JPS63292661A - Method of packaging electronic circuit - Google Patents

Abstract

PURPOSE:To package an electronic circuit, wherein LSIs characterized by large amounts of heating and wirings are provided at a high packaging density, and to facilitate maintenance, by fixing the heat conducting plate of a sub-board to the frame of a mother board, and electrically connecting the sub-board and the mother board with connectors. CONSTITUTION:In a sub-board 3, the wiring of an LSI 8 is connected to a large wiring substrate 1, which is connected with a heat conducting plate 7 and a water cooled frame 2 from a small wiring substrate 6 through a connector 4. Meanwhile, heat, which is yielded in the LSI 8, is conducted to cooling water in a cooling water pipe 5, which is connected to the water cooling pipe 2 through a heat conductor 9, a heat conducting plate 7 and the water cooling frame 2. The sub-board 3 and a mother board, wherein the water cooling frame 2 and the large wiring substrate 1 form a unitary body, can be readily attached and removed by using screwes and the like. Therefore, a plurality of the boards can be used in the laminated mode by making the size of the sub-board 3 to agree with the size of the space between the water cooling space. Thus, a high heat yielding density can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a large-scale electronic circuit mounting method having high packaging density and high heat generation density.

[Conventional technology]

Superhuman computers are a field that requires a large-scale electronic circuit mounting method with high packaging density and high heat generation density. The ultra-large computers have large-scale functions and are required to operate at high speeds, so they use LSIs with the highest performance, and water cooling or boiling cooling with high heat transport capacity is used.

A 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, 18 is a sub-board envelope, 19 is a water pipe, 20 is a cooling water, and 21 is a hose. . In the first conventional example of the above structure, the LSI chip 1
1 is absorbed by the heat transfer piston 15, which can freely expand and contract by a spring 16 to absorb thermal stress, and is further transferred to the cooling water 20 via the heat transfer cylinder 17, the sub-board envelope 18, and the water pipe 19. can be conveyed to.

On the other hand, electrical connections are made from the small wiring board 12 on which the chip is mounted to the large wiring board 1 via the terminals 14.

Next, a second conventional example will be explained with reference to FIG.

In the figure, 6 is a small wiring board, 8 is an LSI package, 22 is a sealed equipment rack, 23 is a refrigerant, and 24 is a compressor. As the refrigerant, a liquid having a boiling point close to the operating temperature of the LSI, such as Fluohanato, and having electrical insulation properties is used. In the second conventional example of the above structure, LS
When the I package 8 generates heat, the refrigerant 23 near the LSI package 8 evaporates, and the LSI is cooled by the heat of evaporation. The vaporized refrigerant 23 has its heat removed by the compressor 24 and returns to the vicinity of the LSI package 8 after being liquefied.

[Problem that the invention seeks to solve]

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 300W#
It remained at around 1. In addition, piping with a cooling water hose is required for each sub-board envelope, which increases the volume of the connection part of the piping, and there is a risk of disrupting the electrical circuit if water leaks due to poor connection. Furthermore, when the sub-board envelope is separated for maintenance, etc., it is necessary to attach and detach the hose, which poses problems such as the risk of water leakage.

In addition, in the second conventional example, as the total heat generation increases, the volume of the bubbles increases, and in particular, sufficient space is provided at the upper end of the small wiring board where the bubbles are concentrated, so that the liquid phase coolant comes into contact with the LSI package. There must be. Furthermore, since the volume of the refrigerant in the gas phase is five orders of magnitude larger than that in the liquid phase, a thick pipe line is required to lead the refrigerant after vaporization to the compressor.

Furthermore, there is a disadvantage that the compressor itself becomes large and the entire device becomes extremely large. Furthermore, since all parts come into contact with the refrigerant, if the materials are not carefully examined, there is a possibility of deterioration due to chemical reactions etc.
There is little freedom in selecting parts.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for mounting an electronic circuit, which includes an LSI that generates a large amount of heat and a large amount of wiring, with high packaging density and which is easy to maintain.

[Means for solving problems]

The above purpose is to create a motherboard by attaching a large wiring board integrally to a frame with cooling capacity, and a subboard to which a semiconductor element is mounted and integrated between a heat conduction plate and a small wiring board. This is achieved by fixing the heat conductive plate of the sub-board to the frame of the motherboard and electrically connecting the sub-board and the motherboard with a connector.

[For production]

In the present invention, a large wiring board is attached to a frame that has high cooling capacity through water cooling to form a motherboard, and an LSI is mounted between a heat conductive plate that also serves as a structure and a small wiring board attached to this to form a subboard. The motherboard and the subboard are thermally connected by pressure contact between the frame and the heat conduction plate, and electrically by a connector. This method does not require a large space occupied by pistons and the like as in the prior art, and has the feature that the board pitch can be increased when multiple motherboards are stacked. Furthermore, the connections for the cooling water piping, which can cause problems such as water leaks, are located only at the entrance/exit portion of the motherboard and not on the sub-board, which facilitates maintenance. Furthermore, since the refrigerant is water, it can be easily used in general businesses, and there is no need for large external equipment such as a compressor, and the refrigerant does not come into direct contact with parts.
There is no need to worry about deterioration due to 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 the electronic circuit mounting method according to the present invention, and FIG. 2 is an exploded perspective view showing the structure of a sub-board in the above embodiment. In Figure 1, 1 is a large wiring board, 2 is a water cooling frame, 3 is a sub board, and 4 is a large wiring board.
5 is a connector, and 5 is a cooling water pipe. Further, in FIG. 2 illustrating the structure of the sub-board 3, 4 is a connector, 6 is a small wiring board, 7 is a heat-conducting plate that also serves as a structure, 8 is an LSI, and 9 is a heat exchanger that has elasticity against stress. conductor, 10
is attached to the water-cooled frame 2 only partially.

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 coupled with the heat conductive plate 7 and the water cooling frame 2. On the other hand, L.S.
The heat generated from I8 is transmitted to the cooling water in the cooling water pipe 5 connected to the water cooling frame 2 via the heat conductor 9, the heat conduction plate 7, and the water cooling frame 2. The sub-board 3 has a small wiring board 6 with LSIs 8 mounted on both surfaces wrapped in a heat-conducting plate 7. The sub-board 3 has a structure in which a small wiring board 6 with LSIs 8 mounted on both surfaces is wrapped in a heat conductive plate 7. It is possible to form it to about 12n+n+. Also, the size of the above sub-board 3 is 10cmXl0■
, the heat conduction plate 7 is a copper plate with a thickness of 1.5 mm, the thickness is 50#Il+ as a heat conductor, the contact dimension is 1 cx+ X 1 an
When a total of 32 LSI8s (16 on each side, 16 on each side) are mounted using heat dissipation grease, the thermal resistance from the LSI8 to the mounting section of the water cooling frame 2 is approximately 5°C/W, and the cooling water temperature If the temperature is 35°C and the LSI temperature is 70°C, up to 7W of power can be consumed per chip.

The sub-board 3, the motherboard that integrates the water-cooling frame 2 and the large wiring board 1 can be easily attached and detached using screws, etc., and the sub-board 3 can be adjusted to fit the dimensions of the space between the water-cooling frames. As a result, the thickness of the entire board with the sub-board mounted can be reduced to about 15 mm, so it is possible to use multiple boards like the one above stacked on top of each other, and the heat generation density is 100 OW/
n can be realized.

〔Effect of the invention〕

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 cooling capacity to form a motherboard, and between a heat conductive plate and a small wiring board,
A sub-board is made by mounting and integrating semiconductor elements, and the heat conductive plate of the sub-board is fixed to the frame of the motherboard, and the sub-board and the motherboard are electrically connected by a connector to provide water cooling. By effectively utilizing the excellent heat transport ability of the system,
By using the water-cooling frame and sub-board as a structure, which also serves as a mechanical support function, there is an advantage that mounting can be performed with high density and high heat dissipation ability. Furthermore, with this mounting method, water channels are provided only on the motherboard, and the sub-board is made removable, making maintenance such as partial testing and replacement easier, and has the advantage of increasing reliability against problems such as water leaks. In addition, since the LSI of this mounting method is mounted using common LSI surface mounting technology, there is an advantage that there is a high degree of freedom in component selection.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view showing an embodiment of the electronic circuit mounting method according to the present invention, Fig. 2 is an exploded perspective view showing the structure of the sub-board in the above embodiment, and Fig. 3 is an exploded perspective view showing an example of the electronic circuit mounting method according to the present invention. FIG. 4 is a block 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...Thermal conduction plate 8...Semiconductor device 12 2 Kenei/3 烁sai 4 Die ■------]8゜

Claims (1)

[Claims] 1. A large wiring board is integrally attached to a frame with cooling capacity to form a motherboard, and a semiconductor element is mounted and integrated between a heat conductive plate and a small wiring board to form a subboard. An electronic circuit mounting method comprising: fixing a heat conductive plate to a frame of the motherboard, and electrically connecting the sub-board and the motherboard with a connector.