JPH0521663A - Cooling structure of integrated circuit - Google Patents

Abstract

PURPOSE:To enhance the cooling capacity of the water cooling structure of an equipment such as a computer where an integrated circuit large in heat release value is mounted by a method wherein a heat transfer path between the integrated circuit and cooling water is lessened in heat resistance. CONSTITUTION:Thermal conduction pistons 5 are prepared for each of integrated circuits 4, whereby the contact surface of the integrated circuit 4 with the thermal conduction pistons 5 can be increased in area, so that thermal resistance between the integrated circuit 4 and the thermal conduction pistons 5 can be lessened. Even if the integrated circuit 4 is mounted as tilted, the thermal conduction pistons 5 move independently, so that the circuit 4 can be cooled down without any trouble. A heat transfer path between the integrated circuit 4 and cooling water can be lessened in thermal resistance, so that a cooling structure of this design can be enhanced in cooling capacity. Therefore, the highly integrated circuit 4 larger in heat release value can be mounted on an electronic equipment such as a computer, so that the equipment can be enhanced in capacity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an integrated circuit cooling structure, and more particularly, efficiently cools heat generated from an integrated circuit of an electronic device in which an integrated circuit having a large heat generation amount is mounted such as a large computer. Regarding cooling structure.

[0002]

2. Description of the Related Art Conventionally, as a means for cooling an integrated circuit mounted on a circuit board, an air cooling system by forced convection has been widely adopted. However, in recent years, in large computers and the like, the air-cooling method has become insufficient to cope with the increase in the amount of heat generated by the improvement in the degree of integration of elements. Therefore, the liquid cooling system has been adopted.

FIG. 3 shows a conventional example of a liquid cooling module.
A ceramic circuit board 1 on which an integrated circuit 4 is soldered with solder balls 7 is covered with a liquid cooling structure composed of a heat conduction block 2, a heat conduction piston 5, a spring 6, and a low temperature plate 3 to integrate the heat conduction piston 5. It is cooled by being pressed against the circuit 4. The problem with this method is that the contact point between the heat-conducting piston and the integrated circuit becomes one point and the thermal resistance increases. The reason for this is that, due to the manufacturing technology, the integrated circuit is slightly tilted on the circuit board to absorb the error that is soldered, so the contact surface of the heat conducting piston with the integrated circuit must be rounded,
Therefore, there is only one contact point with the integrated circuit.

As another method of absorbing soldering error,
There is a method in which a minute gap is provided without bringing the heat conducting piston and the integrated circuit into contact with each other, and the gap is filled with a high heat conductive filler. However, this method has the drawbacks that there is concern about the aging change of the filler and that the thermal resistance becomes larger than that of direct contact.

As a method for making the contact surface between the integrated circuit and the cooling body flat, the method of FIG. 4 (Japanese Patent Laid-Open No. 62-13).
9346). In this method, instead of the heat-conducting piston, a micro fin 9 made of ceramic, whose upper part is notched like a comb tooth, is placed on the integrated circuit 4, and the bottom surface of the ceramic that contacts the low temperature plate 3 and seals the module. It is cooled by meshing the same notches 8 with each other. Since the meshing portion has a minute gap, it is possible to absorb the soldering error of the integrated circuit. However, there are manufacturing technical problems such as it is difficult to make a tooth-shaped cut in a ceramic, and it takes time to manufacture.

[0006]

An error in soldering an integrated circuit is an obstacle to lowering thermal resistance. It is important to develop a method of absorbing the error and bringing the cooling body and the integrated circuit into contact with each other as closely as possible. Has become a problem. Another problem is to reduce the manufacturing cost without adopting a complicated structure.

[0007]

SUMMARY OF THE INVENTION The present invention resides in the provision of multiple heat transfer pistons per integrated circuit.

[0008]

With the above means, it is possible to absorb the soldering error and reduce the thermal resistance by increasing the contact portion between the integrated circuit and the heat conducting piston to improve the cooling efficiency. Further, if the heat conducting piston has a cylindrical shape, a cylindrical hole may be formed in the heat conducting block, and since the structure is not so complicated, it is possible to suppress an increase in manufacturing cost.

[0009]

Embodiments of the present invention will be described below with reference to FIGS.
Will be explained.

FIG. 2 shows a cut model of a liquid cooling module, in which a ceramic circuit board 1 on which an integrated circuit 4 is soldered, a heat-conducting block 2, a heat-conducting piston 5, and a low-temperature plate 3 are used for liquid cooling. Cover the structure,
It is shown that three heat conduction pistons 5 are pressed against one integrated circuit 4. The heat generated in the integrated circuit is transmitted in the order of the heat conduction piston, the heat conduction block, and the low temperature plate, and is carried away by the cooling water flowing in the low temperature plate to the outside of the liquid cooling module.

FIG. 1 is a sectional view of the liquid cooling module, which is an enlarged view of a portion related to cooling of the integrated circuit in FIG. The integrated circuit 4 is soldered to the ceramic circuit board 1 with solder balls 7. The heat conducting piston 5 is pressed against the integrated circuit 4 by the spring 6.

Here, the thermal resistance is the sum of four thermal resistances from the integrated circuit to the heat conducting piston, the heat conducting piston to the heat conducting block, the heat conducting block to the low temperature plate, and the low temperature plate to the cooling water. It becomes a thing.

If the number of heat conducting pistons is increased as in this embodiment, the contact area between the integrated circuit and the heat conducting piston is increased as compared with the case of one piston. It is possible to reduce the heat resistance of (1 / the number of heat conduction pistons). Also, in order to increase the number of heat transfer pistons, the pistons must be made thin, but the decrease in the area of the boundary surface with the heat transfer block that occurs due to this can be absorbed by making the heat transfer pistons longer, An increase in the thermal resistance between the heat conducting piston and the heat conducting block can be eliminated. Furthermore, since there is no change in the thermal resistance from the heat conduction block to the cold plate and from the cold plate to the cooling water, the thermal resistance from the integrated circuit to the cooling water can be reduced eventually.

Even when the integrated circuit is mounted in an inclined manner, the heat conducting pistons move independently as shown in FIG. 5, so that the contact surface between the heat conducting piston and the integrated circuit is lifted or the integrated circuit is strongly pressed. It does not get stuck and can be cooled without problems.

[0015]

As described above, according to the present invention,
The thermal resistance from the integrated circuit to the cooling water can be reduced,
Cooling capacity is improved. Therefore, it is possible to use a highly-integrated integrated circuit that generates a larger amount of heat, and it is possible to improve the capabilities of electronic devices such as computers.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a liquid cooling module according to an embodiment of the present invention.

FIG. 2 is a diagram showing a cut model of a liquid cooling module according to an embodiment of the present invention.

FIG. 3 is a diagram showing a conventional example of a liquid cooling module.

FIG. 4 is a diagram showing an example of a liquid cooling module using micro fins.

FIG. 5 is a diagram showing an example in which an integrated circuit is tilted and mounted in an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ceramic circuit board, 2 ... Heat conduction block, 3 ... Low temperature plate, 4 ... Integrated circuit, 5 ... Heat conduction piston, 6 ... Spring, 7 ... Solder ball.

Claims (1)

Claim: What is claimed is: 1. A cooling body, in which a refrigerant flows heat generated from an integrated circuit mounted and mounted on a circuit board such as a printed wiring board or a ceramic wiring board. In an integrated circuit cooling structure for cooling by contacting a circuit, a plurality of contact portions between the cooling body and the integrated circuit are provided for each integrated circuit. Cooling structure.