JPH0423356Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The invention has a flow path for a coolant inside,
The present invention relates to a board that can absorb heat generated by mounted resistors, IC chips, and other elements or modules and radiate the heat to the outside.

<Prior Art> Recently, with the development of electronics, the integration of electronic circuits has progressed, and mixed integrated circuits in which a large number of elements and modules such as semiconductors, resistors, and capacitors are combined on the same substrate are widely used. If the substrate and surrounding temperature rise due to the heat generated by these elements, the functionality of the electronic circuit will be significantly impaired. For this reason, metal foil wiring is pasted or laminated on a highly thermally conductive resin insulating layer formed on a metal substrate, and the heat generated from each element is conducted to the metal substrate side and radiated. , a board equipped with a heat radiator that is forcedly air-cooled by a fan motor or the like is known. However, these substrates have physical limitations in their cooling effect, making it difficult to achieve high integration of electronic circuits.

Therefore, in the specification of Japanese Patent Application No. 190372/1982, the applicant of the present application proposed a method for transmitting heat to the surface of a cold plate made of a metal plate provided with a channel for circulating a liquid refrigerant that can be connected to an external cooling system. We are proposing a substrate coated with thermal resin.

However, in the above-mentioned substrate, when the two plates and the fins for forming the coolant flow path between them are joined by heat pressure welding, the difference in coefficient of thermal expansion occurs on the joint surface. There was a problem in that failures occurred due to distortion caused by.

<Problems to be Solved by the Invention> Therefore, an object of the present invention is to provide a liquid-cooled substrate that is relatively easily manufactured without causing distortion and has a high cooling effect.

<Means for Solving the Problems> According to the present invention, the above-mentioned object is to provide two thin plates made of an electrically insulating material having high thermal conductivity, on at least one of which a circuit element is provided; A corrugated sheet formed by bending a thin metal plate sandwiched between two thin sheets to form ridge-like irregularities, and a frame material surrounding the corrugated sheet are overlaid and integrally joined. , a liquid-cooled substrate in which a flow path for a coolant connectable to an external cooling system is formed between the two thin plates and cooled almost entirely; This is achieved by providing a liquid-cooled substrate characterized in that the top portion is provided with a plurality of slits extending in a direction perpendicular to the direction in which the ridges extend.

<Function> According to the present invention, by integrally forming an electrically insulating material with high thermal conductivity, a circuit pattern can be directly formed on the surface thereof, or a laminated structure can be formed, and chips and modules can be attached. Therefore, a high cooling effect can be obtained. Since the slits allow the corrugated sheet to expand and contract in the direction in which the ridges extend, thermal strain due to differences in coefficients of thermal expansion can be absorbed.

<Embodiments> The present invention will now be described in detail with reference to specific embodiments with reference to the accompanying drawings.

As shown in FIG. 1, a substrate 1 according to the present invention includes:
It is composed of thin plates 2 and 3 arranged parallel to each other and separated from each other, and a frame member 4 sandwiched between them. Both thin plates 2 and 3 and the frame member 4 are made of ceramic materials such as alumina, silicon carbide, and aluminum nitride ceramics, which have high thermal conductivity and electrical insulation properties. This ceramic material is
It is preferable to use a material having a coefficient of thermal expansion close to that of the chip or module to be mounted. Furthermore, inside the substrate 1, there are provided fins 5.
A plurality of channels 6 are formed to uniformly distribute liquid refrigerant introduced from an external cooling system.

The fins 5 are made of a corrugated sheet formed by bending a thin metal sheet to form regular ridge-like irregularities extending parallel to each other. As clearly shown in FIG. 2, the fins 5 have a plurality of grooves formed in the direction of the refrigerant flow path, that is, the grooves formed in the shape of ridges, along the extending direction of the protrusions, and in the direction perpendicular to the direction. slit 7
are formed at equal intervals. Thin plates 2, 3, frame material 4
The fins 5 are integrally joined so that the inside thereof is kept liquid-tight. Specifically, they are bonded using an adhesive, or by heating and pressurizing by brazing or diffusion bonding. In this case, the metal fin 5 is connected to the thin plate 2 made of ceramic material,
Although there is a possibility that distortion may occur in the joint surface due to the difference in coefficient of thermal expansion between the fins 5 and 3, this thermal distortion can be absorbed by the slits 7 provided in the fins 5.

Further, as shown in FIG. 1, a circuit pattern is formed on the surface of the substrate 1 by a known method, and an element 8 such as a chip is mounted thereon, or a ceramic module is attached with screws or the like. Further, it is also possible to manufacture a substrate by laminating several layers of circuit patterns on the surfaces of the thin plates 2 and 3 in advance and joining them as described above.

An injection pipe 9 and a discharge pipe 10 for the refrigerant are provided in the upper and lower parts of the thin plate 3, respectively.
The injection pipe 9 and the discharge pipe 10 are each connected to an external cooling system to form a closed circuit. As shown by the arrow in FIG.
The heat flows into the inside of the substrate 1 from above, and each element 8 that is transmitted through the plate material 2 moves upward in the flow path 6 while absorbing the generated heat, and is discharged from the discharge pipe 10. In this case, if a heat medium with a large volume change due to heat, such as silicone oil, is used as the liquid refrigerant, a gravity circulation system can be used in which the liquid refrigerant naturally circulates as the temperature rises due to endothermic action. Further, the substrate can be cooled by forcibly circulating a coolant such as pure water using a pump or the like.

<Effects of the invention> As described above, according to the invention, the substrate is formed of a material having high thermal conductivity and electrical insulation, such as ceramic material, and a flow path for liquid refrigerant is provided inside. Since circuit patterns can be formed directly on the board and chips, ceramic modules, etc. can be attached, the heat generated from each element is directly transferred to the coolant, significantly improving the cooling effect of the board, and enabling high integration of electronic circuits. can be achieved.

In addition, this board is formed by integrally joining a thin plate and frame material made of ceramic material with metal fins by brazing or diffusion bonding, so it is possible to easily and inexpensively produce a board of relatively large size. can be manufactured. The slits formed in the fins absorb thermal distortion caused by hot pressure welding during bonding, so unnecessary stress is not applied to the bonding surfaces, making it possible to further stabilize quality.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view showing an embodiment of a substrate according to the present invention. FIG. 2 is a partially enlarged sectional view of the fins shown along the flow path direction of the refrigerant. 1...Substrate, 2, 3...Thin plate, 4...Frame material, 5
...Fin, 6...Flow path, 7...Slit, 8...
...chip, 9...injection pipe, 10...discharge pipe.

Claims (1)

[Claims for Utility Model Registration] Two thin plates made of an electrically insulating material with high thermal conductivity, at least one of which is provided with a circuit element, and a thin metal plate sandwiched between the two thin plates are folded. A corrugated sheet formed by bending to form ridge-like irregularities and a frame material surrounding the corrugated sheet are overlaid and integrally joined, and the cooling material is connectable to an external cooling system. A liquid-cooled substrate in which a flow path is formed between the two thin plates to cool the entire surface, wherein a flow path is formed between the thin plates at each bottom and at each top of the unevenness of the corrugated plate in a direction perpendicular to the extending direction of the ridges. A liquid-cooled substrate characterized by having a plurality of slits along the substrate.