JPH02220465A - Device for cooling semiconductor device - Google Patents

Abstract

PURPOSE:To realize an effective cooling operation by a method wherein a semiconductor chip or a semiconductor package is brought into contact with a thermal conductor on a straight line or at a point. CONSTITUTION:A contact face of one of a semiconductor chip 2 or a semiconductor package and a thermal conductor 41 is formed in a square pillar shape, a conical shape or a pyramidal shape; the semiconductor chip 2 or the semiconductor package is brought into contact with the thermal conductor 41 on a straight line or at a point; one or both of contact faces are coated with a heat- conductive fluid 10. Accordingly, it is possible to reduce a change in a temperature distribution at the inside of the semiconductor chip 2 or the semiconductor package. Thereby, the semiconductor chip 2 or the semiconductor package can be cooled effectively.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cooling device for a semiconductor device suitable for removing heat generated by a semiconductor chip or a semiconductor package, and in particular, a cooling device for a semiconductor device suitable for removing heat generated by a semiconductor chip or a semiconductor package. Concerning the shape of the surface.

[Conventional technology]

As a conventional semiconductor cooling device, for example,
There is a configuration described in No.-126853.

As shown in FIG. 13, in this cooling device, a thermal conductor 4 is brought into contact with a semiconductor chip 2 mounted on a substrate 1 by a pressing force of a spring 3; A thermally conductive gas such as helium (Ha) is interposed between the surfaces and between the fins 5 of the thermal conductor 4 and the fins 7 of the cap 6 that are in contact with the water cooling jacket 8, and the heat generated from the semiconductor chip 2 is transferred to the The semiconductor chip 2 was cooled by conducting the gas to the cap 6 via the conductive gas.

(1111! Problems to be Solved by the Invention) The above prior art uses a gas such as Ha as the thermally conductive fluid interposed at the contact surface between the thermal conductor 4 and the semiconductor chip 2, so the contact thermal resistance One of the ways to reduce this contact thermal resistance is to apply thermally conductive grease with high thermal conductivity to the contact surface. When using conductive grease, the thickness of the grease layer interposed on the contact surface must be controlled to a predetermined thickness or less. However, if the contact surfaces of the thermal conductor 4 and the semiconductor chip 2 are both flat, the grease layer The thickness of the thermal conductor 4 changes depending on the type of pressure applied to the thermal conductor 4, so it is difficult to control it to a predetermined thickness. In order to follow this, a predetermined gap 9 is required between the fins 5 of the heat conductor 4 and the fins 7 of the cap 6, which has the disadvantage that the thermal resistance between the fins 5 and 7 increases. If this gap 9 is narrowed in order to reduce the resistance, the range in which the fins 5 are tilted becomes narrower, causing the problem that the thermal conductor 4 cannot follow the tilt of the semiconductor chip 2.

In addition, a cooling device as shown in Fig. 14 was developed in JP-A-52-5.
It is described in Publication No. 3547. Inside the cap 6,
The cylinder 15 is opened, and a piston 16 that conducts heat from the semiconductor chip 2 and a spring 3 that applies a pressing force to the piston 16 are inserted into the cylinder 15. Board 1 and cap 6
Highly thermally conductive helium gas is gushing out into the space surrounded by.

The heat generated from the semiconductor chip 2 is transmitted to the piston 16 via a helium gas layer interposed at the contact portion between the piston 16 and the semiconductor chip 2. Furthermore, the gas is transmitted from the piston 16 to the helium gas layer interposed in the gap 9 between the piston 16 and the cylinder 15, and is guided to the cap 6. Displacements caused by thermal deformation of the substrate 1 and cap 6 and variations in height due to the semiconductor chip 2 are absorbed by the spring 3. *The tip of the piston 16 is made to follow the slight inclination of the surface of the semiconductor chip 2 as a spherical surface, which is caused by the undulation of the surface of the substrate 1. In this case, there was the following problem.

The thermal resistance of the spherical contact portion at the tip of the piston 16 is large, accounting for nearly 40% of the total thermal resistance from the back surface of the semiconductor chip 2 to the water cooling jacket 8. One method for reducing the thermal resistance of this spherical contact portion is to apply thermally conductive grease with high thermal conductivity to the contact surface. When using this thermally conductive grease, the thickness of the grease layer on the contact surface must be controlled. However, since the contact surface has a spherical shape, if the semiconductor chip 2 is tilted, the back surface of the semiconductor chip 2 The spherical contact point at the tip of the piston 16 rotates and moves from the center of the semiconductor chip 2 toward the outer circumference. As a result, the contact surface floats up while drawing in the grease, and the thickness of the grease on the contact surface gradually increases, making it difficult to control the grease thickness. Furthermore, as the inclination of the surface of the semiconductor chip 2 increases, the contact point between the semiconductor chip 2 and the piston 16 moves from the center toward the outer circumference.
There is a problem in that the temperature distribution within the semiconductor chip 2 generally becomes large, and the operation of the semiconductor chip 2 may be adversely affected.

[Problem to be solved by the invention]

An object of the present invention is to solve the above-mentioned problems, to easily control the thickness of a thermally conductive fluid interposed between a thermal conductor and a semiconductor chip or a semiconductor package, and to easily control the thickness of a thermally conductive fluid interposed between a thermal conductor and a semiconductor chip or a semiconductor package. This makes it easier for the thermal conductor to follow, and reduces changes in temperature distribution within the semiconductor chip, reducing malfunctions of the semiconductor chip.
An object of the present invention is to provide a semiconductor device cooling device that effectively cools a semiconductor chip.

[Means to solve the problem]

The above object is to provide a cooling device for a semi-integrated device that cools a semiconductor chip or a semiconductor package by bringing a thermal conductor into contact with the semiconductor package via a thermally conductive fluid. The shape of the contact surface is prismatic, conical, or pyramidal so that the semiconductor chip or semiconductor package and the thermal conductor are in contact with each other in a straight line or at a point, and if necessary, one of the contact surfaces is made in the shape of a prism, a cone, or a pyramid. This is achieved by providing radial grooves on the surface or on the contact surfaces of both.

[Effect]

The contact surface of either the semiconductor chip or the semiconductor package and the heat conductor is made into a prismatic shape, a circular cone, or a pyramid shape, and a thermally conductive fluid is applied to either or both of the contact surfaces. When the semiconductor package and the thermal conductor are pressed against each other, the cross-sectional shape of the contact surface is wedge-shaped, so the thermally conductive fluid present at the contact surface is gradually pushed out from the tip toward the outer circumference. Then, the wedge-shaped tip comes into contact with the other contact surface and stops. As a result, the thermally conductive fluid between the semiconductor chip or semiconductor package and the thermal conductor is kept constant, so the thickness of the thermally conductive fluid can be controlled by changing the angle of the wedge shape. It becomes easier.

In addition, since the cross-sectional shape of the contact surface is wedge-shaped, even if the half-quad chip or semiconductor package is tilted, the thermal conductor will move toward the semiconductor chip or semiconductor package within the wedge-shaped angle range using the tip of the pattern as a fulcrum. Follow. At this time, the fulcrum of the wedge tip is located at the center of the contact surface and does not move, so there is no entrainment of the thermally conductive fluid and the contact point does not rise, making it easy to control the height of the thermally conductive fluid. Also, since the fulcrum at the tip of the wedge does not move from the center, half-4
Since fluctuations in temperature distribution within the semiconductor chip or semiconductor package can be reduced, it is possible to effectively cool the semiconductor chip or semiconductor package.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 3 relate to a first embodiment of the present invention.

Reference numeral 41 in FIG. 1 is a thermal conductor whose contact surface with the semiconductor chip 2 is wedge-shaped according to the present invention.

FIG. 2 is a perspective view showing the shape of this thermal conductor 41, in which the wedge-shaped surface 42 is pressed against the surface of the semiconductor chip 2 with the thermally conductive grease 10 interposed therebetween. In FIG. 1, the heat generated in the semiconductor chip 2 is transferred to the thermal conductor 41 via the thermal conductive grease 10, and the fins 5 of the thermal conductor 41
It is transmitted to the fins 7 of the cap 6 via the He gas layer, and finally transmitted to the outside by the water cooling jacket 8 in contact with the cap 6.

l of the semiconductor chip 2 and the thermal conductor 41! The thermally conductive grease 10 interposed in fl is crushed by the thermal conductor 41 by the pressing force of the spring 3 and pushed out to both sides of the ridge line 43 of the thermal conductor 41, and the ridge line 43 contacts the semiconductor chip 2.

Heat conductors according to the prior art have shapes as shown, for example, at 4 in FIG. 13 and at 16 in FIG. 14.

The surface of the semiconductor chip 2 was in contact with a plane or a cylindrical surface. Therefore, due to the pressing force of the spring 3.

It was difficult to crush the intervening thermally conductive grease to a predetermined thickness and to control the thermal resistance of the conductive grease to a predetermined value.

Compared to such conventional technology, in the present invention described above, the ridge line 43 can be easily brought into contact with the semiconductor chip 2 by the pressing force of the spring 3, so that the average thickness of the thermally conductive grease 10 can be kept constant at all times. can, therefore,
The thermal resistance value of the thermally conductive grease 10 can be set with less variation. Furthermore, if the angle formed by the wedge-shaped surface 42 of the thermal conductor 41 is widened in the flat direction, the amount of thermally conductive grease 10 sandwiched on both sides of the ridge line 43 can be reduced, so that the above-mentioned thermal resistance value can be kept low.

Furthermore, even if the semiconductor chip 2 is tilted, since the semiconductor chip 2 and the heat conductor 41 are in substantially straight contact, the tilt is absorbed by the angle formed by the wedge surface 42 of the upper rudder heat conductor 41, and the heat conduction is carried out. Fin 5 of body 41 and fin 7 of cap 6
It is possible to reduce the gap between the fins 5 and 7, and accordingly, the thermal resistance between the fins 5 and 7 can be reduced.

Furthermore, since the position of the tangent line between the ridge line 42 of the thermal conductor and the semiconductor chip 2 does not shift due to the inclination of the semiconductor chip 2, fluctuations in thermal resistance between the semiconductor chip 2 and the thermal conductor 41 can be reduced. can.

Furthermore, if the tangent line between the ridge line 42 of the heat conductor and the semiconductor chip 2 is located at the center of the semiconductor chip, when a large number of cooling devices according to the present invention shown in FIG. It is possible to reduce the temperature distribution deviation on the surface.

411th! J is a sectional view of a cooling device for a semiconductor package according to another embodiment of the present invention.

In FIG. 4, 22 is a semiconductor package containing the semiconductor chip 2, and 21 is a sealing cap thereof. The upper surface of the sealing cap 21 that contacts the bottom surface of the heat conductor 4 is formed into a wedge shape and has an angle that allows the bottom surface of the heat conductor 4 to follow the inclination of the semiconductor package 12. Thermal conductive grease 10 is interposed between the sealing cap 21 and the thermal conductor 4 as a thermal conductor.

11 to the thermal conductor 4 via the thermal conductive grease 10.
It is further transmitted from the fins 5 to the fins 7 of the cap 6 via the He gas layer, and finally removed to the outside by the water cooling jacket 8 in contact with the cap 6.

The thermally conductive grease 10 interposed between the sealing cap 21 and the thermal conductor 4 is crushed by the thermal conductor 4 due to the pressing force of the spring 3 . The thermally conductive grease 10 is pushed out from the center of the wedge tip toward the outer periphery because the cross-sectional shape of the upper surface of the sealing camp 21 that is pressed against the sealing camp 21 is wedge-shaped. and.

When the wedge tip of the sealing cap 21 comes into contact with the thermal conductor 4, the movement of the thermal conductor 4 and the thermal conductive grease stops, and a constant grease layer is maintained. Thereby, the contact thermal resistance between the semiconductor package 22 and the thermal conductor 4 becomes small, and a predetermined value is obtained. Furthermore, since the top surface of the sealing cap 21 is triangular, the bottom surface of the thermal conductor 4 follows the inclination of the semiconductor package 22, thereby reducing the gap between the fins 5 of the thermal conductor 4 and the fins 7 of the cap 6. can do. The fulcrum of the wedge tip is located at the center of the contact surface and does not move, so it does not involve the thermally conductive grease 10, and the contact point does not rise, making it easy to control the thickness of the thermally conductive grease 10. Since the fulcrum of the wedge tip does not move from the center, the average temperature and temperature distribution width within the semiconductor package 22 can be reduced, and malfunctions of the semiconductor chip 2 can be prevented.

FIG. 5 is a sectional view of a semiconductor chip cooling device according to another embodiment of the present invention. Since the wedge-shaped heat transfer plate 23 is provided on the upper surface of the semiconductor chip 2, the same effect as the embodiment of the present invention shown in FIGS. 1 and 4 described above can be obtained.

FIG. 6 is a sectional view of a semiconductor chip cooling device according to another embodiment of the present invention. In Fig. 1, a wedge-shaped surface of the thermal conductor was provided on the surface in contact with the semiconductor chip 2, but in Fig. 6,
This wedge-shaped surface is provided on the surface where the upper portion 17 of the fin 7 contacts the cap 6. *Since the effects of using the shaped parts are the same, the embodiment of the present invention shown in FIG.
The same effects as the embodiment shown in FIG. 5 can be obtained.

FIG. 7 is a perspective view showing another form of the thermal conductor according to the present invention shown in FIG. 1, and FIG. 8 is a plan view of the bottom surface thereof.

According to FIG. 7 and FIG. 8, by providing a plurality of grooves 44 on the bottom surface of the thermal conductor 45, when the thermal conductor 45 is pressed onto the semiconductor chip 2, the thermal conductive grease 10 is pushed away, and the grooves 44 Since the thermally conductive grease 10 flows into the thermally conductive grease 10, the thermally conductive grease 10 is less likely to become clogged, and the adhesion between the thermal conductor 45 and the semiconductor chip 2 is improved, and the effect of smoothing the movement of the thermally conductive grease 10 can be obtained.

FIG. 9 is a perspective view showing another type of layer of the thermal conductor of the present invention shown in FIG. 1, and FIG. 10 is a plan view of the bottom surface thereof.

In FIG. 9, by making the bottom surface of the heat conductor 46 into a conical or pyramidal shape, the heat conductor 46 and the semiconductor chip 2 are substantially in contact with each other at a point. The effect that the body 46 follows can be obtained. It goes without saying that the other effects described above can also be obtained.

FIG. 11 is a perspective view showing another form of the thermal conductor of the present invention shown in FIG. 9, and FIG. 12 is a plan view of the bottom surface thereof. Since a plurality of grooves are provided on the bottom surface of the thermal conductor 47, when the thermal conductor 47 is crimped onto the semiconductor chip 2, the thermal conductive grease 10 is pushed away and flows into the grooves 48, so that the thermal conductive grease 1o is applied to the crimped surface. Less likely to clog, heat conductor 4
This has the effect of improving the adhesion between the thermal conductive grease 7 and the semiconductor chip 2 and smoothing the movement of the thermally conductive grease 10.

Note that the bottom shape of the thermal conductor according to the present invention shown in FIGS. 7 to 12 is the same as that of the sealing cap 21 in FIG.
1 to 12, applied to the shape of the heat exchanger plate 2; 3 in FIG. 5 and the heat conductor 17 in the embodiment of FIG. 6.
It goes without saying that the same effects as the embodiment of the present invention shown in the figures can be obtained1.Furthermore, the grooves 44, 48, etc. shown in Figs. Alternatively, it can be provided on the surface of the semiconductor sealing cap 21 facing these, or on both the heat conductor and the sealing cap.

As a result, the same effects as those of the embodiments of the present invention described above can be obtained.

〔Effect of the invention〕

As described above, according to this embodiment, it is possible to easily control the thickness of the thermal conductive grease interposed between the thermal conductor and the semiconductor chip or the semiconductor package, and the slope of the semiconductor package is By making it easier for the thermal conductor to follow the flow, the thermal resistance between the semiconductor chip or semiconductor package and the water cooling jacket can be lowered.
Furthermore, variations in temperature distribution within a semiconductor chip or semiconductor package are reduced, and malfunctions of the semiconductor chip or semiconductor package are reduced.

A semiconductor device cooling device that effectively cools a semiconductor chip or a semiconductor package can be provided.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a semiconductor chip cooling device according to an embodiment of the present invention, and FIG. 2 is a perspective view of a thermal conductor of the present invention.
FIG. 3 is a plan view thereof, and FIG. 4 is a plan view thereof. 5 and 6 are cross-sectional views of a semiconductor chip cooling device according to another embodiment of the present invention, and FIGS. 7 to 12 are perspective views of a thermal conductor according to another embodiment of the present invention. The figure, the plan view of the bottom surface of the heat conductor, and FIGS. 13 and 14 are cross-sectional views of a conventional semiconductor chip cooling device. 1... Board, 2... Semiconductor chip, 3... Spring,
4゜41.45, 46.47... thermal conductor, 5,7.
...Fin, 6...Cap, 8...Water cooling jacket, 9...Gap, 10...Thermal conductive grease, 13.
... Heat exchanger plate, 14 ... Groove, 15 ... Cylinder, 16
...Piston, 17...Top of fin, 21...
Sealing cap, 22... Semiconductor package, 23...
- Wedge-shaped heat transfer plate, 42... Wedge-shaped surface, 43... Heat conduction ridge line, 44. 48... Groove. Figure 1

Claims (1)

[Claims] 1. In a cooling device for a semiconductor device that cools the semiconductor chip or semiconductor package by bringing a thermal conductor into contact with the semiconductor chip or the semiconductor package, the semiconductor chip or the semiconductor package and the thermal conductor are substantially brought into contact with each other. A cooling device for a semiconductor device, characterized in that the cooling device is in contact with the semiconductor device in a straight line or at a point. 2. In a semiconductor device cooling device that cools the semiconductor chip or semiconductor package by bringing a thermal conductor into contact with the semiconductor chip or the semiconductor package, a contact surface between the semiconductor chip or the semiconductor package and either the thermal conductor. A cooling device for a semiconductor device, characterized in that the shape is a prism, a cone, or a pyramid. 3. In the cooling device for a semiconductor device according to claim 1 or 2, one or more contact surfaces of either the semiconductor chip or the semiconductor package and the thermal conductor or both A semiconductor device cooling device characterized by having grooves.