JP2504059B2 - Electronic circuit package cooling structure - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for an electronic circuit package used in electronic equipment such as a large-sized information processing device.

(Prior Art) Conventionally, as a cooling structure of this type, a method of accommodating a plurality of wiring boards on which integrated circuit elements are mounted in a rack and cooling by using forced convection of air by a cooling fan is widely used. . Further, in recent years, especially as integrated circuits have become large-scale and highly integrated, in order to maximize the device performance and realize a high-performance device, the device mounting method in the rack has been significantly increased in density. Therefore, a liquid refrigerant such as water having a larger heat capacity than air is circulated in the vicinity of the integrated circuit element, and a metal part is brought into contact with the case of the integrated circuit element, and the heat is transferred to the refrigerant by the heat conduction to exhaust the heat. Is also being used.

An example of this structure is shown in FIG. 3. This structure is one in which a plurality of LSIs 14 each having a heat spreader 15 on the upper surface are mounted on a printed circuit board 13 and the heat spreader 15 is pressed from above to be cooled. In addition, the cold plate 16 is provided with a plurality of water channels 17, and the coolant is flowed through the water channels 17 to keep the temperature of the LSI 14 low. Here, the heights of the LSIs 12 are not necessarily aligned on one plane due to dimensional accuracy of components, variation in mounting, warpage, undulations, etc. of the printed circuit board. Therefore, the thermal paste 1 is applied to the surface of the cold plate 16 pressed against the LSI 14.
8 is sealed with film 19, and its softness is used to absorb the height variation. The cold plates 16 are provided on both sides of the circuit package, and the film 19 and the thermal paste 18 are deformed by being mechanically fixed and pressed, and contact the heat spreader 15 to radiate heat. The heat generated by LSI14 is film 19
Further, the heat is radiated from the cold plate 16 to the water flowing in the water channel 17 via the thermal paste 18.

(Problems to be Solved by the Invention) Of the above-described conventional cooling structures, the first type of forced air cooling system has been increased in air volume in order to cope with the recent increase in heat generation density of electronic devices. However, the noise from the cooling fan has become a problem with it, and it is considered that the cooling capacity has reached its limit. In addition, in the second conduction cooling method, if the height of the LSI exceeds a certain limit and the material such as the thermal paste described in the example of FIG. Since the air with poor heat transfer characteristics is present in the system where heat is transmitted between the two, the cooling capacity decreases and the reliability of the LSI is adversely affected.
For this reason, there is a drawback in that it is difficult to apply to a device such as a storage device of a computer, which is supplied as a standard product in a case and is configured by using a large number of integrated circuit elements which are not only one kind in size. .

(Means for Solving Problems) A cooling structure of the present invention includes a rack for accommodating a plurality of wiring boards on which a plurality of integrated circuit elements are mounted, a cooling plate having tubes at both ends, and a plurality of the cooling plates. A heat exchanger comprising at least two headers, one at the inlet side and one at the outlet side, which are joined to each other so as to form a flow path for distributing the secondary refrigerant, to the tubes at both ends, , The wiring board and the cooling plate are fixed in the casing so as to be arranged alternately at a constant interval, the casing is filled with an insulating, inactive primary refrigerant, the heat generated in the integrated circuit element through the primary refrigerant Is transmitted to the cooling plate, and further, is transmitted through the inside of the cooling plate by conduction to be discharged to the secondary refrigerant.

(Example) Next, the present invention will be described with reference to the drawings with reference to examples.

FIG. 1 is a side view showing a partially cut structure of a cooling structure according to an embodiment of the present invention. In this figure, 1 is an integrated circuit element, 2 is a wiring board on which a plurality of integrated circuit elements 1 are mounted, 3 is a rack for accommodating a plurality of wiring boards 2, and 4 is a wiring board 2 positioned and fixed on the rack 3. It is a card guide for. Reference numeral 5 denotes a cooling plate, both ends of which are tubes, through which the secondary refrigerant 6 flows. Reference numeral 7 denotes a header for distributing the secondary refrigerant 6 to the pipes at both ends of the cooling plate 5, and here, as shown in FIG. 2, there are a total of four headers above and below the cooling plate 5 on the inlet side and the outlet side, The tubes at both ends of the cooling plate 5 are joined by brazing to form a secondary refrigerant flow path. The secondary refrigerant is distributed from the inlet side header to the cooling pipe, and is collected and discharged at the outlet side header. 8 is a rack 3 that houses the wiring board 2.
And a heat exchanger 9 in which the cooling plate 5 is attached to the header 7, and the casing has a sealed structure. Reference numeral 10 denotes a pipe-shaped joint for fixing the heat exchanger 9 to the casing 8 and connecting the secondary refrigerant flow path to the outside, and is attached to the casing 8 so as to maintain the sealing structure of the casing 8. . The frame 3 is fixed to the casing by a frame 11 attached inside the casing 8. . The casing 8 is filled with an insulating, inactive primary refrigerant 12. As the primary refrigerant 12, for example, 3M
"Fluorinert" of the company is suitable.

Next, a heat transfer path in the cooling structure of the present invention will be described. Part of the heat generated in the integrated circuit element 1 is transferred to the wiring board 2, and the rest is directly transferred to the primary refrigerant 12, and is transferred to the cooling plate 5 by conduction and convection. Further, the heat is conducted inside the cooling plate 5 to the pipes at both ends of the heat conducting plate, and is then discharged to the secondary refrigerant 6 from there.

In this way, without directly contacting the cooling plate with the integrated circuit element,
By adopting a structure that transfers heat via the primary refrigerant, thermal stress due to temperature rise does not adversely affect the connection part between the integrated circuit element and the wiring board, and the cooling performance due to variations in mounting height and inclination of the integrated circuit element Since it is not affected, noise is generated by a device composed of many integrated circuit elements that are supplied in a case as a standard product such as a memory device of a computer, which was conventionally mostly forced air cooling, and have several sizes. It can be cooled without doing so.

(Effects of the Invention) As described above, the present invention has a structure in which heat is transferred via the primary refrigerant without directly contacting the cooling plate with the integrated circuit element, so that thermal stress due to temperature rise and the integrated circuit element and wiring In addition to having no adverse effect on the connection portion with the substrate, it is also possible to cope with variations in mounting height and inclination of integrated circuit elements. Further, by dividing the refrigerant into a primary refrigerant that directly immerses the integrated circuit element and a secondary refrigerant that does not contact the integrated circuit element, a method of transmitting heat to the refrigerant by conduction and cooling is used together in one device. Even in this case, the cooling device that circulates and supplies the refrigerant is only required for one kind of refrigerant,
There is an effect that the structure can be simplified and the cost can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cutaway side view of a cooling structure according to an embodiment of the present invention, FIG. 2 is an external view of a heat exchanger assembly according to an embodiment of the present invention, and FIG. The figure is a sectional view showing an example of a conventional cooling structure. 1 ... Integrated circuit element, 2 ... Wiring board, 3 ... Rack, 4 ...
… Card guide, 5… Cooling plate, 6… Secondary refrigerant, 7…
… Header, 8 …… Casing, 9 …… Heat exchanger, 10 ……
Joint, 11 …… frame, 12 …… primary refrigerant.

Claims (1)

(57) [Claims] 1. A rack for accommodating a plurality of wiring boards on which a plurality of integrated circuit devices are mounted, a cooling plate having tubes at both ends, and a flow path for distributing a secondary refrigerant to the plurality of cooling plates and the tubes at both ends. At least two inlet and outlet sides joined to form a
A heat exchanger comprising a header of a book, the rack and the heat exchanger are fixed in a casing so that the wiring board and the cooling plate are alternately arranged at a constant interval, and in the casing. Insulating and inactive primary refrigerant is filled, the heat generated in the integrated circuit element is transferred to the cooling plate via the primary refrigerant, and further transferred by conduction in the cooling plate to be exhausted to the secondary refrigerant. A cooling structure for an electronic circuit package characterized by the above.