JPS62118552A - Cooling structure of integrated circuit - Google Patents

Abstract

PURPOSE:To reduce thermal resistance, by providing flat surface on the heat radiating surface of a substrate, fixing a heat radiating block, in which slits parts are provided at several places, with a fixing agent, fixing a water cooling jacket, which has a flat surface, on the surface of the heat radiating block with screws, thereby absorbing warping of the heat radiating block, and closely contacting the block of the water cooling jacket. CONSTITUTION:The opposite surface of a heat radiating block 5 with respect to the fixing surface is machined especially flatly, and a flat surface 5a is obtained. Several pieces of vertical slits are formed in both surfaces alternately, and slit parts 6 are provided at several places. A plurality of screw holes are used for attaching a water cooling jacket 8. Since the slit parts 6 are provided in both surfaces of the heat radiating block 5, the heat radiating block 5 is divided by the slits even if any surface, which is in parallel with the fixing surface, is observed. The block is divided into several parts. Even if warping deformation is yielded in each divided part, the effect to the other part is absorbed by the deformation of the soft slit part 6 due to a force, by which the warping on the side of a printed board 2 is recovered.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a cooling structure for an integrated circuit.

[Prior Art] As a conventional technology, there is a cooling device known in, for example, Japanese Patent Laid-Open No. 52-8776. The structure described here is
As shown in the figure, a micro package 20 having a plurality of integrated circuits mounted on a substrate 21 is mounted on a connector 22,
This is further mounted on the panel 23. Further, a heat exchanger 24 is placed on the surface of the substrate 21 opposite to the surface on which the integrated circuit is mounted, and a refrigerant liquid such as water is allowed to flow inside the heat exchanger 24 for cooling. FIG. 6 shows a longitudinal cross-sectional view of the heat exchanger 24, which has a flexible spike wall 26 on the bottom surface. Here, the heat dissipation tube 25 (see FIG. 5), which is the surface of the micro package 20 opposite to the integrated circuit mounting surface, is designed to absorb heat that is sometimes applied when forming multilayer printed wiring on the substrate 21 or when installing an integrated circuit chip. Therefore, the surface is not necessarily flat. However, in order to efficiently transfer the heat generated in the integrated circuit, it is necessary to bring the flexible wall 26 of the heat exchanger 24 into close contact with the heat radiation surface 25 and reduce the gap between the two. Lack of flatness such as φ deformation is undesirable. However, in this reference, the flexible wall 26 is deformed by the pressure of the water flowing inside the heat exchanger 24 as shown by the dashed line in FIG. .

[Problems to be solved] -1; In the conventional cooling device described above, the flexible wall 26 provided on the bottom of the heat exchanger 24 is made of a particularly thin copper or the like in order to have flexibility. In this reference, it is said that a thickness of 0.05 mm to 0.25 mm is suitable. Because such a thin plate is used, it is not possible to increase the pressure that is pressed against the heat exchanger 24, which is one of the factors that determines the thermal resistance, that is, the water pressure. It was a hindrance. In addition, the heat exchanger 24 is operated when replacing the micro package 20, and since the strength of the flexible wall 26 is weak, it is necessary to handle it with care, and if it is mistaken, water leakage may occur, which is a very serious problem. There was a problem in that there was a risk of causing

[Means for solving the problems] The present invention solves the problems described in -, and includes a substrate,
The integrated circuit mounted on the substrate -1- is fixed to the surface of the substrate opposite to the integrated circuit mounting surface with an adhesive, and the surface opposite to the fixed surface is the movable surface, and the surface is vertical. A sleeve i portion is provided in which several slits are cut alternately from the fixing surface and the opposite side thereof, and the screw hole i17. A plate-shaped heat dissipation block and a through hole at a position corresponding to the screw hole, and by passing a screw through the through hole and tightening the screw into the screw hole, an additional issue can be stacked on the flat surface of the heat dissipation block. , and a heat exchanger whose surface in contact with the flat surface is flat. [Embodiment] Next, an embodiment thereof will be described with reference to the drawings.

FIG. 1 is an exploded perspective view of an embodiment of an integrated circuit cooling structure according to the present invention, and FIG. 2 is a cross-sectional view of the structure.

1 and 2, a large number of integrated circuits 3 are arranged on the side surface of a motherboard 9 of a printed circuit board 2, and both are electrically and mechanically connected and supported. A heat dissipation block 5 is fixed to the surface of the printed circuit board 2 opposite to the surface on which the integrated circuit 3 is mounted using an adhesive 4 such as a semicircular adhesive or a silver-containing adhesive with good thermal conductivity, and the two are integrated to form the module 1. be done. The heat dissipation block 5 has a flat surface 5 with the surface opposite to the fixed surface processed to be particularly flat.
A, and several slit portions 6 are provided by alternately cutting several perpendicular slits from both sides, and there are a plurality of screw holes 7, which are used for attaching a water cooling jacket 8, which will be described later. When using solder or the like as the adhesive 4 for fixing the heat dissipation block 5, the fixing surface of the printed circuit board 2 is metalized in advance. By fixing, the warpage and waviness of the printed circuit board 2 and the heat dissipation block 5 explained in the prior art are avoided.
The gap caused by the warping and deformation of the bonding surface is filled with the bonding agent 4. If the materials of the printed circuit board 2 and the heat dissipation block 5 have different coefficients of thermal expansion, warping may occur due to the temperature difference during fixation or actual use.

However, in the present invention, by providing the heat dissipation block 5 with the slit portion 6 in which slits are inserted from both sides,
As shown in Fig. 3, the heat dissipation block 5 is divided by slits and divided into several parts even when viewed from a plane parallel to the fixed surface, so even if each part is warped and deformed, The influence of the deformation of the portion is absorbed by the soft slit portion 6 being deformed by the force that undoes the warpage on the printed circuit board 2 side. Therefore, the printed circuit board 2 and heat dissipation block 5 shown in FIG.
, l 7 ), the curvature M can be kept small (11<u2) because the span of each part is small. Therefore, if the material of the heat dissipation block 5 is a metal with good thermal conductivity, the thermal expansion coefficient will be lower than that of the printed circuit board 2.
Since it may be slightly different from the above, there is a wide range of choices, and inexpensive ones can be used.

The module 1 has a motherboard 9 as shown in FIGS. 1 and 2.
When the frame-shaped holder 11 presses the outer edge of the module 1, the module 1 is electrically connected to the connector 10 and held. Furthermore, a water cooling jacket 8 is stacked on the upper surface of the heat radiation block 5 of the module l, that is, the flat surface 5a, and a plurality of screws 12 are passed through the through holes 13 of the water cooling jacket 8 and tightened into the screw holes 7 of the heat radiation block 5, so that both are joined and fixed. The surface of the water cooling jacket 8 that comes into contact with the heat radiation block 5 is particularly processed to be flat and has a flat surface 8a. screw 12
1liJ of the heat dissipation block 5 by being tightened downward.
The warp of 5a is absorbed by the slit part 6, and is forcibly connected to the flat surface 8a of the water cooling jacket 8, and the 3
1i - The gap between the flat surfaces 5a and 8a, that is, the gap between the joint surfaces becomes almost zero.

Next, the operation will be explained. water cooling jacket 8
It flows into an internal conduit, Iceberg+-1'ii'15.

Heat generated in the integrated circuit 3 is transmitted to the printed circuit board 2 and transferred to the heat dissipation block 5 through the adhesive 4. As described above, the adhesive 4 fills the gap between the printed circuit board 2 and the heat radiation block 5 and there is no air layer, so that the thermal resistance between the board 2 and the heat radiation block 5 can be reduced.

Since the heat dissipation block 5 and the water cooling jacket 8 are firmly attached to each other by the screws 12, the thermal resistance can also be reduced.

In this way, it is possible to reduce the thermal resistance from the 8 sources to the water cooling jacket 8 that performs heat exchange. Further, the heat exchange surface of the water cooling jacket 8 does not need to be a thin plate in order to have flexibility +1 as in the conventional case, but is made of a thick plate, so it has sufficient mechanical strength. In this embodiment, a water-cooling system equipped with a water-cooling jacket 8 has been described, but an air-cooling system can also be realized by installing a heat sink with fins and a flat bottom surface.

[Effects of the Invention] As explained above, the present invention has a heat dissipating block that has a flat heat dissipating surface of a substrate and has slits in several places, and fixes the heat dissipating block with an adhesive, so that the surface of the heat dissipating block is fixed. Since the water cooling jacket with a flat surface on top is tightened with screws, the slit absorbs the warpage of the heat dissipation block and brings it into close contact with the water cooling jacket, reducing thermal resistance.
Therefore, it is not necessary to use a material having the same coefficient of thermal expansion as that of the printed circuit board, so the cost can be reduced. In addition, the water cooling jacket, which is a heat exchanger that is operated during maintenance, can be constructed of a thick plate, making it mechanically strong.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of an embodiment of an integrated circuit cooling structure according to the present invention, FIG. 2 is a cross-sectional view of the structure shown in FIG. Figure 5 is an exploded perspective view of a conventional integrated circuit cooling structure; The figure is a cross-sectional view of a heat exchanger with a conventional structure. l: Module 2: Printed circuit board 3: Integrated circuit 4: Adhesive agent 5: Heat dissipation block 5a, 6d: Flat surface 6: Slit part 7: Screw hole 8: Water cooling jacket 9: Motherboard lO: Connector l: Holder 12: Screw 13 : Through hole 14: Water inlet [1 tube 15: Water 1 old 1 tube 20: Micro package

Claims (1)

[Claims] A substrate and an integrated circuit mounted on the substrate are fixed to the surface of the substrate opposite to the integrated circuit mounting surface with an adhesive, and the surface opposite to the fixed surface is a flat surface and is perpendicular. A flat heat dissipation block is provided with a slit portion in which several slits are cut alternately from the fixed surface and the opposite side thereof, and has a screw hole, and a through hole is provided at a position corresponding to the screw hole. and a heat exchanger that is mounted on the flat surface of the heat dissipation block by passing screws through the through holes and tightening them into the screw holes, and having a flat surface in contact with the flat surface. A cooling structure for an integrated circuit characterized by: