JPH07142651A - Structure for cooling integrated circuit - Google Patents

Abstract

PURPOSE:To prevent the transition of boiling on the surface of an integrated circuit to the film boiling in the immersion/jet cooling of the integrated circuit, and also to improve cooling efficiency. CONSTITUTION:By having the fins 4 of a heat sink formed in a cylindrical shape, the refrigerant jetted out from the secondary nozzle 6, which is connected by the primary nozzle 9 and a flexible hose 8, can be brought into contact with an excellent heat conductive flat plate 3 and the whole heat conductive surface through the intermediary of an integrated circuit chip 1 and solder or a heat conductive bonding agent 2. Also, as the refrigerant can be forcedly discharged from a plurality of small holes 5 on the side face of the fins 4 by providing an upper cover 7 on the cylindrical fins 4, the boiling bubblers generated in the small holes 5 can be removed when they are very small.

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 an electric device or the like using liquid cooling, and in some cases, an insulating refrigerant is used for cooling by directly ejecting the refrigerant from a nozzle. It relates to the structure of jet cooling.

[0002]

2. Description of the Related Art In the conventional immersion jet cooling, a refrigerant is directly jetted from a nozzle onto an integrated circuit chip immersed in an insulating liquid or a heat sink bonded to a heat dissipation surface of the integrated circuit chip.

FIG. 5 shows the shape of a heat sink 21 used in a conventional integrated circuit cooling structure. In the conventional heat sink 21, the fins 10 having a constant pitch are integrated circuit chips 1
Solder or heat conductive adhesive 2 so that it is perpendicular to the surface of the
Attached to the integrated circuit 1. Further, the surface of the fin 10 of the heat sink 21 is finished to be smooth or slightly rough, and an outline of the conventional cooling structure is shown in FIG. The upper end of the heat sink 21, which is the nozzle side, is open. The coolant jetted from the primary nozzle 9 vertically collides with the central portion of the surface of the integrated circuit chip 1 of the heat sink 21, and thereafter returns and flows out from the upper end portion of the heat sink 21.

[0004]

In this conventional integrated circuit cooling structure, the refrigerant jetted from the nozzle flows along the flow of the arrow shown in FIG. 6, and the central portion of the integrated circuit chip has a fin surface. Bubbles generated by boiling can be removed. Therefore, in the central portion of the integrated circuit chip, the cooling efficiency can be improved, but in the peripheral portion of the chip, the fins in the central portion of the heat sink become an obstacle, so that the flow of the refrigerant is blocked and the cooling efficiency can be increased much. Can not. Therefore, there arises a problem that the surface temperature of the integrated circuit chip is different between the central part and the peripheral part of the chip and the cooling effect is small.

[0005]

SUMMARY OF THE INVENTION A cooling structure for an integrated circuit according to the present invention is a cylindrical fin in which a flat plate having good thermal conductivity is fixed on an integrated circuit chip and a plurality of small holes are formed on the flat plate. Is formed, and a lid having a nozzle penetrating therethrough is attached to the upper part of the cylindrical fin.

In the integrated circuit cooling structure of the present invention, a spiral groove can be formed inside the nozzle provided on the upper lid of the cylindrical heat sink.

The cooling structure for an integrated circuit according to the present invention may have a certain angle with respect to the flat plate having the tip of the nozzle provided on the upper lid of the cylindrical heat sink fixed to the integrated circuit chip.

In the cooling structure for an integrated circuit according to the present invention, the nozzle provided on the lid may be connected to the nozzle for ejecting the refrigerant through the flexible hose.

[0009]

The present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view of an embodiment of the present invention.

The heat sink 22 in this embodiment is a flat plate 3,
It is composed of a cylindrical fin 4, an upper lid 7 and a secondary nozzle 6. A face-down integrated circuit chip 1 has a flat plate 3 having good heat conductivity bonded to a chip heat radiation surface via solder or a heat conductive adhesive 2. Further, the flat plate 3 is provided with a cylindrical fin 4, and a plurality of small-diameter holes 5 penetrating through the front and back are formed on the side surface of the fin 4. Further, an upper lid 7 having a secondary nozzle 6 penetrating therethrough is adhered to the upper end of the fin 4. The secondary nozzle 6 provided on the upper lid 7 is connected to the primary nozzle 9 via a flexible hose 8.

FIG. 2 is a sectional view of this embodiment. Insulative refrigerant such as fluorocarbon proceeds in the direction of the arrow in the figure.
The refrigerant that has passed through the primary nozzle 9 passes through the flexible hose 8 made of a rubber tube or the like having excellent elasticity from the secondary nozzle 6 attached to the upper lid 7 of the heat sink 22 to the heat sink 22.
It collides with the flat plate 3 having good thermal conductivity inside the cylindrical fin. The refrigerant colliding with the flat plate 3 removes heat from the integrated circuit chip 1 and flows out of the heat sink 22 through the small-diameter hole 5 formed in the side surface of the cylindrical fin 4.

The heat sink 22 of this embodiment has a cylindrical fin shape so that the refrigerant can be brought into contact with all the heat transfer surfaces of the fin 4.

Further, in boiling cooling, it is important that the refrigerant in contact with the fins efficiently removes the heat of vaporization of boiling from the fins. However, when the fin temperature rises above a certain temperature, the boiling mode changes from nucleate boiling to film boiling. In the film boiling region, since a vapor film exists between the fins and the refrigerant, the heat of vaporization taken by the refrigerant from the fins is greatly reduced. Therefore, in order to prevent the boiling from transitioning to the film boiling, it is necessary to quickly remove the minute bubbles generated in the initial boiling stage from the fin heat transfer surface. It is important to provide a large number of stable bubble generation points.

In the heat sink 22 of this embodiment, a plurality of small-diameter holes 5 are formed on the surface of the fin 4 so that a stable generation point of a large number of bubbles can be provided therein.

Further, by providing the upper lid 7 on the upper portion of the fin 4, after the refrigerant collides with the flat plate 3, the refrigerant is forcibly discharged from the upper portion of the fin through the hole 5 formed on the side surface of the fin 4. Can be drained. Therefore, the bubbles generated in the small-diameter holes 5 can be swept away, the growth of the bubbles can be suppressed, and the transition to film boiling can be prevented. Further, the heat transfer area of the entire heat sink can be increased by allowing the refrigerant to pass through the small-diameter hole through the forced circle.

Further, the secondary nozzle 6 attached to the upper lid 7 of the heat sink of this embodiment is connected to the primary nozzle 9 through the flexible hose 8, so that the arrangement and size of the integrated circuit chips are irrelevant. Instead, the secondary nozzle can be installed in the center of the integrated circuit chip 1. Further, this allows the cooling device to have a certain degree of freedom in its collection, so that the problem of mounting error of the integrated circuit chip can be solved and the assembling work can be simplified. Further, the flexible hose 8 also has a role of relieving stress generated by thermal expansion of the integrated circuit chip 1 due to heat generation.

FIG. 3 is a perspective view of another embodiment of the present invention, which has a structure in which a spiral groove is cut inside the secondary nozzle 11 of the heat sink 23. The refrigerant having passed through the primary nozzle 9 is given a swirling motion when passing through the inside of the secondary nozzle 11, and collides with the heat dissipation surface of the integrated circuit while spirally swirling. Therefore, a swirling motion is added to the fins 4 of the heat sink due to the collision of the refrigerant inside, so that the efficiency of heat transport can be improved.

FIG. 4 is a sectional view of still another embodiment of the present invention. In the embodiment of FIG. 4, the secondary nozzle of the heat sink 24 is composed of the curved tube secondary nozzle 14. The refrigerant having passed through the primary nozzle 9 is ejected from the curved pipe secondary nozzle 14 and then collides with the heat dissipation surface of the integrated circuit while swirling along the inner surface of the cylindrical fin. Therefore, the effect of heat transport of the refrigerant can be enhanced as in the embodiment shown in FIG.

[0020]

As described above, in the cooling structure for an integrated circuit according to the present invention, the flow of the coolant due to the jet flow is not obstructed by the fins of the heat sink, and the fine bubbles generated in the initial boiling stage are swept away. It is effective in improving the cooling efficiency of the integrated circuit, simplifying the assembly of the cooling device, and relaxing the thermal stress.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

2 is a cross-sectional view of the embodiment shown in FIG.

FIG. 3 is a perspective view of another embodiment of the present invention.

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

FIG. 5 is a perspective view of a heat sink used in a conventional integrated circuit cooling structure.

6 is a cross-sectional view of a conventional integrated circuit cooling structure using the heat sink shown in FIG.

[Explanation of symbols]

 1 Integrated Circuit Chip 2 Solder or Thermal Conductive Adhesive 3 Flat Plate with Good Thermal Conductivity 4 Cylindrical Fin 5 Small Diameter Hole 6 Secondary Nozzle 7 Upper Nozzle 8 Flexible Hose 9 Primary Nozzle 10 Fin 11 Spiral Cut Secondary Nozzle 12 Bending Tube secondary nozzle 21, 22, 23, 24 Heat sink

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[Procedure amendment]

[Submission date] May 10, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be amended] Detailed explanation of the invention

[Correction method] Change

[Correction content]

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for an integrated circuit used in an electric device or the like using liquid cooling, and in particular, a dipping method in which an insulating refrigerant is used to directly cool a nozzle to cool it It relates to the structure of jet cooling.

2. Description of the Related Art In the conventional immersion jet cooling, a refrigerant is directly jetted from a nozzle onto an integrated circuit chip immersed in an insulating liquid or a heat sink bonded to a heat dissipation surface of the integrated circuit chip. FIG. 5 shows the shape of a heat sink 21 used in a conventional integrated circuit cooling structure. The conventional heat sink 21 is attached to the integrated circuit 1 by the solder or the heat conductive adhesive 2 so that the fins 10 having a constant pitch are perpendicular to the surface of the integrated circuit chip 1. Further, the surface of the fin 10 of the heat sink 21 is finished to be a smooth surface or a slightly rough surface, and the outline of the conventional cooling structure is shown in FIG.
Shown in. The upper end of the heat sink 21, which is the nozzle side, is open. The coolant jetted from the primary nozzle 9 vertically collides with the central portion of the surface of the integrated circuit chip 1 of the heat sink 21, and thereafter returns and flows out from the upper end portion of the heat sink 21.

In this conventional integrated circuit cooling structure, the refrigerant jetted from the nozzle flows along the flow of the arrow shown in FIG. 6, and the central portion of the integrated circuit chip has a fin surface. Bubbles generated by boiling can be removed. Therefore, in the central portion of the integrated circuit chip, the cooling efficiency can be improved, but in the peripheral portion of the chip, the fins in the central portion of the heat sink become an obstacle, so that the flow of the refrigerant is blocked and the cooling efficiency can be increased much. Can not. Therefore, the surface temperature of the integrated circuit chip differs between the central part and the peripheral part of the chip, which causes a problem that the cooling effect is small.

SUMMARY OF THE INVENTION A cooling structure for an integrated circuit according to the present invention is a cylindrical fin in which a flat plate having good thermal conductivity is fixed on an integrated circuit chip and a plurality of small holes are formed on the flat plate. Is formed, and a lid having a nozzle penetrating therethrough is attached to the upper part of the cylindrical fin. In the integrated circuit cooling structure of the present invention, a spiral groove may be formed inside the nozzle provided on the upper lid of the cylindrical heat sink. The cooling structure for an integrated circuit according to the present invention may have a certain angle with respect to the flat plate having the tip of the nozzle provided on the upper lid of the cylindrical heat sink fixed to the integrated circuit chip. In the integrated circuit cooling structure of the present invention, the nozzle provided on the lid can be connected to the nozzle for ejecting the refrigerant through the flexible hose.

The present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of an embodiment of the present invention. The heat sink 22 in this embodiment is composed of a flat plate 3, a cylindrical fin 4, an upper lid 7 and a secondary nozzle 6. A face-down integrated circuit chip 1 has a flat plate 3 having good heat conductivity bonded to a chip heat radiation surface via solder or a heat conductive adhesive 2. Further, the flat plate 3 is provided with a cylindrical fin 4, and a plurality of small-diameter holes 5 penetrating through the front and back are formed on the side surface of the fin 4. Further, an upper lid 7 having a secondary nozzle 6 penetrating therethrough is adhered to the upper end of the fin 4. The secondary nozzle 6 provided on the upper lid 7 is a flexible hose 8
It is connected to the primary nozzle 9 via. FIG. 2 is a sectional view of this embodiment. An insulating refrigerant such as fluorine carbide (for example, Fluorinert manufactured by 3M Co., Ltd.) proceeds in the direction of the arrow in the figure. The refrigerant that has passed through the primary nozzle 9 passes through the flexible hose 8 made of a rubber tube having excellent elasticity, and from the secondary nozzle 6 attached to the upper lid 7 of the heat sink 22 to the heat conduction inside the cylindrical fin of the heat sink 22. It collides with the flat plate 3 having good properties. The refrigerant colliding with the flat plate 3 removes heat from the integrated circuit chip 1 and flows out of the heat sink 22 through the small-diameter hole 5 formed in the side surface of the cylindrical fin 4. The heat sink 22 of the present embodiment has a fin shape in a cylindrical shape, so that the refrigerant can be brought into contact with all the heat transfer surfaces of the fins 4. In boiling cooling, it is important how the refrigerant in contact with the fins efficiently removes the heat of vaporization of boiling from the fins. However, when the fin temperature rises above a certain temperature, the boiling mode changes from nucleate boiling to film boiling. In the film boiling region, since a vapor film exists between the fins and the refrigerant, the heat of vaporization taken by the refrigerant from the fins is greatly reduced. Therefore, in order to prevent the boiling from transitioning to the film boiling, it is necessary to quickly remove the minute bubbles generated in the initial boiling stage from the fin heat transfer surface. It is important to provide a large number of stable bubble generation points. The heat sink 22 of this embodiment has a plurality of small-diameter holes 5 on the surface of the fin 4.
By opening the, a stable generation point of a large number of bubbles can be given thereto. In addition, an upper lid 7 is provided on the top of the fin 4.
By providing the above, after the refrigerant collides with the flat plate 3, the refrigerant can be forced to flow out from the hole 5 formed in the side surface of the fin 4 without flowing out from the upper portion of the fin. Therefore, the bubbles generated in the small-diameter holes 5 can be swept away,
The growth of bubbles can be suppressed and the transition to film boiling can be prevented. Further, the heat transfer area of the entire heat sink can be increased by allowing the refrigerant to pass through the small-diameter hole through the forced circle. As a result of experimental evaluation using the heat sink 22 of the present embodiment, the thermal resistance for cooling the integrated circuit chip 1 when the flow rate of the refrigerant is 11 / min to 21 / min shows that the conventional immersion jet cooling method shown in FIG. It was confirmed that the size can be reduced by 35 to 40% as compared with. Therefore, the power consumption is 100
It is also possible to cool an integrated circuit chip with a high output of W or more. In addition, the secondary nozzle 6 attached to the upper lid 7 of the heat sink of this embodiment is connected to the primary nozzle 9 via the flexible hose 8.
Therefore, the secondary nozzle can be installed in the center of the integrated circuit chip 1 regardless of the arrangement and size of the integrated circuit chips. Further, this allows the cooling device to have a certain degree of freedom in its collection, so that the problem of mounting error of the integrated circuit chip can be solved and the assembling work can be simplified. Further, the flexible hose 8 also has a role of relieving stress generated by thermal expansion of the integrated circuit chip 1 due to heat generation. FIG. 3 is a perspective view of another embodiment of the present invention, which has a structure in which a spiral groove is cut inside the secondary nozzle 11 of the heat sink 23. When the refrigerant that has passed through the primary nozzle 9 passes through the inside of the secondary nozzle 11,
It is given a swirling motion and collides with the heat dissipation surface of the integrated circuit while swirling spirally. Therefore, a swirling motion is added to the fins 4 of the heat sink due to the collision of the refrigerant inside, so that the efficiency of heat transport can be improved. Therefore, the cooling efficiency can be further increased as compared with the case of the embodiment shown in FIG. FIG. 4 is a sectional view of still another embodiment of the present invention.
In the embodiment of FIG. 4, the secondary nozzle of the heat sink 24 is composed of the curved tube secondary nozzle 14. The refrigerant having passed through the primary nozzle 9 is ejected from the curved tube secondary nozzle 14 and then collides with the heat dissipation surface of the integrated circuit while swirling along the inner surface of the cylindrical fin. Therefore, the effect of heat transport of the refrigerant can be enhanced as in the embodiment shown in FIG.

As described above, in the cooling structure for an integrated circuit according to the present invention, the flow of the coolant due to the jet flow is not obstructed by the fins of the heat sink, and the fine bubbles generated in the initial boiling stage are swept away. It is effective in improving the cooling efficiency of the integrated circuit, simplifying the assembly of the cooling device, and relaxing the thermal stress.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

2 is a cross-sectional view of the embodiment shown in FIG.

FIG. 3 is a perspective view of another embodiment of the present invention.

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

FIG. 5 is a perspective view of a heat sink used in a conventional integrated circuit cooling structure.

6 is a cross-sectional view of a conventional integrated circuit cooling structure using the heat sink shown in FIG.

[Explanation of Codes] 1 Integrated Circuit Chip 2 Solder or Thermally Conductive Adhesive 3 Flat Plate with Good Thermal Conductivity 4 Cylindrical Fin 5 Small Diameter Hole 6 Secondary Nozzle 7 Upper Lid 8 Flexible Hose 9 Primary Nozzle 10 Fin 11 Spiral Cutting Secondary nozzle 12 Bent tube secondary nozzle 21, 22, 23, 24 Heat sink

Claims (4)

[Claims] 1. A flat plate having good thermal conductivity is fixed on an integrated circuit chip, a cylindrical fin having a plurality of small holes is formed on the flat plate, and the fin is penetrated to the upper part of the cylindrical fin. A cooling structure for an integrated circuit, wherein a lid having a nozzle is attached. 2. The cooling structure for an integrated circuit according to claim 1, wherein a spiral groove is formed inside the nozzle provided on the upper lid of the cylindrical heat sink. 3. The cooling structure for an integrated circuit according to claim 1, wherein the tip of the nozzle provided on the upper lid of the cylindrical heat sink has a certain angle with respect to the flat plate fixed on the integrated circuit chip. 4. The nozzle provided on the lid is connected to a nozzle for ejecting a refrigerant through a flexible hose, 1, 2, or 3.
A cooling structure for an integrated circuit as described.