 49. The first heat radiating plate 38 is fixed to the second heat radiating plate 40 by the connector 42 as described above. The main substrate 20 is fixed to a plurality of bosses 47Aa provided on the inner surface 12Aa by screws (not shown), but is not directly fixed to the first heat radiating plate 38 and the second heat radiating plate 40.

The second heat radiating plate 40 is fixed to a plurality of bosses 47b provided on the inner surface 12Aa by screws 49. The first heat radiating plate 38 is fixed to the second heat radiating plate 40 by the auxiliary tool 48 as described above. The main substrate 20 is fixed to a plurality of bosses 47a provided on the inner surface 12Aa by screws (not shown), but is basically not directly fixed to the first heat radiating plate 38 and the second heat radiating plate 40.

FIG. 7 is a perspective view of the auxiliary tool 48. The auxiliary tool 48 includes a disk 60 and three arms 62. The auxiliary tool 48 is configured by, for example, cutting a stainless steel plate and press-molding it. The disk 60 has a circular shape slightly smaller than the bottom portion 56a of the convex portion 56 (see FIG. 8), and is a portion fixed by thermal contact with the bottom portion 56a. The disk 60 is caulked and fixed to the bottom portion 56a at three points in the middle portion of each arm 62 in the circumferential direction, for example.

The arm 62 has an inclined portion 62a projecting diagonally upward from a substantially intermediate portion in the radial direction of the disk 60, a horizontal portion 62b projecting horizontally from the inclined portion 62a, and a small downward step from the horizontal portion 62b. It is provided with a bolt seat 62c that further protrudes through. The three arms 62 are formed radially at equal intervals.

A bolt 44 is rotatably provided on the bolt seat 62c. A head portion 44a is provided on the upper surface of the bolt seat 62c, and the male screw portion 44b projects downward from the bolt seat 62c through the hole 62d (see FIG. 8). The washer 64 is fitted into the male screw portion 44b so as not to fall off.

FIG. 8 is a cross-sectional side view of the heat transport device 11. 8 to 10 show a cross section along the center of two of the three arms 62.

As shown in FIG. 8, the stud 46 is press-fitted and fixed to the press-fitting hole 38a provided in the first thickness portion 54a and stands upward. The amount of protrusion of the stud 46 from the upper surface of the first heat radiating plate 38 is a specified predetermined width W. The stud 46 penetrates the through hole 41 of the main board 20. The through hole 41 through which the stud 46 penetrates may be copper-plated as a part of the circuit pattern on the main substrate 20, or may be a hole through which the stud 46 without the copper plating is simply passed. When the through hole 41 is copper-plated, an insulating coating may be provided on at least one of the through hole 41 and the stud 46.

The stud 46 is connected to the press-fitting hole 38a by, for example, a serration structure, and is fixed so as not to move up and down and to be non-rotatable. Since the stud 46 is fixed to the first thickness portion 54a, which is thicker than the second thickness portion 54b, it is easy to fix and stable. The through hole 41 has a larger diameter than the stud 46, and a slight gap is formed between the two. A female screw portion 46a is formed on the stud 46.

The male screw portion 44b of the bolt 44 is screwed into the female screw portion 46a of the stud 46 through the male screw hole 58 formed in the second heat radiating plate 40. The second heat radiating plate 40 on which the male screw hole 58 is formed is sandwiched and fixed by the end face 46b of the stud 46 and the head portion 44a of the bolt 44 via the bolt seat 62c and the washer 64, and is fixed to the first heat radiating plate 38. The distance from the second heat radiating plate 40 is a predetermined width W. As a result, in the downward convex portion 56 of the second heat radiating plate 40, the tapered portion 56b is slightly elastically deformed, and the bottom portion 56a elastically contacts the upper surface of the chip 34.

Further, as shown by the virtual line, the arm 62 is located slightly upward in the natural state where the bolt 44 is not screwed to the stud 46, but is elastically deformed when the bolt 44 is screwed to the stud 46. Pushed down, the bolt seat 62c comes into contact with the upper surface of the second heat radiating plate 40 via the washer 64. That is, one end of the arm 62 is fixed to the bottom portion 56a that is in thermal contact with the tip 34 of the second heat sink 40, and the other end is elastically displaced by being pressed by the head portion 44a by screwing the bolt 44 into the stud 46. do. In this way, the arm 62 acts as a leaf spring. Since the arm 62 acts like a spring washer, the bolt 44 is difficult to come off from the stud 46. Further, due to the action of the arm 62 as a leaf spring, the disk 60 is further pressed against the tip 34 to make it difficult for a gap to be generated, and the heat transfer property is improved. Since three arms 62 are provided at equal intervals, the bottom portion 56a can be pressed in a well-balanced manner.

By the way, the lower layer subpackage 34a (see FIG. 6) of the chip 34 having a PoP structure is a CPU having a large amount of heat generation, but since it is covered with the upper layer subpackage 34b, it is inferior in heat dissipation by itself. On the other hand, in the heat transport device 11 and the electronic device 10 according to the present embodiment, good heat dissipation is realized by the first heat radiating plate 38 and the second heat radiating plate 40, and the temperature of the chip 34 rises excessively. Is being prevented. That is, the first heat radiating plate 38 makes thermal contact with the position corresponding to the back side of the chip 34 on the back surface 20b of the main substrate 20, and receives the heat of the chip 34 via the solder ball 34ac, the main substrate 20, and the heat transfer plate 52. To dissipate heat. The first heat radiating plate 38 has a heat transfer property because a heat pipe 50 is provided on the back surface portion of the chip 34 and a relatively thick first thickness portion 54a is connected around the heat pipe 50. Further, since a wide second thickness portion 54b is connected to the side surface of the first thickness portion 54a, heat dissipation is high.

On the other hand, the convex portion 56 of the second heat radiating plate 40 is in contact with the upper surface of the chip 34, and is pressed appropriately strongly by the elasticity of the tapered portion 56b and the arm 62, so that there is no gap and the heat transfer property is high. .. In this way, in the heat transport device 11 and the electronic device 10, heat can be received and dissipated from the upper surface side and the lower surface side with respect to the chip 34 which is a heating element mounted on the main substrate 20, and the chip 34 can receive heat. It is possible to prevent the temperature from rising excessively. Therefore, a component having a large power consumption can be applied as the chip 34.

Further, the first heat radiating plate 38 and the second heat radiating plate 40 are maintained at an appropriate predetermined width W by the studs 46, but the studs 46 are loosely fitted to the through holes 41 of the main board 20 with a gap. Therefore, no stress is applied to the main board 20, and poor contact between the solder balls 34ac and the main board 20 is unlikely to occur. The gap between the stud 46 and the through hole 41 may be set to a tolerance such that no force acts between the stud 46 and the through hole 41, or may be substantially zero. Further, since the stud 46 does not apply stress to the main substrate 20, it can be arranged in the vicinity of the chip 34, whereby the first heat radiating plate 38 and the second heat radiating plate 40 are appropriately thermally contacted with the chip 34. Can be made to.

Further, as described with reference to FIG. 11, assuming that the first heat radiating plate 504 and the second heat radiating plate 506 are fixed by the studs 508a and 508b protruding from both sides of the main substrate 500, the height of the heat transport device is high. The vertical dimension becomes large, which violates the demand for thinner electronic devices. On the other hand, in the heat transport device 11 according to the present embodiment, since the first heat radiating plate 38 and the second heat radiating plate 40 are supported by the studs 46 penetrating the through hole 41, the dimensions in the height direction are large. It is small and the electronic device 10 can be made thin.

FIG. 9 is a cross-sectional side view of the heat transport device 11A according to the first modification. FIG. 10 is a cross-sectional side view of the heat transport device 11B according to the second modification. In the heat transport devices 11A and 11B, the same components as those of the heat transport device 11 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 9, in the heat transport device 11A according to the first modification, the stud 46A is provided in place of the stud 46 described above. A retaining flange 46c is provided at the lower end of the stud 46A. The stud 46A is erected through the support column hole 38aa formed in the first heat radiating plate 38, and the male screw portion 44b is screwed into the female screw portion 46a. The stud 46A is prevented from coming off by the flange 46c with respect to the support hole 38aa.

The strut hole 38aa is formed at the same position as the press-fitting hole 38a (see FIG. 8), but the stud 46A has a smaller diameter than the strut hole 38aa and is not press-fitted and fixed. Further, the stud 46 and the support hole 38aa have a non-circular cross section (for example, a hexagon), and the stud 46A is prevented from rotating with respect to the first heat radiating plate 38. That is, the stud 46A can move up and down within the range of the retaining regulation by the flange 46c, and is provided so as not to rotate with respect to the first heat radiating plate 38. In such a heat transport device 11A, the distance between the first heat radiating plate 38 and the second heat radiating plate 40 is maintained at a predetermined width W, similarly to the heat transport device 11 described above. Therefore, the first heat radiating plate 38 abuts on the back surface 20b of the main substrate 20 via the heat transfer plate 52, and the second heat radiating plate 40 abuts on the upper surface of the chip 34, so that the heat receiving and heat radiating properties are excellent. Further, since the stud 46A penetrates the through hole 41, no stress is applied to the main substrate 20.

As shown in FIG. 10, the components of the heat transport device 11B according to the second modification are basically the same as those of the above heat transport device 11, but the first heat sink 38 and the second heat sink 40 The position is reversed. That is, the first heat radiating plate 38 is in contact with the upper surface of the chip 34, and the convex portion 56 of the second heat radiating plate 40 is in contact with the back side corresponding portion of the chip 34 on the back surface 20b of the main substrate 20. The stud 46 fixed to the first heat radiating plate 38 projects downward, and the bolt 44 is screwed into the female screw portion 46a of the stud 46 with the male screw portion 44b facing upward. In such a heat transport device 11B, the same operation as that of the heat transport device 11 can be obtained.

In other words, the male screw portion 44b of the bolt 44 passes through the male screw hole 58 formed in either the first heat radiation plate 38 or the second heat radiation plate 40, and the stud 46 is fixed to the other and is fixed to the main substrate. It suffices that the male screw portion 44b is screwed into the erection through the through hole 41 of 20.

The present invention is not limited to the above-described embodiment, and it goes without saying that the present invention can be freely modified without departing from the gist of the present invention.

10 Electronic equipment 11, 11A, 11B Heat transport device 20 Main board 20a Mounting surface 20b Back surface 34 Chip (heating element)
34a Lower layer subpackage 34b Upper layer subpackage 38a Press-fit hole 38aa Strut hole 38 First heat dissipation plate 40 Second heat dissipation plate 41 Through hole 42 Connector 44 Bolt 44a Head part 44b Male thread part 46, 46A Stud 46a Female thread part 46b End face 46c Flange 48 Auxiliary tool 50 Heat pipe 52 Heat transfer plate 54 Heat spreader 54a First thickness part 54b Second thickness part 56 Convex part 56a Bottom 56b Tapered part 58 Male screw hole 60 Disc 62 Arm (leaf spring)
62a Inclined part 62b Horizontal part 62c Bolt seat W Predetermined width

Claims (8)

A heat transport device that transports the heat of a heating element mounted on a substrate.
A first heat sink that spreads along the back surface of the substrate opposite to the mounting surface of the heating element and is in thermal contact with a position corresponding to the heating element on the back surface.
A second heat sink that spreads along the mounting surface and makes thermal contact with the surface of the heating element.
A connector for fixing the first heat sink and the second heat sink so that the gap between the first heat sink and the second heat sink becomes a predetermined width through a through hole formed in the substrate. ,
A heat transport device comprising. In the heat transport device according to claim 1,
The connector is
A bolt through which the male screw portion passes through a male screw hole formed in either the first heat radiating plate or the second heat radiating plate.
A stud that is fixed to the other side and stands up through the through hole, and the male screw portion is screwed into the stud.
With
One of the first heat radiating plate and the second heat radiating plate in which the male screw hole is formed is sandwiched and fixed by the end face of the stud and the head portion of the bolt. .. In the heat transport device according to claim 1,
The connector is
A bolt through which the male screw portion passes through a male screw hole formed in either the first heat radiating plate or the second heat radiating plate.
A stud that is erected through a support hole formed on the other side, is prevented from coming off from the support hole, and the male screw portion is screwed into the stud.
With
One of the first heat radiating plate and the second heat radiating plate in which the male screw hole is formed is sandwiched and fixed by the end face of the stud and the head portion of the bolt. .. In the heat transport device according to claim 2 or 3.
One end of the first heat radiating plate and the second heat radiating plate on which the male screw hole is formed is fixed to a portion that is in thermal contact with the heating element, and the bolt is screwed into the stud. A heat transport device comprising a leaf spring whose other end is elastically displaced by being pressed by the head portion. In the heat transport device according to any one of claims 2 to 4.
The first heat radiating plate is
A first-thickness portion on the back surface that is in thermal contact with a position corresponding to the heating element and is provided with the stud.
A second thickness portion fixed to the side surface of the first thickness portion and thinner than the first thickness portion,
A heat transport device comprising. In the heat transport device according to any one of claims 1 to 5.
The second heat radiating plate is a heat transport device characterized in that a contact portion that makes thermal contact with the heating element has a convex shape. In the heat transport device according to any one of claims 1 to 6.
A heat transport device characterized in that the heating element has a PoP structure. An electronic device equipped with a heating element
The substrate on which the heating element is mounted and
A first heat sink that spreads along the back surface of the substrate opposite to the mounting surface of the heating element and is in thermal contact with a position corresponding to the heating element on the back surface.
A second heat sink that spreads along the mounting surface and makes thermal contact with the surface of the heating element.
A connector for fixing the first heat sink and the second heat sink so that the gap between the first heat sink and the second heat sink becomes a predetermined width through a through hole formed in the substrate. ,
An electronic device characterized by being equipped with.

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