JP2009246319A - Heat spreader and its manufacturing method - Google Patents

Abstract

[PROBLEMS] To improve the material yield of a heat spreader to reduce the cost and improve the product accuracy such as flatness.
In a heat spreader (1), a lip portion (3) slightly elevated from the surface of a flat plate (2) is formed on the entire periphery of a flat plate (2) made of metal that is brought into contact with a heat generating component so as to be able to transfer heat. The frame divided pieces 4 a constituting the annular frame 4 by joining the end portions are joined to the peripheral portion of the surface of the flat plate 2, and the frame divided pieces 4 a connect the lip portion 3. Forming.
[Selection] Figure 1

Description

  The present invention relates to a heat spreader which is a heat diffusion plate for diffusing and transmitting heat generated from electronic components such as a central processing unit (CPU) to a wide area and a method for manufacturing the same.

  Electronic parts such as CPUs of personal computers tend to increase in heat dissipation year by year as their speed and performance increase. However, on the contrary, the chip size of the processor has become the same size or smaller than the conventional size due to the advancement of fine silicon circuit technology, and the heat flux per unit area is high. Therefore, in order to avoid problems caused by the temperature rise, it is required to effectively dissipate and cool electronic components such as a CPU.

  As a cooling method for semiconductor devices mounted on various electric devices such as personal computers and other devices, a fan is attached to the device to cool the air inside the device housing, and the semiconductor device to be cooled is cooled. Methods for attaching the body are known.

  When cooling with a cooling element attached to a semiconductor element, since the semiconductor element is generally small, heat pipes and vapor chambers are not directly attached to the semiconductor element, but once the heat is diffused to the heat diffusion plate, the heat diffusion plate Heat is dissipated from the heat pipe, heat sink, and vapor chamber attached to the heat sink (hereinafter referred to as heat spreader).

  Specifically, a heat diffusion plate is brought into contact with the semiconductor element, and a heat pipe, a heat sink, and a vapor chamber are attached to the heat diffusion plate. The heat generated by the semiconductor element to be cooled generally moves to the heat diffusion plate and is radiated from the heat diffusion plate through the heat pipe, the heat sink, and the vapor chamber.

  It is known that the thermal diffusion plate attached to the semiconductor element has a higher thermal conductivity, the thermal resistance decreases, and generally, the thermal diffusion plate is made of copper or aluminum having good thermal conductivity.

  By the way, the heat spreader that diffuses the heat to the heat source is configured by forming a sheet-like metal material into a predetermined shape by forging or the like and welding them with solder or the like. Therefore, not only is there a possibility that the heat spreader housing is thermally deformed due to heat generated during the soldering process, but when the heat spreader to be manufactured is relatively large in order to form by forging, The accuracy of the member such as smoothness may become a problem. Moreover, in order to forge-mold a sheet-like metal material, a metal material having high thermal conductivity is used up to a place where thermal conductivity is not necessary, and as a result, a cost increase factor is included.

  An example of a manufacturing method of this type of heat spreader is described in Patent Document 1. In the heat spreader manufacturing method described in Patent Document 1, the upper cover and the lower cover of the housing are each formed by forming a raised portion by pressing a sheet of metal material, and combining the members. Are configured to be diffusion bonded.

  That is, since each member is connected by diffusion bonding, for example, when copper is used as a metal material, it is possible to bond in a temperature region lower than its melting point, and thermal deformation when the members are bonded can be suppressed. It is said. In addition, by using diffusion bonding capable of bonding different metals, it is said that the desired heat spreader can be produced by combining members that meet the metal characteristics without forming a bonding interface such as solder. It is said that the thermal resistance due to the solder layer can be reduced.

JP 2006-140435 A

  The method described in Patent Document 1 described above is made in view of thermal damage or deformation due to heat at the time of manufacturing the heat spreader, but the members to be joined to each other are pressed. However, the raised portion is also formed by pressing. Therefore, the configuration described in Patent Document 1 is obtained by joining an upper cover and a lower cover that are each press-worked (particularly forged), so that there are problems such as poor material yield and reduced product accuracy. there were.

  That is, when manufacturing the upper cover or the lower cover with the raised portion by press working, a rough shape material is punched from a material such as a copper plate, and the raised portion is formed by forging to form a raised concave part. Create and trim this to create an intermediate part. Therefore, the amount of scrap generated in the process of punching and trimming increases, and the material yield is not necessarily high. Therefore, it is difficult to reduce the cost. In addition, the flat plate part of the upper cover or lower cover is inevitably loaded during the forging process, etc., and unevenness occurs in that part, resulting in a decrease in flatness and contact with heat-generating parts. There is a possibility that heat transfer with the heat-generating component is hindered.

  The present invention has been made against the background described above, and it is an object of the present invention to improve the material yield, reduce the cost of the heat spreader, and improve the product accuracy.

  In order to achieve the above object, the invention according to claim 1 is characterized in that a lip portion slightly raised from the surface of the flat plate body to the entire peripheral portion of the metal flat plate body which is brought into contact with the heat generating component so as to be able to transfer heat. In the heat spreader in which the end portions are connected to each other, the frame divided pieces constituting the annular frame are joined to the peripheral portion of the surface of the flat plate so that the frame divided pieces are A lip portion is formed.

  The invention according to claim 2 is the manufacture of a heat spreader in which a lip portion slightly elevated from the surface of the flat plate is formed on the entire periphery of the flat plate made of metal that is brought into contact with the heat generating component so as to be able to transfer heat. In the method, the flat plate body is formed as a flat plate-like component, and a plurality of frame divided pieces that are annular or square ring are formed by connecting the end portions, and the end portions of the frame divided pieces are connected to each other. Then, an annular or square annular frame is created, and each frame divided piece is joined to a peripheral portion of the surface of the flat plate to create the lip portion.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the frame body has a point-symmetrical or line-symmetric shape, and the frame divided piece is obtained by equally dividing the frame body into a plurality of parts. It is the heat spreader characterized by forming the same shape, or its manufacturing method.

  A fourth aspect of the present invention is the method of manufacturing a heat spreader according to the second or third aspect of the present invention, wherein the flat plate body and each frame divided piece are formed by press molding.

  A fifth aspect of the present invention is the heat spreader according to any one of the first to fourth aspects, wherein the flat plate body and the frame body divided piece are made of different metal materials. is there.

  According to the heat spreader according to the present invention, the plate is made of a metal flat plate and a plurality of frame divided pieces joined to the peripheral portion of the surface thereof. Therefore, it is easy to process and the material yield can be improved, so that the cost can be reduced. In addition, since the flat plate and the frame can be created separately, the flatness of the flat plate is not impaired, and the product accuracy can be improved.

  In addition, according to the manufacturing method according to the present invention, since the flat plate and the frame are separately created and joined together, the material can be taken and processed according to each component, and the processing is accordingly performed. In addition, the material yield can be improved. In particular, the frame body has an annular shape or a rectangular shape as a whole, but is composed of divided pieces, so that scrap when creating by pressing or the like can be reduced, and the material yield is improved and the cost is reduced. be able to. Furthermore, since the frame and the flat plate can be made of different metals, the cost can be reduced also in this respect.

  The bonding heat spreader according to the present invention has a flat plate shape in which the entire peripheral portion is slightly raised, and heat is transmitted to a part of the flat plate body, so that the heat is entirely transferred by heat conduction. It is configured to diffuse. An example is shown in FIG.

  The example shown here is a heat spreader 1 configured as a so-called rounded rectangle or square as a whole, and includes a flat plate body 2 that forms a so-called rounded rectangle or square. Is provided. An example of the flat plate 2 is shown in FIG. 2, which is for contacting a heat-generating component (not shown) such as a CPU and diffusing its heat. It is an excellent metal plate. The frame 4 constituting the lip portion 3 has substantially the same shape as the outline of the flat plate 2 and is made of the same kind of metal as the flat plate 2 or a different kind of metal. Further, the frame body 4 is not a so-called integral body, and is configured by combining the divided pieces 4a. FIG. 3 shows an example of the divided piece 4a, and the frame body 4 is configured by two divided pieces 4a obtained by equally dividing the frame body 4 along the axis of symmetry because the frame body 4 has a point-symmetric or line-symmetric shape. ing. Therefore, the division | segmentation piece 4a shown here has comprised what is called a mountain shape which has one corner (corner | corner part).

  Therefore, the heat spreader 1 shown in FIG. 1 is produced by arranging each divided piece 4a on the upper surface of the flat plate 2 with the respective end portions butting each other, and joining them to form the lip portion 3. Yes. The divided pieces 4a may be joined to each other by joining the end portions in advance to form the frame body 4 and placing it on the flat plate body 2, or the divided pieces 4a one by one on the flat plate body 2 one by one. You may join. The joining method of the flat plate 2 and each divided piece 4a is generally brazed, but other joining methods such as diffusion joining and laser welding may be appropriately employed as necessary.

  Next, the method for producing the heat spreader according to the present invention will be described more specifically. Since the heat spreader 1 according to the present invention is configured by joining the flat plate 2 and the frame 4 as described above, the flat plate 2 may be obtained by punching a simple plate. Therefore, for example, as shown in FIG. 4, a sheet material (thin coil material) 5 made of copper, a copper alloy, or aluminum or an alloy thereof is prepared and continuously supplied to a press machine (not shown). A flat plate 2 is obtained by punching into an appropriate shape such as a so-called rounded square or rectangle, and further performing an appropriate finish such as polishing of an edge portion. Accordingly, the flat plate 2 can be continuously formed by simple processing, and since only a relatively large load acts upon punching, not only the dimensional accuracy but also the plane accuracy should be good. Can do.

  On the other hand, the above-mentioned divided pieces 4a form a set of two, but since each has the same shape, one kind of divided piece 4a may be created. In particular, since the above-mentioned divided piece 4a has a simple corner portion, the material can be taken in a state in which the other divided piece 4a enters inside one of the divided pieces 4a. An example thereof is shown in FIG. 5. A sheet material 6 of the same kind or different kind of metal as the sheet material 5 is prepared, and the material of the divided pieces 4a is taken in a state where the corner portion and both end portions are brought close to each other. The frame 4 to be finally obtained has a shape in which the central portion is removed, but since the divided pieces 4a obtained by dividing this into symmetrical shapes are combined, the divided pieces 4a do not have a so-called hollow shape. As shown in FIG. 5, the amount of scrap is reduced by punching with a press.

  When the present inventors experimentally manufactured the heat spreader 1 having the shape described above by press working, the amount of material used is about 4% compared to the case where the bottom plate is manufactured by forging integrally with the frame body, The amount of scrap could be reduced by about 22.5%.

  Note that the present invention is not limited to the above-described specific example, and the overall shape may be other shapes such as a circle. Therefore, the shape of the divided pieces constituting the frame is also the entire heat spreader. It may be a shape that matches the shape. Further, the frame body may be composed of three or more divided pieces instead of two divided pieces. In this way, the shape of the divided pieces is further simplified, and the material yield is improved. Become advantageous. In that case, the shape of all the divided pieces is not necessarily the same, and a plurality of simplified divided pieces may be used.

It is a perspective view showing an example of a heat spreader concerning this invention in a partial cross section. It is a top view which shows the flat body. It is a top view which shows the division piece which comprises the frame. It is a schematic diagram which shows the state which has punched the flat plate. It is a schematic diagram which shows the state which has stamped the division | segmentation piece for lip | rip parts.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Heat spreader, 2 ... Flat plate body, 3 ... Lip part, 4 ... Frame body, 4a ... Divided piece, 5, 6 ... Sheet material.

Claims (5)

In a heat spreader in which a lip portion slightly elevated from the surface of the flat plate is formed on the entire periphery of the flat plate made of metal that is brought into contact with the heat-generating component so as to allow heat transfer,
The frame divided pieces constituting the annular frame by joining the end portions are joined to the peripheral portion of the surface of the flat plate, and the frame divided pieces form the lip portion. Features a heat spreader. In the manufacturing method of the heat spreader, in which the lip portion slightly raised from the surface of the flat plate is formed on the entire periphery of the flat plate made of metal that is brought into contact with the heat generating component so that heat can be transferred,
Create the flat plate as a flat part,
Create a plurality of frame division pieces that are circular or square by connecting the ends,
The ends of these frame body segment pieces are connected together to create an annular or square ring frame body, and the frame segment segment pieces are joined to the periphery of the surface of the flat plate body to create the lip portion. A method of manufacturing a heat spreader, characterized in that:   2. The frame has a shape that is point-symmetric or line-symmetric, and the frame divided pieces have the same shape obtained by equally dividing the frame into a plurality of parts. A heat spreader according to claim 2 or a method for producing the heat spreader according to claim 2.   The method for manufacturing a heat spreader according to claim 2 or 3, wherein the flat plate body and each frame body divided piece are formed by press molding.   The heat spreader according to claim 1 or 3, or the heat spreader according to any one of claims 2 to 4, wherein the flat plate and the frame divided piece are made of different metal materials. Method.

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