JP2768108B2 - 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 for electric 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. It relates to the structure of jet cooling.

[0002]

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

FIG. 5 shows the shape of a heat sink 21 used in a conventional cooling structure for an integrated circuit. In the conventional heat sink 21, the fin 10 having a constant pitch is
Solder or heat conductive adhesive 2
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 a conventional cooling structure is shown in FIG. The nozzle side, which is the upper end of the heat sink 21, has an open structure. The refrigerant jetted from the primary nozzle 9 collides perpendicularly with the central part of the surface of the integrated circuit chip 1 of the heat sink 21, and then rebounds and flows out of the upper end of the heat sink 21.

[0004]

In the conventional cooling structure for an integrated circuit, the refrigerant ejected from the nozzle flows along the flow of the arrow shown in FIG. 6, and the central portion of the integrated circuit chip is located on the fin surface. Bubbles generated by boiling can be removed. For this reason, the cooling efficiency can be increased in the central part of the integrated circuit chip, but in the peripheral part of the chip, the fin in the central part of the heat sink becomes an obstacle, so that the flow of the refrigerant is obstructed, and the cooling efficiency can be increased significantly. Can not. Therefore, there arises a problem that the surface temperature of the integrated circuit chip differs between the central part and the peripheral part of the chip and the cooling effect is small.

[0005]

According to the cooling structure for an integrated circuit of the present invention, a flat plate having good thermal conductivity is fixed on an integrated circuit chip, and a cylindrical fin having a plurality of small-diameter holes formed on a side surface is provided in front of the cooling structure.
A lid having a nozzle formed on the flat plate and having a penetrating nozzle mounted on the upper portion of the cylindrical fin is provided.
It is characterized by being ejected into cylindrical fins .

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

In the integrated circuit cooling structure of the present invention, the tip of the nozzle provided on the upper lid can be given an angle with respect to the flat plate fixed on the integrated circuit chip.

In the integrated circuit cooling structure of the present invention, a nozzle provided on the upper lid can be connected to a nozzle for jetting a coolant through a flexible hose.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

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

In this embodiment, the heat sink 22 is a flat plate 3,
It comprises a cylindrical fin 4 , an upper lid 7 and a secondary nozzle 6. The face-down integrated circuit chip 1 has a chip heat dissipation surface and a flat plate 3 having good heat conductivity bonded to it via solder or a heat conductive adhesive 2. The flat plate 3 has a cylindrical shape.
The fin 4 is provided, and a plurality of small-diameter holes 5 penetrating the front and back sides are formed on the side surface of the fin 4 . Furthermore Fi
An upper lid 7 having a penetrating secondary nozzle 6 is bonded to the upper end of the housing 4 . The secondary nozzle 6 provided on the upper lid 7 is connected to a primary nozzle 9 via a flexible hose 8.

FIG. 2 is a sectional view of this embodiment. An insulating refrigerant such as fluorocarbon (for example, Fluorinert manufactured by 3M) proceeds roughly in the direction of the arrow in the figure. The refrigerant that has passed through the primary nozzle 9 passes through a flexible hose 8 made of a rubber tube or the like having excellent elasticity, and from the secondary nozzle 6 attached to the upper lid 7 of the heat sink 22 to the cylindrical fin of the heat sink 22.
Impinging the inside of good thermal conductivity flat plate 3. The refrigerant that collides with the flat plate 3 deprives the integrated circuit top 1 of heat and removes heat from the cylindrical fin.
4 through the small-diameter hole 5 formed in the side surface of the heat sink 22.
To the outside of the

The heat sink 22 of this embodiment has a fin shape.
It can be contacted refrigerant to Zenden'netsu surface of the fin 4 by a a cylindrical.

[0014] In boiling cooling is important that any refrigerant in contact with the fins take better how efficiently the heat of vaporization boiling from the fins. However, when the temperature of the fin 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 fin and the refrigerant, the heat of vaporization taken by the refrigerant from the fin is greatly reduced. Therefore, in order to prevent boiling from transiting to film boiling, it is necessary to quickly remove minute bubbles generated at the beginning of boiling from the heat transfer surface of the fin . It is important to provide many stable bubble generation points.

In the heat sink 22 of this embodiment, a plurality of small diameter holes 5 are formed in the surface of the fin 4 so that a stable generation point of a large number of bubbles can be given to the hole.

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 filtered.
The fins 4 can be forcibly discharged from the holes 5 formed on the side surfaces of the fins 4 without being discharged from the upper portions of the fins . For this reason, bubbles generated in the small-diameter holes 5 can be wiped out, and 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 forcibly passing the refrigerant through the small-diameter hole.

As a result of an experimental evaluation using the heat sink 22 of this embodiment, the flow rate of the refrigerant was 11 / min to 21 / mi.
n, the thermal resistance for cooling the integrated circuit chip 1 is 35 to 35 in comparison with the conventional immersion jet cooling method shown in FIG.
It was confirmed that it could be reduced by 40%. Therefore, a high-output integrated circuit chip having a power consumption of 100 W or more can be cooled.

Further, the secondary nozzle 6 attached to the upper lid 7 of the heat sink of the present embodiment is connected to the primary nozzle 9 via a flexible hose 8, and therefore, regardless of the arrangement and size of the integrated circuit chips. Instead, the secondary nozzle can be installed at the center of the integrated circuit chip 1. In addition, since the cooling device can be provided with a certain degree of freedom, the problem of mounting errors of the integrated circuit chip can be solved and the assembling operation can be simplified. Further, the flexible hose 8 also has a role of relieving stress generated by thermal expansion due to heat generation of the integrated circuit chip 1.

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 that has passed through the primary nozzle 9 is given a swirling motion when passing through the interior of the secondary nozzle 11, and collides with the heat radiation surface of the integrated circuit while spiraling. Therefore, since the swirling motion is applied to the collision of the refrigerant inside the fins 4 of the heat sink, the efficiency of heat transport can be increased. For this reason, the cooling efficiency can be further enhanced as compared with the embodiment shown in FIG.

FIG. 4 is a sectional view of another embodiment of the present invention. In the embodiment of FIG. 4, the secondary nozzle of the heat sink 24 is constituted by the bent tube secondary nozzle 14. After the refrigerant that has passed through the primary nozzle 9 is ejected from the bent tube secondary nozzle 14, the refrigerant collides with the integrated circuit heat radiation surface while rotating along the inner surface of the cylindrical fin . Therefore, the effect of the heat transfer of the refrigerant can be enhanced as in the embodiment shown in FIG.

[0021]

Cooling structure of an integrated circuit of the present invention as described above, according to the present invention, the refrigerant by the jet flow of the heat sink off
The cooling efficiency of the integrated circuit is improved by eliminating fine bubbles generated at the beginning of boiling without being disturbed by the heat sink, and it is also effective in simplifying the assembly of the cooling device and relieving thermal stress.

[Brief description of the drawings]

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

FIG. 2 is a 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 for a conventional cooling structure of an integrated circuit.

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

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Integrated circuit chip 2 Solder or heat conductive adhesive 3 Flat plate with good heat conductivity 4 Cylindrical fin 5 Small diameter hole 6 Secondary nozzle 7 Top lid 8 Flexible hose 9 Primary nozzle 10 Fin 11 Spiral cutting secondary nozzle 12 Bending Pipe secondary nozzle 21, 22, 23, 24 Heat sink

Claims (4)

(57) [Claims] 1. A flat plate having good thermal conductivity is fixed on an integrated circuit chip, and a cylindrical fin having a plurality of small-diameter holes formed on a side surface thereof is formed on the flat plate. A cooling structure for an integrated circuit, wherein an upper lid having a penetrated nozzle is attached, and a coolant is jetted from the nozzle to the cylindrical fin. 2. A cooling structure for an integrated circuit according to claim 1, wherein a spiral groove is formed inside a nozzle provided on the upper lid . 3. The integrated circuit cooling structure according to claim 1, wherein the tip of the nozzle provided on the upper lid has a certain angle with respect to the flat plate fixed on the integrated circuit chip. 4. A cooling structure for an integrated circuit according to claim 1, wherein the nozzle provided on the upper lid is connected to a nozzle for jetting a coolant through a flexible hose.