JPH03293752A - Manufacture of heat sink for semiconductor device - Google Patents

Abstract

PURPOSE:To easily assemble the title heat sink by enlarging the diameter of a post and press-contacting and fixing plate fins with and to the outer peripheral surface of the post after the plate fins with fitting hole, the inside diameter of which is a little larger than the outside diameter of the post, are put on the post. CONSTITUTION:A cylindrical post 12 which is elongated in its axial direction with nearly same diameters and a pedestal 16 expanded in the direction perpendicular to the axial direction are formed to one body, with the pedestal 16 being formed on one end side of the post 12 in the axial direction. The inside diameter of fitting holes 20 to be formed through plate fins 14 is made a little larger than the outside diameter of the post 12 and the fins 14 are put on the post 12 by the holes 20 to such a state where the fins 14 are expanded in the direction perpendicular to the axis of the post 12 and lie upon another in the axial direction. After a roof plate 18 is put on the leading end section of the post 12 by a fitting hole 24 formed through the central part of the plate 18, the post 12 is compressed in the axial direction so as to enlarge the diameter. Therefore, the plate fins can easily be mounted on the post with excellent adhesion and with high workability.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a method for manufacturing a heat sink for a semiconductor device, and a method for manufacturing a heat sink for a semiconductor device having particularly excellent heat dissipation effects easily and with excellent mass productivity. The present invention relates to a method of manufacturing a heat sink for a semiconductor device.

(Background Art) In general, L that constitutes electric circuits in various electronic devices
For semiconductor components that generate a large amount of heat, such as ICs such as SIs and SIRISKS such as SCRs, so-called heat sinks for semiconductor devices are used to prevent the heat from increasing. As shown in Japanese Utility Model Publication No. 51-20916 and Japanese Utility Model Publication No. 55-44362, such a heat sink is constructed by attaching a semiconductor component to be cooled to a columnar post at one end in the axial direction. It has a structure in which a large number of thin plate-like plate fins that extend in the direction perpendicular to the axis are installed at predetermined intervals in the axial direction, and the heat of the semiconductor components transferred through the posts is transferred to the plate fins. In the fin portion, heat is radiated to the cooling air that is made to flow between the plate fins.

By the way, in a heat sink with this kind of structure,
Normally, it is manufactured by forming a mounting hole for each plate fin with an inner diameter that approximately corresponds to the outer diameter of the post, and fitting and fixing the plate fins to the post in the mounting hole. However, the conventional method for fixing such a plate fin to a post is to set the inner diameter of the mounting hole in the plate fin smaller than the outer diameter of the post, and press fit the post into the mounting hole. or by brazing the inner peripheral surface of the mounting hole in the plate fin to the outer peripheral surface of the post.

However, in the former method of fixing by press-fitting, if the pressure applied during press-fitting is too large, the plate fins will deform during press-fitting, so it is not possible to obtain a large pressure bonding force. It is difficult to maintain stable adhesion between the inner circumferential surface of the post and the outer circumferential surface of the post, and the heat transfer resistance between these two components tends to increase, as well as large variations in heat dissipation performance between products. The product has defects such as a lack of credibility.

On the other hand, with the latter method of fixing by brazing, brazing sometimes requires heating operations, which is cumbersome and costly. This poses a problem in that there is a risk that the problem may occur, and that a lot of effort is required to correct it.

In addition, since brazing filler metal generally has a lower thermal conductivity than the material forming the posts and plate fins, interposing the brazing filler metal between the posts and plate fins improves the conductivity between these two members. This also had the problem of increased thermal resistance and reduced heat dissipation effectiveness.

(Problem to be solved) Here, the present invention has been made against the background of the above-mentioned circumstances, and the problem to be solved is:
A large number of plate fins can be attached to a post easily and with excellent adhesion with good workability, thereby making it possible to manufacture a heat sink with excellent heat dissipation effect with high reliability. Our mission is to provide technology.

(Solution Means) In order to solve this problem, the present invention is characterized in that it extends in a direction perpendicular to the axis of a columnar post to which a semiconductor component to be cooled is attached at one end side in the axial direction. When manufacturing a heat sink for a semiconductor device in which a large number of thin plate-like plate fins are attached at predetermined intervals in the axial direction, (a) preparing the columnar posts; (c) providing the plurality of plate fins with mounting holes having an inner diameter slightly larger than the outer diameter of the post; and (d) after extrapolating the plate fins, compressing the posts in the axial direction and expanding the diameter of the posts, thereby increasing the outer peripheral surface of the posts. A heat sink for a semiconductor device is manufactured by a step of crimping and fixing the plate fin to the inner peripheral surface of the mounting hole.

(Examples) Hereinafter, in order to clarify the present invention more specifically, examples of the present invention will be described in detail with reference to the drawings.

First, FIGS. 1 and 2 show an example of a heat sink for a semiconductor device manufactured according to the method of the present invention.

The heat sink 10 includes a post 12 having a cylindrical shape in its central portion.

Further, a large number of plate fins 14 (seven in this embodiment) are attached to the post 12 at a predetermined distance from each other in the axial direction, with the plate fins 14 expanding in the direction perpendicular to the axis. Further, a pedestal 16 and a top plate 18 are provided at both ends of the post 12 in the axial direction, respectively, and the plate fins 14 and the top plate 18 have a planar shape between the two. , the above plate fin 1
4, the plate fins 14 are protected.

In such a heat sink 10, although not shown, as is well known, the post 1
2 is attached to a semiconductor component to be cooled on the side of the pedestal 16 to form a semiconductor device, so that the heat generated in the semiconductor component is transferred from the pedestal 16 via the post 12. ,
is transmitted to each plate fin 14, and the plate fin 14
In this case, heat is radiated to the cooling air that is made to flow between the plate fins 14.

By the way, when manufacturing the heat sink 10 having such a structure, first, as shown in FIG.
is formed. In this embodiment, a pedestal 16 is provided on one end of the post 12 in the axial direction and extends in the direction perpendicular to the axis.
is integrally molded. Further, as the material for forming the post 12, a material having excellent thermal conductivity and corrosion resistance in the usage environment, such as copper or aluminum alloy, is used.

Further, the plurality of plate fins 14 are formed in a separate process from the post 12. As shown in FIG. 4, the plate fin 14 has a thin rectangular flat plate shape, and is provided with a mounting hole 20 having an inner diameter corresponding to the outer diameter of the post 12 in the center thereof. A cylindrical mounting portion 22 is integrally formed at the peripheral edge of the mounting hole 20 and projects from one surface at a predetermined height.

Note that the mounting holes 2 provided in these plate fins 14
The inner diameter of 0 is set so that it does not become smaller than the outer diameter of the post 12 in order to facilitate the operation of extrapolating it to the post 12, which will be described later. It is set to a value slightly larger than the outer diameter of the post 12 to be bent so that the outer diameter of the post 12 is not much larger than the outer diameter of the post 12 so that the diameter of the post 12 is advantageously obtained.

In addition, the plate fin 14 is formed using a material that has excellent thermal conductivity and corrosion resistance in the environment of use, and is easy to press, such as copper or aluminum alloy. It is formed by punching a thin flat plate material into a rectangular flat plate shape and forming the mounting cylinder portion 22 by burring.

Next, these plate fins 14 are attached to the posts 1 in their mounting holes 2o, as shown in FIG.
By being extrapolated to the post 12, the posts 12 are overlapped in the axial direction in a state where they are spread in a direction perpendicular to the axis of the post 12, respectively.

In addition, in these plate fins 14, the protruding end surface of the mounting cylinder part 22 is brought into contact with the plate fin 14 adjacent in the axial direction, so that the protrusion of the mounting cylinder part 22 is prevented. They are superposed one on top of the other, separated from each other in the axial direction by the height.

In addition, in this embodiment, these plate fins 14
6, the top plate 18 is further inserted into the mounting hole 24 provided at the center of the post 12, and the plate fin is 14, they are arranged in an overlapping state with a predetermined distance apart in the axial direction. Note that, like the posts 12 and the like, the top plate 18 is also formed using a material with excellent thermal conductivity and corrosion resistance, such as copper or aluminum alloy. In addition, in the mounting hole 24,
Like the mounting hole 20 in the plate fin 14, it is formed with an inner diameter corresponding to the outer diameter of the post 12.

Here, as is clear from FIG. 5, the post 12 is formed to have an axial length that is longer by a predetermined dimension than the overlapping height of the plate fin 14 and the top plate 18. , thereby under the extrapolation of the plate fins 14 and the top plate 18,
The post 12 is designed to protrude above the outer surface of the top plate 18 at a predetermined height.

In this way, the plate fins 14 and the top plate 18
After being extrapolated, the post 12 is compressed by applying a compressive load in the axial direction using a suitable press machine. Through this compression process, the post 12 is plastically deformed and expanded in diameter, so that the outer peripheral surface of the post 12 is aligned with the mounting hole 20 of each plate fin 14 and the mounting hole 24 of the top plate 18. The heat sink 10 is firmly attached and fixed to the inner circumferential surface by the pressing force based on the diameter expansion deformation, thereby completing the intended heat sink 10.

It should be noted that the amount of diameter expansion of the post 12 due to such compression processing is, of course, set to such an extent that the post 12 can be brought into close contact with the mounting hole 20 of the plate fin 14, but it should also be set in consideration of the workability of the compression processing, etc. Usually, the diameter is set to a diameter expansion of about 0.1 to 1.0 nm, and this diameter expansion causes the outer peripheral surface of the post 12 to fit into the mounting hole 20 of the plate fin 14.
The inner diameter of the mounting hole 20 in the plate fin 14 is determined so that the plate fin 14 can be sufficiently closely attached to the inner circumferential surface of the plate fin 14.

Therefore, according to such a manufacturing method, the plate fin 14 is crimped and fixed to the post 12 by compression processing of the post 12 after the plate fin 14 is fitted onto the post 12. , the extrapolation of those plate fins 14 to the posts 12,
There is no need to use a large press-fitting pressure, and the workability becomes extremely easy.

In addition, in this manufacturing method, the plate fins 14 are fitted onto the post 12, and the diameter of the post 12 is expanded to press the two members 12, 14 together. During crimping, a large force is not directly applied to the plate fins 14, so a large crimping force can be applied between the crimping surfaces of the post 12 and the plate fins 14 without causing problems such as deformation of the plate fins 14. You can get it advantageously.

Therefore, by following the manufacturing method described above, the plate fin 14 can be attached to the post 12 with extremely excellent assembly workability and adhesion, and the gap between the two members 12 and 14 can be increased. Thermal conductivity can be improved, and thereby a heat sink having excellent heat dissipation effects and excellent reliability can be advantageously realized.

In particular, in the heat sink 10 according to the present embodiment, the mounting cylinder portion 22 provided on each plate fin 14 allows the interval between the plate fins 14 to be easily and accurately defined, and the plate fin 14 This also has the effect that the area of contact with the post 12 can be more advantageously secured.

Furthermore, in the heat sink 10G of this embodiment, the pedestal 16 attached to the object to be cooled is physically formed at one end in the axial direction of the post 12, so that the pedestal 16 and the post are connected to each other. 12 can be carried out with extremely low thermal resistance, which also has the advantage that even better heat dissipation effects can be exhibited.

Although the embodiments of the present invention have been described in detail above, these are literal illustrations, and the present invention is not to be construed as being limited only to these specific examples.

For example, the shape of the plate fins 14, the number of them, etc.
The plate fins 14 may be provided with protrusions, through holes (slits), etc., without being limited in any way by the description of the above embodiments, and in order to further improve the heat dissipation effect.

Further, the pedestal 16 is configured as a separate part from the post 12,
Of course, it is also possible to perform post-joining by welding, brazing, crimping, or the like. Of course, the pedestal 16 and the top plate 1
The present invention can also be advantageously applied to a heat sink having no structure.

Furthermore, in order to further enhance the heat dissipation effect of the heat sink,
Alternatively, it is also possible to form an inner hole extending in the axial direction inside the post 12 for the purpose of adjusting the amount of diameter expansion of the post.

In addition, although not listed, the present invention can be implemented in various modifications, improvements, changes, etc. based on the knowledge of those skilled in the art, and such embodiments may be different from the present invention. It goes without saying that any of these are included within the scope of the present invention as long as they do not depart from the gist of the invention.

(Effect of the invention) As is clear from the above explanation, if the method of the present invention is followed,
After the plate fin is fitted onto the post, by expanding the diameter of the post, the plate fin is crimped and fixed to the outer peripheral surface of the post.
There is no need to press-fit the plate fin into the post with a large pressure, and the assembly can be done easily.In addition, while avoiding deformation of the plate fin, a large pressure can be applied to the contact surface of the plate fin to the post. It becomes possible to exert force.

Therefore, according to the method of the present invention, the plate fin can be firmly attached to the outer circumferential surface of the post with excellent assembly workability, thereby providing excellent heat dissipation. A heat sink for semiconductor devices that can stably exhibit its effects can be easily manufactured.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing a specific example of a heat sink for a semiconductor device manufactured according to the present invention, and FIG.
It is a sectional view taken along the line ■-■ in FIG. 1. Also, Figure 3 shows
FIG. 2 is a longitudinal cross-sectional view showing a post that constitutes the heat sink for a semiconductor device shown in FIG. 1; Further, FIG. 4 is a longitudinal sectional view showing a plate fin constituting the heat sink for a semiconductor device shown in FIG. 1. Further, FIG. 5 is a cross-sectional explanatory diagram for explaining one manufacturing process of the heat sink for a semiconductor device shown in FIG. 1. Furthermore, FIG. 6 is a longitudinal sectional view showing a top plate constituting the heat sink for a semiconductor device shown in FIG. 1.

Claims (1)

[Claims] A large number of thin plate-like plate fins extending in the direction perpendicular to the axis are attached at predetermined intervals in the axial direction to a columnar post to which a semiconductor component as an object to be cooled is attached at one end in the axial direction. A method of manufacturing a heat sink for a semiconductor device, comprising: preparing the columnar post; and preparing the plurality of plate fins each having a mounting hole having an inner diameter slightly larger than an outer diameter of the post. a step of extrapolating the plate fins onto the post in their mounting holes and arranging them at a predetermined distance from each other in the axial direction, and compressing the post in the axial direction after the plate fins have been extrapolated. and crimping and fixing the outer peripheral surface of the post to the inner peripheral surface of the mounting hole in the plate fin by expanding the diameter of the post. Production method.