JP2751740B2 - Integrated circuit cooling structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for an integrated circuit used in electronic equipment or the like using liquid cooling, and more particularly to an immersion for cooling by jetting a refrigerant directly from a nozzle using an insulating refrigerant. The present invention relates to a jet cooling structure.

[0002]

2. Description of the Related Art Generally, immersion jet cooling is used for integrated circuit chips,
Alternatively, the heat sink is mounted on the heat dissipation surface of the integrated circuit chip, and the heat sink is immersed in an insulating liquid, and the coolant is ejected from the nozzle onto the integrated circuit chip or the heat sink. FIG. 5 shows an example of such a conventional immersion jet cooling refrigerant supply structure. As described above, the conventional coolant supply structure for immersion jet cooling has a structure in which the coolant entering from the container inlet is supplied to all the integrated circuit chips on the substrate at one time. The coolant that has entered the container is blown out from each nozzle at a time through all the integrated circuit chips 1 on the substrate through the flow path inlet 7. After that, the refrigerant flows out of the container by the same amount as that ejected from the nozzle.

[0003]

In the above-described conventional cooling structure for an integrated circuit, the flow rate at the inlet of the container increases in proportion to the power consumption of the integrated circuit chip existing on the substrate. For this reason, when the heat generation density of the integrated circuit chip increases, a problem arises in that the refrigerant supply device and the piping become large, and a large amount of the refrigerant itself is required.

[0004] Further, since the integrated circuit chip 1 and the heat sink on the substrate are all immersed in the refrigerant, the assembly and disassembly operations when replacing the substrate and the integrated circuit chip are complicated.

[0005]

The cooling structure according to the present invention comprises:
In a cooling structure of an integrated circuit that uses a low-boiling insulating refrigerant to directly blow out the refrigerant from a nozzle and cause the refrigerant to collide, a small-diameter hole is formed in a fin side wall of the integrated circuit chip, and A flat plate made of a material having good thermal conductivity is attached to which a cylindrical fin having an upper lid with a hole through which the hole passes is provided. A cold plate made of a material having good conductivity is provided, and a cylindrical cold plate wall is provided at a position corresponding to the flat plate so as to surround the cylindrical fin, and a wall between the cylindrical cold plate wall and the flat plate is provided. Has a structure characterized in that it is fixed via a thin plate spring, and the insulating refrigerant passes through a flow path inlet provided in the cold plate, and the tip thereof is inside the cylindrical fin. After being ejected from a nozzle having a length enough to reach and vertically provided to each integrated circuit, the cold plate was opened through a small-diameter hole in the side wall of the cylindrical fin. It is characterized by flowing out of the flow path outlet and heading to the flow path entrance for the next integrated circuit chip.

[0006]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of a cooling structure for an integrated circuit according to the present invention.

In FIG. 1, reference numeral 1 denotes an integrated circuit chip, the chip heat radiating surface of which is a flat plate 3 made of a material having good heat conductivity and having a cylindrical fin 4 having a small-diameter hole 5 formed in a fin side wall;
They are connected by solder or a thermally conductive adhesive 2. The flow path inlet 7 is provided above the fins so that the insulating refrigerant flows.
And a cold plate 12 made of a material having good thermal conductivity and provided with a flow path outlet 8.

The channel inlet 7 has such a length that the end reaches the inside of the cylindrical fin 4 through a hole formed in the upper lid of the cylindrical fin 4, and is vertically opposed to the integrated circuit chip 1. It is connected to the nozzle 6 provided. Further, a cylindrical wall 11 is provided on the cold plate 12 for the integrated circuit chip 1, and the flat plate 3 and the cylindrical wall 11 of the cold plate 12 are connected via a thin plate spring 9. A cooling bath 10 is formed in the inner space formed by the two, and the flow passage outlet 8 is connected to a flow passage inlet of the next cooling bath via a flow passage provided in the cold plate 12.

FIG. 2 shows a detailed example of the shape of the thin plate spring 9 and the flat plate 3 on which the cylindrical fin 4 is mounted. Thin leaf spring 9
Is a thin disk ring, the cross section of the ring is formed to have a convex part (or concave part) on the way from the inside to the outside of the ring, and the inside of the ring is connected with the flat plate 3 on which the cylindrical fin 4 is mounted. Cold plate 1 outside the ring
It is connected to two cylindrical walls 11.

FIG. 3 is a sectional view of the cooling structure showing the state of circulation of the refrigerant when the cooling structure of the integrated circuit shown in FIG. 1 is used. An insulating refrigerant such as fluorine carbide travels in the direction of the arrow in the figure. The refrigerant ejected from the nozzle 6 to the refrigerant layer through the passage inlet 7 collides with the flat plate 3 and flows out of the fins through the small-diameter holes 5 formed in the side walls of the cylindrical fins 4. The outflowing refrigerant then flows to the next cooling tank through the flow path outlet 8.

Since the thin plate spring 9 is a flexible spring having a convex portion (or concave portion) formed in the center of the ring, it can absorb variations in height and inclination of each integrated circuit chip 1 when mounted on a substrate, and can be reliably mounted. The flat plate 3 on the entire heat dissipation surface of the integrated circuit chip 1
Can be attached. Further, stress relaxation due to thermal expansion caused by heat generation of the integrated circuit chip 1 is also performed.

Further, in the present structure, the flat plate 3 and the cylindrical wall 11 of the cold plate 12 are connected via the thin plate spring 9, and one of them is immersed in an insulating refrigerant by press-contacting one of them. (Cooling tank portion) and the integrated circuit chip can be easily separated. For this reason, assembly or disassembly work when mounting the integrated circuit chip can be simplified, and replacement of the substrate or the integrated circuit chip can be easily performed.

By the way, in immersion cooling using a low-boiling-point insulating refrigerant, cooling is performed by causing the refrigerant to boil by the heat generated by the chips of the integrated circuit. For this reason, in order to efficiently remove heat of vaporization from the fins, it is important how quickly bubbles generated by boiling are removed.

In the present cooling structure, the nozzle 6 enters the inside of the cylindrical fin 4 through a hole 13 formed in the upper lid of the cylindrical fin 4. Since the cylindrical fin 4 is provided with an upper lid, the refrigerant ejected from the nozzle 6 collides with the flat plate 3, and the rebound does not flow out of the cylindrical fin 4. It flows out of the fin through the small hole 5 formed in the side wall. The small-diameter holes 5 increase the heat transfer area and provide a stable point of generation of bubbles generated by boiling. For this reason, the refrigerant can contact all the heat transfer surfaces of the fins, and can eliminate bubbles generated on the heat transfer surface in a very small amount.

Further, in the present cooling structure, since the cooling tank 10 is surrounded by the cylindrical wall 11 of the cold plate 12, the air bubbles are easily cooled, and the air bubbles of the refrigerant can be quickly liquefied. Therefore, the heat exchange can be performed efficiently, so that the cooling efficiency is improved, and at the same time, the pressure increase in the container due to the generation of bubbles can be suppressed.

FIG. 4 shows a bellows 1 instead of the thin plate spring 9 and the cylindrical wall 11 of the cold plate 12 shown in FIG.
4 is another embodiment of the present invention using No. 4. Providing the bellows 14 between the flat plate 3 and the cold plate 12 has the same effect as when the thin plate spring 9 is used.

[0018]

As described above, in the cooling structure of the present invention, the size of the refrigerant supply device and the piping can be prevented from being increased, the required amount of the refrigerant can be reduced, and the thermal stress can be reduced. And the disassembly and assembly of the cooling device can be improved.

Further, since the bubbles generated by the boiling are quickly liquefied, the cooling efficiency is good and the pressure in the cooling device is prevented from increasing.

[Brief description of the drawings]

FIG. 1 is a sectional view of one embodiment of the present invention.

FIG. 2 is a detailed view of a thin plate spring and a cylindrical fin in FIG. 1;

FIG. 3 is a cross-sectional view showing a state of circulation of a refrigerant when the immersion jet cooling structure shown in FIG. 1 is used.

FIG. 4 is a sectional view of another embodiment of the present invention.

FIG. 5 is a sectional view showing a state of circulation of a refrigerant in a conventional immersion jet cooling structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Integrated circuit chip 2 Solder or thermoelectric adhesive 3 Flat plate made of a material with good thermoelectric property 4 Cylindrical fin 5 Small diameter hole 6 Nozzle 7 Flow path inlet 8 Flow path exit 9 Thin plate spring 10 Cooling tank 11 Wall 12 Cold Plate 13 holes 14 Bellows

Claims (2)

(57) [Claims] 1. A cooling structure for an integrated circuit that uses an insulating refrigerant having a low boiling point to directly blow out a refrigerant from a nozzle and cause the refrigerant to collide with the refrigerant. A flat plate made of a material having good thermal conductivity, which is provided with a cylindrical fin having an upper lid with a hole for allowing the nozzle to pass therethrough, is connected thereto, and a flow of an insulating refrigerant flows above the fin. A cold plate made of a material having good thermal conductivity is provided, and a wall of a cylindrical cold plate is provided at a position corresponding to the flat plate so as to surround the cylindrical fin. The flat plate has a structure characterized by being fixed via a thin plate spring, and the insulating refrigerant passes through a flow path inlet provided in the cold plate, and has a cylindrical end. After being ejected from a nozzle which is long enough to reach the inside of the fin and is provided to be vertically opposed to each integrated circuit, the cold plate passes through a small-diameter hole in the side wall of the cylindrical fin. A cooling structure for an integrated circuit, wherein the cooling structure flows out from a flow path outlet opened to a flow path entrance for a next integrated circuit chip. 2. The cooling structure for an integrated circuit according to claim 1, wherein a bellows is used in place of said thin plate spring and said cold plate wall made of a material having good heat conductivity.