JPH0644598B2 - Electronic circuit mounting method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a large-scale electronic circuit mounting method having high packaging density and high heat generation density.

[Conventional technology]

As a field requiring a large-scale electronic circuit mounting method having a high mounting density and a high heat generation density, there has been a super-large computer. Since the above-mentioned super-large-sized computer has a large-scale function and is required to operate at high speed, the LSI with the highest performance is used, and water cooling or boiling cooling with high heat transport capability is used.

The first conventional example is shown in FIG. In the figure, 1 is a large wiring board, 11 is an LSI chip, 12 is a chip mounting board, 13 is solder for connection, 14 is a terminal, 15 is a heat transfer piston, 16 is a spring, 17 is a heat transfer cylinder, and 18 is a sub board. An envelope, 19 is a water pipe, 20 is cooling water, and 21 is a hose. In the first conventional example having the above-mentioned structure, the heat of the LSI chip 11 is absorbed by the heat transfer piston 15 which can freely expand and contract by the spring 16 and absorb thermal stress, and further, the heat transfer cylinder 17 and the sub-board enclosure 1
8. It is transmitted to the cooling water 20 through the water pipe 19. On the other hand, electrical connection is from the small wiring board 12
It is connected to the large wiring board 1 via 14.

Next, a second conventional example will be described with reference to FIG. In the figure, 6 is a small wiring board, 8 is an LSI package, 22 is a sealed device rack, 23 is a refrigerant, and 24 is a compressor. As the refrigerant, a liquid having a boiling point near the operating temperature of the LSI such as Flohanate and having an electrically insulating property is used. In the second conventional example having the above structure, when the LSI package 8 generates heat, the refrigerant 23 near the LSI package 8 vaporizes, and the vaporization heat at that time cools the LSI. The vaporized refrigerant 23 has its heat removed by the compressor 24, is liquefied, and then returns to the vicinity of the LSI package 8.

[Problems to be solved by the invention]

In the first conventional example, since it is necessary to reduce the thermal resistance between the heat transfer piston and the heat transfer cylinder, the length of the heat transfer piston must be increased, and the overall volume cannot be reduced. Therefore, the heat generation density including the cooling part is 300 W /
It stayed around. In addition, since piping for cooling water hoses is required for each sub-board enclosure, the volume of the above-mentioned piping connection increases, and in the case of water leakage due to poor connection, there is a risk of damaging the electric circuit. In addition, there is a problem in that the hose needs to be attached and detached when the sub-boat enclosure is disconnected for maintenance or the like, which causes a risk of water leakage.

In addition, in the second conventional example, the volume of the bubbles increases as the total heat generation increases, and in particular, a sufficient space is provided at the upper end portion of the small wiring board where the bubbles are concentrated so that the liquid-phase refrigerant contacts the LSI package. There must be. Further, since the volume of the vapor-phase refrigerant is increased by about 5 digits as compared with the liquid phase, a thick conduit is required in the portion leading to the vaporized refrigerant to the compressor. Further, there is a drawback that the compressor itself becomes large and the entire device becomes extremely large. Furthermore, since all parts come into contact with the refrigerant, unless the materials are carefully examined, deterioration due to chemical reaction or the like may occur, and the degree of freedom in selecting parts is low.

An object of the present invention is to provide an electronic circuit mounting method that mounts an electronic circuit mounting an LSI that generates a large amount of heat and a large amount of wiring at a high mounting density and that is easy to maintain.

[Means for solving problems]

The above object is to attach a large wiring board integrally to a frame having a cooling capacity to form a mother board, and mount a semiconductor element between a heat conduction plate and a small wiring board to form a sub board. This is achieved by fixing the heat conduction plate of the sub board to the frame of the motherboard and electrically connecting the sub board and the motherboard with a connector.

[Action]

The present invention relates to a sub board in which a large wiring board is attached to a frame having a high cooling capacity by water cooling to serve as a mother board, and an LSI is mounted between a heat conduction plate also serving as a structure and a small wiring board attached to the heat conduction plate. By adopting the above configuration, the mother board and the sub-board can be divided into two parts, and the mother board and the sub board are electrically connected by pressure contact between the frame and the heat conductive plate and electrically connected by a connector. In addition, unlike the prior art, it does not require a large space occupied by a piston or the like, and has a feature that the board pitch can be increased when a plurality of motherboards are stacked and used. Further, the connection portion of the cooling water pipe which causes troubles such as water leakage is only the entrance / exit portion of the motherboard and not the sub-board, which facilitates maintenance. In addition, since the refrigerant is water, it can be easily used in general offices, there is no need for a large external device such as a compressor, and the refrigerant does not come into direct contact with parts.
There is no need for deterioration due to the refrigerant.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view showing an embodiment of an electronic circuit mounting method according to the present invention, and FIG. 2 is an exploded perspective view showing a structure of a sub board in the above embodiment. In FIG. 1, 1 is a large wiring board, 2 is a water cooling frame, 3 is a sub board, 4 is a connector, and 5 is a cooling water pipe. Further, in FIG. 2 for explaining the structure of the sub-board 3, 4 is a connector, 6 is a small wiring board, 7 is a heat conducting plate also serving as a structure, and 8 is an LS.
Reference numerals I and 9 denote heat conductors having elasticity with respect to stress, and 10 denotes a mounting portion to the water cooling frame 2. In the above configuration, the wiring of the LSI 8 is connected from the small wiring board 6 via the connector 4 to the large wiring board 1 connected by the heat conduction plate 7 and the water cooling frame 2. On the other hand, the heat generated from the LSI 8 is passed through the heat conductor 9, the heat conductive plate 7, and the water cooling frame 2 to the cooling water pipe 5 connected to the water cooling frame 2.
It is transmitted to the cooling water inside. The sub board 3 is the LSI 8
The small wiring board 6 mounted on each surface of the
It is possible to form it to a thickness of about 12 mm by using a heat dissipation grease or a heat conduction leaf spring as the heat conductor. Also, the sub board 3
Size of 10 cm x 10 cm, heat conductive plate 7 is 1.5 mm thick copper plate, heat conductive material is 50 μm thick, heat dissipation grease with contact size of 1 cm x 1 cm, 16 on each side, total 32 LS
When the I8 is mounted, the thermal resistance from the LSI 8 to the mounting portion of the water cooling frame 2 is about 5 ° C./W, and if the cooling water temperature is 35 ° C. and the LSI temperature is 70 ° C.,
It can consume up to 7W of power per chip.

The sub board 3 and the mother board in which the water cooling frame 2 and the large-sized wiring board 1 are integrated can be easily attached and detached by using a screw or the like, and the sub board 3 is adjusted to the size of the space between the water cooling frames. As a result, the total thickness of the board with the sub-board mounted can be about 15 mm, so it is possible to stack and use multiple boards as described above, and achieve a heat generation density of 1000 W /. You can

〔The invention's effect〕

As described above, in the electronic circuit mounting method according to the present invention, a large wiring board is integrally attached to a frame having a cooling capacity to form a mother board, and between the heat conductive plate and the small wiring board,
A semiconductor device is mounted and integrated into a sub board, and the heat conduction plate of the sub board is fixed to the frame of the motherboard, and by electrically connecting the sub board and the mother board with a connector,
By effectively utilizing the excellent heat transport capacity of the water-cooling method, and also by using the water-cooling frame and sub-board as a structure and also having a mechanical support function, it is possible to perform mounting with high density and high heat dissipation capacity. There are advantages. Furthermore, in this mounting method, the water channel is provided only on the mother board, and the structure in which the sub board is detachable makes it easy to perform maintenance such as partial testing and replacement, and it is possible to increase the reliability due to water leakage. And the LSI of this mounting method
Since is mounted by a general LSI surface mounting technique, it has an advantage that the degree of freedom in component selection is high.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of an electronic circuit mounting method according to the present invention, FIG. 2 is an exploded perspective view showing a structure of a sub board in the above embodiment, and FIG. 3 is a conventional electronic circuit mounting method. FIG. 4 is a configuration diagram showing another conventional example of an electronic circuit mounting method. 1 ... Large wiring board, 2 ... Frame 3 ... Sub board, 4 ... Connector 6 ... Small wiring board, 7 ... Heat conduction plate 8 ... Semiconductor element

Claims (1)

[Claims] 1. A large wiring board is integrally attached to a frame having a cooling capacity to form a mother board, and a semiconductor element mounted between a heat conductive plate and a small wiring board is integrated to form a sub board. An electronic circuit mounting method in which the heat conduction plate of the sub-board is fixed to the frame of the mother board, and the sub-board and the mother board are electrically connected by a connector.