JPS6184045A - Integrated circuit cooling structure - Google Patents

Abstract

PURPOSE:To produce a cooling structure with excellent radiating efficiency by a method wherein a heat conductive bar provided with a cylindrical plane with conical hole in the central part to be screwed up and down vertically and a conical axle with a conical hole and a female screw to be driven as well as a slot in the female screw direction passing through the axle center is inserted into a thermal conductive plate to be driven by a male screw. CONSTITUTION:A conical axle 9 with a female screw 8 in the central part to be driven along a conical hole is fixed to a cylinder 10 with the conical hole and a slot 6 passing through the central part leaving a little bit non cut part while a basic plane 7 is brazed. The conical axle 9 is screwed up along the cylinder 10 by means of driving a male screw 16 into a female screw 8. As soon as the cylinder 10 is fully tightened, the component in contact pressure in the radial direction expands the slot width 6 to fix the cylindrical plane of assembled body (thermal conductive bar 15) on the inner plane of a thermal conductive plate 17 by means of thrusting the former. Through these procedures, a fine gap may be set up between the basic plane 7 and the surface of all ICs to fill a jacket 30 with cooling water. In such a constitution, a cooling structure with excellent radiating efficiency insulated from water may be produced and the thermal resistance may be further reduced by means of filling the gap 14 with electric insulating and thermal conductive filler.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cooling structure for integrated circuits such as LSI packages.

[Conventional technology]

Conventionally, the method used to cool ICs mounted on printed wiring boards or ceramic substrates is to use a heat sink (hereinafter referred to as a heat sink) attached to the IC case or case. This has been achieved by blowing air at room temperature or air whose temperature has been lowered using a cooling device. However, air is not necessarily the best refrigerant to carry the heat dissipated from the IC out of the device. The first reason is that the thermal resistance between the solid IC case or heat tank and air is large, and the temperature difference between them becomes large. The temperature of the air must be lowered. For example, information processing equipment (hereinafter referred to as the equipment) requires large-scale air conditioning equipment to lower the temperature of the air in the room in which it is installed.

Next, the second reason is that the air Ii heat capacity is small and a little p
Since the temperature rises at Arrt, the maximum amount of air must be sent to M position in order to carry out the heat from the Oto from inside the device. However, in recent years, high-performance information processing equipment has been developed to increase its processing speed by increasing the performance rate f, increasing the operating speed of ICs by increasing power consumption, or reducing signal propagation delay time by increasing the density of packaging. This results in an increase in heat generation and heat generation density.

Therefore, in the conventional technology, air conditioning equipment with a high cooling capacity is required in the room in which the device is installed for cooling, and this is due to the same mounting density inside the device. A blower with a high air volume and high discharge pressure is required to reduce the air passage inside the equipment and to discharge the heat of the dog to the outside of the equipment. It is extremely difficult to evenly distribute high-velocity airflow inside the device, which causes a temperature rise due to insufficient cooling of the IC, which also reduces the reliability of the device. there were.

In order to solve these drawbacks, a cooling structure using a liquid as a refrigerant as shown in FIG. 5 has been proposed.

That is, the piston 23 is pressed against the semiconductor chip 21 mounted on the substrate 20 by the spring 25, and the heat generated by the semiconductor chip 21 is transferred from the piston 23 to the minute gap 24.
→The heat conduction plate 26 receives refrigerant 271 which is injected from the refrigerant intake port 28 and discharged from the discharge port 29.
It is cooled by C.

However, the cooling structure shown in FIG. 5 also has significant drawbacks. First, the first K: Since the semiconductor chip 21 and the metal piston 23 are in mechanical contact, the refrigerant 27
and the semiconductor chip 21 cannot be electrically insulated. The refrigerant 27 is connected to the ground of the compressor and refrigerant delivery bonder through a heat exchanger, etc., but this ground is very noisy and is not suitable for the semiconductor chip 21 unless an insulator outside the water line is used for the cooling ff 27. This is an extremely dangerous situation.

Since the piston 723 is pressed against the spring 2 by the elastic force of the spring 25, the piston 23 and the spring 25 form a vibration system in which wQ=+.

Here, wou #oscillation angular frequency frequency i is the spring constant of the spring 25, and m indicates the quality of the piston 23. Therefore, if an external force such as an impact containing a resonance frequency component is applied, the piston 23 may vibrate and the semiconductor chip 21 may be destroyed. Since pressure is constantly applied to the solder 22 for connection to the substrate 20 at v, 3, creep deformation occurs. Wait, this is noticeable when using low-temperature solder.

[Problems to be solved]

In the present invention, the air used as the cooling U is not very efficient, and therefore requires high-capacity air conditioning equipment, or the heat generated from the semiconductor chip is transferred to the semiconductor chip. The purpose of the present invention is to provide a cooling structure that efficiently discharges heat to the outside of the device and has low thermal resistance without bringing solid matter into contact with the chip or its case, and without intervening inefficient air as a refrigerant.

[Means for solving problems]

The integrated circuit cooling structure of the present invention includes a substrate, an integrated circuit mounted on the substrate, a bottom surface facing the integrated circuit with a small gap therebetween, and a bottom surface that is perpendicular to the substrate (slidable surface). A cylindrical surface with a conical hole in the center that forms one element of the bevel pair, a conical shaft that is bored in the direction of the base plate and has an internal thread that is slidable in the conical hole, and a shaft of the three conical parts. A heat conductive rod having a notch extending through the core and parallel to the direction of the female thread, a heat conductive plate having a hole forming a sliding pair with a cylindrical surface of the heat conductive rod, and a hole of the heat conductive rod. The above-mentioned conventional problems are solved by having a male thread inserted into the threaded part.

〔Example〕

Next, one embodiment of the present invention will be described in detail with reference to FIGS. 1 to 4. FIG. 1 shows a cross-sectional view of an embodiment of the present invention.

Referring to FIG. 1, an integrated circuit 11 mounted on a substrate 12
The bottom surfaces of the heat conductive rods 15 are opposed to each other with a minute gap 14 in between.

In the present invention, the biggest factor determining the cooling capacity is the thickness of the minute gap 14, and making it thinner is the most important issue. However, since the integrated circuit 11+'' is generally attached to the substrate 12 by the connecting solder 13, the thickness of the solder varies greatly and the range usually exceeds 100 μm, and it is impossible to reduce the minute gap 14 to less than this value. It is.

Therefore, in the present invention, after the integrated circuit 1 is soldered to the substrate 12, a spacer such as an extremely thin film is placed on the substrate 11, the substrate frame 18 and the heat conductive plate 17 are fixed with the screws 19, and the heat conductive rod 15 is fixed. The heat conduction rod 15 is fixed to the heat conduction plate 17 by tightening the male screw 16 inserted into the female threaded part 8 of the heat conduction rod 15 by inserting it and pressing it against the spacer on ll, and then removing the screw 19. The heat conduction plate 17 and the board frame 18
By separating the above-mentioned spacers and reassembling them, it is possible to realize a minute gap with the same thickness as the spacer.

Here, the mechanism by which the heat conduction fi 15 is fixed to the heat conduction plate 17 will be described in detail. FIG. 2 is a divided and enlarged view of the elements constituting one heat conduction rod.

It has a cylindrical shape with a conical hole inside, and a groove 6 is cut through the center, leaving a slight uncut portion on the bottom.

Inside the notched cylinder 10, there is a cone 1 having a female threaded portion 8 at the center that slides into the conical hole! Attach b9 and attach the bottom part 7 by soldering.

Further, FIG. 3 is a diagram showing the behavior of the conical shaft 9 in a state where the screw 16 is inserted into the female threaded portion 8. As shown in FIG. 3, the conical shaft 9
is pulled up while sliding on the inner plate of the notched cylinder 10, and is closely fixed to the diameter surface of the conical hole inside the notched cylinder 10, and when tightening is completed, surface contact is made as shown in Fig. 4. , a contact pressure 5 is generated. Since the radial component 4 of this contact pressure 5 acts in the direction of increasing the thickness of the cut groove 6 of the heat transfer rod 15, the cylindrical surface of the heat transfer rod 15 and the heat transfer plate 17
The inner surface of the hole generates pressure and is fixed by friction.

Returning to FIG. 1, in this embodiment, after setting micro gaps 14 for all integrated circuits by the above-mentioned means, a water cooling jacket 20 is fixed on the upper surface of the heat conduction plate 17, and water 30 is poured into the water cooling jacket. Integrated circuit 1 by flowing and cooling
It is possible to realize a mechanically safe cooling structure with low thermal resistance that is electrically insulated from water with a small gap 14 for 1 VC and does not include a vibration system.

Furthermore, by filling the minute gap 14 with an electrically insulating and thermally conductive filler, it is possible to realize a cooling structure with even lower thermal resistance.

[Effects of the Invention] The integrated circuit cooling structure of the present invention includes a substrate, an integrated circuit mounted on the substrate, a bottom surface facing the integrated circuit with a small gap therebetween, and a bottom surface facing the integrated circuit with a small gap therebetween. a cylindrical surface having a conical hole in the center serving as an element of a sliding pair capable of sliding in the σ direction; a conical shaft having an internal threaded portion bored perpendicularly to the substrate and capable of sliding in the conical hole; a heat conductive rod having a notch formed through the axis of the conical shaft and parallel to the female thread direction; a heat conductive plate having a hole forming a sliding pair with the cylindrical surface of the heat conductive rod; The heat-conducting rod consists of a male thread inserted into the female thread of the heat conduction rod, so the heat generated from the semiconductor chip is removed without intervening air, which is inefficient as a refrigerant, and without bringing solid objects into contact with semiconductor chips. The main advantage is that the heat can be effectively discharged to the outside of the device, and a cooling fJ structure with small thermal resistance can be provided.

[Brief explanation of drawings]

FIG. 1 is a side view showing one embodiment of the present invention, and FIG. 2 is a side view showing an embodiment of the present invention.
Figure 3 is a plan view and partially cut-out side view showing the configuration of the heat conduction rod; Figure 3 is a plane view and side view showing the behavior of the conical shaft of the heat conduction rod; Figure 4 is a diagram showing a screw inserted into the heat conduction rod. FIG. 5 is a cross-sectional view showing a conventional cooling structure. 6... Cut groove 8... Female thread part 9...
Conical shaft 10...Cylinder with notch 11...
・Integrated circuit 12... Board 15... Heat conduction rod 16... Male screw 17... Heat conduction plate

Claims (1)

[Claims] A substrate, an integrated circuit mounted on the substrate, a bottom surface facing the integrated circuit with a small gap therebetween, and a conical center serving as an element of a sliding pair capable of sliding in a direction perpendicular to the substrate. A cylindrical surface having a hole, a conical shaft having an internal thread that is perpendicular to the substrate and slidable in the conical hole, and a conical shaft that is bored parallel to the direction of the internal thread through the axis of the conical shaft. An integrated circuit consisting of a heat conduction rod having a notch, a heat conduction plate having a hole that forms a sliding pair with the cylindrical surface of the heat conduction rod, and a male screw inserted into the female thread of the heat conduction rod. Cooling structure.