WO2015049807A1

WO2015049807A1 - Server device

Info

Publication number: WO2015049807A1
Application number: PCT/JP2013/077186
Authority: WO
Inventors: 健太郎佐野; 西原　淳夫; 加藤　猛; 智子依田
Original assignee: 株式会社日立製作所
Priority date: 2013-10-04
Filing date: 2013-10-04
Publication date: 2015-04-09

Abstract

[Problem] To provide a server device which is capable of both mounting heating members in high density and achieving high cooling performance. [Solution] The server device comprises a circuit board (21) on which heating members (22b) and a heat-radiating member (23) are mounted on one surface and another surface, respectively, so as to face each other; and a sealed container (11) housing the circuit board in the interior thereof. The circuit board is provided in the interior with a plurality of thermal vias (25) thermally connecting the heating members and the heat-radiating member, and the heat-radiating member is immersed, in the interior of the sealed container, in an insulating inert refrigerant (31) in a liquid phase state.

Description

Server device

The present invention relates to a server device that can achieve both high-density mounting of heat generating members and high cooling performance for cooling the heat generating members.

For example, a rack-mount type server device accommodates a large number of server modules inside a rack cabinet. Each server module has a configuration in which a large number of electronic devices such as a CPU and a memory are mounted on a circuit board. The electronic device serves as a heat generating member that generates heat. Therefore, the server device needs to cool the electronic device. As a technique for cooling an electronic device, for example, there is a technology in which a circuit board on which an electronic device is mounted is configured as described in (1) to (3) below.

(1) For example, the circuit board described in Patent Document 1 is made of glass ceramics, has an insulating substrate having a mounting portion for a heat generating element on its upper surface, a wiring conductor electrically connected to the heat generating element, and mounting And a through conductor for radiating the heat generated by the heat generating element on the lower surface side of the insulating substrate. The through conductor contains copper in a proportion of 85% by volume or more, and is formed by firing simultaneously with the insulating substrate. In such a configuration, the heat-generating element constitutes an electronic device that serves as a heat-generating member.

Since this circuit board can obtain a thermal conductivity of 20 W / m · K or more, which is the same as that of an alumina wiring board, it is possible to efficiently cool the heat-generating element that is a heat-generating member.

(2) For example, the circuit board described in Patent Document 2 is made of an insulating material, has an electronic device mounting portion on the surface side, and has an electrically conductive pattern formed at least on the surface side. And a thermal via provided at the mounting position. The thermal via has a configuration in which a thermally conductive material connected to an electronic device is filled in through holes provided in the front surface side and the back surface side of the insulating substrate. The thermal via is formed so that the opening area on the front surface side of the substrate is smaller than the opening area on the back surface side of the substrate. The electronic device is mounted on the surface side of the substrate through a plurality of bumps made of a conductive material. At least one of the bumps is connected to the thermally conductive material at a position corresponding to the opening on the surface side of the thermal via.

This circuit board is formed such that the opening area on the front surface side of the thermal via is smaller than the opening area on the back surface side, and the bump for mounting the electronic device on the substrate is connected to the thermal via. This circuit board is formed so that the opening area of the thermal via on the surface side of the board is small. Therefore, this circuit board can arrange a conductor pattern etc. on the surface side of a board with high density. Further, this circuit board is formed with a large opening area of the thermal via on the back side of the board. Therefore, this circuit board can efficiently dissipate heat generated in the electronic device from the back side of the board. The circuit board is mounted with bumps in a state where the electronic device is lifted from the board by each bump. Therefore, this circuit board can stabilize the heat radiation path from the electronic device to the thermal via via each bump.

For example, even if this circuit board supplies a large amount of power to an electronic device that is a heat-generating member, the thermal via improves the heat dissipation of the electronic device and increases the opening area on the surface side of the thermal via as necessary. Since it can be formed small, it is possible to achieve both miniaturization of the entire device and securing of heat dissipation.

(3) For example, the circuit board described in Patent Document 3 is composed of a sintered body of a glass ceramic composition containing glass powder and a ceramic filler, and has a substrate having a mounting surface on which a semiconductor element is mounted, and a plurality of substrates The layer is formed by being laminated from the mounting surface to the non-mounting surface opposite to the mounting surface, and includes a thermal via for radiating heat generated in the semiconductor element on the lower surface side of the substrate. The thermal via is formed by laminating layers having different diameters of the opening. The thermal via is formed so that the diameter on the non-mounting surface side is larger than the diameter on the mounting surface side in at least two arbitrary layers in contact with each other among the layers. In such a configuration, the semiconductor element constitutes an electronic device serving as a heat generating member.

This circuit board can prevent an increase in the heat transfer resistance of the thermal via even when the position of the through hole of each layer is shifted when forming each layer of the thermal via.

JP 2004-228410 A JP 2003-338777 A JP 2012-18948 A

However, all of the conventional techniques described in Patent Documents 1 to 3 provide high cooling performance for mounting the heat generating members at a high density and cooling the heat generating members as described below. There was a problem that it was difficult to achieve both.

For example, since the server device needs to accommodate the server module within one unit standard of the rack cabinet, the server module is reduced in size and thickness. In addition, the server device is required to increase the processing speed and communication speed of the server module, and in order to satisfy this demand, high performance and high density mounting of the electronic device which is a heat generating member is achieved. . As a result, the amount of heat generated inside the server device tends to increase.

Such a server device requires a cooling system that saves space and has high cooling performance. Therefore, a liquid cooling system cooling system is used in many server devices. The liquid cooling type cooling system is a system that cools a space around an electronic device using a cooling liquid.

According to the conventional techniques described in Patent Documents 1 to 3, the distance between electronic devices on the circuit board needs to be shortened to be dense when improving the communication speed of the server module. The area of the circuit board is reduced, and as a result, the heat dissipation area of the circuit board is limited.

However, the prior art described in Patent Document 1 and Patent Document 2 uses an air-cooled cooling system via a circuit board. For example, the conventional techniques described in Patent Document 1 and Patent Document 2 are configured to conduct heat from an electronic device, which is a heat generating member, to a refrigerant via a circuit board. Such conventional techniques described in Patent Document 1 and Patent Document 2 have the following problems (1) to (3), for example.

(1) Since the prior art described in Patent Document 1 and Patent Document 2 cannot secure a sufficient heat radiation area, the cooling performance is insufficient.
(2) Since the conventional techniques described in Patent Document 1 and Patent Document 2 require a large heat dissipation surface even if a sufficient cooling area is to be ensured, there is a space for arranging a large number of electronic devices. Run short.
(3) Heat is not diffused sufficiently on the wide heat dissipation surface. For this reason, the conventional techniques described in Patent Document 1 and Patent Document 2 are difficult to bring out all the performance of the heat dissipation surface even if it is intended to secure a sufficient cooling area, and only a low cooling performance with respect to the secured area. Can't get.

Further, in the conventional technique described in Patent Document 3, the thermal via is formed by laminating layers having different diameters of the opening, so that the diameter of the thermal via on the non-mounting surface side is larger than the diameter on the mounting surface side. Is formed. Thereby, the prior art described in Patent Document 3 improves the heat dissipation performance of the circuit board.

However, in the prior art described in Patent Document 3, in order to form openings having different diameters for each layer to be laminated, a manufacturing process using drills having different diameters for each layer is required, which increases the manufacturing cost. There was a problem to do.

The present invention has been made in order to solve the above-described problems, and is a server device capable of achieving both mounting of heat generating members at high density and obtaining high cooling performance for cooling the heat generating members. The main purpose is to provide

In order to achieve the above object, the first invention is a server device, wherein the heat generating member and the heat radiating member are mounted on one surface and the other surface so as to face each other, and the circuit substrate The circuit board includes a plurality of thermal vias that thermally connect the heat generating member and the heat radiating member, and the heat radiating member includes the airtight container. It is set as the structure immersed in the insulating inert refrigerant | coolant of a liquid phase state inside.

In this server device, since the heat generating member and the heat radiating member are separately mounted on one surface and the other surface of the circuit board, the heat generating member can be mounted with high density. Moreover, since this server apparatus mounts a heat radiating member in an empty space on the other surface of the circuit board on which the heat generating member is not mounted, a heat radiating member having a mounting area larger than the mounting area of the heat generating member is mounted on the circuit board. As a result, high cooling performance for cooling the heat generating member can be obtained. In addition, since the heat generating member and the heat radiating member are thermally connected to each other by a thermal via and the heat radiating member is immersed in an insulating inert refrigerant in a liquid phase state, this server device also provides high cooling. Performance can be obtained.

The second invention is a server device, wherein a circuit board in which two or more layers of a resin substrate and an insulating substrate are laminated, a heat generating member mounted on one surface of the circuit board, and the other of the circuit boards A heat dissipating member mounted at a position facing the heat generating member on the surface of the surface, and a plurality of thermal vias formed inside the circuit board and thermally connecting the heat generating member and the heat dissipating member, The thermal via is connected to the heat generating member and the heat dissipating member through a heat transfer member disposed inside the circuit board so that N> M, where N> M (where N and M are both An integer), and between the heat generating member and the thermal via and between the heat radiating member and the thermal via, respectively, are connected by a solder material, and between the heat radiating member and the thermal via, The solder material for connecting the Than solder material for connecting between the heat member and the thermal via a configuration that has a larger diameter.

In this server device, since the heat generating member and the heat radiating member are separately mounted on one surface and the other surface of the circuit board, the heat generating member can be mounted with high density. Moreover, since this server apparatus mounts a heat radiating member in an empty space on the other surface of the circuit board on which the heat generating member is not mounted, a heat radiating member having a mounting area larger than the mounting area of the heat generating member is mounted on the circuit board. As a result, high cooling performance for cooling the heat generating member can be obtained. In this server device, the solder material connecting the heat radiating member and the thermal via is formed to have a larger diameter than the solder material connecting the heat generating member and the thermal via. While efficiently dissipating the heat radiating member having a larger mounting area than the mounting area of the member on the circuit board, the heat transfer efficiency can be increased, and as a result, high cooling performance can be obtained.
Other means will be described later.

According to the present invention, it is possible to provide a server device that can achieve both high-density mounting of heat-generating members and high cooling performance for cooling the heat-generating members.

FIG. 1 is a diagram illustrating a schematic configuration of a server device and a cooling system used for cooling the server device according to the first embodiment. 2A and 2B are diagrams illustrating a schematic configuration of a 1U server that configures the server device according to the first embodiment, and FIG. 2A is a top view of the 1U server. b) is a perspective view of the 1U server with the guide rail removed. FIG. 3 is a perspective view illustrating a schematic configuration of a server module incorporated in the server apparatus according to the first embodiment. FIG. 4 is a perspective cross-sectional view illustrating a schematic configuration of the server module according to the first embodiment. FIG. 5 is a diagram illustrating a state of the server module during operation of the server apparatus according to the first embodiment. FIG. 6 is a diagram (1) illustrating an example of a method of manufacturing a circuit board incorporated in the server module according to the first embodiment. FIG. 7 is a diagram (2) illustrating an example of a method of manufacturing a circuit board incorporated in the server module according to the first embodiment. FIG. 8 is a diagram illustrating a schematic configuration of a server module according to the second embodiment. FIG. 9 is a diagram illustrating an example of a method of manufacturing a circuit board incorporated in the server module according to the second embodiment. FIG. 10 is a diagram illustrating an example of a method for manufacturing a circuit board incorporated in a server module according to a modification of the second embodiment. FIG. 11 is a diagram illustrating a schematic configuration of a server module according to the third embodiment. FIG. 12 is a diagram illustrating a schematic configuration of a server module according to the fourth embodiment. FIG. 13 is a perspective view showing a schematic configuration of the first modification. FIG. 14 is a cross-sectional view showing a schematic configuration of the second modification.

Hereinafter, an embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail with reference to the drawings. Each figure is only schematically shown so that the present invention can be fully understood. Therefore, the present invention is not limited to the illustrated example. Moreover, in each figure, the same code | symbol is attached | subjected about the common component and the same component, and those overlapping description is abbreviate | omitted. Moreover, the figure which shows each manufacturing method has shown the cut surface of the cross section of the principal part of the structure obtained at each process step.

[Embodiment 1]
<Configuration of server device and cooling system>
Hereinafter, the configuration of the server device 1 according to the first embodiment and the cooling system 160 used for cooling the server device 1 will be described with reference to FIG. FIG. 1 is a diagram illustrating a schematic configuration of a server device 1 according to the first embodiment and a cooling system 160 used for cooling the server device 1. Here, a description will be given assuming that the server device 1 according to the first embodiment is configured as a rack mount server.

As illustrated in FIG. 1, the server device 1 according to the first embodiment includes a plurality of 1U servers 3 and is configured to accommodate each 1U server 3 in a rack cabinet 110. The 1U server 3 is a device on which a plurality of server modules 10 having server functions are mounted. The configurations of the 1U server 3 and the server module 10 will be described later.

The rack cabinet 110 includes

columns

111 and 112, guide rails 113, a backplane 121, a coolant circulation path 161, a coolant supply buffer tank 162, and a coolant discharge buffer tank 163. .

The support 111 is a vertical support that constitutes the rack cabinet 110.
The column 112 is a horizontal column that constitutes the rack cabinet 110.
The guide rail 113 is a member that slidably holds the 1U server 3 in the arrow A1 direction or the arrow A2 direction.
The backplane 121 is a part that houses equipment such as a power connector and an optical cable.

The coolant circulation path 161 is a pipe that circulates the coolant 2 between each server module 10 and a chiller 164 described later.
The coolant supply buffer tank 162 is a tank that temporarily stores the coolant 2 supplied to each server module 10.
The coolant discharge buffer tank 163 is a tank that temporarily stores the coolant 2 discharged from each server module 10.

In the example shown in FIG. 1, the rack cabinet 110 is configured such that the backplane 121 is disposed in the center and the 1U server 3 is accommodated on each of the front side and the back side of the page. The server apparatus 1 uses the rack cabinet 110 in which the backplane 121 is arranged in the center, so that the server module 10 on the front side of the page is detached in the direction of arrow A1, and the server module 10 on the back side of the page is detached in the direction of arrow A2. Can be realized simultaneously.

In the example shown in FIG. 1, only one 1U server 3 is shown on the front side and the back side of the paper, but the rack cabinet 110 includes a plurality of 1U servers 3 on the front side and the back side of the paper. It is configured to be accommodated in each. In the example shown in FIG. 1, only one rack cabinet 110 is provided, but a plurality of rack cabinets 110 may be provided.

The rack cabinet 110 constitutes a cooling system 160 that cools electronic devices mounted on each server module 10 by using the coolant 2 together with a chiller 164 installed outside (for example, outside the building).

The chiller 164 is a cooling device that cools the coolant 2. The chiller 164 supplies the coolant 2 to each server module 10 via the coolant circulation path 161, collects the coolant 2 discharged from each server module 10, and cools the coolant 2. Here, the case where the coolant 2 is water will be described. However, the coolant 2 may be a refrigerant other than water.

In the example shown in FIG. 1, the coolant circulation path 161 includes coolant supply pipes 161Aa and 161Ab and coolant discharge pipes 161Ba and 161Bb.

The coolant supply pipes 161 Aa and 161 Ab are pipes for sending the coolant 2 from the coolant supply buffer tank 162 to each server module 10. The coolant supply pipe 161Aa is provided so as to pass through the backplane 121. The coolant supply pipe 161Ab is provided so as to pass through the guide rail 113.

The cooling liquid discharge pipes 161Ba and 161Bb are pipes for sending the cooling liquid 2 from the server modules 10 to the cooling liquid discharge buffer tank 163, respectively. The coolant discharge pipe 161Ba is provided so as to pass through the backplane 121. The coolant discharge pipe 161Bb is provided so as to pass through the guide rail 113.

<Configuration of 1U server>
Hereinafter, the configuration of the 1U server 3 will be described with reference to FIG. FIG. 2 is a diagram illustrating a schematic configuration of the 1U server 3. FIG. 2A shows the configuration of the 1U server 3 in a state cut along the cutting plane CT1 shown in FIG. FIG. 2B shows the configuration of the 1U server 3 with the guide rail 113 removed.

As shown in FIG. 2A, the 1U server 3 includes a wiring unit 5, a server module 10, and a guide rail 113. In the example illustrated in FIG. 2A, the 1U server 3 includes eight server modules 10 and two guide rails 113. Four server modules 10 are arranged on both sides of the wiring section 5. Two guide rails 113 are arranged on the right side and the left side of the 1U server 3 one by one.

The wiring unit 5 is a part that accommodates communication cables and power lines. The communication cable communicatably connects each server module 10 including the server module 10 housed in another rack cabinet 110 (not shown) and an electronic device (not shown). Note that the communication cable may have a function of performing communication using not only an electric signal but also an optical signal.

As shown in FIG. 2B, the two guide rails 113 each include a cooling liquid supply pipe 161Ab and a cooling liquid discharge pipe 161Bb that constitute the cooling liquid circulation path 161 therein.

One end of the coolant supply pipe 161Ab is connected to the coolant supply pipe 161Aa (see FIG. 1), and the other end is provided in each server module 10 by the connection portion 114a. 5)) is connected to the supply hole 4a. The coolant discharge pipe 161Bb has one end connected to the coolant discharge pipe 161Ba (see FIG. 1) and the other end provided to each server module 10 by the connection portion 114b. And the discharge hole 4b of FIG. 5). Therefore, the two guide rails 113 have a function of forming a coolant circulation path 161 (see FIG. 1) by being connected to the backplane 121 (see FIG. 1) and each server module 10.

Here, the supply hole 4a and the connection part 114a are preferably formed at a higher position than the discharge hole 4b and the connection part 114b. The reason is that the potential energy of the coolant 2 can be used to efficiently send the coolant 2 to the inside of the cooling jacket 12 (see FIGS. 4 and 5) described later.

It should be noted that the inside of each server module 10 is kept in a hermetically sealed state other than the surface provided with the supply hole 4a and the discharge hole 4b (hereinafter referred to as “connection surface”).

<Configuration of server module>
Hereinafter, the configuration of the server module 10 will be described with reference to FIGS. FIG. 3 is a perspective view illustrating a schematic configuration of the server module 10. FIG. 4 is a perspective sectional view showing a schematic configuration of the server module 10. FIG. 5 is a diagram illustrating a state of the server module 10 when the server apparatus 1 is in operation.

First, the external configuration of the server module 10 will be described with reference to FIG.
As shown in FIG. 3, the server module 10 includes a housing 11 and a cooling jacket 12.

The housing 11 is configured as a sealed container that houses a circuit board 21 (see FIG. 4) on which electronic devices such as a CPU and a memory are mounted. Hereinafter, the housing 11 is referred to as “sealed container 11”.

The cooling jacket 12 is a member that allows the coolant 2 to flow around the electronic device. The cooling jacket 12 includes a flow path 13 for the cooling liquid 2 including a cooling liquid supply path 13a and a cooling liquid discharge path 13b. The flow path 13 has a configuration in which a plurality of folds are made inside the cooling jacket 12, and as a result, has a configuration shown in FIG.

The cooling jacket 12 is in direct contact with the circuit board 21 (see FIG. 4) accommodated in the sealed container 11, or the vapor of the coolant 2, the heat transfer sheet, and other heat conduction. You may comprise so that the heat which generate | occur | produces with the electronic device mounted in the circuit board 21 may be conducted to the cooling fluid 2 by contacting indirectly through a means.

As shown in FIG. 3, the server module 10 is preferably provided with a positioning guide 19. The positioning guide 19 is a member that positions the server module 10 in the 1U server 3. In the example shown in FIG. 3, the positioning guide 19 is provided in the upper part of the cooling jacket 12 and the lower part of the sealed container 11, and is configured to position the server module 10 in the horizontal direction in the 1U server 3. ing.

Next, the internal configuration of the server module 10 will be described with reference to FIG. FIG. 4 shows the configuration of the server module 10 in a state cut along the cutting plane CT2 shown in FIG.

As shown in FIG. 4, the server module 10 includes a condensation fin 15, a support member 18, and a circuit board 21 inside.

The condensing fin 15 is a member that cools and condenses the inert refrigerant 31 (see FIG. 5) that is vaporized by heat generated by the heat generating member 22 (mainly the high heat generating member 22a) described later.
The support member 18 is a member that supports the circuit board 21 in the horizontal direction inside the sealed container 11.
The circuit board 21 is a member on which electronic devices such as a CPU and a memory are mounted.

The condensation fins 15 are provided at the lower part of the cooling jacket 12 and are provided so as to protrude from the cooling jacket 12 to a cooling unit 17 described later. The condensation fins 15 are thermally connected to the flow path 13 provided inside the cooling jacket 12. The condensing fin 15 forms the condensing part 14 which cools and condenses the inert refrigerant 31 evaporated by boiling together with the flow path 13.

The cooling unit 17 is a space provided inside the hermetic container 11 in order to immerse a heat radiating member 23 described later in an insulating inert refrigerant 31 (see FIG. 5) in a liquid phase state. The cooling unit 17 has an upper surface sealed by the cooling jacket 12, a side surface sealed by the side wall of the sealed container 11, and a lower surface sealed by the support member 18 and the circuit board 21.

The inside of the cooling unit 17 contains an inert refrigerant 31 (see FIG. 5). In the present embodiment, description will be made assuming that, for example, HFE7000 (registered trademark) manufactured by 3M is used as the inert refrigerant 31. In the present embodiment, the liquid-phase inert refrigerant 31 has a liquid surface height position that is at least higher than the position of the boiling heat transfer surface 24 of the heat radiating member 23 described later, and the lower end of the condensing fin 15. It demonstrates as what is put in the inside of the cooling part 17 so that it may become lower than this position.

The circuit board 21 has one surface (the lower surface in the example shown in FIG. 5) as a mounting surface for the high heat generating member 22a and the low heat generating member 22b, and the other surface (the upper surface in the example shown in FIG. 5). This is the mounting surface of the heat dissipation member 23.

The high heat generating member 22a is, for example, an electronic device such as a CPU. The low heat generating member 22b is, for example, an electronic device such as a memory. Hereinafter, the high heat generating member 22a and the low heat generating member 22b are collectively referred to as “heat generating member 22”.

The heat radiating member 23 is a member that conducts heat generated by the heat generating member 22 (mainly, the high heat generating member 22a) to the liquid state inert refrigerant 31 (see FIG. 5) to dissipate heat. The heat radiating member 23 has a boiling heat transfer surface 24 on the upper surface for efficiently conducting heat to the liquid state inert refrigerant 31 and boiling the inert refrigerant 31.

The surface of the circuit board 21 opposite to the mounting surface (the lower surface in the example shown in FIG. 5) of the circuit board 21 so that the heat radiating member 23 faces the heat generating member 22 (mainly the high heat generating member 22a). (In the example shown in FIG. 5, it is mounted on the upper surface). The heat dissipating member 23 is configured such that the mounting area is larger than the mounting area of the high heat generating member 22 a connected to the heat dissipating member 23.

The circuit board 21 includes a thermal via 25 inside. The thermal via 25 is a via that thermally connects the heat generating member 22 (mainly the high heat generating member 22 a) and the heat radiating member 23. The thermal via 25 is a material having high thermal conductivity (for example, copper or the like) by insulating the inside of the hole having the same shape as the

conductive vias

217a and 217b (see FIG. 7C) for conducting the circuit board 21. The metal material) is filled.

<Status of server module when server device is running>
Next, the state of the server module 10 when the server apparatus 1 is in operation will be described with reference to FIG.

As shown in FIG. 5, when the server device 1 operates, the server module 10 generates heat generated by the heat generating member 22 (mainly the high heat generating member 22 a) mounted on the lower surface via the thermal via 25. Conducted to the heat dissipating member 23 mounted on. Then, the heat radiating member 23 conducts heat to the inert refrigerant 31 in a liquid phase state on the boiling heat transfer surface 24, and causes the inert refrigerant 31 to boil.

The inert refrigerant 31 evaporates by boiling (that is, changes to a gas phase state) and rises as a vapor. As a result, the vaporized inert refrigerant 31 comes into contact with the condensation fins 15.

The condensation fins 15 are cooled to a certain temperature or less by the coolant 2 flowing inside the flow path 3. Therefore, the vaporized inert refrigerant 31 is cooled by the condensation fins 15. As a result, the inert refrigerant 31 is liquefied by cooling (that is, changed to a liquid phase state), becomes a liquid, and descends.

The condensation fin 15 absorbs heat when cooling the inert refrigerant 31 and conducts the heat to the coolant 2 flowing inside the flow path 13. As a result, the server module 10 releases the heat generated by the heat generating member 22 (mainly the high heat generating member 22a) to the outside.

Since such a server module 10 uses the heat of vaporization and the heat of condensation caused by the phase change of the inert refrigerant 31 to release heat to the outside, the heat generating member 22 (mainly the high heat generating member 22a) is cooled. High cooling performance can be obtained.

<Circuit board manufacturing method>
Hereinafter, a method for manufacturing the circuit board 21 will be described with reference to FIGS. 6 and 7 are diagrams showing an example of a method for manufacturing the circuit board 21.

FIG. 6 shows a manufacturing process until a substrate 219 (see FIG. 6 (i)) in the lower portion of the circuit board 21 is formed. FIG. 7 shows a manufacturing process from the formation of the substrate 231 (see FIG. 7A) in the upper portion of the circuit board 21 to the formation of the final circuit board 21 (see FIG. 7C). ing.

In the first embodiment, the lower portion of the substrate 219 (see FIG. 6 (i)) is a substrate (interposer) in which an electrode is formed on an insulating layer. Hereinafter, the substrate 219 in the lower part is referred to as an “interposer 219”. The upper portion substrate 231 (see FIG. 7A) is a substrate formed by laminating a resin material layer and a copper layer. Hereinafter, the upper substrate 231 is referred to as a “resin substrate 231”.

Here, the case where the interposer 219 is formed as a glass interposer by using the silicon glass paste 211 (see FIG. 6A) will be described. However, the interposer 219 may be formed using a hard and insulating material (for example, a material such as ceramic) other than the silicon glass paste 211.

First, as shown in FIG. 6A, a silicon glass paste 211 constituting an insulating layer is prepared, and a resist 213 is applied to the surface of the silicon glass paste 211 as shown in FIG. 6B.

Next, as shown in FIG. 6C, a mask (not shown) formed in a circuit shape is formed on the resist 213, and ultraviolet rays are irradiated onto the resist 213 through the mask. As a result, the resist 213a in the region irradiated with ultraviolet light is cured, while the resist 213b in the region not irradiated with ultraviolet light is not cured.

Hereinafter, the resist 213a is referred to as “cured resist 213a” and the resist 213b is referred to as “non-cured resist 213b”. The “non-cured resist 213b” functions as a mask pattern when a circuit is formed by the copper plating 215 in the step shown in FIG.

Next, as shown in FIG. 6D, the cured resist 213a is selectively removed using a developer, and a mask pattern is formed by the remaining non-cured resist 213b.

Next, as shown in FIG. 6E, a copper plating 215 is applied to the substrate through the non-cured resist 213b to form a circuit, and then a solvent is used as shown in FIG. 6F. The uncured resist 213b is removed. Thus, an insulating substrate 216 having a circuit formed on the surface is formed.

Thereafter, a plurality of insulating substrates 216 are formed by repeating the same steps as in FIGS. 6A to 6F.

Next, as shown in FIG. 6G, a plurality of insulating substrates 216 formed by repeating the same steps as in FIGS. 6A to 6F are stacked and baked. As a result, the laminated substrate 218 constituting the basic portion of the interposer 219 is formed.

Next, as shown in FIG. 6H, conductive vias 217a and thermal vias 25a penetrating part or all of the multilayer substrate 218 are formed, and copper is filled in the conductive vias 217a and thermal vias 25a. Thereby, an interposer 219 is formed. Note that the number N of thermal vias 25a (where N is an integer) is larger than the number M (where M is an integer) of thermal vias 25b (see FIG. 7A) described later.

Next, as shown in FIG. 6 (i), the heat generating member 22 (22 a, 22 b) is mounted on the interposer 219. At this time, mounting is performed using a solder bump pad (hereinafter simply referred to as “solder bump”) 221 a having a relatively high melting point. For example, the high heat generating member 22a is bonded to the conductive via 217a and the thermal via 25a with the solder bump 221a, and the low heat generating member 22b is bonded to the conductive via 217a with the solder bump 221a.

The solder bump 221a is formed to have a diameter smaller than the diameter of a solder bump 221b (see FIG. 7B) described later. Here, the description will be made assuming that the joining of the members using the solder material including the solder bumps 221a is performed by passing the substrate through a reflow furnace (not shown) (hereinafter the same).

After the step shown in FIG. 6 (i), the same steps as in FIG. 6 (a) to FIG. 6 (h) are performed as in the case of forming the interposer 219 using a resin instead of the silicon glass paste 211. As a result, a resin substrate 231 is formed as shown in FIG.

However, in the first embodiment, at that time, for example, an intermediate layer 235 having a heat transfer member 233 made of a metal material such as copper is formed on the lower surface of the resin substrate 231. Here, the case where the heat transfer member 233 is a copper plate will be described. Hereinafter, the heat transfer member 233 may be referred to as a “copper plate 233”. The position of the copper plate 233 is a position facing the heat dissipation member 23 on the lower surface side of the resin substrate 231. The reason for forming the intermediate layer 235 will be described later.

Thereafter, conductive vias 217b and thermal vias 25b penetrating part or all of the resin substrate 231 are formed, and the conductive vias 217b and thermal vias 25b are filled with copper. The thermal via 25 b is connected to the copper plate 233. In the present embodiment, the thermal via 25b is formed to have a larger diameter than the thermal via 25a in accordance with the diameter of the solder bumps 221a and 221b.

Next, as shown in FIG. 7B, the heat radiating member 23 is mounted on the resin substrate 231. At this time, the solder bumps 221b having a relatively high melting point are used for mounting. For example, the heat radiating member 23 is joined to the thermal via 25b with the solder bump 221b.

Note that the manufacturing process of the resin substrate 231 (the process of FIGS. 7A to 7B) is performed before the manufacturing process of the interposer 219 (the process of FIGS. 6A to 6I). It doesn't matter. Further, the manufacturing process of the resin substrate 231 (the process of FIGS. 7A to 7B) is not necessarily separate from the manufacturing process of the interposer 219 (the process of FIGS. 6A to 6I). It is not necessary to carry out in a line and a separate process, and it may be carried out simultaneously on the same line.

Next, as shown in FIG. 7 (c), the interposer 219 formed in the step of FIG. 6 (i) and the resin substrate 231 formed in the step of FIG. 7 (b) are joined. As shown in FIG. 7C, the interposer 219 is disposed so as to be inverted in the vertical direction, and the resin substrate 231 is bonded thereon. Thereby, the circuit board 21 is formed.

The bonding between the interposer 219 and the resin substrate 231 is performed using a solder bump 221c having a relatively low melting point. For example, the interposer 219 is arranged upside down, and the thermal via 25a formed in the interposer 219 and the copper plate 233 formed in the resin substrate 231 are joined by a solder bump 221c having a relatively low melting point.

The interposer 219 and the resin substrate 231 are preferably joined by passing the circuit board 21 through a line in which the temperature of the reflow furnace is adjusted to a temperature at which only the solder bumps 221c having a relatively low melting point are melted. good. As a result, among the solder bumps 211a, 211b, and 221c (hereinafter collectively referred to as “solder bump 211”), only the solder bump 221c having a relatively low melting point is melted, and the solder bump having a relatively high melting point is melted. Since 221a and 211b are not melted, the interposer 219 and the resin substrate 231 can be bonded while the bonded state of the heat generating member 22 and the heat radiating member 23 is maintained.

Here, the reason why the intermediate layer 235 is formed in the step shown in FIG.
For example, the circuit board 21 is required to mount heat generating members 22 such as a CPU and a memory on the interposer 219 with high density. In order to satisfy this demand, the circuit board 21 preferably forms the thermal vias 25 a of the interposer 219 with a smaller diameter and a smaller pitch than the thermal vias 25 b of the resin substrate 231. For this reason, the thermal via 25a of the interposer 219 and the thermal via 25b of the resin substrate 231 are formed in sizes having different diameters and minimum pitches. As a result, the circuit board 21 is difficult to bond the thermal via 25a and the thermal via 25b, and it is difficult to conduct heat between the

thermal vias

25a and 25b.

Therefore, in the first embodiment, the circuit board 21 has an intermediate layer 235 having a copper plate 233 as a heat transfer member formed on the lower surface of the resin substrate 231. As a result, the circuit board 21 facilitates the bonding between the thermal via 25a and the thermal via 25b so that heat can be efficiently conducted between the

thermal vias

25a and 25b.

<Main features of server device and server module>
Hereinafter, main features of the server device 1 according to the first embodiment will be described.
(1) As shown in FIG. 1, the server device 1 is connected to a plurality of server modules 10, a rack cabinet 110 that houses the plurality of server modules 10 therein, and a chiller 164 that cools the coolant 2. A coolant circulation path 161 that circulates the liquid 2 between the plurality of server modules 10 and the chiller 164 is provided.

The coolant circulation path 161 is disposed so as to be connected in parallel to each of the plurality of server modules 10 through the back plane 121 disposed in the center of the rack cabinet 110. The coolant circulation path 161 is a portion (that is, the coolant supply pipe 161Aa and the coolant that is connected to the server module 10 (that is, the coolant supply pipe 161Ab and the coolant discharge pipe 161Bb) passes through the backplane 121. The discharge pipe 161Ba) is configured so as to be contactable and separable.

In such a server device 1, the coolant supply pipe 161 Ab and the coolant discharge pipe 161 Bb provided in the guide rail 113 are connected to the supply hole 4 a and the discharge hole 4 b provided in the connection surface of each server module 10. By doing so, the coolant 2 can be supplied to and discharged from each server module 10 while keeping the sealed state inside each server module 10.

(2) As shown in FIG. 5, the server device 1 is mounted on one surface and the other surface so that the heat generating member 22 (mainly the high heat generating member 22a) and the heat radiating member 23 face each other. A server module 10 having a circuit board 21 and a sealed container 11 that accommodates the circuit board 21 therein is used. The circuit board 21 includes a plurality of thermal vias 25 that thermally connect the high heat generating member 22a and the heat radiating member 23 inside. Further, the heat radiating member 23 is immersed in an insulating inert refrigerant 31 in a liquid phase state inside the sealed container 11.

In such a server device 1, since the high heat generating member 22 a and the heat radiating member 23 are separately mounted on one surface and the other surface of the circuit board 21, the high heat generating member 22 a is mounted with high density. Can do. Further, since the server device 1 mounts the heat radiating member 23 in an empty space on the other surface of the circuit board 21 where the high heat generating member 22a is not mounted, the heat radiating member having a larger mounting area than the mounting area of the high heat generating member 22a. 23 can be mounted on the circuit board 21, and as a result, a high cooling performance for cooling the high heat generating member 22a can be obtained. Moreover, since the server device 1 thermally connects the high heat generating member 22a and the heat radiating member 23 with the thermal via 25, and the heat radiating member 23 is immersed in the insulating inert refrigerant 31 in a liquid phase state, Also by this, high cooling performance can be obtained.

That is, the server device 1 conducts the heat generated by the heat generating member 22 (mainly the high heat generating member 22a) to the heat radiating member 23 through the thermal via 25, and the conducted heat is transferred from the heat radiating member 23 to the liquid phase state. Conducted to the inert refrigerant 31. Then, the server device 1 causes the condensation fins 15 to absorb the heat of the inert refrigerant 31, and conducts the absorbed heat from the condensation fins 15 to the coolant 2 flowing inside the flow passage 13. Such a server device 1 uses the heat of vaporization and the heat of condensation caused by the phase change of the inert refrigerant 31 to release heat to the outside, so that the heat generating member 22 (mainly the high heat generating member 22a) is cooled. High cooling performance can be obtained.

In addition, since the heat generating member 22 and the heat radiating member 23 are mounted on different surfaces of the circuit board 21, the server device 1 can mount the heat generating member 22 with high density. Further, since the server device 1 can mount the heat dissipating member 23 having a relatively large mounting area (for example, the heat dissipating member 23 having a mounting area wider than the mounting area of the high heat generating member 22a), high cooling performance can be obtained. Can do. Therefore, the server device 1 can achieve both mounting the heat generating members at high density and obtaining a high cooling performance for cooling the heat generating members 22 (mainly the high heat generating members 22a).

(3) As shown in FIG. 5, in the first embodiment, the heat radiating member 23 conducts heat generated by the high heat generating member 22 a to the inert refrigerant 31 to boil the inert refrigerant 31. 24. The circuit board 21 is housed inside the sealed container 11 with the one surface on which the high heat generating member 22a is mounted as the lower surface and the other surface on which the heat dissipation member 23 is mounted as the upper surface. The sealed container 11 includes a condensing unit 14 that is thermally connected to the outside and cools and condenses the inert refrigerant 31 vaporized by boiling above the circuit board 21.

In such a server device 1, since the condensing unit 14 cools the inert refrigerant 31 where the vaporized inert refrigerant 31 flows, the inert refrigerant 31 can be efficiently cooled and condensed.

(4) As shown in FIG. 5, the heat dissipating member 23 is configured such that the mounting area is larger than the mounting area of the high heat generating member 22 a connected to the heat dissipating member 23.
In such a server device 1, since the mounting area of the heat radiating member 23 is larger than the mounting area of the high heat generating member 22a, the heat generated by the high heat generating member 22a can be efficiently released, and the heat generating member 22 (mainly High cooling performance for cooling the high heat generating member 22a) can be obtained.

(5) As shown in FIG. 5, in the first embodiment, the condensing unit 14 is configured by a cooling jacket 12 that includes therein a flow path 13 through which the coolant 2 flows. The condensing unit 14 includes a condensing fin 15 that is thermally connected to the flow path 13 and cools and condenses the inert refrigerant 31 vaporized by boiling. The condensation fins 15 are provided so as to protrude from the cooling jacket 12 into a space (cooling part) 17 in which the heat radiating member 23 inside the sealed container 11 is immersed in the inert refrigerant 31.

Such a server device 1 can efficiently condense the inert refrigerant 31 vaporized by boiling with the condensation fins 15. Thereby, the server apparatus 1 can obtain the high condensation performance of the inert refrigerant 31, and thus can obtain high cooling performance for cooling the heat generating member 22 (mainly the high heat generating member 22a).

(6) As shown in FIGS. 6 and 7, the server device 1 includes a circuit board 21 in which two or more layers of a resin substrate 231 and an insulating substrate are stacked, and high heat generation mounted on one surface of the circuit board 21. The member 22a, the heat dissipating member 23 mounted on the other surface of the circuit board 21 facing the high heat generating member 22a, and the heat generating member 22a and the heat dissipating member 23 formed in the circuit board 21 are thermally The server module 10 having a plurality of thermal vias 25 connected to is used.

The thermal via 25 connects the high heat generating member 22a and the heat radiating member 23 through the heat transfer member (copper plate) 233 disposed inside the circuit board 21 to an N to M relationship (N> M) ( However, N and M are both integers). Further, the high heat generating member 22a and the thermal via 25 and the heat radiating member 23 and the thermal via 25 are joined by solder materials (solder bumps 221a and 221b), respectively. Also, the solder material (solder bump 221b) that joins between the heat dissipation member 23 and the thermal via 25 has a larger diameter than the solder material (solder bump 221a) that joins between the high heat generating member 22a and the thermal via 25. Is formed.

In other words, the server device 1 has the following configuration.
The circuit board 21 and the high heat generating member 22a are joined by a solder material (solder bump 221a). The circuit board 21 and the heat radiating member 23 are joined by a solder material (solder bump 221b) having a diameter different from that of the one surface on which the high heat generating member 22a is mounted. The server device 1 includes a plurality of solder materials (solders) each having a thermal via 25 formed on one surface of the circuit board 21 via a heat transfer member (copper plate) 233 disposed inside the circuit board 21. In addition to being connected to the bump 221a), it is connected to one large solder material (solder bump 221b) formed on the other surface of the circuit board 21, and heat generated on one surface of the circuit board 21 is generated. The heat can be conducted to the heat radiating member 23 mounted on the other surface of the circuit board 21 and discharged from the heat radiating member 23.

In such a configuration, the server device 1 mounts the high heat generating member 22a and the heat radiating member 23 separately on one surface and the other surface of the circuit board 21, so that the high heat generating member 22a is mounted with high density. be able to. Further, since the server device 1 mounts the heat radiating member 23 in the empty space on the other surface of the circuit board 21 on which the high heat generating member 22a is not mounted, the heat radiating member having a larger mounting area than the mounting area of the high heat generating member 22a. 23 can be mounted on the circuit board 21, and as a result, a high cooling performance for cooling the heat generating member 22 (mainly the high heat generating member 22a) can be obtained. In the server device 1, the solder bump 221 b that joins between the heat dissipation member 23 and the thermal via 25 b is formed to have a larger diameter than the solder bump 221 a that joins between the high heat generating member 22 a and the thermal via 25 a. For this reason, the heat dissipation member 23 having a larger mounting area than the mounting area of the high heat generating member 22a can be efficiently mounted on the circuit board 21 and the heat conduction efficiency can be increased. As a result, high cooling performance can be obtained. be able to.

(7) The thermal via 25b connected to the heat radiating member 23 and the thermal via 25a connected to the high heat generating member 22a are connected to the heat radiating member 23 in accordance with the diameter of the solder material (

solder bumps

221a, 221b) to be connected. The connected thermal via 25b is formed with a larger diameter than the thermal via 25a connected to the high heat generating member 22a. The circuit board 21 includes an intermediate layer 235 that connects the thermal via 25 connected to the high heat generating member 22 a and the thermal via 25 connected to the heat radiating member 23 inside.

The server device 1 has different diameters because the intermediate layer 235 is interposed between the thermal via 25a having a small diameter connected to the high heat generating member 22a and the thermal via 25b having a large diameter connected to the heat radiating member 23. The

thermal vias

25a and 25b can be connected to each other.

As described above, according to the server device 1 according to the first embodiment, by using the server module 10, the heat generating member 22 is mounted with high density and the heat generating member 22 (mainly the high heat generating member 22a) is cooled. It is possible to achieve both high cooling performance for achieving the above.

[Embodiment 2]
Next, Embodiment 2 will be described. In the server module 10 according to the first embodiment, the high heat generating member 22a and the heat radiating member 23 are connected by a plurality of relatively small diameter thermal vias 25 (see FIG. 5).

In contrast, the second embodiment provides a server module 10A having a configuration in which some or all of the plurality of thermal vias 25 are integrated into a single high heat transfer member 26 (see FIG. 8).

Hereinafter, the configuration of the server module 10A according to the second embodiment will be described with reference to FIG. FIG. 8 is a diagram illustrating a schematic configuration of a server module 10A according to the second embodiment.

As shown in FIG. 8, the server module 10 A according to the second embodiment is compared with the server module 10 according to the first embodiment (see FIG. 5), instead of the plurality of thermal vias 25 in the circuit board 21. The difference is that a single member having high thermal conductivity (hereinafter referred to as a “high heat transfer member”) is provided.

The high heat transfer member 26 is a member having high thermal conductivity. The high heat transfer member 26 is made of a metal material such as copper, for example. The high heat transfer member 26 has a larger diameter than the thermal via 25 of the server module 10 according to the first embodiment.

The server module 10A according to the second embodiment performs heat conduction between the high heat generating member 22a and the heat radiating member 23 by the high heat transfer member 26 having a larger diameter (that is, wider cross-sectional area) than the thermal via 25. Therefore, the server module 10A can ensure a larger heat conduction area than the server module 10 according to the first embodiment. Thereby, the server module 10A can obtain higher cooling performance than the server module 10 according to the first embodiment.

In the example shown in FIG. 8, the high heat transfer member 26 has a configuration in which the cross-sectional area gradually increases along the thickness direction of the resin substrate 231 from the high heat generation member 22 a side toward the heat dissipation member 23 side. ing. That is, the high heat transfer member 26 is formed so that the cross-sectional area on the heat radiating member 23 side is wider than the cross-sectional area on the high heat generating member 22a side. Thereby, the server module 10A can mount the heat radiating member 23 having a surface area larger than the mounting area of the high heat generating member 22a. As a result, the server module 10 A can ensure a relatively wide heat conduction area between the high heat generating member 22 a and the heat radiating member 23. As a result, the server module 10A can obtain higher cooling performance.

In general, in the circuit board 21, the signal lines of the high heat generating member 22a are arranged densely in the outer frame portion of the mounting region of the high heat generating member 22a, and the circuit board 21 tends not to be arranged in the central portion of the mounting region of the high heat generating member 22a. It is in. Therefore, the circuit board 21 can secure a free space in the central portion of the mounting region of the high heat generating member 22a relatively easily. Therefore, the server module 10 A according to the second embodiment may be configured such that the high heat transfer member 26 is disposed near the central portion of the mounting area of the circuit board 21 using the characteristics of the circuit board 21. In this case, since the server module 10A can ensure a relatively wide heat conduction area, it is possible to obtain higher cooling performance.

Further, the server module 10A may be configured such that the signal line of the high heat generating member 22a is connected to the heat radiating member 23 after the insulation process is performed on the signal line of the high heat generating member 22a. In this case, the server module 10 A can use the signal line of the high heat generating member 22 a as a pseudo thermal via, and therefore can obtain higher cooling performance.

Further, the server module 10A may be configured such that the GND line of the power line of the high heat generating member 22a is connected to the heat radiating member 23. In this case, since the server module 10A can use the GND line as a pseudo thermal via, it is possible to obtain higher cooling performance.

<Circuit board manufacturing method>
Hereinafter, a method for manufacturing the circuit board 21A incorporated in the server module 10A will be described with reference to FIG. FIG. 9 is a diagram illustrating an example of a method for manufacturing the circuit board 21A according to the second embodiment.

Here, the interposer 219 (the interposer 219 in a state where the heat generating member 22 is mounted) is formed by the steps shown in FIGS. 6A to 6I, and the step shown in FIG. Therefore, it is assumed that the resin substrate 231 (the resin substrate 231 in a state where the heat dissipation member 23 is not mounted) is formed.

After the resin substrate 231 is formed by the process of FIG. 7A, as shown in FIG. 9A, the opening 238 is penetrated from the upper surface to the lower surface of the resin substrate 231 using a punching machine or the like. Form.

In the example shown in FIG. 9A, the opening 238 is formed to be inclined in the oblique direction with respect to the upper surface of the resin substrate 231. That is, the opening 238 is formed so that the cross-sectional area gradually increases along the thickness direction of the resin substrate 231 from the lower surface side (high heat generating member 22a side) to the upper surface side (heat radiating member 23 side). ing.

Next, the insulating material 241 is disposed along the slope of the opening 238, and the high heat transfer member 26 is filled in the opening 238. In order to fix the high heat transfer member 26 to the resin substrate 231, a mask (not shown) is formed on the resin substrate 231, and fixing processing 239 such as plating is performed on the resin substrate 231. Thereby, the high heat transfer member 26 is fixed to the resin substrate 231.

The reason why the insulating material 241 is disposed is that the opening 238 is formed to be inclined by a punch or the like, and the signal line may be short-circuited on the inclined surface of the opening 238 (particularly in the vicinity of the heat dissipation member 23). There is to prevent it.

Next, the solder 222a having a relatively high melting point and a relatively large amount is disposed on the high heat transfer member 26 of the resin substrate 231. Then, the resin substrate 231 is passed through a reflow furnace. Thus, the heat radiating member 23 is joined to the high heat transfer member 26 of the resin substrate 231 by the solder 222a.

Next, a solder bump 221c having a relatively low melting point is disposed on the conductive via 217a of the interposer 219, and a solder 222b having a relatively low melting point and less than the solder 222a is disposed on the thermal via 25a of the interposer 219. Further, the resin substrate 231 is disposed on the interposer 219. Then, the resin substrate 231 and the interposer 219 are passed through a reflow furnace.

9B, the conductive via 217b, the interposer 219, and the conductive via 217a of the resin substrate 231 are joined by the solder bump 221c, and the high heat transfer member 26 of the resin substrate 231 is bonded by the solder 222b. The interposer 219 and the thermal via 25a are joined. As a result, the circuit board 21A is formed.

Since the server module 10A including the circuit board 21A formed in this way can ensure a relatively wide heat conduction area between the high heat generating member 22a and the heat radiating member 23, the server module according to the first embodiment. Cooling performance higher than 10 can be obtained.

The high heat transfer member 26 can be configured to have the same cross-sectional area with respect to the thickness direction of the resin substrate 231 as shown in FIG. Hereinafter, a method for manufacturing the circuit board 21Aa including the high heat transfer member 26 configured as described above will be described with reference to FIG. FIG. 10 is a diagram illustrating an example of a method for manufacturing the circuit board 21Aa according to the modification of the second embodiment.

After the resin substrate 231 is formed by the process of FIG. 7A, as shown in FIG. 10A, the opening 238a is penetrated from the upper surface to the lower surface of the resin substrate 231 using a punching machine or the like. Form.

In the example shown in FIG. 10A, the opening 238a is formed in the vertical direction with respect to the upper surface of the resin substrate 231. That is, the opening 238 is formed to have the same cross-sectional area with respect to the thickness direction of the resin substrate 231.

Next, the high heat transfer member 26 is filled in the opening 238. At this time, similarly to the circuit board 21A of the server module 10A, the insulating material 241 may be disposed along the side wall surface of the opening 238a, and the high heat transfer member 26 may be filled in the opening 238. In order to fix the high heat transfer member 26 to the resin substrate 231, a mask (not shown) is formed on the resin substrate 231, and fixing processing 239 such as plating is performed on the resin substrate 231. Thereby, the high heat transfer member 26 is fixed to the resin substrate 231.

Hereinafter, the same processing as the circuit board 21A of the server module 10A is performed. That is, the solder 222a having a relatively high melting point and a relatively large amount is disposed on the high heat transfer member 26 of the resin substrate 231, and the resin substrate 231 is passed through a reflow furnace. Next, the solder bump 221c is disposed on the conductive via 217a of the interposer 219, the solder 222b is disposed on the thermal via 25a of the interposer 219, and the resin substrate 231 is disposed on the interposer 219. The resin substrate 231 and the interposer 219 are passed through a reflow furnace. As a result, the circuit board 21Aa is formed.

The circuit board 21Aa thus formed is not as high as the circuit board 21A, but as with the circuit board 21A, a relatively wide heat conduction area is ensured between the high heat generating member 22a and the heat radiating member 23. Therefore, higher cooling performance than the server module 10 according to the first embodiment can be obtained.

As described above, according to the second embodiment, by using the server module 10A, the heat generating member 22 is mounted at a high density and the heat generating member 22 (mainly the high heat generating member 22a) as in the first embodiment. It is possible to achieve both high cooling performance for cooling the battery.
Moreover, according to the second embodiment, a higher cooling performance than that of the first embodiment can be obtained.

[Embodiment 3]
Next, Embodiment 3 will be described. In the server module 10 according to the first embodiment, the heat generated in the high heat generating member 22a is conducted to the inert refrigerant 31 by immersing the heat radiating member 23 in the inert refrigerant 31 (see FIG. 5).

In contrast, the third embodiment provides a server module 10B that conducts heat generated in the high heat generating member 22a into the air (see FIG. 11).

Hereinafter, the configuration of the server module 10B according to the third embodiment will be described with reference to FIG. FIG. 11 is a diagram illustrating a schematic configuration of a server module 10B according to the third embodiment.

As shown in FIG. 11, the server module 10 B according to the third embodiment includes a heat radiating member 23 B instead of the heat radiating member 23 compared to the server module 10 according to the first embodiment (see FIG. 5), and The heat dissipating member 23B is different from the air disposing member 23B in the air.

The heat dissipating member 23B is a member that conducts heat generated in the high heat generating member 22a from the surface exposed to the outside (hereinafter simply referred to as “exposed surface”) to the air. The heat radiating member 23B is thermally connected to the high heat generating member 22a by the thermal via 25.

When the heat is generated, the high heat generating member 22a conducts the heat to the heat radiating member 23B through the thermal via 25. The heat radiating member 23B conducts the conducted heat from the exposed surface to the air. Thereby, the server module 10B can obtain high cooling performance for cooling the heat generating member 22 (mainly the high heat generating member 22a).

The heat dissipating member 23B may conduct heat into the air by natural convection.
Further, for example, as shown in FIG. 11, the heat dissipating member 23 B may be configured to include fins 43 (or portions that increase the surface area similar to the fins 43) on the exposed surface. In this case, since the heat dissipation member 23B increases the heat dissipation area, the heat dissipation performance can be improved.

Further, for example, as shown in FIG. 11, the server module 10 B may include a blower 41 that supplies air, an inert refrigerant 31, or the like as cooling air 44 to the heat radiating member 23 B. In this case, since the server module 10B conducts heat into the air by forced convection, the server module 10B can obtain higher heat dissipation performance than when heat is conducted into the air by natural convection. The server module 10B is provided with an opening 42 for allowing the cooling air 44 to flow. The cooling air 44 passes through the opening 42 and is discharged to the outside of the server module 10B.

As described above, according to the third embodiment, by using the server module 10B, similarly to the first embodiment, the heat generating member 22 is mounted with high density and the heat generating member 22 (mainly the high heat generating member 22a). It is possible to achieve both high cooling performance for cooling the battery.

[Embodiment 4]
Next, a fourth embodiment will be described. In the server module 10 according to the first embodiment, the heat generated in the high heat generating member 22a is conducted to the inert refrigerant 31 by immersing the heat radiating member 23 in the inert refrigerant 31 (see FIG. 5).

On the other hand, in the fourth embodiment, the server module 10C that conducts the heat generated in the high heat generating member 22a to the coolant 2 by bringing the heat dissipation member 23C into contact with or close to the piping through which the coolant 2 flows. Provided (see FIG. 12).

Hereinafter, the configuration of the server module 10C according to the fourth embodiment will be described with reference to FIG. FIG. 12 is a diagram illustrating a schematic configuration of a server module 10C according to the fourth embodiment.

As shown in FIG. 12, the server module 10 C according to the fourth embodiment includes a coolant pipe 311 through which the coolant 2 flows, as compared with the server module 10 according to the first embodiment (see FIG. 5). And a point that a heat radiating member 23 C is provided instead of the heat radiating member 23.

The coolant pipe 311 is adjacent to or embedded in the heat dissipation member 23C.
The heat radiating member 23 C is in contact with or close to the wall surface of the coolant pipe 311.

The server apparatus 1 sends the coolant 2 from the outside to the inside of the server module 10C through the coolant pipe 311 by a pump (not shown). The coolant 2 is introduced into the server module 10 C from a pipe inlet 312 provided in the coolant pipe 311, flows inside the coolant pipe 311, and is a pipe outlet provided in the coolant pipe 311. It is discharged from 313 to the outside of the server module 10C.

At that time, the coolant pipe 311 conducts heat from the heat radiating member 23C to the coolant 2 through the wall surface, and discharges heat to the outside of the server module 10C through the coolant 2. As a result, the server module 10C can efficiently discharge the heat generated by the high heat generating member 22a to the outside.

In addition, as shown in FIG. 12, the piping 311 for cooling fluid may be configured such that the heat radiation member 314 for piping is provided on a part or the entire surface thereof. The heat dissipating member 314 for piping is a part that enlarges the surface area of fins or the like. In this case, the coolant pipe 311 absorbs heat from the surrounding space via the pipe heat dissipating member 314 and conducts it to the coolant 2, so that the cooling performance can be improved.

As described above, according to the fourth embodiment, by using the server module 10C, the heat generating member 22 is mounted with high density and the heat generating member 22 (mainly the high heat generating member 22a) as in the first embodiment. It is possible to achieve both high cooling performance for cooling the battery.

[Modification]
The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described. Further, a part of the configuration of an embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of an embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

For example, the server module 10 according to the first embodiment can be modified as shown in FIG. FIG. 13 is a perspective view showing a schematic configuration of the first modification. As shown in FIG. 13, the first modification has a configuration in which the high heat generating member 22 a and the low heat generating member 22 b are mounted on the upper surface of the circuit board 21 together with the heat radiating member 23. The high heat generating member 22a and the low heat generating member 22b mounted on the upper surface of the circuit board 21 are immersed in an inert refrigerant 31 (see FIG. 5) in a liquid phase together with the heat radiating member 23. The first modification can effectively use the unmounted portion of the heat dissipation member 23 on the upper surface of the circuit board 21. Therefore, in the first modification, the heat generating member 22 can be mounted at a higher density than the server module 10 according to the first embodiment.

For example, the server module 10 according to the first embodiment can be modified as shown in FIG. FIG. 14 is a cross-sectional view showing a schematic configuration of the second modification. As shown in FIG. 14, the second modification has a configuration in which the circuit board 21 D is disposed between the circuit board 21 and the condensing unit 14. A high heat generating member 22a, a low heat generating member 22b, and a heat radiating member 23 are mounted on the circuit board 21D. In the example shown in FIG. 14, the high heat generating member 22a and the low heat generating member 22b are mounted on the upper surface of the circuit board 21D, and the heat radiating member 23 is mounted on the lower surface of the circuit board 21D. The entire circuit board 21D is immersed in an inert refrigerant 31 in a liquid phase state. The circuit board 21D is provided with an opening 401 so as not to hinder the flow of the inert refrigerant 31 boiled and vaporized. The second modification can effectively use the space between the circuit board 21 and the condensing unit 14. Therefore, in the second modification, the heat generating member 22 can be mounted at a higher density than the server module 10 according to the first embodiment.

Further, for example, in the server module 10 according to the first embodiment, similarly to the high heat generating member 22a, the low heat generating member 22b and the heat radiating member 23 are connected by the thermal via 25, and the heat generated by the low heat generating member 22b is dissipated. It is also possible to adopt a configuration that conducts to 23 and conducts to the inert refrigerant 31.

Further, for example, the server module 10 according to the first embodiment immerses the high heat generating member 22a in the inert refrigerant 31 in the liquid phase state, so that the heat generated in the high heat generating member 22a is not transmitted from the surface of the high heat generating member 22a. You may make it the structure made to conduct to the active refrigerant | coolant 31 directly.

Further, for example, the server module 10 according to the first embodiment immerses the low heat generating member 22b in the liquid state inert refrigerant 31 in the same manner as the high heat generating member 22a, and generates heat generated in the low heat generating member 22b. You may make it the structure directly conducted to the inert refrigerant | coolant 31 from the surface of the low heat generating member 22b.

Further, for example, the server module 10 according to the first embodiment eliminates the cooling unit 17 and the condensation fins 15 and directly contacts the heat generating member 22 (particularly, the high heat generating member 22a) with the cooling jacket 12, thereby generating the heat generating member. The heat generated at 22 may be conducted to the coolant 2 flowing inside the flow path 13.

Further, for example, the thermal via 25 of the server module 10 according to the first embodiment may be formed by embedding a metal block having high thermal conductivity in the circuit board 21.

In addition, for example, in the server module 10 according to the first embodiment, the inert refrigerant 31 is provided in the cooling unit 17 so that the height position of the liquid level of the inert refrigerant 31 is lower than the position of the lower end portion of the condensation fin 15. It is put inside. That is, the server module 10 is configured so that a space can be formed on the inert refrigerant 31 inside the cooling unit 17. As a result, the server module 10 obtains high cooling performance by releasing heat to the outside using the heat of vaporization and the heat of condensation caused by the phase change of the inert refrigerant 31. However, the phase change of the inert refrigerant 31 may be influenced by the surrounding environment such as atmospheric pressure and temperature. The server module 10 may fill the inside of the cooling unit 17 with the inert refrigerant 31 when it is desired to obtain reliable cooling performance without being affected by atmospheric pressure or the like. In this case, since the server module 10 can increase the heat capacity of the inert refrigerant 31, it is possible to obtain highly reliable heat radiation efficiency without being affected by atmospheric pressure or the like. The server module 10 may fill the cooling unit 17 with a material having thermal conductivity other than the inert refrigerant 31.

For example, the interposer 219 constituting the circuit board 21 according to the first embodiment is formed as a glass interposer. However, the interposer 219 may be formed using a hard and insulating material (for example, a material such as ceramic) other than the silicon glass paste 211.

In addition, for example, the server device 1 according to the first embodiment may be configured to supply the cooling liquid 2 to a cooling target other than the electronic device such as the server module 10.
For example, the server apparatus 1 according to the first embodiment may appropriately change the arrangement of the coolant supply pipes 161Aa and 161Ab and the coolant discharge pipes 161Ba and 161Bb.

In addition, for example, the coolant supply buffer tank 162 and the coolant discharge buffer tank 163 of the server device 1 according to the first embodiment are provided with a space for storing air therein, and when the coolant 2 is introduced from the outside. You may make it the structure which accumulate | stores the air mixed in the inside in the space.

Further, for example, the coolant discharge pipe buffer tank 162 and the coolant discharge buffer tank 163 of the server device 1 according to the first embodiment may be deleted from the rack cabinet 110 and arranged outside the building. In this case, the server device 1 can reduce the weight of the rack cabinet 110.

Further, for example, the rack cabinet 110 of the server device 1 according to the first embodiment may be configured to allow the 1U server 3 to be vertically inserted.
In addition, for example, the guide rail 113 of the server device 1 according to the first embodiment does not need to be fixed to one or both of the rack cabinet 110 and the 1U server 3 and is prepared and attached as an individual component. good.

In addition, for example, the guide rail 113 of the server device 1 according to the first embodiment is partially or entirely replaced with a flow path of the coolant 2 made of a material that is not corroded by the coolant 2 such as a resin. May be.

DESCRIPTION OF SYMBOLS 1 Server apparatus 2 Coolant 3 1U server

4a Supply hole

4b Discharge hole 5

Wiring part

10, 10A, 10B, 10C Server module 11 Case (sealed container)
DESCRIPTION OF SYMBOLS 12 Cooling jacket 13 Flow path 13a Coolant supply path 13b Coolant discharge path 14 Condensing part 15 Condensing fin 17 Cooling part 18 Support member 19

Positioning guide

21, 21A, 21Aa, 21D Circuit board 22 Heat generating member (electronic device)
22a High heat generating member 22b Low

heat generating member

23, 23B, 23C Heat radiating member 24 Boiling

heat transfer surface

25, 25a, 25b Thermal via 26 High heat transfer member 31 Inactive refrigerant 41

Blowing section

42, 238, 238a, 401 Opening 43 Fin 44 Cooling air 110

Rack cabinet

111, 112 Prop 113

Guide rail

114a, 114b Connection part 121 Backplane 160 Cooling system 161 Cooling liquid circulation path 161Aa, 161Ab Cooling liquid supply pipe 161Ba, 161Bb Cooling liquid discharge pipe 162 Cooling liquid supply buffer tank 163 Buffer tank for cooling liquid discharge 164 Chiller (cooling device)
211 Silicone glass paste (insulating layer)
213 Resist 213a Cured resist 213b Non-cured resist (mask pattern)
215 Copper plating 216 Insulating

substrate

217, 217a, 217b Conductive via 218 Laminated substrate 219

Interposer

221, 221a, 221b,

221c Solder bump

222, 222a, 222b Solder (heat transfer member)
231 Resin substrate 233 Copper plate (Heat transfer member)
235 Intermediate layer 239 Fixing process 241 Insulating material 311 Piping for cooling liquid 312 Piping inlet 313 Piping outlet 314 Piping heat dissipation member CT1 Cutting plane CT2 Cutting plane

Claims

A circuit board mounted on one surface and the other surface so that the heat generating member and the heat radiating member face each other;
A sealed container for accommodating the circuit board therein;
The circuit board includes a plurality of thermal vias that thermally connect the heat generating member and the heat radiating member,
The server device, wherein the heat radiating member is immersed in an insulating inert refrigerant in a liquid phase inside the sealed container.
The server device according to claim 1,
The heat dissipating member includes a boiling heat transfer surface that conducts heat generated by the heat generating member to the inert refrigerant to boil the inert refrigerant,
The circuit board is housed inside the sealed container with the one surface on which the heat generating member is mounted as a lower surface and the other surface on which the heat dissipation member is mounted as an upper surface,
The server apparatus, wherein the sealed container is provided with a condensing unit that is thermally connected to the outside and cools and condenses the inert refrigerant vaporized by boiling.
The server device according to claim 2,
The condensing part is constituted by a cooling jacket having a flow path through which a cooling liquid flows, and is condensed to cool and condense the inert refrigerant that is thermally connected to the flow path and vaporized by boiling. With fins,
The server device according to claim 1, wherein the condensing fins are provided so as to protrude from the cooling jacket into a space where the heat radiating member inside the sealed container is immersed in the inert refrigerant.
The server device according to claim 1,
The server device, wherein a mounting area of the heat radiating member is larger than a mounting area of the heat generating member connected to the heat radiating member.
The server device according to claim 1,
The thermal via is connected to the heat generating member and the heat dissipating member through a heat transfer member disposed inside the circuit board so that N> M, where N> M (where N and M are both Integer)
Between the heat generating member and the thermal via and between the heat dissipation member and the thermal via, respectively, are connected by a solder material,
The server apparatus according to claim 1, wherein the solder material connecting the heat radiating member and the thermal via is formed to have a larger diameter than the solder material connecting the heat generating member and the thermal via.
The server device according to claim 1,
A server apparatus, wherein a part or all of the plurality of thermal vias are integrated into a single heat transfer member.
The server device according to claim 6,
The server device, wherein the single heat transfer member is formed such that a cross-sectional area on the heat radiating member side is wider than a cross-sectional area on the heat generating member side.
The server device according to claim 1,
A plurality of server modules containing the circuit board together with the sealed container;
A rack cabinet that houses the plurality of server modules;
A cooling liquid circulation path that is connected to a cooling device that cools the cooling liquid and circulates the cooling liquid between the plurality of server modules and the cooling device;
The coolant circulation path is arranged so as to be connected in parallel to each of the plurality of server modules through a backplane arranged in the center of the rack cabinet, and connected to the server module. A server device, wherein the portion that is made is configured to be movable toward and away from a portion that passes through the backplane.
A circuit board in which two or more layers of a resin substrate and an insulating substrate are laminated;
A heating member mounted on one surface of the circuit board;
A heat dissipating member mounted at a position facing the heat generating member on the other surface of the circuit board;
A plurality of thermal vias formed inside the circuit board and thermally connecting the heat generating member and the heat radiating member;
The thermal via is connected to the heat generating member and the heat dissipating member through a heat transfer member disposed inside the circuit board so that N> M, where N> M (where N and M are both Integer)
Between the heat generating member and the thermal via and between the heat dissipation member and the thermal via, respectively, are connected by a solder material,
The server apparatus according to claim 1, wherein the solder material connecting the heat radiating member and the thermal via is formed to have a larger diameter than the solder material connecting the heat generating member and the thermal via.
The server device according to claim 9, wherein
The thermal via connected to the heat radiating member and the thermal via connected to the heat generating member match the diameter of the solder material to be connected, and the thermal via connected to the heat radiating member is the heat generating member. It is formed in a larger diameter than the thermal via connected to the
The circuit board includes an intermediate layer for connecting the thermal via connected to the heat generating member and the thermal via connected to the heat radiating member inside.
The server device according to claim 9, wherein
A plurality of server modules containing the circuit board;
A rack cabinet that houses the plurality of server modules;
A cooling liquid circulation path that is connected to a cooling device that cools the cooling liquid and circulates the cooling liquid between the plurality of server modules and the cooling device;
The coolant circulation path is arranged so as to be connected in parallel to each of the plurality of server modules through a backplane arranged in the center of the rack cabinet, and connected to the server module. A server device, wherein the portion that is made is configured to be movable toward and away from a portion that passes through the backplane.
The server device according to claim 9, wherein
The server device according to claim 1, wherein the heat dissipating member includes a portion that increases a surface area.
The server device according to claim 12, wherein
Furthermore, it has a ventilation part which ventilates with respect to the said heat radiating member, The server apparatus characterized by the above-mentioned.
The server device according to claim 9, wherein
The server device further includes a coolant pipe through which the coolant flows, in the vicinity of the heat radiating member.
The server device according to claim 9, wherein
A server apparatus, wherein a part or all of the plurality of thermal vias are integrated into a single heat transfer member.