Cooling device for semiconductor elements

ABSTRACT

A cooling device for cooling a semiconductor element includes at least one cold plate utilizing a copper plate for cooling a semiconductor element, a condenser utilizing a plurality of flat micro-tubes, a refrigerant pump for circulating a refrigerant, and a fan for cooling the condenser. The cold plate, the condenser, and the refrigerant pump are fluid connected to define a refrigerant circulating circuit.

INFORMATION

DETAILED DESCRIPTION OF THE INVENTION

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

This application is based on an application No. 2002-123990 filed Apr. 25, 2002 in Japan, the content of which is herein expressly incorporated by reference in its entirety.

Referring first to FIG. 1 showing a refrigerating cycle according to a preferred embodiment of the present invention, a cooling device shown therein includes a plurality of (for example, two) cold plates in the form of a copper plate for cooling one or more highly exothermic semiconductor elements, that is, semiconductor elements tending to emit a substantial amount of heat when in operation, a flat micro-tube condenser , and a refrigerant pump , all connected in series with each other. The condenser is adapted to be cooled by a fan , and a refrigerant is filled in the refrigerating cycle.

The cooling device is so designed that the refrigerant emerging first from the condenser is supplied towards the cold plates by the refrigerant pump . The cold plates so supplied with the refrigerant absorb heat emitted from the highly exothermic semiconductor elements and, in the course of absorption of the heat, a change in phase from a liquid refrigerant to a vapor refrigerant takes place within the cold plates . The vapor refrigerant is then supplied towards the condenser and cooled by the fan , resulting in a change in phase from the vapor refrigerant to the liquid refrigerant.

According to this embodiment, since cooling of the highly exothermic semiconductor elements is carried out by the utilization of the phase change of the refrigerant, a highly efficient cooling can be achieved.

Also, since the use has been made of the flat microtube condenser and the cold plates made of copper, an efficient heat exchange and heat transfer can be achieved and, hence, it is possible to manufacture the cooling device in a compact size.

The condenser referred to above is made up of flat micro-tubes arranged in three rows and has a refrigerant inlet and a refrigerant outlet. The refrigerant inlet through which the refrigerant is introduced into the flat micro-tube condenser is communicated with one of the flat micro-tubes that is positioned remote from the fan whereas the refrigerant outlet from which the refrigerant is discharged outwardly of the flat micro-tube condenser is communicated with another flat micro-tube that is positioned close to the fan . Accordingly, a current of air induced by the fan and a temperature difference induced in the flat micro-tube condenser can be effectively evolved due to the plural rows of the flat micro-tubes to thereby achieve a high performance heat exchange. Also, since the cold plates are connected in series with each other and are each made of copper having a high heat conductivity, the semiconductor elements can be sufficiently cooled, even though they emit different quantities of heat, thereby suppressing any undesirable and/or abnormal increase of temperature of the semiconductor elements.

Although two cold plates are illustrated in FIG. 1, only one cold plate may be employed.

FIG. 2 illustrates the details of the flat micro-tube condenser . As shown therein, the flat micro-tube condenser includes a refrigerant suction tube , fluid connected with an upper region of an inlet header , and a refrigerant discharge tube fluid connected with a lower region of an outlet header . A plurality of (for example, three) flat micro-tubes are disposed parallel to each other between the inlet and outlet headers and , with a multiplicity of heat radiating fins disposed between the neighboring flat micro-tubes . The flat micro-tube condenser is of the structure in which a two-phase refrigerant, i.e., a mixture of the vapor refrigerant and the liquid refrigerant, which enters through the upper region of the inlet header , flows uniformly through those flat micro-tubes and only the liquid refrigerant is subsequently discharged from the lower region of the outlet header . According to this embodiment, since the refrigerant can uniformly flow through the flat micro-tube condenser , utilization of the flat micro-tube condenser can be effectively maximized, and since only the liquid refrigerant can be discharged from the outlet, not only can reduction of the flow, which would result from an entrapment of the gas by the refrigerant pump , be avoided, but a stable cooling performance can be also obtained.

FIG. 3 illustrates the details of each of the cold plates . The respective cold plate includes a copper plate having a plurality of parallel passages defined therein, with copper tubes and soldered thereto while generally U-shaped copper tubes , and are also soldered to the copper plate so that a tortuous fluid passage can be defined in the cold plate . As such, the respective cold plate can be assembled merely by soldering of the tubes to the copper plate having the parallel passages defined therein.

FIGS. 4A and 4B illustrate a modified form of each of the cold plates as viewed in a transverse sectional representation and a top plan representation, respectively. In this modification, the copper plate has a flat cavity defined therein with refrigerant tubes and soldered thereto in communication with the cavity. This modified cold plate is particularly advantageous in that since there is an increased surface area of contact of the refrigerant within the cavity with the copper plate , a highly efficient cooling can be achieved.

Although the present invention has been fully described by way of examples with reference to the accompanying drawings, it is to be noted here that various changes and modifications will be apparent to those skilled in the art. Therefore, unless such changes and modifications otherwise depart from the spirit and scope of the present invention, they should be construed as being included therein.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objectives and features of the present invention will become more apparent from the following description of a preferred embodiment thereof with reference to the accompanying drawings, throughout which like parts are designated by like reference numerals, and wherein:

FIG. 1 is a schematic diagram showing a refrigerating cycle performed by a cooling device according to a preferred embodiment of the present invention;

FIG. 2 is a schematic diagram showing the details of a flat micro-tube condenser used in the cooling device;

FIG. 3 is a schematic diagram showing the details of each of cold plates used in the cooling device; and

FIG. 4A is a sectional view of a modified form of each of the cold plates; and

FIG. 4B is a top plan view of the cold plate of FIG. A.

CLAIMS

1. A cooling device for cooling a semiconductor element, which comprises: a first cold plate utilizing a copper plate for cooling the semiconductor element; a condenser utilizing a plurality of flat micro-tubes; a refrigerant pump for circulating a refrigerant, the first cold plate, the condenser and the refrigerant pump being connected in series in this order to define a refrigerant circulating circuit; and a fan for cooling the condenser, wherein the plurality of flat micro-tubes are arranged such that the refrigerant supplied from the first cold plate enters one of the flat micro-tubes positioned remote from the fan and emerges outwardly from another of the flat micro-tubes positioned close to the fan.

2. The cooling device according to claim 1, wherein an inlet through which the refrigerant enters the condenser is positioned higher than an outlet through which the refrigerant emerges outwardly from the condenser.

3. The cooling device according to claim 1, further comprising a second cold plate connected in series with the first cold plate.

4. The cooling device according to claim 1, wherein the first cold plate has a plurality of fluid passages defined therein, all of the fluid passages being connected in series with each other by at least one copper tube for passage of the refrigerant therethrough.

5. The cooling device according to claim 1, wherein the first cold plate has a flat cavity defined therein, through which the refrigerant flows.

6. A cooling device according to claim 1, said refrigerant circulating circuit including two-phase refrigerant which cools the semiconductor element.

7. A cooling device according to claim 1, wherein cooling of the semiconductor element is carried out by utilization of a phase change of the refrigerant.

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