JPS61226946A - Cooling device for integrated circuit chip - Google Patents

Abstract

PURPOSE:To reduce pressure loss by forming the section of a refrigerant supply pipe to a non-circle such as an ellipse and arranging the pipes at both ends of a tabular cooling fin in a cooling member. CONSTITUTION:Thin flexible bellows 10 using a technique such as an electroforming technique for nickel are fixed onto the upper surfaces of cooling members 1 through soldering, etc., and connected to refrigerant flow paths 7 existing in a hat 5 in the upper section of the cooling members. The cooling members 1 are brought into pressure-contact with integrated circuit chips 2 by the resiliency of the bellows, and heat generated in the integrated circuit chips 2 is transmitted over cooling fins 13 and a refrigerant from bottom plates 12 through the pressure-contact surfaces. The sectional areas of the bellows are increased remarkably by forming the shapes of the bellows to an ellipse from a conventional circle at that time, thus reducing the velocity of flow of the refrigerant in the bellows, then lowering pressure loss and preventing corrosion. The elliptic bellows are disposed at both ends of fin rows, thus equalizing the quantity of the refrigerant flowing into each fin.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a cooling device for integrated circuit chips, and in particular to a cooling device that effectively removes heat generated from large power consuming integrated circuit chips used in electronic computers and the like. It is related to.

[Background of the invention]

In electronic computers and the like, in order to achieve high-speed circuit operation, it is widely used to mount integrated circuit chips that consume large amounts of power at high density on a wiring board such as a printed board or a ceramic board. The heat generated by this wiring board amounts to several hundred watts, and it is clear that the key to realizing a high-speed computer is to create a powerful and compact cooling system that can absorb this heat.

In order to satisfy the above-mentioned requirements, various cooling systems have been proposed in the past.
-72896 was proposed.

In this proposal, a flexible pipe member is used to supply a coolant to a cooling member that is fixedly attached to the integrated circuit chip or pressed against it by a spring, thereby cooling the integrated circuit chip. This cooling method is approximately I when using a cooling member of 1crr10
It is a powerful product that can realize low thermal resistance of C/W, but 1
111) When a spring is used to press the cooling member, the thermal resistance at the pressure interface between the chip and the cooling member becomes very large. 111) Integrated circuit chip There are limitations such as a spring load being constantly applied to the signal connection between the integrated circuit chip and the wiring board, regardless of whether the integrated circuit chip is in operation or not.

[Purpose of the invention]

An object of the present invention is to provide an integrated circuit chip that can more efficiently cool a plurality of integrated circuit chips that consume large amounts of power, and that can reduce distortion that occurs in the signal connection between the integrated circuit chip and the wiring board due to the contact pressure of the cooling member. The purpose is to provide a cooling device.

[Summary of the invention]

In order to achieve such an objective, the present invention provides springiness (i
The cooling is performed by forming a refrigerant supply pipe with a member having an inner diameter of 1.5 mm, and using the spring properties of the pipe to press a cooling member having plate-shaped cooling fins therein against the integrated circuit chip.

In this case, by making the cross section of the refrigerant supply pipe non-circular, such as an ellipse, and arranging it at both ends of the plate-shaped cooling fins in the cooling member, the cross-sectional area can be increased compared to a circular cross-section. This reduces pressure loss.

Furthermore, a groove-like uneven surface of a certain height is formed on the press-contact surface between the integrated circuit chip and the cooling member, and by engaging the two, the opposing surface area is increased and the thermal resistance of the press-contact surface is reduced.

Further, in general, in the case of an oval bellows, the spring constant for horizontal displacement in the longitudinal direction is about one order of magnitude larger than the spring constant for horizontal displacement in the longitudinal direction and the direct firing direction. Therefore, by arranging the direction of the grooves on the uneven surface in the longitudinal direction of the oval bellows, the cooling block can freely slide on the chip against horizontal displacement in the longitudinal direction of the bellows. The spring prevents unnecessary loads from being applied to the chip.

Furthermore, by inserting pressurized gas into the cooling device, the mean free path of the gas molecules is shortened, thereby preventing the generation of temperature differences between the pressurized surfaces due to the flow of free molecules.

In addition, by using refrigerant pressure to press the cooling member,
The cooling member and the integrated circuit chip are kept out of contact when the integrated circuit chip is not in operation, and the time during which unnecessary spring load or hydraulic pressure load is applied to the signal connection portion is minimized.

[Embodiments of the invention]

The present invention will be explained below with reference to the drawings.

10 is a sectional view showing an embodiment of the present invention.

Integrated circuit chip cooling apparatus 100 provides a means for encapsulating and cooling a large number of integrated circuit chips 2.

Sealing is performed by joining the wiring board 3 and the hat 5 with solder 6. On the wiring board 3, a number of integrated circuit chips 2 are electrically interconnected via solder terminals 4, and on the bottom side of the board there are a number of inputs and outputs for connecting the cooling device to a circuit card or circuit board. Pin 9 is present.

Heat generated by the integrated circuit chips 2 is transferred to the cooling member 1 mounted on each integrated circuit chip, and is cooled by a coolant circulating inside the cooling member.

The refrigerant flows from outside the cooling device through the nozzle 8a,
It circulates within each cooling member via the bellows-shaped flexible pipe 10 and is discharged to the outside of the cooling device through the nozzle 8b.

FIG. 2 is a perspective view of the cooling member. The cooling member 1 has a bottom plate 12 integrally formed with cooling fins 13 and a gap 1.
Consists of 1. As the material for the cooling fins 13, a material with good thermal conductivity, such as copper, aluminum, or highly thermally conductive silicon carbide ceramics, can be used. Also cap 11
For connection, soldering or the like may be used. Cooling member 1
On the upper surface, a thin and flexible bellows 10 made of nickel N, for example, is fixed by soldering or the like, and is connected to the refrigerant channel 7 present in the hat 5 at the top of the cooling member. Do the following. The cooling member 1 is pressed against the integrated circuit chip 2 by the spring properties of the bellows, and the heat generated in the integrated circuit chip 2 is transferred from the bottom plate 12 to the cooling fins 13 and the refrigerant via this pressure contact surface. Ru. As a refrigerant,
For example, water or Fluorinert can be used.

In this case, by changing the shape of the bellows from the conventional circular shape to, for example, an oval shape as shown in Figure 2, the cross-sectional area of the bellows can be dramatically increased, resulting in a decrease in the refrigerant flow rate within the bellows and a reduction in pressure. Loss can be reduced and corrosion can be prevented. Further, by arranging oval bellows at both ends of the fin row as shown in FIG. 2, the amount of refrigerant flowing into each fin can be made uniform.

FIG. 3 is a side view showing a second embodiment of the invention. In the embodiment described above, the pressure contact surface between the cooling member 1 and the integrated circuit chip 2 was a flat surface, but in this embodiment, as shown in FIG. 3(a), the pressure contact surface between the bottom plate 12 and the integrated circuit chip By providing minute groove-like unevenness on each side and engaging the two, the surface area of the press contact surface is effectively increased. The white arrow shown in the figure indicates the direction of engagement. Generally, as the surface m'e increases, the thermal resistance of the press contact surface tends to decrease, and by employing this embodiment, a sufficiently low thermal resistance υ can be realized. FIG. 3(b) shows the shape of the uneven surface different from that in FIG. 3(a). In this shape, since the tip of the convex part is conical, the rate of increase in surface area is smaller than in Fig. 3(a), but
Even if there is a slight misalignment between the cooling member and the integrated circuit chip, the two can be easily engaged.

As a method for processing the above-mentioned groove-like uneven surface, cutting using a diamond blade or the like is generally used, but anisotropic etching can also be used especially in the case of a silicon chip.

In the second embodiment, the case where the uneven surface is directly formed on the bottom plate 12 and the integrated circuit chip in both FIGS. 3(a) and 3(b) has been described, but as shown in the first embodiment, Even if a separately manufactured plate having an uneven surface is fixed to the flat press-contact surface with solder or the like, the above-mentioned effect will not be hindered in any way. This also applies to the embodiments described below.

FIG. 4 is a perspective view showing a third embodiment of the present invention. Generally, in an oval bellows 10 as shown in FIG. 4, the spring constant for horizontal displacement in the longitudinal direction is much thicker than the spring constant for horizontal displacement in a direction perpendicular to the longitudinal direction. Here, in this embodiment, since the direction of the grooves on the uneven surface provided on the bottom plate 12 and the integrated circuit chip 2 is formed parallel to the longitudinal direction of the bellows, cooling is prevented against horizontal displacement applied in the longitudinal direction. The member 1 can slide freely over the integrated circuit chip. Therefore, the horizontal load applied to the terminal 4 is only a relatively small value in the direction perpendicular to the longitudinal direction of the bellows, which is very advantageous in considering the destructive life of the terminal.

FIG. 5 is a perspective view showing a fourth embodiment of the present invention. In this embodiment, an intermediate plate 14 is inserted between the cooling member 1 and the integrated circuit chip 2 so that the directions of the grooves on the uneven surface are perpendicular to each other on the front and back surfaces.

In this structure, there are two heat transfer surfaces due to pressure welding, so it is disadvantageous in terms of thermal resistance compared to the second and third embodiments, but due to the uneven surfaces on both sides of the intermediate plate, In addition, the cooling block can freely slide in the direction of direct firing. Therefore, the load applied to the solder terminal 4 becomes almost zero even if the solder terminal 4 is displaced by 360 degrees in the horizontal direction, and its life can be significantly improved.

In the first to fourth embodiments described above, in order to further reduce the thermal resistance of the press-contact surfaces, it is sufficient to reduce the average distance between the press-contact surfaces. However, in this case, if the average spacing falls below the mean free path of the gas molecules in the pressure contact surface, a so-called dilute gas heat transfer condition occurs. This type of heat transfer is described in detail in Chapter 10 of ``Introduction to Heat Transfer'' by Yoshibu Kato (Yokendo), which states that in dilute gases, heat transfer due to mutual collisions of gas molecules is not possible. As a result, a temperature difference occurs between the gas in contact with the wall and the wall.

This value remains constant no matter how much the average distance between the pressure contact surfaces is reduced below the mean free path of the gas, and cannot be set to zero. In order to reduce the thermal resistance due to this temperature difference, it is effective to reduce the mean free path, that is, to increase the pressure of the sealed gas. For example, when the sealed gas is helium, in the first embodiment, Average interval 0.5
Thermal resistance of the pressure contact surface is 0.1 cm at μm1 sealing pressure of 3 atm.”
・K/W can be achieved.

FIG. 6 is a side view showing a fifth embodiment of the present invention. In this embodiment, as shown in FIG. 6(a), when the integrated circuit chip 2 is not in operation, all the cooling members 1 are not in contact with the integrated circuit chip, and in this state, the solder terminals 4 are No heavy loads will be applied. As shown in FIG. 6(b), when the integrated circuit chip is in operation, the refrigerant circulates inside the cooling member, and the cooling member 1 is moved between the integrated circuit chips 1 and 2 by the refrigerant pressure.
cooling occurs. In this embodiment, the bellows 1
0 is expanded by water pressure, the refrigerant pressure applied to the integrated circuit chip can be reduced by the load required for this, especially when the cooling device has a large pressure loss and must supply refrigerant at high pressure. It is valid.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to realize a powerful cooling device in which the heat conduction path between the integrated circuit chip and the coolant is short and has a large displacement absorption ability. Enables improved reliability and high @fake implementation

[Brief explanation of drawings]

Fig. 1 is a sectional view showing one embodiment of the present invention, Fig. 2 is a perspective view showing the cooling member thereof, Fig. 3 is a surface diagram showing the second embodiment of the invention, and Fig. 4 is a surface view showing the second embodiment of the invention. FIG. 5 is a perspective view showing a third embodiment of the invention, FIG. 5 is a perspective view showing a fourth embodiment of the invention, and FIG. 6 is a side view showing a fifth embodiment of the invention. 1... Cooling member, 2... Performance circuit chip, 3...
Wiring board, 4... Solder terminal, 5... Hat, 8...
... Nozzle, 9... Input/output pin, 10... Be "I-"
11...cap, 12...bottom plate, 13...
Fin, 14... Intermediate plate, 100... Integrated circuit chip cooling device.

Claims (1)

[Claims] 1. A cooling member having plate-shaped cooling fins inside which is connected to a refrigerant supply pipe having a spring property is pressed against the integrated circuit chip using the spring property of the pipe. An integrated circuit chip cooling device for cooling a circuit chip, characterized in that the cross section of the pipe is non-circular, and the two non-circular pipes are arranged at both ends of the fin so that their longitudinal directions are parallel to each other. Integrated circuit chip cooling equipment. 2. The press-contact surfaces of the integrated circuit chip and the cooling member each have groove-like unevenness of a certain height, and heat is transferred from the integrated circuit chip to the cooling member by engaging the uneven surfaces of both. An integrated circuit chip cooling device according to claim 1, characterized in that: 3. The direction of the grooves on the uneven surface is parallel to the longitudinal direction of the non-circular pipe, and the cooling member is slidable in the longitudinal direction when engaged. The integrated circuit chip cooling device according to item 1 or 2. 4. An intermediate plate having grooves on the concave and convex surfaces of the cooling member and the integrated circuit chip whose groove directions are perpendicular to each other and having concave and convex surfaces on the upper and lower surfaces that can be engaged with the concave and convex surfaces of the cooling member and the integrated circuit chip, respectively; The integrated circuit according to claim 1 or 2, wherein the cooling member is slidable in two mutually orthogonal directions by being inserted between the cooling member and the integrated circuit chip. Chip cooling device. 5. Claims 1, 2, 3, or 4, characterized in that a highly thermally conductive gas is sealed inside the integrated circuit chip cooling device at a pressure higher than atmospheric pressure. The integrated circuit chip cooling device described. 6. Claims 1, 2, 3, 4 or 6, characterized in that when the integrated circuit chip is not in operation, the integrated circuit chip and the cooling member are not in contact with each other. 6. The integrated circuit chip cooling device according to claim 5.